Mössbauer spectroscopy of green shale from banded iron formation

A green shale from the Precambrian banded iron formation of the Bonai Range, Eastern India, is examined by transmission Mössbauer spectroscopy. The constituent phases are identified to be chlorite, siderite and magnetite. The fractional resonance area of each constituent is computed and the ferrous-ferric ratio determined. The variation of this ratio over the sample is examined. Intensity of the magnetite lines reveals that deviation from stoichiometry is negligible. The observations suggest a transition within short range from silicate-rich facies to carbonate-oxide-rich facies in the studied section.     

Freeze-coating on a continuous moving sheet and on an axially moving cylinder

This paper considers one-dimensional heat transfer model for the freeze-coating of a polymeric substance on a continuously moving sheet and on an axially moving cylinder. Analytical expressions are obtained for the freeze-coat thickness; also presented the solutions for an upper bound on the thickness of the frozenlayer using thermodynamic equilibrium conditions. Effect of Stefan number on freeze-coat thickness is briefly discussed and also the application of the present results with an example.     

Kinetics and mechanism of the oxidation of glycine by N-bromosuccinimide

A systematic kinetic study on the oxidation of glycine by N-bromosuccinimide (NBS) in presence of mercuric acetate in acetic acid—water media has been made. Near first order dependence inNBS and glycine and near inverse first order dependence in hydrogen ion concentrations have been observed. A negligible ionic strength effect and a positive dielectric effect have been observed. Various rate parameters have been computed and hydrocyanic acid identified as the end product. On the basis of the kinetic data, a mechanism of the reaction has been proposed.With 3 Figures     

A hard sphere model of chemical reaction in condensed media

We use the methods of hard sphere kinetic theory, projection operators and multiple time scale analysis to derive a formalism of chemical reactions in condensed media. Enskog type rates are found to be capable of explaining the primary salt and solvent effects but are valid for the special case of the slow reaction limit where the threshold energy does not depend on the proximity of third bodies and the smooth tail and mass do not change upon reaction. Rigorous diffusion limited laws may also be derived.     

Empirical model for electron impact ionization cross sections of neutral atoms

A simple empirical formula is proposed for the rapid calculation of electron impact total ionization cross sections both for the open- and closed-shell neutral atoms considered in the range 1≤ Z≤92 and the incident electron energies from threshold to about 10⁴ eV. The results of the present analysis are compared with the available experimental and theoretical data. The proposed model provides a fast method for calculating fairly accurate electron impact total ionization cross sections of atoms. This model may be a prudent choice, for the practitioners in the field of applied sciences e.g. in plasma modeling, due to its simple inherent structure.