In this work, the specific activities of natural radionuclides, namely <sup>238</sup>U series, <sup>232</sup>Th series and <sup>40</sup>K, have been measured in collected sedimentar...In this work, the specific activities of natural radionuclides, namely <sup>238</sup>U series, <sup>232</sup>Th series and <sup>40</sup>K, have been measured in collected sedimentary phosphate deposits samples from El-Hamraween, El-Quser and Safaga phosphate mines in Egypt. HPGe γ-spectrometry was used. This study was undertaken to estimate the radiation hazard indices in phosphate mining at the studied mines on their occupational workers, to establish correlation relationships between the some measured heavy metals such as As, Cd and Pb in blood workers and their concentration in phosphate rock ores and to determinate the biomarkers in the blood workers such as malondialdehyde (MDA) and superoxide dismutase (SOD). The phosphate mine sample of El-Hamrawein has the lowest activity concentration of <sup>226</sup>Ra, <sup>232</sup>Th and <sup>40</sup>K in comparison to the phosphate mine samples of El-Quseir and Safaga (El-Hamrawein kg<sup>-</sup>1</sup><sup></sup>, 122.4 to 188.3 Bq·kg<sup>-</sup>1</sup></sup> and 115.4 to 165.8 Bq·kg<sup>-</sup>1</sup></sup> for Safaga, El-Quseir and El-Hamrawein, respectively. For <sup>232</sup>Th activity concentrations varied from 135.6 to 212.3 Bq·kg<sup>-</sup>1</sup></sup>, 112.8 to 167.4 Bq·kg<sup>-</sup>1</sup></sup> and 132.8 to 188.6 Bq·kg<sup>-</sup>1</sup></sup> for Safaga, El-Quseir and El-Hamrawein, respectively. For <sup>40</sup>K activity concentrations varied from 225.2 to 312.8 Bq·kg<sup>-</sup>1</sup>, 168.7 to 268.9 Bq·kg<sup>-</sup>1</sup></sup> and 95.2 to 155.8 Bq·kg<sup>-</sup>1</sup></sup> for Safaga, El-Quseir and El-Hamrawein, respectively. The workers of old ages have higher concentration of the investigated heavy metals than those of young ages. There is a good relation between the concentration of the investigated metals in phosphate mine samples and their concentration in blood of the occupational workers in these mines.展开更多
In this work, the Styrene-butadiene rubber (SBR)/lead oxide and the Styrene-butadiene rubber (SBR)/lead nitrate composites were prepared as gamma-radiation shielding materials. The investigated materials were prepared...In this work, the Styrene-butadiene rubber (SBR)/lead oxide and the Styrene-butadiene rubber (SBR)/lead nitrate composites were prepared as gamma-radiation shielding materials. The investigated materials were prepared with three different weight percentage of lead oxide and lead nitrate (30, 50 and 70 wt%). The mass attenuation coefficients (μ<sub>m</sub>) for all composite samples were measured experimentally at 511 and 661.6 keV photon energies. The measurements were made by performing transmission experiments with a 3'' × 3'' NaI (Tl) scintillation detector, which had an energy resolution of 7% at 0.662 MeV for the gamma-rays from the decay of <sup>137</sup>Cs. The effective atomic numbers (Z<sub>eff</sub>) and the effective electron densities (N<sub>eff</sub>) were determined experimentally. Also they were determined theoretically using the obtained μ<sub>m</sub> values for the studied composites samples by WinXCom program. The obtained results show that the experimental values of the composites are found to be in a good agreement with the theoretical values. It is recognized that the mass attenuation coefficient (μ<sub>m</sub>), effective atomic numbers (Z<sub>eff</sub>) and the effective electron densities (N<sub>eff</sub>) are increased in the composite samples which contain lead oxides than which contain lead nitrates. Finally, the Styrene-butadiene rubber (SBR)/lead oxide is better than Styrene-butadiene rubber (SBR)/lead nitrate polymer as gamma radiation shielding.展开更多
文摘In this work, the specific activities of natural radionuclides, namely <sup>238</sup>U series, <sup>232</sup>Th series and <sup>40</sup>K, have been measured in collected sedimentary phosphate deposits samples from El-Hamraween, El-Quser and Safaga phosphate mines in Egypt. HPGe γ-spectrometry was used. This study was undertaken to estimate the radiation hazard indices in phosphate mining at the studied mines on their occupational workers, to establish correlation relationships between the some measured heavy metals such as As, Cd and Pb in blood workers and their concentration in phosphate rock ores and to determinate the biomarkers in the blood workers such as malondialdehyde (MDA) and superoxide dismutase (SOD). The phosphate mine sample of El-Hamrawein has the lowest activity concentration of <sup>226</sup>Ra, <sup>232</sup>Th and <sup>40</sup>K in comparison to the phosphate mine samples of El-Quseir and Safaga (El-Hamrawein kg<sup>-</sup>1</sup><sup></sup>, 122.4 to 188.3 Bq·kg<sup>-</sup>1</sup></sup> and 115.4 to 165.8 Bq·kg<sup>-</sup>1</sup></sup> for Safaga, El-Quseir and El-Hamrawein, respectively. For <sup>232</sup>Th activity concentrations varied from 135.6 to 212.3 Bq·kg<sup>-</sup>1</sup></sup>, 112.8 to 167.4 Bq·kg<sup>-</sup>1</sup></sup> and 132.8 to 188.6 Bq·kg<sup>-</sup>1</sup></sup> for Safaga, El-Quseir and El-Hamrawein, respectively. For <sup>40</sup>K activity concentrations varied from 225.2 to 312.8 Bq·kg<sup>-</sup>1</sup>, 168.7 to 268.9 Bq·kg<sup>-</sup>1</sup></sup> and 95.2 to 155.8 Bq·kg<sup>-</sup>1</sup></sup> for Safaga, El-Quseir and El-Hamrawein, respectively. The workers of old ages have higher concentration of the investigated heavy metals than those of young ages. There is a good relation between the concentration of the investigated metals in phosphate mine samples and their concentration in blood of the occupational workers in these mines.
文摘In this work, the Styrene-butadiene rubber (SBR)/lead oxide and the Styrene-butadiene rubber (SBR)/lead nitrate composites were prepared as gamma-radiation shielding materials. The investigated materials were prepared with three different weight percentage of lead oxide and lead nitrate (30, 50 and 70 wt%). The mass attenuation coefficients (μ<sub>m</sub>) for all composite samples were measured experimentally at 511 and 661.6 keV photon energies. The measurements were made by performing transmission experiments with a 3'' × 3'' NaI (Tl) scintillation detector, which had an energy resolution of 7% at 0.662 MeV for the gamma-rays from the decay of <sup>137</sup>Cs. The effective atomic numbers (Z<sub>eff</sub>) and the effective electron densities (N<sub>eff</sub>) were determined experimentally. Also they were determined theoretically using the obtained μ<sub>m</sub> values for the studied composites samples by WinXCom program. The obtained results show that the experimental values of the composites are found to be in a good agreement with the theoretical values. It is recognized that the mass attenuation coefficient (μ<sub>m</sub>), effective atomic numbers (Z<sub>eff</sub>) and the effective electron densities (N<sub>eff</sub>) are increased in the composite samples which contain lead oxides than which contain lead nitrates. Finally, the Styrene-butadiene rubber (SBR)/lead oxide is better than Styrene-butadiene rubber (SBR)/lead nitrate polymer as gamma radiation shielding.
