CHEMICAL KINETICS OF WEATHERING IN YOUNG ANDISOLS FROM NORTHEASTERN JAPAN USING SOIL AGE NORMALIZED TO 10°C

Soil Science ◽  
1993 ◽  
Vol 155 (1) ◽  
pp. 53-60 ◽  
Author(s):  
SADAO SHOJI ◽  
MASAMI NANZYO ◽  
YASUHITO SHIRATO ◽  
TOYOAKI ITO
Keyword(s):  
Chemical Kinetics ◽  
Northeastern Japan ◽  
Soil Age ◽  
Kinetics Of

Vulcanization of Elastomers. 23. The Chemical Kinetics of Vulcanization Reactions and The Physical Properties of The Vulcanizates. I

1960 ◽  
Vol 33 (2) ◽  
pp. 335-341
Author(s):  
Walter Scheele ◽  
Karl-Heinz Hillmer
Keyword(s):  
Activation Energy ◽  
Physical Properties ◽  
Chemical Kinetics ◽  
Kcal Mole ◽  
First Order ◽  
Equilibrium Swelling ◽  
Kinetics Of ◽  
Kinetics Of Vulcanization ◽  
Limiting Value ◽  
Good Agreement

Abstract As a complement to earlier investigations, and in order to examine more closely the connection between the chemical kinetics and the changes with vulcanization time of the physical properties in the case of vulcanization reactions, we used thiuram vulcanizations as an example, and concerned ourselves with the dependence of stress values (moduli) at different degrees of elongation and different vulcanization temperatures. We found: 1. Stress values attain a limiting value, dependent on the degree of elongation, but independent of the vulcanization temperature at constant elongation. 2. The rise in stress values with the vulcanization time is characterized by an initial delay, which, however, is practically nonexistent at higher temperatures. 3. The kinetics of the increase in stress values with vulcanization time are both qualitatively and quantitatively in accord with the dependence of the reciprocal equilibrium swelling on the vulcanization time; both processes, after a retardation, go according to the first order law and at the same rate. 4. From the temperature dependence of the rate constants of reciprocal equilibrium swelling, as well as of the increase in stress, an activation energy of 22 kcal/mole can be calculated, in good agreement with the activation energy of dithiocarbamate formation in thiuram vulcanizations.

Gas phase chemical kinetics of sodium in the upper atmosphere

Nature ◽  
1976 ◽  
Vol 263 (5577) ◽  
pp. 488-490 ◽  
Author(s):  
C. E. KOLB ◽  
J. B. ELGIN
Keyword(s):  
Gas Phase ◽  
Chemical Kinetics ◽  
Upper Atmosphere ◽  
Kinetics Of ◽  
Phase Chemical
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