Oscilloscope/velocity probe measuring

The time interval needed for the detonation wave to travel the pre-determined distance between two probes is measured using built-in cursors of the oscilloscope. The detonation velocity is then calculated as a quotient of the distance between two probes(d) and corresponding time interval (t). Similarly the VOD is... 

Direct measurements of spout voidage have been made by Soviet workers, using the piezoelectric technique mentioned in Section IV,B. Simultaneously with particle-velocity measurements, they recorded the frequency with which the solid particles collided with the piezo-crystal from the number of peaks observed on the oscilloscope per unit time. The local voidage at the probe tip was calculated from these data using the equation... 

The measuring equipment needed for the determination of the detonation velocity using the above described type of probes and oscilloscope is illustrated... 

The other group of methods includes those that are based on the registration of the state originated after the shock wave reflection from a barrier. For instance, the detonation pressure m be determined on the basis of the measurement of a thin metal plate firee-surface velocity. The plate free-surface velocity can be determined using optical methods or the electrocontact type of probes and oscilloscope technique. The methods based on the determination of the shock wave velocity through an inert material, e.g., the Aquarium test, are also included in this group. The time resolution of these methods may be on a nanoseconds scale, and even less than a nanosecond, e.g., w en laser interferometry technique is used. Since the processes in the shock fi-ont occur on a nanosecond scale, the present-day techniques are still inadequate to study the detonation wave shock front. 

The arrival of the shock wave is registered with suitable probes placed at a certain distance from each other and at a definite distance from the explosive charge. The time interval needed for the shock wave to pass the distance between two probes is registered by an electronic counter or an oscilloscope. The shock wave velocity at a measured distance from the explosive charge is calculated as a ratio of distance to time. 

An electric counter or oscilloscope can be used for measuring the time interval needed for the shock wave to pass a known distance between two probes. The advantage of the oscilloscope technique is that it enables simultaneous use of several probes. The same test thus enables determination of the dependence of the shock wave velocity upon the distance from the explosive charge. 

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