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Abstract  

A method is described for the simultaneous multielement determination of yttrium and lanthanides at microgram level. This is based on the preconcentration of these lanthanides on to 1-(2-pyridylazo)-2-naphthol (PAN) modified naphthalene. The optimal conditions for quantitative preconcentration viz., pH, amount of PAN modified naphthalene, time of stirring and aqueous phase volume were systematically evaluated. The quantitation of lanthanides was carried out by energy dispersive X-ray fluorescence analyzer, employing241Am annular source, via their characteristic K X-rays. The developed procedure gave reliable results in the analysis of xenotime samples.

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Abstract  

Determination of copper/II/ by radiochemical displacement of labelled cobalt from cobalt-o-hydroxybenzaldehyde isonicotinoyl hydrazone /Co-BIH/ complex has been studied. Borate buffer of pH 5 was found to be a suitable medium for quantitative displacement. 10–70 g of copper could be determined. The effect of various foreign metal ions on the determination has also been studied.

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Abstract  

5–25 g of copper has been determined by exchange with zinc-65 labelled zinc sulphide. The effect of diverse ions on the determination has also been reported.

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Abstract  

A simple method is reported in this paper to estimate229Th in the presence of228Th. The total activity of229Th and228Th was determined by following the alpha activity growth (using a liquid scintillation counter and proportional counter) of purified thorium samples. The activity ratio of229Th/228Th was determined by alpha spectrometry. From the initial total activity and ratio, disintegration rates of229Th and228Th were calculated. The values obtained for the activities have a precision better than ±2%.

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Abstract

This communication deals with the waste heat recovery from the industrial refrigeration and air-conditioning system by introducing Canopus heat exchanger. There is a considerable amount of low-grade heat available in large-capacity systems. To recover this low-grade heat, a Canopus heat exchanger is introduced between compressor and condenser components. The system feasibility is studied with various operating parameters and its effect on heat recovery factor and overall COP of the system. The parametric results obtained for different eco-friendly working fluids, such as R-134a and R-507a, have been presented. It is found that, in general, overall COP of the system is improved without affecting the actual performance of the system. The potential of low-grade heat availability is increased with increasing cooling capacity.

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Abstract  

Zirconium molybdoarsenate (ZrMAs), an inorganic ion exchanger, has been synthesized and the suitable conditions to separate cesium-137 from fission products waste solution are suggested.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: P. Sarita, G. Naga Raju, A. Pradeep, Tapash Rautray, B. Seetharami Reddy, S. Bhuloka Reddy, and V. Vijayan

Abstract  

Trace elemental imbalance in human beings is postulated to exert action, directly or indirectly, on the carcinogenic process. The objective of this study was to evaluate the levels of trace elements in blood sera of breast cancer patients and analyze their alteration with respect to healthy controls. This work was also intended to establish the role played by the trace elements in carcinogenic process. Particle induced X-ray emission (PIXE) technique was used for trace elemental analysis of blood sera of breast cancer patients and healthy controls. The PIXE measurements were carried out using a 2.5 MeV collimated proton beam from the 3 MV Tandem Pelletron accelerator at Institute of Physics, Bhubaneswar, India. On comparing the trace elemental content in the sera of breast cancer patients with those of control subjects, significant variations were observed in the levels of most of the trace elements. The serum levels of almost all the elements except Fe and Cu were observed to be depressed in cancer patients with respect to normal subjects. However, this variation was significant only for Ti (P < 0.00005), Cr (P < 0.005), Mn (P < 0.0005), Ni (P < 0.01), Zn (P < 0.000001), and Se (P < 0.05). On the other hand, significant elevations were observed in serum Fe (P < 0.05) and Cu (P < 0.005) levels in cancer patients. The findings presented in this paper give guidelines for future study into the possible roles and interactions of essential trace elements in the breast carcinogenic process.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: A. Rufus, H. Subramanian, S. Velmurugan, Santanu Bera, G. Reddy, V. Sankara Sastry, and S. Narasimhan

Abstract  

A pinhole developed near the tube sheet in the steam generator (SG) tube of a pressurised heavy water reactor (PHWR) caused leak of primary coolant containing radioactive contaminants (137Cs, 134Cs and 60Co) to the shell side. The sludge collected from the tube sheet region was found to have adsorbed these radionuclides at the high temperature (230-240 °C) that prevailed in the SG. An attempt has been made to evaluate the quantity of activity retained in the various oxide phases that constitute the sludge and their mode of pick-up. The sludge was characterized by XRD and XPS, which showed the presence of various oxides of iron, copper and nickel along with the silicates of calcium, magnesium and aluminum. Gamma-spectrometry of the sludge confirmed the presence of 137Cs134Cs and 60Co to an extent of 7.6, 1.3 and 0.9 mCi/g of sludge, respectively. Selective dissolution in various EDTA based formulations and equilibration with nitric acid and magnesium chloride solutions helped to understand the quantity of activity adsorbed by various constituents of the sludge. It was concluded that a major portion of cesium was picked up by a reversible ion exchange process on various oxide constituents and about 10% by an irreversible specific adsorption process on insoluble silicates. Also, it was proved that 60Co was specifically adsorbed over the oxides of iron and nickel.

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A field experiment was conducted in Vertisols at Bijapur during 1994-96 to study the effect of tillage practices and integrated nutrient management on winter sorghum yield and soil nutrient availability. The increase in winter sorghum yield with deep tillage over medium and shallow tillage was 27 and 57% in 1994-95 as compared to 18 and 34% in 1995-96. Deep tillage resulted in 22 and 45% higher yield as compared to medium and shallow tillage in the pooled data. This was mainly due to conservation and increased availability of moisture and nutrients, i.e. N, P and K. The higher availability of nutrients in the topsoil (0-0.15 m) as compared to the subsoil (0.15-0.30 m) was due to the application of nutrients in the topsoil layer and the higher rate of mineralization. Among the organic materials applied, Leucaena loppings at 2.5 t ha-1 led to a significantly (9%) higher yield (1636 kg ha-1) over vermicompost (1500 kg ha-1) and was on par with farmyard manure (1572 kg ha-1) in the pooled data and during both years of the study. The higher percentage increase in grain yield with Leucaena application was due to the better moisture conservation and availability of major nutrients, i.e. N, P and K. Winter sorghum responded significantly to N application at 25 kg ha-1 in 1994-95, whereas in 1995-96 and in the pooled data the response varied up to 50 kg N ha-1. In the pooled data, the grain yield increased by 17 and 24% with the application of 25 and 50 kg N ha-1 compared with the control. The higher yields obtained with the application of nitrogen were due to the better availability of nutrients, especially N, as these soils are low in available N.

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Abstract  

Three ferromanganese crusts from different locations of the Indian Ocean were analysed by neutron activation analysis using thek 0 method (k 0 NAA method) for studying the distribution of some trace elements along with Fe and Mn. Another crust from the Lau basin of the Pacific Ocean was investigated for comparison of the influence of different oceanic conditions on the trace element distributions in ferromanganese crusts. Variation in Co concentration along with the Mn/Fe ratio were discussed in terms of the hydrogenous/hydrothermal nature of the crusts. The normalised REE content was used to identify possible anomalies. The observed Ce anomaly is discussed in the light of the depositional environment. The precision and accuracy of the method were confirmed by measuring the elemental concentrations in a USGS nodule standard NOD A-1.

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