Phase diagram measurements

Broadly speaking, the first application of CALPHAD methods was intrinsically coupled to experimental thermodynamic or phase-diagram measurements. For... 

Figure 23. Experimental values of 1 - T Gasb as a function of xs along several isotherms in the Al-Ga-Sb system. The calculation used the recommended value of ftcasb in Table I and the phase diagram measurements of Dedegkaev et al. (145) ( , 778 K 0, 825 K A, 873 K) and of Cheng and Pearson (182) (O, 773 K , 823 K).

The phase diagram was calculated from the binary boundaries and from the quaternary mixtures measured, therefore the standard deviation of the fit is not given. The calculated phase diagram of this system is shown in Figure 3.53. The experimentally determined phase diagram measured by Chernov and Ermolenko (1973) is probably not quite correct because of little experimental data in the region of the presented peritectic point. 

Fig. 1.1.5 Phase diagram measurement results for the PMAA/water system. The critical point (LCST) is obtained from the literature (Hhassaf and SBbeiberg, 1962). Spinodal decomposition-based points are used to analyze kinetics of phase separation deep inside the spinodal region...

In a first attempt, double distilled water was used as solvent for all surfactant molecules. The obtained schematic phase diagrams for the individual surfactant molecules will be presented in the following. Next to the schematic phase diagram measured while heating, the schematic phase diagram obtained while cooling will be shown whenever monotropic phases appear in the investigated system. 

Fig. 5.10 Schematic phase diagrams measured on heating (top) and cooling (bottom), which were derived from the contact region of C50 and polyethylene glycol 300...

The case studied by the Utrecht groups and mentioned in Section I.l, seems to correspond closely to this situation (see the numerical values after eq. (IV.5)). The phase diagram measured for various molecular weights (but keeping NJN constant) do seem to give a variation of 4 with N which is close to the inverse square-root law of eq. (IV. ). 

Copolymers P(ME02MA-co-OEGMA) flat phase diagram measured Tip were in the range of 28—90 C ... 

Gabriel, A., Peltm, A.D., 1985. Phase diagram measurements and thermodynamic analysis of the PbClj Nad, PbClz-KO, and PbCh-KCl-NaCl systems. Can. J. Chem. 63 (11), 3276-3282. 

The structures of the various lyotropic mesophases mentioned so far have been elucidated over the years primarily using low-angle X-ray diffraction. An X-ray diffraction pattern of a liquid crystal provides information not only on the state of organization of the hydrocarbon chains but also on the crystallographic lattice of the micellar structure. It must be emphasized, however, that often the X-ray method alone cannot define the absolute structure of a liquid crystal phase because too few diffraction lines are observed. In these cases, a knowledge of the position and extent of the mesophase region in the phase diagram, measurements by other techniques (NMR, optical microscopy), and information such as the size, shape and chemical nature of the surfactant are necessary before a reliable identification can be made. 

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