Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Güler, Ömer(32)
- Akkurt, Nevzat(27)
- Tekin, H.O.(27)
- ALMisned, Ghada(24)
- Gul, Muhammet(20)
- Yucesan, Melih(14)
- Xu, Qian(12)
- Baykal, Duygu Sen(11)
- Güler, Seval Hale(11)
- Taşgın, Yahya(10)
- Kavaz, E.(9)
- Kilic, G.(8)
- Zengin, Gokhan(8)
- Durmus, Hasan(7)
- Guler, Omer(7)
- Xiong, Yaxuan(7)
- Yılmaz, Demet(7)
- Özkul, İskender(7)
- Yayla, Nihal(6)
- Zhang, Hui(6)
- Alkarrani, Hessa(5)
- Baloglu, Ulas Baran(5)
- Celik, Erkan(5)
- Du, Yanping(5)
- Ilik, E.(5)
- Kanca, M. Sait(5)
- Kök, Mediha(5)
- Mahomoodally, Mohamad Fawzi(5)
- Ortiz-Barrios, Miguel(5)
- Qiang, Yujie(5)
- Yang, Gang(5)
- Zakaly, Hesham M.H.(5)
- Aghakhani, S.(4)
- Basgoz, Oykum(4)
- Birdogan, Selcuk(4)
- Caprioli, Giovanni(4)
- Etli, Serkan(4)
- Guler, Seval Hale(4)
- Kahraman, Gökhan(4)
- Liu, Lin(4)
Yayınlar
- MakaleYalnız künye2024Scopus SJRQ1Predicting and optimizing maximum flexural strength of planar composite plate shear walls – concrete filled with the application of LR and RSM
Polat, Erkan; Polat, Elifcan Göçmen
Traditional theoretical models, while conservative, overlook the complex, nonlinear interactions between material and geometric parameters that influence wall flexural strength. Additionally, the extent to which these models maintain their conservative assumptions across varying parameters remains uncertain. This study aims to develop advanced predictive models for the flexural strength of planar composite plate shear walls—concrete filled (C-PSW/CF) by employing Linear Regression (LR) and Response Surface Methodology (RSM). Central Composite Design (CCD) was utilized to design numerical experiments to analyze the effects of varying parameters, including steel plate yield strength, concrete compressive strength, wall depth, depth-to-thickness ratio, and reinforcement ratio. A validated complex finite element modeling (FEM) procedure was used to analyze numerical experiments involving varying parameters of the selected variables. Both LR and RSM were applied to the generated dataset to formulate predictive equations for the maximum moment capacity of walls. Interaction plots were developed to reveal the nonlinear relationships between the variables and identify the most effective parameters influencing the wall strength. Comparisons between theoretical predictions, RSM, and LR models revealed that RSM provided the most accurate predictions, closely aligning with FEM results and effectively capturing the nonlinear interactions between wall parameters. The findings of this paper contribute to the development of more practical, accurate and optimized design methods for C-PSW/CF, ultimately improving both structural safety and efficiency.
AtıfScopus10WoS8OpenAlex10
İncele - MakaleAçık Erişim2024Scopus SJRQ1Development and in-depth experimental characterization of novel TiZrNbHfTaOx reinforced 316L stainless steel for advanced nuclear applications
Güler, Ömer; Albayrak, M. Gökhan; Başgöz, Öyküm; Kavaz, E.; Alkarrani, Hessa; ALMisned, Ghada; Tekin, H.O.
Oxide Dispersion Strengthened (ODS) materials are known for their exceptional performance in high-temperature and radiation environments. This study explores the radiation shielding properties of 316L Stainless Steel reinforced with TiZrNbHfTaOx High-Entropy Oxide (HEO). By integrating HEOs into the 316L stainless steel matrix, we aim to enhance its structural and radiation shielding properties. The HEO was synthesized using high-energy ball milling and oxidation processes, followed by thorough characterization using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). Our results indicate significant improvements in both gamma-ray and neutron shielding properties. The 316L SS samples reinforced with 20 % HEO exhibited the highest mass attenuation coefficients (MAC), lowest half-value layers (HVL), and highest effective atomic numbers (Zeff) across all tested photon energies. These enhancements are attributed to the high atomic number elements and unique synergistic effects of HEOs. Neutron shielding was evaluated through equivalent dose rate measurements, with the 20 % HEO sample demonstrating the highest absorbed dose rate percentage and superior neutron interaction cross-sections. Benchmarking against standard materials confirmed the superior performance of HEO-reinforced 316L SS, making it a promising candidate for advanced radiation shielding in nuclear reactors and other high-radiation environments. Our findings suggest that HEO reinforcement not only improves mechanical properties but also significantly enhances the radiation protection capabilities of 316L stainless steel.
AtıfScopus12OpenAlex13İncele - MakaleYalnız künye2024Scopus SJRQ2Synthesis and characterization of MgO-doped PHA bio-composites
Aydın, Handan
In this study, a highly useable MgO doped polymer composite of Polyhydroxyalkanoates (PHA), which is an alternative to conventional plastics and an environmentally friendly plastic material due to its biodegradability, was investigated. PHA-MgO composites were obtained by stirring in a suitable solution for a long time with the help of a homogenizer. Then, MgO was added and the changes in Poly Hydroxy Alkonate (PHA) polymer composites were investigated according to the changing MgO ratio. Composites were prepared by adding MgO at different ratios of 1 %, 5 %, 10 % and 15 % into PHA. The structural results of the prepared samples were investigated by using XRD (X-Ray Diffraction) and SEM (Scanning Electron Microscopy). In addition, the thermal properties of the composites were investigated by DSC (Differential Scanning Calorimetry) and TGA (Thermogravimetric Analysis). Furthermore, the optical properties of PHA-MgO composites were determined by UV-VIS spectrometry. Finally, since PHA polymer exhibits shape memory properties, the shape memory properties of the composites were also investigated.
AtıfScopus2WoS2OpenAlex3İncele - MakaleAçık Erişim2024Scopus SJRQ1A comprehensive microstructural and transmission analysis on oxide dispersion-strengthened (ODS) alloys: Impact of erbium oxide (Er2O3) concentration on physical, structural, gamma-ray, and neutron attenuation properties
Günoglu, Kadir; Güler, Seval Hale; Güler, Ömer; ALmisned, Ghada; Ozkavak, Hatice Varol; Albayrak, M. Gokhan; Akkurt, Iskender; Issa, Bashar; Tekin, H.O.
This study explores the impact of integrating varying concentrations of Erbium Oxide (Er2O3) into Oxide Dispersion Strengthened (ODS) alloys, specifically focusing on gamma-ray and neutron attenuation properties. Utilizing a 316L stainless steel matrix, Er2O3 was methodically incorporated in concentrations ranging from 1 % to 21 % by weight. The structural and radiation attenuation properties of the resultant alloys were comprehensively analyzed using techniques such as X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and experimental gamma-ray transmission studies. The results demonstrate a significant enhancement in gamma-ray shielding with increased Er2O3 content. This enhancement is quantitatively evidenced by increased linear attenuation coefficient, elevated effective Electron Density (Neff), reduced Half-Value Layers (HVL), and higher effective atomic numbers (Zeff). These findings are crucial for nuclear applications where efficient gamma-ray shielding is paramount. Conversely, a decrease in the effective removal cross section (ΣR) for neutron attenuation was observed with higher Er2O3 concentrations. This suggests a potential compromise in neutron shielding efficiency, attributed to the dilution of neutron-absorbing base elements in the alloy. Additionally, the study reveals notable changes in the microstructural properties of the alloys, including alterations in particle size, distribution, and agglomeration, influenced by varying Er2O3 concentrations. In conclusion, this research provides valuable insights into the design of ODS alloys for nuclear radiation shielding, highlighting the balance between gamma-ray attenuation and neutron shielding properties. The study's findings contribute to the development of advanced materials for safer and more efficient nuclear technology applications.
AtıfScopus20OpenAlex25İncele - MakaleYayıncıda açık erişim2024Scopus SJRQ1Revisiting the depositional age and provenance characteristics of metasedimentary rocks from the basement units in the Central Pontides (N Turkey): New constraints for tectonic evolution of the southern Black Sea region
Çimen, Okay; Ali Gücer, Mehmet; Akal, Cüneyt; Cemal Göncüoğlu, Mehmet; Arslan, Mehmet; Simonetti, Antonio; Karaoğlan, Fatih
The pre-Jurassic tectonic evolution of the Central Pontides in northern Turkey is still poorly understood due to the lack of detailed geochemical and geochronological data from the basement units. Therefore, this study reports for the first time combined whole rock geochemistry, trace element data and U-Pb ages for detrital zircons, and Ar-Ar geochronological data from the metasedimentary rocks of the Devrekani Massif, Geme Complex, and the Serveçay Unit to better understand their provenance, depositional age characteristics, and tectonic evolutions. The detrital zircon U-Pb data of metasedimentary units from the Devrekani Massif, Geme Complex, and the Serveçay Unit yield ca. 191, 185 and 298 Ma maximum depositional ages (youngest age peaks), respectively. The Devrekani Massif is dominated by Permo-Carboniferous-aged detrital zircons (67 %), whereas Neoproterozoic and Devonian-aged detrital zircons are more common in the Geme Complex (47 %) and the Serveçay Unit (53 %). These distinct age distributions clearly indicate that the Devrekani Massif may has been deposited in a dissimilar location compared to the Geme Complex and the Serveçay Unit. Furthermore, in contrast to the Devrekani Massif, the source area of the metasedimentary rocks from the Geme Complex is comparable with that of the Serveçay Unit. Lastly, the obtained detrital zircon U-Pb and mica Ar-Ar ages suggest that the Devrekani Massif and the Geme Complex were deposited and metamorphosed during the Early and Middle Jurassic, respectively. The Serveçay Unit was deposited and metamorphosed in the Permian.
AtıfScopus5İncele - MakaleAçık Erişim2024Scopus SJRQ1Local site effects at the selected stations affected by the February 6 2023 Türkiye Earthquake Sequences
Ilhan, Okan; Indır, Onur; Muratoğlu, Gamze; İçen, Abdullah; Albayrak, Kubilay; Sandıkkaya, M. Abdullah; Askan, Ayşegül; Arduino, Pedro; Taciroğlu, Ertuğrul
This paper explores the applicability of one-dimensional (1D) nonlinear (NL) and equivalent-linear (EL) site response analyses (SRA) for characterizing site effects at selected strong ground motion stations impacted by the February 6, 2023 Türkiye earthquakes. The 1D NL simulations generally underestimate site response at softer sites and for long periods likely due to basin effects and the uncertainties associated with site properties and the 1D approximation. The inclusion of the high-frequency spectral decay parameter (κ0) in 1D simulations decreases the prediction bias of nonlinear SRA, especially at soft sites for short periods. Moreover, the theoretical transfer functions (TTFs) are demonstrated to capture the fundamental site period through in horizontal-to-spectral vertical ratio (HVSR) using ground motion data before and after the February 6, 2023 main event.
AtıfScopus22OpenAlex27İncele - MakaleAçık Erişim2024Scopus SJRQ1Integrating discrete-event simulation and artificial intelligence for shortening bed waiting times in hospitalization departments during respiratory disease seasons
Ortiz-Barrios, Miguel; Ishizaka, Alessio; Barbati, Maria; Arias-Fonseca, Sebastián; Khan, Jehangir; Gul, Muhammet; Yücesan, Melih; Alfaro-Saíz, Juan-Jose; Pérez-Aguilar, Armando
Seasonal Respiratory Diseases (SRDs) usually produce a heightened number of Emergency Department (ED) attendances due to their rapid dissemination within the community and the ineffective prevention measures. Such a context requires effective management of the emergency care processes to provide in-time diagnosis and treatment to infected patients. Nonetheless, EDs have evidenced severe operational deficiencies during these periods, thereby provoking extended bed waiting times in Hospitalization Departments (HDs). Therefore, this paper presents a hybrid approach merging Artificial Intelligence (AI) and Discrete-Event Simulation (DES) to shorten the bed waiting times in HDs considering patient records collated in the first emergency care stages. First, we implemented Random Forest (RF) to estimate the probability of respiratory worsening based on sociodemographic and clinical patient data. Second, we inserted these probabilities into a DES model mimicking the emergency care from the admission to the HD. We then pretested different HD configurations and strategies seeking to reduce the HD bed waiting time. A case study of a European hospital group was used to validate the suggested framework. The AI-DES model enabled decision-makers to identify an improvement proposal with hospitalization bed waiting time lessening, oscillating between 7.93 and 7.98 h.
AtıfScopus16OpenAlex17İncele - MakaleYalnız künye2024Scopus SJRQ1Investigation of the variation of mechanical and durability properties of elements manufactured with rubber substituted SCMs with element height
Akgül, Melek; Etli, Serkan
Controlling the homogeneous distribution of granulated rubber materials added to self-compacting concrete/mortars along the height is of great importance in terms of preserving and defining the holistic behavior of structural elements. In this study, the effect of EPDMGR (ethylene propylene diene monomer granulated rubber) ratio (0 %, 5 %, 10 %, 15 %, 20 % and 25 %), test age, L/D (slenderness ratio) and element test zone (bottom, middle and top) on the mechanical properties (flexural and compressive), durability properties (porosity and sorptivity) of the elements produced with SCM were evaluated. The results obtained were statistically evaluated by GLM-ANOVA. It was observed that flexural tensile strength was strengthened up to 5 % substitution rate due to the hydrophobic properties and elasticity properties of EPDMGR used, while porosity values increased with height in the upper regions compared to the lower regions due to the placement properties of SCM. Differences in compressive strength appeared in the upper and lower sections after 5 % EPDMGR substitution. This indicates that for the mixture properties used, the properties examined in terms of mechanical and durability test results may have different properties with limited variability in terms of L/D ratio depending on the EPDMGR ratio used and the region where the element was taken.
AtıfScopus7WoS7OpenAlex10İncele - MakaleAçık Erişim2024Scopus SJRQ1Effect of curing conditions on cement based self-compacting mortar produced with mortar waste aggregate
Akgül, Melek
Concrete and mortar wastes, which have a large volume and economic value among construction demolition wastes, are the most targeted demolition waste group to be recycled. An important area where construction demolition waste can be utilized is self-compacting mortar (SCM) systems. SCMs are innovative and economical systems designed to minimize the labor requirements that are difficult to meet in the production process. In this study, mortar waste aggregate (MWA) obtained by mechanical crushing and grinding was used in SCM elements by substituting different ratios (5-10-20-30-40 %) by mass to aggregate. In this way, it was aimed to evaluate both the sustainability of MWAs and the usability of MWAs in SCMs, which are considered as a new production technology. The fresh and hardened mortar tests performed in the study are presented comparatively. The physical (dry unit volume weight, porosity), durability (capillary water absorption) and mechanical properties (flexural tensile, compressive strength) of the hardened SCM elements are based on the determinations made at 3, 7 and 28 test days and according to different curing conditions (water curing, air curing and heat curing). In addition, X-ray Diffractometer (XRD) analysis was performed on specimens obtained from 0 %, 10 %, 20 % and 40 % MWA substituted specimens after heat curing (after 7 days water curing) and 28 days water curing. In the light of the data obtained, it is reported that SCM production with 10 % MWA substitution is feasible in terms of sustainability and engineering properties evaluated in this study.
AtıfScopus2WoS1OpenAlex2
İncele - MakaleYalnız künye2024Scopus SJRQ1Effects of Er2O3 contribution on microstructure and mechanical properties of high entropy and dual phase alloys
Taşgın, Yahya; Malkoç, Aziz; Kanca, M. Sait
The study aimed to look at the differences between a high entropy alloy and a dual phase high entropy alloy with high iron and Mn content. It also wanted to find out what happened when a small amount of the rare earth element erbium oxide (Er2O3) was added to these alloys, especially on the mechanical and microstructure of the alloy. The first step in this study was to get 99 % pure metal powders, which were then made by dividing the powders into 30 g of equal weight. The powders were mixed evenly and then pressed into 10-g blocks under 6 tons of pressure. They were then set up to be melted in an arc. Four of the eight samples that were melted in an arc under vacuum were treated with heat. The four different compositions were then turned into small metallographic samples for SEM, EDX, Mapping, XRD, and microhardness tests. The study's imaging and analysis processes were also carried out. After that, SEM images were taken at various magnifications (100X, 500X, 1000X, 2500X, and 5000X), and EDS and XRD analyses were done on different structures found in these images. These analyses were based on literature research about the clarity of the metallographic images in the alloy, which showed the study's metallographic differences. The samples were put through microhardness and wear tests to see which one was stronger and less worn. The dual phase high entropy alloy (A2) was stronger and less worn than the high entropy alloy (A1). Er2O3 had little effect on the alloys' mechanical properties or microstructure. The heat treatment that was done to the samples helped the metallographic structure. In terms of physics, it didn't change the hardness much, but it did make the material wear less quickly.
AtıfScopus1WoS1OpenAlex1İncele - MakaleYalnız künye2024Scopus SJRQ1Microstructure, mechanical, and cutting performance properties of B4C and SiC reinforced sandwich composite segments
Islak, Serkan; Çelik, Ertuğrul; Erol, Mümtaz; Houssain, Hasaneen
This study aims to extend the work-life of diamond-cutting segments and to economize the operating cost of diamond-cutting tools. In order to achieve this object, bronze matrix sandwich segments reinforced with SiC and B4C were produced utilizing the hot pressing technique. In the term of the cutting segments, it is favorable that the outer layers are wear-resistant and the middle layer is tough. SEM and XRD analysis were used to determine the microstructural properties. Mechanical properties were evaluated by conducting hardness, wear, cutting performance, and three-point bending tests. The cutting performance of the segments was determined by turning andesite marble. SEM examinations showed that SiC and B4C grains were homogeneously distributed in the bronze matrix. The highest hardness value was 113.9 HB in the B4C reinforced sandwich segment. The reciprocating wear test findings indicated that the matrix exhibited the lowest wear rate in the B4C reinforced sandwich composite segment, followed by the hybrid sandwich composite segment. The lowest amount of cutting loss after turning andesite stone was achieved in the SiC, and B4C reinforced hybrid sandwich composite segment. The cutting performance of the hybrid sandwich composite segment increased by 46.15 % compared to the conventional segment without additives. The highest value of the transverse rupture strength of the specimens was 380 MPa for the B4C reinforced sandwich composite segment and 352 MPa for the hybrid sandwich composite segment. Considering all the tests and analyses, the hybrid sandwich composite segment sample may be the most suitable for diamond-cutting tools.
AtıfScopus4WoS4OpenAlex5İncele - MakaleYalnız künye2024Scopus SJRQ1Effect of boron on microstructure, thermal, and mechanical properties of Ni–B matrix diamond cutting tools
Islak, Serkan; Çelik, Ertuğrul; Houssain, Hasaneen; Danacı, Hacer Cemre
This study examines the impact of adding boron on the microstructural, thermal, and mechanical properties of Ni–B alloy matrix diamond cutting segments, which are created using the hot pressing process. Microstructure was investigated using SEM-EDS and XRD analysis. The high-temperature oxidation behavior of the samples was determined by thermogravimetric analysis. The hardness was quantified employing Vickers hardness testing, as well as, sample densities were derived based on Archimedes' principle. The wear resistance was evaluated using the reciprocating wear test method. A three-point bending test was used to examine how the diamond grains were retained inside the Ni–B matrix. The XRD investigations identified the formation of Ni, Ni3B, and Ni2B phases. The thermogravimetric analysis results showed that Ni–B alloys were exposed to oxidation at elevated temperatures as the B content increased, However, a hardness improvement was observed as the B content increased due to the formation of borides. Furthermore, the tribological investigation reveals that adding the B as reinforcement has a positive effect at a specific amount, where the optimal wear resistance and minimal friction coefficient were evident at 6% B contained sample.
AtıfScopus10WoS10OpenAlex10İncele - MakaleYalnız künye2024Scopus SJRQ1First-ever fusion of high entropy alloy (HEA) with glass: Enhancing of critical properties of zinc-tellurite glass through TiZrNbHfTaOx incorporation
Güler, Ömer; Kilic, G.; Kavaz, E.; Ilik, E.; Guler, Seval Hale; ALMisned, Ghada; Tekin, H.O.
Many oxide additives have historically been used to enhance the radiation shielding properties of glasses, yet the potential of high-entropy oxides (HEOs), which have gained popularity in material science for their unique properties, has not been explored in this context. This study is the first to investigate the radiation shielding capabilities of Zinc-Tellurite glass infused with High Entropy Oxide (HEO), specifically utilizing the novel attributes of a synthesized TiZrNbHfTa. In this study, the nuclear shielding properties of newly fabricated Zinc-Tellurite glasses doped with TiZrNbHfTaOx with a composition (25ZnO·75TeO2)100-x. (TiZrNbHfTaOx)x (x = 0, 1, 2, 3, 4 mol%) were studied. Through the synthesis of a TiZrNbHfTa HEA and its integration into glass structure, we have developed a series of novel materials with enhanced protective properties against both gamma-ray and neutron radiation. Experimental results demonstrate that the HEO-infused glass, particularly the HEC1-4 composition, significantly surpasses traditional shielding materials in neutron attenuation, evidenced by its superior effective neutron removal cross-section. Additionally, the HEC1-4 glass demonstrates improved gamma-ray shielding capabilities, with increased mass attenuation coefficients and decreased half-value layers, indicating a higher capacity for photon interaction and absorption. It can be concluded that the incorporation of High Entropy Alloys into glass matrices not only opens a new frontier in radiation shielding materials but also provides a versatile and effective solution with considerable potential for enhancing safety measures in radiation-prone environments.
AtıfScopus6OpenAlex5İncele - MakaleAçık Erişim2024Scopus SJRQ1Comprehensive metabolite and biological profile of “Sulmona Red Garlic” ecotype's aerial bulbils
Chiavaroli, Annalisa; Masciulli, Fabrizio; Ingallina, Cinzia; Mannina, Luisa; Maria Loreta, Libero; Di Simone, Simonetta Cristina; Acquaviva, Alessandra; Nilofar; Recinella, Lucia; Leone, Sheila
“Sulmona Red Garlic” is a well-known Italian traditional product. Bulbs, used for culinary purposes, have been largely investigated for their medicinal properties whereas aerial bulbils are usually removed as waste material. Here, for the first time, chemical composition and biological properties of the hydroalcoholic extract from aerial bulbils were investigated. Complementary information on metabolite composition were obtained using both NMR based untargeted and HPLC-DAD targeted methodologies. The NMR analysis revealed the presence of sugars, organic acids, amino acids, organosulphur compounds (methiin, alliin, allicin and cycloalliin), and other secondary metabolites. In particular, methiin and alliin were identified for the first time in the NMR spectra of aerial bulbil garlic extracts. Polyphenol content was determined by HPLC-DAD analysis: catechin, chlorogenic acid, and gallic acid turned out to be the most abundant phenolics. Hydroalcoholic extract blocked cell proliferation of colon cancer cell line HCT116 with an IC50 of 352.07 µg/mL, while it was non-toxic to myoblast cell line C2C12. In addition, it caused seedling germination reduction of two edible and herbaceous dicotyledon species, namely Cichorium intybus and C. endivia. Moreover, the same extract reduced the gene expression of TNF-α (tumor necrosis factor), HIF1-α (hypoxia-inducible factor), VEGFA (vascular endothelial growth factor), and transient receptor potential (TRP) M8 (TRPM8) indicating the ability to contrast cancer development through the angiogenic pathway. Final, in silico experiments were also carried out supporting the biological effects of organosulphur compounds, particularly alliin, which may directly interact with TRPM8. The results here reported suggest the potential use of garlic aerial bulbils often considered a waste product as a source in phytotherapeutic remedies.
AtıfScopus12OpenAlex13İncele - MakaleYalnız künye2024Scopus SJRQ1Evaluating sustainability of urban mobility of Asian cities: An integrated approach of interval type-2 fuzzy best-worst method and MULTIMOORA
Yucesan, Melih; Özkan, Barış; Mete, Suleyman; Gul, Muhammet; Özceylan, Eren
The motivation for sustainable urban mobility is driven by the need to create environmentally friendly, socially inclusive, economically viable, and healthier cities for current and future generations. It requires a comprehensive approach that combines infrastructure development, policy changes, behavioral shifts, and technological advancements to transform urban transportation systems. The importance of creating increasingly sustainable urban transportation is now greater than it has ever been. One of the attempts in this field is the sustainable urban transport index (SUTI) developed by the United Nations (UN). Although the SUTI has a comprehensive pool of criteria for the evaluation of mobility sustainability of cities, considering the criteria weights as equal and disregarding the uncertainties present in expert opinions is viewed as a significant drawback. To satisfy the aforementioned deficiency, a novel integrated approach including the best-worst method (BWM), multi-objective optimization by ratio analysis (MOORA) and MOORA plus full multiplicative form (MULTIMOORA) method is develloped and applied for the SUTI evaluation. In order to manage ambiguous linguistic approximations, the utilization of BWM is applied within the framework of interval type-2 fuzzy (IT2F) sets. While IT2F-BWM is used to prioritize the main and sub-indicators of SUTI, MULTIMOORA approach is applied to rank the Asian cities. The findings imply that the proposed approach not only provides a more scientific perspective but also provides the opportunity to perform sensitivity analysis on criteria weights. Therefore, the results obtained in this study are expected to help cities to create a road map for planning sustainable urban mobility (e.g. Sustainable Urban Mobility Plan).
AtıfScopus23OpenAlex26İncele - MakaleAçık Erişim2023Scopus SJRQ1Analysis of the forced convection via the turbulence transport of the hybrid mixture in three-dimensional L-shaped channel
Akkurt, Nevzat; Shedd, Tim; Memon, Abid Ali; Usman; Ali, Mohamed R.; Bouye, Mohamed
After introducing the advantage of nanofluids for optimizing heat transfer, many research articles have been written considering the different types of domains. In our article, we will observe the turbulent transport of a hybrid mixture through the three-dimensional L-shaped channel to analyze the characteristic of heat generation via forced convection. The hybrid nanofluid is composed of aluminum oxide copper (Cu) and aluminum oxide (Al2O3), which will be present in the base fluid by the volume fraction of 5%, 15%, 25%, and 35% in the base fluid (water). To analyze the forced convection, the Reynolds number (Re) will be kept at 10,000 to 40,000. The simulation will be developed using the three-dimensional κ-ϵ turbulence model and energy equations via COMSOL Multiphysics 5.6. The numerical outcomes will be verified using the literature's correlations for the average Nusselt number. It was found that the average Nusselt number at the mid of the channel is increased by increasing the volume fractions of both aluminum oxide and copper, but the rate of increase because of copper is greater than the rate of increase because of aluminum oxide. The study also suggests that to get more benefit from the transport of a hybrid mixture, keep the Reynolds number high. The temperature along the channel length is the function of mean thermal diffusivity, which is directly proportional to the volume fractions of the hybrid mixture.
AtıfScopus34OpenAlex35İncele - MakaleAçık Erişim2023Scopus SJRQ1Influence of chemical etchings on surface properties, in-vitro degradation and ion releases of 316l stainless steel alloy for biomedical applications
Say, Y.; Aslan, N.; Alla, A.M.A.; Özmen, H.
Different surface treatments are applied to improve the surface properties of metallic biomaterials. Chemical etching is one of the common techniques used for roughening the surface. In this regard, the effects of different chemical media on the surface roughness, degradation, and ion release of 316L SS steel were investigated in this study. The 316L SS steel was exposed to chemical etching in six different chemical media including HNO3, H2SO4, HCl, HClO4, NaOH and Na2CO, at four different concentrations (1, 2, 4, and 8 Molar), and at three immersion times (10, 60, and 180 min). SEM, EDS, and XRD analyses were used to examine the morphological and chemical impacts of chemical etching on sample surfaces, and roughness was measured on all sample surfaces. The effect of surface treatment on the degradation and ion release of the samples was comparatively examined. Characterization analyses indicated that the HNO3, H2SO4, and HCl media did not cause a significant reaction on the surface of the 316L SS. On the other hand, different phases were observed on the sample surfaces exposed to HClO4, NaOH, and Na2CO3 media. It was determined that the roughness had no linear correlation with the concentration and immersion time, and similarly, the degree of degradation and amount of ion release displayed no change depending on the roughness. Samples etched in H2SO4, HClO4, NaOH and Na2CO3 provided the highest roughness. It was found that H2SO4 caused a significant increase in the amount of ion release.
AtıfScopus18WoS17OpenAlex20İncele - MakaleAçık Erişim2023Scopus SJRQ2Surface Morphology, Structural, Photovoltaic and Optoelectronic Properties of Diamond Like Carbon-Copper Nanostructures
Kara, Salih; Aslan, Naim; Kurt, Mustafa Şükrü
In this work, we produced Cu doped diomond like carbon films using the magnetron sputtering technique and assessed their structural electrical and optoelectronic characteristics. In the atomic force microscopy (AFM) measurements, it was observed that the surface of the Cu-DLC nanocomposite films was in a granular form and the presence of cluster-like formations. D and G bands, which are the characteristic peaks of the DLC structure, were observed in the Raman spectrum, while Cu and C peaks were observed in the energy dispersive (EDX) spectrum. Photocurrent, photocapacitance, photosensitivity and photoresponse values increased depending on the increasing light intensity. However, the Cu-DLC/n-Si structure displayed low photovoltaic properties. The capacitance and conductance values were considerably affected by the increase in AC signal frequency. The series resistance and the density of the interface states exhibited low frequency dependent behavior which were obtained using the electrical characteristics of the nanocomposite films.
AtıfScopus7WoS7OpenAlex6İncele - MakaleAçık Erişim2023Scopus SJRQ1A comprehensive study on structural properties, photon and particle attenuation competence of CoNiFeCr-Ti/Al high entropy alloys (HEAs)
Sakar, Erdem; Guler, Omer; Alım, Bünyamin; Say, Yakup; Dikici, Burak
It is well known that high entropy alloys (HEAs) have a wide range of potential applications as radiation shielding due to their superior properties. The CoNiFeCr-Ti/Al compositions were chosen for their low cost as HEA in this study. The HEAs were successfully produced using the mechanical alloying (MA) method with equimolar CoNiFeCr, CoNiFeCrAl, and CoNiFeCrTi compositions. The production and structural properties of the alloys were investigated in detail. Besides, the photon and particle radiation shielding properties of the HEAs were calculated with the help of Phy-X/PSD, SRIM (10 keV-20 MeV), and ESTAR (10 keV-20 MeV) programs. The photon-matter interaction parameters were calculated in both specific photon energies emitted from 241Am, 133Ba, 109Cd, 60Co, 137Cs, 131I, and 22Na nuclides and a continuous energy range of 15 keV-15 MeV. The characterization of the alloys was investigated by using X-ray diffraction (XRD) and scanning electron microscopes (SEM) attached to an energy dispersive spectroscopy (EDX). It was found that the HEAs have a highly amorphous structure due to the selected production method. The crystal size of the alloys was calculated as 70, 35, and 20 nm for CoNiFeCr, CoNiFeCrAl, and CoNiFeCrTi, respectively. In terms of shielding properties, it has been determined that the produced HEAs have better shielding characteristics for photon and particle radiations than standard shielding concretes. In addition, the results demonstrated that CoNiFeCr alloy, which has the best shielding ability among the HEA alloys, can be used as a shielding material application requiring photon, electron, proton, alpha, and neutron radiations.
AtıfScopus30WoS32OpenAlex32İncele - MakaleYalnız künye2023Scopus SJRQ2A novel electrochemical sensor for metoprolol analysis based on glutardialdehyde–zinc oxide modified boron doped diamond electrode
Koçak, Berna; İpek, Yeliz; Keçeci, Ali
In this study, glutardialdehyde–zinc oxide modified boron doped diamond electrode (GA2–ZnO/BDDE) was developed as a new electrochemical sensor for the rapid, sensitive and selective determination of metoprolol (MTP). By using boron doped diamond electrode (BDDE), glutardialdehyde modified boron doped diamond electrode (GA2/BDDE) and glutardialdehyde–zinc oxide modified boron doped diamond electrode (GA2–ZnO/BDDE) separately, the electrochemical behavior of MTP on the surfaces of these electrodes was determined by applying cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. According to the results, the linear working range was 9.99 × 10−7–3.85 × 10−5 mol·L−1 and the limit of detection (LOD) was 7.53 × 10−8 mol·L−1 in pH 7 Britton–Robinson buffer solution. In addition, intraday reproducibility of peak current and peak potential were measured on the GA2–ZnO/BDDE surface and the results were calculated as 0.56 and 1 (RSD%), respectively. In order to investigate the reproducibility of GA2–ZnO/BDDE, 5 different modified electrodes were prepared with the same composition and conditions. The interday repeatability of the modified electrode was calculated as 3.13 (RSD%) and 1.05 (RSD%) for interday peak current and peak potential, respectively. The applicability of this method was confirmed by analysis of commercial drug tablets containing MTP as active ingredient. The mean recovery of the developed sensor was 95.6 % ± 1.7.
AtıfScopus14WoS12OpenAlex13İncele