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The reduction and the smoothened amplitudes of the chloride concentrations since 2000 have resulted in a gradual positive development of the aquatic fauna in the River Werra. In the salinized section of the river increasing species numbers have been determined along the salinity gradient, which shows maximum chloride concentrations of about 2500 mg/l, maximum potash concentrations at approximately 200 mg/l, and magnesia concentrations peaked at 320 mg/l. As an immediate consequence of the reduction in salt concentration the immigration of various caddis fly species into the lower River Werra was observed. The Number of taxa per sample rose from 5 to more than 30 in the lower Werra region. Changes in species-richness could be seen more frequently in river sections where chloride concentrations fluctuated around 1500 mg/l. 相似文献
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This paper deals with the dissolution of magnesia in aqueous carbon dioxide, in the absence and presence of ultrasound. The particle size, reaction temperature and solid / liquid ratio were chosen parameters. The reaction was homogeneous first-order reaction model according to kinetic data and the activation energy was found to be 17.5 kJ/mol in both cases. The effect of ultrasound is on the pre-exponential factor A in the Arrhenius equation. An empirical relation was also given, which relates the rate constant to ultrasound power. 相似文献
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