Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Deposition of (La,Sr)CoO₃-δ and (La,Sr)₂CoO₄-δ Cathode Layers on Gadolinia-Doped Ceria by Electrospray Deposition(Springer, 2025) Ergen, Emre; Akkurt, SedatLa-, Sr-, and Co-based oxides have proven their performances in the cathode layers of intermediate temperature levels of solid oxide fuel cells (SOFC), and hence have been frequently studied. They are deposited on the electrolyte layer by chemical vapor deposition (CVD), screen printing, pulsed laser deposition (PLD), etc. The electrospray deposition (ESD) proved itself as an effective and facile method for cathode deposition. Cathode layers deposited on gadolinia-doped ceria (GDC) with the compositions of (La0.5Sr0.5)CoO3, (La0.8Sr0.2)CoO3, (La0.5Sr0.5)2CoO4, and (La0.8Sr0.2)2CoO4 are known to provide low resistance values which are critical in cell performance. In this study, ESD is used for the first time as the coating method of these compositions. Area-specific resistance (ASR) measurements made by electrochemical impedance spectroscopy (EIS) showed promising results. Particularly, the sample coated in (La0.5Sr0.5)CoO3 composition showed an ASR value of 0.11 Omega.cm2 at 700 degrees C. ESD showed the ability to control the cathode coating microstructure by controlling the spraying parameters.Article Citation - WoS: 1Citation - Scopus: 1ANN model predicts floor tile properties(American Ceramic Society, 2004) Akkurt, Sedat; Özcan, Selçuk[No abstract available]Article Citation - WoS: 15Citation - Scopus: 16Fabrication of Lscf and Lscf-Gdc Nanocomposite Thin Films Using Polymeric Precursors(Springer, 2020) Sındıraç, Can; Ahsen, Ali; Öztürk, Osman; Akkurt, Sedat; Birss, Viola, I; Büyükaksoy, AligülLa1-xSrxCoyFe1-yO3 (LSCF) and LSCF-gadolinia-doped ceria (LSCF-GDC) composites are used as solid oxide fuel cell (SOFC) cathodes. In the present study, to maximize the LSCF/gas and LSCF/GDC interfacial area and thus enhance the performance, we fabricated both single-phase LSCF and composite LSCF-GDC thin-film electrodes using a facile and cost-effective polymeric precursor technique. This method involves molecular level mixing of cations in solution form and results in average particle sizes of ca. 72 nm and 60 nm upon annealing at 700 degrees C, respectively. For LSCF, electrochemical impedance spectroscopy measurements indicate very low electrode polarization resistances of ca. 0.6 omega cm(2) per electrode at 600 degrees C. However, the addition of GDC results in poorer electrochemical activity but better microstructural and electrochemical stability, all at 600 degrees C. Surface analysis revealed that Fe surface segregation occurs in the single-phase LSCF, while predominantly Co segregation is observed at the LSCF-GDC composite electrode surface.Article Citation - WoS: 4Citation - Scopus: 4Effects of Catalyst Precursor Type and Preparation Conditions, and Solvent Type on Activity and Selectivity of Pt/Sio2 Catalyst in Citral Hydrogenation(Walter de Gruyter GmbH, 2011) Depboylu, Can Okan; Yılmaz, Selahattin; Akkurt, SedatIn this study, citral hydrogenation reaction in liquid phase over silica gel supported Pt catalysts was investigated. It was desired to hydrogenate carbonyl group selectively to produce valuable unsaturated alcohols, namely geraniol and nerol. Pt/SiO2 catalysts were prepared by impregnation method. The effects of parameters investigated in the present study included Pt precursor type (hexachloroplatinic acid (HCLPA), platinum II acetylacetonate (PAA)), catalyst activation temperature (350°C and 450°C), catalyst activation without calcination, catalyst washing with 0.1 M NaOH and solvent type (ethanol, 2-pentanol). The catalysts activities and selectivities were affected by the type of precursor and activation temperature. The maximum citral conversion (89.50 percent) was achieved at lower activation temperature (350°C) with PAA precursor based catalyst. It was observed that higher activation temperature provided lower citral conversion but higher selectivity to unsaturated alcohols; increasing the activation temperature to 450°C decreased citral conversion to 26.10 percent. But selectivity to unsaturated alcohols, geraniol and nerol, increased from 7.06 to 54.60 percent. Catalyst washing and 2-pentanol prevented acetal formation. Catalyst activation without calcination gave lower citral conversion (20.84 percent) and selectivity to unsaturated alcohols (30.00 percent). Copyright © 2011 The Berkeley Electronic Press. All rights reserved.Article Doe and Ann Models for Powder Mixture Packing(American Ceramic Society, 2007) Akkurt, Sedat; Romagnoli, Marcello; Sütçü, MücahitDesign of experiments (DOE) and artificial neural network (ANN) techniques were used to study packing of fused alumina powders composed of three different sizes of particles. The first is the mixture design technique that produces a polynomial model of the powder-packing system. While, the ANN technique is extensively used to model complex systems in many fields. The methodological approach used is mixture design, which can be used to study the influences of two or more additives. It is a structured and organized method for determining the relationship between the components and the output of that process. The mixture design approach permits optimization of size distribution to obtain a target value of porosity. Sensitivity analysis involves the use of the developed ANN model to predict outputs (porosity) at varying levels of the input factor effects.Article Citation - WoS: 121Citation - Scopus: 136Quantification of Caco3-Caso3·0.5h 2o-Caso4·2h2o Mixtures by Ftir Analysis and Its Ann Model(Elsevier Ltd., 2004) Böke, Hasan; Akkurt, Sedat; Özdemir, Serhan; Göktürk, E. Hale; Caner Saltık, Emine N.A new quantitative analysis method for mixtures of calcium carbonate (CaCO3), calcium sulphite hemihydrate (CaSO 3·1/2H2O) and gypsum (CaSO 4·2H2O) by FTIR spectroscopy is developed. The method involves the FTIR analysis of powder mixtures of several compositions on KBr disc specimens. Intensities of the resulting absorbance peaks for CaCO 3, CaSO3·1/2H2O and CaSO 4·2H2O at 1453, 980, 1146 cm-1 were used as input data for an artificial neural network (ANN) model, the output being the weight percent compositions of the mixtures. The training and testing data were randomly separated from the complete original data set. Testing of the model was done with successfully low-average error levels. The utility of the model is in the potential ability to use FTIR spectrum to predict the proportions of the three substances in unknown mixtures.Article Citation - WoS: 11Citation - Scopus: 19Corrosion of Mgo-C Ladle Refractories(American Ceramic Society, 2003) Akkurt, Sedat; Leigh, Herbert DavidThe corrosion behavior of magnesia-carbon (MgO-C) refractories used in slag lines of secondary steelmaking vessels was investigated using a slag test at high temperature under a protective atmosphere of argon or argon and carbon monoxide. For the investigation, a test method was developed and a statistically designed set of experiments was used to develop a polynomial model of corrosion. The model predicted the increased corrosion as time, temperature and oxygen partial pressure in the atmosphere increased and as slag basicity decreased. The degree of slag attack was found to be dependent on the rate of carbon loss.