Background concentrated emulsions

We hope that we have proved with ttiis short review that acoustics and electroacoustics can be extremely helpful in characterizing particle size, zeta potential, and some other properties of concentrated emulsions, microemulsions, and latex systems. Bottimefliods are commercially available already. There are still some problems with the theoretical background for electro-acoustics, but analysis of the literature shows gradual improvement in this field. 

The electrostatic repulsion between dispersed particles can be diminished by increasing the concentration of background electrolyte (e.g. NaCl, CaCl2)- Polyvalent ions are more effective than monovalent. There is a critical electrolyte concentration for every system at which flocculation or coalescence takes place. These principles must be taken into account when emulsions have to form in very hard water. 

A similar phenomenon was observed by Muller Kretzschmar (1982) with ethylene oxide adducts at significantly increased concentration of the background electrolytes connected with clouding of the emulsion. 

In other studies, Edwards (248), Fairchild, Tonna, and Seibold (257, 258) and Frigero (293) have employed activation analysis low-background radiographic techniques to measure the boron distribution within cells in order to use Boron-10 in clinical trials of an experimental therapuetic procedure, that is, neutron capture therapy. These particular cellular distribution studies were carried out on mouse spleen, and, after the activation, the materials were exposed to photographic nuclear track emulsions of Eastman Kodak Type NTA. The countable a-particle tracks obtained in these experiments showed that concentrations of B-10 of 60 Mg/gm, the amount that can be safely delivered to tumors in human subjects, could be readily determined. In other applications of activation analysis and autoradiography, Vincent (963) and Vincent, Haumont and Roels (964) made microscopic determinations of sodium in compact bone and of bone phosphorus. 

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