Droplet size factors affecting

The mechanism of droplet deformation can be briefly summarized as follows. The factors affecting the droplet deformation are the viscosity ratio, shear stress, interfacial tension, and droplet particle size. Although elasticity takes an important role for general thermoplastics droplet deformation behavior, it is not known yet how it affects the deformation of TLCP droplet and its relationship with the processing condition. Some of... 

In practical fan sheet breakup processes, sheet thickness diminishes as the sheet expands away from the atomizer orifice, and liquid viscosity affects the breakup and the resultant droplet size. Dombrowski and Johns[238] considered these realistic factors and derived an analytical correlation for the mean droplet diameter on the basis of an analysis of the aerodynamic instability and disintegration of viscous sheets with particular reference to those generated by fan spray atomizers ... 

A theoretical study of factors which affect pneumatic nebulizers (nebulizer geometry, capillary diameter, temperature fluctuations, gas pressure, solution viscosity, etc.] has been published by Heineman (24). Ultrasonic nebulization (which produces both smaller droplets and a narrower droplet size distribution] continues to attract attention (93, 95). 

Some ofthe factors that affect the physical stability of emulsions include the type and concentration of surfactant used to stabilize the emulsion, the phase volume ratio (i.e., ratio of oil to aqueous phase), droplet size, compatibility of drug and excipients with the emulsion, and storage condition ofthe emulsion. 

Once good physical stability of an emulsion is insured, its commercialization mandates chemical stability of the incorporated drug and other essential components for at least 18 months. Key factors that affect the chemical stability of pharmaceutical emulsions include drug stability in oil, drug stability in aqueous media, drug concentration in oil and emulsion, phase volume ratio, droplet size, presence of excipients, and presence of air and/or peroxide radicals. As mentioned earlier, choice of appropriate antioxidant is important. 

Emissions of soot on the other hand represent a smaller fraction of the overall emission, but are probably of greater concern from the standpoint of visibility and health effects. It has been suggested that soot emissions from fuel oil flames result from processes occurring in the vicinity of individual droplets (droplet soot) before macroscale mixing of vaporized material, and from reactions in the bulk gas stream (bulk soot) remote from individual droplets. Droplet soot appears to dominate under local fuel lean conditions (1, 2), while bulk soot formation occurs in fuel rich zones. Factors which are known to affect soot formation from liquid fuel flames include local stoichiometry, droplet size, gas-droplet relative velocity and fuel properties (primarily C H ratio). 

Effect of Emulsion Characteristics. As discussed in Chapter 4, the rheology of emulsions is affected by several factors, including the dis-persed-phase volume fraction, droplet size distribution, viscosity of the continuous and dispersed phases, and the nature and amount of emulsifying surfactant present. All of these parameters would be expected to have some effect on flow behavior of the emulsion in porous media. However, the relationship between bulk rheological properties of an emulsion and its flow behavior in porous media is feeble at best because, in most cases, the volume... 

Phipps, Paul,R. Gonda, Igor. Droplets produced by medical nebulizers some factors affecting their size and solute concentration. Chest 1990, 97 (6), 1327-1332. 

Two mtyorlactors affect droplet size and density in the PIPS process types and relative concentration of materials used and cure temperature. The cure temperature influences the rate of polymerization, viscosity of the polymer, diffusion rate of the liquid crystal and solubility of the liquid crystal in the polymer. Each factor is affected differently by the cure temperature with the result that droplet size varies in a complex manner with cure temperature (Figure 5) and must therefore be empirically determined for each formulation. 

The combustion of sprays in a high-temperature furnace is a complex physical and chemical process that involves simultaneous heat, mass and momentum transfer, phase transition, and chemical reactions. The droplet size, composition of the fuel, ambient temperature and pressure, and oxygen concentration are major factors that affect the combustion process. Owing to the complexity of the process, it is very difficult to obtain accurate information on the combustion of the spray. However, the evaporation and combustion of a single droplet of oil have been well studied since it is relative easy to carry out an experiment for the measurement of combustion. Furthermore, it has been theoretically investigated due to its simplicity. 

In a recent summary report, the SDTF state that from their studies droplet size was the most important factor affecting spray drift. Their studies support the view that the physical properties of the spray mixture generally have a small effect relative to the combined effects of equipment parameters, application technique and the weather . 

Whitehead et al [1983] point out that the Conradson carbon residue test has a poor correlation with measured particles in the combustion gases. They suggest that the differences are probably due to the very different conditions in the laboratory bench test compared with the practical combustion conditions. In an industrial furnace the oil droplets undergo a high heating rate and under these conditions the level of pyrolysis residue (coke) formed can be considerably reduced. Droplet size (a fonction of atomiser design and performance) is likely to be an important factor that affects the droplet heating rate as described earlier. 

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