Thermal diagram

Phosphorus Pentabromide, PBr5.—In the presence of excess of bromine phosphorus can form not only the pentabromide 5 but also, according to the thermal diagram, other perbromides.6 It was discovered early 5 that the presence of some iodine greatly facilitates the combination, probably by the formation of IC13, thus —... 

Fig. 5.4. Thermal diagram for Semenov model of thermal explosion the rate of chemical heat release varies with the dimensionless temperature excess 0 according to/(0) = e the rate of heat transfer is given by the straight line with a gradient of l/ifi. For small ifi the loss line is steep and makes two intersections corresponding to two steady-states for large tli the loss line has a low gradient and does not allow steady-state intersection points the critical case corresponds to tangency of the heat release and heat loss lines.

On the other hand, by sacrificing some of the information regarding the composition of the ternary solutions, it is possible to secure a plane diagram which will give the temperature variations of the system. Thus, by projecting perspectively the curves in Fig. 102 and Fig. 104 not on the base of the prism but on one of the faces, say the face BC, of the prism, a poly thermal diagram is obtained which shows the relative proportions of the two components B and C in the different systems. The proportion of the component A in the different systems,... 

The crystallographic data are summarized in Table III. The thermal diagram... 

At one given temperature the composition of, and phase equilibria in, a ternary aqueous solution can be represented on an isothermal triangular diagram. The construction of these diagrams has already been described. Poly-thermal diagrams can also be constructed, but in the case of complex systems the charts tend to become congested and rather difficult to interpret. 

For the effeets of storage time, the tricaprin/tristearin blend 50 50 (w/w) was melted at 80°C for 20 min, and then cooled to 5°C by direct inunersion in a water bath for 10 min, and the sample was inserted inside the NMR spectrometer heated to 40°C. The sample was kept at this temperature for 14 days. For polarized microscopy, the thermal diagram applied to the sample was the same, but the tricaprin/tristearin blend 75 25 (w/w) was used for a matter of clarity. 

Thermal explosion theory effectively begins with Semenov in 1928. He presented his arguments [7] in terms of a "thermal diagram". Such a picture had been employed earlier in France but not interpreted mathe-matically. 

Fig. 65a Grey scale thermal diagram for planetary cooler...

The surface temperature of the cooling tubes is therefore the most important measured variable, which is determined with a radiation pyrometer or by infrared television connected to a mini-computer, so that, besides a grey scale thermal diagram, the temperatures are made directly "visible" and abnormally high temperatures are promptly detected (Figs.65a and 66). 

The thermal diagram offers the most simple representation of the location of and access to stationary states and it paves the way to a description of events as they are commonly observed experimentally. Depicted in Figure 1 are qualitative representations of the way in which the heat-release rate CR] and the heat-loss rate CL3, described by Equations CB] and C7], vary with temperature over a moderate range. The main feature of the heat-release rate is its rise to a maximum and a fall Cin the realm of the ntcr] followed by a further growth as the temperature increases. Clf we were to trace R to very much higher temperatures it would eventually reach a limiting rate determined by the condition oyerall T.] L is a linear function of T and its intersections with R determine the number of singularities that... 

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