bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Acoustic Field on the Thermal Conductivity of composite propellants
Authors: Ramachandran Lalitha , Gowariker V. R. 
Published: December 2004

AbstractA study is conducted to determine the effect of acoustic field on the thermal conductivity of composite propellants based on poly‐ butadiene and polyurethane binders. The thermal conductivity of the propellant is determined by a specially designed equipment. The thermal conductivity measurements are made in steady state conditions and in an acoustic field of constant amplitude at various frequencies ranging from 1 kHz to 6 kHz and at different temperatures ranging from 30°C to 50°C. The results indicate that the thermal conductivities of the composite propellants increase when they are subjected to an acoustic field. The data obtained are presented in the paper. Since the burning behaviour of solid propellants is influenced also by its thermal conductivity, the present work may be of direct relevance in improving upon some of the existing burning rate and combustion models.
The Initiation of Tetryl by Small Charges of PETN
Authors: Dinegar R. H. , Millican M. S. 
Published: December 2004

AbstractExplosion times of PETN pressings and PETN/tetryl assemblies have been measured as a function of the length and density of the PETN donor charge and the density of the tetryl acceptor. A charge length of about 3.5 mm is necessary for the PETN explosion wave to reach steady‐state velocity for the densities studied. The initiation of the tetryl pellet is related to the detonation velocity (and presumably peak pressure) as well as the pressure‐distance profile generated in the PETN explosion wave. Higher‐density tetryl charges appear to be more sensitive than lower.
Some theoretical considerations on Improving the Internal Ballistic Performance of Guns
Authors: Melchior E. , Witt W. 
Published: December 2004

AbstractAn improvement in internal ballistic performance is understood to mean an increase in muzzle velocity for the same weight of projectile and the same peak pressure. Using a thermodynamic model of the internal ballistics a possible method of achieving a significant improvement in performance is demonstrated based on optimizing the properties of the propellant in a charge of conventional design. An example of the application of the theoretical results is discussed.
The European Commission for the Standardization of the Tests of Explosives (changed since 1976: International study group for the standardization of the methods of testing explosives)
Authors: Ahrens H. 
Published: December 2004

AbstractSince 1960 a group of experts, gathered on a voluntary basis, are working under the name of “European Commission for the Standardization of the Tests of Explosives” (Europäische Kommission zur Vereinheitlichung der Sprengstoffprüfungen – Commission Européenne de Normalisation des Essais d'Explosifs).The following is a short description of this activity, from its origin, up till now and for the future.
The Effect of Gritty Contamination on the Initiation of Explosives by Impact
Authors: Scullion H. J. , McCormack J. 
Published: December 2004

AbstractIn studies on the Rotter machine on the initiation of grit‐contaminated explosives by impact one can make use of the variable θ = 100 (F−Fmin)/Fmax where F = figure of insensitiveness. A virtually linear relationship then exists between the grit content (C %) and the reciprocal (or logarithm) of θ.
Über die Verwendbarkeit der neuen Methode der Sprengkapselprüfung nach Prior sowie der Prüfzünder PETN als Prüfnormal
Authors: Herrmann R. 
Published: December 2004

AbstractDie von J. Prior vorgetragene Methode zur Sprengkapselprüfung wurde von uns neben der Bleiblockprüfung verwendet.Die Veranlassung dazu war folgende: Der bisher verwendete Trauzl Bleiblock (250 mm hoch) ist umständlich in der Anwendung und für das Bedienungspersonal nicht frei von toxischen Wirkungen. Seine Mängel beim Anzeigeverhalten, die jetzt nach 50 Jahren bekannt sind, waren nur in zweiter Linie ausschlaggebend für einen Wechsel der Prüfmethode. Für das neue Verfahren läßt sich auch erst in 50 Jahren sagen, ob es besser ist. Zunächst hoffen wir es.Die Bedingung für einen Wechsel der Prüfmethode: Eine neue Methode zur Bestimmung des Zündvermögens soll sich möglichst gut an die bisherige Methode anlehnen.Das Ergebnis dieser Untersuchungen: Die von J. Prior vorgetragene Methode erfüllt diese Forderung, so daß wir sie unserer nationalen Behörde als neues Prüfverfahren für Sprengkapseln vorschlagen werden. Die Aussagefähigkeit entspricht der des Bleiblocks. Die Anzahl der jeweils durchzuführenden Versuche muß noch festgelegt werden, um eine gleichwertige Genauigkeit zu erhalten.Als Prüfnormal an Stelle der Normalsprengkapsel Nr. 8 wird der Prüfzünder PETN 0.37 g vorgeschlagen. Auch hier muß die Übereinstimmung noch überprüft werden.
Ways of Reducing the Deflagration Tendency of ion‐exchanged permitted explosives
Authors: Glaskova A. P. , Zhadan S. N. 
Published: December 2004

AbstractThis work considers possible ways of reducing the deflagration tendency of ion‐exchanged permitted explosives based on new experimental data on the inhibition of ignition of methane‐air mixtures and on the cornbustion of condensed systems.The mixtures contained the nitrates or perchlorates of the alkali metals as oxidizers together with ammonium chloride, oxalate, sulphate or phosphate as fuel. They had a zero oxygen balance. The effect of adding 12% of gelatinized nitroglycol was also investigated. The lower pressure limit and the burning rate were chosen as parameters to characterize the deflagration rendency. They were in a constant pressure bomb over the pressure range 0.1 MPa to 100 MPa using a method described previously.It is shown that the lower pressure limit is higher and the burning rare lower for mixtures containing ammonium oxalate than for analogous mixtures but with ammonium chloride. The lower pressure limit is also higher for mixtures based on potassium perchlorate.The calculated explosive characteristics and the burning parameters of the mixtures investigated arc reported. Reasons for the higher deflagration tendency of the mixtures containing ammonium chloride are discussed.
Mach‐Reflection of Detonation Waves in condensed high explosives
Authors: Müller F. 
Published: December 2004

AbstractIn a cylindrical arrangement as deviced by G. R. Fowles and W. M. Isbell for the generation of Mach‐reflection of shock waves in solids Mach‐reflection of detonation waves in condensed high explosives with different detonation velocities is investigated. The process is observed directly by flash x‐ray radiography. By means of this arrangement it is possible to generate via Mach‐reflection a plane detonation wave, the Mach‐disk. Characteristics and applications of the Mach‐disk are discussed.
A Numerical Study of Explosive Heating due to Projectile Impact
Authors: Chawla M. S. , Frey R. B. 
Published: December 2004

AbstractA finite difference Eulerian computer code with some very useful Lagrangian features is employed to study the impact of a projectile on a heavily confined, inert, solid explosive. Temperature rise due to shock compression and plastic deformation in both the explosive and the metal confinement is estimated. It is concluded that in situations where the shock is weak and the explosive does not initiate shortly after the projectile impact, the possibility of it so doing, due to plastic deformation, at a later time cannot be discounted.
The assay of ammonium nitrate and ethylenediamine dinitrate
Authors: Selig W. 
Published: December 2004

AbstractAmmonium nitrate and ethylenediamine dinitrate in a composite have been determined by potentiometric titration with standard base after reaction with formaldehyde. Ethylenediamine dinitrate yields two breaks, while ammonium nitrate exhibits only a single potentiometric break. Both components can therefore be resolved. The first potentiometric break is a measure of the ethylenediamine dinitrate content, while the second break is a measure of the sum of the components.
High‐speed photographic studies of impact on thin layers of emulsion explosive
Authors: Krishna Mohan V. , Field J. E. , Swallowe G. M. 
Published: December 2004

AbstractA photographic study, at microsecond framing rates, has been made of the impact behaviour of thin layer samples of emulsion explosives. The experiments were performed using a drop‐weight apparatus with transparent anvils. The effects of incorporating aluminium granules (∼100 μm in size) and glass microspheres (50 μm to 150 μm diameter) in the emulsion matrix were also studied. It was possible to record the flow of the emulsion both with and without additives. Of particular interest were observations of the onset and development of crystallization in the layer. In no case was there evidence for initiation of explosion.
Smoke generators. IV. The ignition of loose powder mixtures of pyrotechnic white smoke compositions containing hexachloroethane and silumin in sealed tubes
Authors: Hartley F. R. , Murray S. G. , Williams M. R. 
Published: December 2004

AbstractA small sealed tube has been used to study the reaction between hexachloroethane and silumin, which is important in certain types of smoke generating pyrotechnics. Standard amounts were heated at 483 K in a 12−cm3 tube. Products identified were aluminium chloride and tetrachloroethylene. The effects of added oxides were noted. Zinc oxide, magnesium oxide and cupric oxide inhibited the reaction. Ferric oxide accelerated the reaction and stannous oxide, zirconium dioxide and titanium dioxide seemed to have little effect. Other substances found to inhibit the reaction were ammonium chloride, water and ortho‐chloroaniline. Pentachloroethane was found as a product when water was present indicating the formation of pentachloroethyl radicals.
Smoke generators. V. Thermochemical investigation of pyrotechnic white smoke compositions containing hexachloroethane and silumin
Authors: Hartley F. R. , Murray S. G. , Williams M. R. 
Published: December 2004

AbstractSimultaneous differential thermal analysis with thermogravimetric analysis has shown that the inhibition of the ignition of silumin‐hexachloroethane smoke generators by zinc oxide is not due to the adsorption of hexachloroethane vapour on zinc oxide. Analysis of this and previously reported evidence suggests a free radical mechanism for the reaction of aluminium with hexachloroethane. Zinc oxide inhibits this by competition for radicals.
Thermal Decomposition of Energetic Materials XXIV. A comparison of the crystal structures, IR spectra, Thermolysis and impact sensitivities of nitroguanidine and trinitroethylnitroguanidine
Authors: Oyumi Y. , Rheingold A. L. , Brill T. B. 
Published: December 2004

AbstractThe crystal structure of trinitroethylnitroguanidine (TNENG) was determined by X‐ray diffraction for comparison with nitroguanidine (NGu). Pertinent crystal parameters are: orthorhombic, Pbca, a = 14.611 (7) Å, b = 11.973 (5) Å, c = 11.452 (5) Å, V = 2003 (2) Å3, Z = 8, D(calcd) = 1.758 g/cm3, R(F) = 6.30%, R(wF) = 6.58%. A hydrogen bonded network like that present in NGu is largely responsible for the lattice cohesion of TNENG. The IR spectrum of the condensed phase using slow thermolysis, and the gas phase using slow and fast thermolysis, suggests that parallel CN and NN bond fission reactions take place in both TNENG and NGu. The calculated and experimental values of the impact sensitivity of TNENG and NGu are compared. We conclude that the impact sensitivity and the thermal decomposition of TNENG are dominated by the characteristics of the C(NO2)3 group. The intermolecular hydrogen bonding that may desensitize nitroguanidine to impact has essentially no stabilizing effect on TNENG.
Emissionspectroscopy of Boron Ignition and Combustion in the range of 0.2 m̈m to 5.5 m̈m
Authors: Eisenreich N. , Liehmann W. 
Published: December 2004

AbstractBoron particle combustion is retarded by initial presence of an oxide coating. In current boron ignition models, oxygen is assumed to desolve in the oxide and diffuse to the B/B2O3 interface for reaction. One method to observe the reaction of boron with its surrounding atmosphere is the time resolved emission spectroscopy we applied in the range of 0.2 m̈m to 5.5 m̈m for different burning processes.In one experiment boron powder was burned in oxygen atmosphere initiated by an efficient pyrotechnic device. The energy transfer by the hot gases led to a glowing phase of the boron particles which then changed to a high temperature combustion and ended in a further glowing phase. The two glowing phases emitted continuous emission spectra, while the burning phase emitted the bands of BO and BO2.Another experimental setup was used to feed boron particles in a hot oxidizing atmosphere provided by a propane/air flame which flew into a combustion chamber. Herein the reaction of boron was recorded with high speed cinematography and time resolved emission spectroscopy. The flame contained a small amount of background radiation and we could identify emitted bands of BO, BO2, HBO2, CO and CO2.
Penetration Cutoff Velocities of Shaped Charge Jets
Authors: Held M. 
Published: December 2004

AbstractThe maximum depth of penetration, Pmax, of a shaped charge jet can theoretically be calculated from 5 quantities for the purely continuous, or for the initially continuous and then particulated, or for the fully particulated penetrating jet. These quantities are the distance Z0 of the target plate from the virtual origin, the value of γ (i.e. the square root of the ratio of target to jet density), the jet tip velocity vj,0 the efficient residual velocity vj,min, and the particulation time tp.Instead of calculating the individual values of vj,min for the individual depths of penetration Pexp at various standoff distances, this quantity can quite simply be read from the standoff diagram by means of the penetration cutoff lines‐ a so‐called Standoff/Cutoff‐diagram ‐, using the experimentally determined depth of penetration Pexp. The penetration cutoff lines are lines which start at the virtual origin and which represent the ideal increment in depth of penetration per jet velocity interval in the standoff diagram, the abscissas of this line corresponding to the jet tip velocities.The methods are demonstrated and explained, using the results of three firings with one type of shaped charge as an example. The shots were made at 6, 12, and 24 calibers standoff distance, and the cratering history was also determined in these trials.
Shaped Charge Jet Heating
Authors: Racah E. 
Published: December 2004

AbstractA one‐dimensional theoretical model of shaped charge jet heating is developed. The model includes heating due to the shock wave transferred to the liner by the explosive detonation wave and due to the plastic work performed during liner collapse and jet elongation. Results calculated by a one‐dimensional shaped charge computer code using this model fall within the lower bound of the experimental range.
Computations of ESR coupling constants in organic radicals. III. Nitro Derivatives of the Benzyl Radical
Authors: Hameka H. F. 
Published: December 2004

AbstractWe compute the ESR coupling constants and the geometries of ten nitro derivatives of the benzyl radical. We consider the three mononitrobenzyls, the six dinitrobenzyls and 2,4,6‐trinitrobenzyl. The computations are based on the use of the Gaussian 82 Program Package with the STO‐3G basis set. There are no experimental data available.
The Mott Fragmentation Model and the Vpl break‐up parameter
Authors: Hirsch Eitan 
Published: December 2004

AbstractIt is shown that the Mott fragmentation model and the Hirsch formula for the shaped charge jet break‐up time complete one another to yield a unified model. This model is consistant with the microscopic picture of internal flow splitting in the metal, into shear bands undergoing a strain larger than the average and the metal between them which undergoes a strain which is smaller than the average. This splitting reduces the deformation energy dissipated by the metal while elongating. It corresponds to the splitting of the stress versus strain characteristics of the metal into the isothermic and adiabatic curves as measured by Johnson and Cook. The parameter Vplwhich describes the break‐up process according to the Hirsch model, is identified with the expression (dσm/ϱ)1/2 where dσm is the difference in yield strength between the isothermic and adiabatic curves where the adiabatic characteristic becomes a maximum. The comparison with available experimental measurements of this prediction shows a very encouraging agreement. The weak dependence of Vpl on the strain rate on the one hand and the observed increase of the jet break‐up time in slowly elongating jets on the other hand are also explained using energy considerations. The recent recovery of jet particles by Zernow yields supportive evidence of the proposed theory which may be extended to all semi steady metal plastic flow phenomena. The final break‐up, according to this model is due to the separation between the two sides of shear bands where the slide motion went on during the whole deformation process.
Gun Muzzle Blast and Flash
Authors: Klingenberg G. 
Published: December 2004

AbstractGun muzzle blast and flash phenomena are of importance since they are associated with the formation of large overpressures and intense muzzle flash. About 30% of the chemical energy released from the propellant used in a conventional gun is converted into kinetic energy of the projectile. The remaining energy is mainly contained in the propellant gas‐particle mixture which escapes from the muzzle of the gun in a few milliseconds. The sudden discharge produces a blast wave because of the rapid displacement of air originally surrounding the gun. In addition, these gases are generally fuel‐rich and mix with air turbulently entrained from the surroundings. Combustion of this mixture causes gun muzzle flash, usually associated with the formation of a secondary blast wave. The design of solid propellant charges, gun performance, muzzle attachments and chemical flash suppressants is guided by the need to keep the above hazards to safe limits. In this paper, blast and flash phenomena are characterized using data of recent investigations and showing illustrative examples of their development.
A New Method Rapidly Measuring Nitroglycerin in the coating of the rocket propellant
Authors: Kong Yang‐Hui , Liu Zi‐Ru , Yin Cui‐Mei , Wu Cheng‐Yun 
Published: December 2004

AbstractIn this paper an application of thermogravimetric‐derivative thermogravimetric analysis (TG‐DTG) to the measurement of the nitroglycerin (NG) in thc coating of the rocket propellant was developed. In comparisons with gas chromatography (GC) and weight method (WM), TG‐DTC has been confirmed to he even more available to measure rapidly migration of NG in thc coating. The new method is accurate to within ± 0.5% and its standard deviation is O.1. The method is of actual significance in respect of thc investigation of the migration regularity of plasticizer, the selection for coating materials and the prediction of service life of the solid propellants.
Internal Shearing during Shaped Charge Jet Formation and Break‐up
Authors: Hirsch Eitan 
Published: December 2004

AbstractDuring jet formation and elongation, the shaped charge linear material is subject to forces which vary extremely in both magnitude and direction. As a result, the direction in which the slip planes are formed in the material, changes so as to comply with the force direction and strength. By following the direction of the slip planes from the beginning of liner motion until the jet breaks up, it is possible to suggest a description of the internal changes occurring in the material during liner collapse, jet formation, and jet elongation. The mechanism obtained by this study may account for the slight systematical deviation by a jet from the original shaped charge axis of symmetry, such as has been measured very accurately using the orthogonal synchro‐streak technique (OSST) developed by Held. The mechanism may also explain some jet details observed in OSST photographs and flash radiographs. The modeled mechanism identifies the possibility that some basic differences may exist between the break‐up process occurring in expanding rings and shells and the break‐up process occurring in shaped charge jets.
A study of Explosive Compositions Containing Ammonium Perchlorate
Authors: Gimenez P. , Lecume S. , Groux J. 
Published: December 2004

AbstractFive compositions incorporating octogen with an energetic binder, a reference composition and four compositions containing ammonium perchlorate, were studied experimentally by measuring the detonation velocity versus the diameter, by performing the cylinder test and a frontal projection test using a VISAR interferometer. The results obtained are treated in the frame means of the ZND phenomenological model extended to nonideal explosives and by using an adaptation of Kamlet's method. The conclusions drawn from this study are:

– the phenomenological model is in line with the experimental results,
– AP is entirely decomposed in the steady‐state zone,
– the recombination reactions between the oxygen, released by the AP, and the carbon, released by other components, occur completely in the steady‐state zone in the case of small grain‐size AP (10μm),
– these reactions are prolonged, for a few microseconds, in the non steady‐state zone in the case of large grain‐size AP (200μm),
– In this case, the heterogeneity of the material is reflected in the structure of the detonation wave which shows a Von Neumann shock with a finite rise time (30 ns).
The methodology developped in this work can be used for the study of the majority of non ideal explosives.
Structure and Tautomerism of ANTA (aminonitrotriazole)
Authors: De Paz Jose‐Luis G. , Ciller Juan 
Published: December 2004

AbstractEnergy and dipole moment calculations show 3‐nitro‐5‐ amino‐1,2,4‐triazole is the most stable tautomer of ANTA either in the gas phase and polar solvents, in agreement with X‐ray findings. Our calculations predict that the 5‐nitro‐3‐amino‐1,2,4‐triazole tautomer is more sensitive to shock or impact. Some discrepancies between semiempirical (AMI and PM3) calculations and ab initio (up to 6‐31G*//6‐31G) are studied.
Explosive properties of the compositions CCl4 + Al + ZnO
Authors: Syczewski M. 
Published: December 2004

AbstractThe compounds CCI4 + Al + ZnO were suitably prepared, so that its ability to detonate could be investigated. The detonation velocity (D) dependence on the charge density (ρ) has been established. The increase of density above 1.8 kg/dm3 particle velocity was measured. Extraordinarily low parameters of detonation are explained by the special peculiarity of the explosion products.
Testing the Precision Initiation Couplers
Authors: Held Manfred 
Published: December 2004

AbstractIt is possible to properly test a Precision Initiation Coupler (PIC) for its detonation profile and the rotational symmetry of its detonation wave using the Multi‐Streak and/or Flash‐Gap‐Technique both with central linear streak line and circle streak which is comprised of dots for better evaluation.