of conducting polymers based on m-nitroaniline, m-chloroaniline and m-aminophenol
by aniline initiated ammonium peroxydisulfate oxidation, has been attempted.
The IR spectra of the polymers have been studied. Thermogravimetric analysis
of the conducting polymers has been followed using a computer analysis method
LOTUS PACKAGE, developed by us for assigning the degradation mechanism. A
number of equations have been used to evaluate the kinetic parameters. The
mechanism of degradation of the conducting polymers has been explained on
the basis of their kinetic parameters.
No-carrier-added radionuclides of arsenic and selenium were produced in 16O irradiated cobalt target matrix. The initial products, formed by 59Co(16O,xn)70-73Br reaction, decayed promptly to arsenic and selenium radionuclides, which were subsequently separated by liquid-liquid extraction (LLX) using di-(2-ethylhexyl) phosphoric acid (HDEHP) and trioctylamine (TOA) as liquid ion exchangers.
Representative banded iron-formations (BIFs) from various locations of the eastern Indian geological belt were investigated
by instrumental neutron activation analysis (INAA). After pre-concentration, irradiation was carried out using a neutron flux
of 5.1·1016 m−2·s−1, 1.0·1015 m−2·s−1 and 3.7·1015 m−2s−1, with thermal, epi-thermal and fast neutrons, respectively. The activities in these samples were measured by a HPGe detector.
Ten rare-earth elements, such as La, Ce, Nd, Sm, Eu, Tb, Ho, Tm, Yb and Lu, have been qualitatively identified and quantitatively
estimated in these samples. The present investigation is an example of employing a pre-concentration method for high iron-containing
ores prior to neutron activation analysis.
The present study is performed to examine the accumulation efficiency of 51Cr(III) and 51Cr(VI) by the alkaloid piperine, derived from the fruits of Piper nigrum (Family Piperaceae) as well as using the fruit commonly known as black pepper by radiometric technique. The pH dependence
and the effect of the concentration of chromium on the accumulation have also been examined. The maximum accumulation (52%)
of Cr(III) is found by black pepper at pH 4 whereas piperine shows slight accumulation at this condition. Accumulation of
Cr(VI) by black pepper is always negligible. It has also been observed that some other constituents of the black pepper like
gum, terpenoid, etc., besides piperine is responsible for the accumulation of chromium.
Carrier free promethium was produced by proton activation in neodymium target. Extraction behavior of both the elements were
studied by HDEHP. A pronounced synergism had been observed by the binary mixture of HDEHP and PC88A. Presence of H2O2 in aqueous phase also increases the separation factor.
Authors:T. Datta Samanta, S. Laskar, D. Nayak, and S. Lahiri
Binding ability of mercury, thallium, lead and bismuth with Erythrina variegata seed protein have been investigated using tracer packet technique. Due to the lack of standard methods, inter-comparisons
have been made among three different approaches, like trichloroacetic acid (TCA) precipitation, isoelectric precipitation
and dialysis of protein after incubation with the metals. Good agreement was observed for all the cases except that of lead.
Authors:D. Nayak, T. DattaSamanta, S. Laskar, and S. Lahiri
The tracer packet technique is an efficient tool to evaluate simultaneously the behavior of some closely associated elements.
The present study has been performed to determine the binding affinity of various toxic heavy and micronutrient elements with
the proteins extracted from Erythrina variegata Linn. (Family: Leguminosae) seed by means of ‘tracer packet’ technique. Effects of buffer and pH dependence on the binding
affinity of the elements of interest have also been examined.
Authors:L. S. Probhumirashi, G. N. Natu, and S. R. Nayak
Thermal analysis of mono-, bis- and trisethylenediamine (en) complexes of Ni(II) chloride was carried out using TG, DTG and DTA techniques. The kinetic parameters were estimated from dynamic TG studies using the Coats and Redfern equation. The thermal stability of the metal-ligand (Ni-N) bond in, the complex was found to decrease with increasing Ni∶en ratio. The DTA studies showed that the loss of en was initially endothermic but became increasingly exothermic with the progress of the decomposition. The final step in the case of all the three complexes was always composite in nature causing the loss of both Cl atoms with simultaneous oxidation of Ni to NiO. The dissociation of the Ni-en bonds appears to be regulated by the “nucleation and growth” mechanism. Kinetic parameters corresponding to various steps of decomposition of all the three complexes were evaluated.
Authors:S. Lahiri, D. Nayak, A. Ramaswami, and S. Manohar
Heavy ion activation of natural terbium foil with 75 MeV 12C6+ results in the formation of carrier-free lutetium isotopes, 165–167Lu, and their corresponding decay products, 165–167Yb and 165–167Tm, in the matrix. Carrier-free lutetium and ytterbium isotopes have been separated quantitatively from terbium bulk target matrix using HDEHP liquid cation exchanger. Radiochemically pure thulium radionuclides have been obtained after the decay of ytterbium radionuclides.