Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Gul, Muhammet(85)
- Serdar, Osman(72)
- Güler, Ömer(68)
- Akkurt, Nevzat(61)
- Baskonus, Haci Mehmet(54)
- Alataş, Mevlüt(53)
- Paksoy, Mehmet Yavuz(53)
- Yucesan, Melih(53)
- Bulut, Hasan(51)
- Tekin, H.O.(51)
- ALMisned, Ghada(48)
- Yildirim, Numan(48)
- Benzer, Fulya(47)
- Kocabaş, Mehmet(45)
- Yildirim, Nuran Cikcikoglu(44)
- Kutlu, Banu(41)
- Ince, Muharrem(39)
- Zengin, Gokhan(39)
- Batan, Nevzat(37)
- Utku, Anıl(35)
- Celik, Erkan(33)
- Topal, Murat(32)
- Ezer, Tülay(31)
- Tanyol, Mehtap(31)
- Can, Erkan(30)
- Sulaiman, Tukur Abdulkadir(29)
- Aslan, Naim(28)
- Özkul, İskender(28)
- Aslan, Alper(27)
- Cakilcioglu, Ugur(27)
- Erguven, Gokhan Onder(27)
- Kutluyer, Filiz(27)
- Kök, Mediha(27)
- Ates, Mehmet(26)
- Erten, Fusun(26)
- Kahraman, Gökhan(26)
- Onat, Onur(26)
- Dal, Nursel Alp(25)
- Danabas, Durali(25)
- Say, Yakup(25)
Yayınlar
- MakaleYalnız künye2020Scopus SJRQ1Geochemical characteristics of the adakite-like Dodurga Pluton (Central Pontides, N Turkey): implications for Middle Triassic continental arc magmatism in southern Black Sea region
Çimen, Okay
The tracing of Triassic arc magmatism is much-debated for a long time along the Sakarya Composite Terrane in Turkey and the southern Black Sea region. The Dodurga Pluton is located in the Central Pontides (N Turkey), one of the most complicated regions around the Black Sea region, and represents the first documented middle Triassic continental arc in the region. This pluton comprises of dacite porphyry and granodiorite, and displays calc-alkaline signatures, which is in agreement with arc-related and I-type magmas. The PM-normalized multi element and CN-normalized REE patterns are akin to volcanic arc granites, and characterized by LILEs and LREEs enrichments relative to HFSEs and HREEs coupled with negative Nb anomalies, which confirm derivation in a subduction-related tectonic setting. Moreover, the major and trace element systematics of the samples including higher Sr/Y ratios (22.93–101.36) and lower Yb contents (0.31–1.30 ppm) are consistent with those from adakitic melts compared to classical arc magmas. Therefore, this pluton also represents the first middle Triassic adakite-like magmatic occurrence in Turkey. Overall petrographic and geochemical signatures reported here indicate that the Dodurga Pluton might have been derived from a heterogeneous source, mixed by melts from subducted oceanic slab and lower continental crust in an active continental margin. Based on the Tethyan evolution in the Anatolian realm, three geodynamic scenarios are possible for its formation, and it could have been formed as a result of northward or southward-subduction of the Paleotethys Ocean or northward-subduction of the northern branch of Neotethys Ocean during the middle Triassic.
AtıfScopus8WoS8OpenAlex4
İncele - MakaleAçık Erişim2020Scopus SJRQ1Evaluation of hospital disaster preparedness by a multi-criteria decision making approach: The case of Turkish hospitals
Ortiz-Barrios, Miguel; Gul, Muhammet; López-Meza, Pedro; Yucesan, Melih; Navarro-Jiménez, Eduardo
Considering the unexpected emergence of natural and man-made disasters over the world and Turkey, the importance of preparedness of hospitals, which are the first reference points for people to get healthcare services, becomes clear. Determining the level of disaster preparedness of hospitals is an important and necessary issue. This is because identifying hospitals with low level of preparedness is crucial for disaster preparedness planning. In this study, a hybrid fuzzy decision making model was proposed to evaluate the disaster preparedness of hospitals. This model was developed using fuzzy analytic hierarchy process (FAHP)-fuzzy decision making trial and evaluation laboratory (FDEMATEL)-technique for order preference by similarity to ideal solutions (TOPSIS) techniques and aimed to determine a ranking for hospital disaster preparedness. FAHP is used to determine weights of six main criteria (including hospital buildings, equipment, communication, transportation, personnel, flexibility) and a total of thirty-six sub-criteria regarding disaster preparedness. At the same time, FDEMATEL is applied to uncover the interdependence between criteria and sub-criteria. Finally, TOPSIS is used to obtain ranking of hospitals. To provide inputs for TOPSIS implementation, some key performance indicators are established and related data is gathered by the aid of experts from the assessed hospitals. A case study considering 4 hospitals from the Turkish healthcare sector was used to demonstrate the proposed approach. The results evidenced that Personnel is the most important factor (global weight = 0.280) when evaluating the hospital preparedness while Flexibility has the greatest prominence (c + r = 23.09).
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İncele - MakaleAçık Erişim2020Scopus SJRQ11D-CADCapsNet: One dimensional deep capsule networks for coronary artery disease detection using ECG signals
Butun, Ertan; Yildirim, Ozal; Talo, Muhammed; Tan, Ru-San; Rajendra Acharya, U.
Purpose: Cardiovascular disease (CVD) is a leading cause of death globally. Electrocardiogram (ECG), which records the electrical activity of the heart, has been used for the diagnosis of CVD. The automated and robust detection of CVD from ECG signals plays a significant role for early and accurate clinical diagnosis. The purpose of this study is to provide automated detection of coronary artery disease (CAD) from ECG signals using capsule networks (CapsNet). Methods: Deep learning-based approaches have become increasingly popular in computer aided diagnosis systems. Capsule networks are one of the new promising approaches in the field of deep learning. In this study, we used 1D version of CapsNet for the automated detection of coronary artery disease (CAD) on two second (95,300) and five second-long (38,120) ECG segments. These segments are obtained from 40 normal and 7 CAD subjects. In the experimental studies, 5-fold cross validation technique is employed to evaluate performance of the model. Results: The proposed model, which is named as 1D-CADCapsNet, yielded a promising 5-fold diagnosis accuracy of 99.44% and 98.62% for two- and five-second ECG signal groups, respectively. We have obtained the highest performance results using 2 s ECG segment than the state-of-art studies reported in the literature. Conclusions: 1D-CADCapsNet model automatically learns the pertinent representations from raw ECG data without using any hand-crafted technique and can be used as a fast and accurate diagnostic tool to help cardiologists.
AtıfScopus100OpenAlex96İncele - MakaleYalnız künye2020Scopus SJRQ2Analytical and finite element solutions of continuous contact problem in functionally graded layer
Kaya, Yusuf; Polat, Alper; Özşahin, Talat Şükrü
In this study, we solve the continuous contact problem of two layers with different material properties, loaded with two rigid flat blocks and resting on a rigid plane, by analytical and finite element methods. All surfaces are assumed to be frictionless. The upper layer is the functionally graded layer (FG), the height h1, the underlying layer is homogeneous, and the height is h2. It is assumed that the FG layer is isotropic and that the shear modulus and density change exponentially. The FG layer is loaded by means of two rigid flat blocks whose external loads are Q and P (per unit thickness in z direction). In the analytical solution of the problem, stress and displacement expressions are substituted in the boundary conditions and the problem is demoted to singular integral equations where the contact stresses are the unknown functions. These singular integral equations are solved numerically using the Gauss–Chebyshev integration formulas. Two-dimensional finite element analysis of the problem is performed using the ANSYS package program. The analyses are performed for different shear modulus ratios (μ2/μ-h1), distances between the blocks ((c − b)/h1) and inhomogeneity parameters (βh1). The contact stresses under the blocks, the normal stresses (σy) between interfaces of the FG layer and the homogeneous layer and between the homogeneous layer and rigid plane are also measured. In addition, the initial separation load and the initial separation distances (χcr, λcr) of the FG layer and homogeneous layer are determined. The results are presented comparatively as graphs and tables.
AtıfScopus18WoS19OpenAlex14İncele - MakaleYayıncıda açık erişim2020Scopus SJRQ2Phytoremediaton of priority substances (Pb and Ni) by Phragmites australis exposed to poultry slaughterhouse wastewater
Topal, Murat; Arslan Topal, E. Işıl
The aim of the work was to evaluate the ability of Phragmites australis to uptake lead and nickel from the stream taking the treated poultry slaughterhouse wastewater (PSW). Pb and Ni concentrations, which are the priority substances of the water frame directive, were detected separately at the root, stem and leaf of P. australis at 50 m and 100 m from the downstream of discharge point. The uptake of Pb and Ni by P. australis followed the order of root > leaf > stem. The Ni uptake was higher than Pb uptake in P. australis exposed to poultry wastewater. As a result, P. australis exposed to PSW were found to have the ability to uptake Pb and Ni. It has been determined that P. australis can be used for removal and phytoremediation of Pb and Ni metals from PSWs.
AtıfScopus13WoS12İncele - MakaleYalnız künye2020Scopus SJRQ1A manufacturing failure mode and effect analysis based on fuzzy and probabilistic risk analysis
Gul, Muhammet; Yucesan, Melih; Celik, Erkan
This study proposes an improved failure mode and effect analysis (FMEA) with fuzzy Bayesian Network (FBN) and fuzzy best-worst method (FBWM) to assess failures in plastic production. To eliminate the drawbacks of the classical risk priority number (RPN) computation of FMEA, this approach is developed. Unlike classical RPN, a new parameter hierarchy is constructed, and three sub-parameters are injected into the approach. These parameters are weighted by the aid of FBWM. Hereafter, a fuzzy rule-based system is constructed by incorporating Bayesian Network (BN). Also, a sensitivity analysis is performed to observe the final FMEA score changes in accordance with the change of subjective probability values. Finally, a comparative analysis with two approaches of classical FMEA and FBWM-based FMEA (without a fuzzy rule-based system incorporating BN) is fulfilled. The results of the study are strengthened with the experts’ opinions regarding the importance of failure modes for the final product and the whole system and supported them by experience feedback in the observed facility.
AtıfScopus68WoS59OpenAlex68İncele - MakaleYalnız künye2020Scopus SJRQ2The effect of graphene nano-sheet (GNS) weight percentage on mechanical and corrosion properties of AZ61 and AZ91 based magnesium matrix composites
Guler, Omer; Say, Yakup; Dikici, Burak
In this study, the effect of graphene nano-sheets (GNSs) on mechanical and corrosion properties of AZ61 and AZ91 based composites was investigated, detail. GNSs have been successfully produced by the liquid phase exfoliation (LPE) method and then, added AZ61 and AZ91 matrix with 01, 0.2, and 0.5 wt% GNSs for the production of the composites. The composite compacts were produced by powder metallurgy technique and sintered for 2 h at 500 °C under Ar atmosphere. The composite characterizations were carried out by scanning and transmission electron microscopes (SEM, TEM), electron dispersive spectroscope (EDS), Raman spectroscopy, and X-ray diffraction. The mechanical properties and corrosion behaviors of the composites have been compared with compression tests and potentiodynamic scanning (PDS) techniques, respectively. The results showed that the compressive strength of the composites increased with increasing GNS amount in both the AZ61 and AZ91 matrix alloys. The most susceptible composites to corrosion for both AZ61 and AZ91 matrix were observed in the 0.5 wt% GNS containing structures. However, there is a certain ratio of GNS in the Mg matrix to achieve good corrosion resistance.
AtıfScopus29WoS25OpenAlex33İncele - MakaleYalnız künye2020Scopus SJRQ1Linear, nonlinear optical and photon attenuation properties of La3+ doped tellurite glasses
Boukhris, Imed; Kebaili, Imen; Sayyed, M.I.; Askin, A.; Rammah, Y.S.
Linear and nonlinear optical features of La3+ doped tellurite glasses in the form 75TeO2–10ZnO –5Li2O –(10-x)Nb2O5 –xLa2O3: x = 0, 0.5, 1.0, 1.5, 2.0, and 2.5 in mol% (abbreviated as La0.0. La0.5, La1.0, La1.5, La2.0, and La2.5) were investigated. Also, the γ-photons attenuation parameters were tested utilizing Geant4 simulation code. Results revealed that the molar polarizability (αmolar) takes values from 8.685 × 10−24 to 7.933 × 10−24 cm3, while the molar refraction (Rmolar) changes from 21.886 to 20.219 (cm3/mol) for La0.0 to La2.5 glasses. The static dielectric constant (εstatic) varies from 6.368 to 5.191, whereas optical electronegativity (χ*) varies from 0.690 to 0.852 for La0.0-La2.5 glasses. Non-linear optical susceptibility (χ3) decreases from 5.675 × 10−12 to 2.109 × 10−12 (esu) with increment La2O3 content in the glasses, while non-linear refractive index (n2optical) decreases from 8.472 × 10−11 to 3.488 × 10−11 (esu). The radiation attenuation characteristics for the tested glasses were investigated with the help of Geant4 code. The mass attenuation coefficient (μm) was simulated between 0.284 and 2.506 MeV. The influnce of La2O3 on the shielding parameters was examined. Among the studied glasses, La2.5 posseses the highest μm values. Also, La2.5 sample has the lowest transmission fraction, which implies that more photons can be attenuated with La2.5 glass using a thin glass layer. From the transmission fraction results, we found that thick glasses are needed to attenuate gamma rays coming at high energies. At 0.511 MeV, the half value layer (HVL) value of the La0.0 glass is 1.49 cm while, at the same energy, the HVL value of the La2.5 glass is 1.44 cm.
AtıfScopus34OpenAlex35İncele - MakaleYalnız künye2020Scopus SJRQ2Investigation of the radiation shielding capability of xPbO – (50 - x) BaO – 50 B 2O 3 glass system using Geant4, Fluka, WinXCOM and comparison of data with the experimental data
Aşkin, A.; Mutuwong, C.; Nutaro, T.; Dal, M.
In this study, mass attenuation coefficient (μm), transmission fractions (T), effective atomic numbers (Z eff) and half-value layer (HVL) of the xPbO –(50 - x) BaO –50 B 2O 3 (where x=10,20,30,40mol%) glass system have been determined from the Monte Carlo simulations carried out with Geant4 and Fluka simulation toolkits and WinXCOM database software. The calculated results were compared with the experimentally obtained μm values of the selected glass in order to validate the Geant4 model of HPGe detector and Fluka model of NaI(Tl) detectors. T, Z eff and HVL shielding parameters of the studied glass system indicate that increase of PbO content from 10 to 40% results in a better shielding behaviour thanks to the high atomic number of lead.
AtıfScopus12WoS8OpenAlex12İncele - MakaleAçık Erişim2020Scopus SJRQ1Enhanced corrosion properties of biological NiTi alloy by hydroxyapatite and bioglass based biocomposite coatings
Say, Y.; Aksakal, B.
Enhanced corrosion resistance is always an obligatory property in biomedical applications. For this purpose, the surfaces of NiTi alloy were duplex coated both by Hydroxyapatite (HA)/Silver (Ag) and BioGlass (BG)/Silver (Ag) using the sol-gel method. The surface morphologies, and corrosion behaviours of the coatings were examined via SEM, EDS, XRD, and mechanically, by means of hardness as well as adhesion and corrosion tests. SEM analyses showed that the homogenous and crack-free structures were obtained in the biocomposite coatings. Spherical-like structures in the coatings were observed and pitting type of corrosion was formed in the biocomposite coated NiTi surfaces. After the corrosion tests, enhanced corrosion resistance was observed in both HA- and BG- based coatings. However, HA-based HA/Ag coatings on NiTi alloys were obtained to have higher adhesion strength as well as higher corrosion resistance compared to the BG-based biocomposite coatings. The findings in the present study can help the design of future implants with higher corrosion resistance.
AtıfScopus38WoS37OpenAlex42İncele - MakaleAçık Erişim2020Scopus SJRQ4Parameter estimation of some archimedean copulas based on minimum cramer-von-mises distance
Susam, Selim Orhun
The purpose of this paper is to introduce a new estimation method for estimating the Archimedean copula dependence parameter in the non-parametric setting. The estimation of the dependence parameter has been selected as the value that minimizes the Cramer-von-Mises distance which measures the distance between Empirical Bernstein Kendall distribution function and true Kendall distribution function. AMonte Carlo study is performedto measure the performance of thenewestimator and compared to conventional estimation methods. In terms of estimation performance, simulation results show that the proposed Minumum Cramer-von-Mises estimation method has a good performance for low dependence and a small sample size when compared with the other estimation methods. The new minimum distance estimation of the dependence parameter is applied to model the dependence of two real data sets.
AtıfScopus13WoS9OpenAlex10İncele - MakaleAçık Erişim2020Scopus SJRQ3Antioxidant effects of oleuropein on hydrogen peroxide-induced neuronal stress-an in vitro study
Kucukgul, Altug; Isgor, Mehmet M.; Duzguner, Vesile; Atabay, Meryem N.; Kucukgul, Azime
Background: Persistent oxidative stress can lead to chronic inflammation and mediate most chronic diseases including neurological disorders. Oleuropein has been shown to be a potent antioxidant molecule in olive oil leaf having antioxidative properties. Objective: The aim of this study was to investigate the protective effects of oleuropein against oxidative stress in human glioblastoma cells. Methods: Human glioblastoma cells (U87) were pretreated with oleuropein (OP) essential oil 10 µM. After 30 minutes, 100 µM H2 O2 was added to the cells for three hours. Cell survival was quantified by colorimetric MTT assay. Glutathione level, total oxidant capacity, total antioxidant capacity and nitric oxide levels were determined by using specific spectrophotometric methods. The relative gene expression level of iNOS was performed by qRT-PCR method. Results: According to viability results, the effective concentration of H2 O2 (100µM) significantly decreased cell viability and oleuropein pretreatment significantly prevented the cell losses. Oleuropein regenerated total antioxidant capacity and glutathione levels decreased by H2 O2 exposure. In addition, nitric oxide and total oxidant capacity levels were also decreased after administration of oleuropein in treated cells. Conclusion: Oleuropein was found to have potent antioxidative properties in human glioblastoma cells. However, further studies and validations are needed in order to understand the exact neuroprotective mechanism of oleuropein.
AtıfScopus23OpenAlex24İncele - MakaleAçık Erişim2020Scopus SJRQ1Time-aware link prediction based on strengthened projection in bipartite networks
Aslan, Serpil; Kaya, B.
The traditional projection models in the bipartite networks involve many node pairs that consist of weak relationships. These node pairs lead to poor quality predictions as well as high computation time. In this paper, to cope with these problems, we firstly propose a novel projection model, which is called “Strengthened Projection Model”. Then, to predict the potential links in the future, we present a new link prediction approach based on the proposed projection model. Thanks to the proposed model, the computation time is shortened, and the high probability predictions are extracted. The majority of the previous works conducted in this area have used the classical proximity measure algorithms that only take into account the current network structure, regardless of when events occur in the network evolution. To overcome these limited methods, in this paper, we also propose a novel proximity measure algorithm that considers the bipartite network evolution. To the best of our knowledge, this is the first attempt that takes into account the time-awareness in bipartite networks. To evaluate the performance of our proposed approach, we conducted experiments on the academic information network. To construct this bipartite network, we collected data from IEEE Xplore. The experimental results show that the success of the proposed method is promising.
AtıfScopus11WoS9OpenAlex10İncele - MakaleAçık Erişim2020Scopus SJRQ1The Breast Size Satisfaction Survey (BSSS): Breast size dissatisfaction and its antecedents and outcomes in women from 40 nations
Swami, Viren; Tran, Ulrich S.; Barron, David; Afhami, Reza; Aimé, Annie; Almenara, Carlos A.; Alp Dal, Nursel; Amaral, Ana Carolina Soares; Andrianto, Sonny; Anjum, Gulnaz
The Breast Size Satisfaction Survey (BSSS) was established to assess women's breast size dissatisfaction and breasted experiences from a cross-national perspective. A total of 18,541 women were recruited from 61 research sites across 40 nations and completed measures of current-ideal breast size discrepancy, as well as measures of theorised antecedents (personality, Western and local media exposure, and proxies of socioeconomic status) and outcomes (weight and appearance dissatisfaction, breast awareness, and psychological well-being). In the total dataset, 47.5 % of women wanted larger breasts than they currently had, 23.2 % wanted smaller breasts, and 29.3 % were satisfied with their current breast size. There were significant cross-national differences in mean ideal breast size and absolute breast size dissatisfaction, but effect sizes were small (η2 = .02–.03). The results of multilevel modelling showed that greater Neuroticism, lower Conscientiousness, lower Western media exposure, greater local media exposure, lower financial security, and younger age were associated with greater breast size dissatisfaction across nations. In addition, greater absolute breast size dissatisfaction was associated with greater weight and appearance dissatisfaction, poorer breast awareness, and poorer psychological well-being across nations. These results indicate that breast size dissatisfaction is a global public health concern linked to women's psychological and physical well-being.
AtıfScopus68OpenAlex77İncele - MakaleYalnız künye2020Scopus SJRQ1Emergency department network under disaster conditions: The case of possible major Istanbul earthquake
Gul, Muhammet; Fuat Guneri, Ali; Gunal, Murat M.
Emergency departments (EDs) provide health care services to people in need of urgent care. Their role is remarkable when extraordinary events that affect the public, such as earthquakes, occur. In this paper, we present a hybrid framework to evaluate earthquake preparedness of EDs in cities. Our hybrid framework uses artificial neural networks (ANNs) to estimate number of casualties and discrete event simulation (DES) to analyse the effect of surge in patient demand in EDs, after an earthquake happens. At the core of our framework, Earthquake Time Emergency Department Network Simulation Model (ET-EDNETSIM) resides which can simulate patient movements in a network of multiple and coordinated EDs. With the design of simulation experiments, different resource levels and sharing rules between EDs can be evaluated. We demonstrated our framework in a network of five EDs located in a region of which is estimated to have the highest injury rate after an earthquake in Istanbul, Turkey. Results of our study contributed to the planning for expected earthquake in Istanbul. Simulating a network of EDs extends the individual ED studies in the literature and furthermore, our hybrid framework can help increase earthquake preparedness in cities around the world. On the methodological side, the use of ANN, which is a member of machine learning (ML) algorithms family, in our hybrid framework also shows the close links between ML and DES.
AtıfScopus30WoS31OpenAlex40İncele - MakaleAçık Erişim2020Scopus SJRQ2Fabrication of a novel acrylate polymer bearing chalcone and amide groups and investigation of its thermal and isoconversional kinetic analysis
Biryan, Fatih; Pihtili, Güzin
The aim of the article was to examine the thermal degradation, thermal decomposition kinetics and dielectric behavior of novel poly(APHP-Am–Ac). For this purpose, the novel monomer, 4-(3-(4-acetamidophenyl)-3-oxoprop-1-en-1-yl)phenyl acrylate (APHP-Am–Ac), was synthesized from 1-(4-aminophenyl)-3-(4-hydroxyphenyl) prop-2-en-1-one (APHP) and acetic anhydride reaction. The homopolymer P(APHP-Am–Ac) was prepared by free radical polymerization within dimethylformamide at 80 °C. The presence of rigid and bulky chalcone units in polymer side chains significantly improved the solubility of polyamides, giving them an amorphous nature and good thermal stability. The structural characterization of homopolymer was accomplished using FT-IR and NMR techniques. The thermal stability and degradation features of homopolymer have been performed by using TG analysis and FT-IR during partial degradation at different temperatures. The glass transition temperature of homopolymer was determined by DSC analysis. For thermal decomposition kinetics of poly(APHP-Am–Ac), Flynn–Wall–Ozawa and Kissinger methods were applied to thermogravimetric curves and apparent activation energies (Ea) calculated from these two methods. According to FWO, the activation energy (Ea) of the first step and the second step was found as: 157.78 kJ mol−1 and 151.81 kJ mol−1, respectively. For Kissinger’s model, Ea was calculated as 154.3 kJ mol−1 and 142.83 kJ mol−1, respectively. The dielectric and conductivity measurements of homopolymer were investigated by impedance analyzer technique in a range of 10 Hz–20 kHz frequency at different temperatures (from 25 to 120 °C). The results have been plotted as a function of frequency and temperatures. The values increased significantly with temperature.
AtıfScopus18WoS17OpenAlex18İncele - MakaleAçık Erişim2020Scopus SJRQ2Generalized quasi-einstein manifolds in contact geometry
Ünal, Inan
In this study, we investigate generalized quasi-Einstein normal metric contact pair manifolds. Initially, we deal with the elementary properties and existence of generalized quasi-Einstein normal metric contact pair manifolds. Later, we explore the generalized quasi-constant curvature of normal metric contact pair manifolds. It is proved that a normal metric contact pair manifold with generalized quasi-constant curvature is a generalized quasi-Einstein manifold. Normal metric contact pair manifolds satisfying cyclic parallel Ricci tensor and the Codazzi type of Ricci tensor are considered, and further prove that a generalized quasi-Einstein normal metric contact pair manifold does not satisfy Codazzi type of Ricci tensor. Finally, we characterize normal metric contact pair manifolds satisfying certain curvature conditions related toM-projective, conformal, and concircular curvature tensors. We show that a normal metric contact pair manifold with generalized quasi-constant curvature is locally isometric to the Hopf manifold S2n+1(1) x S1.
AtıfScopus5WoS3OpenAlex4İncele - MakaleYalnız künye2020Scopus SJRQ1Roles of aluminium shavings and calcite on engineering properties of cement-based composites
Gulmez, Nihan
In the construction industry, which large amounts of raw materials are consumed, substituting even small parts of concrete components with waste materials may lead to significant savings in consumed energy and natural resources hence support prevention of environmental pollution. In this study, an experimental program was carried out to find a reliable and eco-friendly method for eliminating large quantities of calcite powders originating from the marble processing industry and also aluminium shavings, a nondisposable product of metal working and shaping industry. Physical, mechanical and microstructural properties of the mortars produced with industrial wastes at different replacement percentages were evaluated. Adding up to 20% calcite to the mortar mixtures instead of cement did not cause a significant change in water absorption values compared to control mortar. In addition, the gradual increase of aluminium shavings in all mortar mixtures resulted in a significant decrease in apparent porosity. In mortars based on 10% calcite, an increase of 52% in 7-days flexural strength was achieved with the addition of 4% aluminium shavings.
AtıfScopus23WoS20OpenAlex24İncele - MakaleYalnız künye2020Scopus SJRQ2Phycoremediation of Precious Metals by Cladophora fracta From Mine Gallery Waters Causing Environmental Contamination
Topal, Murat; Öbek, Erdal; Arslan Topal, E. Işıl
We have presented a study to determine the possibility for the usage of Cladophora fracta as bioaccumulator of the metals (Au) and silver (Ag) both have characteristics of pollutant and precious in mine water. The highest concentrations accumulated by C. fracta were determined as 5.8 ± 0.3 and 5323 ± 75 µg/kg for Au and Ag, respectively. The results showed that the accumulation of the metals measured followed the order of Ag > Au. The Metal Pollution Index (MPI) values calculated between 39.37 × 10−3 and 175.7 × 10−3 were used to determine the pollution degree of C. fracta. As a result, it was determined that C. fracta highly accumulated the precious metals from the gallery water. Therefore, C. fracta was a good bioaccumulator for the remediation of Au and Ag in mine gallery waters. In this way, it is possible to minimize or eliminate the environmental risks of the precious metals in the gallery waters.
AtıfScopus9WoS6OpenAlex6İncele - MakaleYalnız künye2020Scopus SJRQ1A scale to measure sustainable campus services in higher education: “Sustainable Service Quality”
Ozdemir, Yasal; Kaya, Sema Kayapinar; Turhan, Erkan
This study aims to develop a measuring tool which can address two independent research areas in the literature: Sustainability in higher education and service quality in higher education. Both subjects are studied independently in the literature, showing a need for an integrated approach that bridges these areas. For achieving this purpose, a new scale was developed based on a questionnaire applied to two universities in Turkey. The scale aimed to measure the perceptions of the students regarding the quality of sustainable campus services. The questionnaire consisted of 22 questions on several aspects of campus services which are related to sustainability. A total of 234 samples were used for Exploratory Factor Analysis for determining the underlying structures in the data set. The scale was validated with satisfactory Kaiser-Meyer Olkin and Bartlett's test results. Five dimensions were extracted, which represent sustainable service quality. After validation, the scale was applied to two universities located in geographically and socio-economically different regions of Turkey. The term chosen for the proposed combined scale is Sustainable Service Quality (SusServQual). With additional data, t-tests were applied to 308 students aiming to compare the two universities based on perceived quality scores. The results show that the university located in the socio-economically more developed region performed better regarding the overall satisfaction score and four of the five dimensions. The scores were also weighted utilizing a modified method of Analytical Hierarchy Process. Instead of crisp numbers which forces the decision maker to think in mathematical terms while comparing criteria, linguistic terms, each of which corresponds to a fuzzy number were used. Thus, a more accurate evaluation was obtained where the decision maker's subjectivity and ambiguity of the situation are important.
AtıfScopus62WoS50OpenAlex77İncele