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Smooth-walled

In most mixers, the metal wall has a negligible thermal resistance. The paste film, however, usually has high resistance. It is important, therefore, while minimiziug the resistance of the heating or coohng medium, to move the paste up to and away from the smooth wall surface as steadily and rapidly as possible. This is best achieved by having the paste flow so as to follow a close-fitting scraper which wipes the film from the wall with each rotation. Typical overall heat-transfer coefficients are between 25 and 200 J/(m -s-K) [4 to 35 Btu/(h-fF-°F)j. [Pg.1652]

Thus wheel arrangement is dictated by the smallest container that the line will handle. Only flat-bottomed containers can be handled on wheel conveyors, with the exception of fairly stiff-walled bags, which handle satisfac torily. This is due to the fact that the separate roller supports tend to pull the bag wall taut and flatten it out. Roller conveyors, on the contrary, tend to ripple the bag surface and prevent its movement. Wheel conveyors may also be specially designed for handling smooth-walled cyhndrical shapes. [Pg.1977]

Fig. 29. Phosphoric acid etched A606. steel surface showing smut-free, smooth-walled crevice morphology [54]. Fig. 29. Phosphoric acid etched A606. steel surface showing smut-free, smooth-walled crevice morphology [54].
Very similar to the properties of the free surface are the properties of water near smooth walls, which interact only weakly with water molecules. Many different models have been used, such as hard walls [81-83], exponentially repulsive walls [84-86], and Lennard-Jones potentials of various powers [81,87-96]. [Pg.356]

The principal effect of the presence of a smooth wall, compared to a free surface, is the occurrence of a maximum in the density near the interface due to packing effects. The height of the first maximum in the density profile and the existence of additional maxima depend on the strength of the surface-water interactions. The thermodynamic state of the liquid in a slit pore, which has usually not been controlled in the simulations, also plays a role. If the two surfaces are too close to each other, the liquid responds by producing pronounced density oscillations. [Pg.356]

Density of water 1000 kg/m3 Viscosity of water 1 mN s/m2 Assume pipes to be smooth walled... [Pg.830]

Several investigators obtained friction factors in micro-channels with rough walls that were greater than those in smooth wall channels. These observations should be considered taking into account the entrance effects, losses from change in channel size, etc. [Pg.113]

Fig. 19. A snapshot of a configuration showing a surface-induced smectic A phase near a smooth wall for the GB(3.0, 5.0, 2, 1) mesogen... Fig. 19. A snapshot of a configuration showing a surface-induced smectic A phase near a smooth wall for the GB(3.0, 5.0, 2, 1) mesogen...
With turbulent channel flow the shear rate near the wall is even higher than with laminar flow. Thus, for example, (du/dy) ju = 0.0395 Re u/D is vaHd for turbulent pipe flow with a hydraulically smooth wall. The conditions in this case are even less favourable for uniform stress on particles, as the layer flowing near the wall (boundary layer thickness 6), in which a substantial change in velocity occurs, decreases with increasing Reynolds number according to 6/D = 25 Re", and is very small. Considering that the channel has to be large in comparison with the particles D >dp,so that there is no interference with flow, e.g. at Re = 2300 and D = 10 dp the related boundary layer thickness becomes only approx. 29% of the particle diameter. It shows that even at Re = 2300 no defined stress can be exerted and therefore channels are not suitable model reactors. [Pg.48]

Soft and smooth wall Charged hard spheres Low dielectric layer... [Pg.627]

The Golay equation is strictly applicable to open tubular columns with smooth walls but, with certain approximations, it can be extended to include support-coated (77) and whisker-walled (78)... [Pg.16]

Air and water flow at 8 x 10 3 kg/s and 0.4 kg/s upwards in a vertical, smooth-wall tube of internal diameter dt = 20 mm and length L = 1.3 m. Using the homogeneous flow model, calculate the pressure drop across the tube (neglecting end effects). The fluids are at a temperature of 20 °C and the expansion of the air may be assumed to be isothermal. The exit pressure is 1 bar. [Pg.245]

As illustrated in Figure 9(2), pores can be straight with smooth walls or can be branched. The branched pores can have... [Pg.164]

For pores of extremely small diameters, in the order of a few nm, the direction of individual pores is totally random. On the other hand, large pores tend to have less anisotropic effect and grow more dominantly in the direction of carrier supply, that is, perpendicular to the surface. The macro pores formed on p-Si generally have smooth walls and an orientation toward the source of holes that is perpendicular to the surface, even on (110) and (111) samples.34,39... [Pg.169]

Figure 14. Straight pores with smooth wall formed on n-Si in the dark.1... Figure 14. Straight pores with smooth wall formed on n-Si in the dark.1...
Pores with smooth wall tend to be aligned with source of holes, while dendritic pores are aligned with <100> directions. [Pg.177]

Figure 5.21 a shows an SEM micrograph (in cross section) of a feature ablated in doped PTFE, specifically 0.5% polyimide, at 12 J/cm2. The ablated feature is well defined and exhibits a smooth wall profile, typical of all blends having more than 0.1% (wt/wt) polyimide. The sidewall profiles of the less heavily doped blends are extremely vertical, having less taper than typically observed for more heavily doped PTFE films, e.g., 1.0 and 5.0% (Figures 5.21b and 5.21c, respectively) or Upilex-S polyimide, (Figure 5.21d). Ablation rates for a variety of PI-PTFE blends [0.2-5% polyimide (wt/wt) and neat polyimide] at 248 nm and 308 nm are shown in Figures 5.22 and 5.23, respectively.78... Figure 5.21 a shows an SEM micrograph (in cross section) of a feature ablated in doped PTFE, specifically 0.5% polyimide, at 12 J/cm2. The ablated feature is well defined and exhibits a smooth wall profile, typical of all blends having more than 0.1% (wt/wt) polyimide. The sidewall profiles of the less heavily doped blends are extremely vertical, having less taper than typically observed for more heavily doped PTFE films, e.g., 1.0 and 5.0% (Figures 5.21b and 5.21c, respectively) or Upilex-S polyimide, (Figure 5.21d). Ablation rates for a variety of PI-PTFE blends [0.2-5% polyimide (wt/wt) and neat polyimide] at 248 nm and 308 nm are shown in Figures 5.22 and 5.23, respectively.78...
The quality of the tube innerwall can have a profound effect on the efficiency of the column. Smooth-walled tubes yield best results imd as a rule of thumb the roughness of the sur ce should not be greater ilian the particle diameter of the colunm material. In most instances No. 316 stainless steel is used because this material withstands aqueous solutions in a broad pH range. Nevertheless the presence of halides, particulaHy in acidic eluents, causes corrosion of this material. ... [Pg.246]

Princen [57, 64, 82] and others [84] also noted the presence of wall-slip in rheological experiments on HIPEs and foams. However, instead of attempting to eliminate this phenomenon, Princen [64] employed it to examine the flow properties of the boundary layer between the bulk emulsion and the container walls, and demonstrated the existence of a wall-slip yield stress, below that of the bulk emulsion. This was attributed to roughness of the viscometer walls. Princen and Kiss [57], and others [85], have also showed that wall-slip could be eliminated, up to a certain finite stress value, by roughening the walls of the viscometer. Alternatively [82, 86], it was demonstrated that wall-slip can be corrected for and effectively removed from calculations. Thus, viscometers with smooth walls can be used. This is preferable, as the degree of roughness required to completely eradicate wall-slip is difficult to determine. [Pg.180]


See other pages where Smooth-walled is mentioned: [Pg.474]    [Pg.643]    [Pg.1850]    [Pg.357]    [Pg.159]    [Pg.120]    [Pg.178]    [Pg.157]    [Pg.7]    [Pg.165]    [Pg.170]    [Pg.171]    [Pg.234]    [Pg.239]    [Pg.240]    [Pg.181]    [Pg.88]    [Pg.95]    [Pg.343]    [Pg.391]    [Pg.490]    [Pg.201]    [Pg.201]    [Pg.25]    [Pg.474]    [Pg.288]    [Pg.334]   
See also in sourсe #XX -- [ Pg.65 , Pg.68 , Pg.78 , Pg.351 ]




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Packings packing with vertical smooth walls

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