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Abstract  

A rapid procedure is described for the separation and determination of 0.025 mg to 1.0 mg quantities of As(V), V(V), Mo(VI) and W(VI) from small quantities of Cu(II), Ni(II), and Zn(II) using silica gel as the selective sorbent for the cations. The individual anionic components, which remain in the supernatant solution after separation from the cations, are determined by colorimetric methods. The complete recovery of As(V) in supernatant solution has also been tested radiometrically using76As as the radioactive indicator. The sorbed cations after extraction with dilute hydrochloric acid are determined by EDTA titrations.

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Abstract  

The suitability of silica gel for the concentration of small quantities of palladium (20 μg in 500 ml) and zinc (5 μg in 500 ml) by a quick and simple method has been demonstrated. It has been found that the metals are taken up completely from their dilute solutions by silica gel, but the quantity of silica gel has to be increased with increasing volume of the solution containing the trace metals. Complete elution (desorption) of the deposited ions has been carried out with a dilute hydrochloric acid solutiion. The eluted palladium and zinc have been determined spectrophotometrically and radiometrically, respectively.

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A field experiment was carried out during the rainy (kharif) season of 2001 at the experimental farm of the Indian Agricultural Research Institute, New Delhi, India, to study the effect of date of transplanting and nitrogen on yield attributes, yields, nutrient accumulation and nitrogen use efficiencies in hybrid and non-hybrid aromatic rice. The experiment consisted of 9 treatments with 2 varieties (Pusa Basmati 1 and Pusa Rice Hybrid 10), 3 transplanting dates (3, 10 and 17 July, 2001) and 4 nitrogen levels (0, 60, 120 and 180 kg N ha-1). Pusa Rice Hybrid 10 had significantly higher values of yield attributes (panicles hill-1, panicle weight, spikelets panicle-1, filled grains panicle-1, 1000-grain weight), yields and nutrient accumulation than the non-hybrid Pusa Basmati 1. There were significant reductions in yield attributes, yields and nutrient accumulation after delayed transplanting. Timely transplanting on 3 July led to 8.4 and 19.1% higher grain yield than transplanting on 10 and 17 July, respectively. Successive nitrogen levels had a significant effect on yield attributes (except 1000-grain weight), yields and nutrient accumulation up to 120 kg N ha-1. The maximum grain yield (5.87 t ha-1) was recorded at the highest level of N nutrition (180 kg Nha-1) and was 4.2, 15.5 and 39.3% higher than in the 120 kg, 60 kg N ha-1 and control treatments, respectively. Pusa Rice Hybrid 10 also had significantly higher values of agronomic nitrogen use efficiency (ANUE) (12.5 kg grain kg-1 N applied), apparent nitrogen recovery (27.4%), physiological NUE (44.2 kg grain kg-1 N uptake), N harvest index (62.7%), N efficiency ratio (119.6 kg dry matter kg-1 N uptake) and physiological efficiency index of nitrogen (47.4 kg grain kg-1 N uptake) than non-hybrid Pusa Basmati 1.

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Abstract  

Zirconium arsenophosphate (ZAP) a new inorganic ion exchanger has been synthesized under varying conditions of precipitation. The material possesses good chemical and thermal stabilities and regeneration power. It shows no breakdown on irradiation with a gamma dose of ∼109 rad. ZAP shows high affinity for univalent ions like Rb+, Ag+ and Tl+. The Kd-values have been determined for a number of metal ions from acid media. The stoichiometry of metal ion uptake was checked using almost carrier-free radiotracers. Sixteen binary/ternary separations of metal ions are reported on a ZAP column.

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Abstract  

A number of samples of sodium phosphate glasses doped with Cd/Co or Ag chlorides were prepared and characterized by X-ray diffraction, IR spectral, ion transport and DSC studies. It was found from DSC studies that the glass transition temperature (T g) and crystallization temperature (T c) values increased with the increasing concentrations of the dopants Cd or Co chlorides. However, the T g and T c values were found to decrease when the AgCl was taken as the dopant and the following sequence is observed: T g(CoCl2)>T g(CdCl2)>T g(AgCl); T c(CoCl2)>T c(CdCl2)>T c(AgCl) These results have been discussed and explained on the basis of changes in the structure of sodium phosphate glassy matrix by the addition of different cations as dopants.

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Abstract  

The chemical effects of56Mn-recoils following neutron capture produced in mixed crystals /KMnO4–LiClO4, KMnO4–NaClO4 and KMnO4–KClO4/ have been investigated. A linear increase of initial retention with the mol fraction of perchlorate was observed which is tentatively ascribed to the tendency to form species having structures similar to that of the host matrix. The ultimate chemical fate of the manganese atom also depends on the conditions of the immediate chemical environment of the atoms /e.g. Li, Na, K/ at rest in the crystal. The results are discussed in terms of retention and non-retention reactions invoking a mechanistic model involving metal and ligand-vacancy exchange, substitution and transfer reactions.

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Abstract  

From an analysis of bibliographic data on 430 journal articles on liquid crystals covered inPhysics Abstracts 1976 and the 4729 citations to them up to the end of 1987, we have identified the geographic origin, the prominent institutions, language and journal-wise distribution of the papers, the citedness of these papers, and the distribution of citations as a time series for the highly cited papers. We have also analysed the 126 papers published by authors from India, Canada, Australia, Israel, Japan and the United Kingdom and covered inPhysics Abstracts 1978, and the 1154 citations to them up to 1987. Unlike in most other high tech areas of physics, in LC research the difference in performance between the USA and the other leading countries is not very pronounced. Publication data from 1976, 1978 and 1985 reveal that LC literature is on the rise and that the percentage share of the Soviet Union is rising fast and that of the USA is on the decline.

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