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  • Author or Editor: E. Daniels x
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Abstract  

The solid state reaction between KMnO4 and zeolite-13X at a temperature below the melting point of the salt presumably results in inclusion of manganese in the zeolite. Quantitative measurements of manganese uptake at various proportions of KMnO4 in the mixture were achieved by neutron activation analysis of the Mn-zeolite.

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Abstract  

Volume diffusion of I anions in the near surface region of copper has been studied by radiotracer technique. The diffusion coefficients were determined for different I coverages on copper employing the Gruzin method of measuring the residual activity. Diffusion annealing was carried out between 303 and 673 K. The distribution of the I species in the diffusion-annealed sample was monitored by noting the residual activity of the specimen upon subjecting it to successive acid-etchings. The simultaneous evaporation losses from the I deposit are reduced by securely holding the sample coupon in between two blank copper coupons using a metal clip.

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Abstract  

Isotherms of silver uptake by zeolite-13X from AgNO3 at temperatures /323-563 K/ around the melting point of the nitrate are reported. Measurements of silver uptake have been carried out by a neutron activation method. At temperatures below the melting point the Ag+ uptake is exchange dominant while above the melting point the exchange accompanies substantial AgNO3 inclusion. The overall process of Ag+ uptake from both the powder and the melt is endothermic within the temperature range employed.

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Abstract  

Competitive uptake of Cs+, Ba2+ and Zn2+ ions from aqueous medium by zeolite-3A is studied by the radiotracer technique. Suppression Cs+ uptake in presence of Ba2+ is the maximum amongst the competitive uptakes. The simultaneous uptakes of the individual cations are considered in the light of the zeolite pore size, hydration effects and mobilities of the competing cations.

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Abstract  

Volume diffusion coefficients of I anions in the near surface region of silver have been determined using131I. The distribution of the labelled ions with depth is determined by acid etching and counting the residual activity. The coefficient of diffusion is determined for surface layers of three different thicknesses over the temperature range 373–823 K. The mechanism proposed assumes the dissociation of Ag+I in surface layer and the diffusion of I into the interstitial free space immediately beneath the surface. This process is found to be accompanied by a small negative entropy change.

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Ceratolejeunea belangeriana is added here to the liverwort flora of India from the Indira Gandhi National Park, Anamalais in the Western Ghats. A brief description together with illustrations are provided.

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The moss Actinodontium adscendens is added here to the flora of India from the Western Ghats of Peninsular India. It is described and illustrated with notes on its habitat.

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Cheilolejeunea obtusifolia, so far known only from Andaman Islands in India, is added here to the flora of the Indian mainland from the Anamalais in the Western Ghats. A brief description with an illustration and a photoplate is provided here since there is none based on any Indian material.

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Fissidens serratus, a long-lost liverwort, is rediscovered in the Indira Gandhi National Park in Anamalais in the Western Ghats in Peninsular India after nearly two centuries. Till now, the collection made by Perrottet between 1834 and 1839 in the Nilgiri Hills has been the only Indian representative of this species.

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Two Asian mosses Entodontopsis setschwanica (Broth.) W. R. Buck et R. R. Ireland and Mitthyridium cardotii (M. Fleisch.) H. Rob., so far known from the Eastern Himalaya and Northeast India, respectively for India, are added here to the moss flora of Peninsular India from the Western Ghats. Brief descriptions with illustrations are provided.

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