Agglomerate size

Clarke,. 1. and Freakley, P.K., 1995. Modes of dispersive mixing and filler agglomerate size distributions in rubber compounds, Plast. Rubber Compos. Process. Appl. 24, 261-266. 

Figure 6.15 Predicted and experimental calcium oxalate agglomerate size distributions (Hartel and Randolph, 1986)...

In the stirred tank, the final mean size of particles was reduced by the increase of stirring rate, being consistent with increased fluid shear induced particle disruption relative to aggregation. Use of three different gas velocities in the bubble column, however, results in no significant difference in agglomerate size but since the size is relatively small, it may simply reflect an asymptotic value. 

Here, both concentration and size are rescaled with respect to the average agglomerate size. (/) as... 

Fig. 36. The spatial variation of agglomerate sizes in simulations of erosion in the journal bearing flow. Initially there are 10000 agglomerates consisting of 400-500 aggregates. The grey scale represents the number of aggregates in the agglomerates, (a) Poorly mixed flow after four periods, (b) Well-mixed flow after one period (Hansen, el al. 1998).

At the simplest level, the rate of flow-induced aggregation of compact spherical particles is described by Smoluchowski s theory [Eq. (32)]. Such expressions may then be incorporated into population balance equations to determine the evolution of the agglomerate size distribution with time. However with increase in agglomerate size, complex (fractal) structures may be generated that preclude analysis by simple methods as above. 

Analytical approaches to obtain the agglomerate size distribution are possible for well-mixed systems and when the rate of aggregation of clusters is defined by simple functions. In general, irreversible aggregation in well-mixed systems is described by Smoluchowski s coagulation equation, which... 

FIGURE 2.1 Change of electrical conductivity with respect to Ni content in the Ni-YSZ cermets at 1,000°C. Two types of YSZ were used to prepare the cermets one was Toyo Soda powder with a specific surface area of 23 m2/g and an agglomerate size of -0.3 pm, and the other was Zircar powder with a specific surface area of 47 m2/g and an agglomerate size of -0.1 pm the NiO used has a specific surface area of 3.5 m2/g. (From Dees, D.W. et al., J. Electrochem. Soc., 134 2141-2146, 1987. Reproduced by permission of ECS-The Electrochemical Society.)... 

Catalytic activity and electrochemical performance generally increase as the NiO and YSZ particle sizes are reduced. However, ultrafine powders are prone to agglomeration during the milling and mixing process the distributions of the phases (and hence the percolation threshold and many other important properties) are determined by the agglomeration size, not by the primary particle size. 

The 11 nm-sized Ti02 were crystallized using either hydrothermal or thermal methods from 100 nm, amorphous gel spheres. The Ti02 crystal and agglomerate sizes were determined by X-ray diffraction (Philip 1080) and transmission electron microscopy (JEOL JEM 2010), respectively. The surface area and chemistry of the nanostructured Ti02 were analyzed by nitrogen physisorption (Coulter SA 3100) and Fourier transform infrared spectroscopy (FTIR, Perkin-Elmer GX 2000). Metal catalyst was deposited by incipient... 

According to Sohnel and Mullin(29), the change in agglomerate size as a function of time may be represented by equations of the form ... 

Other efforts have also been made to modify the CL microstructure by controlling the agglomerate size in the catalyst ink. Uchida et al. [145] proposed a colloidal ink fabrication procedure using low-dielectric-constant solvents to generate a good network and a uniformity of perfluorinated... 

Ageing of the sol profoundly affects the casting behavior. After ageing (e.g. one week) gel layers could be formed on type 2 supports while before ageing this was not found to be the case. This points to an increase of the agglomerate size of the boehmite particles in accordance... 

Figures 9a and 9b show the SEM pictures of the alumina powders before and after milling. Note that the magnifications of Figs. 9a and 9b are different. In other words, milling has significantly reduced the agglomerate sizes from those in Fig. 9b to those in Fig. 9a.

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