Direct determination of uranium in sintered deeply depleted uranium oxide pellets by wavelength dispersive X-ray fluorescence spectrometry

This paper presents studies on direct non-destructive determination of uranium in sintered deeply depleted (DD) uranium oxide (UO₂) pellets by wavelength dispersive X-ray fluorescence (WDXRF) spectrometry. A special collet was designed and fabricated for holding the sintered DDUO₂ pellets for direct analysis, thus avoiding the sample preparation steps. The samples were analyzed using a calibration plot obtained from WDXRF spectra of matrix matched calibration standards. The WDXRF determined uranium values were found to be in very close agreement with titrimetric values and has reproducibility better than 0.05% (RSD, 1 s, n = 10) for the sintered DDUO₂ pellets having U: 86.81–88.04 wt%.

     

A comparative study of RKRV and reduced potential curves of the ground states of alkaline-earths chlorides

In light of the recording and analyzing of high resolution FT spectrum of MgCl molecule, a comparative study of the RKRV and RP curves of the ground states of alkaline earth chloride viz. BeCl, MgCl, CaCl, SrCl and BaCl have been made using latest molecular constants. The H-H and extended Rydberg potential functions compete each other and have excellent agreement with RKRV curves for all the molecules. Because of the use of improved constants the Potential Energy curves in present study are better as compared to earlier workers.     

Determination of rotational temperature of AlO from the B2Σ+-X2Σ+ system

AlO molecule was excited in a DC arc in air running between two aluminium electrodes. Rotational structure of the (0,0) band of the B²Σ⁺-X²Σ⁺ system of AlO molecule was photographed in the first order of a 10.6 m concave grating spectrograph. Intensity distribution amongst the well-resolved rotational lines of R₁ and R₂ branches was recorded and the average rotational temperature calculated from these has been determined as 2880 ± 100 K.     

Fractal pattern growth simulation in electrodeposition and study of the shifting of center of mass

We presented simulation of fractal pattern in electrodeposition (Diffusion limited aggregation) using concept of off lattice walk.It is seen that the growth patterns are based on a parameter called ‘bias’. This parameter ‘bias’ controls the growth of patterns similar to that of electric field in electrodeposition technique. In present study the fractal patterns are grown for different values of ‘bias’. Dendritic patterns grown at lower value of ‘bias’ comprises open structure and show limited branching. As the bias is increased the growth tends to be dense and show more crowded branching. Box counting was implemented to calculate fractal dimension. The structural and textural complexities and are compared with the experimental observations.It was also noted that in the evolution of DLA patterns, the center of mass of the growth is shifted slightly. We tracked the position of the center of mass of simulated electro deposits under different electric field conditions. The center of mass exhibit random walk like patterns and it wanders around the origin or the starting point of the growth.     

Low-temperature magnetisation study on manganese(III) porphyrins

Average magnetisation between 2 and 20 K and 10 and 50 kOe of two typical high-spin manganese(III) porphyrins, namely TPPMnCI and TPPMnCl(py), is reported for the first time. The results have been analysed in terms of spin hamiltonian formalism including both the crystal field and magnetic exchange.     

Polymer nanocomposite membranes and their application for flow catalysis and photocatalytic degradation of organic pollutants

The modern world essentially needs a chemical industry that can operate with reduced production costs, and produce high-quality products with low environmental impact. The polymer nanocomposite-based flow catalytic membrane reactor where the reaction and separation can be amalgamated in one unit is considered as one of the new alternative solutions to solve these problems. In this review, we have discussed state-of-the-art flow-through catalytic reactors based on polymer nanocomposite membranes. The unique advantages of flow catalysis include uninterrupted operation, good recyclability, and reaction product without contamination that leads to simple purification. Various catalytic model reactions such as coupling, hydrogenation, esterification in the flow system are presented. We have also presented an overview of methods adopted for preparing such nanocomposite membranes. In the last section, a discussion has been made on the recent advances on polymer-based nanocomposite membranes for the degradation and separation of organic pollutants.     

On the potential energy curves of LaO molecule

Turning points for several electronic states of LaO molecule are calculated using the Rapid method by Morse function, and compared with those obtained by RKR method. The electronegativity potential function and RKR potential functions are compared for the ground state of the molecule and an estimate of dissociation energy of LaO molecule in the ground state is reported.     

Estimation of rotational and vibrational constants for diatomic molecules using Mattera's potential function

Summary The potential function suggested by Mattera, Salvo, Terreni and Tommasini is investigated further and the expressions for rotational constant α_e and anharmonicity constantw _e x _e are obtained. The α_e andw _e x _e values of twentyseven diatomic molecules are calculated using those expressions and they are compared with their experimental values.     

High-resolution F T spectrum of A2Πr-X2Σ+ band system of MgCl

The emission spectrum of the A ² Π _r -X ² Σ ⁺ band system of MgCl molecule (360–380 nm) has been recorded on BOMEM DA8 Fourier transform spectrometer at an apodized resolution of 0.035 cm⁻¹. The spectra have been excited under flowing conditions in a demountable stainless steel hollow cathode lamp (400 V, 250 mA) containing anhydrous MgCl₂ and Ar. The resulting spectra are very intense and the 0-0, 1-1, 1-0 bands of A ² Π _1/2-X ² Σ ⁺ sub-transition and the 0-0 band of A ² Π _3/2-X ² Σ ⁺ sub-transition have been rotationally analyzed. Improved molecular constants have been derived using a least-squares fit program in which optical data of earlier analyzed 0-1 and 0-2 bands (A ² Π _1/2-X ² Σ ⁺) was also included. The Λ-doubling constants in the v′ = 0, 1 levels of the A ² Π _1/2 sub-state are as expected, i.e. p ₁ > p ₀, where as it is found that the spin-doubling constants of the v″ = 0, 1 and 2 levels of the ground state X ² Σ ⁺, decrease with the increase in v, i.e. γ ₀ > γ ₁ > γ ₂. This is indicative of the presence of some nearby state, influencing the spin-doubling.