In the Czech Republic, river bottom sediments have been systematically monitored since 1999. In the paper, their radioactive contamination due to uranium mining and milling is assessed. The sediments samples were analyzed by gamma spectrometry. Especially the radium-226 and radium-228 activities were further evaluated.The highest values of the radium-226 activities were found at river profiles where the uranium industry impact was obvious. It turned out that the radium-226 and radium-228 activities ratio is more convenient to assess the level of radium-226 contamination than only the radium-226 activity itself. Based on this hypothesis, the sediment classification scheme for uranium industry contamination was suggested. The natural background activities of radium-226 and radium-228 in the Czech Republic were also evaluated. The case of radium-226 contamination due to the uranium industry was studied in details at the Ploucˇnice River.
ZUSAMMENFASSUNG:Fur die Bestimmung der Grenzviskositatszahl [q] von nitroso-oxydierter Cellulose in verdunnter Losung wurde die EWNN Methode (alkalische Ldsung eines EisenWeinsaure-Natrium-Komplexes) angewandt. Die bisher bekannten Berechnungsmethoden von [q]
SUMMARY:To determine the limiting viscosity number [q] of nitrous oxidized cellulose in diluted solution, the iron tartrate complex method (FeTNa) was used. Existing methods of the [ql-values calculation using polynomials for various types of polymers and various solvent measuring systems and also the polynomial for pure cellulose have been shown to be inapplicable. Therefore, an empirical calculation formula in explicit form
Die stufenweise Oximierung bei 20, 23, 25, 28, 30 und 35°C ermöglichte die qualitative und quantitative Trennung von sechs verschiedenen Aldehydgruppen in Oxycellulose. Für die Berechnung des Gehaltes bn der n‐ten Aldehydgruppe bei einer bestimmten Oximierungstemperatur wurde eine modifizierte Berechnungsmethode nach einer verbesserten Gleichung angewandt. Das vorgeschlagene Verfahren ermöglichte die Charakterisierung der chemischen Strukturen von sechs verschiedenen Aldehydgruppen in Oxycellulosemakromolekülen. Es wurden lineare Abhängigkeiten zwischen den Gehalten an diesen Aldehydgruppen sowie den Aldehydsummenwerten und DP‐Werten bei logarithmischer Darstellung gefunden, die eine indirekte und schnelle Aldehydbestimmung in Oxycellulosen über den DP‐Wert ermöglichte. Für die indirekte Bestimmung der Aldehydgruppen über den DP‐Wert wurde ein Computerprogramm ausgearbeitet.
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