Settling time experiment

Like any sequence of events, an FFC experiment can be intended as a sequence of elementary intervals during each of which all system control lines maintain constant values. One needs to keep in mind, however, that while a control line transition is always very fast (settling times of the order of Ins), the controlled device/parameter may require a much longer... 

Because of the variety of factors influencing settling time, it will vary considerably from one system to another. Preliminary bottle tests wilt give some indication and this, combined with experience and theoretical data, will allow for a pretty good prediction of the required time. 

The dispersions prepared in the first five experiments listed in Table IV were very stable. The settling data of these samples are plotted in Figure 5. The amount of adsorbed block copolymer in the treatment at room temperature is in about the same range as the pick-up previously obtained with the heat treatment methods, and the total settling times of the best dispersions in Table IV are even somewhat higher than the values previously obtained. At very high degrees of carboxylation (ex-... 

Hydraulic Behavior. The influence of the main DMDOHEMA degradation products on the hydraulic performances of the process flowsheet was investigated by the determination of the emulsion settling time after mixing the irradiated solvent with nitric acid solution (0.1 mol I. ). This settling time increased with the irradiation dose. Experiments performed with synthetic solutions of monoamide and... 

These workers were not able to correlate the values of k or of settling time with any more general properties. To free the correlation from the restriction imposed by the presence of factors which could be determined only by specific experiments, the following relation was given ... 

Countercurrent chromatography (CCC) is based on the use of two-phase liquid solvent systems. One of the characteristics of a two-phase system is its settling time, which is the time required for the mixture of both phases to be completely separated into two layers, usually in the Earth s gravitational field. The measurement of the settling time itself is helpful in preparing the experiment, for instance, when preparing the mobile and stationary phases in the same vessel. However, it is also intrinsically linked to the hydrodynamic behavior of the two-phase system and, therefore, to its physical parameters such as densities, viscosities, and interfacial tension. It was, therefore, used as a parameter for predicting the hydrodynamic behavior of various solvent systems in J-type CCC devices. 

It was further demonstrated that this theoretical parameter was the right one to use, as Menet et al. have carried out experiments on the evolution of the hydro-dynamic behavior of the butanol-1-water system with the temperature [3]. They showed that the observed change in behavior was explained by an increase in the y p settling velocity with the temperature, and, thus, a decrease of the settling time, explaining the hydrophobic behavior of the solvent system. 

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