Uranium from Africa has long been a major source of fuel for nuclear power and atomic weapons, including the bomb dropped on Hiroshima. In 2002, George W. Bush claimed that Saddam Hussein had "sought ...significant quantities of uranium from Africa" (later specified as the infamous "yellowcake from Niger"). Africa suddenly became notorious as a source of uranium, a component of nuclear weapons. But did that admit Niger, or any of Africa's other uranium-producing countries, to the select society of nuclear states? Does uranium itself count as a nuclear thing? In this book, Gabrielle Hecht lucidly probes the question of what it means for something--a state, an object, an industry, a workplace--to be "nuclear." Hecht shows that questions about being nuclear--a state that she calls "nuclearity"--lie at the heart of today's global nuclear order and the relationships between "developing nations" (often former colonies) and "nuclear powers" (often former colonizers). Nuclearity, she says, is not a straightforward scientific classification but a contested technopolitical one.Hecht follows uranium's path out of Africa and describes the invention of the global uranium market. She then enters African nuclear worlds, focusing on miners and the occupational hazard of radiation exposure. Could a mine be a nuclear workplace if (as in some South African mines) its radiation levels went undetected and unmeasured? With this book, Hecht is the first to put Africa in the nuclear world, and the nuclear world in Africa. Doing so, she remakes our understanding of the nuclear age.
Graphitic carbon nitride (g-C.sub.3N.sub.4) has been paid increasingly attentions in U(VI) removal due to the visible-light response, whereas the high recombination of photogenerated electron and ...holes limited the actual environmental application. Herein, Z-scheme MoS.sub.2/g-C.sub.3N.sub.4 heterojunction was fabricated to enhance removal of U(VI) from aqueous solution. The microscopic and spectroscopic characterizations showed that addition of MoS.sub.2 on surface of g-C.sub.3N.sub.4 increased separation efficiency of photogenerated charge, decreased the bandgap and improved the intensity of light adsorption. Approximate 82% of UO.sub.2.sup.2+ was photo-reduced by MoS.sub.2/g-C.sub.3N.sub.4 after 1 h of light irradiation at pH 4.5. The high effective photocatalytic reduction of U(VI) on MoS.sub.2/g-C.sub.3N.sub.4 was attributed to ·O.sub.2.sup.- radials according to quenching experiments. XPS analysis showed that the adsorbed U(VI) was photo-reduced into U(IV). These findings are crucial for the design of C.sub.3N.sub.4-based composites with high efficient photocatalytic performance and exclusive selectivity into actual environmental cleanup.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Soil covering method is commonly used in uranium tailings pond beach management, but the material used and environmental factors can affect long-term safety and stability. The study tested CaCl.sub.2 ...solution concentrations for desiccation crack development and radon retardation in red clay. Four red clay radon shielding layer specimens with varying solution concentrations underwent drying tests. Results showed that soil mineral composition remained unchanged and the crack rate decreased with increased CaCl.sub.2 solution concentration; the best radon retardation effect is achieved by mixing CaCl.sub.2 solution with 3% concentration. These findings can guide effective radon treatment on uranium tailing pond beach surfaces.
The MoS.sub.2@TiO.sub.2 hollow sphere heterostructures (MoS.sub.2@THS) were synthesized and used for photocatalytic reduction of U(VI) from wastewater under visible light. The optimum ...MoS.sub.2@THS-12 shows the highest photocatalytic reduction rate (irradiated for 80 min) with excellent recyclability and stability, which is approximately 4.1 times as much as the pure MoS.sub.2. The improved photocatalytic activity of MoS.sub.2@THS-12 is mainly due to the II-types heterojunction formed between MoS.sub.2 and THS. Meanwhile, the photogenerated electrons and superoxide radical are important active species in the photoreduction U(VI) process. The results provide an effective strategy for uranium resource utilization and pollution abatement.
In this study, an investigation has been carried out on the potential of radon, thoron and natural radioactive content by collecting soil samples from the Deccan land of Kolhapur district, India. The ...mean value of radon mass exhalation rates is 12.66 ± 1.07 mBqkg.sup.-1h.sup.-1 and mean thoron surface exhalation rate is 2300 ± 261 Bqm.sup.-2h.sup.-1. The mean value of Radon emanation factor is 5.18%. The mean activity concentrations of .sup.238U, .sup.232Th and .sup.40K in the soil samples are 9.33 ± 0.45 Bqkg.sup.-1, 16.60 ± 0.77 Bqkg.sup.-1 and 66.15 ± 4.33 Bqkg.sup.-1 respectively and well below the value recommended by UNSCEAR 2000.
PDF
