bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pot Life Problem and its measure with a reduced smoke propellant production
Authors: Tokui Harusuke , Iwama Akira 
Published: May 2005

AbstractTypical reduced smoke type composite propellants mainly composed of hydroxyl‐terminated polybutadiene (HTPB) and ammonium perchlorate (AP) have a drawback that these propellant grains have a high response function of the burning rate to cause acoustic pressure oscillation. The addition of a small fraction (0.5% ∼ 1.2wt%) of zirconium (Zr) or zirconium oxide powders to propellant compositions has been known to be effective for suppressing such a combustion instability. It is also notified, however, Zr powder would incur the acceleration of urethance forming reaction so as to make the pot life of the HTPB/AP propellant dough shorter. This paper reports that tetracycline (TC) is available to offset such a trouble in curing process brought about by Zr powder addition.
Diagnostics of the reaction behaviour of Less Sensitive High Explosives under jet attack
Authors: Held Manfred 
Published: May 2005

AbstractDefinitive conclusions about high and low order reactions can be drawn from individual framing‐mode pictures of a rotating mirror camera record, when both the vellocity of the axial propagation of the reaction along the outer contour and the velocity of radial expansion of the reaction products are analysed at various distances from the plane of initiation. In this, the intensity of the reaction can be assessed quantitatively from the radial expansion velocites, even when, for example, a penetrating shaped charge jet induces an axial drag wave in the test charge. A detailed description is given of the test set‐up and of the test results obtained with charges exposed to the impact of a shaped charge jet.
Energetics of Nitro/Azide Propellants
Authors: Nakashita Goro , Kubota Naminosuke 
Published: May 2005

AbstractA new type of double‐base propellant which contains GAP was studied in order to elucidate the burning rate characteristics and combustion wave structure. This class of propellants is termed “nitro/azide propellants”. Experimental results revealed that the burning rate and temperature sensitivity are increased when 12.5% DEP is replaced with 12.5% GAP. The reaction rate in the dark zone is increased by the replacement of DEPo with GAP. However, the gas phase structure of NG/NC/GAP propellant is fundamentally the same as that of NG/NC/DEP propellant and the basic chemical reaction mechanism in the gas phase zone remains unchanged for both propellants.
1,4‐Dinitrocubane and Cubane under High Pressure
Authors: Piermarini G. J. , Block S. , Damavarapu R. , Iyer S. 
Published: May 2005

AbstractThe effects of pressure on the chemical reactivity, phase behaviour and thermal decomposition of energetic materials can be studied by a combination of measurement techniques in conjunction with a high pressure diamond anvil cell and the ruby fluorescence method of pressure measurement. These techniques include: (1) optical polarizing microscopy and (2) Fourier transform infrared (FTIR) spectroscopy. Recent results on the study of 1,4‐dinitrocubane and cubane will be presented.
Study of Detonation of Aluminium Sensitized Slurry Explosives containing organic fuels
Authors: Maranda A. 
Published: May 2005

AbstractResults are presented of measurements of the critical diameter and the detonation velocity of aluminium sensitized slurry explosives containing various organic fuels. The particular organic components differ with regard to solubility in water and oxygen balance. A physicochemical interpretation of the obtained results is advanced, based on the results of measurements of the detonation parameters and the analysis of the liquid phase of the tested explosive mixtures.
Stabilizer reactions in cast double base rocket propellants. Part II: Formation and subsequent reactions of N‐nitroso derivatives of para‐nitro‐N‐methylaniline and 2‐nitrodiphenylamine in mixed‐stabilizer propellants aged at 80°C and 90°C
Authors: Bellerby J. M. , Sammour M. H. 
Published: May 2005

AbstractThe HPLC determination of the stabilizers para‐Nitro‐N‐methylaniline (pNMA) and 2‐Nitrodiphenylamine (2NDPA) and their derivatives in two mixed‐stabilizer cast double base rocket propellants undergoing accelerated aging at 80°C and 90°C has led to the conclusion that N‐nitroso derivatives play a critical role in the stabilizer depletion processes in this type of propellant. In order to account for the principal stabilizer products in the aged propellants it is suggested that pNMA enters into an equilibrium with its N‐nitroso derivative (formed during the initial stages of aging) and that this reacts with 2NDPA in a transnitrosation reaction, to give mainly N‐nitroso‐2NDPA from which the observed C‐nitro derivatives of 2NDPA are in part generated by rearrangement and subsequent oxidation.
The Mechanism of Filler Reinforcement from addition of neutral polymeric bonding agents to energetic polar propellants
Authors: Kim C. Sue , Noble Paul N. , Youn Chung H. , Tarrant Darcy , Gao Andrew 
Published: May 2005

AbstractIt has been demonstrated that addition of small amounts of the newly developed neutral polymeric bonding agents (NPBA's) to energetic propellants such as HMX/PEG/NG composites causes strong filler reinforcement. The mechanism of this reinforcement occurs through interfacial effects, and not because of an overall increase in the crosslink density of the binder. It has been demonstrated directly that the NPBA's have a favorable relative affinity for HMX and concentrate at the solid surface during mixing. All the experimental evidence supports the theory that highly crosslinked polymeric shells form around the HMX particles and chemically bond to the binder matrix during the cure, thus causing an increase in the initial modulus. Furthermore, these shells appear to eliminate the weak, soft layers around the particles, and hence filler reinforcement persists up to much higher elongation than without addition of NPBA. Based on the filler reinforcement observed, the simple one‐step procedure of incorporating our NPBA is almost as effective as the more costly process of precoating the particles.
Fuel Regression Mechanism in a Solid Fuel Ramjet
Authors: Hadar Ilan , Gany Alon 
Published: May 2005

AbstractA model relating the combustion characteristics, particularly the regression rate, to the fuel properties in a solid fuel ramjet (SFRJ), is presented. The analysis is based on inspecting the different phenomena (e.g., chemical kinetics and heat transfer) involved in the fuel decomposition process in order to determine the rate controlling steps, and modeling the important mechanisms. Model predictions were compared to experimental findings for four polymeric fuels, showing excellent qualitative agreement in classifying different fuels, as well as good quantitative predictions of the fuel regression rates. The model can serve as a useful tool for the selection of appropriate fuels, as well as for preliminary design of the engine and mission profile prior to static firings of the final SFRJ prototype.
Impact Testing Methods for Gun Propellants
Authors: Varga Ludovit 
Published: May 2005

AbstractA tower‐type drop‐weight tester is used to characterize mechanical properties of LOVA gun propellants ata nominal strain rate of 300 s−1. This study is a comparative evaluation of two testing methods, namely the original and the newly introduced one, that differ in the initial experimental setup. The results of the evaluation show that with the original testing method, the specimens are strained nonlineraly which, at times, has led to an anomalous compressibility reduction of the specimen. The newly introduced testing method improves the strain rate control and uniformity in addition of having a very good results‐reproduction capability.
Thermal expansion, transitions, sensitivities and burning rates of HMX
Authors: Herrmann Michael , Engel Walter , Eisenreich Norbert 
Published: May 2005

AbstractThe phases of HMX and their transitions were investigated by thermal analysis using X‐ray diffraction. Series of diffraction pattern were measured, while the samples were heated and cooled. The thermal expansion coefficients and the colume changes at the transitions were extracted from the diffraction series. A contraction of β‐HMX was found before changing into δ‐HMX resulting in a high volume difference during the transition. On cooling, the reconversion of the high temperature phase requires days. It is further slowed down by decomposition products, which are formed at temperatures beyond 490 K. The final reconversion results in mixtures of α‐and βHMX.The mechanical sensitivities and the buring rates of the HMX phase were determined. The high sensitivity of δ‐HMX against impact together with its slow reconversion creates handling risks when the HMX is exposed to temperatures above 440 K.
Use of Dynamic Mechanical Measurements to determine the aging behavior of solid propellant
Authors: Husband D. Mark 
Published: May 2005

AbstractA process for determining the aging characteristics of solid rocket propellants by measuring their dynamic mechanical properties is described. Samples of rocket propellant are tested using a mechanical spectrometer at low strain levels and low frequencies. The change in the dynamic storage modulus of the propellant with aging time and temperature is used to determine the aging rate anf the likely mechanisms occuring during aging. The technique is advantageous is several respects:
because the tests are non‐destructive and use small test specimens, and entire aging program can be conducted using much less propellant than is required ihn traditional aging programs (propellant requirements are reduced by more than an order of magnitude)
the technique can be applied to samples with unusual or unique geometries which cannot be tested using traditional methods;
test specimens can be obtained directly from live, operational solid rocket motors, and service life and mechanical property degradation can be determined.
Determination of the Temperature in a Solid Propellant Flame by analysis of emission spectra
Authors: Eckl Wilhelm , Eisenreich Norbert 
Published: May 2005

AbstractTwo methods are described to determine the temperature in a solid propellant flame by analysis of emission spectra. First, experimental spectra of NH and CN radicals were compared with calculated spectra using a least squares fit routine with the parameters temperature T and halfwidth of the line profile Δλ. Second, in flames where no or only small band intensities were observed, the occurring continuous spectra were fitted to a Planck radiation. The emission coefficient ϵ was there by suggested as a function of wavelength λ and temperature T. The first technique was applied to the nitrmine propellant HMX, the second to a composite propellant consisting of 15% AI, 15% GAP and 70% ammonium perchlorate. TO detect the emission, propellant strands were burnt in an optical bomb under nitrogen atmosphere at various pressures (octogen at 0.1 MPa, composite at 2 MPa). To calibrate the intensities of the continous spectra tungsten strip lamp was used. The maximum time resolution of the used spectrometer system is about 10 ms. The determined temperature range was from 2300 K to 3000 K, which is about 20% below the corresponding adiabatic temperature (nitramine propellant: 2900 K, composite propellant: 3500 K).
Syntheses of 3,3′ ‐Disubstituted Polynitrostilbenes
Authors: Zeng‐guo Feng , Boren Chen 
Published: May 2005

AbstractThis paper describes the syntheses of 3,3′‐disubstituted tetranitrostilbenes with increasing the electron‐donting ability of substituting groups (MeNH > MeO > Cl) on the benzene rings. Two of them are nitrated to form 3,3′ ‐disubstituted methylnitroamino hexanitrostilbenes. Also observed is that the methylnitroamino group is not converted into the amino group and only the methoxy group can be substituted by the amino group in 3‐methoxy‐3′‐methylnitroamino‐2,2′, 4,4′, 6,6′‐hexanitrostibene is obtained.
Optimizing the mixture blending for castable aluminized plastic‐bonded explosives
Authors: Jeng Yann‐Chyn , Perng Huey‐Cherng , Yeh Hsi‐Cheng , Chang Ming‐Ju 
Published: May 2005

AbstractCastable aluminized plastic‐bonded explosive (PBX) is a multiple components blending. To find an optimum mixture blending (formulation) for PBX to meet several required specifications is formidable. This is due to the fact that there are unlimited candidate formulations from which an appropriate one could be chosen. In general, trial and error type of engineering judgement is still the primary approach to reach the desired goal.This paper, however, employs a statistical approach named Mixture Experiments as well as an optimization routine called Eureka to find the optimum formulation, which meets five required specifications. Finally, two confirmation runs are performed. The results justify that the theroretical solution derived from the systematic statistical approach is indeed applicable.
Energetic Solid Fuels for Ducted Rockets (III)
Authors: Kubota N. , Miyata K. , Kuwahara T. , Mitsuno M. , Nakagawa I. 
Published: May 2005

AbstractDucted rockets operate with the combustion of fuel‐rich gas generated in a primary combustor and the ram‐air induced from the atmosphere to a secondary combustor. Thus, the combustion performance depends on the mixing and reaction processes of the fuel‐rich gas and the air flow in the secondary combustor. The energetic solid fuels examined in this study consisted of ammonium perchlorate based composite propellants containing boron particles. The combustion efficiency of boron particles in the secondary combustor was determined as a function of air‐mixing process and air/fuel ratio. Two types of air‐inlet were used to evaluate the combustion of boron particles. Combustion tests conducted by direct connect flow indicate that the combustion efficiency increased significantly when a multi‐port consisting of two forward‐ports and two rear‐ports was used.
Les essais de sécurité pyrotechnique: Présentation de moyens et d'exemples d'application
Authors: Fabre A. , Ruault O. , Leveque M. , Grange A. , Bidault C. 
Published: May 2005

AbstractLa Délégation Générale pour l'Armement dispose au travers de ses centres techniques notamment l'Etablissement Technique de Bourges (E.T.B.S.) d'une longue expérience dans le domaine de la pyrotechnie et plus particulièrement de la pyrotechnie militaire.Le Laboratoire Poudres et Explosifs (L.P.E.) est le laboratoire de référence de l'état fran¸cais pour la pyrotechnie militane. II réalise des recherches et des études chimiques, physiques et mécaniques sur tous les produits pyrotechniques (explosifs secondaires, explosifs primaires, propergols, poudres propulsives, compositions pyrotechniques.).La législation fran¸caise, notamment le décret 79‐846 du 28 Septembre 1979, appliquée à tous les établissements impliqués dans une activité pyrotechnique, impose la réalisation d'études de sécurité d'environnement du travail. La réalisation de ces études et des essais spéciaux a pour but la réduction de la fréquence, de la probabilité et de la gravité des accidents ou incidents susceptibles de survenir sur un poste de travail. En conséquence de quoi une partie des travaux du laboratoire porte sur cette activité.Dans les pages suivantes, il sera présenté les caractéristiques de l'installation permettant la réalisation d'essais de sécurité en grandeur réelle ainsi que quatre exemples d'applications.
Functional and chemical characterization of the aging process of an igniter
Authors: Spasojevic̈ Ivan , Batinic̈‐Haberle Ines , Baris̈in Dubravka 
Published: May 2005

AbstractThe igniter consisting of 34% Mg, 60% KNO3, 3% KClO4 and 3% organic binder was subjected to accelerated aging under the conditions of 85% relative humidity at 65°C, 75°C and 85°C, and at 75°C with 92% relative humidity. Chemical aging was followed through formation of Mg(OH)2 and KNO2. Functional characterization was accomplished in a device constructed to enable simultaneous determination of the heat of combustion and pressure‐time recording of the combustion process of both fresh and aged samples.The maximum acceptable deterioration occured at different times depending upon the conditions. The acceleration factor for every 10°C at 85% relative humidity is on average 2.8, leading to a prediction of shelf life of not more than 4 years at 25°C. At the time when burning characteristics were significantly changed, the mixture suffered only slight chemical changes, with only about 1% Mg(OH)2 and 0.5% KNO2 being formed. Thus, no chemical changes should be tolerated in such formulations.
Electrochemical Study on TAGN. A differential pulse polarography determination
Authors: Pëarez De Diego Martïanez A. 
Published: May 2005

AbstractThis work shows an electrochemical study about triaminoguanidine nitrate, estimating the influence of the reaction compounds for the formation of TAGN and secundary compounds and hydrolysis products of this formation reaction. The conditions to determine polarographically the content of TAGN in a propellant without the interference of those compounds are verified. The method used is the differential pulse polarography in aqueous medium, due to the high solubility of TAGN in water. We have used three different media as electrolyte support, verifying the influence of different variables, as pH, drop time etc., to obtain the optimum work conditions.
On the Kinetics of Chemical Reactions in Solids Under Shock Compression (a review)
Authors: Batsanov S. S. 
Published: May 2005

AbstractConsideration is given to physical and chemical methods useful for a proceeding time of chemical reactions under compression due to impact and, also, to diffusion‐process peculiarities. Experimental data enable us to conclude that solid‐phase reactions may be accomplished for times of the order 1‐10 μs. The mechanism governing enhanced diffusion rate at the moment of impact has been proposed and experimentally confirmed.
Non‐Reactive HMX Shock Hugoniot Data
Authors: Simpson Randall L. , Helm Frank H. , Kury John W. 
Published: May 2005

AbstractModified wedge tests and in situ pressure gauges have been used to measure the shock Hugoniot of HMX/water(1) mixtures. Making the assumption that the mixture is macroscopically homogeneous and isotropic, these data, and literature values for the equation of state of water, are used to deduce the Hugoniot of pure HMX. Shock strengths below 6.0 GPa produced no significant reaction near the shock front. Radiometric observation of the shocked mixture supports this conclusion. The new HMX shock velocity versus particle velocity curve is significantly below that published for solvent pressed HMX. Reactive flow hydrodynamic calculations indicate that as much as 3% – 7% HMX may have reacted in the experiments with solvent pressed material.
Liquid rubber epoxy blends for Inhibition of Composite Propellants
Authors: Agrawal J. P. , Gupta D. C. , Chouk M. P. , Khare Yogesh 
Published: May 2005

AbstractLiquid rubbers, i.e. polysulphide (PS) and polybutadiene‐acrylic acid‐acrylonitrile (PBAN) have been blended with Dobeckot E‐4 (commercial novolak epoxy resin) in different proportions. These systems have been cured using polyamine/polyamide curing agents and were characterized using gel time, % elongation, tensile strength and bond strength with composite propellants, heat resistance, dioctyl adipate(DOA) absorption, oxygen index, thermal conductivity and brittleness temperature. The data generated for various characteristics indicate that the formulations E‐PS‐9 and E‐PBAN‐2 are promising inhibition systems for composite propellants.The inhibition of composite propellants has been done with rayon thread impregnated with the formulations E‐PS‐9 and E‐PBAN‐2 using filament winding technique. The successful static evaluation of inhibited composite propellants at ambient, elevated and sub‐zero temperatures proves the suitability of these systems for inhibition.
An Analytical Model for the Particulation of a Jet from a shaped charge liner
Authors: Walters William P. , Summers Richard L. 
Published: May 2005

AbstractA new model is presented to predict the cumulative breakup time of the jet from a shaped charge liner. The model invokes a plastic instability criterion, kinematic considerations, and a material constitutive equation. Very good agreement of the cumulative breakup time and jet length with experimental data for several copper liner geometries is shown. The results are dependent on the initial strain rate and jet temperature distribution.
Investigations on Polyvinyl Nitrate as a High Energetic Material
Authors: Durgapal U. C. , Dutta P. K. , Mishra S. C. , Pant Jyotsna 
Published: May 2005

AbstractPolyvinyl nitrate (PVN) is one of the few known polymeric explosives. PVN was prepared by controlled addition of cooled nitric acid to a pre‐cooled suspension of polyvinyl alcohol in acetic anhydride and subsequent processing of the reaction product. Nitrogen content of different PVN samples was in the range 11.76% to 15.71%;, and the molecular weight about 100000. Several properties of PVN have been investigated and correlated with its degree of nitration. Scanning electron micrographs of PVN fibres show a porous surface. Abel heat test values at 82°C indicate that fibrous PVN has a fairly good degree of stability, which decreases with increase in its % N. Addition of small amounts (0.25%; by wt.) of DPA, 2NDPA, carbamite and resorcinol into PVN (15.71%; N)improves its heat stability. With increasing %;N, ignition temperature of PVN decreases and impact as tetryl. With increasing %; N from 11.76%; to 15.71%;, heat of combustion decreases from 3744 cal/g to 3023 cal/g, and heat of explosion increases from 456 cal/g to 987 cal/g, due to increase in oxygen balance.
Study on the Nitrolysis of Hexamethylenetetramine by NMR spectrometry
Authors: Fang Zhijie , Chen Li , Wang Shaofang , Chen Ju , Li Fuping 
Published: May 2005

AbstractThe nitrolysis of hexamethylenetetramine (hexamine, HA) and 1,3,5‐trioxane was studied by NMR spectrometry. It was found that the structure of the nitrolysis products of the trioxane could be monomethylenedinitrate, dioxymethylenenitronitrate and trioxymethylenenitronitrate, O2N(OCH2)nONO2(n = 1,2,3). Comparison of the 1H and 13C spectra of the nitrolysis mixture of HA with the nitrolysis products of trioxane proved that in the nitrolysis mixture of HA the methylene group which cannot be used to form 1,3,5‐triazacyclohexane (hexogen, RDX)appears in compound (2) and not in compound (1).
Influence of the Initiation Intensity on the Radial Detonation Breakthrough
Authors: Held Manfred 
Published: May 2005

AbstractInitiation intensity of a booster charge was varied by inserting plexiglass layers of different thicknesses. The time differences between shockwave arrival in the acceptor charge and the axial and radial detonation breakthroughs were determined, as well as the distance of the first radial breakthrough from the initiation plane ‐ referred to as the 90° distance Δs or Corner Turning Distance (CTD). Changes in the initiation time and Δs are small as long as the initiation intensity is sufficiently above to the threshold value. This result applies for cast explosive charges, TNT/RDX (35/65), Composition B type charges, and high performance pressed charges, HMX/Binder (96/4).