Influence of Reaction Time, Reducing Agent and Zinc Precursors on the Morphological Structures of Zinc Oxide

ZnO either nanoparticles or nanorods were synthesized via sol-gel technique. Many factors were studied and optimized in order to obtain different morphological structures of nano-ZnO. Effect of reaction time (3, 6, 12, 24 and 48 hours) has been studied to optimize the best preparation condition. Reducing agent (NH3, NaOH and KOH) is one of the factors affect on morphological structures, which has been studied in this work. Other effect has been studied in this work is zinc precursors such as Zn(NO3)2, ZnAc2, ZnCl2, and ZnBr2. The morphological structures of prepared ZnO were revealed using scanning electron microscope (SEM) and the aspect ratios were calculated. x-ray diffraction (XRD) patternsexposed a highly crystallized wurtzite structure and used for identifying phase structure and chemical state of ZnO under different preparation conditions.Keywords: sol-gel, morphological structures, reducing agent, SEM, preparation conditions

The Status of Natural Radioactivity and Heavy Metals Pollution on Marine Sediments Red Sea Coast, At Safaga, Egypt

Natural 226Ra, 232Th and 40K radio nuclides concentration in beach Sediments along Safaga coast of Red sea, Egypt has been carried out using a NaI (Tl) gamma ray spectrometric technique. The total average concentrations of radionuclides ± uncertainty of 226Ra, 232Th and 40K were 22.2 ± 1.7, 19.2 ± 2.5, and 477.6 ± 27.6 Bqkg-1, respectively. The total average absorbed dose rate is found to be 41.4 nGyh-1, whereas the annual effective dose rate has an average value of 54 μSvy-1. The total organic matter (TOC), carbonates (CaCo3) and Heavy metals distribution have been measured at some locations, the concentration for the investigated heavy metals overtake the allowable limits recommended by the Canadian Environmental Quality Guidelines, this assigned to the ratio of metals pollution is caused by anthropogenic activities (phosphate shipment as in Abu Tartour harbor and navigation as in Touristic harbor) and or by natural impacts such in mangrove interment. Statistical analyses were carried out between the parameters obtained from the radioactivity to know the existing relations and to study the spatial distribution of radionuclide

Assessment of natural radionuclides and heavy metal concentrations in marine sediments in view of tourism activities in Hurghada city, northern Red Sea, Egypt

The specific activity of 40K, 232Th and 226Ra in marine sediment samples collected from National Institute of Oceanography and Fisheries (NIOF) and Safier Hotel area in Hurghada city (the most important regions in Egypt), were measured by gamma ray spectrometry using NaI(Tl) detector. The values of specific activity varied from 7 ± 1 Bq kg-1 to 53 ± 4 Bq kg-1, 6 ± 1 Bq kg-1 to 32 ± 6 Bq kg-1, and from 167 ± 11 Bq kg-1 to 1120 ± 63 Bq kg-1 for 226Ra, 232Th and 40K, respectively. The heavy metals have been measured and analysed by atomic absorption spectrometer. The major range values of heavy metals concentrations in marine sediment samples were: Cu (10.5-78.0 μg g-1), Zn (21-150 μg g-1), Pb (30-53 μg g-1), Cd (2.50-4.00 μg g-1), Fe (5100-13150 μg g-1), Mn (118-298 μg g-1), Ni (17-36 μg g-1) and Co (16-18 μg g-1). The total organic matter (TOC) and carbonates (CaCo3) distribution have been measured at some locations. Also, the frequency distribution and the value of (232Th/226Ra), (232Th/40K) and (226Ra/40K) ratio for all measured samples were determined. Additionally, evaluations have been made of the radiological hazards and the results are diagrammed by Surfer program in maps. © Penerbit Universiti Sains Malaysia, 2019

A Comparative Study of the Radiological Hazard in Sediments Samples from Drinking Water Purification Plants Supplied From Different Sources

The natural radiation level has been determined for 135 sediment samples from forty-six drinking water purification plants supplied from different sources (Nile River, Ibrahimia Canal and Bahr Yousif Canal) with an aim of evaluating the radiation hazard. The concentration of natural radionuclides (226Ra, 232Th and 40K) has been investigated by using gamma spectrometry (NaI (Tl) 3″x 3″) detector. The results showed that the concentrations of average activity in the sediment samples collected from drinking water purification plants supplied from Nile River, Ibrahimia Canal and Bahr Yousif Canal are (29±2, 30±2 and 240±8 Bq kg-1), (47±3, 46±8 and 258±12 Bq kg-1) and (28±2, 27±3 and 219±18 Bq kg-1) for 226Ra, 232Th and 40K, respectively. In general, the distributions of average activity concentrations of samples under investigation are within the world values although some extreme values have been determined. Radiological hazard effects such as: absorbed dose rate (D), outdoor and indoor annual effective dose equivalent (AEDE), radium equivalent activities (Raeq), hazard indices (Hex and Hin), gamma index (Iγ), excess lifetime cancer risk (ELCR) and annual gonadal dose equivalent (AGDE) for the corresponding samples were also estimated

A Comparative Study of the Radiological Hazard in Sediments Samples from Drinking Water Purification Plants Supplied From Different Sources

The natural radiation level has been determined for 135 sediment samples from forty-six drinking water purification plants supplied from different sources (Nile River, Ibrahimia Canal and Bahr Yousif Canal) with an aim of evaluating the radiation hazard. The concentration of natural radionuclides (226Ra, 232Th and 40K) has been investigated byusing gamma spectrometry (NaI (Tl) 3″x 3″) detector. The results showed that the concentrations of average activity in the sediment samples collected from drinking water purification plants supplied from Nile River, Ibrahimia Canal and Bahr Yousif Canal are (29±2, 30±2 and 240±8 Bq kg-1), (47±3, 46±8 and 258±12 Bq kg-1) and (28±2, 27±3 and 219±18 Bq kg-1) for 226Ra, 232Th and 40K, respectively. In general, the distributions of average activity concentrations of samples underinvestigation are within the world values although some extreme values have been determined. Radiological hazard effects such as: absorbed dose rate (D), outdoor and indoor annual effective dose equivalent (AEDE), radium equivalent activities (Raeq), hazard indices (Hex and Hin), gamma index (Iγ), excess lifetime cancer risk (ELCR) and annual gonadal doseequivalent (AGDE) for the corresponding samples were also estimated.Key words: Drinking water purification plants, Sediment, Radiological hazard indice

Influence of Reaction Time, Reducing Agent and Zinc Precursors on the Morphological Structures of Zinc Oxide

ZnO either nanoparticles or nanorods were synthesized via sol-gel technique. Many factors were studied and optimized in order to obtain different morphological structures of nano-ZnO. Effect of reaction time (3, 6, 12, 24 and 48 hours) has been studied to optimize the best preparation condition. Reducing agent (NH3, NaOH and KOH) is one of the factors affect on morphological structures, which has been studied in this work. Other effect has been studied in this work is zinc precursors such as Zn (NO3)2, ZnAc2, ZnCl2, and ZnBr2. The morphological structures of prepared ZnO were revealed using scanning electron microscope (SEM) and the aspect ratios were calculated. x-ray diffraction (XRD) patterns exposed a highly crystallized wurtzite structure and used for identifying phase structure and chemical state of ZnO under different preparation conditions

Estimate the absolute efficiency by MATLAB for the NaI (Tl) detector using IAEA-314

This works amid to calculating the absolute efficiency at any interesting γ-energy in the energy range between 10 and 1764 keV. by using fit function which has been developed to calculate theoretically the absolute γ-ray detection efficiencies of a cylindrical NaI(Tl) crystal. Efficiency of the NaI(Tl) calculator is a program built in MATLAB by the author of this paper to make it easier to calculate the efficiency of standard source. The absolute γ-ray detection efficiencies have been calculated for detectors 3? x 3? inches NaI(Tl) crystal. The absolute efficiency of the NaI (Tl) detector was calculated using standard sources (IAEA-314) which have known activity of 226Ra (732 Bqkg-1) and 232Th (17.8 ppm). In this calculation, experimental and theoretical efficiencies have been calculated. The uncertainties of efficiency calibration have been calculated also for quality control. Measurements were performed with calibrated point source. Gamma-ray energies under consideration were 0.356, 0.662, 1.17 and 1.33 MeV. Efficiency function was obtained by applying Weibull Model equation to the experimental efficiency data which give Best agreement between experimental and theoretical absolute detection efficiencies of 3×3-inch detector for gamma energy. © 2019 Author(s)

Radiation Hazards and the Cancer Risk Assessments in the Sediments of Timsah Lake, Egypt

Timsah Lake is one of the most fish productive lakes in Egypt. It is located at the midpoint of Suez Canal with surface area of about 16 km2. The lake receives about 833,000 m3daily of wastewater and sewage wastes from agriculture, industry and domestic drains. The activity concentrations of the natural radionuclides; 238U, 232Th and 40K were measured using gamma-ray spectrophotometer at 24 stations covering the whole area of the lake and the Western Bay. The average activities of 238U, 232Th and 40K were; 21.66 ± 11.20, 21.42 ± 11.68 and 200.30 ± 141.10 Bq/kg respectively. The averages of radiation hazard parameters; the absorbed and effective dose rate (D), the annual effective dose equivalent (AEDE), radium equivalent (Raeq), the external hazard index (Hex) and the representative level index (Iγr) were; 30.85 nGy h-1, 37.84 μSv/y, 67.02 Bq/kg, 0.18 (lower than the unity) and 0.23 respectively. The distribution patterns showed significant high variations in the radionuclides activities and the hazard parameters between the investigated stations. The Western Bay stations and the path zone interlinked between the bay and the lake showed the high radionuclide activities and high radiation hazards indicating to the sewage wastes and wastewater runoff are the essential sources of the high natural radionuclide activities and radiation hazards. The average of the excess lifetime cancer risk (ELCR) was 132.43 × 10-6significantly lower than the worldwide average. The highest recorded level of ELCR was reached 308.38 × 10-6observed in the interlink zone between the bay and the lake away from fishing stations and recreational zones. Statistical analyses indicated that the radionuclides 238U and 232Th are the sources of the elevated radiation hazards with nearly equal intensities. © 2020. All Rights Reserved