bluuebunny/crossref_metadata_2025 huggingface dataset:
Pot Life Problem and its measure with a reduced smoke propellant production
Authors: Tokui Harusuke , Iwama Akira
Published: May 2005

Typical 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

Definitive 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

A 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

The 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.
The Role of Liquid Propellants in insensitive munitions policy
Authors: Bonner B. H.
Published: May 2005

The role of liquid propellants in insensitive munitions policy has been reviewed. Liquid propulsion systems meet the policy requirements by giving a reaction no more severe than burning and mitigation techniques can be applied to limit even this response.
Study of Detonation of Aluminium Sensitized Slurry Explosives containing organic fuels
Authors: Maranda A.
Published: May 2005

Results 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

The 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

It 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

A 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

A 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

The 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

A 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

Two 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

This 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.
Steady Detonation Velocity D∞ of Infinite Radius derived from small samples
Authors: Held Manfred
Published: May 2005

A method will be proposed for determining the detonation velocity for a very large charge, using only a small specimen. In detail will be described the background theory, the layout of test charges, the test set‐up used, and the results 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

Castable 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

Ducted 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

La 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

The 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

This 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

Consideration 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

Modified 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

Liquid 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.
A Review of Jet Breakup Time Models
Authors: Walters William P. , Summers Richard L.
Published: May 2005

A review of the literature on the particulation of a jet from a shaped charge liner is presented. Particular emphasis is placed on existing, open literature, analytical models designed to predict the jet breakup time. Also, the various experimental techniques used to obtain the distribution of jet breakup times are elucidated.
An Analytical Model for the Particulation of a Jet from a shaped charge liner
Authors: Walters William P. , Summers Richard L.
Published: May 2005

A 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

Polyvinyl 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

The 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

Initiation 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).
Hydrogenated Hydroxy‐Terminated Polyisoprene as a Fuel Binder for composite solid propellants
Authors: Iwama Akira , Hasue Kazuo , Takahashi Terue , Matsui Kiyoshi , Ishiura Kazunari
Published: May 2005

The synthesis and application of hydrogenated hydroxy‐terminated polyisoprene (HHTPI) to a fuel binder of composite solid propellants were attempted. An HHTPI prepolymer was synthesized through the hydrogenation for the hydroxy‐terminated polyisoprene (HTPI) in the presence of nickel and zirconium catalysts over kieselguhr in 2.0 MPa hydrogen and at 443 K – 453 K for 24h. A prepolymer of a number‐averaged molecular weight 2500–3800, provided a viscosity level required for the use of a fuel binder from which solid propellant can be possibly made by means of direct casting method. Thermal stability and aging characteristics of HHTPI elastomer against environmental attacks are superior to those of HTPB. Some plasticizers and bonding agents can bring about the acceptable mechanical properties to the propellant grains mainly composed of HHTPI, ammonium perchlorate and aluminium powder. The linear burning rates of HHTPI‐based propellants are at the same level with that of HTPB‐based propellants. However, the composition that gives the maximum performance with HHTPI‐based propellants, shifts to 1–2 wt% fuel‐rich side from the most adequate fuel content 12 wt% in HTPB/AP/Al. The HHPTI propellants indicated the similar burning rate as HTPB‐based propellants in the linear burning rates in spite of the comparatively poor ignitability. Nevertheless, the static tests of 100 mm dia. sounding rocket motors are successfully performed by an ignition operation at the pressurized condition. The ballistic performances are not inferior to those of the HTPB‐based propellants.
Low and High Order Detonation in Tetryl
Authors: Leiper G. A. , Cooper J.
Published: May 2005

The detonation behaviour of tetryl has been investigated by analysing published charge diameter effect data for two mesh sizes of powders, using slightly divergent flow theory. Evidence found within the published data for the existence of high and low order detonation velocities regimes has been substantiated. The form of the global heat release function during low order detonation was found to be of the hot spot/grain burning type, and during high order detonation, of the thermal explosion type. Particle size effects are discussed both for low and high order detonation. The observed stability of low order detonation at the smaller charge diameters is explained in the model used, which predicts a ‘forbidden zone’ in shock velocity/inverse charge diameter space. The kinetics are discussed in terms of the pressure dependent functional form used in the CPeX detonation model, and models of hot spot formation in powder explosives.
Solid Propellant Degradation Kinetics via headspace sampling gas chromatography
Authors: Judge Michael D.
Published: May 2005

The degradation kinetics of solid rocket propellant based on a glycidyl azide polymeric binder with ammonium nitrate were determined by gas chromatographic quantitation of the headspace gases over heated samples. This approach was found to allow the determination of degradation at temperatures approaching ambient. An Arrhenius plot was constructed from the data and kinetic parameters, including activation energy and relative rates of degradation, were calculated. Two different batches of propellant were found to exhibit similar degradation kinetics, although one was estimated to have a shorter service life based on the relative volumes of gases liberated.
Influence of product species selection on thermochemical equilibrium calculations. Part I: Energetic materials
Authors: Greenlee C. L. , Butler P. B.
Published: May 2005

Chemical equilibrium calculations are made for a number of Carbon C, Hydrogen H, Nitrogen N, and Oxygen O, explosive compositions. A methodology is established to systematically limit the number of product species available in thermochemical equilibrium calculations. The calculations are then compared with “baseline” results obtained using an extensive product species library consisting of 900 gas‐phase and 600 condensed‐phase product species. Errors in bulk thermodynamic properties (detonation velocity and pressure) and in product chemical composition are quantified in terms of the number of species considered as products of reaction. The properties at states along an expansion isentrope are also presented.
High energetic materials: Reaction of Azides with Dioxygenyl Salts
Authors: Holfter Hagen , Klapötke Thomas M. , Schulz Axel
Published: May 2005

The reactivity of sodium azide, activated sodium azide and hydrazinium azide towards various dioxygenyl salts was studied. Under no circumstances the formation of dioxygenyl azide, O2N3, could be observed. This is in agreement with high level quantumchemical ab initio computations at correlated level (MP2, PMP2, CISD), predicting the decomposition of hypothetical O2+(g)/N3−(g) to be thermodynamically highly favorable (MP2: −326; PMP2: −328; CISD; −369 [kcal/mol]). The combustion of O2BF4 with either N2H5N3 (spontaneous reaction on contact in a coaxial solid‐propellant system) or NaN3 (safe to handle, highly exothermic reaction after ignition) is discussed in terms of high‐energy‐density materials (HEDM).
The Use and Application of Red‐Phosphorous Pyrotechnic Composition for camouflage in the infrared region of radiation
Authors: Klusáček Ladislav , Navrátil P.
Published: May 2005

Under laboratory conditions, there were detected burning products of pyrotechnic compositions based on red phosphorus with epoxy resin being especially trihydrogenphosphoric acid, tetrahydrogendiphosphoric acid and mixture of cyclo‐triphosphoric acid, cyclo‐tetraphosphoric acid and cyclo‐hexaphosphoric acid. In burning products of pyrotechnic composition with magnesium added there was detected only cyclo‐triphosphoric acid among cyclic derivatives. Phosphorous aerodispersions generated from smoke grenades containing these pyrotechnic compositions under field conditions could screen infrared radiation (0.82 μm, 3–5 μm, 10.6 μm wavelengths) with high efficiency. Examined pyrotechnic compositions of plasticized red phosphorus with epoxy resin proved to be suitable for smoke grenades of modern construction with both fast and slower generation of phosphorous aerodispersion.
Diagnostics of the Profile and Rotational Symmetry of a Detonation Wave
Authors: Held Manfred
Published: May 2005

It is possible to record a detonation wave profile and to conduct a detailed analysis on its various symmetrical levels and on the rotational symmetry of a detonation wave in only “one” test by using a specific streak mask and applying multi streak or flash gap technique.
Modification of Thermal Theories to Solid Propellant Ignitibility
Authors: Su Fu‐Hu
Published: May 2005

The conventional thermal theories are inventively modified for analyzing the ignition behaviors of solid propellants. Based on the modification of the thermal theory with the boundary condition of constant heat flux, the effects of heat flux, pressure, threshold of heat flux and absorbability on the radiant ignition of solid propellant are elaborated. The innovations of theoretical analyses are consistent with most of experimental results depicted in literatures. That the increase of hot gas velocity increases the ignition time of solid propellant is verified to be attributable to the decrease of hot gas temperature, ascertaining insight of the thermal theory with the boundary condition of flowing hot gas. In addition, a tentative estimation of pressurization rate effect on ignition time of solid propellant is proposed.
Influence of energetic materials on the energy‐output of gun propellants
Authors: Volk Fred , Bathelt Helmut
Published: May 2005

For the formulation and preparation of gun propellants containing high energetic compounds, methods have been described how to improve the performance. In addition thermodynamic data such as flame temperature, mole number, mean molecular weight, heat of explosion and specific energy were discussed, which are of main influence for the energy‐output of energetic materials. In connection with the improvement of performance, a list of components was established, which could be used to increase the energy without increasing the sensitivity of the propellants. At first, the aim was to replace conventional plasticizers by several energetic plasticizers. Taking into account different propellant formulations, the thermodynamic parameters have been calculated which are of interest for improvement of the specific energy. On the other hand, nitramine propellants manufactured at our Institute using different binder systems such as polybutadiene (PB), glycidylazide polymer (GAP) and cellulose acetate butyrate (CAB) have been investigated in a closed bomb in order to evaluate the energy‐output and in addition the reaction products by gas analysis. The performance of these LOVA‐propellants was discussed in connection with heat of formation, oxygen balance and the kind of polymeric binder system. Finally, energetic compounds such as NTO, CL‐20, TNAZ, ANTA and ammonium dinitramide (ADN) have been calculated using the ICT‐Thermodynamic Code, in order to assess the energy‐output and to be able to discuss a possible improvement of the performance.
Kinetic modelling of the stabilizer consumption and of the consecutive products of the stabilizer in a gun propellant
Authors: Bohn Manfred A. , Eisenreich Norbert
Published: May 2005

Diphenylamine is used for the stabilization of solid propellants based on nitrocellulose. It reacts with the autocatalyticly acting decomposition product of nitrocellulose and forms consecutive products, which also stabilize. The kinetics of these stabilizing reactions are described by four reaction models. With respect to DPA and the DPA consecutive products the models have one, two and four steps. The four step model contains the DPA consecutive products up to trinitro‐DPA. By approximations an analytical equation for the stabilizer decrease could be derived, which describes the stabilizer consumption very well. The other equation systems have been integrated numerically by a Runge–Kutta procedure and their reaction rate constants have been obtained by a non‐linear least squares fit parameter calculation. This allows an evaluation of the reaction kinetic models. Relative reactivities of the DPA consecutive products with respect to DPA are calculable with the obtained reaction rate constants and an effective DPA concentration can be established. The different reactivities of mixed stabilizers as MNA and 2‐NO2‐DPA can be described with the presented method of modelling.
Controlled pyrolysis of the new energetic binder azide polyester PAP‐G
Authors: Pfeil Achim , Löbbecke Stefan
Published: May 2005

The degradation mechanism of the azide polyester PAP‐G (poly‐2,2‐bis(azidomethyl)‐1,3‐propandiol‐glutarate) on controlled pyrolysis differs from that of the polyether GAP (glycidyl azide polymer). The decomposition is more intensive, involves more of the carbon backbone and occurs at lower temperatures. As an energetic component in a propellant it tends to disintegrate at an early stage giving off cabonaceous material of the polymer structural backbone.

Mixed metal oxides in the doped binder samples affect neither the reaction enthalpy nor the reaction products. However, they accelerate the nitrene formation by shifting the reaction interval to lower temperatures. Shifts up to 20 K were observed. In the case of PAP‐G the effect is most expressed by the additive MOVO whereas for GAP, in opposite, copper chromite is most effective.
Radiation Emitted from Rocket Plumes
Authors: Deimling Lukas , Liehmann Wolfgang , Eisenreich Norbert , Weindel Martin , Eckl Wilhelm
Published: May 2005

The signature of rocket plumes can be used for detection, identification and guidance of rockets. The objective was to investigate the signature of various types of solid rocket propellants by application of spectroscopic methods. The emission and transmission characteristics of plumes were studied experimentally, the results were analyzed based on molecular bands and continuum radiation. The model formulations include a nitramine propellant, a double‐base propellant and a composite propellant. Applied were rapid‐scanning filter wheel spectrometers for the wavelength region from 1.2 μm to 14 μm with a time resolution of 50 spectra/s and a wavelengths resolution of 1% of actual wavelength. The UV/VIS wavelengths region was recorded by an OMA system with wavelength resolution of 0.1 nm and 1 nm and time resolution of 10 spectra/s. Molecular bands of water and carbon dioxide dominate in the near infrared and infrared. Depending on composition, continuous radiation indicates particles in the rocket exhaust. A code was developed to calculate molecular bands and continuous radiation using temperature and species distributions found by thermodynamic estimation to obtain the radiance of the plume. Comparison with experimental data delivered plume temperatures.
Size Effect and Detonation Front Curvature
Authors: Souers P. Clark
Published: May 2005

A simple theory relates the size effect (decrease of the detonation velocity with decreasing radius) of a cylinder with its average sonic reaction zone length, 〈xe〉, i.e. the distance from first reaction to the sonic plane. The size effect is described by

where R0 is the radius, Us and D the detonation velocities at R0 and at infinite size and σ is a function describing the extent of wall motion, which is calibrated using four explosives. In this theory, the cylindrical symmetry imposes a quadratic shape to the detonation front. The lag distance at the edge of the cylinder, L0, is related to the reaction zone length by 〈xe〉 ≈︁ L0. Collected results are presented for 56 measured curvatures on 26 explosives, with reaction zone lengths varying from 0.1 mm to 30 mm.
Ignition of pyrotechnic mixture by means of a laser diode. Part I: Numerical modelling
Authors: Gillard Ph. , Roux M.
Published: May 2005

A numerical model of the heating and ignition of a reactive solid by a laser beam has been developed. A transient, two‐dimensional heat equation was solved numerically using an explicit scheme. A nonlinear source term (Arrhenius equation) complicates the analytical resolution of this type of problem. Laser beam absorption is considered in a few micrometer depth. Influence of depth absorption coefficient is investigated. Influence of laser power density, lasering time and thermal diffusivity on ignition are examined by this model. The developed numerical model has been used to design a laser ignition system for explosive substances. It has been shown that ignition by a 0.6 W laser diode at a fiber optics output is feasible.
Mechanical and Swelling Properties of Copolyurethanes based on Hydroxy‐Terminated Polybutadiene and its hydrogenated analog
Authors: Sekkar V. , Krishnamurthy V. N. , Jain S. R.
Published: May 2005

Copolyurethane networks based on Hydroxy‐Terminated Polybutadiene (HTPB) and Hydrogenated HTPB (HHTPB) have been synthesized using toluene diisocyanate as curing agent. Addition of HHTPB results in enhancement of properties, such as tensile strength and modulus, at nearly the same elongation values. It is possible to generate urethane networks with similar modulus and tensile strength with widely varying elongation values and vice versa by jointly altering the comonomer ratio, and the r (NCO/OH equivalent ratio) value. Dynamic mechanical studies have been made to determine the storage and loss moduli, and their variations with temperature. Solid propellant formulations processed with the copolyurethanes have been characterized for their mechanical strengths and burn rates.
Evaluation of a New Primary Explosive: Nickel Hydrazine Nitrate (NHN) complex
Authors: Shunguan Zhu , Youchen Wu , Wenyi Zhang , Jingyan Mu
Published: May 2005

NHN is a thermally and hydrolytically stable solid, easily prepared from available raw materials. Its preparation liquor can be used repeatedly, which means no waste‐water pollution in industrial manufacture. NHN is not sensitive to impact, friction, or electrostatic charge, but is more sensitive to flame. It is demonstrated that NHN is suitable as a replacement for lead azide as an intermediate charge in commercial detonators.
Flamespreading during Base Ignition of Propellant Charge: Theoretical and experimental studies
Authors: Jaramaz Slobodan
Published: May 2005

In the paper theoretical modeling of flamespreading through granular propellant charge during base ignition is given. The theoretical model includes the balance equations for the gas and solid phase, as well as necessary constitutive laws. The stable convergent numerical procedure for solution of the system of equations is developed. This procedure is included in computational program FSPC (Flame‐spreading through Propellant Charge). The program FSPC enables investigations of influence of ignition material, physical and chemical characteristics of propellant and propellant charge loading density on the flamespreading process. The experimental investigations by an especially designed apparatus are performed. The verification of the theoretical‐numerical access through the comparison with the experimental data (pressure vs. time and locations, flamespreading velocity, propellant grains displacements) is carried out. The entire access makes possible more successful solutions of many interior ballistics problems.
Flexibility of the DNA‐binding domains of trp repressor
Authors: Lawson Catherine L. , Zhang Rong‐guang , Schevitz Richard W. , Otwinowski Zdzislaw , Joachimiak Andrzej , Sigler Paul B.
Published: May 2005

An orthorhombic crystal form of trp repressor (aporepressor plus L‐tryptophan ligand) was solved by molecular replacement, refined to 1.65 Å resolution, and compared to the structure of the repressor in trigonal crystals. Even though these two crystal forms of repressor were grown under identical conditions, the refined structures have distinctly different conformations of the DNA‐binding domains. Unlike the repressor/aporepressor structural transition, the conformational shift is not caused by the binding or loss of the L‐tryptophan ligand. We conclude that while L‐tryptophan binding is essential for forming a specific complex with trp operator DNA, the corepressor ligand does not lock the repressor into a single conformation that is complementary to the operator. This flexibility may be required by the various binding modes proposed for trp repressor in its search for and adherence to its three different operator sites.
Molecular interactions in protein crystals: Solvent accessible surface and stability
Authors: Islam Suhail A. , Weaver David L.
Published: May 2005

The accessible surface areas of 58 monomeric and dimeric proteins, when measured in the crystalline environment, are found to be simply related to molecular weight. The loss of accessible surface when the proteins go from a free to their crystalline environment is well defined, implying that the hydrophobic interaction, which has been found to contribute to protein folding and stability in living systems, also contributes to protein crystal stability.
Acid helix‐turn activator motif
Authors: Zhu Qing‐Lin , Smith Temple F. , Lathrop Richard H. , Figge James
Published: May 2005

A common sequence/structural motif pattern has been identified within the steroid/thyroid hormone receptors and other transcriptional activators using a new massively parallel symbolic learning assistant computer system. The pattern appears nearly diagnostic of transcription activation, including relative activation strength, among nuclear and DNA‐binding prokaryotic proteins. In cases where mutation/deletion/chimeric studies have identified the activation domain, the pattern matches within that domain. These facts and the nature of the pattern itself strongly support the idea that the patterned domain is directly involved in a protein‐protein transcription activation interaction.
Conformational and helicoidal analysis of the molecular dynamics of proteins: “Curves,” dials and windows for a 50 psec dynamic trajectory of BPTI
Authors: Swaminathan S. , Ravishanker G. , Beveridge David L. , Lavery Richard , Etchebest Catherine , Sklenar Heinz
Published: May 2005

A new procedure for the graphic analysis of molecular dynamics (MD) simulations on proteins is introduced, in which comprehensive visualization of results and pattern recognition is greatly facilitated. The method involves determining the conformational and helicoidal parameters for each structure entering the analysis via the method “Curves,” developed for proteins by Sklenar, Etchebest, and Lavery (Proteins: Structure, Function Genet. 6:46–60, 1989) followed by a novel computer graphic display of the results. The graphic display is organized systematically using conformation wheels (“dials”) for each torsional parameter and “windows” on the range values assumed by the linear and angular helicoidal parameters, and is present in a form isomorphous with the primary structure per se. The complete time evolution of dynamic structure can then be depicted in a set of four composite figures. Dynamic aspects of secondary and tertiary structure are also provided. The procedure is illustrated with an analysis of a 50 psec in vacuo simulation on the 58 residue protein, bovine pancreatic trypsin inhibitor (BPTI), in the vicinity of the local minimum on the energy surface corresponding to a high resolution crystal structure. The time evolution of 272 conformational and 788 helicoidal parameters for BPTI is analyzed. A number of interesting features can be discerned in the analysis, including the dynamic range of conformational and helicoidal motions, the dynamic extent of 2° structure motifs, and the calculated fluctuations in the helix axis. This approach is expected to be useful for a critical analysis of the effects of various assumptions about force field parameters, truncation of potentials, solvation, and electrostatic effects, and can thus contribute to the development of more reliable simulation protocols for proteins. Extensions of the analysis to present differential changes in conformational and helicoidal parameters is expected to be valuable in MD studies of protein complexes with substrates, inhibitors, and effectors and in determining the nature of structural changes in protein–protein interactions.