Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collections
Permanent URI for this collectionhttps://hdl.handle.net/20.500.13091/3
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Book Part Warm Hydroforming(wiley, 2019-08-16) Koç, M.; Cora, Ö.N.; Halkacı, H.S.; Türköz, M.Warm hydroforming is an innovative forming technology and defined as forming of the heated tube or sheet materials by fluid pressure into the complex shapes in one step. It is a hybrid approach that integrates the advantages of both hydroforming and warm forming and offers even further benefits and opportunities. There are two main sheet hydroforming types. One of them is sheet hydroforming with die and the other one is sheet hydroforming with punch or hydromechanical deep drawing. The warm hydroforming parameters that affect the part quality and formability can be grouped under four main categories. These are material, die and tool, tribological and process and loading variables. In order to develop appropriate warm hydroforming strategies, the behavior of the materials to be formed at high temperatures should be determined. Therefore, the behaviors ofthe materials at high temperatures are determined by tensile and bulge tests. © 2020 John Wiley & Sons inc.Article Citation - Scopus: 3Heat Treatment Effect Of Hexagonal Boron Nitride Reinforced Electroless Nickel Coatings;(Turkish Energy Nuclear and Mining Research Institute, 2019-09-30) Kocabaş, M.; Yılmaz, H.; Cansever, N.In this study, surfaces of 1050 aluminium alloy were coated with hexagonal boron nitride (h-BN) reinforced electroless nickel-phosphorus (Ni-P) composite coating and the effect of heat treatment on the coating structure for 1 hour at 400°C was investigated. Composite coatings were performed in solutions which consist of three different compositions (1, 5 and 10 g/L) of h-BN. A scanning electron microscope (SEM), X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analysis were performed on the composite coatings. Additionally, surface roughness and hardness were measured and finally, electrochemical corrosion experiments were conducted in 3.5% sodium chloride (NaCl) solution. The heat treatment process has identified a transition from the amorphous structure to crystalline in the nickel matrix. The result of heat treatment, hardness values increased and the highest value of hardness (1015 ± 41 HV0.05) was achieved with the specimen coated in 10 g/L h-BN solution. In the electrochemical experiments, a reduction in corrosion resistance of the composite coatings was determined as a result of heat treatment. © 2019, Turkish Energy Nuclear and Mining Research Institute. All rights reserved.Article Citation - Scopus: 1Prediction of Specific Energy Using P-Wave Velocity and Schmidt Hammer Hardness Values of Rocks Based on Laboratory Studies Enerjinin Tahmini](Chamber of Mining Engineers of Turkey, 2019-09-01) Dursun, A.E.; Terzioǧlu, H.Specific energy has been widely used to assess the rock cuttability for mechanical rock excavation. In mechanical rock excavation processes, engineers need to predict, of machine performance based on specific energy using easy applicable, more economical and simple sample preparation methods. In this study, P-wave velocity (Vp) and Schmidt hammer hardness (RL) tests are used as predictors for prediction of specific energy, which are thought to be a practical, simple and inexpensive test. For this purpose, rock cutting and Vp and RL tests were performed on 24 different rock samples. The Vp a nd R L values were correlated with specific energy values using simple and multiple regression analysis with SPSS 15.0. As a result of this evaluation, there is a strong relation between specific energy, Vp and RL values of rocks. According to the statistical analyses, specific energy values can be reliably predicted by using Vp and RL values of rocks based on laboratories studies. © 2019 Union of Chambers of Engineers and Architects of Turkey. All rights reserved.Book Part Citation - Scopus: 11Classification of Unhealthy and Healthy Neonates in Neonatal Intensive Care Units Using Medical Thermography Processing and Artificial Neural Network(Elsevier, 2019) Savaşcı, D.; Ornek, A.H.; Ervural, S.; Ceylan, M.; Konak, M.; Soylu, H.Tracking temperature changes of neonatals in the neonatal intensive care unit is quite important in the prediagnosis of diseases or the evaluation of follow-up treatment. The purpose of this study is to develop an analysis system based on thermal imaging, which is the contact-free, nonionized and noninvasive method for the neonatal. For this purpose, 190 images taken from 19 healthy and 19 unhealthy neonates were used. In general, this study consists of three steps. First, the temperature map of the images was segmented. Then, discrete wavelet transform (DWT), curvelet transform and contourlet transform as multiresolution methods were applied to them, and feature vectors were extracted by using their approximation coefficients. After that, all feature vectors were given as an input to the artificial neural networks (ANN) and support vector machines. According to the obtained results, the best accuracy rate was 98.42% when using DWT+ANN. © 2019 Elsevier Inc. All rights reserved.Article Transient Heat Transfer in Pipes With Time Periodically Changing Boundary Condition(Turk Isı Bilimi ve Teknigi Dernegi, 2018) Altun, A.H.; Ateş, A.; Atmaca, Şükrü Ulaş; Koçak, Sedat; Bilir, Şefik; Atmaca, UlasTransient heat transfer in thermal entrance region of pipes with time periodically changing surface temperature is investigated. The problem is handled in a two-regional pipe for laminar, hydrodynamically developed flow by involving fluid axial conduction. The solution is made numerically by a finite-difference method. A parametric study is done to analyse the effects of Peclet number and angular frequency on heat transfer characteristics. The results show that, considerable amount of heat is diffused back towards the upstream region by axial fluid conduction, which causes preheating the fluid prior to the heated downstream region. The heat transfer characteristics, in all axial positions, including the preheated upstream and the fully developed region, are seen to change periodically in time, similar to the periodic change of the surface temperature in the downstream region. ©2018 TIBTD Printed in Turkey.Article Citation - WoS: 123Citation - Scopus: 144Point Cloud Filtering on Uav Based Point Cloud(ELSEVIER SCI LTD, 2019-02-01) Zeybek, Mustafa; Şanlıoğlu, İsmailNowadays, Unmanned Aerial Vehicles (UAVs) have been attracted wide attentions such as a new measurement equipment and mapping, which are capable of the high-resolution point cloud data collection. In addition, a massive point cloud data has brought about the data filtering and irregular data organization for the generation of digital terrain models. Filtering of point clouds contains vegetations and artificial objects play a crucial role for bare earth terrain modelling. Topographical maps rely on the data structures which are built on bare ground terrain points. The bare earth surface extraction is not the only crucial to the topographical maps but also decision-making processes such as natural hazards management, deformation analysis and interpretation. In order to filter a UAV-based 3D raw point cloud data, in this paper, filtering performance of four different algorithms using open source and commercial software's have been investigated, (1) curvature based (Multiscale Curvature Classification-MCC), (2) surface-based filtering (FUSION), (3) progressive TIN based (LasTool-LasGround module-commercial) and (4) physical simulation processing (Cloth Simulation Filtering-CSF). The applied filtering results were validated with the reference data set classified by operator. Although different filtering methodologies implemented on point clouds, these methods demonstrated similar results to extract ground on distinctive terrain feature such as dense vegetated, flat surface, rough and complex landscapes. The filtering algorithms' results revealed that UAV-generated data suitable for extraction of bare earth surface feature on the different type of a terrain. Accuracy of the filtered point cloud reached the 93% true classification on flat surfaces from CSF filtering method. (C) 2018 Elsevier Ltd. All rights reserved.Article Citation - WoS: 28Citation - Scopus: 29Separation of Formic Acid From Aqueous Solutions Onto Anion Exchange Resins: Equilibrium, Kinetic, and Thermodynamic Data(AMER CHEMICAL SOC, 2019-05-29) Zeidan, Hani; Martı, Mustafa EsenWastewaters containing organic compounds such as acids, ketones, phenols, and amines can cause critical environmental problems depending on their concentration and composition. Efficient and low-cost separation of these components may also bring their reuse in industry while cleaning the aqueous streams. Formic acid (FA) is an important raw material in industry and is widely seen in wastewaters. In this study, two different anion exchangers were compared for the separation of FA from aqueous solutions. Effects of process parameters and the mechanism were discussed. Kinetic, equilibrium, and thermodynamic studies were performed, and the data were interpreted using the relevant isotherm and kinetic models. The results showed that Lewatit MP-64 was more efficient than Amberlite IRA-96 in the range of the parameters studied. The maximum adsorption capacity obtained with Lewatit MP-64 (442.75 mg/g) was significantly higher than that were previously reported in the literature for FA separation. The data were well explained by the Langmuir isotherm model. However, relatively high R-2 values were obtained with Temkin and Freundlich isotherms. Therefore, further studies are ongoing to clarify the mechanism.Article Citation - WoS: 5Citation - Scopus: 5Experimental Investigation of Retrofitted Shear Walls Reinforced With Welded Wire Mesh Fabric(TECHNO-PRESS, 2019) Yüksel, S. BahadırThe aim of the present paper is to present the cyclic behavior of strengthened reinforced concrete shear wall test specimen, which was reinforced with cold drawn welded wire mesh fabric. Two reinforced concrete shear wall specimens have been tested in the present study. The walls were tested under reversed cyclic loading with loading applied near the tip of the walls. The control wall is tested in its original state to serve as a baseline for the evaluation of the repair and strengthening techniques. The two test specimens include a control wall and a repaired wall. The control wall test specimen was designed and detailed to simulate non-ductile reinforced concrete shear walls that do not meet the modern seismic provisions. The response of the original wall was associated with the brittle failure. The control shear wall was repaired by addition of the reinforcements and the concrete and then it was reloaded. The effectiveness of the repair technique was investigated. Test results indicate that there can be a near full restoration of the walls' strength. The data from this test, augmenting other data available in the literature, will be useful in calibrating improved analytical methods as they are developed.Article Citation - WoS: 28Citation - Scopus: 25Initiated Chemical Vapor Deposition of Poly(ethylhexyl Acrylate) Films in a Large-Scale Batch Reactor(AMER CHEMICAL SOC, 2019) Yılmaz, Kurtuluş; Şakalak, Hüseyin; Gürsoy, Mehmet; Karaman, MustafaThe present study demonstrates the successful deposition of poly(ethylhexyl acrylate) thin films in a large-scale closed-batch initiated chemical vapor deposition (iCVD) system. A horizontal cylindrical stainless-steel vacuum tank, which is highly utilized in industrial vacuum applications, was used as iCVD reactor. The effects of substrate temperature, precursor ratio, and pressure on the deposition rates were studied, and the results showed that a deposition rate of 315 nm/min can be achieved in a single run at a reactor pressure of 600 mTorr. At a lower chamber pressure of 400 mTorr, deposition rate decreases, whereas film uniformity increases. By carrying out depositions at successive cycles, thicker films could be obtained, without the need for extensive monomer consumption. The yield percentage was found to be 3.5 for the films deposited in closed-batch system at 400 mTorr, which is 35-fold larger than that of the classical iCVD flow system.Article Citation - WoS: 14Citation - Scopus: 20Removal of Methylene Blue Dye From Aqueous Solution by Semi-Interpenetrating Polymer Network Hybrid Hydrogel: Optimization Through Taguchi Method(WILEY, 2019-03-19) Yılmaz, Elif; Kaya Güzel, Gülcihan; Deveci, Hüseyin; Kaya, Gulcihan GuzelIn this study, sodium humate/poly(acrylamide-co-methacrylic acid)/kaolin semi-interpenetrating polymer network hybrid hydrogel was synthesized as an effective adsorbent for the removal of methylene blue. The morphological and structural properties, and swelling behavior in distilled water and various environments of hybrid hydrogel were investigated with different analyses and tests. The equilibrium swelling percent of hybrid hydrogel reached to 37,000% in 240min. The parameters (agitation time, concentration, dose, temperature, and pH) affecting adsorption process for methylene blue were optimized using Taguchi method. The data obtained in optimum conditions were well fitted to Langmuir adsorption isotherm and maximum adsorption capacity was determined as 833. 33mg/g. In the light of the results, the utilization of hybrid hydrogel with high swelling capacity is foreseen as a favored adsorbent in several separation processes. (c) 2019 Wiley Periodicals, Inc.