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- Author or Editor: P. Singh x
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Abstract
Extraction of U(VI), Zr(IV) and Th(IV) has been investigated from perchlorate media using 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC-88A) dissolved in toluene. The extraction of U(VI), Zr(IV) and Th(IV) was found to be quantitative in the pH range 1.6 to 3.2, 2.0 to 4.7 and 2.3 to 3.8, respectively, with 3.0.10-3, 5.6.10-4 and 1.0.10-2M PC-88A dissolved in toluene. U(VI) was stripped with 4.0M HCl, Zr(IV) with 2.5M NaF and Th(IV) with 8.0M HCl from the metal loaded organic phase containing PC-88A dissolved in toluene. The probable extracted species have been ascertained by plotting log D vs. log [HR] as UO2R2 .2HR, ZrR4 .2HR and ThR4 .4HR, respectively. U(VI) was separated from Zr(IV) and Th(IV) and from other associated metals. This method was proved by the determination of U(VI) in some real samples.
Abstract
The thermodynamic behaviour of bulk metallic glass (BMG) forming melts have been studied by analyzing the temperature dependence of the Gibbs free energy difference (∆G), entropy difference (∆S) and enthalpy difference (∆H)between the undercooled melt and the corresponding equilibrium solid phases. The study is made by calculating∆G, ∆S and ∆H in the entire temperature range T m (melting temperature) to T g (glass transition temperature) using the expressions obtained on the basis of Taylor’s series expansion. The entire analysis is made for La-based five samples of BMGs; La55Al25Ni20, La55Al25Ni15Cu5, La55Al25Ni10Cu10, La55Al25Ni5Cu15, and La55Al25Ni5Cu10Co5 and a comparative study is also performed between present results and results obtained in the framework of expressions proposed by earlier workers. An attempt has also been made to study the glass forming ability for BMGs.
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.
A new lichenicolous fungus Buelliella indica colonising on the thallus of Graphis longiramea is described from the state of Nagaland, a part of the Indo-Burma biodiversity hotspot region in India. It is characterised by its brown epihymenium, much smaller ascospores with dimensions of 11.5–13.8 × 4.8–6 µm and the new host Graphis.
The role of blue green algal (BGA) biofertilizers has been limited to its relevance and utilization in rice crops, and scanty information is available on their use in conjunction with organic amendments and their influence on wheat (Triticum aestivum) . An experiment was conducted from November 2003 to April 2004 in the fields of the Indian Agricultural Research Institute (IARI), New Delhi, India to evaluate the effect of vermicompost, farmyard manure and biofertilizers (BGA and Azotobacter ) in different combinations with chemical fertilizers (N 40 P 30 K 30 ) in wheat (var. HD 2687). Selected soil biological parameters (cyanobacterial diversity/abundance, nitrogenase activity and the phototrophic biomass of soil cores) were measured. The application of vermicompost in combination with BGA biofertilizer (B+V+N 40 P 30 K 30 ) brought about a significant increase in nitrogenase activity (from 0.1 in N 80 P 30 K 30 to 2.0 nmoles mg chl −1 h −1 ), while Azotobacter + BGA (+N 40 P 30 K 30 ) treatment gave the highest values of chlorophyll (1.19 μg g −1 soil). The addition of vermicompost and farmyard manure (+N 40 P 30 K 30 ) enhanced cyanobacterial abundance, and cyanobacterial genera such as Nostoc, Anabaena, Calothrix, Oscillatoria and Phormidium were the dominant forms observed under the wheat crop. The synergistic effect of organic amendments, biofertilizers and chemical fertilizers, especially BGA inoculants, advocates their utilization in wheat crops to improve soil fertility.
A new lichenicolous fungus Melaspilea nitidochapsae colonising on the thallus of Nitidochapsa leprieurii (Mont.) Parnmen, Lücking et Lumbsch is described from India. The new species differs from other known species colonising lichen family Graphidaceae by having completely carbonised exciple, hyaline to pale brown transversely 1-septate ascospores and a different host.
In the present study on the self-incompatibility in inbred lines of ten local Indian cultivars (Pusa Chetki, Chetki Long, Aushi, Alipur Local White, Jaunpuri, Half Red, Scarlet Red, Chinese Pink, Desi Red and Khasi Kata) of radish ( Raphanus sativus L.), Pusa Chetki, Chetki Long, Aushi, Alipur Local White and Jaunpuri were classed as selfcompatible, Half Red, Scarlet Red and Chinese Pink as intermediate and Desi Red and Khasi Kata as self-incompatible. The highest number of germinated pollen grains and pollen tubes was observed in Pusa Chetki, followed by Alipur Local White, Jaunpuri, Aushi and Chetki Long. The discrepancy in the number of germinated pollen grains in the stigmas may be explained by the inhibitory action of large numbers of self-incompatible pollen grains on the stigma. When two lines, Desi Red and Khasi Kata, were grown under different temperature and photoperiod conditions, no breakdown in self-incompatibility was observed, and the flowering periods of these lines are naturally well synchronized. It is well known that uniform and effective cross-pollination may be of great importance for obtaining a high quantity of hybrid seed in self-incompatible types. To produce single cross hybrid seed, the inbred lines Desi Red and Khasi Kata can be used as parental lines.
Abstract
Selected numbers of representative banded iron formations collected from various mines of iron ore supergroups were investigated using ore microscopy and Mössbauer spectroscopy. The ore microscopy results have been corroborated and compared with Mössbauer spectroscopy outcome. Different iron-bearing minerals present in these banded iron-formations have been quantified by 57Fe Mössbauer spectroscopy. The obtained results have been discussed on the basis of degree of martization and goethite-hematite abundance.
Castration of the catfish Clarias batrachus in late preparatory-early prespawning phase (April&May) caused time-dependent stimulatory effect on morphology, weight, and in the concentrations of biochem- ical correlates, such as total proteins, fructose, hexosamines and sialic acid in the seminal vesicle (SV). The peak changes were noticed on week 4 of castration. The hyperactivity was related to augmented pro- duction of testosterone by the SV of castrates with the levels significantly high from week 3 onwards. As a result, serum testosterone level fluctuated with a significant decrease in the first and fifth weeks, a sig- nificant increase in the third week, and no significant difference in the second and fourth weeks. Serum E2 level decreased significantly throughout. Cyproterone acetate treatment (CA; 1 mg/fish daily for 21 days) from the second day of castration decreased the size and weight of the SV and the concentrations of total proteins, hexosamines, fructose and sialic acid. The antiandrogen treatment did not alter serum testosterone level but the E2 level was significantly decreased. It is concluded that the hypersecretory activity of the SV in castrates is a sequel to local synthesis and action of testosterone and the effect could be prevented by CA by blocking androgen actions.
The impact of nitrogen-fixing blue-green algal (BGA) strains, namely Anabaena variabilis, Aulosira fertilissima, Nostoc muscorum and Tolypothrix tenuis , was studied at different levels of nitrogen fertilizer on specific soil parameters such as microbial populations, pH, EC, redox potential, chlorophyll, dehydrogenase and nitrogenase activity under a rice crop. The inoculation of the soil with BGA strains resulted in higher microbial populations (BGA, bacteria, fungi and actinomycetes) and had a significant influence on redox potential. A significant increase in soil chlorophyll, dehydrogenase and nitrogenase activity was observed during crop growth due to BGA application.
