Entity

Time filter

Source Type


Tereesh M.B.,Tajoura Nuclear Research Center
Radiation protection dosimetry | Year: 2013

Activity concentrations of main terrestrial radioisotopes (226)Ra, (232)Th and (40)K were measured in geological samples collected in Libya's Jabal Eghei area, in order to contribute to the establishment of a baseline map of the environmental radioactivity levels and to estimate the associated environmental risk to the population. Activity concentrations ranged from 22 to 5256 Bq kg(-1) for (226)Ra, from 11 to 221 Bq kg(-1) for (232)Th and from 132.0 to 2304 Bq kg(-1) for (40)K. Using these results, representative risk factors were calculated: the total absorbed gamma dose rate in air (ranged from 25.5 to 2434.3 nGy h(-1) with a mean value of 251.8 nGy h(-1)), the radium equivalent activity (55-5281 Bq kg(-1), with the mean value of 537 Bq kg(-1)), external hazard index (0.149-14.24, with a mean value of 1.451) and annual outdoor effective dose (31.3-2985.4 μSv, with a mean value of 308.9 μSv). Accordingly, the radiation risk is above the world average, mainly as the consequence of discovered uranium anomalies. Source


Kovacevic J.,Geological Institute of Serbia | Tereesh M.B.,Tajoura Nuclear Research Center | Radenkovic M.B.,Vinca Institute of Nuclear Sciences | Miljanic S.S.,University of Belgrade
Journal of the Serbian Chemical Society | Year: 2013

During an investigation of the Jabal Eghei area in southern Libya and the production of geological maps on a scale of 1:250 000 (Tibesti sector, sheet Wadi Eghei NF 34-1 and NF 34-2), regional prospecting for mineral raw materials was performed. A radiometric survey of the observed targets at the sites indicated two significant uranium mineralizations in rhyolites, and some smaller ones in granites that are in close contact with rhyolites. Rhyolites are located in the central part of the investigated region. They cut through granite rocks. The first mineralization is in the central part of the rhyolite region, which is mostly composed of silificated rhyolites. The second one was discovered near the granite-rhyolite contact zone, characterized by the presence of silicified breccia rocks. These findings were confirmed by laboratory measurements of more than seventy samples collected in the area, using high-resolution gamma-ray spectrometry. The concentrations of uranium in these mineralizations were found to range from approx. 50 mg kg-1 to more than 600 mg kg-1. The latter value is about 240 times above the Earth's average. Besides uranium, these measurements have also given concentrations of thorium and potassium. Additional geochemical analysis was performed on samples taken from locations where uranium anomalies were discovered using the ICP-MS technique, in which the concentrations of more than forty elements were determined. The uranium mineralizations are accompanied by increased contents of silver (up to 17 times), arsenic (up to 8 times), molybdenum (up to 50 times), mercury (up to 9 times), and lead (up to 14 times), with regards to the Clark values. These results warrant a continued investigation of this region because of potential interest in the discovery of nuclear mineral raw materials. Copyright (C)2013 SCS. Source


Al-Azmi D.,College of Technological Studies | Al-Abed T.,Chemistry and Radiochemistry Unit | Alnasari M.S.,Geological Survey and Mineral | Borham E.E.,National Center for Radiation Research And Technology | And 2 more authors.
Radioprotection | Year: 2012

Indoor radon surveys were carried out in some of the Arab countries through a Coordination Research Program (CRP) organized by the Arab Atomic Energy Agency (AAEA). The objectives of the program aim at establishing a database on indoor radon concentration levels in the region and investigating any anomalies, where they exist. The approach adopted by the survey teams to achieve public participation in accepting the radon detectors in dwellings is presented and discussed. Most of the participants in the CRP used the passive method (CR-39 plastic detectors) for long-term radon measurements, while others used charcoal detectors and E-Perm systems for short-term measurements. The results of the surveys showed that radon concentration levels in most of the dwellings were low, whilst in some old cities and in an area close to a phosphate mine the levels were found to be relatively high. © 2012 EDP Sciences. Source


Dandi A.M.A.,Tajoura Nuclear Research Center | Saion E.,University Putra Malaysia
Research Journal of Applied Sciences | Year: 2014

The monomer (2-fhiopheneacetyl chloride) with different concentrations of 9.1, 16.7, 23.1, 28.6 and 33.3 wt.% were blended with Poly vinyl Alcohol (PVA) to synthesize conducting Polythiophene (PTh) by the gamma irradiation method. The absorbed dose of 30 kGy was applied on PTh/PVA film samples at ambient conditions. On gamma irradiation, the monomer polymerized into conducting PTh by means of losing H+ ions and composing polarons, the electrical conducting agent. The morphology of PTh/PVA was studied by using SEM. The SEM image indicated well distributed PTh particles spread almost uniformly in the PVA matrix which are more or less spherical and the average particle size was found to be 0.7 μm in diameter. The optical characteristics of PTh particles were measured by the UV-visible spectrometer. The absorption peak was found to be at about 400 run with the band gap energy (Eg) which decreased from 3.19 eV at 9.1 wt.% to 2.15 eV at 28.6 wt.%. The electrical conductivity was measured by using the impedance analyzer and was found that the direct current (dc) conductivity increased from 2.6×10-5 S m-1 for 9.1 wt.% to 9.8×l0-4 S m-1 for 28.6 wt.%. © Medwell Journals, 2014. Source


Dandi A.M.A.,Tajoura Nuclear Research Center | Saion E.,University Putra Malaysia
Research Journal of Applied Sciences | Year: 2014

Electrical conducting Polythiophene (Pth) was prepared by the gamma radiation method from 28.6 wt.% 2-thiopheneacetyl chloride blended in Polyvinyl Alcohol (PVA) films. The film samples were irradiated at different doses of 0, 10, 20, 30, 40 and 50 kGy at ambient condition. This method was used without adding any type of chemical oxidizing agents. Upon gamma irradiation, the 2-thiopheneacetyl chloride monomer polymerized into conducting PTh by losing FT ions and formed conducting species of polarons. The SEM morphology of PTh/PVA composites showed that the particles have a spherical structure of about 0.7 um in diameter and spread uniformly in the PVA matrix. The UV-visible spectrophotometry and impedance analyzer were used to characterize the optical and electrical properties of PTh particles, respectively. The absorption peak was established at 400 run. The optical band gap energy (Eg) decreases with the increase of the absorbed dose from 2.35 eV before starting the irradiation process to 2.15 eV at 30 kGy. The dc electrical conductivity through the PTh/PVA composites increases with the increasing of absorbed dose from 2.8×10-4 S m-1 at 0 kGy to 9.8X10-4 S m-1 at 30 kGy. © Medwell Journals, 2014. Source

Discover hidden collaborations