05. Fakülteler

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Citation - WoS: 5
Citation - Scopus: 4
12th June 2017 Offshore Karaburun-Lesvos Island Earthquake Coseismic Deformation Analysis Using Continuous Gps and Seismological Data
(SCIENTIFIC TECHNICAL RESEARCH COUNCIL TURKEY-TUBITAK, 2021) Yıldız, Hasan; Çırmık, Ayça; Pamukçu, Oya; Özdağ, Özkan Cevdet; Gönenç, Tolga; Kahveci, Muzaffer
Understanding the tectonic mechanism generated by the earthquakes and faults is possible only if the preseismic, coseismic and postseismic crustal deformation related to the earthquakes is determined properly. By the analysis of continuous GPS (CGPS) coordinate time series, it is possible to estimate the crustal deformation. Besides, accelerometer records at strong motion stations (SMSs) may support the CGPS-based estimates. In this study, CGPS coordinate time series were analyzed in comparison with the accelerometer records for clarifying the coseismic deformation caused by the earthquake occurred in the surrounding of Lesvos fault located in the northern part of Karaburun within the active mechanism that controls the area where the earthquakes occurred during June 2017 on the offshore Karaburun. The activity of this fault continued throughout June 2017 until the time when the main shock (12th June 2017, M-W = 6.2) occurred. We analyzed CGPS coordinate time series of AYVL and CESM and DEUG stations to determine the coseismic deformation due to the offshore Karaburun-Lesvos Island earthquake using the empirical mode decomposition (EMD) method. Besides, the EMD method results were compared with the accelerometer records obtained from the SMSs close to the CGPS stations and CGPS-based results were found to be consistent with the accelerometer records. Additionally, the horizontal displacements were calculated by Coulomb 3.3 software using different focal plane solutions and compared with CGPS-based results. Consequently, it is suggested an integrated use of CGPS and strong motion accelerometer networks for the joint assessment of the crustal deformation and for the cost-effective use of existing observation networks as well as for the establishment of future observation networks at lower cost.
21. Yy. Barınma Eğilimlerinde Minimalist Bir Yaklaşım "tiny House" Yaşam Modeli
(NEÜ Yayınları, 2022) Aköz Çevrimli, Begüm; Çevrimli, S. Cevat; Yılmaz Çakmak, Bilgehan
Citation - WoS: 11
Citation - Scopus: 15
Accuracy Assessment of Dems Derived From Multiple Sar Data Using the Insar Technique
(SPRINGER HEIDELBERG, 2021) Karabörk, Hakan; Makineci, Hasan Bilgehan; Orhan, Osman; Karakuş, Pınar
In this study, digital elevation models (DEMs) derived from AlosPalsar data (Japanese Space Agency-JAXA), Sentinel-1A data, and Envisat ASAR data (European Space Agency-ESA) were compared by using a global navigation satellite system (GNSS). In addition, AW3D30, SRTM, and ASTER GDEM (open-access DEMs) data were also included in the accuracy evaluation. The DEM accuracies were investigated in three different terrain types, namely a plain area, mountainous area and agricultural area, and compared at elevation values on a pixel-based. The accuracy obtained from the ALOS PALSAR satellite data was found to be more reliable for all three terrain types. The standard deviation and root mean square values were calculated and compared to each other. The results of the accuracy assessments showed that the best result for the plain area was obtained with the Sentinel-1A and SRTM data, for the mountainous area was obtained with the SRTM data and for agricultural area was obtained with the ALOS PALSAR and SRTM data.
Citation - WoS: 1
Citation - Scopus: 1
An Accurate and Novel Numerical Simulation With Convergence Analysis for Nonlinear Partial Differential Equations of Burgers-Fisher Type Arising in Applied Sciences
(Walter De Gruyter Gmbh, 2022) Kürkçü, Ömür Kuvanc; Sezer, Mehmet
In this study, the second-order nonlinear partial differential equations of Burgers-Fisher type are considered under a unique formulation by introducing a novel highly accurate numerical method based on the Norlund rational polynomial and matrix-collocation computational system. The method aims to obtain a sustainable approach since it contains the rational structure of the Norlund polynomial. A unique computer program module, which involves very few routines, is constructed to discuss the precision and efficiency of the method and these few steps are described via an algorithm. A residual function is employed in both the error and convergence analyses with mean value theorem for double integrals. The considered equations in the numerical tests stand for model phenomena arising widely in applied sciences. Graphical and numerical comparisons provide a clear observation about the consistency of the method. All results prove that the method is highly accurate, eligible, and provides the ultimate operation for aforementioned problems.
Accurate Edge Detection With Support of Reflectance Transformation Imaging
(Institute of Electrical and Electronics Engineers Inc., 2022) Kaya, Burhan; Durdu, Akif
Reflectance Transformation Imaging (RTI) is a method of photographing an object that reveals details that are invisible to the naked eye. The input of RTI consists of a series of images captured by a fixed positioned camera and each illuminated from a known and different direction by lights. Reflection Transform Imaging is widely used to produce quality models from multi-light image data. It is frequently preferred for various studies in the field of cultural heritage. For the first time in this paper, the RTI photographing method has been used outside of its traditional using way. It is used to solve the well-known problem of edge detection. Reflection transform cannot be used actively, because it is difficult to create an RTI experimental environment in daily life. However, under certain conditions, the approaches mentioned in this paper will be used in daily life, from the analysis of images in every field. In this paper, the ideas that it can be applied in every partially controlled area that needs high resolution object detection are discussed. With the method mentioned in this statement, a new approach has been proposed and proven based on RTI basics for edge and corner detections. © 2022 IEEE.
Citation - WoS: 3
Citation - Scopus: 4
Achievable Rate Analysis for Two-Way Relay Non-Orthogonal Multiple Access Systems
(IEEE, 2021) Özdemir, Özgür
This paper investigates the performance of a non-orthogonal multiple access (NOMA) based two-way relaying system where the users want to exchange independent messages with the help of a decode-and-forward relay. We consider transmission over three phases where the first and second phases are allocated to the transmissions of the users and after detection the relay applies superposition coding and transmits the network encoded symbol to the users in the third phase. Exact analytical expressions are derived to characterize the achievable average rate of the system over independent Rayleigh fading channels. Computer simulations are also presented to confirm the theoretical analysis. Analytical and simulation results show that the proposed three-phase two-way relaying scheme with NOMA outperforms the two-phase and four-phase NOMA-based two-way relaying scenarios in terms of achievable average rate.
Citation - Scopus: 1
Achievable Rate of Noma-Based Cooperative Communication Systems With Best Relay Selection Over Cascaded Rayleigh Fading Channels
(IEEE, 2020) Özdemir, Özgür
In this paper, the achievable rate analysis of NOMA-based cooperative communication systems with best relay selection is studied. The cascaded Rayleigh fading channels are considered since investigations have shown that cascaded channel structure agree better with mobile network models such as inter-vehicular communication systems. A cooperative network where a source terminal communicates with a destination directly and through a selected relay among K relays is considered and the achievable average rate of this system using NOMA is found by computer simulations. The obtained results for cascaded Rayleigh fading channels in case of decode and forward protocol have shown that the average rate is decreased as the cascading degree increases. It has been also seen that for a given cascading degree the average rate performance of the system is increased when the number of total relays is increased.
Citation - Scopus: 5
Achieving Shojinka by Integrated Balancing of Multiple Straight Lines With Resource Dependent Task Times
(Springer New York LLC, 2019) Atasagun, Y.; Kara, Y.; Can Atasagun, Gözde
The concept of Shojinka, which is an important element of Just in Time production system, is attaining flexibility on the number of workers in a workshop due to demand variations. Even though Just in Time production system adopts U-shaped line layout, traditional straight lines can be combined and balanced in an integrated manner to obtain the advantages of Shojinka. In this case, the problem, which is called Integrated Balancing of Multiple Straight Lines, arises. On the other hand, the basic assumption of assembly line balancing is that every task’s time is fixed. However, in practice, different resource alternatives such as equipment or assistant worker may be available to process a task with different times. The problem in this case is to assign tasks and resources to stations that minimise total cost. In this study, a binary integer mathematical model is presented for integrated balancing of multiple straight lines, assuming that task times are resource dependent. The proposed model is illustrated and validated using several examples. An experimental analysis is also conducted to emphasize the advantages of the integrated balancing concept, compared to the situation in which the lines are balanced independent from each other. The experimental results show that, when multiple straight assembly lines are balanced in an integrated manner with resource dependent task times, an average total cost improvement of 23.105% can be obtained compared to the independent balances of the lines. This is a significant improvement that emphasizes the importance of balancing multiple straight lines in an integrated manner, to take the advantages of shojinka and to adhere to the main philosophy of Just in Time. © Springer Nature Switzerland AG 2019.
Citation - WoS: 5
Citation - Scopus: 6
Adrenal Tumor Characterization on Magnetic Resonance Images
(WILEY, 2020) Barstuğan, Mücahid; Ceylan, Rahime; Asoğlu, Semih; Cebeci, Hakan; Koplay, Mustafa
Adrenal tumors occur on adrenal glands and are generally detected on abdominal area scans. Adrenal tumors, which are incidentally detected, release vital hormones. These types of tumors that can be malignant affect body metabolism. Both of benign and malign adrenal tumors can have a similar size, intensity, and shape, this situation may lead to wrong decision during diagnosis and characterization of tumors. Thus, biopsy is done to confirm diagnosis of tumor types. In this study, adrenal tumor characterization is handled by using magnetic resonance images. In this way, it is wanted that patient can be disentangled from one or more imaging modalities (some of them can includes X-ray) and biopsy. An adrenal tumor image set, which includes five types of adrenal tumors and has 112 benign tumors and 10 malign tumors, was used in this study. Two data sets were created from the adrenal tumor image set by manually/semiautomatically segmented adrenal tumors and feature sets of these data sets are constituted by different methods. Two-dimensional gray-level co-occurrence matrix (2D-GLCM), gray-level run-length matrix (GLRLM), and two-dimensional discrete wavelet transform (2D-DWT) methods were analyzed to reveal the most effective features on adrenal tumor characterization. Feature sets were classified in two ways: benign/malign (binary classification) and type characterization (multiclass classification). Support vector machine and artificial neural network classified feature sets. The best performance on benign/malign classification was obtained by the 2D-GLCM feature set. The best results were assessed with sensitivity, specificity, accuracy, precision, and F-score metrics and they were 99.17%, 90%, 98.4%, 99.17%, and 99.13%, respectively. The highest classification performance on type characterization was obtained by the 2D-DWT feature set as 59.62%, 96.17%, 93.19%, 54.69%, and 54.94% for sensitivity, specificity, accuracy, precision, and F-score metrics, respectively.
Adrenal Tumor Classification on T1 and T2-Weighted Abdominal Mr Images
(Institute of Electrical and Electronics Engineers Inc., 2019) Barstuğan, Mücahid; Ceylan, Rahime; Asoğlu, Semih; Cebeci, Hakan; Koplay, Mustafa
Adrenal tumors occur on adrenal glands and can be malignant. Adrenal glands consist of cortex and medulla. If cortex or medulla produce hormones extremely, the hormonal unbalance situation arises. This situation causes adrenal tumor occurrence on adrenal glands. In this study, adrenal tumors on T1 and T2-weighted MR images were classified by the SVM algorithm. Before the classification stage, different feature extraction algorithms and filtering methods were used for preprocessing. The classification results that were obtained by four different methods were evaluated on five different evaluation metrics as sensitivity, specificity, accuracy, precision, and F-score. The best classification performance was obtained with Method 2 on T1-weighted MR (Magnetic Resonance) images where the sensitivity, specificity, accuracy, precision, and F-score metrics were obtained as 99.17%, 90%, 98.4%, 99.17%, and 99.13%, respectively. © 2019 IEEE.
Citation - WoS: 9
Citation - Scopus: 11
Adrenal Tumor Segmentation Method for Mr Images
(ELSEVIER IRELAND LTD, 2018) Barstuğan, Mücahid; Ceylan, Rahime; Asoğlu, Semih; Cebeci, Hakan; Koplay, Mustafa
Background and objective: Adrenal tumors, which occur on adrenal glands, are incidentally determined. The liver, spleen, spinal cord, and kidney surround the adrenal glands. Therefore, tumors on the adrenal glands can be adherent to other organs. This is a problem in adrenal tumor segmentation. In addition, low contrast, non-standardized shape and size, homogeneity, and heterogeneity of the tumors are considered as problems in segmentation. Methods: This study proposes a computer-aided diagnosis (CAD) system to segment adrenal tumors by eliminating the above problems. The proposed hybrid method incorporates many image processing methods, which include active contour, adaptive thresholding, contrast limited adaptive histogram equalization (CLAHE), image erosion, and region growing. Results: The performance of the proposed method was assessed on 113 Magnetic Resonance (MR) images using seven metrics: sensitivity, specificity, accuracy, precision, Dice Coefficient, Jaccard Rate, and structural similarity index (SSIM). The proposed method eliminates some of the discussed problems with success rates of 74.84%, 99.99%, 99.84%, 93.49%, 82.09%, 71.24%, 99.48% for the metrics, respectively. Conclusions: This study presents a new method for adrenal tumor segmentation, and avoids some of the problems preventing accurate segmentation, especially for cyst-based tumors. (C) 2018 Elsevier B.V. All rights reserved.
Citation - WoS: 42
Citation - Scopus: 49
Adsorption of Malachite Green and Methyl Violet 2b by Halloysite Nanotube: Batch Adsorption Experiments and Box-Behnken Experimental Design
(Elsevier Ltd, 2022) Altun, Türkan; Ecevit, Hüseyin
Dyes constitute a significant part of the pollutants in industrial wastewater. In this study, halloysite nanotube (HNT) was used for adsorption of malachite green and methyl violet 2B dyes from the solution. Using batch adsorption experiments and response surface method, parameters affecting adsorption have been optimized. As a consequence of the batch experiments, after 60 min, the adsorption equilibrium state was achieved at 3 g L?1 HNT dosage, 125 mg L?1 dye concentration and natural solution pH. Temperature did not significantly affect the adsorption. The adsorption equilibrium data can be said to have fitted the Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherms well for the both dyes. The Langmuir maximum monolayer malachite green and methyl violet 2B adsorption capacities (As) of HNT are 74.95 mg g?1 and 67.87 mg g?1, respectively. Adsorption processes are more consistent with the pseudo-second-order kinetic model. In addition, both intra-particle diffusion and film diffusion are effective as rate-determining steps in adsorption. Thermodynamic calculations showed that the adsorption is exothermic and spontaneous. The regeneration of HNT after adsorption was confirmed in five cycles. By using the Box-Behnken response surface method, the parameters affecting the adsorption process were modeled, the effects of these parameters on the adsorption efficiency were expressed mathematically and the optimum operating parameters were determined. © 2022
Adsorption Properties of Red Mud, Bauxite and Red Soils in Seydişehir (konya)? Akseki (antalya) Region
(2023) Çelik Karakaya, Muazzez; Karakaya, Necati; Ruşen, Aydın; Ölçer, Derya; Edebali, Serpil
Citation - Scopus: 2
Advanced Applications of Green Materials for Gas Separation and Storage
(Elsevier, 2020) Kırbıyık Kurukavak, Çisem; Kuş, Mahmut
Extraordinary increase in global energy demand and supply, thus the environmental pollution, is one of the most important problem for today’s modern life. Gas separation and storage applications are closely related to control of the greenhouse gas and to use of clean and renewable energy. The development of green materials with desired combination properties and corresponding methods for target applications, which can minimize the environmental impact by using renewable sources has been having a growing attention over the last decades. Green and eco-friendly techniques, also called as “green chemistry, " focus on the processes and products, which reduce the use of hazardous substances and nonrenewable sources. Membrane separation, absorption, and physical adsorption for gas separation, purification, and storage are considered to be energy-efficient, low-cost, renewable, and environmental-friendly for a sustainable future. In this section, we highlight the details of these green techniques in gas separation and storage applications. © 2021 Elsevier Ltd. All rights reserved.
Citation - Scopus: 2
Advanced Applications of Green Materials in Bioelectronics Applications
(Elsevier, 2020) Yılmaz, Tuğbahan; Kuş, Mahmut
Green materials have great potential to become a primary research area for bioelectronic integration. Over the last three decades, bioelectronic applications have been getting great interest due to their low cost, flexible, nontoxic, large-volume electronic components that are sustainable, biocompatible, biodegradable, and bioresorbable. Therefore the versatility of bioelectronics applications, such as organic field-effect transistors and biosensors, promises a bright future. This chapter will highlight recent progress in the natural materials and some of their applications in bioelectronics devices. The key strategies and the forecast perspectives of this research field are also briefly summarized. © 2021 Elsevier Ltd. All rights reserved.
Citation - WoS: 50
Citation - Scopus: 55
Advanced Oxidation of Landfill Leachate: Removal of Micropollutants and Identification of By-Products
(ELSEVIER, 2021) Ateş, Havva; Argun, Mehmet Emin
Landfill leachate contains several macropollutants and micropollutants that cannot be removed efficiently by conventional treatment processes. Therefore, an advanced oxidation process is a promising step in post or pre-treatment of leachate. In this study, the effects of Fenton and ozone oxidation on the removal of 16 emerging micropollutants including polycyclic aromatic hydrocarbons (PAHs), phthalates, alkylphenols and pesticides were investigated. The Fenton and ozone oxidation of the leachate were performed with four (reaction time: 20-90 min, Fe(II) dose: 0.51-2.55 g/L, H2O2 dose: 5.1-25.5 g/L and pH: 3-5) and two (ozonation time: 10-130 min and pH: 4-10) independent variables, respectively. Among these operating conditions, reaction time played more significant role (p-value < 0.05) in eliminating di-(2-Ethylhexyl) phthalate, 4-nonylphenol and 4-tert-octylphenol for both processes. The results showed that Fenton and ozone oxidation processes had a high degradation potential for micropollutants except for the PAHs including four and more rings. Removal efficiencies of micropollutants by ozone and Fenton oxidation were determined in the range of 5-100%. Although the removal efficiencies of chemical oxygen demand (COD) and some micropollutants such as phthalates were found much higher in the Fenton process than ozonation, the degradation products occurred during the Fenton oxidation were a higher molecular weight. Moreover, the oxidation intermediates for the both processes were found as mainly benzaldehyde, pentanoic acid and hydro cinnamic acid as well as derivatives of naphthalenone and naphthalenediol. Also, acid ester with higher molecular weight, naphthalene-based and phenolic compounds were detected in the Fenton oxidation.
Citation - WoS: 8
Citation - Scopus: 12
The Aerodynamic Effects of Blade Pitch Angle on Small Horizontal Axis Wind Turbines
(Emerald Group Publishing Ltd, 2022) Kaya, Mehmet Numan; Uzol, Oguz; Ingham, Derek; Köse, Faruk; Büyükzeren, Rıza
Purpose The purpose of this paper is to thoroughly investigate the aerodynamic effects of blade pitch angle on small scaled horizontal axis wind turbines (HAWTs) using computational fluid dynamics (CFD) method to find out the sophisticated effects on the flow phenomena and power performance. Design/methodology/approach A small HAWT is used as a reference to validate the model and examine the aerodynamic effects. The blade pitch angle was varied between +2 and -6 degrees, angles which are critical for the reference wind turbine in terms of performance, and the CFD simulations were performed at different tip speed ratio values, lambda = 2, 3, 4, 5, 6, 7, 9 and 10.5 to cover the effects in various conditions. Results are examined in two different aspects, namely, general performance and the flow physics. Findings The power performance varies significantly according to the tip speed ratio; the power coefficient increases up to a certain pitch angle at the design tip speed ratio (lambda = 6); however, between lambda = 2 and 4, the more the blade is pitched downwards, the larger is the power coefficient, the smaller is the thrust coefficient. Similarly, for tip speed ratios higher than lambda = 8, the positive effect of the low pitch angles on the power coefficient at lambda = 6 reverses. The flow separation location moves close to the leading edge at low tip speed ratios when the blade is pitched upwards and the also tip vortices become more intense. In conclusion, the pitch control can significantly contribute to the performance of small HAWTs depending on different conditions. Originality/value In the literature, only very little attention has been paid to the aerodynamic effects of pitch angle on HAWTs, and no such study is available about the effects on small HAWTs. The change of blade pitch angle was maintained at only one degree each time to capture even the smallest aerodynamic effects, and the results are presented in terms of the power performance and flow physics.
Citation - WoS: 12
Citation - Scopus: 11
Aerodynamic Optimization of a Swept Horizontal Axis Wind Turbine Blade
(ASME, 2021) Kaya, Mehmet Numan; Köse, Faruk; Uzol, Oğuz; Ingham, Derek; Ma, Lin; Pourkashanian, Mohamed
The aerodynamic shapes of the blades are still of high importance and various aerodynamic designs have been developed in order to increase the amount of energy production. In this study, a swept horizontal axis wind turbine blade has been optimized to increase the aerodynamic efficiency using the computational fluid dynamics method. To illustrate the technique, a wind turbine with a rotor diameter of 0.94 m has been used as the baseline turbine, and the most appropriate swept blade design parameters, namely the sweep start-up section, tip displacement, and mode of the sweep have been investigated to obtain the maximum power coefficient at the design tip speed ratio. At this stage, a new equation that allows all three swept blade design parameters to be changed independently has been used to design swept blades, and the response surface method has been used to find out the optimum swept blade parameters. According to the results obtained, a significant increase of 4.28% in the power coefficient was achieved at the design tip speed ratio with the newly designed optimum swept wind turbine blade. Finally, baseline and optimum swept blades have been compared in terms of power coefficients at different tip speed ratios, force distributions, pressure distributions, and tip vortices.
Citation - WoS: 25
Citation - Scopus: 29
Aerogels as Promising Materials for Antibacterial Applications: a Mini-Review
(ROYAL SOC CHEMISTRY, 2021) Kaya Güzel, Gülcihan; Aznar, Elena; Deveci, Hüseyin; Martinez-Manez, Ramon
The increasing cases of bacterial infections originating from resistant bacteria are a serious problem globally and many approaches have been developed for different purposes to treat bacterial infections. Aerogels are a novel class of smart porous materials composed of three-dimensional networks. Recently, aerogels with the advantages of ultra-low density, high porosity, tunable particle and pore sizes, and biocompatibility have been regarded as promising carriers for the design of delivery systems. Recently, aerogels have also been provided with antibacterial activity through loading of antibacterial agents, incorporation of metal/metal oxides and via surface functionalization and coating with various functional groups. In this mini-review, the synthesis of aerogels from both conventional and low-cost precursors is reported and examples of aerogels displaying antibacterial properties are summarized. As a result, it is clear that the encouraging antibacterial performance of aerogels promotes their use in many antibacterial applications, especially in the food industry, pharmaceutics and medicine.
"aga Khan Mimarlık Ödüllü" Türk Projelerin Okunması
(SOSCON Social Sciences Congresses, 2018) Yıldız Kuyrukçu, Emine
1977 yılından beri üç yılda bir verilen Aga Khan Mimarlık Ödülü, İslam kültürünü başarıyla yorumlayan çağdaş tasarım, sosyal konut, toplumsal gelişim, restorasyon, yeniden kullanım ve bölgesel koruma projelerini kapsayan mimarlık ürünlerine verilen ödüldür. Mimarlığın yaşam kalitesini nasıl etkilediği Aga Khan ödülü için her zaman temel bir mesele olmuştur. İlk çıktığı yıllarda eleştirilen Aga Khan mimarlık ödülleri günümü mimarlık camiasında prestijli ve bilimsel bir ödül olarak tanımlanmaktadır. Çalışma kapsamında Türkiye genelinden Aga Khan Mimarlık Ödüllü üç proje seçilmiş; projeler üst ölçekle kurdukları ilişki, benzer yapıların üretilmesinde model olma, fonksiyon, plan şeması, çevre doku doğa ilişkisi, malzeme, yapım tekniği gibi birçok başlıkta analiz edilmiş ve ödül raporları okunmuştur. Bu çalışmaları yapmaktaki amaç bu projelerin ödül almalarını sağlayan ortak noktaların tespit edilmeye çalışılmasıdır. Sonuçta tespit edilen başlıklar tartışılmış ve çıkarımlarda bulunulmuştur.

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