نتایج جستجو برای: radium isotopes
تعداد نتایج: 27399 فیلتر نتایج به سال:
Our long-term goal is to determine if submarine groundwater discharge (SGWD) is an important mechanism for delivering contaminants (i.e. heavy metals, organics) to harbors. We plan to accomplish this goal using a suite of naturally-occurring radium isotopes as tracers of SGWD and the dispersion of contaminants from the embayment (Buesseler/WHOI). In addition, we plan to develop a comprehensive ...
The Uranium (U) decay series provides the most important isotopes of elements Radium (Ra), Radon (Rn) and Polonium (Po) with half-lives of 1600 years, 3.8 days and 140 days, respectively. Although the chemical structure of radium is very similar to calcium, the fact that it produces a radioactive gas (Radon) complicates its handling in the laboratory and natural environment. The average concent...
Radon is a noble gas formed from the natural radioactive decay of uranium (U) and thorium (Th), natural components of the earth’s crust, which decay to radium (Ra) and then to radon (Rn). Decay chains include Ra and Rn for U; Ra and Rn for U; and Ra and Rn for Th. As radium decays, radon is formed and released into pores in the soil. Fissures and pores in the substrate allow the radon to migrat...
[1] In the Southern Ocean near the Antarctic Peninsula, Antarctic Circumpolar Current (ACC) fronts interact with shelf waters facilitating lateral transport of shelf-derived components such as iron into high-nutrient offshore regions. To trace these shelf-derived components and estimate lateral mixing rates of shelf water, we used naturally occurring radium isotopes. Short-lived radium isotopes...
A field experiment to compare methods of assessing submarine groundwater discharge (SGD) was held on Shelter Island, NY, in May 2002. We evaluated the use of radon, radium isotopes, and methane to assess SGD rates and dynamics from a glacial aquifer in the coastal zone. Fluxes of radon across the sediment-water interface were calculated from changes in measured surface water inventories followi...
Submarine groundwater discharge (SGD) into the ocean is of general interest because it acts as vehicle for the transport of dissolved contaminants and/or nutrients into the coastal sea and because it may be accompanied by the loss of significant volumes of freshwater. Due to the large-scale and long-term nature of the related hydrological processes, environmental tracers are required for SGD in...
The mean annual effective dose from natural radionuclides for users of drilled wells was estimated to be 0.41 mSv, for users of wells dug in the ground 0.05 mSv and for people using water from waterworks 0.02 mSv. The highest effective dose from drinking water was caused by 222Rn (Fig. 2) constituting 75% and 60% of the total effective dose caused by all natural radionuclides for drilled-well u...
Currently, thirty-nine astatine, thirty-nine radon,??? isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented. ∗Corresponding author. Email address: [email protected] (M. Thoennessen) Preprint submitted to Atomic Data and Nuclear ...
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