SADT for a powdery chemical

The SADT for a high explosive of the true AC type depends on the induction period of the autocatalytic reaction however, the autocatalytic reaction does not depend, in principle, on the quantity of the high explosive. On the other hand, as will be explained hereafter in the present chapter, the SADT for a powdery chemical of the quasi-AC type depends on the phase transition, the melting however, it does also not depend, in principle, on the quantity of the chemical. 

Procedure to calculate the SADT for a powdery chemical of the quasi-AC type, having an arbitrary shape and an arbitrary size, confined in an arbitrary closed container of the corresponding shape and size, and placed in the atmosphere under isothermal conditions... 

The concrete procedure to calculate the SADT for a powdery chemical of the quasi-AC type, having an arbitrary shape and an arbitrary size, confined in an arbitrary closed container of the corresponding shape and size, and placed in the atmosphere under isothermal conditions, is illustrated in Section 10.3, by taking the procedure to calculate the SADT for LPO, having an arbitrary shape and an arbitrary size, confined in an arbitrary closed container of the corresponding shape and size, and placed in the atmosphere under isothermal conditions, as an example. 

Procedure to calculate the SADT for a powdery chemical of the quasi-AC type 343... 

It is, thus, clear that it is indispensable to assign a due safety margin to the value of SADT calculated for each high explosive of the true AC type tested herein. It is for this reason that it is stated at the final paragraph of Section 9.5 that the upper limit temperature for the safe handling of a high explosive of the true AC type will be a temperature 30 K lower than the SADT calculated herein. Similarly, it is stated in Chapter 10 as well that the upper limit temperature for the safe handling of a powdery chemical of the quasi-AC type will be a temperature 30 K lower than the SADT calculated herein. 

Once the values of the two coefficients, a and b, of Eq. (59) holding for the induction period of the quasi-autocatalytic reaction of 2 cm of a powdery chemical of the quasi-AC type confined in the closed cell and subjected to the isothermal storage test are fixed, it becomes possible to calculate, for the chemical, in the same manner as performed for a high explosive of the true AC type, an arbitrary value of T as well as the SADT, corresponding to an arbitrary value of At, i.e., an arbitrary exposure time, such as 1 h, 1 d or 30 d. Such a value of temperature may be useful as the upper limit temperature in temperature control to prevent the chemical from exploding thermally after the corresponding exposure time. 

On the other hand, a chemical which is powdery at room temperature but shows a very small interval between the two peaks of the DTA curve is a powdery chemical of the quasi-AC type, so that the isothermal storage test should be performed for it to calculate the SADT. For instance, the DTA curve of ABCN, or that of AMVN, is a case in point (sec Fig, 9 in Section 3.3),... 

The Tc for a chemical of the TD type, including every gas-permeable oxidatively-heating substance, depends on its shape and size. On the other hand, the SADT for a chemical of the AC t5q)e, including every powdery chemical of the quasi-AC type, does not depend, in principle, on its size or quantity. The difference between the concept of the Tc and that of the SADT is discussed at the end of this chapter. 

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