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Journal of Radioanalytical and Nuclear Chemistry
Authors: R. Aliev, V. Bobrov, St. Kalmykov, M. Melgunov, I. Vlasova, V. Shevchenko, A. Novigatsky, and A. Lisitzin

Abstract  

Natural 210Pb and artificial 137Cs were applied for estimation of sedimentation rates for 14 cores collected in the White Sea, Franz Victoria and Novaya Zemlya troughs. Vertical profiles of 137Cs with high resolution (0.5–1 cm) are presented for 18 cores. The agreement between sedimentation rates obtained from 210Pb age-dating and 137Cs vertical profiles was found. Two maxima of 137Cs specific activity were observed in the cores near the North Dvina and Onega mouths, which may be correspond to the Chernobyl accident and global fallouts in early 1960-s.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: D. Leipunskaya, S. Savosin, V. Drynkin, A. Aliev, Ya. Finkelshtein, N. Popova, and E. Zemchikhin

Abstract  

The difficulties of determining gold in rocks and ores are due to two causes: low gold concentrations in rocks (Clark 1 to 4·10−7%), and non-uniform distribution of gold in ores. A method is proposed which is based on neutron activation of the lead alloy obtained by cupel melting in the procedure of determining gold by cupel assay. Samples of 50 to 100 g are used for cupel melting. Such large samples guarantee their representativeness. Discs of 2 to 3 g are cut from the lead alloy block and activated in a neutron flux of 1011 to 1013 n·cm−2 sec−1. The gold content is determined from the photopeak of198Au using a standard for comparison. The sensitivity of the method is 0.02 g/metric ton, its accuracy at a gold content in the order of 1.0 g/metric ton is 10% relative. The method is distinguished by the fact that it is fast and requires little labour.

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Abstract  

DMA and solid state 13C NMR techniques were used to measure historical parchment samples within the framework of the project (MAP) Micro Analysis of Parchment (EC contract No. SMT4-96-2101) in collaboration with the School of Conservation in Copenhagen. DMA was used in both thermal scan and creep modes. Thermal scans provided information on the transitions associated with the collagen polymer. Microthermal analysis was also used to obtain information on the topography and thermal conductivity of sample areas of 100 μm. Localised heating enabled measurements of softening transitions in the sample. This behaviour is influenced by the chemical composition of parchment. 13C NMR provided information on the carbon atoms associated with the polypeptide chains of the collagen in parchment. The behaviour of samples immersed in water and measured in DMA creep mode was used to measure the shrinkage behaviour of the parchment samples. The different but complementary techniques provided a means for characterising the physicochemical state of parchment samples.

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