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  • Author or Editor: P. Banerjee x
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Seven parents (CST2002, MT34, OS-Sel-2, TKG22, AAUDT9304-14-4, B67 and Rama), their 21 F 1 s and 21 F 2 s were grown in summer 2003 in a randomized block design with three replications. Heterosis and inbreeding depression were studied for seven important yield-contributing characters (plant height, branch number plant −1 , capsules plant −1 , seeds capsule −1 , 1000-seed weight, stick yield plant −1 and seed yield plant −1 ). Maximum heterosis for seed yield plant −1 over the mid- and better-parent was recorded in CST2002×TKG22 (43.30%) and MT34×B67 (27.22%), respectively. Mid-parent heterosis for seed yield plant −1 was due to cumulative heterosis for various important component traits, such as capsules plant −1 , seeds capsule −1 and 1000-seed weight. Inbreeding depression was highest for seed yield, followed by 1000-seed weight, capsules plant −1 , branch number and plant height, indicating the predominance of non-additive genetic effects. B67×Rama exhibited significant positive heterosis in F 1 , but non-significant inbreeding depression in F 2 for seed yield. This cross can be utilized as basic material for identifying better pure lines. The clustering pattern indicated that in general genetically diverse parents exhibited more heterosis, as evident in the majority of the crosses.

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A new zeolite derivative has been prepared by interacting Th(IV) and complexone in HCl medium and neutralising with aqueous ammonia. The amorphous and siliceous derivative showed a total mass loss of 29.25% in TG for stepwise dehydration, dehydroxylation and decomposition. Heats of reaction were 1167.6 J g−1 at 88.7°C and 75.167 J g−1 at 492.5°C for loss of volatile components and decomposition respectively.29Si and27Al MAS NMR spectra as well as XRD data of the derivative before and after calcination indicate presence of both four-coordinated and six-coordinated Al in varying ratios and the total loss of crystallinity.

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The present work was conducted to study the genotypic variability of rice genotypes at the germination and seedling stages at different levels of salinity (0 M, 0.15 M, 0.2 M and 0.25 M NaCl). The results showed that increasing salinity decreased germination and seedling growth. Significant genotypic variability exists in the germination and seedling stages in response to different NaCl concentrations. Most of the genotypes showed more than 90% germination in the control, indicating good seed vigour. Two genotypes, VBR 638 (93%) and VBR 644 (84%), were selected as being tolerant to salinity at 0.2 M NaCl at the germination stage. Therefore, these could be used as source materials for genetic improvement for salinity tolerance at the germination stage. A considerable amount of genotypic variability was also found under control and saline conditions at the seedling stage with respect to the variables shoot height, root length, shoot and root dry weight. The high heritability observed for these variables offers good scope for genetic improvement for salinity tolerance both at the germination and seedling stages. The genotypes VBR 616, VBR 628, VBR 645, VBR 640, VBR 611, VBR 620, VBR 612, VBR 618, VBR 644, VBR 629, VBR 625 and VBR 630 were selected as being tolerant to salinity at the seedling stage.

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Abstract  

This paper reports the effect of the variation of citrate to nitrate ratio on the thermal decomposition characteristics of alumina precursor and the properties of nanocrystalline alumina synthesized using this auto-ignition process. The technique involves the auto-ignition of a citrate-nitrate gel occurring between Al(NO3)3 and citric acid to yield an ash powder that upon calcination at 1373 K produced α-alumina. The auto-ignition was restricted to a particular range of citrate to nitrate ratio in the gel. The resulting powder exhibited large surface area (40–50 m2 gm−1) and fine crystallite size. It was established from various characterization techniques that the alumina powder prepared with a C/N ratio of 0.3 has got the optimum powder characteristics compared to the rest of the batches, thus establishing the importance of maintaining a stoichiometric or near stoichiometric C/N ratio. The process has a higher degree of reproducibility and a good potential for large-scale production of alumina.

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Preparation of nanoparticles of oxides by the citrate–nitrate process

Effect of metal ions on the thermal decomposition characteristics

Journal of Thermal Analysis and Calorimetry
Authors:
S. Banerjee
,
A. Kumar
, and
P. Sujatha Devi

Abstract

This paper reports preparation of nanoparticles of oxides by the citrate–nitrate process and the effect of metal ions on the thermal decomposition characteristics of the corresponding citrate–nitrate gel precursors. In order to understand the effect of metal ions on the thermal decomposition characteristics of the precursors, we have prepared a series of single component oxides such as MO, where M = Zn, MO2, where M = Sn, Ce, Zr, and M2O3 where M = Al, Fe, Bi. In all the cases the citrate to nitrate ratio was fixed at 0.3. In order to ascertain the decomposition characteristics of the gel samples, TG/DTA studies were performed on the dried gel samples. After complete physico-chemical characterization of the precursors and the calcined products, it could be concluded that the nature of decomposition of the precursors depends largely on the nature of the metal ions. Finally, the advantages of the citrate–nitrate process such as its high degree of reproducibility, its potential for large-scale production of nano-crystalline ceramic oxide powders and its lower cost could be established based on a series of experiments and examples.

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Abstract  

Feasibility of using fixed bed column of conventional ion exchangers/sorbent and chemical precipitation based processes have been examined for the effective removal of the very low levels of 106Ru activity from NH4NO3 effluent generated during wet processing of rejected sintered depleted uranium fuel pellets. Based on the results, a simple process involving precipitation of cobalt sulphide along with ferric hydroxide was selected and further optimization of process variables was carried out. The optimized process has been found to be highly efficient in reducing 106Ru activity down to extremely low levels.

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Thermal and infrared spectral studies of the urea-orthoboric acid complex are reported. The complex is formed through the elimination of 0.5 H2O molecule. Infrared spectral data show the presence of hydrogen-bonding and the force constant calculated for the N ... HO bond is found to be 4−5×10−5 dyne cm−1, which is for the order of a single bond and indicates strong hydrogen-bonding in the complex. A tentative structure for the complex is proposed.

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Movement and abstraction of groundwater in the geological formations are dependent on the hydro-geological parameters of the aquifers. The purpose of any aquifer test is to determine the hydro-geological parameters. Among the basic parameters are the specific storage, permeability and leakage coefficients. The hydro-geological parameters are hidden in the field test data and their identification is possible using the available physically plausible models suitable for the prevailing field circumstances. In this context, a generalized theoretical solution for the effect of partial penetration superimposed over the full penetration on draw-down in a large-diameter well in artesian aquifer discharging at a constant rate has been presented for non-dimensional quantities describing the variable geometries of wells. The well-function curves are developed by varying the percentage amount of drilling and the percentage amount of casing lowered which then control to vary the percentage amount of open-hole or screened interval for the three categories: when the diameter of the cased interval in which the water level changes is greater than, equal to, and less than the diameter of the open interval. The skin effect and the effect of leakage are neglected. A comparison of results with the published works has also been presented. The present study is useful in such areas where wells are located either in harder or in collapsible loose formations; and a decision is required that, at the planning, construction, or development stage, as to what extent the amount of drilling be reduced, and/or an additional amount of casing be lowered within the aquifer. Also this reduces the cost of well construction and development in a specific situation.

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