Plug Size

4 Liquid-Liquid Flows in Micro and Small Channels. .. 

14 Plug shape at a low and b high total volumetric flow rate in a 2 mm ID channel 

The effect of volume fraction of the dispersed phase on plug length at constant mixture velocity and at constant velocity of the carrier phase is shown in Fig. 4.13. In all channel sizes the length of the plug was found to increase as e j increased. Moreover, shorter plugs are formed for the whole range of as the velocity of the carrier fluid increases Fig. 4.13b. 

A correlation (Eq. 4.3.1) to describe the different parameters, as well as the properties of the fluids that affect the plug length has been developed, that takes into account the Ca number of the mixture in the main channel, the Re numbers of each phase in the inlet channels (based on superficial velocities), the Re number of the mixture in the main channel (based on mixture velocity), the flow rate ratio q = Qil/ Qhno3 and the diameter of the channel. In Fig. 4.15 the results tabulated are from 4 channel sizes, for mixture velocities from 0.0028 to 0.067 m s and flow rate ratios from 0.5 to 1.5. The viscosity ratio Pd/Pc has not been taken into account since it was 1/29, and the Ca number were less than 0.1, so it does not affect the plug size (Christopher et al. 2008 Liu and Zhang 2009). 

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The plug size is 0.5 gm in diameter, and the oxide erosion measurement is... 

Scheme 13 Microwave-assisted displacement of an aromatic chloride by a 2° amine used to evaluate the effect of plug size in the continuous flow reactor.

Other applications of lactose include use in lyophilized products, where lactose is added to freeze-dried solutions to increase plug size and aid cohesion. Lactose is also used in combination with sucrose (approximately 1 3) to prepare sugar-coating solutions. 

Injection valves have been used to introduce samples into a capillary electrophoresis instrument. The injection system is similar to a six-port valve used in a conventional HPLC instrument, where the sample can be loaded into a sample loop on the valve, then the valve actuated to inject the plug onto the capillary. The size of the injection is determined by the plug size and flow rate. This system is not the fastest or most reproducible, but it relies on fairly simple technology. Valved injections have been used in conjunction with separation times down to 10 s. ... 

Figure 3.19 Dimensionless plug velocity and plug size for laminar Bingham plastic flow in an annulus...

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