The complex exchange of fluvial, subsurface and seawater within a coastal area directly affects global biogeochemical cycles and the application of isotopic tracers, mainly natural radionuclides from U and Th series, is a powerful tool to track sources and sinks of trace elements and nutrients to this systems. The unique Ra signature applied to quantify the
Natural rubber latex is a dispersion of natural rubber particles in water. These particles are coated with a protein layer which will stabilize the dispersion in water by forming an electric charge in the layer. Any different condition affecting this layer disturbs the stability of dispersion. Microorganism attack disturbs the protein layer and consequently the stability of the dispersion. By adding 1.2% by weight of NH3, the stability of the dispersion can be improved. The fresh latex was irradiated by Co-60 with irradiation dose of 10, 20, 30, 40 and 100 kGy. The results showed a relationship between the volatile fatty acid content (VFA, product from microorganism attack on carbohydrate) and the green strength or the physical properties of vulcanized film. Low VFA number showing a higher physical strength of the film either un-vulcanized or vulcanized. It appeared that the structure was responsible in yielding a good physical property of the film.
Monitor of natural radionuclides in aquatic raw is very important to guaranty the normal control level in the environmental medium and the human. In this report were available the concentration of 226Ra and 228Ra in Cananeia’s underground water, Iguape and Comprida Island into the south region of Sao Paulo state, by gross alpha and beta counting method. The concentration of 226Ra was variety into the interval 0.80 to 23 mBqL-1 in April/2009 (rain period) and into the interval 0.63 to 12 mBqL -1in August/2009 (dried period). The concentration of 228Ra was variety into the interval 18 to 39 mBqL-1 in April/2009 and into the interval 15 to 72 mBqL-1 in August/2009. The Activities ratio of 228Ra/226Ra was variety into the interval 3.3 to 31.7 at rain period and 1.1 to 26.7 at dried period. To compare the yield values of 226Ra and 228Ra these show high activity of the 228Ra isotope. The calculate dose no arising the reference of effective dose level available by WHO.
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