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DURAK, RIDVAN/0000-0002-3935-176X; Akman, Ferdi/0000-0002-8838-1762 WOS: 000460717500014 The total atomic attenuation cross-section values in the energy region from 14.932 to 57.142 keV were determined to obtain completely experimental values of the K shell absorption edge energies for Cd, La and Ce elements. The photoelectric cross-sections in the aforementioned energy range, K shell photoelectric cross-sections at the K edge, K shell absorption jump ratios, K shell absorption jump factors and K shell oscillator strength values were obtained with the help of the total atomic attenuation cross-sections. The measurements were performed using the secondary excitation geometry including a high resolution Si(Li) detector. 59.54 keV photon energy emitted from the Am-241 annular radioactive source was used as the primary source. The K shell characteristic X-ray energies of the some selected elements between Y and Er were used as the secondary source. The obtained experimental results were checked with the theoretical and other available experimental results, and it was observed that there is a good agreement between them.

In this study, total mass attenuation coefficient (μ/ρ) values in the energy range from 60 keV to 15 MeV for some contrast agents (Iopamidol, Metrizamide, Iohexol, Ioxaglic acid, Iopromide, Ioversol and Iopentol) were determined with the WinXCOM computer program and GEANT4 computer simulation code. Linear attenuation coefficients (μ), half value layers (HVL), tenth value layers (TVL), mean free paths (mfp), effective atomic numbers (ZEff) and effective electron densities (NEff) in the aforementioned energy range were obtained with the help of the calculated total mass attenuation coefficients. Energy absorption build-up factors (EABF) and exposure build-up factors (EBF) for contrast agents were calculated using the five-parameter geometric progression (G-P) fitting method in the energy region of 0.015 MeV ≤ E ≤ 15 MeV for different penetration depths up to 40 mfp with the help of the equivalent atomic numbers (Zeqv). Kerma relative to air values were investigated in the energy region 0.001 MeV ≤ E ≤ 20 MeV. It has been observed that Ioxaglic acid is a good radiation absorber according to the other studied contrast agents. The present results may contribute to various application areas of radiation research.

The June 12, 2017 Karaburun-Lesvos (North Aegean Sea) earthquake occurred along the NW-SE trending Lesvos fault, along the southern strand of the North Anatolian Fault Zone. In the present study seismotectonic aspects of the 2017 Karaburun-Lesvos earthquake and its aftershock sequence are studied. A rupture model based on finite source analysis of the teleseismic waveforms has shown that the earthquake was associated with a failure of single asperity. About 5 days after the mainshock a temporary seismic network of 8 broadband stations (Real-time Aftershock Forecasting in Turkey, RAFT) had been deployed along the Turkish Aegean coast to enhance the existing regional seismic monitoring and the acquired data have been used to relocate the aftershocks. The temporary deployment significantly improved the aftershock detection capacity and resulted in more precise locations. Prior to the monitoring enhancement a single widespread aftershock cluster was observed; however, the relocated aftershocks, augmented by the RAFT stations, identified two distinct spatially isolated clusters. The first day of the aftershock sequence has been used for retrospective real-time aftershock forecasting up to 7 days following the mainshock. Our results indicate that with a method developed by Omi et al (2013) can be used forecasting aftershocks over a week period successfully employing incompletely detected aftershocks occurred in the first day following the mainshock. Stress tensor analysis of the 33 aftershock source mechanisms has shown local dominance of the extensional tectonics with azimuth and plunge pairs for the three principal stress axes as sigma(1), sigma(2) and sigma(3) are (255 degrees; 76 degrees), (131 degrees; 8 degrees) and (39 degrees; 11 degrees), respectively. Coulomb stress changes imparted by the mainshock onto the nodal planes of the aftershocks show that similar to 67% of the 33 aftershocks have been exposed to positive stress change at least on one of the nodal planes.

Durak, Ridvan/0000-0002-3935-176X; DURAK, RIDVAN/0000-0002-3935-176X; Akman, Ferdi/0000-0002-8838-1762 WOS: 000347578500013 The K shell absorption jump factors and jump ratios for La2O3, Ce and Gd samples have been determined using the gamma or X-ray attenuation and EDXRF methods. It is the first time that the K shell absorption jump factor and jump ratio have been discussed for present elements using two different methods. To detect K X-rays, a high resolution Si(Li) detector was used. The experimental results of K shell absorption jump factors and jump ratios were compared with the theoretically calculated ones. (C) 2014 Elsevier Ltd. All rights reserved. Ataturk University Research FundAtaturk University [2011/82] This work was done with the support of the Ataturk University Research Fund under Project no. 2011/82.