土木工程专业英语论文翻译.pdfVIP

文档来源为:从网络收集整理.word版本可编辑.欢迎下载支持. 山东农业大学 土木工程专业英语论 文翻译 英译汉 LC 文档来源为:从网络收集整理.word版本可编辑.欢迎下载支持. Assessment of natural radioactivity levels and radiation hazards due to cement industry Abstract The cement industry is considered as one of the basic industries that plays an important role in the national economy of developing countries. Activity concentrations of 226 Ra, 232Th and 40K in Assiut cement and other local cement types from different Egyptian factories has been measured by using γ-ray spectrometry. From the measured γ-ray spectra, specific activities were determined. The measured activity concentrations for these natural radionuclides were compared with the reported data for other countries. The average values obtained for 226 Ra, 232Th and 40K activity concentration in different types of cement are lower than the corresponding global values reported in UNSCEAR publications. The manufacturing operation reduces the radiation hazard parameters. Cement does not pose a significant radiological hazard when used for construction of buildings. Keywords: Natural radioactivity; Cement; Raw materials; Radiation hazards 1. Introduction The need for cement is so great. That it considered a basic industry. Workers exposed to cement or its raw materials for a long time especially in mines and at manufacturing sites as well as people, that spend about 80% of their time inside offices and homes (Mollah et al., 1986; Paredes et al., 1987) result in exposure to cement or its raw materials being necessary reality so we should know the radioactivity for cement and its raw material. There are many types of cements according to the chemical composition and hydraulic properties for each one. Portland cement is the most prevalent one. The contents of 226 Ra, 232Th and 40K in raw and processed