Crystalloluminescence and temporary mechanoluminescence of As2O3 crystals

Crystalloluminescence and temporary mechanoluminescence of As₂O₃ crystals are investigated. The crystalloluminescence spectra are similar to the photoluminescence and mechanoluminescence (of fresh crystals, in CO₂ atmosphere) spectra. The mechanoluminescence spectra of freshly grown crystals taken in air consist of the superposition of the photoluminescence and nitrogen emissions. The mechanoluminescence spectra of old crystals of As₂O₃ consist of only the nitrogen emission. The total number of crystalloluminescence flashes is linearly related to the total mass of the crystals grown. The mechanoluminescence intensity increases with the mass of the crystals. The mechanoluminescence intensity decreases with the age of the crystals and the rate of decrease increases with increasing temperature of the crystals. Different possibilities of crystalloluminescence and mechanoluminescence excitations in As₂O₃ crystals are explored and it is concluded that crystalloluminescence and mechanoluminescence are of different origins.     

The proton strength distribution of the 1g 9/2 state of41Sc

The distribution of the 1g _9/2 proton state of the⁴¹Sc has been obtained within the framework of the coreparticle coupling model scheme. The theoretical distribution pattern of this high-spin proton orbital has been compared with the recent high resolution experimental works performed on the⁴⁰Ca target nucleus. The results obtained in the work has also been compared with the other existing theoretical results.     

Internal electrolysis for the separation of ions: Part I.Separation and determination of silver,bismuth, copper and cadmium

The technique of internal electrolysis is recommended for the separation of ions. By proper control of the conditions, i.e. by adjustment of pH and by addition of complexing agents, it is possible to separate silver, bismuth, copper and cadmium from each other and from many other ions.     

A short synthesis of 4-aryioxymethyl-δ3-chromenes and 3-(β-aryloxy)ethylbenzofurans

A direct and short route to the synthesis of 4-aryloxymethyl-δ³ -chromenes and 3-(β-aryloxy)-ethylbenzofurans is described. Hydration of I,4-diaryloxy-2-butynes with mercuric oxide and sulfuric acid affords, instead of a ketone, the cyclization product of the ketone. In three of the diaryloxy-butynes studied, the corresponding aryloxyethylbenzofurans are formed. In no instance could the ketone be isolated from the hydration reaction.     

Mathematical modelling of flows in recessed wall flame holder

A finite difference procedure has been employed to predict the flow situation in a recessed wall flame holder with and without combustion. Turbulence has been modelled by an ad hoc effective viscosity law. A single step chemical reaction has been assumed in dealing with the flows involving combustion. The predicted physical parameters have been compared with the experimental results. It has been argued that with the simplifying assumptions on turbulence and chemical kinetics the numerical procedure is adequately accurate to predict the important design parameters such as flame length and blow-off velocity. However, there are significant discrepancies between the predicted and measured distribution of velocity and temperature which could be attributed mainly to the inadequate turbulence modelling.     

Connectivity constant of the kagomé lattice

From the computation of self-avoiding walks on the kagomé lattice, its connectivity constant is found to be 2·569 ± 0·008.     

Three-pion interferometry results from central Pb+Pb collisions at 158A GeV/c

Three-particle correlations have been measured for identified pi(-) from central 158A GeV Pb+Pb collisions by the WA98 experiment at CERN. A substantial contribution of the genuine three-body correlation has been found as expected for a mainly chaotic and symmetric source.