Yayınlar
Koleksiyondaki öğeler
- MakaleYalnız künye2018Scopus SJRQ2Effects of voltage gradient and fat content on changes of electrical conductivity of frozen minced beef meat during ohmic thawing
Cevik, Mutlu; Icier, Filiz
Frozen minced beef meat samples having different fat contents of 2, 10, and 18% were thawed until their center temperature reached −1 °C in the ohmic thawing system. Ohmic thawing was conducted by applying different voltage gradients (10, 13, and 16 V/cm) at ambient temperature of 4 ± 0.5 °C. Effective electrical conductivity (EEC) values of the samples at −1 °C were 0.5774 ± 0.0558, 0.4231 ± 0.0510, and 0.3933 ± 0.0693 S/m for 2, 10, and 18% fat contents, respectively. The change of effective electrical conductivity with temperature was linear for temperature range of −18 °C/−9.5 °C while it was exponential for temperature range of −9.5 °C/−4 °C. Above −4 °C, the polynomial model was best model describing the change of EEC with temperature. Ohmic thawing process could be applied as an alternative novel technology for thawing of meat and meat products. It is thought that the results of present study would contribute valuable information to open literature. Practical applications: Researchers have given attention on investigation of alternative thawing methods for foods in recent years. Ohmic thawing has high energy efficiency, causes low drip loss and does not produce any waste water. Since it is controlled by heat generation caused due to passing of alternative current through food, the information on change of its electrical conductivity is crucial. The minced beef sample has heterogeneous structure such as muscle, connective, and adipose tissues. Thus, its effective electrical conductivity (EEC) varies depending on its composition. In this study, the relations between temperature and EEC of minced beef samples having different fat contents were determined for four different temperature ranges existed during ohmic thawing at different voltage gradients. EEC was very low at temperatures below −4 °C, and then it sharply increased above this temperature. Results of present study would give valuable information to food industry for setting up industrial scale ohmic thawing systems for meat and meat products.
AtıfScopus52WoS47
İncele - MakaleYalnız künye2020Scopus SJRQ1Study on model uncertainty of water source heat pump and impact on decision making
Zhang, Ying; Akkurt, Nevzat; Yuan, Jiaqi; Xiao, Ziwei; Wang, Qianjiang; Gang, Wenjie
Water source heat pump systems are widely used for cooling and heating due to high efficiency. The energy source can be surface water or underground water. Accurate modeling of water source heat pump systems is the basis for performance prediction, design and control optimization. However, various heat pump models are available to predict the system performance and results obtained can be very different under different models due to the model uncertainty. Without considering these uncertainties, the performance of water source heat pump systems would be overestimated or underestimated and the decision making would be affected. This paper attempts to quantify the model uncertainty of water source heat pump and its impact on the system performance. Thirteen commonly-used models are selected and validated using the manufacture data. By importing these models into the water source heat pump system, the impact of heat pump model uncertainty on the system performance is quantified. It shows that the model uncertainty can result in a deviation of up to 30% in the annual energy consumption. The energy saving potential of water source heat pump systems can vary from -18.43% to 14.78% compared with the chillers & boiler in the hot summer and cold winter area. The priority of water source heat pump systems is also controversial. The difference in the annual average coefficient of performance of the system can be up to 1.22. It demonstrates that the model uncertainty of water source heat pumps affects the system performance significantly and should be taken into account in building energy prediction and design optimization. The models considering the correction of part load ratio are recommended.
AtıfScopus40WoS34OpenAlex45İncele - MakaleAçık Erişim2019Scopus SJRQ1Convolutional neural networks for multi-class brain disease detection using MRI images
Talo, Muhammed; Yildirim, Ozal; Baloglu, Ulas Baran; Aydin, Galip; Acharya, U Rajendra
The brain disorders may cause loss of some critical functions such as thinking, speech, and movement. So, the early detection of brain diseases may help to get the timely best treatment. One of the conventional methods used to diagnose these disorders is the magnetic resonance imaging (MRI) technique. Manual diagnosis of brain abnormalities is time-consuming and difficult to perceive the minute changes in the MRI images, especially in the early stages of abnormalities. Proper selection of the features and classifiers to obtain the highest performance is a challenging task. Hence, deep learning models have been widely used for medical image analysis over the past few years. In this study, we have employed the AlexNet, Vgg-16, ResNet-18, ResNet-34, and ResNet-50 pre-trained models to automatically classify MR images in to normal, cerebrovascular, neoplastic, degenerative, and inflammatory diseases classes. We have also compared their classification performance with pre-trained models, which are the state-of-art architectures. We have obtained the best classification accuracy of 95.23% ± 0.6 with the ResNet-50 model among the five pre-trained models. Our model is ready to be tested with huge MRI images of brain abnormalities. The outcome of the model will also help the clinicians to validate their findings after manual reading of the MRI images.
AtıfScopus276OpenAlex301
İncele - MakaleAçık Erişim2019Scopus SJRQ2Classification of multiple power quality events via compressed deep learning
Liu, Hui; Hussain, Fida; Yue, Shen; Yildirim, Ozal; Yawar, Sheikh Junaid
This paper presents a recently established compressed sensing (CS) and sparse autoencoder (SAE) based on deep learning (DL) method for classification of single and multiple power quality disturbances (PQDs). The CS technique is paying considerable attention in recent years due to below sampling rate comparatively Nyquist sampling. Initially, the CS technique is applied to extract the features of PQD waveforms. The extracted features are applied as inputs to the sparse autoencoder based on DL for classification of nine single and 22 combined classes of PQDs. The DL helps to remove a redundant feature and improves classification performance. Finally, backpropagation is applied to fine-tune the entire network. The effectiveness of the proposed algorithm has been tested with more than 6580 numbers of real and synthetic single and multiple PQD data, and the results are recorded. High correct classification rate is obtained with noise and without noise level. Noise level was considered from 20 to 50 dB. The performance of the proposed technique has been assessed by comparing the results against recently reported methods. Results show that the proposed CS- and SAE-based DL algorithms can be efficiently used for single and multiple PQDs classifications.
AtıfScopus28OpenAlex28İncele - MakaleAçık Erişim2019Scopus SJRQ3Fuzzy-logic-based robust speed control of switched reluctance motor for low and high speeds
Omaç, Zeki
Switched reluctance motor (SRM) is operated at high magnetic saturation to generate large torque. The flux linkage of SRM is a nonlinear function with phase current and rotor position because of the high magnetic saturation. Also, the performance of the speed controller for the SRM driver system can be negatively affected by noise, disturbances, and inertia of load torque. Therefore, the fuzzy speed controller for the SRM driver system was developed in this study. In addition, a dynamic model of SRM was simulated in Matlab/Simulink software. Based on the results obtained in this study, the speed of the SRM was controlled over a wide range of speeds including low and high speeds by the fuzzy speed controller. Furthermore, in simulation, the rotor speed was simulated depending on the reference speed. Moreover, the speed of the SRM was experimentally tested using the DS1103 Ace kit. Finally, simulation results were compared with experimental results and they were found to be consistent with each other.
AtıfScopus10WoS5OpenAlex9TR Dizin3
İncele - MakaleAçık Erişim2018Scopus SJRQ2Novel complex and hyperbolic forms to the strain wave equation in microstructured solids
Baskonus, Haci Mehmet; Sulaiman, Tukur Abdulkadir; Bulut, Hasan
This study applies the powerful sine-Gordon expansion method in acquiring some new solutions to the strain wave equation in micro-structured solids arising in mathematical physics. The strain wave equation in micro-structured solids is used in modelling wave propagation in micro-structured materials. We successfully acquire some new solitary wave solutions with hyperbolic function structure. By taking some suitable values of parameters involved in the solutions, we plot the 2D, 3D and contour graphs of all the obtained solutions in this study.
AtıfScopus34WoS34OpenAlex36İncele - MakaleYalnız künye2020Scopus SJRQ2Seismic vulnerability assessment of RC buildings according to the 2007 and 2018 Turkish seismic codes
Yön, Burak
Fragility curves are useful tools to estimate the damage probability of buildings owing to seismic actions. The purpose of this study is to investigate seismic vulnerability of reinforced concrete (RC) buildings, according to the 2007 and 2018 Turkish Seismic Codes, using fragility curves. For the numerical analyses, typical five-and seven-storey RC buildings were selected and incremental dynamic analyses (IDA) were performed. To complete the IDAs, eleven earthquake acceleration records multiplied by various scaling factors from 0.2g to 0.8g were used. To predict nonlinearity, a distributed hinge model that involves material and geometric nonlinearity of the structural members was used. Damages to confined concrete and reinforcement bar of structural members were obtained by considering the unit deformation demands of the 2007 Turkish Seismic Code (TSC-2007) and the 2018 Turkey Building Earthquake Code (TBEC-2018). Vulnerability evaluation of these buildings was performed using fragility curves based on the results of incremental dynamic analyses. Fragility curves were generated in terms of damage levels occurring in confined concrete and reinforcement bar of structural members with a lognormal distribution assumption. The fragility curves show that the probability of damage occurring is more according to TBEC-2018 than according to TSC-2007 for selected buildings.
AtıfScopus16WoS12OpenAlex7İncele - MakaleAçık Erişim2020Scopus SJRQ3Removal of tetracycline antibiotic by Lemna gibba L. from aqueous solutions
Topal, Murat; Öbek, Erdal; Uslu Şenel, Gülşad; Arslan Topal, E. Işıl
In this study, the efficiency of Lemna gibba L. on tetracycline (TC) removal from the solutions prepared at various initial TC concentrations (50, 100 and 300 µg/L) was investigated. The study was conducted in the reactors planted with Lemna gibba L. plants. Lemna gibba L. plants in the reactors were harvested at various hydraulic retention times. Then, the concentrations of TC were determined by using LC/-MS-MS. The maximum removal efficiencies for the TC50, TC100 and TC300 in the planted reactors were 99.8 ± 4.1; 99.9 ± 4.9 and 99 ± 4.9%, respectively. The harvesting times for Lemna gibba L. at TC50, TC100 and TC300 concentrations were determined to be 12, 8 and 12 hours, respectively. First-, second- and pseudo-first-order kinetics are determined in the planted reactors (with Lemna gibba L.). According to the study results, second-order kinetics were obtained at TC50, TC100, TC300 concentrations. As a result, the Lemna gibba L. plant can be used as an alternative treatment method to other advanced treatment methods and it can be done with a cheap method by adapting to existing treatment plants. Lemna gibba L. plants can be used to remove pollutants by applying them to polluted lakes and water bodies.
AtıfScopus12OpenAlex11İncele - MakaleYalnız künye2020Scopus SJRQ1Techno-economic analyses of multi-functional liquid air energy storage for power generation, oxygen production and heating
Wang, Chen; Akkurt, Nevzat; Zhang, Xiaosong; Luo, Yimo; She, Xiaohui
Liquid air energy storage (LAES) is increasingly popular for decarbonizing the power network. At off-peak time, ambient air after purification is liquefied and stored; at peak time, the liquid air is discharged to generate power. One of the key challenges for the LAES system is the lower economic benefit as peak electricity is usually the only source of income, leading to a longer payback period of ~15 years. To address this issue, this paper, for the first time, proposes a multifunctional LAES system, which not only generates peak electricity but also provides pure oxygen and heating. The proposed system is composed of an air separation unit (ASU), a nitrogen liquefaction unit (NLU) and a power generation unit (PGU). Thermodynamic and economic analyses are carried out on the proposed system. Compared with the baseline LAES system (NLU + PGU), the multifunctional LAES system has a lower round trip efficiency of ~0.39 due to the extra electricity consumption by the ASU. However, it shows a much better economic performance with additional benefits from pure oxygen and heating. In a project life-span of 30 years, the multifunctional LAES system (10 MW/80 MWh) has a short payback period of ~5.7 years. Furthermore, it has a savings-to-investment ratio of 3.12, which is ~153% higher than that of the baseline LAES system. Investigation on the system operation strategy suggests that the ASU should operate at full time. The proposed system provides a feasible way to improve the economic benefits of the LAES system, thus promoting its wide applications.
AtıfScopus82OpenAlex86İncele - MakaleYalnız künye2019Scopus SJRQ3Assessment of the mass attenuation coefficients of granite, basalt, andesite and tuff stones with the Geant4 model of a high-purity germanium detector
Aşkin, A.; Dal, M.
In this work, the radiation shielding properties of various natural stones, such as granite, basalt, andesite and tuff, were determined by using Monte-Carlo simulations performed with the Geant4 model of a high-purity germanium (HPGe) detector. Mass attenuation coefficients were calculated for γ-ray energies of 80.9, 140.5, 356.5, 661.6, 1173.2 and 1332.5 keV and for the sample thicknesses between 1 and 7 cm. The results of this study indicate that the stone samples have lower mass attenuation values varying in the range from - 28.8 % to - 3.7 % compared to lead. Among the measured stone samples, the mass attenuation values of tuff stone are closest to lead (above 661.6 keV).
AtıfScopus7WoS6OpenAlex8İncele - MakaleAçık Erişim2018Scopus SJRQ3Optical solitons and other solutions to the conformable space–time fractional complex Ginzburg–Landau equation under Kerr law nonlinearity
Sulaiman, Tukur Abdulkadir; Baskonus, Haci Mehmet; Bulut, Hasan
This study reveals the dark, bright, combined dark–bright, singular, combined singular optical solitons and singular periodic solutions to the conformable space–time fractional complex Ginzburg–Landau equation. We reach such solutions via the powerful extended sinh-Gordon equation expansion method (ShGEEM). Constraint conditions that guarantee the existence of valid solitary wave solutions are given. Under suitable choice of the parameter values, interesting three-dimensional graphs of some of the obtained solutions are plotted.
AtıfScopus37İncele - MakaleYalnız künye2020Traces of late quaternary glaciations and paleoclimatic interpretation of Mount Akdağ (Alanya, 2451 m), Southwest Turkey
Bayrakdar, Cihan; Çılğın, Zeynel; Keserci, Ferhat
Mount Akdağ, located 25 km northeast of Alanya (2451 m above sea level a.s.l.), and largely made up of carbonates, is one of the mountains exposed to Late Quaternary glaciation in the Western Taurus Mountains. Although today, there are no modern glaciers, the traces of the Late Quaternary glaciers and rock glaciers are still fresh. In this study, geomorphological features related to the glaciations in Mount Akdağ, which were not previously reported in the literature, were first identified from satellite images, and then verified by field studies. The geomorphological development of Mount Akdağ during the Quaternary was explained by considering its climatic and karstic characteristics. For this purpose, spatial data obtained from field studies, unmanned aerial vehicles and meteorological stations were analysed using geographic information systems. Akdağ is directly open to humid air masses coming from the SW sector over the Mediterranean Sea, resulting in heavy orographic precipitation that encouraged the growth of glaciers. In addition, glacier reconstruction and pELA estimates have been made to contribute to the interpretation of glacial geomorphology. The pELA in Mount Akdağ was calculated with the AABR ratio of 1.69, and was found to be around 2030 m a.s.l. More than 15 cirques and a 6.5 km long glacial valley in Mount Akdağ indicate the presence of glaciers. Reconstruction of the paleoglaciers shows that the lowest altitude reached was 1410 m a.s.l. At their maximum extent glaciers covered an area of ~ 14 km2, with a volume of ~ 1 km3 and had an average thickness of 60 m with a maximum glacier thickness of ~ 200 m.
AtıfScopus19OpenAlex23İncele - BildiriYalnız künye2018Control of fluid flow around a square prism by fluid injection at low Reynolds number
Flrat, Erhan
The two-dimensional wake structure behind a fixed, rigid square prism with fluid injection from the single, relatively narrow slot (h/H=0.1) has been computed at low Reynolds number (Re=ρ·U∞·H/μ=100 based on the side length of the prism and freestream velocity) using a finite volume method (FVM). Injection surface (i.e. front and rear) and injection rate (from IR=UJ/U∞=0 to 3 by 0.2 step) are the key parameters that determine the aerodynamic and flow characteristics. Two flow patterns for the prism with front jet and four flow patterns for the prism with rear jet were identified with respect to IR. Flow patterns were associated with changes in flow and aerodynamic characteristics.
AtıfOpenAlex1İncele - MakaleAçık Erişim2020Scopus SJRQ3Biosorptive removal of eriochrome black-T using agaricus campestris: Parameters optimization with response surface methodology
Alp, Hevidar; Ince, Muharrem; Ince, Olcay Kaplan; Onal, Ali
In this study, Eriochrome Black T (EBT) removal from aqueous media by Agaricus campestris (AC) which is an eco-friendly biosorbent was investigated using a central composite design (CCD) combined with response surface methodology. The CCD was chosen as the statistical prediction method to reduce the number of experiments which, in turn, will directly save time and chemicals. To opti-mize the process, various experimental independent variables such as the pH of the solution, contact time, adsorbent dosage and temperature were selected. The optimal experimental conditions were obtained as 6.5, 30°C, 20 min and 20 mg, for solution pH, temperature, contact time and adsorbent dosage, respectively. Under these optimized conditions, maximum EBT (100 mg L–1 initial concentra-tion) removal efficiency was calculated as 64.2 mg g–1. The independent variables and their interaction significance were checked using analysis of variance and it was found that the EBT biosorption on AC was highly significant (p < 0.001). The results were justified by the relatively high correlation coefficients (R2 = 0.9967) of the statistical prediction. The EBT biosorption was confirmed by fourier transform infrared spectroscopy (FTIR) analysis monitoring the functional groups during EBT biosorption on AC. This was the first report on the parameter optimization of EBT biosorp-tion using AC in an experimental design. The used biosorbent was characterized by FTIR, scanning electron microscope coupled with energy dispersive spectrometer and thermogravimetric analysis. The proposed biosorption process efficiently removed EBT, present in various aqueous mediums and can be used in industrial processes.
AtıfScopus17WoS12İncele - MakaleAçık Erişim2020Scopus SJRQ2An integrated approach of best-worst method (bwm) and triangular fuzzy sets for evaluating driver behavior factors related to road safety
Moslem, Sarbast; Gul, Muhammet; Farooq, Danish; Celik, Erkan; Ghorbanzadeh, Omid; Blaschke, Thomas
Driver behavior plays a major role in road safety because it is considered as a significant argument in traffic accident avoidance. Drivers mostly face various risky driving factors which lead to fatal accidents or serious injury. This study aims to evaluate and prioritize the significant driver behavior factors related to road safety. In this regard, we integrated a decision-making model of the Best-Worst Method (BWM) with the triangular fuzzy sets as a solution for optimizing our complex decision-making problem, which is associated with uncertainty and ambiguity. Driving characteristics are different in different driving situations which indicate the ambiguous and complex attitude of individuals, and decision-makers (DMs) need to improve the reliability of the decision. Since the crisp values of factors may be inadequate to model the real-world problem considering the vagueness and the ambiguity, and providing the pairwise comparisons with the requirement of less compared data, the BWM integrated with triangular fuzzy sets is used in the study to evaluate risky driver behavior factors for a designed three-level hierarchical structure. The model results provide the most significant driver behavior factors that influence road safety for each level based on evaluator responses on the Driver Behavior Questionnaire (DBQ). Moreover, the model generates a more consistent decision process by the new consistency ratio of F-BWM. An adaptable application process from the model is also generated for future attempts.
AtıfScopus96WoS83OpenAlex93İncele - MakaleAçık Erişim2017Scopus SJRQ2On the novel wave behaviors to the coupled nonlinear Maccari's system with complex structure
Baskonus, Haci Mehmet; Sulaiman, Tukur Abdulkadir; Bulut, Hasan
In this paper, we seek for the new soliton solutions to the coupled nonlinear Maccari's system by using sine-Gordon expansion method. Sine-Gordon expansion method is based on sine-Gordon Eq. (2.1) and a travelling wave transformation. We obtain new complex hyperbolic functions solutions to this system with help of Wolfram Mathematica 9, we also plot 3-dimensional and 2-dimensional graphics to some obtained solution using the same program in Wolfram Mathematica 9. Finally, we submit a comprehensive conclusions.
AtıfScopus83WoS85OpenAlex90İncele - MakaleAçık Erişim2019Scopus SJRQ3Possible indices for the assessment of ecological stream quality based on macroinvertebrates in Euphrates tributaries (Turkey)
Gültekin, Zuhal; Hellmann, Claudia; Aydin, Rahmi; Winkelmann, Carola
The aim of this study was to support the development of ecological stream quality assessment tools in order to provide a method for sustainable water management in Turkey. Therefore, we present two new or adapted indices based on benthic invertebrates. To develop and adapt the indices, 17 streams were studied and separated into three quality classes, which were supported by four community indices (EPT [%], EPTCBO [%], number of Individuals, evenness), and 23 taxa were identified as indicators for these three quality classes. As a first biological index, we adapted the Hindu Kush-Himalaya biotic score (HKHbios) to the Euphrates catchment by establishing a new and ecoregion-specific score list (Euph-Scores) by scoring 93 taxa depending on their distribution between the quality classes. Based on these scores, several average score per taxon values (ASPT value) were calculated. All ASPT values of the Euph-Scores separated the quality classes significantly. After a comparison of the different ASPT values we recommend to use the weighted ASPT, because the weighting enabled a sharper differentiation between the quality classes and named it Euphrates Biotic Score (EUPHbios). As a second biological index, we propose the proportion of habitat specialists. To calculate this index, a habitat score was developed by analysing the habitat preferences of several benthic invertebrates. Habitat score values were assigned to the 20 most common taxa from the streams in the best quality class (natural streams). The proportion of habitat specialists, identified using the new habitat score, differed significantly between the three quality classes, with higher values in natural streams than in polluted streams. In the light of the results, the presented methods appear to be suitable for developing a multi-metric index for assessment programs for the mountainous regions of the Middle East.
AtıfScopus8OpenAlex10İncele - BildiriAçık Erişim2020Speed Control of DC Motor under Load Condition Using Single Phase Matrix Converter
Boydak, Merve; Orhan, Ahmet; Caliskan, Abuzer
In this study, speed control of a separately excited DC motor was performed using Single Phase Matrix Converter (SPMC). The driver circuit that operates SPMC in buck-boost mode was used. The DC motor was first run without any controller and the change in speed was observed in the case of loading. Then, the motor was run by using PI controller and speed of the motor was kept constant during loading. Switches in the single-phase matrix converter are switched using Sinusoidal Pulse Width Modulation (SPWM) technique. MATLAB/Simulink was used for simulation.
AtıfScopus1İncele - MakaleYalnız künye2019Scopus SJRQ3Palliative effect of curcumin on doxorubicin-induced testicular damage in male rats
Aksu, Emrah Hicazi; Kandemir, Fatih Mehmet; Yıldırım, Serkan; Küçükler, Sefa; Dörtbudak, Muhammed Baheeddin; Çağlayan, Cüneyt; Benzer, Fulya
This study aimed to investigate the effect of curcumin (CUR) on doxorubicin (DOX)-induced testicular damage in male rats. Thirty-five adult male Wistar rats were used. Control group was received saline for 7 days. CUR group received CUR for 7 days. DOX group received single dose DOX on the 5th day. DOX+ CUR-100 group received 100 mg/kg/day CUR for 7 days and DOX injection on the 5th day. DOX + CUR-200 group received 200 mg/kg/day CUR for 7 days and DOX injection on the 5th day. DOX treatment decreased in sperm motility rate, live sperm percentages, cellular antioxidants, and increased malondialdehyde (MDA) levels, necrosis, degenerations, and slimming in seminiferous tubules, and DNA damages in testes by inducing oxidative stress. CUR treatment mitigated significantly these side effects when compared with DOX group in a dose-dependent manner. In conclusion, CUR treatment can be used in the mitigation of DOX-induced testicular toxicity.
AtıfScopus56WoS51OpenAlex68İncele - MakaleAçık Erişim2018Scopus SJRQ3A New Application Based on GPLVM, LMNN, and NCA for Early Detection of the Stomach Cancer
Korkmaz, Sevcan Aytaç; Esmeray, Furkan
In this article, speeded-up robust features (SURF) for each image have been calculated. Discrete Fourier transform (DFT) method has been applied to these SURF. High dimensions of these SURF–DFT feature vectors are reduced to low dimensions with large-margin nearest neighbor (LMNN), Gaussian process latent variable models (GPLVM), and neighborhood component analysis (NCA). When size reduction process was done, effect on the GPLVM, LMNN, and NCA of the 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 feature numbers has been examined. These features are classified by naive Bayes (NB) classifier. Thus, SURF_DFT_GPLVM_NB, SURF_DFT_NCA_NB, and SURF_DFT_LMNN_NB methods for gastric histopathological images have been developed. Classification results obtained with these methods have been compared. According to the obtained results, the highest classification result was obtained as 90.24% by using 4 features by SURF_DFT_GPLVM_NB method for second group images.
AtıfScopus5WoS4OpenAlex7İncele
