Archive for February 2007

SEM Studies on a Strobe Star Composition

R. I. Grose*, M. Cartwright and A. Bailey

ABSTRACT: Data obtained from an analysis of an extinguished strobe star using the technique of scanning electron microscopy (SEM) is used to provide additional evidence for a previous model for the cyclic burning process seen in a white strobe star composition. The model relies on the generation of hot liquid on the surface of the star to initiate the burning process.

Keywords: strobe star, scanning electron microscopy (SEM), hot liquid model


Ref: JPyro, Issue 4, 1996, pp1-4
(J4_1)
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Review: Fire Protective Clothing: A Guide for Those Who Manufacture or Store Pyrotechnics or Propellants

Fire Protective Clothing
EIG 1995

Review by John Bergman

This relatively short publication (23 pages, including references) provides an enlightening look at protective clothing and the various materials— Though a substantial part of the content relates specifically to British and European standards and regulations which readers in other parts of the world may not find directly relevant, there is still much of potential interest.

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Ref: JPyro, Issue 9, 1999, pp67-67
(J09_67)
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Review: Butterworth’s Theatre of Fire

Theater of Fire
Philip Butterworth

Review by Monona Rossol

As a safety expert, I fell in love with this book before I finished the introduction. Author Philip Butterworth introduces his subject with a discussion of the difference in safety-consciousness between the Middle Ages and today. This is appropriate if readers are to appreciate the boisterous and hazardous theatrical pyrotechnic experimentation in this historical period. The author surveyed five major renaissance and medieval data bases for information on period pyrotechnics:

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Ref: JPyro, Issue 9, 1999, pp65-67
(J09_65)
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Bullet Impact Sensitivity Testing of Class B Fwks. Ingredients & Detonability Testing of Flash Powders

J. Edmund Hay

Introduction: The Treasury Department’s Bureau of Alcohol, Tobacco and Firearms (BATF) requested the Bureau of Mines to perform bullet impact sensitivity tests on a selection of class B (display) fireworks shells and some ingredients thereof (flash powder, “stars”), and also to establish that the flash powder used in salute shells is a detonable material, something which is widely presumed but apparently not documented. The fireworks and ingredients to be tested were procured by BATF from two different domestic suppliers and included a variety of foreign as well as domestic shells, two different flash powder compositions, and two different kinds of “stars.” Suppliers of the shells and ingredients are designated in this report as Manufacturer K and Manufacturer M.

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Ref: JPyro, Issue 2, 1995, pp36-43
(J2_36)


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Introductory Chemistry for Pyrotechnists, Part 2: The Effects of Electrons

Wesley D. Smith

ABSTRACT: This is the second in a series of tutorials that introduce the concepts of chemistry to practicing pyrotechnists. The behavior of electrons in atoms is given as the fundamental explanation for all pyrotechnic processes. The periodic arrangement of the elements in a table and their tendencies to unite in chemical bonds are attributed to electrons. Even the production of heat, light, sound, and color in fireworks are ascribed to electronic movements.

Keywords: chemistry, electrons, periodic table, chemical bonds, oxidation, reduction, colored flames.


Ref: JPyro, Issue 2, 1995, pp15-21
(J2_15)
Note: There is an erratum for this article - please Click Here to download
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Hazardous Chemical Combinations

Clive Jennings-White and Ken Kosanke

ABSTRACT: All pyrotechnic compositions present some hazard due to their ability to produce energy. However, some compositions may pose an added hazard because of the combination of incompatible materials. The use of such compositions may result in more frequent accidental ignitions during processing or spontaneous ignitions during storage. Other compositions pose an added hazard because of their ability to produce especially large amounts of energy with rapid reaction rates. The use of such compositions is likely to result in especially powerful explosions in the event of an accidental ignition. This article attempts an organized examination of some combinations of commonly used pyrotechnic chemicals, which are believed to have significantly increased hazard potentials.

Keywords: accidental ignition, spontaneous ignition, hazardous combinations, chemicals, compatibility, incompatibility.


Ref: JPyro, Issue 2, 1995, pp22-35
(J2_22)
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Modern Rack and Mortar Designs for Professional Fireworks Displays

Marc A. Williams

ABSTRACT: Professional fireworks displays, as well as those performed by volunteers, have for many years relied on equipment designs and techniques that were established before the turn of the century. The use of steel mortars, the hand firing of individual aerial shells and the use of wooden racks for chain firing of finale effects have until recently been the industry standard. These techniques and designs are adequate for the use intended, as long as the shells function normally, but if a color shell "detonates" or a salute explodes in a mortar, the results can be catastrophic. Since these designs and techniques first came about, the severity of the legal repercussions from accidents at displays has increased to the point where such an event, however unlikely, now represents an unacceptable legal risk to the display company. In this article, designs are presented for finale racks and single shot mortars (for use in "dense-pack" style rack systems) that were developed at Night Musick Inc., and which significantly reduce the risk of catastrophic equipment failure in the event of a shell malfunction.

Keywords: overpressure, shell detonation, dense pack, finale rack, matrix rack, chain fusing


Ref: JPyro, Issue 2, 1995, pp7-14
(J2_7)
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The Semiconductor Bridge (SCB) Igniter

R. W. Bickes, Jr. and M. C. Grubelich

ABSTRACT: We have developed a silicon semiconductor bridge (SCB) igniter which, when driven with a low-energy current pulse, produces a plasma discharge that ignites energetic materials. Our experiments have demonstrated that SCB explosive devices function in a few tens of microseconds at one-tenth the input energy of hot-wire devices. Despite the low input energies for ignition, tests have demonstrated SCB devices to be explosively safe, passing electrostatic discharge (ESD) requirements and no-fire current levels. In fact, SCB devices can have better no-fire characteristics than hot-wire devices, because of the intimate bridge contact between the underlying thermally conductive substrate. We have tested several different prototype explosive devices. In addition, we have tested SCB actuators with breadboarded "smart" firing sets that will fire the SCB actuators only after transmission of a digital code, after a preset delay, or in a preprogrammed sequence.

Keywords: semiconductor bridge, SCB, pyrotechnic igniter, explosives


Ref: JPyro, Issue 2, 1995, pp1-5
(J2_1)
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Ammonium Perchlorate Composite Basics

Randall R. Sobczak

ABSTRACT: This article addresses the theory and design of ammonium perchlorate/hydroxyl-terminated polybutadiene (AP/HTPB) composite propellant rocket motors. A discussion of the operating principles of solid motors, including motor dynamics, the combustion process of AP composite propellants, and basic nozzle theory is presented. Several grain geometries and thrust profiles are illustrated, and requirements for various casing, nozzle and adhesive materials are compared. The propellant system itself, consisting of oxidizer, binder and fuels, plasticizers, bonding agents and burn rate modifiers, is described.

Keywords: composite propellant, ammonium perchlorate, AP, specific impulse, grain geometry, HTPB, hydroxyl-terminated polybutadiene, nozzle expansion ratio, chamber pressure


Ref: JPyro, Issue 3, 1996, pp35-45
(J3_35)
Note: There is an erratum for this article - please Click Here to download
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