Books – Shimizu Articles

Detection of Underwater Blasting Using Electrical Noise

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.


Ref: Selected Pyrotechnic Publication of Dr. Takeo Shimizu, Part 2,  pp 59-68
(Sh2_59)
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Study on the Reaction Mechanism of Black Powder And Its Applications Ballistics of Firework Shells

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.


Ref: Selected Pyrotechnic Publication of Dr. Takeo Shimizu, Part 2,  pp 45-58
(Sh2_45)
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Some Techniques for Manufacturing Fireworks (1) Dark Delay Compositions, (2) The Use of Metal Powders

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[1] 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.


Ref: Selected Pyrotechnic Publication of Dr. Takeo Shimizu, Part 2,  pp 21-38
(Sh2_21)
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Research on the Most Appropriate Method for the Pyrotechnic Industry To Determine the Sensitivity of Compositions

SUMMARY:  Those of us who work in the pyrotechnic industry have three requirements to obtain data concerning the sensitivity of mixtures:

1) establish the starting point of no-ignition

2) understand the possibility of propagation of the ignition to combustion or explosion

3) 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.


Ref: Selected Pyrotechnic Publication of Dr. Takeo Shimizu, Part 2,  pp 39-45
(Sh2_39)
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The Critical Burning of Pyrotechnic Compositions

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.


Ref: Selected Pyrotechnic Publication of Dr. Takeo Shimizu, Part 2,  pp 1-21
(Sh2_1)
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Part VII. On Composition Series for Practical Use

ABSTRACT:

(1) The spectroscopic studies in the previous Parts are summarized so as to apply the principle of flame color creation for practical use.

(2) According to the results of (1), various samples of red, yellow, green and blue of several composition series are prepared. Their flame colors are examined by the naked eye and good colors are selected. According to these, effective color zones are written as enclosed areas in triangle graphs.

(3) As far as these studies are concerned the important results that seem to be common for each series are as follows:

a) The width of an effective composition zone in a graph is very narrow for low temperature flames and fairly wide for high temperature flames.

b) Ammonium perchlorate is the best oxidizer, for it can produce HCl in a flame and creates deep color.

c) Polyvinyl chloride is also the best additional ingredient that can create a deep color by producing HCl gas in the flame like ammonium perchlorate. d) It is necessary to completely protect compositions from moisture for high temperature flames to prevent the magnesium and other ingredients from reacting with each other. For practical applications deep and brilliant color flames are obtained only in accord with this consideration.


Ref: Selected Pyrotechnic Publication of Dr. Takeo Shimizu, Part 3,  pp 107-119
(Sh3_107)
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Part VI. Flame Spectra of Metal Aluminum Compositione

ABSTRACT: The previous Parts showed the effect of magnesium powder as a fuel in high temperature compositions. In this Part the effect of aluminum powder is examined. In general aluminum melts and is sprayed as sparks out of the flame. It is not as easily vaporized because of its high boiling point. With aluminum the intensity of the spectrum of color-producing bands is not as high as with magnesium.


Ref: Selected Pyrotechnic Publication of Dr. Takeo Shimizu, Part 3,  pp 103-105
(Sh3_103)
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Part V: Flame Spectra of Blue Color Compositions

ABSTRACT: We can see three different flame colors (i.e., blue, light green and reddish orange) when we insert a small copper piece into a flame of a burner. The blue color is caused by CuCl bands with the strongest lines between 4269–4560 Å. Our goal is to use this color for fireworks. Blue is produced by some copper salts or copper metal powder in the presence of chlorine or hydrogen chloride gas, but if the concentration of gas is small, the blue color is interfered with by the light green color, which seems to be caused by a continuous spectrum of other copper chloride bands (5263–5531 Å).

The flame spectra are examined under various conditions. For low temperature flames, ammonium perchlorate is the best oxidizer and produces an excellent bright blue. For high temperature flames it is necessary to decrease the percentage of magnesium powder, because the CuCl bands seem to  dissociate with increasing magnesium.


Ref: Selected Pyrotechnic Publication of Dr. Takeo Shimizu, Part 3,  pp 87-102
(Sh3_87)
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Part IV. Flame Spectra of Red, Yellow and Green Color Compositions

ABSTRACT: lame spectra of red, yellow and green color  compositions are examined under various conditions.

a. Red Flame

A red flame is produced by bands from strontium (Sr) salts. These bands consist of five main bands [i.e.,  (6013), (6203),  (6300),  (6428) and (6558)], where each number represents the wavelength of the maximum intensity in Angstroms (Å). The influence of chlorine on the  band is quite different from theothers, namely the  band is weakened by chlorine, whereas chlorine intensified the others, and this effect is greater with hydrogen chloride gas than with chlorine gas. This is very clearly observed especially in low temperature flames. The influence of strontium salts is very small. The effect of oxidizers that produce either chlorine or hydrogen chloride gas is quite remarkable. If we add ingredients that have chlorine, they can intensify each band only in high temperature flames. The effects of calcium (Ca) salts were also examined.

b. Yellow Flame

A yellow flame is produced by sodium (Na) salts. The spectrum consists of mainly Na-D lines, but in addition, a continuous spectrum from Na atoms appears between 5,800 and 6,100 Å and makes the flame color rather white, especially at high flame temperatures.

c. Green Flame

Only BaCl bands can produce green flames when barium (Ba) salts are used as the color agents. Compositions without chlorine cannot produce green color because only BaO bands appear, giving white color to the flames. In the presence of chlorine both BaCl and BaO bands appear. The effect of chlorine or hydrogen chloride gas in a flame seem to weaken the BaO bands and to intensify the BaCl bands. The effect of chlorine gas is less than that of hydrogen chloride gas. And so, ammonium perchlorate produces a better green color than potassium perchlorate. Adding some kind of chlorine compound (chlorine donor) is also effective to intensify the green color.


Ref: Selected Pyrotechnic Publication of Dr. Takeo Shimizu, Part 3,  pp 57-86
(Sh3_57)
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Part III. On Backgrounds of Color Flame Spectra

ABSTRACT: Blank runs were made with nominal colorproducing compositions to investigate the lines, bands or continuous spectra that appear as background and interfere with the desired spectra of red, yellow, green, etc. These sample compositions consisted of solid materials such as oxidizers (ammonium perchlorate, potassium chlorate, potassium perchlorate, potassium nitrate, etc.), low temperature fuels (shellac, rosin, pine root pitch, etc.), and magnesium powder for the high temperature fuel.

For low flame temperatures sodium D (Na-D) lines (5890 and 5896 Å, caused by impurities contained mainly in the oxidizers), continuous spectra (caused by carbon particles and potassium atoms) and potassium (K) lines (5802, 5783, 5832, 5813; 5340, 5324, 5360, 5343; 5090, 5084, 5113, 5080; 4044, 4048 Å) are observed. For high flame temperatures Na-D lines are also observed, and in addition to the above, MgO bands and continuous spectra (the latter are caused by solid metal oxide particles and K atoms) are found.

The main interfering spectra are the Na-D lines and continuous spectra. Purification of ingredients is very important to remove Na-D lines and to obtain fine colored flames. For high flame temperatures, the addition of chlorine- containing compounds such as polyvinyl chloride, ammonium chloride, etc. to a composition is effective in decreasing the intensity of the continuous spectra, and it is assumed that the metal oxide of the solid phase is converted into the metal chloride of the vapor phase in the presence of chlorine or hydrogen chloride in the flame, but this should be ascertained by further experiments of higher accuracy. The addition of shellac is also effective in weakening the intensity of the continuous spectra and decreasing the black body temperature of the flame.

The permeability coefficients and black body temperature of flames of basic compositions are measured for reference .


Ref: Selected Pyrotechnic Publication of Dr. Takeo Shimizu, Part 3,  pp 39-56
(Sh3_39)
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