Koleksiyon/r/munzur/2

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Koleksiyondaki öğeler

  • MakaleAçık Erişim2019Scopus SJRQ2
    Electrical characterization of solar sensitive zinc oxide doped-amorphous carbon photodiode

    Koç, Mümin Mehmet; Aslan, Naim; Erkovan, Mustafa; Aksakal, Bünyamin; Uzun, Orhan; Farooq, W. Aslam; Yakuphanoğlu, Fahrettin

    A new solar-sensitive zinc oxide doped-amorphous carbon diode was fabricated using the electrochemical deposition technique. The current-voltage characteristics of the fabricated Al/ZnO-a:C/p-Si/Al diode were investigated under dark and various lighting intensities using both I-V and C-V methods. The fabricated diode was characterized by XRD, SEM-EDS, FTIR and XPS analysis. Through the analysis, it was determined that the photocurrents increased with increasing intensity of incident light. The capacitance-voltage (C-V) characteristics revealed that the capacitance of the diode depended on voltage, frequency and illumination, indicating the existence of a continuous distribution of interface states. It was found that the capacitance changed drastically with changing frequency and separation was observed in different frequencies, as identified in the reverse bias region. The ideality factor obtained was found to be higher than unity, with the average barrier height and ideality factor of the diode were found to be 0.528 ± 0.0069 eV and 5.24 ± 0.39, respectively. The newly fabricated ZnO-doped amorphous carbon (Al/ZnO-a:C/p-Si/Al) photodiode exhibited good solar sensitivity. The overall results indicated that the fabricated Al/ZnO-a:C/p-Si can be used as a solar sensitive diode in optoelectronic device applications as an alternative to graphene-based materials.

    • SDG 7 · Erişilebilir ve Temiz Enerji
    AtıfScopus41OpenAlex46
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  • MakaleYayıncıda açık erişim2019Scopus SJRQ2
    Evaluation of pharmacological activity of heterobimetallic coordination compounds containing n, n-bis (2-hydroxyethyl)-ethylenediamine on ht29, hela, c6 and vero cells

    Aydin, Ali; Korkmaz, Şengül Aslan

    The present study was conducted in order to investigate the pharmacological activities of three heterobimetallic coordination compounds: [Cd(N-bishydeten)2 ][Ni(CN)4 ] (C1), [Cu2 (N-bishydeten)2 Co(CN)6 ].3H2 O (C2), and K[Cd(N-bishydeten)Co(CN)6 ].1.5H2 O (C3) (N-bishydeten = N,N-bis(2-hydroxyethyl)-ethylenediamine). This paper describes the ability of complexes to inhibit cell growth, cell migration and human topoisomerase I and to interact with DNA/BSA; this paper also evaluates the potential mechanisms of action exhibited by these compounds via the use of powerful measurement techniques. Studies on HT29, HeLa, C6 and Vero cells revealed that each compound demonstrated significant antiproliferative activity in conjunction with regressed cell migration velocity and caused apoptotic changes in morphology. There are strong data suggesting that the mechanisms of action exhibited by these compounds are associated with their DNA/BSA binding features. The IC50 and binding constant range for the compounds are 20-180 µM and 1.2-3.2 x 104 M-1, respectively. Moreover, we observed that these compounds alter the P53-Bcl-2 ratio and inhibit the relaxation activity of human topoisomerase I. Furthermore, a correlation between the antiproliferative effects of these compounds and their cytotoxic activity was observed. In conclusion, preliminary information demonstrates that these compounds have been found to exhibit effective antiproliferative activity against cancer cell lines, indicating that they are a potent candidate for further pharmacological study.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    AtıfScopus5WoS5OpenAlex3
    ScopusWeb of SciencePubMedİncele
  • MakaleAçık Erişim2018Scopus SJRQ2
    Dark, bright optical and other solitons with conformable space-time fractional second-order spatiotemporal dispersion

    Bulut, Hasan; Sulaiman, Tukur Abdulkadir; Baskonus, Haci Mehmet

    This paper constructs dark, bright, combined dark-bright, singular, combined singular soliton optical and singular periodic solutions to the conformable space-time fractional second order nonlinear Schrödinger equation with group velocity dispersion coefficient and spatiotemporal dispersion by using the extended sinh-Gordon equation expansion method. The constraint conditions for the existence of valid soliton solutions are given. The reported results in this study may be helpful in explaining the physical meaning of the studied model.

    AtıfScopus51WoS49OpenAlex53
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  • MakaleAçık Erişim2019Scopus SJRQ2
    Automated detection of diabetic subject using pre-trained 2D-CNN models with frequency spectrum images extracted from heart rate signals

    Yildirim, Ozal; Talo, Muhammed; Ay, B.; Baloglu, Ulas Baran; Aydin, G.; Acharya, U. Rajendra

    In this study, a deep-transfer learning approach is proposed for the automated diagnosis of diabetes mellitus (DM), using heart rate (HR) signals obtained from electrocardiogram (ECG) data. Recent progress in deep learning has contributed significantly to improvement in the quality of healthcare. In order for deep learning models to perform well, large datasets are required for training. However, a difficulty in the biomedical field is the lack of clinical data with expert annotation. A recent, commonly implemented technique to train deep learning models using small datasets is to transfer the weighting, developed from a large dataset, to the current model. This deep learning transfer strategy is generally employed for two-dimensional signals. Herein, the weighting of models pre-trained using two-dimensional large image data was applied to one-dimensional HR signals. The one-dimensional HR signals were then converted into frequency spectrum images, which were utilized for application to well-known pre-trained models, specifically: AlexNet, VggNet, ResNet, and DenseNet. The DenseNet pre-trained model yielded the highest classification average accuracy of 97.62%, and sensitivity of 100%, to detect DM subjects via HR signal recordings. In the future, we intend to further test this developed model by utilizing additional data along with cloud-based storage to diagnose DM via heart signal analysis.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    AtıfScopus145OpenAlex152
    ScopusWeb of SciencePubMedİncele
  • Kitap BölümüYalnız künye2021
    Challenges, novel applications, and future prospects of chalcogenides and chalcogenide-based nanomaterials for photocatalysis

    Ates, Mehmet; Tanaydın, Mehmet Kayra; Yılmaz, Ersen

    Nanomaterials are composed of several atoms or molecules, which may be of various sizes and morphologies. Manmade nanomaterials are specially produced to take advantage of the unique properties of nanoscale. There are many metal chalcogenides with different structures and compositions such as CdSe, InAs, CdS, GaN, InGeAs, CdTe, PbS, PbSe, ZnS, Na2S, CaTe, Ti2S, and Cu2Se. The diversity of metal chalcogenides is related to the orbit of transition metals. In this chapter, new studies using chalcogenide compounds as photocatalysts were explained under the subtopics of metal chalcogenides and their properties, semiconductive nanostructures, nanomaterial production technique, chemical synthesis methods, and metal chalcogenides as photocatalysts. Novel applications of metal chalcogenide-based materials like water splitters, organic pollutant degraders, self-cleaning agents chalcogenide glasses and thermoelectric materials are explained in detail under the relevant headings. Future prospects of chalcogenides are also evaluated from a different perspective.

    AtıfScopus30OpenAlex26
    Scopusİncele
  • MakaleYalnız künye2018Scopus SJRQ4
    400 MHz NMR Study of Isotope Effects on Albumin in H2O/D2O Solutions

    Korunur, S.; Zengin, B.; Yılmaz, A.

    Abstract: Chemical shift measurements were performed for several percentages of H2O added to D2O, in several H2O/D2O mixtures without and with a single concentration of albumin, and also in a mixture of 0.1H2O/0.9D2O containing increasing concentrations of albumin. The chemical shifts of pure mixtures decreases with increasing fraction of pure water. This is closely related to isotope effects. The chemical shift corrected for isotope effects increases with percentage of H2O. The chemical shift obtained for the mixture of 0.1H2O/0.9D2O increases with increasing concentration of albumin. These increments are consistent with fast chemical exchange in H2O/D2O mixture. In conclusion, present study reveals the presence of isotope effect on albumin in H2O/D2O solutions, and demonstrates fast chemical exchange in D2O solutions with albumin in a different way.

    AtıfScopus1WoS1OpenAlex1
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  • MakaleAçık Erişim2019Scopus SJRQ2
    Using 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.

    • SDG 2 · Açlığa Son
    AtıfScopus4WoS4OpenAlex8
    ScopusWeb of SciencePubMedİncele
  • MakaleAçık Erişim2018Scopus SJRQ3
    Recognition of road type and quality for advanced driver assistance systems with deep learning

    Tumen, Vedat; Yildirim, Ozal; Ergen, Burhan

    To develop effective advanced driving assistance systems, it is important to accurately recognize current driving environments and make critical decisions about driving processes. Preventing accidents through the interaction between the driving assistance systems and the environment and ensuring optimum driving dynamics are the main topics in this field. Vehicles need to recognize the road type and quality at a high accuracy to ensure the most suitable driving for the road type. It is also important to use both uncomplicated and cost-effective systems when performing this detection. In this study, a deep learning-based approach that can be used in vehicle driver assistance systems is proposed to automatically recognize road type and quality. Using this approach, it is possible to determine the road type and the quality of the road using only driving images as the input data. A new convolutional neural network model is designed for classification of the driving images. Driving images obtained from Google Street View are used to evaluate the recognition system for an actual driving environment. The proposed approach shows that the road types were determined with accuracy of 91.41 %, and the pothole road–smooth road distinction was successful at 91.07 %. It can be said that the proposed method is an effective structure that can be used for advanced driving support systems, V2I communications systems, and similar intelligent transportation systems.

    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
    • SDG 11 · Sürdürülebilir Şehirler ve Topluluklar
    AtıfScopus22WoS16OpenAlex25
    ScopusWeb of Scienceİncele
  • MakaleAçık Erişim2018Scopus SJRQ1
    Reference-plane-invariant waveguide method for electromagnetic characterization of bi-axial bianisotropic metamaterials

    Hasar, Ugur Cem; Yildiz, Gul; Bute, Musa; Muratoglu, Abdurrahim

    In this paper, we investigate a reference-plane invariant (RPI) method for electromagnetic property extraction of bi-axial bianisotropic metamaterial (MM) slabs. In order to obtain unique properties, we applied the frequency varying technique in order to determine the location of the slab within its cell. For validation of the proposed method, we first simulated and then measured scattering parameters of a MM slab constructed by split-ring-resonators, next extracted its electromagnetic properties, and finally compared extracted properties by those retrieved by another method which requires reference-plane information. From the comparison, we noted that whereas our proposed method correctly retrieved electromagnetic properties without knowing the value of reference plane transformation factors, the accuracy of the tested method was seriously influenced by any inaccurate reference plane information.

    AtıfScopus7WoS5OpenAlex8
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  • Kitap BölümüYalnız künye2021
    Fine–kinney-based occupational risk assessment using interval type-2 fuzzy vikor

    Gul, Muhammet; Mete, Suleyman; Serin, Faruk; Celik, Erkan

    In this chapter, we improved Fine–Kinney occupational risk assessment approach with interval type-2 fuzzy VIKOR (IT2FVIKOR). VIKOR is a compromise multi-attribute decision-making method proposed by Opricovic (1998). Similar to other compromised solution-based approaches, it considers the solution which is closest to the ideal. In this chapter, we adapted the interval type-2 fuzzy sets (IT2FSs) into VIKOR as it reflects the uncertainty well in decision-making. IT2FVIKOR algorithm under the Fine–Kinney concept provides a useful and solid approach to the occupational health and safety risk assessment. In addition to proposing this new approach, a case study is performed in a gun and rifle barrel external surface oxidation and coloring unit of a gun factory. A validation and a sensitivity analysis is also attached to this study. Finally, the proposed approach is implemented in Python.

    AtıfScopus4OpenAlex5
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  • MakaleYalnız künye2019Scopus SJRQ3
    Effects of temperature and impactor nose diameter on the impact behavior of PA6 and PP thermoplastic composites

    Dogan, Akar; Arman, Yusuf

    In this study, the effects of temperature and impactor nose diameter on the impact behavior of woven glass-reinforced polyamide 6 (PA6) and polypropylene (PP) thermoplastic composites were investigated experimentally. Impact energies are chosen as 10, 30, 50, 70, 90, 110, 130, and 170 J. The thickness of composite materials is 4 mm. Impact tests were performed using a drop weight impact testing machine, CEAST-Fractovis Plus, and the load capacity of test machine is 22 kN. Hemispherical impactor nose diameter of 12, 7, and 20 mm were used as an impactor. The tests are conducted at room temperature (20°C and 75°C). As a result, the PP composites of the same thickness absorbed more energy than PA6 composites. The amount of absorbed energy of PP and PA6 composites decreased with temperature.

    AtıfScopus7WoS6OpenAlex6
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  • MakaleYalnız künye2019Scopus SJRQ3
    Determination of antioxidant capacity using different acidified solvents and element contents of Allium tuncelianum: A regional and varietal study on endemic edible garlic

    Karaaslan, Nagihan M.; Ince, Muharrem; Kaplan Ince, Olcay; Goksin Karaaslan, Merve

    Allium tuncelianum (Tunceli garlic), an endemic and threatened plant species in the Tunceli province of Eastern Turkey, is an important native source for local people. The antioxidant activities of the acidified extracts of water, acetonitrile, methanol, and ethanol of Allium tuncelianum were investigated using five antioxidant capacity tests. The results indicated that methanol extract efficiencies of garlic samples using the ABTS, CUPRAC, and reducing power capacities were higher than the other extracts. Water extract and acetonitrile extract values were highest for total phenolic content and metal chelating activities, respectively. Moreover, the element contents such as calcium (Ca), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), and zinc (Zn) of Allium tuncelianum samples digested by microwave and ashing ovens were determined by flame atomic absorption spectrophotometry and the results were compared statistically. The Ca, Cu, K, Mg, and Zn concentrations using the microwave method were found to be higher than the ashing procedure. However, the Fe, Mn, and Na concentrations using the ashing method were found to be higher than those using the the microwave protocol.

    • SDG 2 · Açlığa Son
    AtıfScopus7WoS6OpenAlex7
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  • MakaleYalnız künye2019Scopus SJRQ1
    Elimination of a measurement problem: A robust prediction model for missing eigenvector value to assess earthquake induced out-of-plane failure of infill wall

    Onat, Onur; Yön, Burak

    One of the effective methods to assess local or global behavior of structural system is to perform shake table experiment. The biggest challenge of all experiments, either shake table or others, are missing data during the experiments due to removed instruments. This problem is arose especially during the out-of-plane tests. This problem is named as “Measurement” problem. This paper is focused on detection the measurement problem and solving this problem by using Adaptive-Network Based Neuro Inference System (ANFIS). Definition of the problem is briefly missing out-of-plane eigenvector value during the implementation of a shake table experiments on a full scale one bay one storey reinforced concrete structural system. For this aim, two shake table experiments were performed with reinforced concrete frame (RCF)and infill wall at the National Civil Engineering Laboratory (LNEC)Portugal. The out-of-plane failure of infill wall was assessed under combined bidirectional seismic load. Shake table experiments were conducted on two types of specimens. One of them is Unreinforced Brick Infill Wall (URBIF)composed of single layer 22 cm thick brick. The other is single layer 22 cm thick Infill Wall with Bed Joint Reinforcement solution (IwBJR). Both specimens were made of a single-layer brick infill wall enclosure with the RCF. Bed joint reinforcement term refers horizontal bed joint reinforcement as a strengthening technique. Shake table experiments were performed on each specimen at four stages. After third level of earthquake load, the accelerometers were removed on the wall to prevent damage to them. The removal of these instruments results in missing data. The missing eigenvector values were predicted with a robust Adaptive-Network Based Neuro Inference System (ANFIS)model to present failure mode of infill wall. The estimation quality was tested with R2, Mean Absolute Percentage Error (MAPE), Mean Square Error (MSE)and Root Mean Square Error (RMSE)among with available data. The results of the quality indicator of R2 are 0.999 for URBIF model and 0.997 for IwBJR model, respectively. Moreover, rest of the indicator results are less than %1. The proposed approach is reliable on the base of quality indicator. Moreover, this study can be used for seismic engineering to predict eigenvector values to see local behavior of infill wall and mode shape evolution to determine which mod prone for partial and total collapse of infill wall.

    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
    AtıfScopus12WoS11OpenAlex10
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  • MakaleAçık Erişim2020
    Diauehi and Urartian Tribal Centers in the Context of the Urartian Administration System; [Urartu Kralligi'nin Idari Sistemi Baglaminda Diauehi ve Urartu Aşiret Merkezleri]

    Danişmaz, Harun; Konyar, Erkan

    The Diauehi region, located in the northwest border of Urartian Kingdom, is called the Upper Aras basin nowadays. The Urartian remains in the Upper Aras basin have been found in the Hasankale/Pasinler, Marifet and Yoǧunhasan fortresses. Apart from these settlements, to the east of the basin are the Hamamli and Hasankale inscriptions, to the south are the Avnik, Delibaba and Yazilitaş inscriptions, and the Süngütaş inscription is located on the route to the north. From its early years onwards, the Urartian Kingdom tried to transform the Diauehi region through military campaigns and administrative arrangements. However, this transformation appears to have been different from the center of the kingdom, the Lake Van Basin, where the majority of the royal cities we are located. Instead of building new cities in the region, the kingdom's strategy was focused on conducting military campaigns to weaken the existing tribes and allying with the powerful ones. During the military campaigns dating to the early years of the kingdom, the tribe leaders who were also named as kings paid a tribute and accepted the authority of Urartians.

    AtıfScopus1WoS1OpenAlex1
    ScopusWeb of ScienceTR Dizinİncele
  • MakaleAçık Erişim2018Scopus SJRQ3
    The protective effects of chrysin and flunixin meglumine against excess copper in male rats

    Seven, Pinar Tatli; Baykalir, Burcu Gül; Seven, Ismail; Ak, Tuba Parlak; Başak, Neşe; Güllüoglu, Hakan

    Thirty-six Sprague Dawley male rats were housed in individual cages and randomly divided into six groups: Control, copper sulfate (Cu; 500 ppm body weight (BW)/day), flunixin meglumine (FM; 2.2 ppm BW/day), chrysin (chrysin; 50 ppm BW/day), copper sulfate + FM (Cu + FM; 500 ppm BW/day of copper sulfate and 2.2 ppm BW/day of FM), and copper sulfate + chrysin (Cu + Chrysin; 500 ppm BW/day of copper sulfate and 50 ppm BW/day of chrysin). Feed intake (FI) in the Cu + Chrysin group significantly increased in comparison with that of the Cu group (P < 0.01). Cu excess significantly increased malondialdehyde, indicating oxidative stress. Chrysin and FM administration significantly decreased malondialdehyde levels and increased the superoxide dismutase and catalase activities in the liver and kidney tissues (P < 0.001). Serum TNF-α levels were significantly lower in the Cu + FM and Cu + Chrysin groups in comparison to the Cu group (P < 0.001). It was seen that FM and chrysin treatments alleviated degeneration, necrosis, and apoptosis in the liver and kidney tissues of the Cu-treated rats. Chrysin appeared to ameliorate the adverse effects on FI and liver and kidney tissues by scavenging where the free radicals are located and increasing the activity of antioxidants.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    AtıfScopus8WoS7OpenAlex9TR Dizin2
    ScopusWeb of ScienceTR Dizinİncele
  • MakaleYalnız künye2018Scopus SJRQ2
    Microbial Sorption of Uranium Using Amycolatopsis sp. K47 Isolated from Uranium Deposits

    Celik, Fatih; Camas, Mustafa; Kyeremeh, Kwaku; Sazak Camas, Anil

    The increasing contamination of soils, sediments, and water with heavy metals through natural and industrial processes is a worldwide problem. Mining processes produce tons of material contaminated with radionuclides such as U and different heavy metals such as Cd, Ni, and Pb. U(VI) adsorbs strongly on bacteria, exhibiting pH-dependent adsorption behavior that is caused by a range of uranyl surface complexes on bacteria cell walls. The Amycolatopsis sp. K47 was isolated from Manisa Koprubasi Kasar open-cast uranium mine and identified for the first time. Using the batch adsorption method, the biosorption potential of this microbe was investigated by studying the effects of changes in pH (1–10), biomass dose (0.1–5 g/l), initial uranium metal concentration (5–200 mg/l), contact time (5–180 min), and temperature (20–60 °C). Interpretation of FTIR data obtained for both the uranium loaded and unloaded Amycolatopsis sp. K47 biomass showed the presence of carboxylic acid, hydroxyl, and amide functional groups that could interact with uranium ions. Scanning electron microscopy images demonstrated that uranium was intensely adsorbed on the microbial biomass surface. The sorption isotherms were investigated by analysis of the Langmuir, Freundlich, and Dubinin–Radushkevich (D–R) models. The Langmuir isotherm model was found to show the best fit for the experimental data obtained. Furthermore, thermodynamic parameters, such as ΔH°, ΔS°, and ΔG°, were calculated using adsorption equilibrium constant obtained from the Langmuir isotherm. The optimal experimental conditions were determined to be pH = 4, C0 = 40 ppm, t = 150 min, temp. = 40 °C, and abs. dose = 1 g/l, and the corresponding U(VI) removal efficiency was about 97 ± 2%.

    • SDG 6 · Temiz Su ve Sanitasyon
    AtıfScopus16WoS14OpenAlex15
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  • MakaleYalnız künye2020Scopus SJRQ1
    Approximate-derivative-based signalprocessing method to segment power-quality disturbances

    Akmaz, Düzgün

    The increasing complexity of power systems and the increase in power quality (PQ) data have made it necessary to develop different and simple signal-processing tools. In this study, an approximate-derivative (AD) signal-processing tool based on a simple mathematical processing approach was developed for the segmentation of PQ disturbances. Although the developed method was highly effective for the segmentation of noise-free signals, the method was unable to properly handle the segmentation of noisy signals. Thus, to mitigate this situation, a denoising method based on the Sqtwolog threshold was applied to the noisy signals. After denoising, the proposed AD method effectively performed the segmentation. Subsequently, AD and a single-level discrete wavelet transform (DWT) with Daubechies 4 mother wavelets were compared through simulations, which showed that successful results can be obtained using the proposed method. Furthermore, all simulations showed that the application of AD and single-level DWT to PQ signals under different conditions resulted in similar patterns with different amplitudes. Therefore, this study provides a different approach for analysing signal using single-level DWT.

    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
    AtıfScopus5WoS4OpenAlex5
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  • MakaleAçık Erişim2020Scopus SJRQ2
    Electrical 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.

    AtıfScopus15WoS14
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  • MakaleAçık Erişim2021Scopus SJRQ2
    Metaheuristic Approaches Integrated with ANN in Forecasting Daily Emergency Department Visits

    Pekel, Engin; Gul, Muhammet; Celik, Erkan; Yousefi, Samuel

    The overall service quality level of Emergency Departments (EDs) can be improved by accurate forecasting of patient visits. Accordingly, this study aims to evaluate the use of three metaheuristic approaches integrated with Artificial Neural Network (ANN) in forecasting daily ED visits. To do this, five performance measures are used for evaluating the accuracy of the proposed approaches, including Bayesian ANN, Genetic Algorithm-based ANN (GA-ANN), and Particle Swarm Optimization algorithm-based ANN (PSO-ANN). The outputs of this study show that the PSO-ANN model provides the most dominant performance in both the training and testing process. The lowest error is obtained with a mean absolute percentage error (MAPE) of 6.3%, Mean Absolute Error (MAE) of 42.797, Mean Squared Error (MSE) of 2499.340, Root Mean Square Error (RMSE) of 49.933, and R-squared (R2) of 0.824 on the training dataset. The lowest error with an MAPE of 6.0%, MAE of 40.888, MSE of 2839.998, RMSE of 53.292, and R2 of 0.791 is also obtained on the testing process.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    AtıfScopus7WoS5OpenAlex7
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  • MakaleAçık Erişim2018Scopus SJRQ3
    Ti doped amorphous carbon (Al/Ti-a:C/p-Si/Al) photodiodes for optoelectronic applications

    Aslan, Naim; Koç, Mümin Mehmet; Dere, Ayşegül; Arif, Bilal; Erkovan, Mustafa; Al-Sehemi, Abdullah G.; Al-Ghamdi, Ahmed A.; Yakuphanoglu, Fahrettin

    Electrochemical deposition technique was used to fabricate titanium doped amorphous carbon (Ti doped a:C) Al/Ti-a:C/p-Si/Al photodiode. The effects of illumination on the current–voltage (I–V) characteristics of the Al/a:C/p-Si/Al doped Ti diode for optoelectronic applications were investigated. The reverse current of the diode increased with the increasing illumination intensities when the bias voltage was applied. By using the forward bias I–V characteristics, the ideality factor (n) and barrier height (Φb) of Al/Ti-a:C/p-Si photodiode structure was found as 1,84 and 0,50 eV, respectively. In addition, the capacitance–voltage (C–V) and conductance–voltage (G–V) measurements of the diode were studied in the frequency range of 100 kHz–600 kHz. The measured values of the capacitance decreased with the increasing frequency. The photoelectrical properties of Al/Ti-a:C/p-Si/Al device indicates that the photodiode investigated in this paper has great potential to be used in optoelectronic device applications and in industry.

    AtıfScopus41OpenAlex43
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