Size removal, rate

The fabric is desized after the weaving operation and then passed through a heated water bath to remove all the size. The rate at which this operation can be accompHshed depends to a great degree on solubiUty rate of the poly(vinyl alcohol). Difficulties encountered in completely removing the lubricating wax, usually tallow wax, has led to the development of several wax-free size compositions (303—311). The main component contained in these blends is PVA in combination with a small amount of a synthetic water-soluble lubricant. 

Classified removal of course material also can be used, as shown in Figure 16. In a crystallizer equipped with idealized classified-product removal, crystals above some size ate removed at a rate Z times the removal rate expected for a perfecdy mixed crystallizer, and crystals smaller than are not removed at all. Larger crystals can be removed selectively through the use of an elutriation leg, hydrocyclones, or screens. Using the analysis of classified-fines removal systems as a guide, it can be shown that the crystal population density within the crystallizer magma is given by the equations... 

Although many commercial crystallizers operate with some form of selective crystal removal, such devices can be difficult to operate because of fouling of heat exchanger surfaces or blinding of screens. In addition, several investigations identify interactions between classified fines and course product removal as causes of cycling of a crystal size distribution (7). Often such behavior can be rninirnized or even eliminated by increasing the fines removal rate (63,64). 

CMP of HDD substrate in four kinds of slurries, each with a different mean particle diameter of 15,30,50, and 160 nm as shown in Fig. 33, was conducted by Lei and Luo [43]. The dependences of Wa, Ra, and material removal rate on the Si02 particle size are shown in Figs. 34(a)-34(c), respec-... 

Fig. 34 —Effect of the particle size on (a) surface waviness Wa, (b) surface roughness Ra, and (c) material removal rate. The slurry contains 5 wt % SIO2 particles, 1.5 wt % oxidizer, and 1 wt % lubricant In Dl water at pH 1.8.

Luo and Domfeld [110] introduced a fitting parameter H , a d5mamical" hardness value of the wafer surface to show the chemical effect and mechanical effect on the interface in their model. It reflects the influences of chemicals on the mechanical material removal. It is found that the nonlinear down pressure dependence of material removal rate is related to a probability density function of the abrasive size and the elastic deformation of the pad. 

Zhou, C. H., Shan, L., and Hight, R., "Influence of Colloidal Abrasive Size on Material Removal Rate and Surface Finish in Si02 Chemical Mechanical Polishing, Tribol. Trans., Vol. 45,2002, pp. 232-230. 

Fines removal, the selective removal of small crystals from a well-mixed crystalliser, is generally used to remove excessive fines, thus increasing the average size. An increase in the fines removal rate immediately reduces the number of small crystals contained in the reactor. 

It is dispersed by wind and removed by gravitational settling (sedimentation), dry deposition (inertial impaction characterized by a deposition velocity), washout by rain (attachment to droplets within clouds), and rainout (scrubbing action below clouds) (Schroeder et al. 1987). The removal rate and distance traveled from the source depends on source characteristics (e.g., stack height), particle size and density, and meteorological conditions. 

The vesicular size might go back reversiblly to the original one in the case of nonionic vesicles (Figures 9 and 10) for which the present removal rate may be too slow. A similar behavior was reported by Schurtenberger et al. for their lecithin-bile salt systems vesicle size is reduced to the original dimension after dialysis of remains large when the solubilized is diluted with the buffer solution to very fast reduction of bile salt fast removal of bile salt(22) ... 

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