Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Gul, Muhammet(74)
- Akkurt, Nevzat(39)
- Celik, Erkan(35)
- Serdar, Osman(35)
- Güler, Ömer(33)
- Kutlu, Banu(32)
- Paksoy, Mehmet Yavuz(32)
- Yucesan, Melih(31)
- Tekin, H.O.(30)
- Yildirim, Numan(30)
- Yildirim, Nuran Cikcikoglu(30)
- ALMisned, Ghada(28)
- Mete, Suleyman(26)
- Danabas, Durali(20)
- Ince, Muharrem(20)
- Serin, Faruk(20)
- Ates, Mehmet(19)
- Can, Erkan(19)
- Onat, Onur(18)
- Benzer, Fulya(17)
- Kocabaş, Mehmet(17)
- Tanyol, Mehtap(17)
- Kizak, Volkan(16)
- Alataş, Mevlüt(15)
- Aydin, Rahmi(15)
- Kahraman, Gökhan(15)
- Kilic, G.(15)
- Polat, Alper(15)
- Susam, Selim Orhun(15)
- Xu, Qian(15)
- Aslan, Naim(14)
- Guler, Omer(14)
- Gürler, Nedim(14)
- Karatay, Gülnaz(14)
- Utku, Anıl(14)
- Yildirim, N. C.(14)
- Özkul, İskender(14)
- Demirol, Ferhat(13)
- Erguven, Gokhan Onder(13)
- Firat, Erhan(13)
Yayınlar
- MakaleYalnız künye2020Scopus SJRQ2Assessment of impact of α-Fe2O3 and γ-Fe2O3 nanoparticles on phytoplankton species Selenastrum capricornutum and Nannochloropsis oculata
Ates, Mehmet; Cimen, Isil C. C.; Unal, Ilkay; Kutlu, Banu; Ertit Tastan, Burcu; Danabas, Durali; Aksu, Onder; Arslan, Zikri
In this study, the impact of alpha-iron oxide (α-Fe2O3, 20-40 nm) and gamma iron oxide (γ-Fe2O3, 20-40 nm) nanoparticles (NPs) on phytoplankton species Selenastrum capricornutum and Nannochloropsis oculata was investigated Characterizations of the NPs were systematically carried out by TEM, dynamic light scattering, zeta potential, X-ray diffraction, SEM, and Fourier transformation infrared spectroscopy. Acute toxicity was tested between 0.2 and 50 mg/L for each NP for a period of 72 hours exposure. γ-Fe2O3 NP inhibited development of N oculata at the rate of 54% in 0.2 mg/L group with a high mortality rate of up to 82%. α-Fe2O3 NPs were less toxic that induced 97% mortality on N oculata at 10 mg/L suspensions. In contrast, α-Fe2O3 NP inhibited growth of S capricornutum strongly (73%) in 0.2 mg/L group. γ-Fe2O3 NPs showed similar growth inhibition (72%) on S capricornutum in 10 mg/L suspensions. Despite the differential effects, the results indicated acute toxicity of α-Fe2O3 and γ-Fe2O3 NPs on N oculata and S capricornutum.
AtıfScopus27WoS20OpenAlex25
İncele - Kitap BölümüYalnız künye2020NARX neural networks model for forecasting daily patient arrivals in the Emergency Department
Yucesan, Melih; Mete, Suleyman; Serin, Faruk; Celik, Erkan; Gul, Muhammet
Regarding measuring of service quality at the emergency departments (ED), essential parameters are length of stay (LOS) and waiting times. Patient arrivals, which is related to LOS and waiting times, is hard to forecast and is affected by many parameters. Therefore, authors employed a Nonlinear Autoregressive Exogenous (NARX) model for forecasting of ED arrivals. NARX models are used extensively in many applications that show non-linear and dynamic behavior, but as far as authors know, the NARX method has not yet been used in the forecast of ED arrivals before. In this study, calendar and climatic variables are defined as input parameters. Patient Arrivals is defined as output parameter. A commercial software, MATLAB, was used to train and test the data set. To find the best network architecture Levenberg- Marquardt (LM) and Bayesian Regularization (BR) algorithms, different lags, and number of neurons were tested. R-squared and mean square error (MSE) are used to evaluate the accuracy of the tested networks.
AtıfScopus2OpenAlex4İncele - BildiriYalnız künye2020Performance Evaluation of Different Window Functions for Audio Fingerprint Based Audio Search Algorithm
Uyanik, Hakan; Koseoglu, Murat
Window functions are structures that are frequently used to increase the quality of the transformation when processing the signal in the time-frequency domain, especially when creating the spectrogram of the signal. In calculations for frequency information, Fourier transforms of short-time samples of the signal are transformed into spectrogram data with the help of window functions, and then operations are performed by using these data. In this study, the performance of three different window functions, which are used in obtaining spectrogram data in the algorithm developed for audio fingerprint-based audio recognition, have been tested under different artificial noise conditions. The results of these three different window functions were compared graphically, and a truth table was obtained based on the analyzed database. As a result of the simulations carried out in MATLAB, it has been observed that the hanning window function gives better spectral results for different noise levels, and accordingly it produces better matching results compared to the other two window functions as reported in former studies on different applications. In addition, some improvements about window length have been added into algorithm to obtain better results.
AtıfScopus12OpenAlex10İncele - MakaleYalnız künye2020Scopus SJRQ2Assessment of Oxidative Stress on Artemia salina and Daphnia magna After Exposure to Zn and ZnO Nanoparticles
Ates, Mehmet; Danabas, Durali; Ertit Tastan, Burcu; Unal, Ilkay; Cicek Cimen, Isil Canan; Aksu, Onder; Kutlu, Banu; Arslan, Zikri
In this study, the effect of zinc nanoparticles (Zn NPs) and zinc oxide nanoparticles (ZnO NPs) on Artemia salina and Daphnia magna, the primary consumer organisms were investigated. In this sense, investigation of trophic transfer and ecological sustainability potentials among living things, such as fish and crustaceans that are at the top of the food chain were also aimed. Zn NPs in the size of 40–60 nm and 80–100 nm and ZnO NPs (10–30 nm) were administered to A. salina and D. manga (respectively in total 105000 and 14000 individuals) in seven groups (Control, 0.2, 1, 5, 10, 25 ve 50 ppm) with three repetitions for a period of 72 h. Intensive and possible misuse of nanoscale materials is one of the biggest threats to the environment and all living things worldwide. Therefore, the control mechanisms for the use of NPs need to be established.
AtıfScopus29WoS19OpenAlex32İncele - MakaleYalnız künye2020Scopus SJRQ1Gamma and neutron shielding characterizations of the Ag2O–V2O5–MoO3–TeO2 quaternary tellurite glass system with the Geant4 simulation toolkit and Phy-X software
Aşkın, A.
Gamma and neutron shielding potential of the newly developed xAg2O-(35-x)[0.5V2O5-0.5MoO3]-65TeO2 (x = 0, 5, 10, 15, 20 and 25 mol%) quaternary tellurite glass system were investigated computationally by means of Geant4 Monte Carlo simulations and Phy-X software. Gamma ray shielding capabilities were studied via the mass attenuation coefficient (μm), transmission fractions (T), effective atomic number (Zeff), half value layer (HVL) and mean free path (MFP) parameters and for the photon energies of 0.284, 0.356, 0.511, 0.662, 1.173 and 1.330 MeV. Fast neutron removal cross-section (∑R) parameter of the glasses was calculated to assess the neutron shielding capabilities. The results of this study revealed that tellurite glass containing 25% moles of Ag2O has highest μm and Zeff and lowest T, HVL and MFP values due to the high atomic number of Ag. In this study it was also seen that the ∑R of the investigated glass system increases with the increase of Ag2O fraction and ∑R values of the studied glasses are higher than barite added concrete and close to the ∑R of the PbO added borate glasses.
AtıfScopus36WoS35OpenAlex37İncele - MakaleYalnız künye2020Scopus SJRQ2Synthesis and Characterization of Disodium Hydrogen Phosphate Dodecahydrate-Lauric-Palmitic Acid Used for Indoor Energy Storage Floor Units
Xu, Qian; Akkurt, Nevzat; Zou, Zhenwei; Liu, Yang; Feng, Junxiao; Yu, Chuqiao; Ding, Chong; Xiong, Yaxuan; Zhou, Jingzhi; Zang, Yong
Organic and inorganic phase change materials (PCMs) are considered potential materials for thermal energy storage (TES) with different phase change characteristics. In this study, a novel organic-inorganic composite phase change material (PCM) called disodium hydrogen phosphate dodecahydrate-lauric-palmitic acid (D-LA-PACM) was prepared. Expanded graphite (EG) was selected as the support material, and the novel organic-inorganic form-stable PCM called D-LA-PAPCM/EG was prepared using the vacuum adsorption method. Differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, leakage testing, melting and solidification cycle testing, thermal conductivity testing, scanning electron microscopy observation of the micromorphology, and other characterization methods were used to study the micro structure and morphology, thermal physical parameters, thermal conductivity, stability of the PCMs, and the comprehensive material properties of D-LA-PAPCM under the composite action of EG. Results indicated that the melting and freezing temperatures and latent heats of D-LA-PAPCM/EG were measured to be 31.6°C and 34.3°C and 142.9 and 142.8 J/g, respectively. Although some of the lauric-palmitic acid (LA-PA) and disodium hydrogen phosphate dodecahydrate (DHPD) separated in the multiple porous structures of EG after 1000 cycles, they could still absorb and release latent heats independently, with D-LA-PAPCM/EG still exhibiting good thermal stability. The thermal conductivity of D-LA-PAPCM/EG was 1.361 W/(mK). Therefore, the material and thermal properties of the prepared D-LA-PAPCM/EG indicate that it could be well used as a feasible material for energy-saving phase change floor units in indoor TES systems.
AtıfScopus18OpenAlex18İncele - MakaleYalnız künye2020Scopus SJRQ3The anesthetic effects of 2-phenoxyethanol on Munzur trout fingerlings (Salmo munzuricus Turan et al., 2017) at different temperatures
Akgul, E.; Can, E.
In this study, the anesthetic effects of 2-phenoxyethanol (2-PE, with %99 purity, BASF, Germany) on Munzur trout (Salmo munzuricus., a native species) originated from Munzur stream have been studied. 300 fish with the average weight of 4.42±0.62 g and length of 8.10±0.60 cm were used. To determine the anesthetic effects of various concentrations of 2-PE on Munzur trout fingerlings, the experiments were performed in two different temperatures (13 ºC and 18ºC) and five different concentrations (0.1, 0.2, 0.3, 0.4 and 0.5 ml L-1). 2-PE was used in this study as an anesthetic agent. In the anesthetic processing we practiced in all concentrations, except for 0.1 ml L-1 of 2-PE, loss of reflex (S5) was determined between 68 sec and 276 sec, and total behavioral recovery (R3) was determined between 58 sec and 208 sec. Induction times of anesthesia varied with anesthetic concentrations, decreasing with the increases of 2-PE concentrations. On the other hand, recovery times increased with decreasing of anesthetic concentrations. The lowest effective dose was determined as 0.3 ml L-1 at the temperatures 13 ºC and 18ºC. In this study, first time optimum anesthetic doses of 2-PE were determined for fingerling specimens of Salmo munzuricus which is endemic to Munzur stream and has an importance for aquaculture.
AtıfScopus4WoS3OpenAlex1İncele - MakaleYalnız künye2020Scopus SJRQ1Assesment of the gamma and neutron shielding capabilities of the boro-tellurite glass quaternary containing heavy metal oxide using Geant4 and Phy-X/PSD database
Aşkın, A.
This survey was conducted to reveal the gamma and neutron stopping performance of the 30PbO–10ZnO—(60-x)TeO2—xB2O3 (x = 0, 10, 20, 30, 50% mole) glass quaternary. Gamma and neutron attenuation parameters including the linear attenuation coefficient (μ), transmission fraction (TF), half value layer (HVL), mean free path (MFP), effective atomic number (Zeff), exposure buildup factor (EBF) and fast neutron removal cross-section (∑R) were determined computationally using the Geant4 and Phy-X/PSD database tools and for photon energies ranging between 0.284 MeV and 2.510 MeV. It was found that increasing the B2O3 content from 0% to 50% mole and correspondingly decreasing the TeO2 content from 60% to 10% mole results in a degradation of μ by 18.2% and of Zeff by 28.6% at 0.284 MeV. Due to this decrease in μ and Zeff, the values of TF and HVL increased by 37.3% and 22.4% respectively. In the present study it was also observed that the density (ρ) of glass quaternary decreased with the decreasing content of TeO2, and that the density of glass has a remarkable effect on the photon attenuation characteristics. The Degradation of μ, Zeff, ρ and the increase of TF and HVL proves that the photon attenuation ability of the glasses investigated worsens with decreasing content of TeO2, as Tellurium's atomic number and atomic mass are high compared to those of boron. While the decrease of TeO2 weakens the photon attenuation performance, it was found that fast neutron attenuation increases as ∑R increases from 0.108 to 0.116 for the glass specimens containing 60% and 10% mole of TeO2 respectively.
AtıfScopus31WoS31OpenAlex33İncele - MakaleYalnız künye2020Scopus SJRQ1Structural, elastic, optical and γ-ray shielding behavior of Dy3+ ions doped heavy metal incorporated borate glasses
Divina, R.; Sathiyapriya, G.; Marimuthu, K.; Askin, A.; Sayyed, M.I.
The effect of modifier ions in different basis have been analyzed through a new series of heavy metals incorporated borate based glasses 39H3BO3+30PbO+20MO+10Bi2O3 +1Dy2O3 (where M=Ca,Sr,Ba,Na and K) which are synthesized following melt quenching technique for radiation screening applications. The potentiality of glasses to withstand the penetration of fast moving neutrons is checked by various studies. Functional groups are identified through different stretching and bending modes of vibrations within the glass membrane through FTIR spectral analysis. In addition to that, other structural properties like Boron-Boron distance (dB−B), molar volume of oxygen (Vo), Oxygen Packing Density (OPD), optical basicity (Λth) and Bond density (nb) are calculated theoretically. The bonding nature (β) and nephelauxetic ratio (δ) values reveals that the glasses possess more of ionic linkages. The high density value exhibited by the Bismuth lead borate glasses indicates their capability to act as a good shielding material in reactors emitting hazardous radiation. Different moduli of elasticity (E, K, G, σ) values for the present glasses are calculated and the results reveal the enhancement in shielding performances when compared to other existing glasses and a comparative study is made on it. Optical studies are carried out and the absorption of Dy3+ions to different energy levels is observed and optical band gap (Eopt) values of the synthesized glasses are calculated along with the Urbach energy (ΔE) values. Radiation shielding properties of the produced glasses were investigated in terms of the mass attenuation coefficients (µm), transmission fraction (T), half value layer (HVL) and effective atomic number (Zeff) parameters. The results attained in the shielding study indicated that glass specimen with M = Ba exhibits enhanced shielding behavior as Ba owns high atomic number (Z) compared to other elements. Glass specimen with M = Na shows the poorest shielding characteristics due to the low Z of Na.
AtıfScopus117OpenAlex107İncele - MakaleYalnız künye2020Scopus SJRQ2An Evaluation Research About Effects of Characterized Cadmium Selenide (CdSe) and Lead Selenide (PbSe) Quantum Dots on Brine Shrimp (Artemia salina)
Ates, Mehmet; Tastan, Burcu Ertit; Danabas, Durali; Cicek-Cimen, Isil Canan; Aksu, Onder; Kutlu, Banu; Unal, Ilkay; Arslan, Zikri
Quantum dots (QDs), such as cadmium selenide (CdSe) and lead selenide (PbSe) exhibit excellent optical, magnetic and chemical properties due to their extremely size (ca. 1–10 nm) and are attractive semiconductor nanomaterials for optical studies and energy storage. In this study, aqueous synthesis of CdSe and PbSe QDs in a size range of 2–10 nm was described. Synthesized QDs were characterized using SEM and TEM, DLS, zeta potential, FTIR, EDX and XRD. Highest accumulation (72.5 ± 5.8 mg L−1) of PbSe QDs occurred at 10 ppm suspensions. In general accumulation increased up to 48 h exposure then fluctuate tended to decline. For CdSe QDs, accumulation tended to decrease for 72 h exposure except that for 5 ppm groups. For the elimination period, in general, the elimination levels of PbSe and CdSe QDs from exposed individuals decreased (p < 0.05) even it has some fluctuate.
AtıfScopus6WoS4OpenAlex5İncele - MakaleYalnız künye2020Scopus SJRQ4Spermatologic characteristics and sperm motility alterations caused by short-term copper exposure in Brook Trout Salvelinus fontinalis
Kutluyer, Filiz; Kocabaş, Mehmet; Başçınar, Nadir
Spermatozoa movement in many aquatic animals with external fertilization is directly related to the external aqueous environment. In particular, environmental toxic metals can cause harmful effects and impair sperm cell functions. The high concentrations of copper (Cu) may be harmful for aquatic animals, while low levels are required for metabolic interactions. Herein, we investigated the effect of different copper concentration [0 mg L−1 (Control),.5 mg L−1, 1 mg L–1, and 2 mg L−1] on spermatozoa of brook trout Salvelinus fontinalis. Motility and survival of sperm cells were assessed. Our results indicated that Cu exposure caused to an evident decrease in motility and longevity of spermatozoa with increasing concentrations (p <.05). Overall, we showed that Cu exposure can impair sperm motility of S. fontinalis. Our study suggested that sperm motility has the potential to be a sensitive bioindicator of freshwater environmental pollution.
AtıfScopus3WoS3OpenAlex3İncele - MakaleYalnız künye2020Scopus SJRQ2A novel proximity graph: Circular neighborhood cell graph for histopathological tissue image analyzing
Serin, Faruk; Erturkler, Metin
The cell is the smallest unit of living beings, which has structural and functional properties. Almost all cell behaviors are regulated by various intracellular reactions initiated by the signaling. The signaling and the distance between cells influence each other. Thus, cell-location-based modeling and analyzing of histopathological tissues provide important information to the expert. In literature, methods such as distance-based threshold, K-Nearest Neighbor, Voronoi graphs, Delaunay triangulation, and colored graph have been used. However, circular neighborhood relationships of cells have not been considered by any CAD system so far despite of its crucial impact. Thus, we developed the circular neighborhood cell-graph. Histopathological images of liver were classified by using features extracted from T-Distance, K-Nearest Neighbor, Voronoi, Delaunay, and the proposed cell-graph. Then, the classification performances of the methods were compared. Experimental results show that liver tissue images can be classified with accuracy of 95.7% by using the features provided by the proposed cell-graph model.
AtıfScopus1WoS1OpenAlex1İncele - MakaleYalnız künye2020Scopus SJRQ4Occurrence of the freshwater jellyfish Craspedacusta sowerbii Lankester, 1800 from Uzunçayır dam lake (Tunceli), Turkey
Kutlu, Banu
In this study, Craspedacusta sowerbii Lankester, 1880 a jellyfish species belonging to freshwater hydrozoan group, was reported for the first time in the field study carried out at Uzunçayır dam lake in Tunceli province on 15 September 2018. The plankton samples were obtained from two different regions of the lake using UNESCO WP2 plankton net with mesh size of 200 µm. C. sowerbii, one of the fresh water hydrozoans obtained from plankton samples, is rarely observed in man-made lakes, ponds, and reservoirs, and has not been observed earlier in the Uzunçayır dam lake. The C. sowerbii might have placed in the lake through some fishing activities which were conducted from 2010 to 2017 and/or through some sport equipment's (i.e. boat, jetski, were brought to the region for recreational purposes).
AtıfScopus2İncele - MakaleYalnız künye2020Scopus SJRQ4Biochemical responses of some (Helianthus annuus L.) cultivars to the interaction effects of biodegradable polymer and salt stress
Akbulut, Gulcin Beker; Torgut, Gulben
Salt stress is one of the most important environmental factor limiting plant growth and causing serious agricultural problems in the world. Biodegradable poly(ethylene oxide)-co-(ε-caprolactone) poly(EO-co-ε-CL) copolymer synthesized by ring-opening polymerization (ROP) have been used to reduce this negative effect. For the characterization of this copolymer, the Fourier Transform Infrared (FT-IR), Proton Nuclear Magnetic Resonance (1H-NMR), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) techniques were used. To investigate the impact of copolymer and salt (200 mM NaCl) singly and in combination, on two different sunflowers (Helianthus annuus L. cv. 'Düet' and Helianthus annuus L. cv. 'Meteor') a series of experiments were established. In the seedlings grown for 21 days, differences in some metabolic parameters such as chlorophyll-a (Chl-a), chlorophyll-b (Chl-b), carotenoids (Car), total chlorophyll (Chl), total carbohydrate content, and malondialdehyde (MDA) content were examined. According to the result of our study, after the application of NaCl and poly(EO-co-ε-CL), significant changes were observed in the studied biochemical parameters. It was observed that the copolymer in both species had a healing effect against salt stress. Application of 200 mM NaCl caused an increase in MDA of both genotype, particularly in 'Meteor'. Higher Chl-a, Chl-b, total Chl, and Car contents were observed in 'Meteor' as compared to that in 'Düet' under saline conditions. Total carbohydrate content decreased with increasing salt stress in both cultivars.
AtıfScopus1İncele - Kitap BölümüYalnız künye2020A fuzzy decision-making model for the key performance indicators of hospital service quality evaluation
Yucesan, Melih; Mete, Suleyman; Gul, Muhammet; Celik, Erkan
One of the major concerns of the healthcare industry throughout the world is to provide better hospital service quality. Management and delivery of hospital healthcare services are achieved in a competitive environment in Turkey. For this reason, to make better decisions, the services provided by the public and private hospitals should be monitored and evaluated according to the viewpoint of medical stakeholders. This chapter presents a cause-and-effect, decision-making model in evaluating hospital service quality criteria. Since the decision-making process involves the vagueness of human judgments, a combination of fuzzy sets and decisionmaking trial and evaluation laboratory (DEMATEL) is used. Results of the study demonstrate that medical equipment level of the hospital, the attitude of nurses and medical staff to patients, pharmacists' advice on medicine preservation, medical staff with professional abilities, outpatient waiting time for medical treatment, and number and quality of the bathrooms available have more impact on the entire hospital service quality. In conclusion, the proposed approach will contribute to better providing of healthcare services at a higher quality level.
AtıfScopus5OpenAlex5İncele - MakaleYalnız künye2020Scopus SJRQ1Failures of masonry dwelling triggered by East Anatolian Fault earthquakes in Turkey
Yön, Burak; Onat, Onur; Emin Öncü, Mehmet; Karaşi̇n, Abdulhalim
Turkey is located on active fault zones such as the East Anatolian Fault (EAF), the North Anatolian Fault (NAF) and the Anatolian-Aegean Subduction Zone (AASZ). Ground seismicity activities of the NAF zone are relatively active compared with other faults. Eleven high-intensity earthquakes have been produced on this fault zone since 1939. Whereas the EAF zone was relatively quiescent in the last century, on the basis of historical records, destructive seismic activities occurred on the EAF zone in the last two decades. In this study, the rupture reason of faults, updated active fault data, and seismic maps are presented briefly. Moreover, failure reasons and failure mechanism of conventional masonry structures damaged from seismic ground motions on the EAF zone are evaluated in detail. Possible solutions are suggested on the basis of seismic codes. For this purpose, EAF-sourced earthquakes, i.e. 2003 Bingöl, 2010 Kovancılar (Elazığ), 2011 Maden (Elazığ), 2011 Tabanlı (Van) and Edremit (Van) hit in last two decades on this fault are investigated. Failures of conventional masonry buildings triggered from these earthquakes are assessed. Statistical evaluation, damage of earthquakes and failure pattern are deeply investigated and revealed. Eventually, one of the most significant reasons of severe damage or collapse to masonry structures due to this seismicity is the inability to construct the structures according to the requirements of seismic codes.
AtıfScopus41WoS39OpenAlex46İncele - MakaleYalnız künye2020Scopus SJRQ3Application of Local Hard Fillet Weld to Repair Damage Caused by Cavitation in Hydroelectric Power Plant
Kahraman, Gökhan; Taşgin, Yahya
Hydroelectric power plants come into prominence worldwide day by day due to their low operating and maintenance costs, environment friendly structure and their use as renewable energy sources. In order to obtain maximum energy from such an important energy source, it is necessary to reduce downtime due to failures. One of the most important failures of hydroelectric power plants is the damage caused to the turbine wheel by cavitation. In this study, a sample with the same material as the turbine wheels of the hydroelectric power plants is provided. The effects of the hard fillet weld on the turbine wheel, which we have applied locally to this material, have been investigated both metallographically and physically. As a result of the research, it is observed that the main material and hard fillet weld are mostly compatible. The damages of the turbine wheel of the hydroelectric power plant have been repaired by applying the same method to the turbine wheel damaged by the cavitation. After 10,000 h of operation, the turbine wheel is inspected again. As a result, it has been determined that the hard fillet weld applied to the turbine wheel surface is resistant to the harmful effects of cavitation.
AtıfScopus2WoS2OpenAlex2İncele - MakaleYalnız künye2020Scopus SJRQ2Investigation on Microbial Biodeterioration of the Stone Monuments in Yildiz Technical University—Yildiz Campus—Istanbul—Turkey
Özdemir, Aysun; Erguven, Gokhan Onder; Adar, Elanur; Nuhoglu, Yasar
The stone samples of historical monuments around Yıldız Technical University Besiktas Campus were investigated using DNA extraction-PCR-DGGE methods, scanning electron microscopy (SEM), XRF, and other analytical methods to assess stone decay over the centuries. Microbial diversity was examined by classical cultivation and modern diagnostic methods besides modern analysis techniques. The number of the microorganisms in per gram of stone samples was calculated by microbial culture methods. SEM analysis showed that stone surfaces have too many pores, decaying pieces and microbial colony. It is put forth by XRF analysis that stone materials have some elements serving the growth of microorganisms. It was concluded that there is a close connection the stone structure and microbial growth, most likely mineralogical composition, hardness and porosity of stone. Cyanobacterial microorganisms lived on stone surfaces were also determined using denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA gene fragments. It was revealed DNA-based molecular analysis of 16S rRNA that 23 bacterial/Cyanobacterial clones were inhabited to stone materials.
AtıfScopus10WoS10OpenAlex11İncele - MakaleYayıncıda açık erişim2020Scopus SJRQ4Assessment of elemental content, antioxidant activity, and total phenolic content of vitis sylvestris gmelin
Ayhan, Nagihan Karaaslan
In this study, we determined the Cu, Fe, Mn, and Zn contents of Vitis sylvestris Gmelin using flame atomic absorption spectrometry (FAAS), and examined the antioxidant properties of Vitis sylvestris Gmelin using radical scavenging capacities and total phenolic content tests. We found the average elemental contents; Cu, Fe, Mn, and Zn as 1.506 ± 0.042 mg/kg, 0.796 ± 0.020 mg/kg, 2.333 ± 0.033 mg/kg, and 3.191 ± 0.262 mg/kg, respectively. When we examined the antioxidant activity tests applied to different extracts, we determined the highest extraction yield with the methanol extract. DPPH radical scavenging activity, ABTS radical scavenging activity, and total phenolic content values in methanol extract were determined to be respectively 3.957 ± 0.146 mg TEAC/g fw, 9.062 ± 0.273 mg TEAC/g fw, and 2.365 ± 0.028 mg GAE/g fw. When we evaluated the antioxidant activity and total phenolic content results for all extracts statistically, we determined that there was generally a statistically significant difference between each extract (p < 0.01). Vitis sylvestris Gmelin has high antioxidant content when considering the data obtained. Also, we determined that it is an effective candidate in the protection against reactive oxygen species.
AtıfScopus2OpenAlex3
İncele - MakaleYalnız künye2020Scopus SJRQ2The effect of graphene oxide on structural, opto-electrical and thermal properties of manganese sillenite (Bi12MnO20) nano-powders
Aydin, C.; Taskin, M.; Aydin, H.
In this study, manganese sillenite nano-powders were produced by hydrothermal method by adding graphene oxide in different mass amounts. Structural, morphological, thermal, optical and electrical properties of the obtained undoped and graphene-oxide-doped samples were investigated. XRD results showed that the produced samples had nano-sizes and the crystal sizes changed with the addition of graphene oxide. SEM and TEM images showed that the microstructures of the samples were nano-sized and composed of randomly oriented particles without orientation relationship between them. From FT-IR spectra of the samples, chemical properties and bond structures were determined. With the help of thermal analysis measurements, reactions in the sample structures at increasing temperatures, reaction temperatures, reaction energies and total mass losses were determined. The forbidden energy ranges of the samples decreased at significant rates with the addition of graphene oxide. By checking the P–E hysteresis cycles, the samples are understood to show ferroelectric properties. Dielectric measurements and temperature-dependent electrical conductivity measurements of the produced nano-powders confirmed that the samples exhibited semiconductor behaviour. The obtained results showed that manganese sillenites can be synthesised by low-temperature hydrothermal method and physical, chemical and thermal properties can be controlled by adding different amounts of graphene oxide for use in electronic and energy applications.
AtıfScopus6WoS6OpenAlex6İncele