Oxidation of coals in the course of mechanical treatment

The results of a study of coal oxidation under stationary conditions and during mechanical treatment are presented. A considerable increase in the reaction rate constants of coal oxidation during mechanical treatment because of oxidative mechanical degradation was found. © 2009 Allerton Press, Inc

Oxidation of coals in the course of mechanical treatment

The results of a study of coal oxidation under stationary conditions and during mechanical treatment are presented. A considerable increase in the reaction rate constants of coal oxidation during mechanical treatment because of oxidative mechanical degradation was found. © 2009 Allerton Press, Inc

Spin-spin relaxation of aqueous clusters of Na+ and K+ as studied by O-17 NMR spectroscopy

The relaxation characteristics of the O-17 nucleus in aqueous clusters of Na+ and K+ were studied by nuclear magnetic resonance (NMR) spectroscopy. The influence of the viscosity p and pH value of the solution on the spin-spin relaxation of O-17 nucleus was investigated. In the presence of either electrolyte at concentrations from 10(5) to 4 mol/l, the spin-spin relaxation time is longer than for doubly distilled water. This suggests that the water network experiences rearrangement under the action of these cations

Spin-spin relaxation in the 17O NMR spectra of Na+ and K+ water clusters

Relaxation characteristics of Na+ and K+ water clusters were studied by 17O NMR spectroscopy. The influence of viscosity p and pH of solution was taken into account; for both electrolytes in the concentration range 10-5-4 M, spin-spin relaxation times are greater than those for pure water. For K+ clusters, maxima of the concentration dependence of 17O spin-spin relaxation time have been found

Spin-spin relaxation in the 17O NMR spectra of Na+ and K+ water clusters

Relaxation characteristics of Na+ and K+ water clusters were studied by 17O NMR spectroscopy. The influence of viscosity p and pH of solution was taken into account; for both electrolytes in the concentration range 10-5-4 M, spin-spin relaxation times are greater than those for pure water. For K+ clusters, maxima of the concentration dependence of 17O spin-spin relaxation time have been found

Kinetic parameters and activation criteria of the oxidative mechanical degradation of coals

The kinetic parameters of the oxidative mechanical degradation of various coals on treatment in various dispersers were determined. The rate constants of these reactions are the criteria of the mechanical activation of coals. Based on the experimental results, the effective temperatures of these processes were calculated. © 2010 Allerton Press, Inc

Spin-spin relaxation of aqueous clusters of Na+ and K+ as studied by O-17 NMR spectroscopy

The relaxation characteristics of the O-17 nucleus in aqueous clusters of Na+ and K+ were studied by nuclear magnetic resonance (NMR) spectroscopy. The influence of the viscosity p and pH value of the solution on the spin-spin relaxation of O-17 nucleus was investigated. In the presence of either electrolyte at concentrations from 10(5) to 4 mol/l, the spin-spin relaxation time is longer than for doubly distilled water. This suggests that the water network experiences rearrangement under the action of these cations

13C NMR spectroscopy of humic acids of different origin

The fragment composition of humic acids was studied by quantitative 13C NMR spectroscopy. A comparative analysis of the chemical composition of humic acids extracted from organic matter of different origin was performed. A number of structural parameters determined from the 13C NMR spectra was proposed for the classification of humic acids by origin. © 2003 by MAIK "Nauka /Interperiodica" (Russia)

Kinetic parameters and activation criteria of the oxidative mechanical degradation of coals

The kinetic parameters of the oxidative mechanical degradation of various coals on treatment in various dispersers were determined. The rate constants of these reactions are the criteria of the mechanical activation of coals. Based on the experimental results, the effective temperatures of these processes were calculated. © 2010 Allerton Press, Inc

C-13 NMR spectroscopy of humic acids of different origin

The fragment composition of humic acids was studied by quantitative C-13 NMR spectroscopy. A comparative analysis of the chemical composition of humic acids extracted from organic matter of different origin was performed. A number of structural parameters determined from the C-13 NMR spectra was proposed for the classification of humic acids by origin