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
- MakaleYalnız künye2020Scopus SJRQ2The Effects of Boron Minerals on the Microstructure and Abrasion Resistance of Babbitt Metal (Sn–Sb–Cu) Used as Coating Materials in Hydroelectric Power Plants
Tasgin, Yahya
In this study, the microstructure of a new alloy is examined which is created by adding boron oxide (B2O3), boric acid (H3BO3) and kolamanit (Ca2B6O11·5H2O) in certain proportions to the white metals (Sn–Sb–Cu) used in the carrier bearing dies of vertical Francis turbines in hydroelectric power plants. The Babbitt materials were coated with electric arc spray coating method before. Also it is examined that whether the coating material produced as a new alloy is appropriate for applying to die surface. Utility of the new white metal material in carrier bearing dies in hydroelectric power plants has been investigated based on the metallographic structure and wear of the new alloy. While some of the boron elements added to the Babbitt metal have positive results in terms of metallographic and abrasion values, some of the boron elements have negative effects.
AtıfScopus13OpenAlex14
İncele - MakaleYalnız künye2020Scopus SJRQ3Kinetic models for the extraction of copper by Acorga M5640 after leaching of malachite ore in perchloric acid solutions and the stripping of copper from loaded organic phase
Tanaydın, Mehmet Kayra; Demirkıran, Nizamettin
In the present work, the extraction kinetics of copper using the resulting actual leach solution obtained from the leaching of malachite ore in perchloric acid solutions and the stripping kinetics of copper from the loaded organic phase were examined. The organic phase was prepared by using Acorga M5640 and kerosene. In the extraction process, the effects of the initial pH of aqueous solution, initial concentration of copper, extractant concentration, temperature, and stirring speed on the extraction rate were investigated. In the stripping process, the effects of the concentration of perchloric acid, temperature, stirring speed, and extractant concentration on the stripping rate were examined. It was determined that the extraction rate increased with increasing the initial pH of aqueous solution, stirring speed, extractant concentration and temperature, and with decreasing the initial concentration of copper ions. In the stripping process, it was observed that the stripping rate increased with increasing the concentration of perchloric acid, temperature and stirring speed, and with decreasing the extractant concentration. It was determined that both the solvent extraction and stripping processes could be described by the first order pseudo homogenous reaction model. The activation energy for the extraction and stripping processes was calculated to be 50.04 kJ/mol and 32.42 kJ/mol, respectively.
AtıfScopus8WoS7OpenAlex10
İncele - MakaleYalnız künye2020Scopus SJRQ2Evaluation of the gamma and neutron shielding properties of 64 TeO 2+ 15 ZnO + (20 - x) CdO + xBaO + 1 V 2O 5 glass system using Geant4 simulation and Phy-X database software
Aşkin, A.
In this study, fast neutron removal cross-section and γ-ray shielding capabilities in terms of mass attenuation coefficient (μm), transmission fractions (T), effective atomic numbers (Zeff), half-value layer (HVL) and exposure build-up factors (EBF) of the 64 TeO 2+ 15 ZnO + (20 - x) CdO + xBaO + 1 V 2O 5 (x= 0 , 5 , 10 , 15 , 20 mol%) glass system have been evaluated using Monte Carlo simulations carried out with Geant4 model of the high-purity germanium (HPGe) detector and Phy-X database software. The results of this study revealed that γ-ray shielding capability of the studied glass system increases with the increase of BaO content and decrease of CdO content in the chemical structure due to the high atomic number (Z) of Ba compared to Cd. The results also showed that increase of BaO fraction in the glass structure weakens the neutron shielding ability and by the use of low Z elements in the composites better shielding performance against neutrons can be obtained.
AtıfScopus7WoS6OpenAlex6İncele - MakaleAçık Erişim2020Scopus SJRQ2Electrical properties of two-armed poly(Ɛ-CL-co-BMA) composites filled with bentonite
Pihtili, Güzin; Torğut, Gülben; Biryan, Fatih
The dielectric and electrical conductivity properties of two-armed poly(Ɛ-CL-co-BMA) copolymer and adding bentonite forms were studied. The effect of the bentonite was investigated at different quantities (%3wt, %6wt, %15 wt). The measurements were performed at frequencies between 100 Hz to 10 kHz at room temperature, and the dielectric permittivity (ε′), the dielectric loss factor (ɛ″) and conductivity (σac) were calculated. ε′ and ɛ″ increased with increasing bentonite content. In addition, changes of susceptance (B) and impedance (IZI) were examined at different frequencies ranging from 100 Hz to 10 kHz in order to investigate the effect of bentonite loading. As frequency increases, (B) increases linearly, whereas IZI decreases and remains constant at high frequencies. Two-armed copolymer synthesized using ring-opening polymerization (ROP) and Atom Transfer Radical Polymerization (ATRP) and its composites prepared with bentonite were characterized by FT-IR, 1H-NMR and SEM. Thermal behaviors were examined by TGA and DSC methods and the effect of bentonite was discussed.
AtıfScopus15WoS14İncele - MakaleYalnız künye2020Scopus SJRQ2Temporal and seasonal variations in phytoplankton community structure in Uzuncayir Dam Lake (Tunceli, Turkey)
Kutlu, Banu; Aydın, Rahmi; Danabas, Durali; Serdar, Osman
Seasonal variations in species composition and growth dynamics of phytoplankton in Uzuncayir Dam Lake (Tunceli, Turkey) were studied in relation to ecological factors by collecting horizontal water and phytoplankton samples for over a year. A total of 46 phytoplankton taxa were recorded, where Bacillariophyta was the most abundant in species number representing 24 taxa. Diatoms were the most conspicuous phytoplankton in terms of abundance as well as occurrence frequency. Charophyta, Chlorophyta, Cyanobacteria, Ochrophyta, Miozoa, and Euglenozoa were the least abundant. However, some Diatoms (Gyrosigma attenuatum, Hippodonta hungarica, Meridion circulare, Nitzschia clausii, Nitzschia frustulum, Pantocsekiella ocellata, Rhoicosphenia abbreviata), Charophytes (Cosmarium granatum, Mougeotiopsis calospora), Cyanobacteria (Leiblenia epiphytica, Planktothrix agardhii); Dinoflagellates (Ceratium hirundinella, Parvodinium africanum, Parvodinium inconspicuum, Peridinium cinctum), and Ochrophyta (Dinobryon pediforme) were also noticeable, with their occurrence in all seasons. Canonical correspondence analysis (CCA) and principal component analysis (PCA) were employed to analyze the relationship between occurrence and abundance of phytoplankton species as well as the ecological factors. The results showed that pH and the concentrations of NH4, NO3, and PO4 influenced seasonal occurrence and abundance of phytoplankton species in the lake. Uzuncayir Dam Lake may be classified as an oligotrophic lake with the mean value of nitrate 2.62 mg L−1 and phosphate 0.23 mg L−1 as supported by the occurrence of various phytoplankton groups. Findings related to pollution indices yielded that Uzuncayir Dam Lake is on the edge of the moderate state of organic pollution.
AtıfScopus26WoS15OpenAlex23
İncele - MakaleYalnız künye2020Scopus SJRQ3Increasing the Power Generation by Raising the Capacity of the Thrust Bearing Oil Cooling System in Hydroelectric Power Plants
Kahraman, Gökhan
Cooling capacity decreases due to faults appearing over time in the thrust bearing oil cooling systems of hydroelectric power plants and cooling process cannot proceed sufficiently. For this reason, while the turbine-generator unit generates energy, the thrust bearing heats up. This temperature problem prevents the unit from operating at full capacity and therefore decreases in energy production. Producing deficient energy in hydroelectric power plants, which is a renewable energy source, causes long-term economic losses for countries. In this study, the thrust bearing cooling system of a vertical Francis turbine, which produces 150 MW of energy per hour, is investigated. The reduction in the cooling capacity over time in turbine thrust bearing cooling system is solved by using exchanger system with additional plate and the power produced by the turbine-generator unit is increased 15 MW/h. This improvement has greatly contributed to the national economy. The method of increasing the cooling capacity applied to the hydroelectric power plant thrust bearings can be applied to all hydraulic turbines. This method will increase the energy production amount of the unit by approximately 10% and it costs approximately 80% cheaper than completely replacing the existing cooling system.
AtıfScopus5WoS2OpenAlex5İncele - MakaleAçık Erişim2020Scopus SJRQ1Thermal Image Processing Technique for Determination of Temperature Distributions of Minced Beef Thawed by Ohmic and Conventional Methods
Döner, Deniz; Çokgezme, Ömer Faruk; Çevik, Mutlu; Engin, Mustafa; İçier, Filiz
In the present study, the effectiveness of ohmic thawing (OT) on temperature distribution (TD) was evaluated by using a non-destructive measurement method: thermal imaging (TI). The effects of both OT process parameters and sample properties on TD of thawed minced beef were determined. Thermal images were taken from the central cross-sectional area of a thawed sample. In the first part of the study, the effects of OT system parameters (voltage gradient; 10–13–16 V/cm and electrode type; E1:titanium foil electrode with a smooth surface, E2: needled-type titanium electrode, E3: titanium electrode with pyramid surface shaped) and sample shape (X: 13 × 4 × 3 cm3; Y: 13 × 6 × 2 cm3; Z: 13 cm height × 3.91 cm diameter) were analyzed in detail. The best thawing condition (electrode type E2 and sample shape Y) was determined by taking into account of thawing time and TD properties obtained from a developed TI processing technique. In the second part of the study, the effects of OT process on TD properties of minced beef having different fat contents (2–10–18%) were compared with those of two different conventional thawing processes (stationary cold ambient + 4 °C -RT and under cold running water + 4 °C -WT). The percentage of thawed portions in central section was above 68% for OT and varied between 12 and 54% for CT. Rectangular-shaped samples had more homogeneous temperature distributions than cylindrical samples (p < 0.05). TI could be used to control the process by non-destructive monitoring of temperature during OT.
AtıfScopus36WoS31OpenAlex35İncele - MakaleAçık Erişim2020Scopus SJRQ2The effect of graphene nanoplatelets on technical properties of micro- and nano-sized TiO2 matrix: a comparative research study on electrical and optical characteristics
Güler, Ömer; Ayhan, Hakan; Başgöz, Öyküm; Yavuz, Çağdaş; Albayrak, M. Gökhan; Evin, Ertan; Safa, Hasan; Yahia, Ibrahim S.
In this study, titanium dioxide (TiO2)-based graphene nanoplatelets (GNPs)-reinforced composite materials were produced and the electrical and optical properties of the composite materials were investigated. Graphene, which was used as a reinforcing material, was produced by using liquid-phase exfoliation method. While the TiO2 used as matrix material was commercially available for the first group of samples, it was produced by using the sol–gel method for the second group of the samples. Different rates of graphene were added to the TiO2 powders which were commercially available and produced by using sol–gel method. GNPs used as a reinforcing material were subjected to TEM analysis. The resulting composite materials were structurally examined in SEM and XRD. Then, the changes in electrical conductivity of these composites under the impact of temperature were measured. UV–Vis spectrometers of the samples were taken and their optical properties were determined. When temperature-based electrical examination of the produced composite materials was performed, an increase was observed on the electrical conductivity values in both groups of samples as a result of addition of the reinforcing element. In addition, TiO2-containing composites produced by using sol–gel method had lower electrical conductivity comparing with commercially purchased TiO2-containing composites especially at high temperatures. In the optical measurements, it was observed that there was an increase in the optical bandgap energy range values with GNPs reinforcement but a decrease in the reflectance values.
AtıfOpenAlex2İncele - MakaleYalnız künye2020Scopus SJRQ3Investigation of the Effect of Operating Conditions Change on Water Hammer in Hydroelectric Power Plants
Kahraman, Gökhan
Renewable energy sources do not harm the environment, and they contribute greatly to national economies. Hydraulic energy is the leading renewable energy source. Hydraulic energy is used more widely than other renewable energy sources around the world. This situation of hydraulic energy makes it important to solve the faults in hydraulic turbine-generator units. In this study, water hammer impacts have been investigated. This issue is important and can be dangerous in hydroelectric power plants. As a result of the research, the optimum sudden shutdown time of the adjusting wings in the snail is determined by considering the different operating conditions of a hydroelectric power plant. When the turbine-generator units are operated according to the specified instantaneous shutdown time, they will be protected against the impact of the water hammer pressure and the turbine shaft overspeed. Thus, they will be operated with less risk.
AtıfScopus9WoS8OpenAlex8İncele - MakaleYalnız künye2019Scopus SJRQ3Assessment of the mass attenuation coefficients of granite, basalt, andesite and tuff stones with the Geant4 model of a high-purity germanium detector
Aşkin, A.; Dal, M.
In this work, the radiation shielding properties of various natural stones, such as granite, basalt, andesite and tuff, were determined by using Monte-Carlo simulations performed with the Geant4 model of a high-purity germanium (HPGe) detector. Mass attenuation coefficients were calculated for γ-ray energies of 80.9, 140.5, 356.5, 661.6, 1173.2 and 1332.5 keV and for the sample thicknesses between 1 and 7 cm. The results of this study indicate that the stone samples have lower mass attenuation values varying in the range from - 28.8 % to - 3.7 % compared to lead. Among the measured stone samples, the mass attenuation values of tuff stone are closest to lead (above 661.6 keV).
AtıfScopus7WoS6OpenAlex8İncele - MakaleYalnız künye2019Scopus SJRQ2Physical, structural, optical, and radiation shielding properties of B2O3–Gd2O3–Y2O3 glass system
Al-Hadeethi, Y.; Sayyed, M.I.; Kaewkhao, J.; Askin, A.; Raffah, Bahaaudin M.; Mkawi, E.M.; Rajaramakrishna, R.
In the current paper, glass samples were prepared from the composition xGd2O3–(30-x)Y2O3–70B2O3 (where x = 5, 10, 15, 20 and 25 mol%) via the technique of melt-quenching. Various optical parameters and inter-atomic separation were evaluated for the fabricated samples. The results showed that the inter-substitution of Y2O3 content in replacement with Gd2O3 content in the glass matrix shows structural variation in the glass. The density increases from 3.5521 to 4.1613 g/cm3 with increase in Gd2O3 content that signifies the role of Gd2O3 being a glass modifier. The transmission spectra of the glass sample show more than 85% transmittance suggesting their superior transparency in the visible region. Also, several important shielding parameters of the prepared glass system have been computationally determined via the Geant4 model and the results were compared with Phy-X/PDS database software. The results revealed that the mass attenuation factor (µ/ρ) obtained by utilizing the two different toolkits are in agreement. The transmission fraction and the half value layer parameters of the glass system indicate that the glass sample with higher Gd concentration provides a better gamma blocking ability thanks to the high atomic number of Gd.
AtıfScopus31OpenAlex29İncele - MakaleYalnız künye2019Scopus SJRQ2The effect of a glyphosate-based herbicide on acetylcholinesterase (AChE) activity, oxidative stress, and antioxidant status in freshwater amphipod: Gammarus pulex (Crustacean)
Pala, Ayşegül
This study had determined the effect of glyphosate-based herbicide (GBH) on acetylcholinesterase (AChE) enzyme activity, oxidative stress, and antioxidant status in Gammarus pulex. Firstly, the 96-h LC50 value of glyphosate on G. pulex was determined and calculated as 403 μg/L. Subsequently, the organisms were exposed to sub-lethal concentrations (10, 20, and 40 μg/L) of the determined GHB for 24 and 96 h. The samples were taken from control and GBH-treated groups at 24 and 96 h of study and analysed to determine the malondialdehyde (MDA) and reduced glutathione (GSH) levels, the AChE, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) enzyme activities. In the G. pulex exposed to GBH for 24 and 96 h, the MDA level increased significantly (p < 0.05). The GSH level, the AChE, the CAT, and the GPx activities decreased compared with the control group (p < 0.05). G. pulex exposure to GBH for 24 h showed a temporary reduction in the SOD. GBH exposure led to oxidative stress in the G. pulex as well as affected the cholinergic system of the organism. These results indicated that the parameters measured may be important indicators of herbicide contamination in G. pulex.
AtıfScopus33WoS31OpenAlex35İncele - MakaleAçık Erişim2019Scopus SJRQ2Using Box–Behnken design approach to investigate benzo[a]anthracene formation in smoked cattle meat samples and its’ risk assessment
Kaplan Ince, Olcay; Ince, Muharrem
In present study, a novel approach was selected for benzo[a]anthracene determination from smoked cattle meat samples using solid phase extraction under various experimental conditions. To optimize experimental variables, a three factor, three-level Box–Behnken experimental design combining with response surface methodology and quadratic programming were employed to prevent excessive amount of benzo[a]anthracene formation in smoked meat based on different experimental parameters. The influence of some important process parameters including cooking time (10–30 min), fat ratio (5–25%) and distance to the cooking source (5–25 cm), which significantly affected the formation efficiency of benzo[a]anthracene were optimized. The analysis of variance was conducted for specifying the interactions of independent variables. The independent and the dependent variables interactions were investigated. The quadratic regression model and the response surface contour plots were used to determine optimum values for the selected variables. The results of study revealed that optimum cooking time of smoked cattle meat was determined as 24.9 min, fat ratio 7.9% and the distance to the cooking source 21.8 cm. Under optimum conditions, minimum benzo[a]anthracene was formed in meat and its amount was determined using high performance liquid chromatography-mass spectrophotometer as qualitative and quantitative. The limit of detection and limit of quantitation values were calculated as 0.4 µg kg −1 and 1.1 µg kg −1 , respectively.
AtıfScopus4WoS4OpenAlex8İncele - MakaleYalnız künye2019Scopus SJRQ2Evaluation of health risks from exposure to arsenic and heavy metals through consumption of ten fish species
Varol, Memet; Kaya, Gülderen Kurt; Sünbül, Muhammet Raşit
In this study, the levels of 11 heavy metal(loid)s (HMs) were determined in ten different fish species (wild, farmed, freshwater, and marine) frequently consumed in Turkey and compared with the maximum permissible limits (MPLs) established by international standards. Also, human health risks for the consumers were assessed. Among 11 HMs, only Al and Cr levels did not show significant differences among fish species. The highest concentrations of As were found in red mullet, which is a demersal fish. The average concentrations of Cd, Cr, Cu, and Pb in all fish species were below the MPLs, whereas those of Zn in European anchovy and Mediterranean horse mackerel, and that of inorganic As in red mullet exceeded the MPLs. The highest and lowest toxic metal contents (Al, As, Cd, and Pb) were recorded in red mullet and farmed rainbow trout, respectively. The estimated daily intakes of HMs in each fish species were very lower than their corresponding tolerable daily intakes, suggesting the daily intake of HMs through fish consumption would not pose health risks for the consumers. The target hazard quotient for individual HMs and hazard index for combined HMs in fish species were below 1, which indicated that non-carcinogenic health effects are not expected. The carcinogenic risk results revealed that there was a carcinogenic risk from exposure to inorganic As via the consumption of red mullet. Among all investigated fish species, rainbow trout and common carp were safer in terms of both non-carcinogenic and carcinogenic risks from exposure to HMs.
AtıfScopus72WoS63OpenAlex82İncele - MakaleAçık Erişim2018Scopus SJRQ3Extracellular Synthesis and Characterization of Gold Nanoparticles Using Mycobacterium sp. BRS2A-AR2 Isolated from the Aerial Roots of the Ghanaian Mangrove Plant, Rhizophora racemosa
Camas, Mustafa; Sazak Camas, Anil; Kyeremeh, Kwaku
Through the use of genomes that have undergone millions of years of evolution, marine Actinobacteria are known to have adapted to rapidly changing environmental pressures. The result is a huge chemical and biological diversity among marine Actinobacteria. It is gradually becoming a known fact that, marine Actinobacteria have the capability to produce nanoparticles which have reasonable sizes and structures with possible applications in biotechnology and pharmacology. Mycobacterium sp. BRS2A-AR2 was isolated from the aerial roots of the mangrove plant Rhizophora racemosa. The Mycobacterium was demonstrated for the first time ever to produce AuNPs with sizes that range between 5 and 55 nm. The highest level absorbance of the biosynthesized AuNPs was typical for actinobacterial strains (2.881 at 545 nm). The polydispersity index was measured as 0.207 in DLS and the zeta potential was negatively charged (− 28.3 mV). Significant vibration stretches were seen at 3314, 2358, 1635 and 667 cm−1 in FT-IR spectra. This demonstrated the possible use of small aliphatic compounds containing –COOH, –OH, –Cl and –NH2 functional groups in the stabilization of the AuNPs. The effect of the biosynthesized AuNPs on HUVEC and HeLA cell lines was measured at 48 h. IC50 values were determined at 3500 µg/ml concentration for HUVEC and HeLA cell lines at 45.25 and 53.41% respectively.
AtıfScopus66WoS35OpenAlex58İncele - MakaleAçık Erişim2018Scopus SJRQ3Optical solitons and other solutions to the conformable space–time fractional complex Ginzburg–Landau equation under Kerr law nonlinearity
Sulaiman, Tukur Abdulkadir; Baskonus, Haci Mehmet; Bulut, Hasan
This study reveals the dark, bright, combined dark–bright, singular, combined singular optical solitons and singular periodic solutions to the conformable space–time fractional complex Ginzburg–Landau equation. We reach such solutions via the powerful extended sinh-Gordon equation expansion method (ShGEEM). Constraint conditions that guarantee the existence of valid solitary wave solutions are given. Under suitable choice of the parameter values, interesting three-dimensional graphs of some of the obtained solutions are plotted.
AtıfScopus37İncele - DergiInternational Journal of Earth Sciences
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- DergiBrazilian Journal of Chemical Engineering
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