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Öğe Alloying effect on K shell X-ray fluorescence parameters and radiative Auger ratios of Co and Zn in ZnxCo1-x alloys(Elsevier Science Bv, 2010) Aylikci, N. Kup; Tirasoglu, E.; Karahan, I. H.; Aylikci, V.; Cengiz, E.; Apaydin, G.In this study, sigma K-alpha,K-beta production cross-sections, omega(K) fluorescence yields, K-beta/K-alpha, KLM/K-alpha and KMM/K-beta intensity ratios of Co and Zn in different alloy compositions were measured. The alloying effects on the fluorescence parameters of Co and Zn were investigated. The changes in these parameters were interpreted according to the rearrangement of valance state electrons and the charge transfer process between the 3d elements which constitute the alloys. The samples were excited by 59.5 keV gamma-rays from a Am-241 annular radioactive source. K X-rays emitted by samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. (C) 2009 Elsevier B.V. All rights reserved.Öğe Alloying effect on K X-ray intensity ratios, K X-ray production cross-sections and radiative Auger ratios in superalloys constitute from Al, Ni and Mo elements(Elsevier Science Bv, 2010) Aylikci, N. Kup; Tirasoglu, E.; Karahan, I. H.; Aylikci, V.; Eskil, M.; Cengiz, E.In this study, sigma(K alpha,beta) production cross-sections, K-beta/K-alpha, KLM/K-alpha and KMM/K-beta RAE intensity ratios of Ni and sigma(K alpha), sigma(K beta 1,2) production cross-sections, K-beta 1,K-3/K-alpha, K-beta 2,K-4/K-alpha, K-beta 2,K-4/K-beta 1,K-3, KLM/K-alpha and KMM/K-beta RAE intensity ratios of Mo have been measured in pure metals and in superalloy specimens. The samples were excited by 59.5 keV gamma-rays from a Am-241 annular radioactive source. K X-rays emitted by samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. The effect of alloying on the fluorescence parameters of Ni and Mo, phase structure, and corrosion behavior were investigated. The X-ray fluorescence parameters of Ni and Mo in superalloys indicate significant differences with respect to the pure metals. These differences are attributed to the reorganization of valence shell electrons and/or charge transfer phenomena in superalloys. (C) 2010 Elsevier B.V. All rights reserved.Öğe Alloying effect on K-shell fluorescence parameters of porous NiTi shape memory alloys(Elsevier Science Bv, 2014) Cengiz, E.; Ozkendir, O. M.; Kaya, M.; Tirasoglu, E.; Karahan, I. H.; Kimura, S.; Hajiri, T.The K-alpha,K-beta shell production cross-sections and K-beta/K-alpha intensity ratios of porous Ni -49 at% Ti shape memory alloys were determined using energy dispersive X-ray fluorescence (EDXRF) technique. Also, the alloying effect on the K shell fluorescence parameters was investigated. The samples were excited by 59.5 key gamma-rays from an Am-241 annular radioactive source. The K X-rays emitted by the samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 key. The structure analyses of the samples were also made using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The deviations between the present results and theoretical values, calculated for pure Ti and Ni, were attributed to charge transfer phenomena and/or rearrangement of valance shell electrons and porosity. (C) 2014 Elsevier B.V. All rights reserved.Öğe Assessment of the mass attenuation parameters with using gamma-rays for manganese substituted nano hydroxyapatite(Pergamon-Elsevier Science Ltd, 2019) Koksal, O. K.; Apaydin, G.; Tozar, A.; Karahan, I. H.; Cengiz, E.Manganese substituted hydroxyapatite nanoparticles (nMnHAp) were produced using the ultrasonic wet chemical method. The elemental analysis was performed using Scanning Electron Microscopy (SEM) with integrated Energy Dispersive X-ray Spectrometry (EDX). The mass attenuation coefficients of manganese substituted hydroxyapatite nanoparticles have been measured at 59.5 keV gamma energy emitted from Am-241 radioisotope annular source with 50 mCi activity by using Ultra Low Energy Germanium Detector. These values are found to be in good agreement with theoretical values based on calculated XCOM data. Electron densities and effective atomic numbers were calculated by using the mass attenuation coefficients. Also, the mass attenuation coefficient of the real bone was determined as experimentally. The obtained results may provide information on how much radiation is transmitted through the sample when they are exposed to gamma-rays at 59.5 keV by comparing real bone.Öğe Chemical Analysis of Hydroxyapatite Artificial Bone Powders by Energy Dispersive X-Ray Fluorescence Spectrometry (EDXRF)(Office Spectroscopy & Spectral Analysis, 2018) Koksal, O. K.; Apaydin, G.; Cengiz, E.; Samek, L.; Karahan, I. H.; Tozar, A.; Lankosz, M.Stoichiometric hydroxyapatite (HA) nanoparticles were synthesized by a wet chemical method. Calcium nitrate tetra hydrate used as calcium source and dibasic ammonium phosphate used as phosphorous source. Calcium nitrate tetra hydrate and dibasic ammonium phosphate solutions were prepared by dissolving the salts in distilled water. Stoichiometric hydroxyapatite nanoparticles used by artificial bone powders and synthesized by a wet chemical method were analyzed using EDXRF method. The concentrations of K, Ca, Ti, V, Cr, Fe, Ni, Cu, Sr and Pb for artificial bone powders have been determined. Besides, Calcium contents were evaluated according to the agitation time and temperature in the production process.Öğe Effect of pH treatment on K-shell x-ray intensity ratios and K-shell x-ray-production cross sections in ZnCo alloys(Amer Physical Soc, 2011) Aylikci, N. Kup; Aylikci, V.; Kahoul, A.; Tirasoglu, E.; Karahan, I. H.; Cengiz, E.In this study, empirical and semiempirical K-shell fluorescence yields (omega(K)) and K beta/K alpha intensity ratios from the available experimental data for elements with 23 <= Z <= 30 were calculated to compare them with elements in different alloys. The experimental data are fitted using the quantity [omega(K)/(1 -omega(K))](1/4) vs Z to deduce the empirical K-shell fluorescence yields and K beta/K alpha intensity ratios. The empirical and semiempirical K-shell fluorescence yield values were used to calculate the K x-ray-production cross-section values for pure Co and Zn elements. Also, sigma(K alpha), sigma(K beta) production cross sections and K beta/K alpha intensity ratios of Co and Zn have been measured in pure metals and in different alloy compositions which have different pH values. The samples were excited by 59.5-keV. rays from a Am-241 annular radioactive source. K x rays emitted by samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. The effect of pH values on alloy compositions and the effect of alloying on the fluorescence parameters of Co and Zn were investigated. The x-ray fluorescence parameters of Co and Zn in the alloying system indicate significant differences with respect to the pure metals. These differences are attributed to the reorganization of valence shell electrons and/or charge transfer phenomena.Öğe Elemental analysis for iron, cobalt, copper and zinc decorated hydroxyapatite synthetic bone dusts by EDXRF and SEM(Elsevier Science Bv, 2019) Koksal, O. K.; Wrobel, P.; Apaydin, G.; Cengiz, E.; Lankosz, M.; Tozar, A.; Karahan, I. H.Iron, cobalt, copper and zinc decorated hydroxyapatite nanoparticles were produced with using ultrasonically assisted wet chemical method. Calcium nitrate tetra hydrate and dibasic ammonium phosphate were used as calcium and phosphorous source, respectively. Calcium nitrate tetra hydrate and dibasic ammonium phosphate solutions were prepared by dissolving the salts in distilled water and at different concentrations of decorated elements (iron, cobalt, copper and zinc) were appended to the calcium nitrate tetra hydrate solution. Stoichiometric decorated hydroxyapatite nanoparticles were analysed by energy dispersive X-ray fluorescence (EDXRF) with using standard method and the element analysis was determined with looking at the grain structures by Energy Dispersive X-Ray (EDX) and scanning electron microscopy (SEM). Not only have the concentrations of decorated metals but also calcium and phosphorus ratio for artificial bone powders been determined. As a result, calcium and phosphor ratio and metal decorated contents were evaluated according to the production values and compared previous studies. The answer to the question of how much of the contribution amounts was searched.Öğe L shell X-ray fluorescence parameters of Pb in phthalocyanine complexes(Pergamon-Elsevier Science Ltd, 2015) Dogan, M.; Cengiz, E.; Nas, A.; Tirasoglu, E.; Kantekin, H.; Aylikci, V.The L shell X-ray intensity ratios L-i/L-alpha (i=l, beta and gamma), the production cross-sections sigma(Li) (i=l, alpha, beta and gamma) and the L-3 subshell fluorescence yields omega(L3) have been investigated for the element Pb in the phthalocyanine complexes. The measurements have been performed using an Am-241 annular radioactive source and an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. The experimental values have been compared with the theoretical values of pure Pb element. (C) 2015 Elsevier Ltd. All rights reserved.Öğe Traces of Defects in the Electronic Structure of Porous Ni-Ti Alloys(Journal Mater Sci Technol, 2013) Ozkendir, O. M.; Cengiz, E.; Tirasoglu, E.; Kaya, Mehmet; Karahan, I. H.; Orhan, N.The electronic structures of Ni-Ti shape-memory alloy samples were investigated by X-ray absorption fine structure (XAFS) spectroscopy both experimentally and theoretically. In the experimental section, the samples were measured at low temperature to determine the persistent traces of both preheating process and atomic concentration effects on the crystal and electronic structure by X-ray absorption near-edge structure (XANES) spectroscopy. As a second step, the extended-X-ray absorption fine structure (EXAFS) calculations, which are based on different choices of one electron potentials according to Ti coordinations by using the real space multiple scattering method FEFF 8.2 code, were performed. The crystallographic and electronic structures of the porous Ni-Ti alloys were tested at various temperatures ranging from 5 to 1323 K.
