R. Meyer J. Köhler A. Homburg Explosives

291 Specific Energy
grain (Bernoulli’s equation), by W Erosive Burning, by the igniter system,
and by irregular combustion of the remaining propellant. The
thrust-time diagram (W Thrust, Thrust Determination) can be derived
from the pressure-time diagram obtained from equation (4).
Spacing
Bohrlochabstand; distance entre trous
The distance between boreholes measured parallel to the free face
toward which rock is expected to move.
Spark Detonators
Spaltzünder; amorce électrique à l’étincelle
Spark detonators, like bridgewire detonators, were employed in the
past to produce electric initiation of explosive charges. The priming
charge itself, containing current conducting additives, served as a
current conductor through the priming pill itself. Relatively high voltages
were required to produce the ignition, so that such devices were
safe from stray currents.
Spark detonators have now been substituted by W Bridgewire Detonators.
If there is danger of stray currents, low-sensitivity primer types
are employed, which can be actuated only by a strong current pulse.
Special Effects
These are special arrangements for the simulation of dangerous
events in the military, western, and science fiction scene in motion
pictures and television programmes.
Frequently, specially designed fireworks are used for creating these
effects, e.g. tiny detonators (W Bullet Hit Squib) for the simulation of
bullet impacts.*)
Specific Energy
spezifische Energie; force
The specific energy of an explosive is defined as its working performance
per kg, calculated theoretically from the equation of state for
ideal gases:
* Clark, Frank F., Special Effects in Motion Pictures, Society of Motion Picture
and Television Engineers, Inc., 862 Scarsdale Avenue, Scarsdale, N.Y. 10583,
Second Printing 1979.