Third phase

The new concept overcoming this limitation in the third phase of experimental kinetics started around 1950,... 

Many pairs of partially miscible liquids possess neither a lower nor an upper C.S.T. for reasons outlined in the previous paragraph. Thus consider the two liquid phases from the two components water and diethyl ether. Upon cooling the system at constant pressure, a point will be reached when a third phase, ice, will form, thus rendering the production of a lower C.S.T. impossible, likewise, if the temperature of the two layers is raised, the critical point for the ether rich layer will be reached while the two liquid phases have different compositions. Above the critical point the ether-rich layer will be converted into vapour, and hence the system will be convert into a water rich liquid and an ether rich vapour the upper C.S.T. cannot therefore be attained. 

As metal extraction into a diluent—extractant solution proceeds, there is sometimes a tendency for formation of two organic phases in equiHbrium with the aqueous phase. A third phase is highly undesirable and its formation can be prevented by adding to the organic phase a few percent of a modifier which is typically a higher alcohol or tri- -butyl phosphate (TBP) (7). 

If the dmg is not soluble in the propellant, it is dissolved or dispersed in a Hquid vehicle. The propellant then constitutes the third phase of the system, and the container must be shaken before valve actuation. Emulsified aerosol products like lotions and creams are examples of such systems. 

For extraction of uranium from sulfate leach Hquors, alkyl phosphoric acids, alkyl phosphates, and secondary and tertiary alkyl amines are used in an inert diluent such as kerosene. The formation of a third phase is suppressed by addition of modifiers such as long-chain alcohols or neutral phosphate esters. Such compounds also increase the solubihty of the amine salt in the diluent and improve phase separation. 

Phases. Often there are two Hquid phases (Hquid—Hquid PTC) or one soHd, one Hquid (soHd—Hquid PTC). If the catalyst is bound to a polymeric matrix this may comprise a third phase (triphase catalysis). Examples of gas—Hquid, gas—soHd, and soHd—soHd PTC are stiH relatively rare. In the latter two cases, a small amount of Hquid, eg, water, is probably present as an uimoticed third phase. 

The traditional view of emulsion stability (1,2) was concerned with systems of two isotropic, Newtonian Hquids of which one is dispersed in the other in the form of spherical droplets. The stabilization of such a system was achieved by adsorbed amphiphiles, which modify interfacial properties and to some extent the colloidal forces across a thin Hquid film, after the hydrodynamic conditions of the latter had been taken into consideration. However, a large number of emulsions, in fact, contain more than two phases. The importance of the third phase was recognized early (3) and the lUPAC definition of an emulsion included a third phase (4). With this relation in mind, this article deals with two-phase emulsions as an introduction. These systems are useful in discussing the details of formation and destabilization, because of their relative simplicity. The subsequent treatment focuses on three-phase emulsions, outlining three special cases. The presence of the third phase is shown in order to monitor the properties of the emulsion in a significant manner. 

In the case of emulsions with three liquids the presence of the third phase results in a reduction of the energy input for the emulsification process, whereas the emulsion with a Hquid crystal as the third phase shows interesting stabilization mechanisms. Finally, the emulsion with added particles illustrates the importance of Hquid—solid wetting for stabiHty. 

Liquid Third Phase. A third Hquid with coUoidal stmcture has been a known component in emulsions since the 1970s (22) for nonionic surfactants of the poly(ethylene glycol) alkylaryl ether type. It allows low energy emulsification (23) using the strong temperature dependence of the coUoidal association stmctures in the water—surfactant—hydrocarbon systems. 

Liquid Crystal Third Phase. In addition to micelles and microemulsion droplets, surfactants may form Hquid crystals. A Hquid crystal is a separate phase, which comes out of solution, not like the micelles or microemulsion droplets, which are microscopic entities within the solution. 

We may now be on the verge of the third phase of oxirene chemistry in which modern matrix isolation techniques (80CSR1) will permit the spectroscopic observation of this system, theory will serve as a guide to the synthesis of relatively stable oxirenes (c/. a fairly stable... 

Few investigators have considered fireball liftoff time. According to Roberts (1982), a fireball starts liftoff in the third phase of its development, that is, when buoyancy and entrainment are dominant. Hardee and Lee (1978) give the following expression for liftolf time t <, ... 

Characteristic of the microstructure of PET fibers in their final production form is the occurrence of three types of polymer phases crystalline, mesomorphous, and amorphous. The first phase is the result of crystalline aggregation of PET molecules, the second phase—of mesomorphous or, in other words, paracrys-talline aggregation, the third phase—of amorphous aggregation. The mesomorphous and amorphous phases together form a noncrystalline part of the fiber. 

Low Flow Mist Extractor Third Phase Fourth Phase... 

A third phase is sometimes identified in pitting corrosion, i.e. termination. Pits can become stifled by the build-up of insoluble corrosion products at their mouths. Removal of these mounds of corrosion products, either mechanically or through some change in the environmental chemistry, can allow the pits to restart growth. 

Surrounding the earth is the third phase, a gas. The gas mixture surrounding the earth is called the atmosphere. Over 98% of this gas (air) is less than 40 miles above the earth s surface. 

There is an important law referring to such equilibria, which states that if the two phases A and B of a substance, and the two phases A and C are at a given temperature in equilibrium separately, then all three phases will be in equilibrium together at that temperature. Thus if two phases are, at a given temperature, separately in equilibrium with a third phase, they will be in equilibrium with each other. 

Then if any two phases are separately in equilibrium with a third phase, they are also in equilibrium when placed in contact, so that if any one phase (e.y., the vapour) is taken as a test-phase, and the other phases are separately in equilibrium with this, the whole system will be in equilibrium. Under the conditions imposed, it is sufficient that the vapour pressure, or osmotic pressure, of each component has the same value at all the interfaces, for we may consider each component separately by intruding across the interface a diaphragm permeable to that compo- -nent alone. Then if the vapour, or osmotic pressures, are not equal at the third interface to their values at the first and second interfaces, i.e., at the interfaces on the test-phase, we could carry out a reversible isothermal cycle in which any quantity of a specified component is taken from the test-phase to the phase of higher pressure, then across the interface to the phase of lower pressure, and then back to the test-phase. In this cycle, work would be obtained, which however is impossible. Hence the two phases which are separately in equilibrium with the test-phase are also in equilibrium with each other. This may be called the Law of the Mutual Compatibility of Phases (cf. 106). 

In his original demonstration Gibbs (1874) showed that the surface layer may be considered as a third phase having specific values of density, energy, and entropy, and further that the results of the theory are quite independent of the actual extent of the capillary layer and the way in which it merges into the free fluids on either side. As a matter of fact, the transition... 

The third phase of the Arsenal s development began with an appropriation in 1906 of 165,000 for the erection and equipage of a powder factory. This work was undertaken by Major B.W. Dunn, Jr, the inventor of Explosive D , which replaced Maximite for armor-piercing shell. 

During the third phase, the motor chamber continues to fill with propellant combustion products until the steady-state pressure has been reached. The chamber-pressure transient during this phase is described by... 

Consequently, the composite may be considered as consisting of three phases, that is the matrix, the inclusions and a third phase, which is a layer of variable thickness, including all these changes and which surrounds each one of the inclusions. This hybrid phase is called the mesophase. 

A satisfactory model for particulates is a modification of the well-known model proposed by Hashin 1 According to this model the composite consists of three phases the matrix, the inclusion, and a third phase, called the mesophase, which corresponds to the zone of imperfections, surrounding the inclusions2,3). 

If a particulate composite is considered, consisting of a polymeric matrix and an elastic filler, by the previous procedure, the mechanical and thermal properties, as well as the volume fraction of the mesophase can be determined. The mesophase is also expected to exhibit a viscoelastic behaviour. The composite consists, therefore, of three phases, the third phase (the mesophase) being also viscoelastic. The presence... 

The novel element in these models is the introduction of a third phase in the Hashin-Rosen model, which lies between the two main phases (inclusions and matrix) and contributes to the progressive unfolding of the properties of the inclusions to those of the matrix, without discontinuities. Then, these models incoporate all transition properties of a thin boundary-layer of the matrix near the inclusions. Thus, this pseudo-phase characterizes the effectiveness of the bonding between phases and defines a adhesion factor of the composite. 

These models are improvements of a similar model4), where the third phase was assumed with constant mechanical properties, lying in-between the two main-phases and represented in Fig. 13. This model is totally defined by considering as boundary-... 

---