Breaking, bubble

Film. By far the largest appHcation for LLDPE resins (over 60% in the United States) is film. Because LLDPE film has high tensile strength and puncture resistance, it is able to compete with HDPE film for many uses. The toughness and low temperature properties of LLDPE film also exceed those of conventional LDPE. Furthermore, because LLDPE resins exhibit relatively low strain hardening in the molten state and lower extensional viscosity, it can be produced at high rates with Httle risk of bubble breaks. 

In boiling convection, liquid motion is created by steam bubbles breaking loose from the surface. 

Fig. 4 shows the accumulated standard deviation error, ss, with the measuring time of the pressure fluctuation for a good fluidization case (a) and a locally poor fluidization case (b). Pressure 1 and 2 were measured at the exit and the center air-headers of the FBAC respectively. Pressure 3 and 4 were measured at the entrance air-headers of the FBAC. As shown in Fig. 4 (a) and (b), the accumulated standard deviation error, ss, stayed in a limited range if the bed is in good fluidization state, but ss for the entrance of the FBAC decreased steadily if the bed is in local poor fluidization state. This may be Ifom the decrease of the bubble explosion force and frequency, which have influence on the standard deviation enxir of the pressure fluctuation, at the bed surface due to the bubble break and bypass around the poor fluidization area. Therefore, we can easily detect the local poor fluidization through this simple method. Additionally, as detecting the local poor fluidization, we could also regulate the overall or local airflow rate to clear up the local poor fluidization, as shown in Fig. 5. The accumulated standard deviation error, deviated from a limited range due to poor fluidization, shows to return into a limited value after regulations of local airflow rates.

At high gas velocities in the bed, the stable bubbles break down into unstable voids that continuously disintegrate and reform. This type of bed is said to be operating in the turbulent fluidized-bed regime, and is characterized by higher heat- and mass-transfer rates than in the bubbling bed. As the gas velocity is increased further, the... 

For cracker catalyst (d = 55 (im, density = 950 kg/m3) fluidised by air, values of umb/umf of up to 2.8 have been found by Davies and Richardson(45). During the course of this work it was found that there is a minimum size of bubble which is stable. Small bubbles injected into a non-bubbling bed tend to become assimilated in the dense phase, whilst, on the other hand, larger bubbles tend to grow at the expense of the gas flow in the dense phase. If a bubble larger than the critical size is injected into an expanded bed, the bed will initially expand by an amount equal to the volume of the injected bubble. When, however, the bubble breaks the surface, the bed will fall back below the level existing before injection and will therefore have acquired a reduced voidage. 

As a result of gas flow into a bubble, the mean residence time of the gas in such systems is reduced because the bubble rises more rapidly than the gas in the continuous phase. Thus, the injection of a single bubble into the bed will initially cause the bed to expand by an amount equal to the volume of the bubble. When this bubble breaks the surface of the bed, however, the bed volume decreases to a value less than its initial value, the gas content of the bed being reduced. If the value of uc is only slightly in excess of umf, the gas in a small injected bubble may become dispersed throughout the continuous phase so that no bubble appears at the surface of the bed. 

The addition of solids has been found to increase or even decrease the gas holdup, depending on the experimental conditions. When the solids addition promotes bubble break up, the average bubble size is smaller, the bubble rising velocity is reduced, and the gas holdup increases (DOE, 1985). The following correlation of Koide et al. (1963) is used in slurry bubble columns and for the heterogeneous and transition regimes (Koide et al., 1984 Koide, 1996) ... 

Today s Post-Its are made with a very sophisticated technology. We can actually reuse them, because their adhesive is contained within thousands of little bubbles of urea formaldehyde resin. These bubbles break under pressure, but they don t all break at the same time. So, how many times can a Post-It be reused I don t know. I should do an experiment. I ll leave myself a note to do just that. On a Post-It, of course. 

Defoamlng plates. Foam at the interface may occur as gas bubbles break out of the liquid. Foam can be stabilized with addition of chemicals at the inlet. Often a more effective solution is to force foam to pass through a series of inclined... 

At low liquid depths (i.e., very low liquid loads), bubbles break the liquid surface before detaching from the tray orifices, causing nonuni-formity and some unique performance characteristics (40). This region ilow vapor loads and very low liquid loads), however, is infrequently encountered in industrial practice. 

Increasing anode potential beyond the limiting current plateau range may cause gas bubbles to form on anode surface. The gas bubbles break anodic layers and thus mass transport controlled condition. Hence, the current-potential relation becomes linear again. Gas bubbles produced on anode lead to a rough surface [4]. 

The effect of oil upon foam stability has been explained in rather general terms through the mechanism of oil spreading phenomena, but the reason why the oil droplets spread and the film between the oil droplets and air bubbles breaks has not been discussed. 

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