Temperature diagrams

In addition to the three principal polymorphs of siUca, three high pressure phases have been prepared keatite [17679-64-0] coesite, and stishovite. The pressure—temperature diagram in Figure 5 shows the approximate stabiUty relationships of coesite, quart2, tridymite, and cristobaUte. A number of other phases, eg, siUca O, siUca X, sihcaUte, and a cubic form derived from the mineral melanophlogite, have been identified (9), along with a stmcturaHy unique fibrous form, siUca W. 

Fig. 5. Pressure—temperature diagram for the more familiar Si02 polymorphs (43). To convert MPa to atm, divide by 0.101.

Pressure—temperature diagrams for the coesite—quart2 equilibrium have been summari2ed (23). Coesite has been found ia nature ia the meteor crater ia Ari2ona. 

Eig. 1. Schematic pressure—temperature diagram for a pure material showing the supercritical fluid region, where is the pure component critical point... 

Fig. 3. Schematic flow and temperature diagram of the multistage flash (MSF) process for a recirculation type plant.

Figure 2-33. Energy/temperature diagram of the tripie pressure HRSG.

Figure 12-70. Entropy-temperature diagrams help to solve compression work problems. Data for ammonia provided. (Used by permission Corrigan, T. E. and A. F. Johnson. Chemical Engineering, V. 61, No. 1, 1954. McGraw-Hill, Inc. All rights reserved.)...

Free Energy - Temperature Diagrams (Ellingham Diagrams)... 

Fig. 16. Gibbs energy-temperature diagram if FCC and ECC are present in the system. Ai-isotropic (undeformed) melt, A2-deformed melt (nematic phase) points 1 and 4 - melting temperatures of FCC and ECC under unconstrained conditions (transition into isotropic melt) points V and 2 -melting temperatures of FCC and ECC under isometric conditions (transition into nematic phase), point 3 - melting temperature of nematic phase (transition into isotropic melt but not completely randomized)...

It is supposed that water is to be cooled at a mass rate L per unit area from a temperature 0L2 to Ql - The air will be assumed to have a temperature 6G, a humidity Jf ], and an enthalpy Hoi (which can be calculated from the temperature and humidity), at the inlet point at the bottom of the tower, and its mass flow per unit area will be taken as G. The change in the condition of the liquid and gas phases will now be followed on an enthalpy-temperature diagram (Figure 13.16). The enthalpy-temperature curve PQ for saturated air is plotted either using calculated data or from the humidity chart (Figure 13.4). The region below this line relates to unsaturated air and the region above it to supersaturated air. If it is assumed that the air in contact with the liquid surface... 

Hence on an enthalpy-temperature diagram, the operaling line of slope 1.33 is drawn through the point... 

On an enthalpy temperature diagram (Figure 13.20) the enthalpy of saturated gas is plotted against its temperature. If equilibrium between the liquid and gas exists at the interface, this curve PQ represents the relation between gas enthalpy and temperature at the interface H/ v. 0/). The modified enthalpy of saturated gas is then plotted against temperature (curve RS) to give the relation between H f and Of. Since b is greater than unity. RS will lie below PQ. By combining equations 13.35. 13.70, and 13.72, H[ is obtained in terms of Ha-... 

Wood, B. and Beds, P. Engineer 189 (1950) (4912) 337, (49131 349. A total heat-temperature diagram for cooling tower calculations. 

Figure 1.89. Activity of 82(052 )-temperature diagram showing possible as and temperature ranges for epithermal Au disseminated-type (hot spring type), epithermal Au-Ag vein-type and epithermal base metal vein-type deposits in Japan (Shikazono 1986 Shikazono and Shimizu, 1988b).

From (1-79) it is clear that the Hg content of electrum is related to /sj and A l-vg. Using the thermochemical data for reaction (1-78) by Barton and Skinner (1979), isoactivity lines for Hg in electrum may be drawn on a log/sj-temperature diagram (Fig. 1.175). At a given temperature, the activity of Hg in electrum increases with a decrease in /sj. Therefore, the /sj for the mercurian gold of the Tsugu deposit is inferred to be relatively low. 

Figure 1.175. Activity of S2-temperature diagram showing iso-Hg contents contours for gold. The calculations were carried out using thermochemical data of Craig and Barton (1973).

Iso-FeS content lines for sphalerite in equilibrium with pyrite or pyrrhotite were drawn on the log/sj-temperature diagram (Figs. 1.179 and 1.180) using thermochemical data by Scott and Bames (1971) and Barton and Skinner (1979). 

A standard free energy versus temperature diagram for oxides is often presented with a scale for oxygen pressures. Such a diagram is shown in Figure 3.6. This scale is designed to... 

Figure 3.6 Free energy-temperature diagram with scales showing oxygen pressures, C0/C02 and H2/H20 pressure gas ratios.

Lc 1 nm or Lc>20 nm). Highly graphitic materials (<7002 within 0.335 -0.338 nm and Lc>30 nm) show some increase of the capacity when the lowest limit of d002 is achieved and Lc increases. The specific reversible capacity vs crystallite size or vs treatment temperature diagrams are often published. They look as smooth curves with a minimum within medium temperatures or medium crystallite sizes [7,11,17]. 

The answer to question (2) raised above is more easily seen if we translate Figure 14.5 into an enthalpy-temperature diagram, and then consider the stationary-states as those resulting from balancing the rate of enthalpy generation by reaction with the rate of enthalpy removal by flow (we are still considering adiabatic operation for an exothermic reaction). 

Figure 14.7 Representation of multiple stationary-states on an enthalpy-temperature diagram corresponding to (b) in Figure 14.5...

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