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Abstract  

The thermal decomposition using TG, DTG and DTA, of seven complexes of the types Bu2SnL(I) and Bu2SnL(II) (where H2L(I)=Schiff base derived from acetylacetone and glycine [H2L-1(I)] or L-leucine [H2L-4(I)] or methionine [H2L-5(I)] or phenylglycine [H2L-6(I)]; H2L(II)=Schiff base derived from o-hydroxynaphthaldehyde and β-alanine [H2L-2(II)] or DL-valine [H2L-3(II)] or L-leucine [H2L-4(II)] is shown to fall into one of two categories, viz, (1) Bu2SnL(I) complexes that decompose without melting to give SnO as the final tin containing product, (2) Bu2SnL(II) complexes that melt and then decompose to give SnO. Mathematical analysis of TG data using Coats-Redfern equation, Horowitz-Metzger equation, and Fuoss method shows that the first order kinetics is applicable in all the complexes except Bu2SnL-2(II). Kinetic parameters such as the energy and entropy of activation and pre-exponential factor are reported.

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Abstract  

The two step oxidation of UO2+x and reduction of U3O8 powders observed during Differential Thermal Analysis (DTA) has been exploited to determine their Specific Surface Areas (SSAs). The results obtained by this method have been compared with the Braunauer, Emmett and Teller (BET) method and are found to be in good agreement in the SSA range of 2–4 m2/gm in the case of UO2+x obtained from ADU route and 4–8 m2/gm in the case of AUC route. A precision of ±0.1 m2/gm is obtained. The maximum temperature of oxidation and reduction of these oxides are dependent upon their preparative routes such as Ammonium Diuranate (ADU) and Ammonium Uranyl Carbonate (AUC).

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Abstract  

A radiochemical displacement method was utilized for the determination of traces of mercury in water taking advantage of its ability to displace cobalt from cobalt(III) diethyldithiocarbamate tagged with60Co. The method is found to be applicable in the concentration range of 50–200 g/ml mercury. The interfernces from various cations like Fe(III), Co(II), Cu(II), Pb(II) and Ag(I) ions were studied.

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Abstract  

Energy dispersive X-Ray fluorescence (EDXRFS) method is developed and standardized for the determination of uranium on routine basis in various process stream solutions, covering a vide range of concentrations from 0.1 to 400 g L−1, from an Uranium Extraction Plant at Nuclear Fuel Complex. The method has been applied to aqueous stream samples. Except for dilution, no much sample preparation was involved in the analysis and accordingly the experimental parameters were optimized. The calibration curve in the range of 0.1–10 g L−1 of U was drawn manually using synthetic standard solutions prepared from U3O8 powder and Lα (13.61 keV) line of uranium was used for the measurements. The results from EDXRFS method are compared with other methods and are found to be in good agreement. The EDXRFS measurements carried over a range of 0.1–350 g L−1 of uranium have shown a RSD of ±1–5%. Also, the limitations of reported methods in literature and the advantages of present method are highlighted in the paper.

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Inheritance of male sterility and fertility restoration of the A 1 system of cytoplasmic-nuclear male sterility in pearl millet was investigated using 12 crosses among three diverse male sterile lines (A-lines) and four diverse restorers (R-lines). Individual plants from R- lines were used to make crosses on A-lines. The segregation pattern of male sterile (S) and male fertile (F) plants observed in F 2 and BC 1 in two seasons at ICRISAT, Patancheru was suggestive more likely of a single-gene control of male sterility and fertility restoration. However, a 3-gene model of male sterility/fertility restoration where dominant alleles at any two of the three duplicate complimentary loci will lead to male fertility could not be ruled out, nor could be ruled out a 2-gene control with duplicate interaction. There was indication of variability even within a highly inbred R-line for fertility restoration gene(s). Depending on the genetic constitution of the R-lines at these loci, even the 3-gene model can lead to single-gene segregation ratios as observed in most of the F 2s and backcrosses, and 2-gene ratios as observed in a few F 2s and backcrosses. The deviations from these expected ratios in some of the crosses influenced by modifiers and environmental conditions generally resulted from the excess of fertile plants in the rainy season or excess of sterile plants in the dry season, the more so in crosses involving an A-line which has been reported to be relatively more unstable for male sterility.

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Selection on the basis of grain yield per se for improved performance under excessive moisture stress has often been misleading and considered inefficient. We assessed the importance of secondary traits of adaptive value under waterlogging stress. During the 2000–2004 summer-rainy seasons twelve trials were conducted and a total of 436 tropical/subtropical inbred lines (S 4 –S n ) were evaluated under excessive soil moisture stress. Excessive moisture treatment was applied at V 6–7 growth stage by flooding the experimental plots continuously for seven days. Different phenological and physiological parameters were recorded before, during and either immediately or 1–2 weeks after exposure to stress. Excessive moisture conditions significantly affected all the morphological and physiological traits studied. However, there was significant genetic variability for various traits, especially for root porosity and brace root development that were induced under excessive moisture. Across the trials, significant genetic correlations (p<0.01) was obtained between grain yield and different secondary traits, including ears per plant, root porosity, brace root fresh weight, number of nodes with brace roots and anthesis silking interval. Broad-sense heritability decreased under excessive moisture stress conditions for most of the traits; however, it increased significantly for root porosity, nodal root development and ears per plant. Our findings suggest that consideration of these second-ary traits during selection of maize germplasm for excessive moisture tolerance can improve selection efficiency and genetic gains.

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Abstract  

Rubidium uranium trisulphate [Rb2U(SO4)3] was prepared as a high purity compound of uranium in different lots of 250 g each. The compound was characterised and evaluated by chemical, atomic spectrosopic, infrared, X-ray diffraction and thermogravimetric methods for its use as a chemical assay standard for uranium. The compound is stoichiometric, pure, homogeneous and stable in atmospheric conditions. The solubility studies showed that Rb2U(SO4)3 is easily soluble in mineral acids. An experiment based on Randomised Block Design was carried out to assign a value to the uranium content in Rb2U(SO4)3 from the statistically analysed chemical data. The assigned value of [34.167±0.042]% to the uranium content is in close agreement with the theoretical value of 34.152%. Based on these studies, Rb2U(SO4)3 is recommended as a chemical assay standard for uranium.

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Abstract  

This paper describes a method of calculation of saturated concentration of uranium in TBP, the organic phase obtained in a solvent extraction process in a uranium extraction plant. The calculation utilizes only the other available routine parameter such as %TBP in the respective lean solvent.

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Cereal Research Communications
Authors: S. Gupta, R. Yadav, K.B. Gaikwad, A. Arora, A. Kumar, A. Kushwah, and N.K. Bainsla

Physiological breeding complementing the conventional approach is increasingly being explored in wheat in view of stagnating annual genetic yield gain. Designing improved plant types required knowledge about physiological traits associated with yield gain in the past. Fourteen wheat varieties including 12 historically important and popular (mega) wheat cultivars and two recently registered varieties were observed for various physiological traits for two years. Both breeding period and genotypes within breeding period accounted for significant differences for most of the physiological traits. Regression analysis indicated curvilinear trend for leaf area index (LAI), flag leaf area, and root length and root weight. Near perfect leaf area index (LAI 5.94) with semi-erect leaves and higher flag leaf area was observed in all time mega variety HD 2967 indicated the importance of plant architecture and crop canopy in yield maximization. Linear declining trend was observed for coleoptile length, number of stomata per cm2 and flag leaf length. Increasing trend for total chlorophyll content and normalized difference for vegetative indices (NDVI) at both vegetative and flowering stage indicated the importance of leaf greenness in yield improvement. Root length has continuously declined except for the latest released varieties, however no such trend was observed for root weight. We propose that grain yield stabilization at still higher level can be achieved by increasing photosynthetic capacity, optimizing the crop canopy slightly less than the optimum, and better partitioning to grain yield through directed physiological based breeding.

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Abstract

Two aluminate spinel materials (ZnAl2O4 and NiAl2O4) were synthesized by the citrate precursor method. The citrate precursors consisting of coprecipitated citrates of Zn2+ or Ni2+ and aluminum were first subjected to thermal analysis (TG-DSC) for determining the optimum temperature for annealing. Two step decomposition was observed incorporating dehydration and formation of the aluminate. The second step gives an endo peak (−2937 J/g) at 356 °C in the DSC curve of the coprecipitated nickel(II) citrate–aluminum citrate gel in O2 atmosphere. Kinetic/mechanistic analysis of the TG data has also been carried out and values of E a, ΔS #, ΔG #, and A were approximated. On the basis of the findings, 450 °C has been chosen for annealing of the gels. Annealing has also been done at 650 °C for 1 h in muffle furnace in an attempt to obtain nanometric particles of aluminates (MAl2O4) {M = Ni, Zn} and to find out their magnetic properties which could render them useful for chemical sensing applications, etc. The TG-DSC curves of various powders which were obtained on annealing at the two temperatures did exhibit thermal instability when carried out in N2 atmosphere. NiAl2O4 and ZnAl2O4 spinels (particle size 17 and 34 nm, respectively) are obtained in pure crystalline phase at 650 °C. ZnAl2O4 prepared this way shows coercivity values of 470 and 58.37 G and NiAl2O4, 107 and 23.24 G when annealed at 450 and 650 °C, respectively. ZnAl2O4 prepared by a polymer precursor method and annealed at 1000 °C, has earlier been reported to have coercivity value of 469 G. Thus, the citrate precursor method is good for the synthesis of ZnAl2O4, producing single phase nanocrystalline powder of high quality and crystallinity. The value of magnetization was found to be small in the present case for the NiAl2O4 spinel obtained at 450 °C.

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