Interfacial location, solid-liquid

The book consists of four chapters. The first one deals with the individual components of the studied systems the solid, the solution, and the interface. Solid means rocks and soils, namely, the main mineral and other solid components. In order that the solid/liquid interactions become possible, these must be located in the Earth s crust where groundwater is present. The liquid phase refers to soil solutions and groundwater, and also any solutions that are part of laboratory experiments studying interfacial properties with the objective of understanding the principles behind the reactions. In Chapter 1, the characteristics and thermodynamics of the... 

The molecules that are located at the phase boundaries (that is between solid-gas, solid-liquid, liquid-gas and liquidi—liquid2) behave differently to those in the bulk phase. This rule generally does not apply for solid-solid and gas-gas interfaces where atomic and molecular bonding in the solid structure restrict the reorientation of interfacial molecules for the former, and the ease of miscibility of different gas molecules in free space does not allow any interface formation for the latter. 

The surfactant solution in the reservoir can alter the interfacial tension at solid/liquid and gas/liquid interfaces, which in turn influences the capillary number. For a capillary controlled di lacement, the leading spherical interface becomes unstable if its capiLLary pressure is less than the capillary pressure at the throat. Roof considered toric pores and computed the equilibrium location of the leading front as a function of tore radius. The front (head meniscus) is always at least seven pore radii from the throat of the constriction before snap-off (choke-off) can occur. He made an experimental verification of the theoritical analysis. His experimental observations showed that irregularity in the pore seems to be necessary for a snap-off process to occur within reasonable periods of time. 

Adsorption can be most simply defined as the preferential concentration (i.e., location) of one component of a system at an interface, where the local (i.e., interfacial) concentration of one or more components of one or both phases is different from those in the bulk phases. Adsorption should be clearly differentiated from absorption, in which physical penetration of one phase into another is involved, although the two may operate concurrently. Adsorption can occur at any type of interface, although the distinct characteristics of solid versus liquid interfaces make the analysis of each case somewhat different. For that reason, the discussion of each situation is best presented in the context of specific interfaces. In many practical systems, all four of the principle interfaces may be present, leading to complex situations that make complete analysis very difficult or impossible. 

There are analogies between the minimum impeller speed Njs for solids suspension and Nmm for drop suspension. Both depend on density difference, continuous phase viscosity, and impeller diameter. However, Njs depends directly on particle size, while Nmin depends instead on interfacial tension and the other physical properties that determine drop size. Skelland and Seksaria (1978) determined the minimum speed to form a liquid-liquid dispersion from two settled (separated) phases of different density and included the sensitivity to impeller location. The vessels used were fully baffled. They determined Nmin for systems of equal volumes of light and heavy phase. Studies included use of single impellers placed midway in the dense phase (C = H/4), at the o/w interface (C = H/2) and midway in the lighter phase (C = 3H/4). They also examined the use of dual impellers located midway in both phases. Several impeller types were tested, including a propeller (Prop), a 45° pitched blade tmbine (PBT), a flat-blade turbine (FBT), and a curved-blade turbine (CBT). Their results are correlated by the following equation, which is dimensionless ... 

When a nematic liquid crystal is placed in contact with another phase (solid or liquid), a surface bounding the liquid crystal is created. The presence of this surface induces a perturbation of the nematic order close to it (Fig. la). The anisotropic interactions between the molecules located right at the surface - in the surface layer - and the other phase favors certain orientations of the surface molecules. This leads to an orientational distribution of the liquid crystal molecules in the surface layer that is generally different from the bulk nematic order. The orientational order evolves from the one induced by the surface to the one in the bulk in an interfacial region of thickness which is of the order of the nematic coherence length. Just outside the interfacial re-... 

Instead of a gas or air, it is possible to use a second immiscible liquid, usually water or an aqueous solution, to separate particles or cells from the first immiscible liquid. The second immiscible liquid may serve as the collector phase collecting the particles into it (see Raghavan and Fuerstenau (1975)). Alternatively, the solid particles may be pushed to the liquid-liquid interface. Whether the particles are going to be located at the liquid-liquid interface or in the bulk of one of the liquid phases can be determined by relations between the three interfacial tensions ySL ySLz y.ii2 Henry (1984)), where Li and L2 are the two immiscible liquid phases. 

Despite the intensive studies of interfacial and confined water, many aspects of its behavior remain not well studied or even unclear. There are only a few studies of the phase diagram of confined water and of water adsorbed on the surface. Most of these studies are the simulations with very simple smooth surfaces. Clearly, experimental studies and simulations with more realistic surfaces are necessary. Repulsion between hydrophilic surfaces in liquid water gained much less attention than attraction between hydrophobic surfaces. However, this effect may be responsible, for example, for the destruction of some solids in environment with varying humidity. The liquid-liquid transitions of water, confined in various pores, should be studied because of their importance not only in understanding the properties of interfacial water but also aiming to locate these transitions in bulk water. 

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