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61.
In this study, the practical methodologies are described for the determination of the factors for the self-absorption effect (Fs), spectral interferences (Fcsi), and true coincidence summing effects (Fcoi), which are used in direct gamma-spectrometric measurement of radionuclides such as 210Pb, 238U, 234Th, 226Ra, 214Pb, 228Ac, 208Tl, 214Bi, 137Cs and 40K in samples. To validate the applied methods, certified reference materials (CRMs) of lake and stream sediments were measured with an n-type Germanium (Ge) detector-calibrated using a multinuclide reference source. The highest self-absorption correction factors ranged from Fs = 1.44–2.10 for 46.5 keV peak (210Pb) and Fs = 1.25–1.60 for 63.3 keV peak (234Th) lying in the low energy region of the spectrum. The systematic influence was observed for 186.2 keV (226Ra) peak due to spectral interferences with the 235U contribution. For this peak, Fcsi is changed from 0.921 to 0.955. Additionally, the present study suggests that true coincidence summing (TCS) effects are not dominant, except for 208Tl and 214Bi for which Fcoi ranged from 1.179 to 1.192 an ranged from 1.140 to 1.151, respectively. 相似文献
62.
Toxic effects of five commonly used pesticides on the biomass of a municipal activated sludge system were determined on the basis of the reduction in the oxygen uptake rate (OUR) and specific oxygen uptake rate (SOUR). Toxicity levels of the selected pesticides were determined by employing a modified OECD 209 (Organisation for Economic Cooperation and Development) method which was performed as batch experiments using a respirometer. Copper sulphate (CuSO4 · 5 H2O), copper oxychloride (Cu2Cl(OH)3), copper calcium oxychloride (CaCu3Cl2(OH)6) as copper‐based pesticides and chlorsulphuron (C12H12ClN5O4S), 2,4‐dichlorophenoxyacetic acid (2,4‐D) (C8H6Cl2O3) as synthetic organic pesticides were selected for the experiments. The EC50 values were determined to be 78, 249 and 281 mg/L for CuSO4 · 5 H2O, Cu2Cl(OH)3 and CaCu3Cl2(OH)6, respectively. Corresponding values for C12H12ClN5O4S and 2,4‐D were 860 and 3664 mg/L, respectively. Results indicated that toxicity effects of copper‐based pesticides were higher than that of synthetic organic pesticides. CuSO4 · 5 H2O was found to exert the highest toxicity among the copper‐based pesticides, whereas, C12H12ClN5O4S was determined to be the most toxic among the organic pesticides on activated sludge biomass. 相似文献
63.
The North Anatolian Fault crosses the Sea of Marmara from east to west. Tectonic features of the Sea of Marmara were studied
using multi-channel deep seismic reflection data. The northern branch of the North Anatolian Fault is active as a right lateral
strike-slip fault zone and indicates both negative and positive flower structures. The North Anatolian Fault splays into two
faults at the Sea of Marmara as a northern branch and north segment of the southern branch. The northern branch named the
Main Marmara Fault extends in a complicated manner from the north of the Kapıdağı Peninsula to westward in the Sea of Marmara.
The north segment of southern branch extends between the Gemlik and Bandırma gulfs in the south of the Sea of Marmara. In
addition, uplift areas arose by compression and a push-up style in between the Kapıdağı Peninsula and the Main Marmara Fault.
The North Anatolian Fault is characterized by a negative flower structure in basins and push-up style in uplift areas in the
Sea of Marmara. An uplift area arose between the north segment of the southern branch and the northern branch of the North
Anatolian Fault. The north segment of the southern branch of the North Anatolian Fault is a strike-slip fault and displays
a pull-apart style in the seismic reflection data. 相似文献