Degree isothermal/nonisothermal

The models discussed thus far were essentially isothermal. Nonisothermal models as described below contain an additional degree of complexity that is always related to the characteristics of a particular reactor and the form of a particular catalyst. On the other hand, it is usually easier to construct a nonisothermal model that oscillates, because the exponential term in the Arrhenius law provides a very strong nonlinearity. Nonisothermal models can be classified into two categories surface blocking/reactivation models and models with additional bulk effects. 

The validity of parameter-sets 6 and 8 should additionally be confirmed by using the data from non-isothermal experiments to reject a further possibility in the existence of other parameter-sets with a good degree of fitting. The nonisothermal transient experiments, unfortunately, have not been conducted within the period giving a constant activity of the catalyst. The mode of the transient response curve of N2 is significantly affected by the value of kj, rather than... 

An accurate study of the temperature profile structure in film and capillary samples involves considerable technical difficulties, which accounts for the lack of direct information on the role of the isothermal and nonisothermal mechanisms in the systems considered. However, some features of the structure are evident from the cinegram of Fig. 9. It shows that the wave front traveling in a capillary is noticeably ahead of the zone of intense reaction-heat release, marked by violent boiling of liquid helium in the cryostat. This observation allows the conclusion that here the fore part of the wave front is located in the not yet heated portion of the sample that is, small degrees of... 

The degree of conversion a is a function a(j5) of a state variable P, which depends on time. For an isothermal reaction, P is taken to be proportional to the time P = kt, with k the reaction rate constant, which is assumed to be time-independent because the temperature is. For a nonisothermal conversion P = kdx (the integral between T = 0 T = as k is exponentially dependent on the temperature T, which is time-dependent. 

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