Up and Down Intervals

2 Up and down intervals the intervals in the fall height with the same distance and the same logarithm distance. 

When the results are analyzed after the trials with the up and down method, it becomes problematical to make the intervals of the fall heights the same size or to make the logarithms of integrals of the fall height the same. Professor Dixon et al. described that, in the case of sensitivity data for explosive substances, the distribution of the probability of explosion becomes closer to a normal distribution when the logarithm of the fall height is used rather than the fall height itself. In the up and down method, the analysis is done under the supposition that the distribution of explosion probability is a normal distribution. 

The standard deviation ( o ) of a normal distribution is also presumed for trials for the 50% explosion height (Hs ) with the up and down method. The 1/6 explosion height can be estimated using these two values. Accordingly it seems better to use the up and down method to find the 1/6 explosion height. 

3 Sample settling influences of direct impact, indirect impact and the roller used for indirect impact 

Methods A to E are drop hammer tests and F to I are drop ball tests. The order of amounts of energy necessary for explosion to occur is  

---

The next problem is to determine an adequate up and down interval.Dixon indicated that the interval near a is adequate and should be in the range of 0.5-2.0 o 2 n. The impact sensitivity of the sport paper caps had a narrow deviation range, and it was observed that the distribution was nearer to a normal logarithmic distribution. However, common explosive substances do not always behave this way. Figure 3.12 shows an example. 

---