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  • Author or Editor: T. Asano x
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Abstract  

Miscibility and dehydration of poly(2-hydroxyethyl methacrylate) and poly(methacrylic acid) (PHEMA/PMAA) blends were investigated by temperature modulated DSC (TMDSC), TG and solid-state 13C NMR methods. TMDSC spectra and 1H spin-relaxation times showed that the blends are homogeneous on a scale of 5-10 nm for all compositions. From TG and 13C NMR, we elucidated that the mass loss of the blends at 300C is ascribed to the dehydration between the hydroxyl group of PHEMA and the carboxyl group of PMAA.

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Abstract  

The effects of incorporating tritiated water into a 14C-sampling system in sample preparation and 14C activity measurement by liquid scintillation counting were investigated. Experiments derived the limit of water content in the prepared sample, and also demonstrated that 14C activity can be determined without any interference from 3H contamination for a clear-sample solution. The results enabled us to estimate the permissible relative humidity of air required for accomplishing sample preparation and 14C activity measurement. These showed that for sampling of air with less than the permissible relative humidity, total 14C activity in airborne effluent can be evaluated accurately without dehumidification of air.

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Abstract  

The extraction equilibria were investigated of the thenoyltrifluoroacetone (TTA) chelate of uranyl ion between aqueous perchlorate medium and thirteen organic solvents. The extracted species was shown to be UO2A2. The solubility parameter of the chelate was estimated from the partition data and it was confirmed that the relationship lgPM=n lgPHA+const. holds for the present system. When the extraction constant (Kex) is considered in relation to the distribution coefficients, theKex values are expected to be constant under certain conditions for all of the solvents; the lgKex values were found to be constant (lgKex=−2.85±0.17).

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Summary  

To establish a practical method for monitoring 129I concentration in airborne release from the Tokai reprocessing plant, the 129I collecting performance of sampling media used was tested by in situ experiments. The results indicated that the combined use of an activated charcoal-impregnated filter paper and an activated charcoal cartridge gives a collection efficiency of more than 90% for a one-week sampling of real airborne effluent, at sampling flow rates of 40.6-75.0 l. min-1. The sampling and measurement conditions suitable for a routine-base monitoring are demonstrated.

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Abstract  

A method using a system with two sampling units was proposed to determine the chemical forms of tritium (3H) released into the atmosphere from the Tokai Reprocessing Plant (TRP). The main advantage of the method is that no carrier gas is required for sampling in the case when air to be sampled has high specific activity with tritiated hydrogen (HT). Investigations using this method showed that 19.1–28.3% of total airborne 3H was released as HT from the TRP during reprocessing operation. No clear relation was found between the ratios of HT release and the types of spent fuel reprocessed.

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