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Koleksiyondaki öğeler
- MakaleYayıncıda açık erişim2018Scopus SJRQ2Determination of pollution and heavy metal fractions in golden horn sediment sludge (Istanbul, Turkey)
Kanat, Gurdal; Ikizoglu, Bahar; Erguven, Gokhan Onder; Akgun, Berivan
In our study we studied pollution and heavy metal fractions in the Golden Horn (Istanbul, Turkey). This area has been exposed to domestic and industrial pollution for many years. Concentrations of Zn, Cr, Cu, Pb, Cd, and Ni heavy metals were determined in the study that was conducted to monitor the current state of pollution and changing conditions in the polluted estuary. Mean heavy metal concentrations were found as: Zn 70-260, Cr 26-110, Cu 70-135, Pb 8-50, Cd 0.1-2, and Ni 10-38 mg/kg. Results of the analysis showed that metal concentrations were usually low, indicating that the sediment was not too polluted in the present case. The range of ratios, different fractions of metal concentrations, and total metal concentrations in the samples were critical for potential toxicity and mobility of metals. Results of the analysis showed that heavy metal fractions in the sediment were usually found in residual forms. The values obtained in the study were also compared with the literature. It was found that surface sediments in the Golden Horn were less polluted than other areas. Establishment of sewer collectors and wastewater treatment plants has improved the heavy metal levels in the sediment.
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İncele - MakaleAçık Erişim2020Evaluation of the effect of COVID-19 on countries' sustainable development level: A comparative MCDM framework
Kaya, Sema Kayapinar
The extent of the outbreak of coronavirus disease (COVID-19) had a major impact on health, social life, economic and environmental activities in almost every country over the world. It has disrupted the sustainable development of countries and brought many uncertainties for their future capabilities. In this study, the effects of the COVID-19 on OECD countries' sustainable development were investigated, and the sustainable development performance of the countries was evaluated by the MultiAttributive Ideal-Real Comparative Analysis (MAIRCA) method. Data for the second quarter of 2020 and the same quarter of the previous year is considered. Then, the results obtained by the MAIRCA method were compared with two different multi-criteria decision-making (MCDM) methods called MABAC (Multi‐Attributive Border Approximation Area Comparison) and WASPAS (Weighted Aggregated Sum Product Assessment). The effectiveness and validity of the results obtained from these methods were tested with Spearman's correlation coefficient. Finally, to examine the effect of COVID-19 on the indicators of sustainable development, a non-parametric Wilcoxon signed-rank test was applied. As a result, it was concluded that COVID-19 negatively affected the sustainable development of countries. However, sustainable development performances of developed countries have been observed to be better than developing countries.
AtıfScopus49OpenAlex56İncele - MakaleAçık Erişim2018Scopus SJRQ3Effect of Tunceli garlic on some immunological parameters in Cyprinus carpio exposed to chlorpyrifos
Pala, Ayşegül; Şeker, Engin; Yonar, M. Enis
In this study, the effect of Tunceli garlic (Allium tuncelianium) on hemoglobin (Hb) level, oxidative radical production of neutrophils (Nitoblue tetrazolium assay-NBT activity) and total immunoglobulin (TI) content in carp (Cyprinus carpio) exposed to chlorpyrifos (CPF) was investigated. The 96 hour LC50 value of CPF on C. carpio was calculated to as 0.230 mg/L. The fishes were exposed to sublethal concentration of chlorpyrifos (1/8 of LC50 value: 0.029 mg/L), and Tunceli garlic (20 and 40 g/kg diet) was simultaneously administered for 21 days. Blood samples were taken from the fishes at 7, 14 and 21 days and analysed to determine the Hb levels, the NBT activity and the TI content. There was a significant decrease in the Hb level, the NBT activity and the TI content of CPF-treated fish. However, Tunceli garlic reversed the Hb level, the NBT activity and the TI content. In conclusion, this study demonstrated that CPF had a negative effect on the immunological values of the fish. The simultaneous administration of Tunceli garlic was neutralised CPF-induced toxicity.
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İncele - MakaleYalnız künye2020Scopus SJRQ4Preservative effect of coriander essential oil applied in different proportions on the storage of rainbow trout (Oncorhynchus mykiss) fillets
Kuzgun, Nermin Karaton; Erecevit Sönmez, Pınar; Tanyildizi, Muhammet Şaban
Aim of this study, the sensorial, microbiological, and chemical features during shelf life at 2 ± 2 °C of rainbow trout fillets samples treatment with coriander essential oils were examined of protective effect of oils. According to the findings of the research, the storage during of fillets ended on day 9th, that of control on day 12th, that of samples applied with coriander oils 0.1% on day 15th, which of fillets applied with coriander oils 0.25% and applied with coriander oils 0.5% on day 18th. The minimum number of bacteria, values of TVB-N and TBA were founded in trout fillets treatment with 0.5% coriander essential oil. In terms of the sensory quality of the fillets, as assessed by panelists participating in the panel, it was detected that highest point was given to the fillets groups to which coriander essential oil of 0.5% had been enforced, and as a result, with this application, it was underlined that was obtained in a positive direction of a flavor very different other than ordinary fish flavor by panelists.
AtıfScopus5WoS2İncele - MakaleYalnız künye2018Scopus SJRQ1A comparative outline for quantifying risk ratings in occupational health and safety risk assessment
Gul, Muhammet; Ak, M. Fatih
The concept of risk assessment has been introduced as an examination of safety in the workplace to enable assessments as to whether sufficient precautions have been taken or if more should be done to prevent potential harm. Hazardous industries have faced serious fatalities related to work, workplaces, and workers as a consequence of their high-risk processes. Therefore, in this work, a novel and comparative methodology for quantifying risk ratings in occupational health and safety risk assessment is proposed. A 5 × 5 risk matrix is initially determined, and the fuzzy technique for order preference by similarity to ideal solution (FTOPSIS) method is then applied to rank identified hazards. As a novelty to the knowledge, two parameters of the 5 × 5 matrix method, likelihood and severity, are subjectively assessed by occupational health and safety experts, and then importance levels for these parameters are determined using the Pythagorean fuzzy analytic hierarchy process (PFAHP). In the proposed approach, analysts use linguistic terms and Pythagorean fuzzy sets, which provide greater independence in their evaluations. An outline that enables comparison of the results of this study with the circumcenter of centroids method and the fuzzy AHP-fuzzy VIKOR integrated method in quantifying risk ratings is also provided. In order to present the practicality of this work, a case study in an underground copper and zinc mine is carried out.
AtıfScopus194WoS153OpenAlex211İncele - MakaleAçık Erişim2019Scopus SJRQ1A study on the technological pedagogical contextual knowledge of science teacher candidates across different years of study
Karakaya Cirit, Didem; Canpolat, Erdal
This case study survey investigates the Technological Pedagogical Contextual Knowledge (TPCK) of Science Teacher Candidates (STC) across different years of study in the Topic of Renewable Energy (TRE). In line with the transformative model, the study treats TRE-TPCK as a new knowledge domain emerging from the interaction between content, technology, pedagogy and contextual knowledge. Participants were 36 Science Education students who were in their 1st, 2nd, 3rd and 4th years of study during the 2014–2015 academic year. Teacher candidates’ TPCK was identified through semi-structured interviews based on (1) Vignettes, (2) Anecdotes from a teacher named Zeynep and the (3) Content Presentation Technique (CPT). The data were analyzed by using the content analysis technique. The findings showed that the TRE-TPCK of teacher candidates across different years of study was at a similar and less-than-ideal level. STCs in different years of study mostly disregarded the macro and meso contexts when teaching the topic of renewable energy and were partially competent in the sub-meso, micro and sub-micro contexts. They particularly lacked technology-integrated evaluation knowledge when teaching TRE.
AtıfScopus8WoS8OpenAlex10İncele - MakaleAçık Erişim2020Scopus SJRQ2Performance of Cladophora fracta for Bioaccumulation of Critical Raw Materials from Mine Gallery Waters
Topal, Murat; Öbek, Erdal; Arslan Topal, E. Işıl
We investigated the accumulation of critical raw materials (CRMs) in macroalga (green alga Cladophora fracta) in mine gallery water with the aim of presentation of the possibility of using the algae as a bioaccumulator of CRMs. The CRMs investigated in the present study were lanthanum (La), vanadium (V), tungsten (W), scandium (Sc), bismuth (Bi), antimony (Sb), gallium (Ga) and cobalt (Co). The highest concentrations of La, V, W, Sc, Bi, Sb, Ga and Co were determined as 3.16 ± 0.15, 22 ± 1.0, 2.0 ± 0.1, 2.4 ± 0.12, 0.21 ± 0.01, 2.47 ± 0.13, 1.4 ± 0.07 and 7.28 ± 0.35 mg/kg, respectively. Bioconcentration factor values followed the order of La > V>W > Ga > Sb > Bi > Co > Sc. Also, metal pollution index (MPI) is used in order to identify the degree of pollution of C. fracta. The MPI values calculated were between 1.09 and 2.2. As a result, it was determined that C. fracta highly accumulated the CRMs from the mine gallery water and was a good bioaccumulator in remediation technology. In this way, it is possible to minimize or eliminate the environmental risks of the materials in the gallery waters.
AtıfScopus5WoS5OpenAlex6İncele - MakaleYalnız künye2020Scopus SJRQ2Hospital service quality evaluation: an integrated model based on Pythagorean fuzzy AHP and fuzzy TOPSIS
Yucesan, Melih; Gul, Muhammet
Providing better hospital service quality is one of the major concerns of healthcare industry in the world. Since health services in Turkey are provided in a very competitive environment, for making a better choice, the services delivered by the public and private hospitals should be evaluated according to the viewpoint of stakeholders in terms of satisfaction. In this study, a model proposal is presented based on the concept of Pythagorean fuzzy analytic hierarchy process and Pythagorean fuzzy technique for order preference by similarity to ideal solution method to provide an accurate decision-making process for evaluating the hospital service quality. We study under fuzzy environment to reduce uncertainty and vagueness, and use linguistic variables parameterized by Pythagorean fuzzy numbers. The proposed approach is separated from others with the integration of the methods in a way providing a systematic fuzzy decision-making process. A case study including 32 service quality criteria and two public and one private hospitals in Turkey assessed by 32 evaluators by medical staff, hospital executives, auxiliaries, and patients is performed to demonstrate the applicability and validity of the proposed approach. On conclusion, integrated model produces reliable and suggestive outcomes better representing the vagueness of decision-making process.
AtıfScopus164WoS132OpenAlex190İncele - MakaleAçık Erişim2019Scopus SJRQ2Effect of MgO,Al2O3 and FeCr2O4 on microstructure and wear resistance of Babbitt metal (Sn-Sb-Cu)
Tasgin, Yahya
In this study, the Sn-Sb-Cu alloy known as Babbitt metal and used as the coating material for the screw die surface of the journal bearings of the hydroelectric plants was reinforced with magnesium oxide (MgO), aluminium oxide (Al2O3) and ferrochromium (FeCr2O4) in order to ensure more efficient use of this alloy, formation were examined. The Babbitt prevent contact of the surface of the coating alloy with each other by acting as a separating oil layer having a 150 bar pressure. It is desired that the coating surface both resists against the high pressure applied and some part of the coating surface is asked to prevent from separating the surface of screw die as a result of high speed rotational motion and thus, damaging the shaft. Then, it was aimed to determine the wear resistance of the material as coating and the effects of the added%10 MgO,%10 Al2O3 and%10 FeCr2O4 on wear of material. As a result of the assessments carried out, it was suggested that the wear resistance of the coating would increase when the compound of Al2O3 was added into Babbitt metal. Purpose of the article used as coating material of babbitt metal, being investigated how to exert strong posture affected, under high pressure.
AtıfScopus8WoS7OpenAlex7İncele - MakaleAçık Erişim2019Scopus SJRQ3The effects of deposition potential on the optical, morphological and mechanical properties of DLC films produced by electrochemical deposition technique at low voltages
Aslan, Naim; Başman, Necati; Uzun, Orhan; Erkovan, Mustafa; Yakuphanoǧlu, Fahrettin
Diamond-like carbon (DLC) films were electrochemically deposited onto indium tin oxide (ITO) substrates using acetic acid and deionized water as electrolyte at low deposition voltages (2.4 V and 60 V). The transmittance of the films was investigated by UV spectrometry. Transmittance measurements versus wavelength revealed that the films transmit 86 % to 89 % light in visible region and band gap of the films varies between 3.87 eV and 3.89 eV. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used for structural characterization to evaluate surface morphology of the DLC films. The grain size and the surface roughness increased for the films prepared at higher deposition potential, while their measured average height decreased. The mechanical properties (hardness H and elastic modulus Er) were determined from load-displacement curves which were obtained by using nanoindentation method. Hardness and elastic modulus of the films increased as the deposition voltage of the films increased from 2.4 V to 60 V.
AtıfScopus9OpenAlex4İncele - MakaleAçık Erişim2020Scopus SJRQ2A novel method for performance improvement of chaos-based substitution boxes
Artuğer, Firat; Özkaynak, Fatih
Symmetry plays an important role in nonlinear system theory. In particular, it offers several methods by which to understand and model the chaotic behavior of mathematical, physical and biological systems. This study examines chaotic behavior in the field of information security. A novel method is proposed to improve the performance of chaos-based substitution box structures. Substitution box structures have a special role in block cipher algorithms, since they are the only nonlinear components in substitution permutation network architectures. However, the substitution box structures used in modern block encryption algorithms contain various vulnerabilities to side-channel attacks. Recent studies have shown that chaos-based designs can offer a variety of opportunities to prevent side-channel attacks. However, the problem of chaos-based designs is that substitution box performance criteria are worse than designs based on mathematical transformation. In this study, a postprocessing algorithm is proposed to improve the performance of chaos-based designs. The analysis results show that the proposed method can improve the performance criteria. The importance of these results is that chaos-based designs may offer opportunities for other practical applications in addition to the prevention of side-channel attacks.
AtıfScopus55WoS44OpenAlex56İncele - MakaleYalnız künye2019Scopus SJRQ2Investigation of the anti-apoptotic activity of ozone therapy in rainbow trout macrophages infected with Yersinia ruckeri
Küçükgül, Azime; Küçükgül, Altuğ; Gönenci, Ramazan; Özsoy, Şule Yurdagül; Kutlu, Banu; Işgör, Mehmet Mustafa
Yersinia ruckeri is the causal agent of enteric redmouth (ERM) in trout. This study aimed to investigate the effectiveness of nontoxic ozone on Y. ruckeri-infected trout cells in in vitro conditions. Rainbow trout macrophages (RTS-11) were exposed to Y. ruckeri for 24 h after being incubated with the ozonized medium at nontoxic concentration. Effective concentrations of nontoxic ozone (3 gamma) and bacteria (1.5 x 108 cfu/mL) were determined by viability tests. The expression of caspases 1, 3, 8, and 12 was determined by real-time PCR and protein levels investigated by ELISA method. Apoptotic-necrotic cell ratios were determined by acridine orange and ethidium bromide staining. Bacterial stimulations of caspases (1, 3, 8, and 12) were suppressed by ozone mostly at the translational level. While bacterial infection increased the count of apoptotic and necrotic cells at different stages, ozone significantly reduced this condition. Obtained data indicate possible use of nontoxic ozone as a safe and effective treatment alternative for increasing host defenses and eliminating the infection in the case of yersiniosis in fish.
AtıfWoS1OpenAlex3İncele - MakaleAçık Erişim2018Scopus SJRQ2Weaning practices of mothers in eastern Turkey; [Práticas maternas de desmame no leste da Turquia]
Gürarslan Baş, Nazan; Karatay, Gülnaz; Arikan, Duygu
Objective: The study aimed to determine the practices used by breastfeeding mothers to wean their children from the breast. Method: This qualitative–quantitative research was conducted with mothers whose children were registered the pediatric clinics of a state hospital between June and September 2016. In accordance with a purposeful sampling method, 232 mothers of children between the ages of 2 and 5 years were included in the study. Data were collected through face-to-face interviews using a questionnaire with demographic characteristics of mothers as well as their weaning practices. The data obtained were analyzed with a computer-assisted program using number and percentage distributions. Results: The mean breastfeeding duration was 19.00 ± 7.11 months. It was determined that the majority of mothers (56.5%) used traditional methods for weaning their children. These included applying substances with a bad taste (58.1%) to their breasts, covering their breasts with various materials (26.2%) to make the child not want to nurse anymore, and using a pacifier or feeding bottle (9.2%) to substitute for the mother's breast. Conclusions: It was observed that more than half of the mothers were used some traditional practices that could cause trauma in their children, instead of natural weaning.
AtıfScopus18WoS19OpenAlex26İncele - MakaleYalnız künye2018Scopus SJRQ4A Current Overview of Education Problems in Turkey
Şener, Gönül
The fact that educational outcomes have not been at the desired level in recent years reveals the importance of determining the problems experienced in the education system. Accordingly, it has been considered worthwhile to investigate the determination of the general opinions of teachers, who are the most important components of classroom management, about the current problems they are experiencing. Qualitative research method was used in the study. The question of “List the current problems you are experiencing in the national education system” was asked to 96 teachers to receive their opinions. According to the results obtained from the research, it was seen that the problems experienced were mostly student-sourced and this problem was followed by finance, program, teacher and political-sourced problems.
AtıfScopus7İncele - BildiriAçık Erişim2017Face recognition based on convolutional neural network
Coskun, Musab; Ucar, Aysegul; Yildirim, Ozal; Demir, Yakup
Face recognition is of great importance to real world applications such as video surveillance, human machine interaction and security systems. As compared to traditional machine learning approaches, deep learning based methods have shown better performances in terms of accuracy and speed of processing in image recognition. This paper proposes a modified Convolutional Neural Network (CNN) architecture by adding two normalization operations to two of the layers. The normalization operation which is batch normalization provided acceleration of the network. CNN architecture was employed to extract distinctive face features and Softmax classifier was used to classify faces in the fully connected layer of CNN. In the experiment part, Georgia Tech Database showed that the proposed approach has improved the face recognition performance with better recognition results.
AtıfScopus250OpenAlex295İncele - MakaleYalnız künye2017Scopus SJRQ2Characterisation of natural streams using community indices and basal resources of macroinvertebrates in the upper Euphrates Basin
Gültekin, Zuhal; Remmers, Wolfram; Aydin, Rahmi; Winkelmann, Carola; Hellmann, Claudia
The characterisation of natural stream conditions is the first important step to analyse ecological quality of streams in the Euphrates basin. We found that the community indices correspond to very good ecological conditions in five natural streams of that region. The macroinvertebrates composition differed significantly between September and May. Number of taxa and Shannon index were significantly higher in autumn than in spring. FPOM and biofilm were the most relevant basal resources of benthic invertebrates.
AtıfScopus1OpenAlex2İncele - MakaleYalnız künye2017Scopus SJRQ1A beam search approach for solving type II robotic parallel assembly line balancing problem
Çil, Zeynel Abidin; Mete, Süleyman; Özceylan, Eren; Ağpak, Kürşad
In a robotic assembly line, a series of stations are arranged along a conveyor belt and a robot performs on tasks at each station. Parallel assembly lines can provide improving line balance, productivity and so on. Combining robotic and parallel assembly lines ensure increasing flexibility of system, capacity and decreasing breakdown sensitivity. Although aforementioned benefits, balancing of robotic parallel assembly lines is lacking – to the best knowledge of the authors- in the literature. Therefore, a mathematical model is proposed to define/solve the problem and also iterative beam search (IBS), best search method based on IBS (BIBS) and cutting BIBS (CBIBS) algorithms are presented to solve the large-size problem due to the complexity of the problem. The algorithm also tested on the generated benchmark problems for robotic parallel assembly line balancing problem. The superior performances of the proposed algorithms are verified by using a statistical test. The results show that the algorithms are very competitive and promising tool for further researches in the literature.
AtıfScopus56WoS48OpenAlex56İncele - MakaleAçık Erişim2017Scopus SJRQ2Optimization of an Analytical Method for Determination of Pyrene in Smoked Meat Products
Ince, Muharrem; Kaplan Ince, Olcay; Yaman, Mehmet
In the present study, an analytical method was optimized for determination of pyrene by solid-phase extraction in Turkish foodstuffs including chicken and grilled meat samples. In accordance with this purpose, all of the parameters that may affect the signal of pyrene during analysis processes were optimized using high-performance liquid chromatography–mass spectrometry system. The optimized parameters for column temperature, injection volume, mobile-phase flow rate, and fragmentor potential were found to be 45 °C, 60 μL, 0.6 mL min−1, and 130 V, respectively. The optimized high-performance liquid chromatography–mass spectrometry method was applied for the determination and evaluation of pyrene in food samples that include chicken and grilled meat. The pyrene amount in meat samples was obtained in the range from 2.3 to 4.4 μg kg−1 for the normal grilled meat and chicken samples and from 12 to 135 μg kg−1 for exceedingly grilled samples. The results show that the concentration of pyrene is significantly dependent on the type of meat sample and cooking source. The limit of detection and quantitation was found to be 0.5 μg L−1 and 1.53 μg L−1, respectively.
AtıfScopus5WoS5OpenAlex7İncele - MakaleYalnız künye2017Scopus SJRQ4Growth and bioaccumulation of cadmium, zinc, lead, copper in Dunaliella sp. isolated from Homa lagoon, eastern Aegean Sea
Kutlu, Banu; Mutlu, Ekrem
Present study consists the growth of cell and bioaccumulation capacity of Cadmium (Cd), Zinc (Zn), Lead (Pb), Copper (Cu) by Dunaliella sp. isolated from Homa Lagoon, Eastern Aegean, Turkey. Sterile medium f/2 was used for the cultivation. Growth rate, mean growth rate, relative growth rate and generation time of Dunaliella sp. were calculated for determining the growth of cell. In addition, optimum pH values were determined for each heavy metal. Our results pointed out that the optimum time for harvesting Dunaliella sp. was in 8 days. Uptake of heavy metals of Dunaliella sp. showed high tendency for zinc accumulation followed by copper, lead, and the lowest tendency was for cadmium. Highest bioaccumulation of Zn was determined to be 151.64 µg/L at 2.45 of pH under in situ conditions. pH had noticeably affected the bioaccumulation capacity of Dunaliella sp.
AtıfScopus4İncele - MakaleYalnız künye2018Scopus SJRQ2Mechanical and flow properties of blends of polypropylene and powder coating recyclates with and without addition of maleic anhydride
Kismet, Yilmaz; Wagner, Manfred H.
In this research, from 10% to 40% by weight of hydrolyzed powder coating recyclates were used as filler in polypropylene (PP). Firstly, PP and filler were dry-mixed and then, in order to get a homogeneous mixture, were extruded at 180°C. The resulting compounds were cooled and granulated, and by use of an injection molding machine at 180–200°C, standard tensile test bars were produced. Tensile stress, three-point bending strength, and izod impact strength of these specimens containing different types of filler and different filler concentrations were tested. The results are presented, and the effects of type and content of hydrolyzed powder coating waste on the mechanical properties of polypropylene are discussed. Also, the change in melt flow index of polypropylene as a function of filler content is analyzed. Furthermore, the bonding mechanism of filler and matrix material was examined by electron microscopy.
AtıfScopus12WoS10OpenAlex13İncele
