Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Gul, Muhammet(102)
- Güler, Ömer(69)
- Akkurt, Nevzat(68)
- Tekin, H.O.(52)
- ALMisned, Ghada(49)
- Yucesan, Melih(49)
- Celik, Erkan(45)
- Zengin, Gokhan(40)
- Serdar, Osman(39)
- Kocabaş, Mehmet(37)
- Aslan, Naim(31)
- Baskonus, Haci Mehmet(31)
- Bulut, Hasan(31)
- Mete, Suleyman(31)
- Paksoy, Mehmet Yavuz(30)
- Kök, Mediha(27)
- Ince, Muharrem(26)
- Yildirim, Ozal(26)
- Özkul, İskender(26)
- Sulaiman, Tukur Abdulkadir(25)
- Topal, Murat(25)
- Guler, Omer(24)
- Serin, Faruk(23)
- Benzer, Fulya(22)
- Erten, Fusun(22)
- Alataş, Mevlüt(21)
- Güler, Seval Hale(21)
- Baykal, Duygu Sen(20)
- Taşgın, Yahya(20)
- Kutlu, Banu(19)
- Onat, Onur(19)
- Sahin, Kazim(19)
- Tanyol, Mehtap(19)
- Torğut, Gülben(19)
- Yildirim, Numan(19)
- Kahraman, Gökhan(18)
- Orhan, Cemal(18)
- Say, Yakup(18)
- Susam, Selim Orhun(18)
- Utku, Anıl(18)
Yayınlar
- MakaleAçık Erişim2022Scopus SJRQ1Optimization of process parameters and kinetic modelling for leaching of copper from oxidized copper ore in nitric acid solutions
TANAYDIN, Mehmet Kayra; TANAYDIN, Zümra Bakıcı; DEMIRKIRAN, Nizamettin
The leaching behavior of Tunceli malachite mineral was investigated in nitric acid solutions by two steps to evaluate the effect of various experimental parameters. In the first step, the optimal conditions for the leaching process were determined, while in the second step, a kinetic evaluation for the process was performed. In the optimization experiments, the concentration of nitric acid, temperature, stirring speed, and solid-to-liquid ratio were selected as the independent variables, and the central composite design method (CCD) was applied to the experimental data. At the end of the experiments, the optimal values for the concentration of nitric acid, temperature, solid-to-liquid ratio and stirring speed were determined to be 0.5 mol/L, 50 °C, 0.004 g/mL and 500 r/min, respectively. Under the optimal conditions, the leaching rate was found to be 99% for 120 min of reaction time. In the kinetic evaluation tests, the effects of the concentration of nitric acid, temperature, stirring speed, solid-to-liquid ratio and particle size on the leaching rate of copper from malachite were investigated. In these tests, it was determined that the leaching rate increased with the increase in the temperature, acid concentration and stirring speed, and with the decrease in the particle size and solid-to-liquid ratio. In consequence of the kinetic analysis, it was observed that the leaching kinetics followed the mixed kinetic model, and a mathematical model for the leaching process was introduced. The activation energy for this process was calculated to be 36.23 kJ/mol.
AtıfScopus18WoS17OpenAlex17
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 SJRQ3The epiphytic bryophyte succession of Picea orientalis forests on the Kümbet High Plateau (Giresun-Turkey); [Sukcesija epifitskih briofita u šumama Picea orientalis na visoravni Kümbet (Giresun-Turska)]
Ezer, Tülay; Alataş, Mevlüt; Batan, Nevzat; Erata, Hüseyin
In this study, the epiphytic bryophyte succession of Picea orientalis forests on the Kümbet High Plateau (Giresun-Turkey) were studied. A total of 21 epiphytic bryophyte species were determined (16 mosses and 5 liverworts). The epiphytic bryophyte communities were sampled in 60 sample plots taken from the trunks of Picea orientalis, each of which was 20 × 20 cm in size. The Index of Ecological Significance (IES), based on a combination of the relative frequency and mean cover of epiphytic bryophytes, was used to evaluate the abundance of bryophyte communities in epiphytic habitats on the tree trunks. In addition, multivariate classification techniques (TWINSPAN and DECORANA) were used to classify the community structures in successional stages. TWINSPAN divided the 60 sample plots into two main groups: a) the lower base communities (LB) and b) the middleupper zone communities (MU). Moreover, the middle-upper zone communities (MU) were divided into two sub-groups associated with the successional gradient (MU1 and MU2). DECORANA classified these communities along the ordination axes 1 and 3 related to the height gradient of Picea orientalis and the moisture (from mesic to xeric) gradient of the epiphytic habitat. While Exsertotheca crispa, Cynodontium fallax, Lewinskya striata, and Habrodon perpusillus were only found on old spruce trees, Drepanium fastigiatum was only found on young trees and Lophocolea heterophylla was only found on middle-aged trees.
AtıfScopus3WoS3OpenAlex3İncele - MakaleAçık Erişim2022Scopus SJRQ2Synthesis, characterization, and evaluation of antimicrobial performance of N-[3-(dimethylamino)propyl]methacrylamide based copolymer on pathogens
Pıhtılı, Güzin; Erecevit Sönmez, Pınar; Biryan, Fatih; Torğut, Gülben
In this study, poly{N-[3-(dimethylamino) propylmethacrylamide-co-acrylonitrile}; [P(DMAPMA-co-AcN)] copolymer was polymerized by free radical polymerization (FRP) in the presence of azobisisobutyronitrile (AIBN) initiator at 60°C. The structure of the synthesized polymer was characterized by the Fourier transform infrared (FT-IR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) methods. The bactericidal and fungicidal effects of the solutions prepared by adding methanol to this copolymer to prevent the growth of pathogenic bacteria, yeast, and fungi were evaluated by disk diffusion and broth microdilution method. Since the resistance of bacteria, yeast and fungi, which adversely affect human health, to antibiotics is an important issue, and there has not been any study on the antimicrobial properties of this copolymer, it has directed us to investigate its antimicrobial properties. According to antimicrobial susceptibility tests: The polymer solution showed a broad spectrum of antimicrobial action with 12.3–14.3 mm/inhibition zone diameter on Pseudomonas aeruginosa, Klepsiella pneumoniae, Enterococcus faecalis bacteria, Candida tropicalis, Epidermophyton floccosum yeast and fungi and showed a narrow spectrum of effect on inhibition of the growth of Candida albicans with 10.3 mm/inhibition zone diameter. No antimicrobial effects were observed on Staphylococcus aureus. The minimum inhibition concentration (MIC) value on the test microorganisms was determined as 125–31.25 μl. The data obtained prove that the polymer is in the same group as the interaction of bactericidal and fungicidal drugs. It is also important as a polymer with antimicrobial properties. This study aimed to produce a new polymer with antimicrobial properties. This polymer can be a new and yielding antimicrobial representative in different areas.
AtıfScopus1WoS1OpenAlex1İncele - MakaleAçık Erişim2022Scopus SJRQ1Geochemical, isotopic and U-Pb geochronological investigation of the late Cretaceous Karaçayır carbonatite (Sivas, Turkey): Insights into mantle sources within a post-collisional tectonic setting
Çimen, Okay; Ağrılı, Haşim; Kuebler, Corinne; Simonetti, Antonio; Corcoran, Loretta; Simonetti, Stefanie; Çolak, Turgut; İnal, Sedat; Dönmez, Cahit
The Karaçayır carbonatite is located within the northeastern edge of the Central Anatolian Crystalline Complex, and represents one of the significant rare earth element (REE) mineralizations in Turkey. The carbonatite intrudes the associated syenite as dikes and veins, and is mainly composed of medium- to coarse-grained calcite, and lesser amounts of apatite, mica, amphibole, pyroxene, and magnetite. This study reports new and combined geochemical, radiogenic (Sr, Pb), stable (O and C), and for the first time B and Nd isotopic ratios and in-situ U-Pb age data from the Karaçayır carbonatite. The carbonate separates from the Karaçayır carbonatite are characterized by high Ba (30 to 484 ppm), Sr (613 to 9106 ppm) and total rare earth element (TREE) concentrations (172 to 2892 ppm), which are consistent with geochemical signatures for mantle-derived carbonate melts. The combined δ18OV-SMOW (+10.7 to +19.0 ‰), δ13CV-PDB (−2.9 to +1.8 ‰) and δ11B (−13.9 to −2.9 ‰) data for a majority of the carbonate separates investigated here in contrast indicate that they are the result of open system behavior involving contamination by the country rock (marble), and/or sub-solidus, low temperature alteration. Based on the combined stable and radiogenic isotopic signatures for the least altered/contaminated samples, the carbonatite magma at Karaçayır most likely represents a low-degree partial melt of an isotopically heterogeneous (metasomatized) mantle source containing EM (enriched mantle)-like components and recycled crustal carbon; the latter finding is consistent with those recorded for young (<300 Ma old) carbonatites worldwide. A weighted mean 206Pb/238U age of 69.3 ± 1.7 Ma is obtained for apatite from the Karaçayır carbonatite, and indicates its emplacement within a post-collisional tectonic setting during the late Cretaceous.
AtıfScopus7WoS8OpenAlex7İncele - MakaleYalnız künye2022Scopus SJRQ1Heat transfer performance by forced convection of microencapsulated phase change material-latent functional thermal fluid flowing in a mini-channels heat sink
Xu, Qian; Zhu, Lidong; Yan, Xinyu; Yang, Jingbin; Wang, Zhaoxiao; Liu, DingHai; Yang, Gang; Chen, Xingli; Akkurt, Nevzat; Liu, Lin
Conventional single-phase coolants have not been able to meet the high cooling requirements of electronic devices. Microencapsulated phase change material-latent functional thermal fluid (MPCM-LFTF), a solid–liquid two-phase cooling medium, has the dual advantages of active liquid cooling and passive phase change material cooling. However, it also increases the power consumption in the mini-channels, and the cooling efficiency of MPCM-LFTF in practical applications needs to be further studied. A new MPCM-LFTF was prepared by paraffin melamine resin MPCM and base fluid (absolute ethanol and deionized water) in this work. The heat transfer performance and hydrodynamic properties were investigated using the dimensionless wall temperature and friction factor, respectively. The efficiency factor was introduced to evaluate the cooling efficiency of MPCM-LFTF in mini-channels. The experimental results showed that the addition of MPCM increased the viscosity of MPCM-LFTF, which increased the friction factor. MPCM-LFTF with a mass fraction of 15 % had the best effect of temperature control and reduced the dimensionless wall temperature by 40.5 %. However, considering the characteristics of flow resistance and improved heat transfer, MPCM-LFTF with a mass fraction of 10 % had the highest cooling efficiency and the efficiency factor was 57.0 % higher than that of the base fluid.
AtıfScopus35OpenAlex36İncele - MakaleAçık Erişim2022Scopus SJRQ3Adsorptive removal of nickel ions from wastewater by synthesized a novel biocomposite material and process optimization by response surface methodology
Ince, Muharrem; Ince, Olcay Kaplan; Alp, Hevidar
In the present study, a fixed-bed column study was performed using a novel biocomposite mate-rial, Amanita vaginata immobilized on Amberlite XAD-4 resin, to find out the adsorption behavior of nickel (Ni2+) ions from industrial wastewater. The influence of some important operating conditions including pH (3–7), biocomposite material amount (150–250 mg (XAD-4:Amanita vaginata, 5:1)) influent flow rate (4–8 mL min–1) besides Ni2+ ions initial concentration (20–40 mg L–1) on the uptake of Ni2+ solution were also optimized using a synthetic water solution. A central composite design combined with response surface methodology was utilized to maximize Ni2+ ions removal using A. vaginata immobilized on Amberlite XAD-4 resin as a biocomposite material in a column biosorption process. A mathematical model was derived from the central composite design approach for predicting responses and analysis of variance. Also, for checking model adequacy a lack of fit test was carried out. It was determined that the checked and proposed quadratic model was derived from the experimental design data. The biocomposite material adsorption capacity was calculated as 6.28 mg g–1. A high coefficient of determination (R2 = 0.9887) was presented by analysis of variance. Results confirmed that the amount of adsorbed Ni2+ amount did not change with the increase of the flow rate ratio and dose when the initial concentration of Ni2+ ions increased. The maximum adsorp-tion capacity of biocomposite material was achieved at 6.9 pH, 150.1 mg of biocomposite material amount, 7.8 mL min–1 of solution flow rate, and 39.7 mg L–1 of Ni2+ ions initial concentration. Finally, the developed method was applied to industrial wastewater to determine Ni2+ ions concentrations.
AtıfScopus4WoS4OpenAlex5İncele - MakaleYayıncıda açık erişim2022Scopus SJRQ2Does social support affect menopausal symptoms in menopausal women?
Polat, Filiz; Orhan, Ilksen; Şimşek Küçükkelepçe, Didem
Purpose: To determine the effect of perceived social support of menopausal women on their menopausal complaints. Design and Methods: This descriptive and correlational study was conducted with 505 women. The data were obtained using personal information form, menopause rating scale, and multidimensional scale of perceived social support. Frequency, percentage, t test, analysis of variance Skewness and Kurtosis (±1) and correlation were used in the analysis of the data. Findings: In the study, it was found that there was a positive and significant relationship between menopausal symptoms and social support, and menopausal symptoms decreased as social support increased. Practice Implications: Nurses should provide consultancy for women to increase their social support systems to decrease their menopausal complaints.
AtıfScopus27WoS22OpenAlex33
İncele - MakaleAçık Erişim2022Scopus SJRQ2Use of Differential Entropy for Automated Emotion Recognition in a Virtual Reality Environment with EEG Signals
Uyanık, Hakan; Ozcelik, Salih Taha A.; Duranay, Zeynep Bala; Sengur, Abdulkadir; Acharya, U. Rajendra
Emotion recognition is one of the most important issues in human–computer interaction (HCI), neuroscience, and psychology fields. It is generally accepted that emotion recognition with neural data such as electroencephalography (EEG) signals, functional magnetic resonance imaging (fMRI), and near-infrared spectroscopy (NIRS) is better than other emotion detection methods such as speech, mimics, body language, facial expressions, etc., in terms of reliability and accuracy. In particular, EEG signals are bioelectrical signals that are frequently used because of the many advantages they offer in the field of emotion recognition. This study proposes an improved approach for EEG-based emotion recognition on a publicly available newly published dataset, VREED. Differential entropy (DE) features were extracted from four wavebands (theta 4–8 Hz, alpha 8–13 Hz, beta 13–30 Hz, and gamma 30–49 Hz) to classify two emotional states (positive/negative). Five classifiers, namely Support Vector Machine (SVM), k-Nearest Neighbor (kNN), Naïve Bayesian (NB), Decision Tree (DT), and Logistic Regression (LR) were employed with DE features for the automated classification of two emotional states. In this work, we obtained the best average accuracy of 76.22% ± 2.06 with the SVM classifier in the classification of two states. Moreover, we observed from the results that the highest average accuracy score was produced with the gamma band, as previously reported in studies in EEG-based emotion recognition.
AtıfScopus29OpenAlex33İncele - MakaleAçık Erişim2022Scopus SJRQ1Free convective trickling over a porous medium of fractional nanofluid with MHD and heat source/sink
Lin, Yuanjian; Rehman, Sadique; Akkurt, Nevzat; Shedd, Tim; Kamran, Muhammad; Qureshi, Muhammad Imran; Botmart, Thongchai; Alharbi, Abdulaziz N.; Farooq, Aamir; Khan, Ilyas
Nanofluids are considered as smart fluids that can improve heat and mass transfer and have numerous applications in industry and engineering fields such as electronics, manufacturing, and biomedicine. For this reason, blood-based nanofluids with carbon nanotubes (CNTs) as nanoparticles in the presence of a magnetic field are discussed. The nanofluid traverses the porous medium. The nanofluids move on a vertical plate that can be moved. The free convection heat transfer mode is considered when the heat source and heat fluxes are constant. Convective flows are often used in engineering processes, especially in heat removal, such as geothermal and petroleum extraction, building construction, and so on. Heat transfer is used in chemical processing, power generation, automobile manufacturing, air conditioning, refrigeration, and computer technology, among others. Heat transfer fluids such as water, methanol, air and glycerine are used as heat exchange media because these fluids have low thermal conductivity compared to other metals. We have studied the effects of MHD on the heat and velocity of nanofluids keeping efficiency in mind. Laplace transform is used to solve the mathematical model. The velocity and temperature profiles of MHD flow with free convection of nanofluids were described using Nusselt number and skin friction coefficient. An accurate solution is obtained for both the velocity and temperature profiles. The graph shows the effects of the different parameters on the velocity and temperature profiles. The temperature profile improved with increasing estimates of the fraction parameter and the volume friction parameter. The velocity of the nanofluid is also a de-escalating function with the increasing values of the magnetic parameter and the porosity parameter. The thickness of the thermal boundary layer decreases with increasing values of the fractional parameter.
AtıfScopus13OpenAlex12İncele - MakaleAçık Erişim2022Scopus SJRQ1How Covid-19 pandemic and partial lockdown decisions affect air quality of a city? The case of Istanbul, Turkey
Celik, Erkan; Gul, Muhammet
The world is currently struggling with a new type of coronavirus (2019-nCoV) pandemic that first appeared in Wuhan, China, and then spread to almost all countries. As in other countries of the world, public authorities in Turkey are implementing many preventive and mitigating partial lockdown (PL) actions against the virus's effects. Some decisions and policies implemented before and after March 11, 2020, when the first virus case has been identified, have reduced people and traffic circulation, which has also turned into some improvements in air quality. At this point, this study aims to investigate how this pandemic affects the air quality of a metropolis. A case study of the city of Istanbul, the most affected city with more than half of Turkey's cases, is performed. In our analysis, we observe, compare, and discuss the impact of the COVID-19 pandemic and PL decisions on Istanbul city's air quality. We consider the particulate matter (PM10), sulfur dioxide (SO2), carbon monoxide (CO), nitrogen dioxide (NO2), nitrogen oxide (NO), nitrogen oxides (NOx), and ozone (O3) concentrations. We used data from 19 air monitoring stations (AMSs) and obtained improvements in the air quality for the pandemic period. In summary, the concentration levels in PM10, NO2, NO, and NOx result in a clear decline in pandemic times compared to the normal times in Istanbul. On the other hand, a non-homogenous trend for SO2 and CO concentrations is observed for different AMSs. A partial increase in O2 concentration is obtained in the comparison of before and during the PL period.
AtıfScopus15WoS13OpenAlex22İncele - MakaleAçık Erişim2022Scopus SJRQ3USING OBSTACLE PERFORATION, RECONFIGURATION, AND INCLINATION TECHNIQUES TO ENHANCE THE DYNAMIC AND THERMAL STRUCTURE OF A TOP-ENTRY CHANNEL
Mahdi, Khaled; Bekrentchir, Khalida; Hussein, Ahmed Kadhim; Akgule, Ali; Shanak, Hussein; Asad, Jihad; Akkurt, Nevzat; Menni, Younes
This research is to incorporate three efficient ways that will increase the perfor-mance of baffled heat exchangers. The 1st technique is represented by baffle per-forating to create pores through which secondary streams pass in order to reduce main stream pressure on the flow areas. A 2nd technique represented in redesign-ing the baffle structure by replacing its square edge with the arched edge in or-der to increase the X-velocity to facilitate the flow towards the outlet and reduce the Y-velocity to reduce the values of fluid friction with the solid areas. Finally, a 3rd way was demonstrated by using the inclined baffle model. Reinforcement of the baffle structure allowed for enhanced vortices, increased thermal gradients, and thus a reinforced thermodynamic structure over the entire heat exchanger
AtıfScopus4OpenAlex4İncele - MakaleYalnız künye2022Scopus SJRQ3Continuous Flow–Assisted Polyol Synthesis of Citric Acid Functionalized Iron Oxide Nanoparticles
Akkurt, Nevzat; Altan, Cem Levent; Sarac, Mehmet Fahri
The synthesis of nanoparticles by the continuous flow process is of great interest since it allows extensive control over reaction conditions with high precision and provides enhanced production capacity with excellent heat and mass transfer rates at high pressures and temperatures. In this study, iron oxide nanoparticles were synthesized via continuous flow process in combined micro- and milli-sized reactors in the presence of citric acid at variable functional ratios from 1:1 to 1:5. The results illustrated the possibility of continuous production of superparamagnetic magnetite and/or maghemite nanoparticles at the size range of 4.3 to 4.6 nm that exhibit remarkable colloidal stability in triethylene glycol (TEG) and saturation magnetizations up to 52 emu/g. Additionally, the nucleation and growth stages of nanoparticles were found to be unaffected by the presence of citric acid (CA) while an increase in the functional ratio was shown to affect the magnetic properties due to the presence of a non-magnetic layer around the particles. Furthermore, the viability of human lung adenocarcinoma (A549) cell lines was investigated with several concentrations of magnetic nanoparticles, and the biocompatibility of nanoparticles was illustrated at certain particle loadings after 48 h expressing the potential use in biomedical applications.
AtıfScopus9WoS9OpenAlex9İncele - MakaleYalnız künye2022Scopus SJRQ2Detailed Chemical Characterization and Biological Propensities of Malabaila lasiocarpa Extracts: An Endemic Plant to Turkey
Zengin, Gokhan; Zheleva-Dimitrova, Dimitrina; Babacan, Ebru Yüce; Polat, Rıdvan; Çakılcıoğlu, Uğur; Sadeer, Nabeelah Bibi; Costa, Emmanoel V.; Mahomoodally, Mohamad Fawzi; Naviglio, Daniele; Gallo, Monica
This study focused on the biological evaluation and chemical characterization of Malabaila lasiocarpa Boiss. (M. lasiocarpa) (Family: Apiaceae). The phytochemical profile, antioxidant, enzyme inhibitory of the methanolic, aqueous, dichloromethane, hexane extracts were investigated. Based on UHPLC-HRMS analyses, a total of 101 peaks were annotated or identified for the first time in M. lasiocarpa extracts. They include hydroxybenzoic, hydroxycinnamic, acylquinic acids and their glycosides, C- and O-glycosyl and O-diglycosyl flavonoids. In addition, 10 simple mono- and disubstituted coumarins together with 10 furanocoumarins were tentatively annotated. The methanolic extract possessing the highest phenolic (24.36±0.60 mg gallic acid equivalent/g extract) and flavonoid (69.15±0.37 mg rutin equivalent/g extract) content also exhibited the strongest radical scavenging potential against 2,2-diphenyl-1 picrylhydrazyl (21.73±0.42 mg Trolox equivalent/g extract, respectively), and highest reducing capacity (57.81±0.97 and 28.00±0.40 mg Trolox equivalent/g extract, for cupric reducing antioxidant capacity and ferric reducing antioxidant power, respectively). The dichloromethane extract substantially depressed the tyrosinase (73.92±5.37 mg kojic acid equivalent/g extract), α-amylase (0.63±0.01 mmol acarbose equivalent/g extract) and α-glucosidase (0.69±0.02 mmol acarbose equivalent/g extract) enzymes. This study has produced critical scientific data on M. lasiocarpa which are potential contenders for the development of novel phyto-pharmaceuticals.
AtıfScopus6OpenAlex5İncele - MakaleYalnız künye2022Scopus SJRQ2Microstructure and corrosion investigation of FeCoCrNiMo0,5(MnAl)0,3 high entropy alloy produced by 316 L stainless steel scrap
Cihangir, Salih; Say, Yakup; Ozkul, İskender; Guler, Omer; Guler, Seval Hale
FeCrCoNiMo0,5(MnAl)0.3 high-entropy alloy (HEA) was manufactured via arc melting process by adding the related metal powders into scrap of 316 L stainless steel for corrosion resistance tests under salt and acid conditions. Cyclic potentiodynamic polarization experiments performed under acidic conditions revealed pre-passivation due to abundance of network modifying metals in HEA composition which was further analyzed by electrochemical impedance spectroscopy. Elemental resolved analysis of leftover solutions was used to compare metal ions released during corrosion. X-ray diffraction analysis indicated the phase change in heat treated HEA samples. Non-heat treated HEA samples can be compared with stainless steel under moderate corrosion conditions and had better hardness results.
AtıfScopus20WoS17OpenAlex19İncele - MakaleAçık Erişim2022Scopus SJRQ3Effects of kefir supplementation on body antioxidant-systems, haemolymph heat-shock protein 70 and trypsin, in the crayfish Astacus leptodactylus Eschscholtz (Decapoda, Astacidea)
Aksu, Önder; Türkoǧlu, Semra; Can, Erkan; Erişir, Mine; Kocabaş, Mehmet; Kayim, Murathan; Benzer, Fulya
This study was designed to investigate the effects of dietary kefir on trypsin, heat shock protein 70 (HSP70) as well as the oxidant and antioxidant status of the freshwater crayfish, Astacus leptodactylus. The experiment was performed with the four following treatments: Control group, D1, D2 and D3 (kefir supplemented diet 2, 4, 8 g/kg of crayfish body mass, respectively). Crayfish were stocked into 12 fibreglass tanks (three replicates per treatment) and fed for 45 days. Reduced glutathione (GSH), glutathione peroxidase (GSH-Px), malondialdehyde (MDA) and catalase (CAT) in hepatopancreas and muscle were analysed to determine the status of the oxidant/antioxidant balance. In addition, HSP70 and trypsin were measured in haemolymph. Our results indicated that the activity of GSH-Px, MDA and GSH levels decreased in hepatopancreas ( p > 0.05) and muscle tissues ( p < 0.05) with increasing kefir concentration, while CAT activity increased ( p < 0.05). Trypsin and HSP70 insignificantly decreased in haemolymph.
AtıfScopus1WoS1OpenAlex1İncele - MakaleYayıncıda açık erişim2022Scopus SJRQ1Compressible unsteady steam flow and heat transport analysis: a numerical investigation
Hussain, Azad; Arsaln, Muhammad; Rehman, Aysha; Alharbi, Fahad M.; Akkurt, Nevzat; Eldin, Sayed M.; Althobaiti, Saad
The unsteady compressible steam laminar flow associated with heat transfer in fluids in a squared cylinder is examined in this work. The current challenge was created utilizing the CFD approach. The laminar flow is chosen with a low Mach number. With the geometric wall, the flow has a no-slip condition. The pressure on the flow is kept at 0 pas, and the temperature in the flow regime is 305.13. A 0.5 m/s velocity is used to start the flow. With the use of graphics, the effects of time on velocity and pressure distributions are discussed. Different outcomes are also mentioned, such as drag coefficients, lift coefficients, and heat distributions. The velocity drops from 2.5 to 1.6 m/s at t = 7 s in the absence of anybody's force and temperature 305.13 K. Pressure increases from 0.00098 to 0.001 Pas in the flow interval of 10 s. Surface temperature increases from 360 to 375 K in time intervals of 10 s keeping pressure constant. And contour temperature increases from 371.56 to 374.2 K in time intervals of 10 s keeping the pressure constant. This information provides us with caution about the emission of steam from the chimneys of furnaces. It implies that when steam flows from a cylindrical geometry like chimneys of furnaces it heats the upper inner and outer parts which may destroy the material. So for safety, that emission should be taken for a short interval of time otherwise it will result in a havoc process. The lift coefficient remains constant and the drag coefficient increases from 0.0005 to 0.065. Under that condition, fluid has to face more resistance. To overcome that difficulty fluid should be provided with high velocity to continue it for a long time. The technique used to solve modeled problems is the Backward Difference Formula.
- MakaleYalnız künye2022Scopus SJRQ3On the investigation of a discontinuous Sturm-Liouville operator of scattering theory
Akcay, Ozge
This paper deals with the investigation of the direct scattering problem for the Sturm-Liouville operator containing both the discontinuous coefficient and discontinuity conditions at some point on the positive half-line. The integral representation of the Jost solution is obtained and the properties of its kernel function are given. A total collection of the scattering data is constructed and the behavior of the scattering function at infinity is examined.
AtıfScopus2İncele - MakaleAçık Erişim2022Scopus SJRQ3The use of Phanerochaete chrysosporium as an alternative bioremedia-tion tool of heavy metal, chemical oxygen demand and phosphate from landfill leachate
Yildirim, Numan; Kardas, Elif; Ince, Muharrem
In this study, in order to investigate the bioremediation efficiency of Phanerochaete chrysosporium, chemical oxygen demand (COD) reduction, total phosphate levels and heavy metal (Fe2+, Mn2+, Zn2+ and Cu2+) removal were determined in five different experimental groups (control, X, Y, Z, and T) under static culture conditions containing leachate at different incubation periods (5, 10, and 20 d). At the end of the 20th day of incubation, 84% Mn2+ and Zn2+ removal was achieved in X application group. In the same application group, 90.88% COD reduction was also obtained. The lowest total phosphate value was determined as 2.63 g L–1 in T group compared with control group (5.0 g L–1). Similar improvements have been identified in other application groups in terms of metal removal, total phosphate levels and COD reduction. As a result, the findings obtained from our study show that white rot fungus P. chrysosporium can be used as an alternative biological resource in the studies for improving landfill leachate in terms of metal removal efficacy, COD and total phosphate level reduction capacity.
AtıfScopus3WoS1OpenAlex3İncele - MakaleYalnız künye2022Scopus SJRQ2Fe3O4 nanoparticle decorated novel magnetic metal oxide microcomposites for the catalytic degradation of 4-nitrophenol for wastewater cleaning applications
Hasanoğlu Özkan, Elvan; Aslan, Naim; Koç, Mümin Mehmet; Kurnaz Yetim, Nurdan; Sarı, Nurşen
Co3O4, NiO and ZnO microparticles were decorated with Fe3O4 nanoparticles where novel Co3O4@Fe3O4, NiO@Fe3O4 and ZnO@Fe3O4 microcomposites were obtained with significant magnetic properties. Decorating microparticles with Fe3O4 nanoparticles helped us to obtain microcomposites with outstanding magnetic characteristics, since Fe3O4 nanoparticles were decorated on the upper shell of the microstructures where the magnetic characteristics of the composites were not suppressed, and good catalytic performance was obtained. SEM was used to assess the physical morphology of the microparticles which indicate that microparticles were in flower or ball-like shape. Magnetic properties were checked using VSM which revealed that magnetic composites are in ferromagnetic characteristics. Optic characteristics of the particles were checked by UV–Vis spectrometry to assess bandgap energies which indicate that doping microparticles with Fe3O4 slightly alters the bandgap energies of microparticles. The catalytic role of microparticles and microcomposites for the catalytic reduction of 4-nitrophenol to 4-aminophenol was studied.
AtıfScopus21WoS22OpenAlex18İncele