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    First-principles study of elastic and vibrational properties of Ni2MnIn magnetic shape memory alloys
    (Springer, 2011) Agduk, S.; Gokoglu, G.
    We present the results of ab initio calculations of lattice dynamics and the second order elastic stiffness constants of nickel-based magnetic shape memory alloy Ni2MnIn in stoichiometric composition. The plane wave basis sets and pseudopotential method within spin-polarized generalized gradient approximation (sigma-GGA) scheme of the density functional theory (DFT) is applied. Elastic constants are calculated by tetragonal and monoclinic isochoric strains on cubic L2(1) structure. The calculated elastic constants agree very well with the recent ultrasonic experimental data. Phonon dispersion spectra are investigated within linear response technique of the density functional perturbation theory (DFPT). A vibrational anomaly is observed in phonon spectra at the transverse acoustic mode (TA(2)) in [zeta zeta 0] direction at wavevector zeta = 0.3 as an indication of the structural instability of the system to shear deformation. This anomaly is also verified by the low shear modulus and large elastic anisotropy ratio. Phonon dispersion curves are in excellent agreement with the results of recent neutron diffraction experiments.
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    Indoor radon concentration measurements for University of Karabük building using Cr-39 detector
    (American Institute of Physics Inc., 2023) Aal-Shabeeb, K.H.M.; Erer, A.M.; Agduk, S.; Kanbur, U.; Oguz, S.; Çakmak, N.
    Radon concentration for the summer seasons of 2020 was measured in 12 buildings of Karabük University / Karabük governorate / Turkey using the passive technique. Solid state nuclear track detectors (CR-39) were used for calculating the track of alpha particles emitted from the decay of radon. The results of 222Rn concentration for ground and underground showed that the lowest value was 8.547 Bq/m3 in Literature Faculty (LF) building, and the highest value was 83.498 Bq/m3 in Foreign Language High School (LHS) building. All radon concentrations are within the acceptable concentrations for natural exposure by International Committee of Radiation Protection [ICRP, 2009]. Annual effective dose (AED), lung cancer cases per year per million person (CPPP), potential alpha energy concentration (PAEC), the dose rate for soft tissues, the dose rate for the lungs and the effective dose equivalent rate have a range of 0.216 - 2.107 mSv/y, 0.634x10-2 - 6.19x10-2 per million person, 1.04 - 10.155 mWL, 0.043 - 0.417 nGy/h, 0.342 - 3.340 nGy/h and 1.538 - 15.030 nGy/h respectively, which are all below the recommended limits by the international agencies [UNSCEAR & ICRP]. © 2023 Author(s).
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    Measurement of outdoor Radon Concentrations in Soil Samples collected from Karabuk University in Turkey by using CR-39 Detector
    (IOP Publishing Ltd, 2021) Mahdi, K.H.; Erer, A.M.; Kanbur, U.; Agduk, S.; Oguz, S.; Cakmak, N.
    In this work, radon gas concentration in (35) samples of soil collected from Karabuk University in Turkey was measured by using nuclear track detector (CR-39). The content of radium, the rate of surface exhalation and the rate of mass exhalation have been assessed. The concentrations of radon were varied from (16.348 Bq.m-3) to (196.988 Bq.m-3). Results indicate that the equivalent content of radium varied from (0.386245 Bq.kg-1) to (4.654255 Bq.kg-1). The exhalation rate for surface varied from (0.002007 Bq.m-1.h-1) to (0.023031 Bq.m-1.h-1). The exhalation rate for mass varied from (0.000319 Bq.kg-1.h-1) to (0.00366 Bq.kg-1.h-1). All the obtained results found to be less than the corresponding limits for the world. Thus, based on the radon gas concentration and radiation, the equivalent content of radium (CRa), exhalation rate for the area (EArea) and exhalation rate for the mass (EMass) in this area have no risk to the human's health. © Published under licence by IOP Publishing Ltd.