DEGREE OF FOAMING

In the urethane process a small amount of water is added to convert some isocyanate functionalities into CO2 gas and amines. The degree of foaming can be controlled by the amount of water added. 

To simulate unti-foam failure, injection into the crude was reduced or stopped to induce various degrees of foam mg in the scpaiators. The foam that carried over was divened into the relief system, which was designed for both gas and liquid relief. 

Residence time is crucial in the degree of foaming that occurs. Although Ninian live crude usually forms a more stable foam than most other crudes, plant investigations have shown that operation without anti-foam chemical ad dition is possible at only about 40% of design crude throughput. 

In coffee products, such as espresso, a stable foam is an important aspect of overall product quality, in addition to smell, taste, colour, and body [857]. In addition to appearance, a foam layer helps trap coffee aromas, providing a more gradual release. The degree of foaming has been found to increase with the degree of roast and the amount of protein in the coffee, while the stability of the produced foam has been related to the amounts of galactomannan and arabinogalactan [857]. 

The mold can be modified to meet certain different shapes. The molding can be made either by withdrawing cores or by special press motions that partially open the mold halves (such as the compression molds used in coining to provide 2-D action 3-D mold actions are also used). The degree of foam density, wall thickness, and surface finish depends on the foam mixture (constituents and amounts). The machine controls the time cycle and the mold action required. 

The accuracy of the discussed technique for measuring bubble size is influenced mainly by the degree of foam polyhedricity and by the precision of pressure measurement with the micromanometer. With the increase in Ap this precision increases. For dry foams the error... 

INTEX LEVELER 152 is an anionic/nonionic emulsified dye carrier. It has virtually no odor and provides an excellent color yield while maintaining a low degree of foam. 

STEROX DJ surfactant is an all-purpose surfactant with a generally lower degree of foaming compared to other alkylphenol-based nonionics. It is an extremely effective detergent at temperatures below 38C (100F) and can be compounded with phosphates and the usual detergent builders for a wide range of applications. 

Provided that G > Gp (for liquid foams x of solutions > x of air) we obtain Eq. (39) from Eq. (41) by substitution of k instead of G. In contrast to Wagner s formula, Odelevsky s formula holds for all concentrations of the disperse phase (gas) and for all types of gas-filled systems gaseous emulsions (d < 0.74), spherical (0.74 < d< 0.9) and polyhedral ( > 0.9) foams. It requires isotropy of the matrix structures and equal diameters of the disperse phase inclusions. Therefore, the dependence of the ratio of the foam to the solution electroconductivity on the degree of foaming in the general form is given by equation... 

Factors for correcting the allowable volumetric rate for various degrees of foaming are given with the figure. 

This test method is useful in determining the effect of using adhesives on rigid cellular polystyrene (RCPS) foam in building construction. The method covers a practical means of measuring the degree of foam cavitation damage when an adhesive is used to bond these foam substrates. 

The degree of foaming tendency may be checked by laboratory foaming tests, but it is difficult to predict what effect a given degree of foaming may have on tray capacity. 

The spreading and entering coefficients have correlated with foam sensitivity to oil in a number, but not in all, of the cases. As already noted, the degrees of foam sensitivity to oil (Figure 2) observed in microvisual experiments have been compared to the thermodynamic predictions based on S and E in Figure 8 (37, 40, 47). In these comparisons, the predictions were not always borne out Depending on the oil studied, on the order of one-half of the surfactant solutions predicted to produce foams of type C actually produced foams of type B. The predictions of which surfactants would produce foams of type A were much better for the heavier oils than for the lighter oils. Even quantitative measurements of lamella rupture frequency in the microvisual experiments showed that satisfactory correlations with 5 or were not obtained (37, 40, 47). 

However, although the bulk volumetric gas flow rate can be directly scaled, the superficial gas velocity — that is, the velocity of the gas rising through the liquid — can be markedly different between the laboratory and plant scale leading to different degrees of foaming and liquid swell on the plant scale. 

Chemical structure of base polymer Degree of crystallinity Degree of foaming Fillers... 

Surfactants are necessary in the RIM urethane elastomer process where some degree of foaming is desired in the final moulding. They are added to the foam formulation to decrease the surface tension of the system and facilitate the dispersion of water in the hydrophobic medium, aid in nucleation, stabilize the foam and regulate cell structure. The choice of surfactant depends upon the type of foam preparation (polyester, prepolymer or one-shot polyether). Both ionic and non-ionic surface-active agents have been employed. 

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