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- Author or Editor: N. Bhandari x
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Abstract
Results of phase transformations, enthalpy released and specific heat of Ge22Se78–xBix(x=0, 4 and 8) chalcogenide glasses, using differential scanning calorimetry (DSC), under non-isothermal condition have been reported and discussed. The glass transition temperature, T g, is found to increase with an average coordination number and heating rates. Following Gibbs—Dimarzio equation, the calculated values of T g (i.e. 462.7, 469.7 and 484.4 K) and the experimental values (i.e. 463.1, 467.3 and 484.5 K) increase with Bi concentration. Both values of T g, at a heating rate of 5 K min–1, are found to be in good agreement. The glass transition activation energy increases i.e. 102±2, 109±3 and 115±8 kJ mol–1 with Bi concentration. The demand for thermal stability has been ensured through the temperature difference T c–T g and the enthalpy released during the crystallization process. Below T g, specific heat has been observed to be temperature independent but highly compositional dependent. The growth kinetic has been investigated using the Kissinger, Ozawa, Matusita and modified JMA equations. Results indicate that the crystallization ability is enhanced, the activation energy of crystallization increases with increasing the Bi content and the crystal growth of these glasses occur in 3 dimensions.
Abstract
Some modifications of the stannous chloride reduction method for the estimation of inorganic phosphate reported by Berenblum-Chain are suggested. By this method, it is possible to measure 25 
g l–1 of phosphorus /P/ as inorganic phosphate in the presence of macromolecules like deoxyribonucleic acid /100 g ml–1/, as compared to 200 g l–1 of P by the original method. If a larger sample volume /30 ml/ is used, even 5 g l–1 of P can be measured.
Abstract
Unlike previously reported Zn and Se levels were found to be the same in the hair of mentally retarded children and controls. Non-essential toxic Ag concentration was low whereas that of Hg, Au and Sc rather high in mentally retarded children.
Strong anomalies in the concentration of helium, radon and gamma were observed in gases at the geochemical monitoring station, Bakreswar, West Bengal, India, about two weeks before the 7.9 M earthquake at Sichuan, China. The distance between the epicenter of the earthquake and the monitoring site is about 1800 km. This long distance preseismic observation indicates that the radius of influence of large magnitude earthquakes may be substantially large and may cut across plate boundaries. This paper presents the observed geochemical anomalies for the Sichuan earthquake and discusses empirical postulates between earthquake magnitude and its radius of influence.
The Indian Himalayan sector is well known to support the diversified bryophyte species and communities due to varied phytoclimatical conditions met within different dissected topographical zones. Many potential wilderness areas are still waiting to be explored in terms of their exuberant bryodiversity. During a bryoexploratory survey of an unexplored high-altitude area in the Garhwal Himalayan region, we came across an interesting rheophytic moss Bryocrumia L. E. Anderson. The genus Bryocrumia is represented in India by two species, viz. B. vivicolor (Broth. et Dixon) W. R. Buck and B. malabarica Manju, Prajitha, Prakashkumar et W. Z. Ma. Both of these pleurocarpous species are known to be confined in the southern part of the country. From the Indian Himalayan sector, this moss genus has never been documented earlier. Recently, B. vivicolor has been reported for the first time from the Tungnath area (2,100–3,000 m above sea level) in the Garhwal region of Uttarakhand state as a new addition to the Western Himalayan moss flora, indicating its new distributional range. This hypnaceous moss was found colonising the slopy, wet, submerged rock surfaces along small streams and seepages in mixed oak forests on way to Tungnath. The key characteristics include its rheophilic habit, stem lacking central strand, variable leaf forms, indistinct double costa and round to obtuse leaf apex with prorate tip cells. The present paper provides taxonomic details of this rare moss, representing its wide geographical distribution in India.
