English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The detonation of a cartridge of a high explosive is started by firing a detonator, which consists of a small metal cylinder containing a compound or mixture which is itself readily detonated when it is heated. The manner in which detonators thus function is not thoroughly understood, and the methods used for measuring their "efficiency" are, in consequence, diverse. By some methods only the total blow given by the detonator, or its crushing and shattering effect, is measured; thenail test andsand test are the crudest forms. Thelead plate test gives a similar measure, and the efficiency of a detonator is judged not only by the depth of the impression produced, but also by the number and appearance of radial grooves in the lead plate produced by the disrupted metal casing. More precise physical methods have been adopted, such as theHopkinson pressure-bar , which gives a measure of the time of action of the impulsive blow. A more logical method of measurement of efficiency would appear to be a examine the ease with which the detonator will set up detonation in a standard explosive or in a series of standard explosives. Such a method is theEsop test , in which measurement is made of the maximum amount of olive or cotton seed oil which can be mixed with picric acid without preventing its detonation by the detonator embedded in the mixture. Of the same type is thegap test , in which the detonator and a standard explosive are separated and the maximum distance is measured at which detonation of the explosive can be established. The efficiency of a detonator is of considerable technical importance. The more rapidly a detonator can set up detonation in a cartridge of explosive the greater will be the proportion of the cartridge which will detonate and the greater therefore will be the efficiency of the explosive, though once detonation is effectively set up it will be independent of the strength of detonator used. The use of an inefficient detonator may result in portions of cartridges remaining undetonated and becoming a source of danger during the subsequent handling of the material that has been blasted. With the desensitized explosives that are used in coal mines the efficiency of the detonator may influence the safety of the explosive from the point of view of its ability to ignite firedamp. The present investigation has been carried out for that reason.

Explosion waves and shock waves Part II—The shock wave and explosion products sent out by blasting detonators