The Three Phases

Phase 1, which is strategy building, sets the direction, providing a vision for the future and a structure for implementation. The process for Phase 1 will have similar deliverables, tailored to the situation, for each sphere under examination. Chapter 12 describes these tasks in some detail. The end product of Phase 1 is a conceptual design. The conceptual design is essentially a justification document. It is in sufficient detail to understand what will be implemented and the costs and benefits of implementation. This will vary from organization to organization. 

In Phase 2, detail design and parallel pilot implementation proceed concurrently. It is at this point that detail documentation, which can be substantial, is prepared. Concurrently, solutions are tested in actual application. At this time, we recommend implementing changes in the organization structure to support the new supply chain design. 

Phase 2 should usually be implemented within the current systems and facility infrastructure. If either or both of these are to change, then the specifications for each must be prepared to support the process design that is developed and tested in Phase 2. Phase 3, full-scale implementation, continues the work begun in Phase 2. Added to it will be scheduled implementation 

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Fig. X-16. (a) Microscopic appearance of the three-phase contact region, (b) Wetting meniscus against a vertical plate showing the meniscus only, adsorbed film only, and joined profile. (From Ref. 226 with permission. Copyright 1980 American Chemical Society.)...

In practice, it may be possible with care to float somewhat larger particles than those corresponding to the theoretical maximum. As illustrated in Fig. XIII-7, if the particle has an irregular shape, it will tend to float such that the three-phase contact occurs at an asperity since the particle would have to be depressed considerably for the line of contact to advance further. The resistance to rounding a sharp edge has been investigated by Mason and co-workers [62]. 

Figure A2.5.31. Calculated TIT, 0 2 phase diagram in the vicmity of the tricritical point for binary mixtures of ethane n = 2) witii a higher hydrocarbon of contmuous n. The system is in a sealed tube at fixed tricritical density and composition. The tricritical point is at the confluence of the four lines. Because of the fixing of the density and the composition, the system does not pass tiirough critical end points if the critical end-point lines were shown, the three-phase region would be larger. An experiment increasing the temperature in a closed tube would be represented by a vertical line on this diagram. Reproduced from [40], figure 8, by pennission of the American Institute of Physics.

Fig. 7. The concept of contact angle with a captive bubble in an aqueous medium, adhering to a hydrophobic sofld P is the three-phase contact point. Here, the vector passes through P and forms a tangent to the curved surface of the air bubble. The contact angle 0 is drawn into the Hquid.

Properties. Thallium is grayish white, heavy, and soft. When freshly cut, it has a metallic luster that quickly dulls to a bluish gray tinge like that of lead. A heavy oxide cmst forms on the metal surface when in contact with air for several days. The metal has a close-packed hexagonal lattice below 230°C, at which point it is transformed to a body-centered cubic lattice. At high pressures, thallium transforms to a face-centered cubic form. The triple point between the three phases is at 110°C and 3000 MPa (30 kbar). The physical properties of thallium are summarized in Table 1. 

Roll-up. The principal means by which oily soil is removed is probably roU-up. The appHcable theory is simply the theory of wetting. In briefest outline, a droplet of oily soil attached to the substrate forms at equiUbrium a definite contact angle at the oil-sohd-air boundary line. This contact angle (Fig. 4) is the result of the interaction of interfacial forces in the three phase boundaries of the system. These interfacial forces, expressed in mN/m(= dyn/cm), or interfacial free energy values expressed in mj/m (erg/cm s) are conveniently designated 1SA iSlj subscripts relate to the Hquid-air,... 

The three-phase region of D2—DT—T2 has been studied (12). Relative volatilities for the isotopic system deuterium—deuterium tritide—tritium have been found (13) to be 5—6% below the values predicted for ideal mixtures. 

The final factor influencing the stabiHty of these three-phase emulsions is probably the most important one. Small changes in emulsifier concentration lead to drastic changes in the amounts of the three phases. As an example, consider the points A to C in Figure 16. At point A, with 2% emulsifier, 49% water, and 49% aqueous phase, 50% oil and 50% aqueous phase are the only phases present. At point B the emulsifier concentration has been increased to 4%. Now the oil phase constitutes 47% of the total and the aqueous phase is reduced to 29% the remaining 24% is a Hquid crystalline phase. The importance of these numbers is best perceived by a calculation of thickness of the protective layer of the emulsifier (point A) and of the Hquid crystal (point B). The added surfactant, which at 2% would add a protective film of only 0.07 p.m to emulsion droplets of 5 p.m if all of it were adsorbed, has now been transformed to 24% of a viscous phase. This phase would form a very viscous film 0.85 p.m thick. The protective coating is more than 10 times thicker than one from the surfactant alone because the thick viscous film contains only 7% emulsifier the rest is 75% water and 18% oil. At point C, the aqueous phase has now disappeared, and the entire emulsion consists of 42.3% oil and 57.5% Hquid crystalline phase. The stabilizing phase is now the principal part of the emulsion. 

Entrained Sohds Bubble Columns with the Sohd Fluidized by Bubble Action The three-phase mixture flows through the vessel and is separated downstream. Used in preference to fluidized beds when catalyst particles are veiy fine or subject to disintegration in process. 

The six secondary phases are obtained by shorting the centre points of each of the three-phase windings of a 3p transformer secondary. 

It is observed that the insulation resistance of one phase with the other two phases grounded is approximately twice that of the entire winding. Therefore, when the three phases are tested separately. the observed alue of the resistance of each phase is divided by two to obtain the actual insulation resistance. 

Now The negalive sequence voltage is caused by an unbalance in the magnitude of voltages in the three phases, rather than in the phase angle. 

Therefore, the level of phase-to-phase asymmetrical faults will he generally of the same order as the three-phase symmetrical faults. The ground faults, however, will he higher than the symmetrical faults. Special care therefore needs he taken while grounding a generator, when they are solidly grounded, particularly to limit the ground fault currents See also Section 20.10.1. 

It is permissible to lest just one panel of a multi panel-assembly so long as the construction of other panels is similar and busbar arrangement and supports are the same. The value of the prospective short-circuit current may be determined from a calibrated oscillogram. The test current in any phase should not vary by more than 10% of the average in the three phases and must be applied for a predetermined time of I or. 1 seconds. Unless specified otherwise, this should be considered as to be I second. 

In this case, all the three phases would be balanced and the residual voltage, Ve, will be zero. The three voltage phasors in the open della windings will be as illustrated in Figure 15.5(a). The phasor sum of these phasors is zero. Therefore W,. = 0. 

These are protection CTs and are used for ground leakage protection. They are also a form of summation CTs, where the phasor sum of the three phase currents is measured. The phasor difference, if any, is the measure of a ground leakage in the circuit. They are discussed in Section 21.5. 

Z( = zero phase sequence or residual impedance. This is measured between the three-phase terminals of a star winding shorted together and the neutral (Figure 20.9(b)) and is calculated by... 

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