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The interactions between surfactant and water were studied thermoanalytically focusing on the lyotropic liquid crystalline and microemulsion region in four ternary systems containing Cremophor EL and Cremophor RH40 as surfactants, neutral oil and isopropyl myristate as oily components. Subzero temperature DSC (SZT-DSC) measurements were carried out to determine the quantity of the bound water forming a hydration layer in surfactant microstructures, and the amount of free water, which has physico-chemical properties not much different from those of pure water. The variation of the surfactant:bound water ratio in the function of water concentration was also investigated. Phase changes detected by the SZT-DSC measurements were confirmed by polarization-microscopic and rheological investigations.

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The migration of HTO from a point source was studied in the soil of the storage of radioactive waste at horizontal distances of 10 to 40 cm from the source between 2 and 4 m depths at 5 different rainfalls, up to 7641/m2. The water movement changed from 0.17 cm/l (at 10 cm) to 0.28 cm/l (at 40 cm distance) when 186 1 was irrigated, while at 764 1 rainfall it was found to be 0.11 cm/l at every distance. The estimated parameters of a three-dimensional migration model constructed to characterize HTO movement revealed that the HTO distribution migrates downwards in a small, about 1 m thick layer with an initial rate of 0.17 cm/l to slow down to about 0.05 cm/l after 50 years. The distribution is spreading horizontally with a constant rate of about 0.08 cm/l.

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Journal of Thermal Analysis and Calorimetry
Anita Kovács
I. Csóka
Magdolna Kónya
E. Csányi
A. Fehér
, and
I. Erős

The properties of the inner and the external aqueous phases, were studied in w/o/w multiple emulsions with light microscopic image analysis and differential scanning calorimetry (DSC). The importance of multiple emulsions lies in the presence of these aqueous phases, making them available for sustained, controlled drug delivery systems. Differentiation of these two aqueous phases, studying the effect of manufacturing technology on droplet structure, quantitative determination of phase volumes and any changes occurring during storage are essential when planning w/o/w emulsions. The present study uses microscopic observations combined with DSC measurements in order to identify the formed structure, at developmental stage in case of different components, preparation methods, and stirring rates. These tools are beneficial during manufacturing as in process controls, or to ensure product quality.

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