Authors:V. Rao, I. Pius, M. Subbarao, A. Chinnusamy, and P. Natarajan
A method for the precipitation of plutonium(IV) oxalate from homogeneous solutions using diethyl oxalate is reported. The precipitate obtained is crystalline and easily filterable with yields in the range of 92–98% for precipitations involving a few mg to g quantities of plutonium. Decontamination factors for common impurities such as U(VI), Am(III) and Fe(III) were determined. TGA and chemical analysis of the compound indicate its composition as Pu(C2O4)2·6H2O. Data are obtained on the solubility of the oxalate in nitric acid and in mixtures of nitric acid and oxalic acid of varying concentrations. Green PuO2 obtained by calcination of the oxalate has specifications within the recommended values for trace foreign substances such as chlorine, fluorine, carbon and nitrogen.
Authors:S. Balasubrahmanyam, B. Viswanathan, V. Rao, and J. Kuriacose
The effect of60Co -radiation on La2CuO4 solid catalyst prepared by the ceramic method has been studied. Gamma irradiation of La2CuO4 samples has been found to increase the Cu+ content, electrical conductivities and decrease the magnetic susceptibilities of the catalyst. The results have been interpreted on the basis of the crystal field model of the structure of La2CuO4.
Authors:N. Gopinath, G. Rama Rao, V. Manchanda, and P. Natarajan
The potentiometric determination of uranium is widely carried out in phosphoric acid medium to suppress the interferences of plutonium by complexation. Owing to the complexity of the recycling plutonium from the phosphate based waste involving manifold stages of separation, a method has been proposed in the present paper which does not use phosphoric acid. Uranium and plutonium are reduced to U/IV/ and Pu/III/ in 1M H2SO4 by Ti/III/, and NaNO2 is chosen to selectively oxidize Pu/III/ and the excess of Ti/III/. The unreacted NaNO2 is destroyed by sulphamic acid and excess Fe/III/ is added following dilution. The equivalent amount of Fe/II/ thus liberated is titrated against standard K2Cr2O7. R.S.D. obtained for the determination of uranium /1–2 mg/ is 0.3% with plutonium being present upto 4.0 mg.
Authors:S. Balasubrahmanyam, B. Viswanathan, V. Rao, and J. Kuriacose
The catalytic activity of La2CuO4 for the decomposition of H2O2 was studied in detail. La2CuO4 was prepared by the ceramic method in four different ways. Gamma irradiation of the La2CuO4 samples increased their catalytic activity irrespective of the method of preparation. The enhanced catalytic activity is attributed to irradiation generated Cu+ centres on the surface of the catalyst.
Authors:Janhavi Rao, Mohan Kumar, L. Sathiyanarayanan, Savita Yadav, and V. Yadav
A sensitive, selective, precise and stability-indicating high-performance thin-layer chromatographic (HPTLC) method for analysis of sertraline hydrochloride in the bulk drug and in formulations has been established and validated. Aluminum foil HPTLC plates precoated with silica gel 60F254 as stationary phase were used with toluene-ethyl acetate-ethanol-ammonia 8:2:0.5:0.1 (ν/ν). A compact spot was obtained for sertraline hydrochloride (RF 0.33 ± 0.02). Densitometric analysis was performed in absorbance mode at 273 nm. Regression analysis of calibration data revealed a good linear relationship (r2 = 0.9996 ± 0.02) between response and concentration over the range 2000–12000 ng per band. The method was validated for accuracy, precision, linearity, limits of detection and quantification, and robustness. Sertraline hydrochloride was subjected to acidic and alkaline hydrolysis, oxidation, dry heat treatment, and photodegradation. Peaks of degradation products were well resolved from that of the pure drug and had significantly different RF values. Statistical analysis showed the method enabled repeatable and selective analysis of sertraline hydrochloride. The method can be used for routine quantitative analysis of sertraline hydrochloride in the bulk drug and in formulations.
Authors:M. Oak, S. Tamhankar, V. Rao, and S. Misra
Ten dicoccum wheats were analyzed for their physico-biochemical and milling properties to evaluate the pasta making potential. Dicoccums showed higher protein content and mixograph midline peak values compared to durum variety MACS2846. Mixographic properties of dicoccums were poor compared to durums, due to lower functional visco elastic gluten content. Dicoccums were poorer in milling properties compared to durums, due to lower test weight and thousand-grain weight. Among dicoccums, DDK 1025 showed high micro SDS sedimentation volume and strong mixographic properties, but values were still lesser compared to durum MACS 2846. HMW glutenin subunits in recently developed/released dicoccums were similar to durum parents and were different from the older dicoccums. LMW glutenin subunits, however, were similar to dicoccum parents, except in DDK 1025 which showed LMW glutenin subunits similar to durum wheat. To breed high quality dicoccum wheat for pasta products, breeders should select superior glutenin subunits composition, along with better mixograph properties, keeping morpho-botanical characteristics of dicoccum wheat.
Authors:G. V. Rama Rao, U. V. Varadaraju, S. Venkadesan, and S. L. Mannan
The high temperature superconducting compound YBa2Cu3O72212;δ (Y-123) is synthesised by sol-gel process using various precursors viz., acetate, acetate-citrate, nitrate-citrate and acrylamide. The phase purity of the final product depends on the homogeneity of the gels which intern depends on the bonding of the metal ions in the gels. The samples prepared by acrylamide and nitrate-citrate gel routes yielded phase pure Y-123 compound with better superconducting properties. The mechanism of formation of Y-123 in all these four gel routes is established by characterising the gels and intermediate phases using TG, DTA and XRD techniques. Kinetic analysis is carried out on the mass loss data using the method proposed by Phadni's and Deshpande. Avrami-Erofeev nuclei growth in case of acrylamide, diffusion controlled process in nitrate-citrate and phase boundary reaction mechanisms in case of acetate-citrate gels are found to be responsible for the formation of Y-123 phase.
Authors:M. Swarnalatha, S. Audilakshmi, C.V. Ratnavathi, B. Dayakar Rao, and J.V. Patil
Sorghum can be an alternative to corn for industrial uses, especially in drought prone areas of the world. Sorghum cultivars with high potential of grain and starch yields are needed to continuously meet the industrial demands. We have studied the genetics of grain yield and starch content of sorghum to decide the breeding procedure to develop suitable cultivars for starch industry. The genetic material from 8 × 8 diallel (28 F1 and 8 parents) was grown in a randomized complete block design, with three replications at Directorate of Sorghum Research, Hyderabad, India. Observations were recorded on seven agro-morphological and two grain quality traits including grain yield and starch content. Correlation studies revealed that the grain hardness was negatively correlated to starch and positively correlated to grain yield, panicle weight and days to flowering. Variance due to specific combining ability effects was greater in magnitude for both starch content and grain yield. Bi-parental crossing in F2 will help in getting pure lines with high starch content and high grain yield. The parents chosen for breeding program need to be good combiners for starch and grain yields to obtain superior hybrid. One MS line, 422B was a good combiner for grain yield, high starch content and 100 grain weight, and had good per se performance.
Authors:T. V. Vittal Rao, Ashok Kumar, V. N. Vaidya, and S. K. Mukerjee
A recent study has indicated the feasibility of recycling of chemicals from alkaline waste generated in the preparation of
UO3 microspheres by the internal gelation process. Present paper investigates the recycle process, the volume of the secondary
uranium waste. Result shows that prior to start the recycle process, the waste solution should be freed from uranium by ion-exchange.
Optimized experimental condition to achieve maximum reduction in the volume of uranium based waste is discussed.
Authors:D. Rao, V. Sudheendran, A. Baburajan, S. Chandramouli, A. Hegde, and U. Mishra
The Environmental Survey Laboratory is responsible for the monitoring of radioactivity due to natural and artificially produced radionuclides in a variety of samples available around the nuclear facilities at Tarapur. Standard methods of radiochemical separation and counting are followed to determine -emitters in various matrices. To make the measurement simple and detect lower levels of contamination in some of the matrices, a method was developed to measure the high energy gross -activity primarily due to 90Y in borehole water and urine samples of occupational workers by Cerenkov counting in a liquid scintillation analyser. Cerenkov counting results of borehole samples were compared with the total gross -activity measured by a low background beta-counter. The combined measurements were used to evaluate 90Sr and 137Cs levels without chemical separation or gamma-spectrometry. Cerenkov counting technique was also utilised to evaluate 40K in drinking water and intercomparison water samples. The paper presents the methodology and results of a few measurements using the technique.