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  • Author or Editor: G. Fóti x
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Abstract  

For the selective removal of the matrix activity (24Na,32P and42K) in the neutron activation analysis of biomedical samples the inorganic separators “hydrated antimony pentoxide”, zirconium phosphate, and titanium phosphate were prepared. The sorption parameters of the samples were determined via elution chromatography techniques, with appropriate tracers. The basic principles of the sorption processes were investigated, and the experimental conditions were optimized. These inorganic separators were then applied, combined with a distillation procedure and an ion-exchange separation, for the determination of the following trace elements in animal blood samples: Mn, Co, Cu, Fe and Zn.

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Abstract  

A control system for monitoring the radioactive concentration in aqueous wastes of nuclear installations was elaborated. The mobile station developed for in situ control enables simultaneous measurement of gamma radiation in the energy range of 0.15–2.0 MeV and that of beta radiation in the energy range of 0.3–2.0 MeV by means of a combined scintillation detector. Disturbing effects of accompanying and secundary radiations on the determination of the counting efficiency vs. radiation energy functions used in calculation of the radioactive concentration limits as well as some experiences during a long time of operation of the system have been discussed.

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Abstract  

The previously found strong dependence of the polymerization enthalpy on the reaction temperature has been rationalized. The temperature dependence is to be ascribed to the existence of a ‘ceiling temperature’ for the polymerization process of the pyrrole monomer. The determined ceiling temperature has beenT≊350 K when FeCl3 was used as the oxidizing agent in CH3CN solution. The existence of a ceiling temperature together with its already determined exoenthalpic nature allows to classify the polymerization reaction as an exoentropic one. From the dependence of the yield of insoluble polymer on the reaction temperature, the trend of the relative mean numeral molecular massM n for the different obtained polymers has been determined. Measurements of electrical conductivity on pressed pellets of the different polymers allowed to establish a correlation between theM n value and the conductivities The dependence of the conductivity on the exposition time to the air allowed to do some essays on the aging behaviour of the obtained polypyrrole. By making some assumptions, an absolute calorimetric determination of the value ofM n of polypyrrole was tempted together with that of the related poly-N-vinilpyrrole.

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