[en] Quantitative evaluation of radiographic image features is possible by image analysis systems provided image quality is suitably enhanced. Tolerance of the alloys for the same volume fraction of defects is different, which necessitates preparation of defect-property correlation data for various casting alloys to enable quality control authorities fix a realistic standard of acceptance and designers to provide a higher or lower safety margin depending upon the state of manufacturing technology. It is possible to grade ASTM reference radiographs on a quantitative basis which will provide a more meaningful standard of comparison

[en] A systematic study of the molecular and crystalline structures of the mesogenic compounds is of considerable interest in order to interpret a number of basic physical properties of liquid crystals. In view of this an a priori determination of the molecular packings have been made for the liquid crystalline materials p-p-ethoxyphenylazo phenyl heptanoate and undecylenate based on the earlier results of detailed molecular structure data for the similar molecules, p-p-ethoxyphenylazo phenyl valerate and hexanoate and the model approach of Kitaigorodsky. The estimated packing coefficients correlate well with thermal stabilities in the homologous series

[en] An attempt was made to explain the diffuse streaks or tails present in the X-ray diffraction photographs of liquid crystalline materials. Due to anisotropy of thermal motion, the placement of the atoms in the linear molecules of the mesogenic materials no longer corresponds to an ideal lattice at each instant. The scattering by such anisotropically vibrating molecules which can be treated as diffraction by standing waves, essentially alters the diffraction condition, which is the reason for certain diffusion spots to pick up diffuse tails or streaks depending upon the anisotropy of vibration of the molecules. (author)

No abstract available

[en] Na₂ZnP₂O₇·HCl single crystals were synthesised by hydrothermal technique and characterised by X-ray diffraction method. The compound crystallises in tetragonal system with space group P4₁2₁2 and cell parameters a=7.687(5) A, c=20.529(1) A, Z=8, having tunnel type of cavities in the structure. DTA study indicates that this compound is thermally fairly stable

No abstract available

[en] 15 UD pelletron accelerator at Nuclear Science Centre, New Delhi, uses two types of stripper at high voltage terminal-those are gas stripper and foil stripper. Gas stripper is generally used for heavy ions and foil stripper for light ions. Stripping efficiency depends upon the health of stripper foil used. It is very important to ensure the condition of stripper foil in use is good for smooth operation of accelerator

[en] Short communication. 5 refs., 1 fig

[en] Potential alpha energy exposure (PAEE) due to radon and its progenies has been measured in 17 dwellings in the city of Allahabad. The measurements were carried out by a passive time integrated method, using LR-115 (Type II) detector in bare mode. The geometric mean of potential alpha energy exposure in dwellings of Allahabad has been estimated to be 9.41.6 mWL and the results obtained are discussed under the light of exposure limits set by International Commission on Radiological Protection (ICRP). (author). 7 refs., 1 fig

[en] Constraining parameters of a theoretical model from observational data is an important exercise in cosmology. There are many theoretically motivated models, which demand greater number of cosmological parameters than the standard model of cosmology uses, and make the problem of parameter estimation challenging. It is a common practice to employ Bayesian formalism for parameter estimation for which, in general, likelihood surface is probed. For the standard cosmological model with six parameters, likelihood surface is quite smooth and does not have local maxima, and sampling based methods like Markov Chain Monte Carlo (MCMC) method are quite successful. However, when there are a large number of parameters or the likelihood surface is not smooth, other methods may be more effective. In this paper, we have demonstrated application of another method inspired from artificial intelligence, called Particle Swarm Optimization (PSO) for estimating cosmological parameters from Cosmic Microwave Background (CMB) data taken from the WMAP satellite