Search Results

You are looking at 11 - 15 of 15 items for

  • Author or Editor: S. Mohan x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract  

A two step precipitation using ammonium carbonate and oxalic acid as the precipitants for thorium and iron is developed for the purification of 233U. Ammonium carbonate is added to the feed to increase the pH of the solution. The effect of pH on the solubility of U, Th and Fe in an excess of ammonium carbonate is studied. This indicates that the solubility of Th and Fe is minimum at pH 7 and the recovery of uranium is maximum. The effect of the concentration of thorium and iron on the recovery of uranium at pH 7 is studied. This indicates that the ammonium carbonate precipitation tolerates 2 g/l of thorium and 10 g/l of iron keeping losses of uranium to a minimum. If the feed solution contains more than a tolerable concentration of thorium the precipitation is followed in two steps: (1) Bulk of the thorium is removed by oxalate precipitation, (2) the remaining thorium and iron in the supernatant are removed by ammonium carbonate precipitation. A flow sheet is proposed for the purification of 233U from thorium and iron present in a strip product concentrate obtained during the reprocessing of irradiated thorium rods.

Restricted access
Journal of Radioanalytical and Nuclear Chemistry
Authors:
A. Palamalai
,
S. Mohan
,
M. Sampath
,
R. Srinivasan
,
P. Govindan
,
A. Chinnusamy
,
V. Raman
, and
G. Balasubramanian

Abstract  

Some batches of233U oxide product obtained from the reprocessing treatment of irradiated thorium rods, called J-rods in our plant, have been found to contain thorium as much as 85% and iron above 5% as impurities. This product has to be purified before sending for fabrication of the fuel. The present purification method consists of the following three steps: (1) preferential dissolution of U3O8 as compared to thoria, (2) a novel solvent extraction process, and (3) preferential precipitation of Th as oxalate leaving behind the entire U in the filtrate. Development and application of the present purification method to the above233U oxide proxduct are presented in this paper.

Restricted access

A new quantitative densitometric high-performance thin-layer chromatographic (HPTLC) method was developed and validated for the analysis of ranolazine (RZ) both in bulk and formulations. RZ was separated and identified on silica gel 60 F254 HPTLC plates with butanol—acetic acid—water (6:2:2 v/v) as the mobile phase. Densitometric quantification was performed at λ = 270 nm by reflectance scanning which facilitated well-resolved band for the main drug (RF 0.56 ± 0.02). Response to RZ was a linear function of concentration in the range of 100–400 ng, with a correlation coefficient, slope, and intercept of 0.99912 ± 0.00017, 8.684 ± 0.582, and 492.147 ± 2.67, respectively. The minimum amount of RZ that could be authentically detected and quantified was 14.90 and 49.67 ng band−1, respectively. Additionally, the peak identities as well as the purities were confirmed by mass spectrometry. The electrospray ionization (ESI+) mass spectra showed the [M + H]+ ion for RZ detected at m/z 428.3 being acquired directly from the sample bands by an elution-based interface. The proposed method was validated with respect to linearity, precision, accuracy, and specificity.

Restricted access
Journal of Thermal Analysis and Calorimetry
Authors:
R. Sridarane
,
G. Raje
,
D. Shanmukaraj
,
B. Kalaiselvi
,
M. Santhi
,
S. Subramanian
,
S. Mohan
,
B. Palanivel
, and
R. Murugan

Abstract  

The understanding of molecular level structural information of phosphate glasses is very much essential. The unique microwave-absorbing ability of NaH2PO4·2H2O was found to be very useful for preparing crystal and glassy sodium super ionic conductors (Nasicon's) as a component of batch mixtures. In this work NaPO3 glass was prepared by both conventional melt quench and microwave heating from NaH2PO4·2H2O as a starting material. The structure of NaPO3 glass and their structural evolution upon heating through glass transition were probed by combination of complementary techniques like differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR) and thermo-Raman spectroscopy.

Restricted access
Acta Phytopathologica et Entomologica Hungarica
Authors:
A. Kamalakannan
,
L. Mohan
,
K. Kavitha
,
S. Harish
,
R. Radjacommare
,
S. Nakkeeran
,
V. K. Parthiban
,
R. Karuppiah
, and
T. Angayarkanni

Five isolates of Trichoderma viride, Pseudomonas fluorescens and four isolates of Bacillus subtilis were evaluated for their ability to control Rhizoctonia solani, the causal agent of stem and stolon rot of peppermint (Mentha piperita Lin.). Of the various isolates of T. viride, P. fluorescens and B. subtilis tested, TVUV10, PFMMP and BSG3 showed the maximum inhibition of mycelial growth of R. solani. Among these isolates, P. fluorescens, PFMMP recorded the highest inhibition zone against R. solani in vitro and was very effective in reducing disease incidence in greenhouse condition. The effective isolates were evaluated for their ability to induce defense related enzymes and chemicals in plants. Increased activity of phenylalanine ammonia lyase (PAL), peroxidase (PO), polyphenoloxidase (PPO) and total phenolics were recorded in the biocontrol agents pretreated peppermint plants challenged with R. solani. P. fluorescens isolate PFMMP recorded early and increased synthesis of all defense related enzymes and total phenol. Thus, the present study shows that application of biocontrol agents; induce defense related enzymes involved in phenyl propanoid pathway in addition to direct antagonism which collectively contribute for enhanced resistance against invasion of R. solani in M. piperita.

Restricted access