Drop size distribution bimodal

The above reasoning leads to flie following characteristics for the proper product an OAV emulsion, located at 70% oil (for adequate ealoric content), a few SAD units from optimum formulation (for stabihty), and with 10— 30 pm drops with a bimodal drop size distribution (for low viscosity and satisfactory combustion). 

Drop sizes depend on many factors that are discussed throughout this chapter. For any given system, drop sizes are never uniform rather, they exist in a continuous size spectrum. The large end of the drop size spectrum is controlled by agitation intensity, and the small end by the physics of drop breakage events. The DSD is sometimes bimodal or trimodal. Multimodal distributions are usually a result of multiple breakage mechanisms and unusual breakage patterns, such as those that result when viscous and/or viscoelastic drops are dispersed. Certain coalescence events can also lead to bimodal drop size distributions. 

Once the average drop size is set, the viscosity can be further curtailed by another effect, i.e., by manipulating the drop size distribution shape. In effect, it is known that a polydispersed emulsion, or even better, a bimodal emulsion, will exhibit a redueed viscosity. 

From what we said about the character of drop breakage, it follows that the function g(y) is bimodal with two distinct maxima, one of which is in the interval of satellite sizes, and the other - in the interval of daughter drop sizes. Then it can be presented as a sum of two weighed unimodal distribution densities gi(y) and giiy), defined on the interval (0,1) and having the average values gj = Vi/[Pg.344]

Provided that the emulsion remains stable over the change, the drop size stays constant, as do other related properties. If the internal phase content is increased by adding some amount of thi.s phase (under constant stirring as along path i in Fig. 21, emulsion viscosity is expected to augment from the increase in internal phase content, although other effects would have to be taken into account, such as the efficiency of the stirring required to proceed with emulsification of the added internal phase, or the eventual production of a bimodal distribution that could result in a viscosity reduction. 

Since the conductivity of electrolytes and the cross section and thickness of the membrane are known, a can be determined from the voltage drops across the three pairs of probe electrodes 1-2, 3-4 and 5-6. The sodium current efficiency (CE) can also be determined by titrating the amount of caustic soda generated over a given period of time. The confinement chambers around the working electrodes are used to eliminate free bubbles near the membrane. Our normalized transport data for sulfonate, carboxylate and sulfonamide ionomers are plotted In Figure 5 the universal percolative nature of perfluorinated ionomers can be clearly eeij. The prefactor sulfonate ionomers. The exponent t is 1.5 0.1 in reasonable agreement with theory and the thresholds are between 8 to 10 vol. %, which are consistent with the bimodal distribution in cluster size postulated by the cluster-network model (5.18). This theory has also been applied recently to delineate sodium selectivity of perfluorinated ionomers (20). 

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