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THE DATA TABLES
SHOCK INITIATION PROPERTIES
The data tables indicate the driver-and-attenuator systems used for each experi-
ment. Also given are the LASL shot number; the initial shock pressure, particle
velocity, and shock velocity; a fitting parameter, l/2 b, used in the data reduction
where appropriate; the sample density; the distance to detonation, x*, and time to
detonation, t*.
Usually the U,, - U,, data are plotted. Also given are equations for these data fit-
ted to one of two functional forms, the most common of which is linear. These equa-
tions are given with their coefficients and the standard errors of the coefficients. If
the sound speed has been used as a data point in determining the fit, it also is given.
For a few explosives, a hyperbolic function is fitted to the data and coefficients
without standard errors are given.
For some explosives, a logarithmic function fit to the initiation data, x* or t* vs
P,, is given. Generally, this is done only for the distance to detonation, x*. Usually,
if these fits are given, a “Pop” plot also is included. The “Pop” plot functional form
traditionally has been a power function with x* or t* as dependent variables and P,
as the inde:pendent variable. However, recent work3 suggests that the appropriate
fitting plane should be log-log, because the measurement errors in x* have been
shown to be lognormal, and the t* and P, errors may also be lognormal. Since x* and
t* are measured quantities and P, is based on measurements, all are stochastic
variables, and a statistically valid regression analysis cannot be used to estimate a
functional relationship. Nevertheless, x* and t* physically occur after the imposi-
tion of P,,, and thus it has been argued that they result from (or are dependent on)
P,. Since the error in P, data is generally greater than x* and t* error, in finding an
“average relationship” between them, it is more appropriate to assume that the
variable with the least error is the independent variable.4 For these reasons, the
“Pop” plot functions are given in log form, with log P, being the dependent variable.
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