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Selected Pyrotechnic Publications of Dr. Takeo Shimizu,
Part 1 (1985 to 1994) from the International Pyrotechnic Seminars
Table of Contents (Part 2)
The Critical Burning of Pyrotechnic
Compositions |
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Introduction:
The author attempts to establish a general theory summarizing
the phenomena related to the chemical reactions occurring inside
pyrotechnic compositions. There are three types of reactions:
smoldering, burning and detonation. In addition, there are several
interesting variations like sparking, flashing [strobing] and
pyrotechnic whistling. These phenomena fall between smoldering
and burning or between burning and explosion and should be referred
to as "critical burning". The theory must include these
phenomena.
From Pyroteknikdagen, 1983 |
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Some
Techniques for Manufacturing Fireworks
(1) Dark Delay Compositions
(2) The Use of Metal Powders
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Introduction:
In recent years I have studied the oxidation and reduction taking
place between various substances in a mixture. I reported on some
of these studies in a paper titled "A Concept of Negative Explosives"
presented in 1986 at the Eleventh International Pyrotechnics Seminar
in Vail, Colorado, USA. In the present paper, I will be presenting
the follow-up work which I have performed under the above title.
The work was carried out using the oxygen value of the mixture to
clarify the burning effects. The oxygen value denotes the excess
(positive) or inadequate (negative) amount of oxygen generated in
grams per 100 grams of mixture during the burn.
The term "dark delay composition" refers to a mixture
which does not form a flame or spark that is visible from a distance.
The effect can be used to prevent the formation of the trail from
a flying firework. It is referred to for short in the following
as "dark composition".
When a metal is used as the component of a mixture, a special effect
is generated. A report is given here on metal sparks, red lead explosive
charges and water flares. The metals in question are magnesium,
magnalium, aluminum, ferrotitanium and zirconium, whose effects
are explained as a function of the properties of the metal, those
of the oxygen carrier and the oxygen value of the mixture. From
XVth International Pyrotechnics Congress held in Teneriffe,
Canary Islands (Spain) 8 - 11 Nov. 1989 |
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Research
on the Most Appropriate Method for the Pyrotechnic Industry To
Determine the Sensitivity of Compositions A Concept and the Use
of Negative Explosives |
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Summary: Those of us who work
in the pyrotechnic industry have three requirements to obtain data
concerning the sensitivity of mixtures: establish the starting point
of no-ignition; understand the possibility of propagation of the
ignition to combustion or explosion; clarify the variation of the
sensitivity, which is dependent on the materials that we have used
for tools. The methods used up to now have not satisfied our requirements.
The sensitivity was determined with a drop test using a steel ball
onto a sample placed on an anvil. The sample used was molded as
a thin round disk. This method was used to establish the propagation
of ignition.
Initially, the experiment was conducted using the up-and-down method
so as to compare with that described below. The data obtained on
a salute composition did not indicate a normal probability distribution.
This method does not give an exact result, without having some prior
test data.
The experiment was then conducted using the descending-method, which
I use regularly at the factory. The height of no-ignition was determined
on 50 trials with the salute composition and with the composition
CuO-Al.
It was possible determine the influence of the material of the anvil
on the sensitivity of the mixture and substituting aluminum for
the steel. From EuroPyro 93, 5e
Congrès International de Pyrotechnie du Groupe de
Travail, 6-11 June, 1993 |
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Study
on the Reaction Mechanism of Black Powder And Its Applications
Ballistics of Firework Shells |
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Abstract: Black Powder
is said to be the oldest explosive. At present, it is one of the
most important explosives. However, the burning reaction mechanism
of materials in the mixture is still obscure. The purpose of this
study is to clarify this mechanism and illustrate some applications
of Black Powder.
The burning reaction of Black Powder has been denoted for a long
time by various formulae that include potassium carbonate or sulfate,
which is found in the ash. The author has endeavored to clarify
the formation of such materials during burning, in an effort to
shed light on the burning reaction mechanism.
Through his experiments, the author found that potassium carbonate
or sulfate is formed not only in the case of Black Powder, but also
in the case of mixtures of potassium nitrate and charcoal or potassium
nitrate and sulfur. It is clear that the formation of potassium
carbonate or sulfate is not peculiar to Black Powder, but to nitrate.
The ash contains both of these substances. The formation reaction
takes place not in a gaseous, but rather in a solid or liquid state.
Such a reaction would explain the excellent ignition characteristics
of Black Powder.
Other applications of the burning reaction mechanism of Black Powder
could be found to make ignition of other compounds more effective.
From 26th International Annual Conference
on Pyrotechnics, 1995 |
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Information: Number of pages = 14. |
Detection
of Underwater Blasting Using Electrical Noise |
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Abstract: We conducted a small-scale
experiment on soil simulating underwater blasting and studied the
shape of waves as well as properties of electrical noises generated
during blasting. From these noise waves, we wanted to detect any
failure in initiation of the charge or blasting conditions, etc.
It was observed that the main source of noise is the residual electricity
in the exploder; the shape of noise waves is typical of blasting
conditions of the charge. It enables us to detect blasting failure,
or blasting of detonator touching the water, or detonation of charge,
etc. from these noise waveforms. It was also confirmed that this
method of detection can also be applied in double-hole or multi-hole
blasting which follows stage explosion. From
Journal of the Industrial Explosives Society, Japan, Vol.
39 (1), 1978 |
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