Foam, quality

The numerous previous studies of the flow of foam in porous media and of its application for. improving the displacement of oil from such media, have almost always been conducted under ambient conditions of temperature and pressure there have been very few reports of laboratory studies under reservoir conditions. Although many interfacial properties are known to be temperature dependant, little attention has been paid to the influence of temperature upon the properties of foam. Furthermore, the rheological properties of foams, and their effectiveness for the displacement of oil are strongly dependant upon foam quality, which is in turn... 

Consideration of the slope of the effluent weight/time curve just after gas breakthrough, shown in Figure 3, indicates that the foam first breaking through had a quality of about 60%, whilst that emerging near the end of the run has a quality of approximately 92%. The foam quality at intermediate... 

In general, foams will be more stable when they are generated with water at ambient or lower temperature. Preferred water temperatures range from 35 to 80°F (2 to 27°C). Either fresh or seawater may be used. Water containing known foam contaminants, such as detergents, oil residues, or certain corrosion inhibitors, may adversely affect foam quality and appropriate steps should be taken to ensure an adequate supply of suitable quality water. See NFPA 11 for more information on application rates. 

Using a laboratory technique previously developed to evaluate the performance of chemical foaming agents in XLPE foam, metallocene polyolefins are evaluated at various addition levels to branched LDPE to determine their effect on general foam quality (cell size, density, appearance). The laboratory method is discussed, and conclusions on acceptable levels of the metallocene resins are offered. 5 refs. 

The ethylenic polymer material contains a linear ethylenic polymer having a specified melt flow ratio, a defined MWD and a critical shear rate at onset of snrface melt fractnre of at least 50% greater than the critical shear rate at the onset of surface melt fracture of a linear olefin polymer having similar characteristics. The foam stmctnres have toughness and elasticity similar to those formed from conventional LLDPE without the poor dimensional stabihty and foam quality associated with those structures. They also have foam quality similar to those made with conventional LDPE but with enhanced tonghness and elasticity. The foam structure may also be made in a foam bead form. 

Lowering the temperature produces the opposite effect. The polymerization reaction depends on abstraction first the balance of the reaction favors polymerization, and a high-density foam is produced. This is a complicated effect when incorporating a temperature-sensitive component in the foam. We will discuss the addition of living cells into a foam sample later. Controlling the temperature is an important consideration. Unfortunately, foam quality is sacrificed because the reaction must be conducted at reduced temperatures. 

Some important aspects of foam are not included in this list. We mentioned void volume earlier. This parameter is related to density by a comparison of bulk density to absolute density. We will discuss each of these measures of foam quality and relate their applicability to the theme of this book. Later in the chapter we will show how formulation and processing techniques are used to adjust and control the most important parameters. 

The reactions of some protein with isocyanate removes some of the reactant from its normal role in the production of CO2. This detracts from the quality of the foam. Because foam quality is critical to fulfilling the physical requirements of an... 

RJH Wilson, TR Roberts, RJ Smith, LL Bradley, M Moir. The inherent foam stabilizing and lacing properties of some minor, hop derived, components. EBC Symposium on Beer Foam Quality, 1998, pp 188-207. 

The gas volume fraction in a foam. Expressed as a percentage this fraction is sometimes referred to as the Mitchell foam quality . In three-phase systems, other measures are used. For example, when foams are formulated to contain solid particles as well, the slurry quality, Qs, which gives the volume fraction of gas plus solid, can be used Qs = (Vg + Vs)/(Vg + Vs + Vi), where Vg, Vs, and Vi denote the volumes of gas, solid, and liquid phases, respectively. 

Mist Drilling Fluid Mitchell Foam Quality Monodisperse... 

In suspensions, the concentration of solid particles. In foams containing solids, the volume fraction of gas plus solid in the foam. See also Foam Quality. 

The studies indicated that for all foaming agents the efficiency of oil recovery increased with the rise in foam quality. The authors explained this with the apparent viscosity of the foam. The analysis of other studies of the same authors showed that similar increase was observed in unconsolidated porous media with high porosity (0 > 0.35) and high permeability (K > 10 mm2). For consolidated pores with low porosity (0 < 0.25) and low permeability (K < 0.2 pm2) a decrease in oil recovery with the increase in foam quality occurred. 

The studies published by Senee et al. (1999, 2001) show that the endogenous particles (bentonite and yeasts) that can exist in a wine also have an important effect on foam quality, simultaneously having both positive and negative effects, since they have different effects on the various foaming parameters. 

Most of the studies published in the literature on sparkling wine quality are aimed at establishing the effect of the chemical composition of these wines and the different technologies used in their production on their foaming qualities. 

Gallart et al. (2002) have demonstrated that the fatty acids Cg, Cio and C12, do indeed damage the foaming qualities of the wines, but some fatty acid esters actually cause an improvement. Pueyo et al. (1995) have reported previously that linolenic acid when not present in the free state (forming part of another type of lipid) is positively correlated with foam quality. 

Several authors also agree that sulphur dioxide can negatively affect the foaming qualities of wines (maujean 1990 Pueyo et al. 1995 Ldpez-Barajas et al. 1997 Girbau-Sola et al. 2002b), as can ethanol, as mentioned above (Molan et al. 1982 Dussaud et al. 1994 Girbau-Sdla et al. 2002b). 

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