Yazar "Han, Ibrahim" seçeneğine göre listele

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    Alloying effect on K shell X-ray fluorescence cross-sections and yields in Ti-Ni based shape memory alloys
    (Elsevier Science Bv, 2018) Alim, Bunyamin; Han, Ibrahim; Demir, Lutfu
    K shell X-ray fluorescence cross-sections (sigma(K alpha), sigma(K beta) and sigma(K)), and K shell fluorescence yields (omega(K)) of Ti, Ni both in pure metals and in different alloy compositions (TixNi1-x; x = 0.3, 0.4, 0.5, 0.6, 0.7) were measured by using energy dispersive X-ray fluorescence (EDXRF) technique. The samples were excited by 22.69 keV X-rays from a 10 mCi Cd-109 radioactive point source and K X rays emitted by samples were counted by a high resolution Si(Li) solid-state detector coupled to a 4 K multichannel analyzer (MCA). The alloying effects on the X-ray fluorescence (XRF) parameters of Ti-Ni shape memory alloys (SMAs) were investigated. It is clearly observed that alloying effect causes to change in K shell XRF parameter values in Ti-Ni based SMAs for different compositions of x. Also, the present investigation makes it possible to perform reliable interpretation of experimental sigma(K alpha), sigma(K beta) and omega(K) values for Ti and Ni in SMAs and can also provide quantitative information about the changes of K shell X-ray fluorescence cross sections and fluorescence yields of these metals with alloy composition. (c) 2017 The Egyptian Society of Radiation Sciences and Applications. Production and hosting by Elsevier B.V.
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    Evaluation the gamma, charged particle and fast neutron shielding performances of some important AISI-coded stainless steels: Part II
    (Pergamon-Elsevier Science Ltd, 2020) Alim, Bunyamin; Sakar, Erdem; Han, Ibrahim; Sayyed, M., I
    This is the second part of a two-part study on the investigation of radiation shielding performances of some important AISI-coded stainless steels (AISI-302, 304, 321 and 430). Part 1 addressed experimental evaluation by means of measured photon-material interaction parameters. In this second part, we focused on the calculation and discussion of other interaction parameters, which are a guide to choice optimum shielding materials in the nuclear processes for the present AISI-coded stainless steels. The present stainless steels have superior mechanical properties, high temperature and corrosion resistances and these properties can make them favorite materials for nuclear applications. For this reason, firstly, the incoherent scattering/total attenuation ratio (R-inc/total) and equivalent atomic number (Z(eq)) were calculated in the energy region of 0.015-15 MeV. Secondly, the exposure build-up factor (EBF) and energy absorption build-up factor (EABF) were determined to select steels by using Geometric Progression (G-P) fitting method, which have five parameters (a, b, c, d and X-k coefficients), up to penetration depth of 40 MFP at energy 0.015-15 MeV. Thirdly, the mass stopping powers (MSPs; dE/rho dx ; MeVcm(2)/g) and ranges (R-e, R-p and R alpha; mu m) for electron, proton and alpha particle interactions were calculated at energy 10 keV-20 MeV. Finally, the fast neutron removal cross-sections (FNRCSs; Sigma R; cm(-1)) were calculated. To be able to make comparison and a satisfying assessment about radiation shielding capabilities of present AISI-coded steels, all parameters were also computed for ordinary (OC), steel-scrap (SS) and steel-magnetite (SM) concretes (Fe-based steel concretes) that are most commonly used as a shielding material in many nuclear applications. The shielding capabilities of the present stainless steels against both gamma and the fast neutron and charged particle radiation were evaluated in the light of the calculated parameters. As a result of the mutual evaluation of the results obtained for the shielding concretes and the examined stainless steels, it was found that present stainless steels had excellent shielding properties compared to shielding concretes in terms of both photon radiation and particle radiation.
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    Experimental investigation of radiation shielding performances of some important AISI-coded stainless steels: Part I
    (Pergamon-Elsevier Science Ltd, 2020) Alim, Bunyamin; Sakar, Erdem; Baltakesmez, Ali; Han, Ibrahim; Sayyed, M., I; Demir, Lutfu
    The investigation of radiation shielding performances of AISI-302, 304, 321 and 430 stainless steels which have wide range of application because of their superior mechanical properties, temperature and corrosion resistances was aimed in this study. In accordance with this purpose, photon-shielding parameters of these stainless steels were calculated both experimentally and theoretically. These parameters calculated are linear attenuation coefficient, mass attenuation coefficient, mean free path, half-value layer, quarter-value layer, tenth-value layer, total atomic cross-section, total electronic cross-section, effective atomic number, effective electron number and effective conductivity. They were experimentally measured at twenty-three different energies in the range 22 keV and 1333 keV. The photon energies were obtained from seven different radioactive sources (Na-22,Co- 60, Am-24(1) (109)cd , (137)cs, Eu-152 and Ba-133) . The Si(Li) and NaI(Tl) detectors were separately used taking into account of energy-efficient regions to counting process at narrow-beam transmission geometry. In addition, all these parameters were computed at the 15 keV-15 MeV wide energy range, theoretically. In order to make a satisfying assessment about radiation shielding capabilities of AISI 302, 304, 321 and 430 alloys, all calculations were also made for ordinary, steel-scrap and steel-magnetite concretes (Fe-based steel concretes) that are most commonly used as shielding material in many nuclear applications. According to the results obtained, it was observed that the radiation shielding performances of AISI 300 austenitic stainless steel series with containing Ni are superior to that of both AISI 430 ferritic stainless steel and examined concretes.
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    Investigation of alloying effects on XRF parameters of 3d transition metals in Permendur49, Kovar and Ti50Co50 alloys
    (Taylor & Francis Ltd, 2018) Alim, Bunyamin; Ugurlu, Mine; Han, Ibrahim; Demir, Lutfu
    The alloying effects on X-ray fluorescence (XRF) parameters such as K shell fluorescence cross-sections (sigma(K alpha), sigma(K beta) and sigma(K)), K shell average fluorescence yields (omega(K)) and K to L shell vacancy transfer probabilities (eta(KL)) of V, Ti, Fe, Co and Ni 3d transition metals in Permendur49 (Fe49Co49V2), Kovar (Fe54Ni29Co17) and Ti50Co50 alloys have been carried out by X-ray fluorescence studies. K X-ray intensity ratios of these 3d transition metals in both pure form and present alloys have been measured following excitation by 22.69 keV X-rays from a 10 mCi Cd-109 radioactive point source. The characteristic K-X-ray spectra from samples were detected by a high-resolution Si(Li) solid-state detector. The investigated fluorescence parameters of present 3d transition elements in alloys indicate significant differences with respect to the pure metals. Consequently, the observed change of the investigated fluorescence parameters can be attributed to the delocalization and charge transfer phenomena between the 3d elements in alloys. (c) 2017 The Egyptian Society of Radiation Sciences and Applications. Production and hosting by Elsevier B.V.
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    Precipitation-hardening stainless steels: Potential use radiation shielding materials
    (Pergamon-Elsevier Science Ltd, 2022) Alim, Bunyamin; Ozpolat, Ozgur Firat; Sakar, Erdem; Han, Ibrahim; Arslan, Ibrahim; Singh, V. P.; Demir, Lutfu
    In this study, it was focused on the research of new materials with high attenuation efficiency that can be used as radiation shielding material due to the incapability of conventional materials. In accordance with this purpose, the radiation shielding capabilities of four different precipitation-hardening stainless steels (PH-SSs), which are symbolized 15-5PH, 15-7PH, 17-4PH and 17-7PH, were determined both experimentally and theoretically in a wide range of radiation energy. For experimental measurements, two different detectors (Si(Li) and Na(Tl)) and twenty-three different photon energies (from 22.1 to 1332.5 keV) emitted from seven different radionuclides were used in narrow-beam transmission geometry. Phy-X/PSD software were used for theoretical calculations. The theoretically calculated parameters were determined both in the photon energies emitted by the radionuclides used in the experiment and in the continuous energy range of 0.015-15 MeV. Furthermore, in order to make a remarkable assessment of the integration of PH-SSs to nuclear energy applications, the all results obtained have been compared with the corresponding values of Fe-based steel concretes (steel-scrap (SS) and steel magnetite (SM)), which are widely used as conventional shield materials in nuclear power plants. Moreover, in order to choose the best material to be used in nuclear applications among the PH-SSs, the results were evaluated comparatively in terms of both the characteristics of the materials and the magnitude of the radiation shielding parameters. Consequently, it was concluded that the material with the best radiation shielding performance among the examined PH-SSs was 15-7PH and the radiation shielding performance ranking was generally in the form of 15-7PH >= 15-5PH > 17-4PH > 17-7PH > SM > SS. Due to both high attenuation efficiency and superior properties for radiation shielding, it was determined that the PH-SSs can be used as new shielding materials in nuclear applications.