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Introduction: Natural organic matters (NOMs) existing in water resources led to various problems such as formation of disinfectant by-products (DBPs). Humic matters like humic acid (HA) are component of NOMs that should be removed from water. Advanced oxidation process (AOPs) is one of the NOMs removal methods. The aim of this study was to survey the degradation of humic acid by electron beam irradiation/Mn II ion from aqueous solutions. Materials & Methods: This experimental study was performed in laboratory batch study. In this study, effect of pH (4 to 10), different doses of electron beam radiation (1 to 15 kGy), initial concentration of manganese ions (0.1 to 0.4 mg/l) and the initial concentration of humic acid (10 to 50 mg/l) in degradation of humic acid were investigated. Electron irradiation was performed using an electron accelerator model TT200 (IBM company, Belgium). Residual concentrations of humic acid in the samples were determined by spectrophotometer UV/Visible (Optima SP-3000 Plus model, Japan) at wavelength of 254 nm. Results: According to results, pH changes had no effect on removal efficiency of humic acid. Results showed that increase of absorbed dose led to increase of removal efficiency. With increase of MnII ion concentration to 0.2 mg/l, removal efficiency was increased but in higher concentrations, removal efficiency decreased. So that in concentration of 0.2 mg/l and 0.4 mg/l of MnII ions, removal efficiencies were equal to 65.83% and 50.26%, respectively. Survey on the experimental data showed that degradation of humic acid by e-beam irradiation in presence of MnII ions follows second-order kinetic. Conclusion: The results of this research showed that electron beam irradiation coupled MnII ions is an effective method for removal of humic acid from aqueous solutions.

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Introduction: One of the sources of natural occurring radiation was soils. The purpose of article was to determine soil pollution by radiation absorbed dose rate, radium equivalent activity, external hazard index, annual gonad dose equivalent and annual effective dose equivalent. Methods & Materials: The soil samples was located in Chahbahar city in Blouchestan of Iran, was chosen for studying of radioactivity. It was collected from twenty five points, each one in three separate places with 100 meter distance (twelve in western and thirteen in eastern sites) in the region. Then, each three soil samples were mixed and dried as one sample. The radioactivity concentration was measured in soil samples by gamma spectrometer. Results: The natural radioactivity doses of soil in studied samples resulted in average absorbed dose rate, 42.92 ±4.03 nGy h-1 radium equivalent activity, 86.79±8.26 Raeq per Bqkg- the external hazard index, 1:8231.86±327.76 the annual gonad dose equivalent, 322.9±31.6 μSvh-1 and the annual effective dose equivalent 193.15μSvh-1.The results of study were compared with the international recommended values and radioactivity measurements in soils of different countries. Conclusion: The contribution of natural radioactivity in pollution of area in comparison to ICRP was low.

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Introduction: Textile wastewaters from dyeing and finishing processes are heavily polluted with dyes, textile auxiliaries and chemicals and have a broad range of pH, high COD concentration and suspended particles. In this study, the efficiency of color and turbidity removal from synthetic textile wastewater samples were investigated by combined process of coagulation/ flocculation and electron beam irradiation. Materials and Methods: The experiments have been done on model dye solution samples which prepared from ten dyes that are supplied from Yazd Baff textile factory. Aluminum sulphate was employed to determine the optimum conditions for removal of turbidity by jar-test experiments. Then samples were irradiated by 10 MeV electron beam of Rhodotron TT200 accelerator at different doses of 1, 3 and 6 kGy. Absorption spectra of the samples were measured using UV-Vis spectrophotometer (Perkin Elmer, Lambda 25). The pH and turbidity values of the solutions were measured by a Metrohm 827 model pH meter and 2100AN turbidimeter (Hach company). Results: According to results, the degree of decoloration and turbidity removal of synthetic dye solutions increased dramatically when the alum concentration increased and reached to 64% and 90% respectively at 112 ppm. After irradiation, it is observed that absorbance at 540 nm decreased rapidly by increasing of radiation dose, because of macromolecules degradation and then decreased slowly and degree of decoloration reached to 95%. The amount of pH was decreased by irradiation and then changed very slowly or remained constant with increasing irradiation dose. Conclusion: The above results indicate that combination of coagulation/ flocculation and irradiation of 10 MeV electron beam is so effective for turbidity removal and decoloration. Coagulation process eliminates suspended particles from disperse dyes effectively, while destruction of soluble dye molecules happen by irradiation that increase decoloration efficiency considerably.

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Introduction: Ionizing radiation has long-term risks, especially cancer. Since physicians request radiological examinations for patients, they need to be aware of its benefit and also risks. The aim of this study was to assess the overall knowledge of physicians in Yazd province about the radiation risks associated with diagnostic imaging procedures. Material and Methods: In this descriptive study a questionnaire containing 25 questions was used to evaluate physicians’ knowledge of radiation doses received from radiological procedures and risks of cancer from diagnostic imaging. Their demographics such as age, sex, specialty and experience (years of practice) was also asked. Normality of data distribution was assessed using the Shapiro–Wilks test and the Kolmogorov–Smirnov test. A t-test was used for continuous variables and comparison of mean differences in scores for dichotomous variables. Spearman's correlation coefficient was carried out to look for any relationship between variables of age and experience with the knowledge of the physicians. Results: The overall mean knowledge score was 14 ± 3.15 out of 25 questions, or 56% ± 12.6%, and the scores ranged from 11.5% to 81%. The total mean score did not correlate with age and experience, but there was a significant difference (P value= 0.001) between men and women and also among the two main respondent groups, general practitioners and specialists (P value= 0.012). Physicians’ knowledge about detrimental effects of radiation including both deterministic and stochastic effects was very weak. Conclusion: The awareness of physicians about radiation is generally inadequate. Adequate training to practicing physicians about risks of radiological examinations seems needed, and revision of the curriculum of medical students in this area is recommended.

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Introduction: Textile industries produce large volume of colored dye effluents which are toxic and removal of dyes from wastewater is a significant environmental issue. Advanced oxidation process (AOPs) is alternative method for the complete degradation many organic pollutants. ZnO and TiO2 are important photocatalysts with high catalytic activity that have attracted much research attention. Material and Methods: Mixed ZnO/TiO2 was prepared with mixing of ZnO and TiO2 (20, 40, 60, 80 % (w/w)). 20 mL of dye solution (80 mgL-1 for DB71) containing the appropriate quantity of photocatalyst was magnetically stirred under UV irradiation. Photocatalytic study was carried out to evaluate the effect of UV (400 W), ZnO/TiO2 weight percent (20, 40, 60, 80 % (w/w)), pH (2.3 – 9.2), irradiation time of (10 – 70 min), initial dye concentration of (10, 40, 80 mg/L) and ZnO/TiO2 dosage of (0.2 – 1.6 g/L) on removal of dye. Dye concentration was monitored spectrophotometrically by measuring the dye absorbance at 285 nm. Results: In comparison with TiO2 or ZnO as photocatalyst, mixed photocatalyst (ZnO/TiO2) is more efficient catalyst for degradation of dye under UV irradiation Results show that approximately 90 % of Direct Blue 71 has been eliminated after 70 minutes and optimized condition ((pH = 6.4, ZnO/TiO2 (50% w/w, 1.25 g/L). Experiments showed, the noticeable decolorization of dye solution can be done without any oxidation agent with mixed ZnO/TiO2 photocatalyst.