bluuebunny/crossref_metadata_2025_split huggingface dataset:
A temperature‐profile Study of the Combustion of Black Powder and its constituent binary mixtures
Authors: Brown M. E. , Rugunanan R. A. 
Published: December 2004

AbstractAn earlier thermo‐analytical study of black powder, using small sample masses and slow heating rates, has been extended to an examination of the behaviour of black powder under the less‐controlled conditions of ignition and combustion, by simultaneous measurement of temperature profiles and burning rates.Burning‐rate against composition curves for various charcoal/KNO3, mixtures (sulphurless black powder) and for charcoal/KNO3, mixtures with various proportions of sulphur, were concave‐down‐type curves. The compositions of mixtures with maximum burning rates did not correspond with the compositions of mixtures with maximum enthalpy‐of‐reaction. Maximum temperatures of ∼1400°C were recorded. Burning rates were found to decrease with increasing particle size of the constituents: with increasing compaction of the mixtures, or when inert diluents or subsidiary fuels were added to the mixtures. Burning rates were also affected by moisture contents above 276, and failure of burning occurred at >15% moisture.
Explosives Research at Cerchar
Authors: Bigourd J. , Michot C. 
Published: December 2004

AbstractFrom the very beginning. the Centre d'Etudes et Recherches de Charbonnages dc France (CERCHAR) has devoted part of its activity to explosive products. In the period from 1950 to 1970, this work was concerned only with the use of these products in coal mines, the main purpose being to reduce the risk of firedamp and coal dust ignition. For about the past fifteen years, CERCHAR's activities have also concerned:

the use of explosive products in mines other than coal mines, and in quarries. as regulations have often to bc adapted to new products and new techniques,
the general safety (manufacture, transport, storage and use) of explosive products for civil use, this work being generally directed towards a better appreciation of the risks involved.
This paper reviews the principal results of this research and outlines the studies now in progress.
A Study of molybdenum/barium chromate/potassium perchlorate delay system(1)
Authors: Rajendran A. G. , Ramachandran C. , Babu V. V. 
Published: December 2004

AbstractThe effect of percentage variation of Mo and KClO4 on Mo‐BaCrO4‐KClO4 delay system has been studied. The reaction sequence has been investigated by means of thermo‐gravimetry (TG): differential thermal analysis (DTA) and X‐ray diffraction studies. KClO4 is found to be essential to start the reaction, but its decomposition is not the rate determining step. Up to 20% of KClO4 leads to enhanced burning rate, while excess had the opposite effect. Mo in excess of stoichiometry increases the reaction rate which seems to depend on thermal conductivity rather than on the heat of reaction. DTA of the tricomponent system shows two exotherms. The first one is due to the reaction between Mo and KClO4 releasing enough heat to start the second reaction between Mo and BaCrO4. Then the products of these reactions viz. BaO and MoO3 combine to give BaMoO4. X‐ray diffraction data confirmed the products as BaMoO4, Cr2O4 and KCl, with excess Mo remaining unreacted.
Relationship between brisance of explosives and their molecular‐atomic structures
Authors: Eremenko L. T. , Nesterenko D. A. 
Published: December 2004

AbstractThe explosives with various molecular‐atomic structures substantially differ by their detonation velocities and brisance but often are similar by the expansion of their detonation products (DP's) which mainly consist of the same molecules. Such explosives referred to as “usual” show the relationship between ϱD and brisance determined by different methods. There are linear correlation relations between the results obtained.This relationship is not observed with the “unusual” explosives which differ from the “usual” ones by the chemistry of detonation processes. These explosives include liquid explosives, explosive‐oxidants. CNO‐ and HNO‐explosives and also CHNOF‐explosives. Their calculation of thc detonation parameters and brisance from the same criterions which characterize the chemical composition of the explosives and the detonation products, results in some errors.Taking these differences into account it is possible in some cases markedly to increase the accuracy of the detonation parameters. As an example is the calculation of the detonation pressure to within 3% based on the linear correlation relation between the pressure (PJ) and the relative detonation impulse (Irel) which characterizes the charge ability to do work at the initial stages of thc expansion of the detonation products:

The relative impulse, in its turn, may be calculated both for “usual” and “unusual” explosives from the atomic composition of an explosive, its density and the enthalpy of the formation with the error that does not exceed the experimental (2%).
Thermal Decomposition of Energetic Materials. 42. Fast thermal decomposition of five N‐Methyl substituted ethanediammonium dinitrate salts
Authors: Russell T. P. , Brill T. B. 
Published: December 2004

AbstractThe fast thermolysis of N‐methyl substituted ethanediam‐monium dinitrate salts is described by temperature profiling/FTIR spectroscopy. The salts described are [CH3NH2CH2CH2NH3](NO3)2 (MEDD), [CH3NH2CH2CH2NH2CH3](NO3)2 (SDMEDD), [(CH3)2NHCH2CH2NH3](NO3)2 (UDMEDD), [(CH3)2NHCH2CH2NH2CH3](NO3)2 (TRMEDD) und [(CH3)2NHCH2CH2NH(CH3)2](NO3)2 (TMEDD). MEDD, UDMEDD, SDMEDD and TRMEDD more closely resemble the behavior of alkylammonium mononitrate salts than primary alkanediammonium dinitrates in terms of the temperature at which HNO3 is released. However, TMEDD resembles the dinitrates. Both C‐C and C‐N bond fission occur based on the nature of the alkylamine products that are liberated.
Combustion of Black Powder. Part IV: Effect of carbon and other parameters
Authors: Hussain Ghulam , Rees Gwilym J. 
Published: December 2004

AbstractThermo‐analytical techniques such as DSC, TGDTG have been used to study the ternary mixtures of KNO3, S and charcoal/carbon black. S exists in two forms, one is called free sulphur on the surface of grains, while the other is termed adsorbed or trapped S. The first form of S, is removed between 175°C to 300°C while the second form is removed around 375°C. The ratio of two forms is altered by the grain and nature of carbon. Carbon black, as compared to charcoal, produces more energy from the oxidation of carbon. The effect of heating rate and the way the sample is placed, is also observed.
The stability characterization of the pyrotechnic system. The degradation of the nitrate oxidant in the presence of the magnesium under the accelerated aging conditions
Authors: Batinic‐Haberle Ines , Barisin Dubravka , Spasojevic Ivan , Vranic Zoran 
Published: December 2004

AbstractThe degradation of the nitrate oxidant was followed in the course of the aging process of tracer pyrotechnic mix containing 22.0 % Mg, 46.0 % Sr(NO3)2, 22.0 % KCIO4, 9.0 % Al‐Mg alloy and 4.0 % organic binder. The accelerated aging was conducted under the conditions of the increased humidity (98.5 %, 85.0 %, 78.5 %) at the increased temperature (75 °C). Nitrate content as a function of aging time was calculated by substracting nitrite nitrogen from total nitrogen content determined by Devarda's alloy reduction method. The degradation products of the nitrate (nitrite and carbonate) were determined by UV/VlS (Griess reaction) and IR spectroscopy, respectively. Nitrate proved to have a great instability in the presence of the metal, the extent of its conversion to nitrite and carbonate being rather great in comparision to the previously studied alkali metal nitrates in the presence of Mg as well. The loss of the nitrate and the formation of the nitrite and carbonate are governed by the same kinetic laws as fuel degradation to the hydroxide. The rate of the metal oxidation to the hydroxide was faster than the rate of the nitrate degradation process. The failure of the mix is connected to the rather small content of the nitrite (0.4 %) while the texture was significantly destroyed.
Combustion of Boron‐Based Slurries in a Ramburner
Authors: Liehmann W. 
Published: December 2004

AbstractIn a combustion chamber equipped with windows, boron and boron alloy slurries were burnt. The fraction of the solids in these mixtures was 25%. For the quantitive analysis of the reaction products, three spectrometer systems were used: an optical multichannel analyzer for the range 0.2 μm to 0.9 μm, an acusto‐optical tunable IR‐filter for the range 1.2 μm ‐ 2.4 μm, and rotating IR‐filters covering the range from 2.5 μm to 14.5 μm. The determination of the gas‐phase temperature of the exhaust plume was obtained by evaluation of the OH rotation bands. The particle temperature was measured with a fast two‐color pyrometer. During the burning process of boron with an average particle size of 2 μm, only a weak background radiation was detected. Mg and AlB2, produced a greater amount of particles in the exhaust due to their particle size of about 50 μm.The spectra of the exhaust plume show typical bands for the particular metals and the combustion products of the JET Al fuel. Particle size distribution, surface characteristics, and temperature are important parameters for the ignition and combustion of solids. Also, the flow field inside the combustion chamber influences the burning behaviour of the solid particles. Therefore the slurries were injected against the main flow direction to produce high turbulence.
Developement of neutral polymeric bonding agents for propellants with polar composites filled with organic nitramine crystals
Authors: Kim C. Sue , Youn H. , Noble Paul N. , Gao Andrew 
Published: December 2004

AbstractVersatile neutral polymeric bonding agents (NBPA's) have been developed for energetic propellants in which polar HMX particles are dispersed in a polar binder matrix containing highly polar plasticizers (TMETN, NG, etc.). Using a semi‐empirical approach through adjustment of solubility parameters and molecular weight, neutral acrylonitrile interpolymers were synthesized which mix uniformly with the submix and still have a high affinity for the HMX particles when they are added. Addition of about 0.2 % w/w of NPBA to HMX‐filled PEG binders increases the strength by a factor of as high as five compared to samples with no NPBA, and also eliminates the sudden decrease in modulus (knee) which occurs at relatively low elongation. The degree of filler reinforcement achieved by our NPBA's in energetic propellants is far superior to that achieved by adding nitrocellulose or any other previously proposed bonding agents, and similar to the effect of precoating the HMX particles with polyurea shells.
The importance of jet tip velocity for the performance of shaped charges against explosive reactive armor
Authors: Held Manfred , Schwartz Wolfgang 
Published: December 2004

AbstractIt is shown, that the portion of a shaped charge jet that emerges from explosive reactive armor is longer or at least less disturbed if the jet tip velocity can be raised. Generally, the residual jet length largely depends on the ratio of the reaction time of the armor and the standoff of the shaped charge from the armor.
Kinetic Deuterium Isotope Effects in the combustion of formulated nitramine propellants
Authors: Trulove Paul C. , Chapman Robert D. , Shackelford Scott A. 
Published: December 2004

AbstractThe kinetic deuterium isotope effect was used to investigate the rate‐limiting process in the combustion of formulated nitramine propellants. Model propellant formulations containing either octahydro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine (HMX), hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine (RDX), or their deuteriated analogues were pressed into pellets and burned under nitrogen pressure in a window bomb. The magnitudes of the observed deuterium isotope effects indicate that the HMX and RDX exert significant control over the combustion phenomenon of the propellants studied. Furthermore, assuming a consistent mechanism between decomposition and combustion, the observed isotope effects suggest that a carbon‐hydrogen bond rupture in HMX or RDX is the rate‐controlling step in the combustion of the model nitramine propellants. Observed isotope effect values for HMX‐CW5 and RDX‐CW5 formulated propellants at 1000 psig (6.99 MPa) pressure were 1.29 ± 0.09 and 1.24 ± 0.07, respectively, compared to a theoretical estimate of 1.29 for a primary effect due to CH bond rupture at 673 K.
Stabilizer reactions in cast double base rocket propellants. Part V: Prediction of propellant safe life
Authors: Sammour M. H. 
Published: December 2004

AbstractPropellant deterioration can be kinetically analysed by both Berthelot's law and Arrhenius' law. Kinetic analysis of the mixed stabilizer para‐nitro‐N‐Methylaniline(pNMA)/2‐nitrodiphenylamine (2NDPA) based propellant deterioration at different temperatures, during the time necessary for the complete consumption of the more reactive stabilizer pNMA, which can be taken as a measure of the safe life of these propellant compositions, gave results for both Berthelot's law and the Arrhenius' law which are satisfactory. However, it was found that the predicted safe life for the propellant compositions according to the Arrhenius law was much longer than that obtained from Berthelot's law. Therefore, from the safety point of view, it is preferable to use Berthelot's law analysis to assess the safe life of double base propellant compositions.
Analysis of Strains, Strain Rates and Temperatures during the early stages of shaped charge liner collapse
Authors: Zernow Louis , Chapyak Edward J. 
Published: December 2004

AbstractIn trying to understand the extraordinarily high dynamic ductility of a copper shaped charge jet, prior work by the authors has utilized the Eulerian MESA 2D code with a novel form of the LaGrangean tracer particle technique as well as the experimental “soft recovery” and metallurgical examination of partially collapsed copper liners.This work had indicated that localized material processing occurs during the earliest stages of liner collapse and causes dramatic visible grain size refinement, evident in the photomicrographs. Further computational analysis shows that the localized plastic flow is accompanied by very high localized engineering strains (>200), extremely high (>4 × 107 s−1) localized strain rates, as well as elevated temperatures, all of which favor a dynamic recrystallization process.In this paper, the focus is on a detailed quantitative analysis of strain, strain rate and temperature distribution history within the collapsing liner, in the region of the inner liner apex and the early location of the moving collision zone, where the early material conditioning first occurs. Correlations are sought between the computed, time‐dependent values of these three paremeters and the microstructures observed in the interiors of the partially collapsed liners, in those regions where the grain size changes are observed. This data may ultimately permit quantitative comparisons with the predictions of dynamic recrystallization models.
Determination of the Thermal Diffusivity of a Zr/PbCrO4 Pyrotechnical Mixture and of the arrhenius parameters of the ignition reaction in presence of an oxidizing atmosphere
Authors: Marlin F. , Roux M. , Brassy C. , Espagnacq A. 
Published: December 2004

AbstractAn experimental device with main features closely related to those of Cook‐Off type(1) devices has been developed to attain the specific study requirements. The tested product is a pyrotechnical compound containing zirconium and lead chromate in the proportion of 60% Zr and 40% PbCrO4.An iterative calculation method has been developed to determine thermal diffusivity without any reaction and to evaluate the Arrhenius kinetic parameters of the product ignition reaction.The Zr/PbCrO4 compounds appear as cylindrical tablets dia. 14 mm and 11.7 mm high. From room temperature to about 100°C, thermal diffusivity ranges between 3.2 and 3.9. 107 m2/s. The ignition reaction kinetic parameters in an oxidizing atmosphere are as follows: Ea = 47 kJ/mol and Z = 10 · s−1. With the results from thermal analysis, we demonstrate that initiation can be attributed to the oxygen contained in air, which diffuses into the product porosities. Lead chromate behaves as an inert substance throughout the ignition phase.
Application of Crystal Lattice Disintegration Criteria to Compute Minimum Shock induced reactive conditions in solid explosives and inert materials
Authors: Billingsley James P. , Adams Carl L. 
Published: December 2004

AbstractA threshold particle velocity criteria derived by E.R. Fitzgerald for the beginning of crystal lattice breakup and disintegration has been applied to shocked explosives and an inert material. In shocked explosives, reactions leading to detonation occur above a certain “threshold” magnitude. The computed crystal lattice breakup shock pressures compare rather well with observed experimental “threshold” shock pressures for six high explosives. The six explosives are: Comp‐B3, Comp‐B, TNT, PBX‐9404, Tetryl, and H‐6.In addition, the crystal lattice breakup criteria provides an explanation for the observed lowering of the detonation “threshold” shock pressure as the explosives are made more porous or less dense.Finally, the shock pressures, at which output from thermocouples embedded in shocked materials (PBX‐9404 and Plexiglass) increases dramatically, compare favorably with predictions based on crystal lattice disintegration criteria.Consequently, it is tentatively concluded that crystal lattice breakup, or self‐sustained phonon fission as Fitzgerald calls it, is responsible for the initiation of detonation in shocked explosives and enhanced thermocouple output in shocked materials. It is also postulated that the lattice breakup phenomena is also responsible for phase changes, increased chemical reactivity, and anomalous electrical activity which are observed in certain inert materials under relatively low level shock loading.
Ignition mechanism of the Zr/PbCrO4 pyrotechnic mixture in presence of an oxidizing atmosphere
Authors: Brassy C. , Marlin F. , Roux M. 
Published: December 2004

AbstractIn presence of oxygen, the Zr/PbCrO4 (60%/40%) solid mixture exhibits a high amplitude exothermal reaction at low temperature (before reaching the oxidant decomposition temperature). We assume that the reaction is entertained by the air oxygen which continuously diffuses into the mixture pores.The solid‐phase diffusion of oxygen through a zircon layer seems to constitute the limiting step of the reaction. To verify this assumption, a model allowing for diffusion in a protective oxide is developed. The results obtained with this model correspond to the tests for an apparent energy diffusion value varying between 130 kJ/mol and 170 kJ/mol. A value of 130 kJ/mol corresponds to the migration energy of the anionic gaps in a porous zircon layer. The evolution of the apparent diffusion energy can be attributed to the formation energy of crystalline defects (in particular anionic gaps).
Flame Atomic Absorption Spectrometric Determination of lead and titanium in samples of double‐base propellants
Authors: Baqir Sadiq J. , Jasim Fadhil 
Published: December 2004

AbstractThis research demonstrates how additives such as Pb(II) and Ti(IV) in powders of double‐base propellants (D‐BP) could be analysed by flame atomic absorption spectrometry (F‐AAS). No separation or preconcentration is needed. Both direct and spiked techniques have been applied successfully. The use of synthetic (simulated) D‐BP calibration standards is advocated for the analysis of real (D‐BP) samples. The effects of diverse ions and matrix modifiers are investigated. Sensitivity, detection limit, linearity, RSD% and recovery percent are calculated. It is foreseen that this analysis is suited to further application in other additives (usually present in D‐BP) e.g., nickel, cobalt, zinc, manganese, calcium and iron.
The Solubility of ϵ‐CL‐20 in Selected Materials
Authors: von Holtz Erica , Ornellas Donald , Foltz M. Frances , Clarkson Jack E. 
Published: December 2004

AbstractThe solubility of the epsilon polymorph of CL‐20 was determined in thirteen liquids over the temperature range of ambient to 74°C using high performance liquid chromatography. The experiments included ϵ‐CL‐20 produced by two different synthesis routes; one lot contained a higher level of polymorphic impurity, the other lot contained a higher level of non‐CL‐20 impurity.In general, the ϵ‐CL‐20 was found to be highly soluble in the solvents with carbonyl groups, and relatively insoluble in hydrocarbons and materials containing ether linkages. The amount of phase conversion to γ‐CL‐20 which occured during the solubility testing was measured using FTIR, and ranged from essentially zero to ∼ 10% conversion. It appears that the presence of β‐CL‐20 in the virgin ϵ‐CL‐20 lots will affect the amount of gamma‐phase present in the final residue.
Influence of Longitudinal Gaps on the Detonation Front
Authors: Held Manfred 
Published: December 2004

AbstractPrecursor air shocks with velocities that are 50 % higher than the velocity of detonation occur not only in cylindrical holes, but also in flat slits. By attaching to the test charge a sufficiently long plexiglass body with the same hole or slit profiles it is possible to observe the end face of the test charge and, thus, to record the changes in the detonation profile caused by slits, in particular by such that are oblique to the direction of detonation. One result is, that there is no through‐detonation across thin slits that are at a flat angle to the detonation wave.