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Titles and Abstracts for Issue 19, Summer 2004
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Metal
Monochloride Emitters in Pyrotechnic Flames - Ions or Neutrals? |
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Barry Sturman 6
Corowa Court, Mount Waverley, Victoria 3149, Australia |
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Abstract: Twelve English-language
books on pyrotechnics were surveyed for the authors' views on the
nature of the metal monochlorides that are associated with the emission
of colored light in pyrotechnic flames. Three of the ten authors
stated that the emitters were metal chloride ions (MCl+),
five that they were neutral metal chloride molecules (MCl), and
two took no clear position. A study of the references cited in these
books establishes that the emitters are neutral monochlorides. The
idea that they are MCl+ ions is traced to a book published
in 1965, which cited only one reference (published in 1949), and
that reference clearly stated that the emitters are neutral molecules.
Keywords: colored flame, emitter,
spectra, monochloride, ion, neutral
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Experimenting with High Explosive Fuel Explosions
for Movies and Television |
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Stephen Miller Live
Action FX Ltd, 152 Ayelands, New Ash Green, Longfield, Kent DA3 8JU
UK |
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Abstract: A number of 'brute
force' techniques used within the special effects industry utilise
high explosives to create the classic 'Hollywood' style fuel explosion
seen in many a movie and television programme. Limited experiments
have shown that application of techniques similar to those used
in shaped charge anti-tank weapons (the Munroe effect) can produce
higher and larger fuel explosion effects, while using less fuel
and explosive material, thereby creating a more controlled effect.
Keywords: high explosive, fuel
explosion, special effects, directional shaped charge, Munroe effect,
compression tube
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Industrial
Scale Nano-Aluminum Powder Manufacturing |
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David Pesiri, Christopher E. Aumann, Luke
Bilger, David Booth, R. Doug Carpenter, Rob Dye, Edward O'Neill, Debbie
Shelton, and Kevin C. Walter
Technanogy Materials Development, 2221 Cape Cod Way, Santa Ana, CA
92703 USA |
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Abstract: Producing nano-aluminum
powder (n-Al) on a commercial scale places a great deal of emphasis
on practical manufacturing issues. Scientists and engineers in the
laboratory commonly evaluate nano-aluminum powder in the technical
terms of its particle size, particle size distribution (PSD), morphology
and oxide shell thickness. The quality of nano-aluminum at the commercial
scale, however, rests upon several additional parameters that emphasize
manufacturing effectiveness (production rate, process reproducibility,
raw material utilization, lot size and scalability) as well as product
quality (powder purity, surface properties and extent of agglomeration).
Balancing the practical demands of a commercially viable process
with the technical needs of specialized end users has been the challenge
throughout the life of Technanogy Materials Development (TMD). Today
TMD stands as a company focused on the manufacture and commercialization
of nano-aluminum powder and able to assist others in developing
nano-aluminum applications. The issues and insights related to the
scale-up of this technology during the past three years are described.
The properties of nano-aluminum powder that have motivated this
scale-up are also discussed.
Keywords: nano-aluminum, nanoparticle,
particle size distribution, passivation, oxide layer thickness,
nanomaterial
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Essential
Molecular Orbital Theory for the Study of Pyrotechnics |
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R. B. Lowry
School of Earth, Ocean and Environmental Sciences, Univ. of Plymouth,
Drake Circus, Plymouth PL4 8AA UK |
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Abstract: The Linear Combination
of Atomic Orbitals (LCAO) model is presented as it applies to small
heterogeneous molecules. A non-mathematical approach is used to
enable the discussion of the terminology used. The production of
light and the rules that govern it are examined.
Keywords: linear combination
of atomic orbitals, LCAO, energy level, electronic transitions,
color, molecular orbital theory
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Guanidinium
Azo-Tetrazolate (GAT) as a High Performance Hybrid Rocket Fuel Additive
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M. Keith Hudson,* Ann M. Wright,‡ Chris
Luchini,* Paul C. Wynne,* and Sterling Rooke*
*Department of Applied Science and Graduate Institute of Technology
University of Arkansas at Little Rock, Little Rock, AR 72204, USA
‡ Department of Physics, Hendrix College, Conway, AR 72032, USA |
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Abstract: The purpose of this investigation
was to find a high regression rate fuel suitable for use as a mixture
with hydroxyl-terminated polybutadiene (HTPB). Guanidinium azo-tetrazolate
(GAT) is the compound that was the focus of our research. GAT is a
salt containing a high percentage of nitrogen. It has two conjugated
nitrogen rings, which are negatively charged, and a positively charged
component consisting of nitrogen, carbon, and hydrogen. In addition
to the high-energy content of this compound, as a salt, it has a lower
heat of degradation due to the ease of breaking its ionic bonds.
GAT was found to react with N100, a common curative for HTPB. An
alternative isocyanate curative was found, polyisocyanate (PAPI),
with which it did not react. This polymer matrix was found to be
suitable for GAT. The resulting fuel grains were difficult to cast
due to the rapid polymerization of the HTPB/PAPI. Once grains were
cast, they required no special care in storage or firing.
The fuel grains with the GAT additive were fired for 3-second
runs with oxygen flows of 0.04, 0.06, 0.08, 0.10 and 0.12 lbm/s.
The regression rate of each GAT concentration was computed and plotted
vs. the oxidizer mass flux on a log/log scale. The resultant curve
is fit to the equation, ,
and the quantities a and b were recorded for each curve.
GAT was found to increase the regression rate of HTPB when it
was used as an additive. The resultant pressure and thrust from
firing even the highest GAT concentrations at high oxygen flows
still remained within safe operating parameters of the UALR hybrid
rocket motor facility.
Keywords: GAT, guanidinium
azo-tetrazolate, GZT, HTPB, hybrid rocket fuel, ground testing,
regression rate
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A
Report on the Fireworks Accident at Carmel, Western Australia |
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R. I. Grose+ and K. L. Kosanke*
+ Defence Science and Technology Laboratory,
Porton Down, Salisbury, Wiltshire, SP4 0JQ, UK * PyroLabs, Inc., 1775
Blair Road, Whitewater, CO 81527, USA |
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Abstract: The investigation
into an accident at Carmel, Western Australia in March 2002 found
that the magnitude of explosions occurring in licensed and unlicensed
storage areas was significantly greater than would have been expected
from the UN hazard classification of items stored within them. Use
of revised UN default classification tables for the items in storage,
instead of the previous classification, goes towards accounting
for the violence of the explosions. The official report into the
accident makes a number of recommendations that are of direct international
relevance, such as a minimum safety distance of 400 m (from residential
housing or defined vulnerable facilities) for licensed UN Hazard
Division 1.1 magazines regardless of mass of contents (above 50
kg minimum), removal of a concession that allows for the temporary
storage of fireworks in unlicensed areas for up to 14 days prior
to a display, the adoption of the UN default classification table
throughout Western Australia and the importation of incorrectly
classified fireworks to be made an offence.
Keywords: Carmel explosion,
UN hazard classification, safety distance, unlicensed storage
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Illuminants
and Illuminant Research |
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David R. Dillehay 107
Ashwood Terrace, Marshall, Texas 75672 USA |
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Abstract: The use of pyrotechnic
compositions for the production of light has a long history. Most
improvements were made mainly by trial and error with many misunderstandings
about the cause and effect relationships from observations. Significant
advancements in the mechanisms and theory of combustion have increased
the understanding of many effects and led to improved illuminants
both theoretically and practically. Radiative transfer theory explained
most of the observed variations in illuminant functioning. Effects
of spin, liner thickness and binders have been analyzed, and application
of the results has been used to improve illuminant performance and
solve production problems.
Keywords: illuminant, photoflash,
efficiency, magnesium, sodium, nitrate, binder, radiative transfer
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Bandwidth
in Electro-Magnetic Compatibility (EMC) Testing |
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James Stuart Franklin
Applied Physics, 98 Highland Avenue, PO Box 313, Oaks, PA, 19456 USA
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Abstract: Electro explosive
devices (EEDs) are often required to undergo a test in which they
are placed near a high-power radio transmitter. The purpose is to
see whether electromagnetic energy might fire the EED. Consideration
of the "Q" or quality factor of an EED system affords guidance in
choosing a transmitter and test procedure. This can lead to shorter,
simpler tests, and to improved efficiency in electromagnetic-exposure
tests of all kinds.
Keywords: bandwidth, EED, electro
explosive device, EMC test, electro-magnetic compatibility test,
HERO test, irradiation test, quality factor
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A
Brief Description of the Construction and Function of Common Electric
Matches |
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Lawrence Weinman Schneier/Weinman
Consultants, LLC, Huntsville, AL USA and
K. L. Kosanke PyroLabs, Inc., Whitewater,
CO USA |
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Abstract: A simple description
of the construction and the physical principles governing the function
of common electric matches and some implications of these principles
for testing and firing them are presented.
Keywords: electric match, heat
resistance, current, volt, pyrogen
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Communications
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Comment from Ron Lancaster on
"Review of Pyrotechnics" in Issue 18
Review by K. L. Kosanke of Ignition
Handbook by Vytenis Babrauskas
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