Four phase system

The enzyme catalysed epoxidation of alpha-olefins like 1-octene with oxygen to the optically active epoxide provides an interesting example of a four-phase system (de Bont et al., 1983). The hold-up of the organic phase may be 2-4 % and the presence of biosurface active agents leads to the creation of a large liquid-liquid interfacial area the liquid droplet size becomes smaller than the gas-liquid diffusion film thickness. 

Fig. 1.2 Model of a four-phase system consisting of two liquid phases (e.g., an aqueous and an organic phase) in equilibrium with a gas phase and a solid phase. 

Environmental Data Sets Processed by the NCTR Four-Phase System... 

The NCTR Four-Phase system was recentiy applied to two environmental data sets recognized by EPA as representative subsets of potential EDCs ... 

Table 13.5 summarizes the priority setting results for the two data sets using the NCTR Four-Phase system. When only the Phase I and II protocols are used, the system dramatically reduced the number of potential estrogens by some 80 to 85%, demonstrating its effectiveness in eliminating these most unlikely ER binders from further expensive experimentation. The Phase III CoMFA model further reduces the data size by about 5 to 10%. More importantly, the quantitative binding affinity prediction from Phase III provides an important rank-order value for priority setting. 

Three components with four phases.—system for which three independent components are divided among four phases is also a monovariant system. As, for example ... 

By combining eqs. (5.19)-(5.21) the microhardness for the two-component, four-phase system can be rewritten in the following form ... 

By means of the microhardness additivity law (eq. (4.3)) one can attempt to evaluate the contribution of the soft-segment amorphous phase to the overall micro-hardness. For a four-phase system as in the present case (Fig. 6.7), (two crystalline modifications and two amorphous phases), eq. (4.3) can be written as ... 

An example of this behaviour is found in the five component, four phase system ... 

Many theories have been advanced concerning the mechanisms involved in surfacing the mineral particles so as to create a hydrophobic hydrocarbon film on the mineral surface, and many investigations have been carried out to define these mechanisms. When firoth flotation is used in an aqueous medium that carries the solids to be separated (together with dispersed air bubbles and possibly an organic liquid) a three- or possibly a four-phase system must be considered. In most froth flotation processes, the solid particles are initially completely water-wetted, and the solid-liquid interface must be replaced by... 

Excluded from consideration is the voluminous body of literature concerning heterogeneous reactions in three-phase and four-phase systems (vapor, liquid, solid, condensation nuclei), which particularly interest the atmospheric physicist. Also excluded are surface phenomena other than those referring specifically to an advancing ice surface. 

The process design and the reaction parameters in the Haifa Chemicals process were selected to reduce the limitations imposed by the properties of the extractant. Due to the low efficiency of the extractant, completion of acid extraction from the separated reaction mother liquor is impractical. To avoid losses of reagent and of by-product, the reaction is performed in the presence of the extractant, forming an invariant system. The acidity of the aqueous phase is maintained constant throughout the extraction at a level that provides suitable extraction. The four-phase system (solid KNO, solid KCl, an aqueous solution, and an extractant phase) is, however, difficult to control, a fact that interferes with production of large, easy to wash KNO j crystals. 

Improvement cycle—a four-phase system for quality improvement plan, observe and analyze,... 

Solid-substrate fermentation processes (SSF) are four-phase systems, where air flows through a solid bed containing a water-insoluble support and a nutrient-rich aqueous solution. This technology is used to produce many high-value metabolites, such as antibiotics, biopesticides, aromas and enzymes. 

The theory of this four-phase system (hydrophilic gel phase, lipophilic gel phase, filling water phase and disperse inner phase) generally applies to o/w creams prepared with ionic or nonionic emulsifiers and to stearate creams [3]. 

The Lurgi gas cleanup system, shown in Figures 2, 3, and 4, is a good example of the problems involved. Each of the five counter-current exchangers represents a series of complicated, simultaneous equilibrium and heat transfer calculations for a polar mixture, with a three- and possibly four-phase system. (If the solid fines are considered, the system is four, possibly five phases but the solid phase, which most likely stays with the tar, is generally neglected.) Neither the available enthalpy data, nor the available equilibrium correlations, are really adequate for such mixtures, and the problems would be worse if the pressures were higher, as they may be in the future. This is not to say that... 

The following discussion of infrared ER spectrometry is carried out using a theoretical framework of the three-phase system consisting of air/film/substrate. The substrate should have a polished fiat surface on the film side and a coarse surface on the other side. Otherwise, the system would have to be dealt with as a four-phase system consisting of air/film/substrate/air, which is totally different from a three-phase system. 

A quantitative thermal method, based on the differential of heat capacity signal from modulated temperature differential scanning calorimetry, was described for determining the weight fraction of interface and the extent of phase separation in polymer materials. The interface was modelled as discrete fractions, each with its own characteristic increment of heat capacity. The materials used to demonstrate the range of the method were PS blended with poly(phenylene oxide) (PPO), pure PS, pure PPO, a styrene-isoprene-styrene triblock copolymer (SIS), SIS blended with PPO, PMMA/poly(vinyl acetate) blends and PVC sandwiched with poly(n-butyl acrylate). Two-phase and four-phase systems were used. The calculated results agreed well with experimental results for two- and four-phase systems. 20 refs. 

In some cases, one may wish to describe the interfacial region between bulk substrate and bulk electrolyte by more than just one (homogeneous) phase 2. For example, an adsorbate layer will change to some extent the optical properties of the substrate surface. As a consequence, the three-phase system of Figure 9 should be replaced by a four-phase system, with two thin films sandwiched between the bulk phases. In order to get an idea about the contributions to R/R of the various films in a multilayer system, the linear approximation theory has been expanded. It can be shown that the total AR// of such a system is given by the sum over all R/R values due to each thin layer. For d = X dj A, Eq. (29a) becomes ... 

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