bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnesium chloride supported high‐mileage catalysts for olefin polymerization. IV. FTIR and quantitative analysis of modifiers in the catalysts
Authors: Chien James C. W. , Wu Jiun‐Chen , Kuo Chi‐I.
Published: May 2005

Fourier transform infrared (FTIR) spectra were obtained for a typical MgCl2‐supported, high‐mileage catalyst for propylene polymerization. When ball‐milling MgCl2 with ethyl benzoate (EB), the latter is incorporated into the support (I) by Lewis acid‐base complexation involving both oxygen atoms of the ester. Reaction of (I) with p‐cresol (PC) resulted in a material (II) that contains all the characteristic IR bands of PC. The reaction of (II) that contains all the characteristic IR bands of PC. The reaction of (II) with AlEt3 (TEA) resulted in (III) whose spectrum supports the reaction observed by product analysis and NMR spectroscopy. There was no evidence of any reaction between TEA and EB. Further reaction of (III) with an excess of TiCl4 caused substantial removal of the p‐cresol moiety as shown by the diminution of its characteristic bands. Finally, activation with 3TEA‐1MT (methyl‐p‐toluate) complexes gave spectra that revealed the presence of MT in the activated catalyst without any visage of p‐cresol moiety. The nondestructive FTIR method, however, is not quantitative. Quantitative analysis of the organic components in the support materials (I), (II), and (III) and the catalysts was accomplished by hydrolysis of the inorganic components, extraction with ether, and analysis by gas chromatography. The results are in good agreement with composition deducted from elemental analysis and substantiate the FTIR conclusions.
Determination of composition distribution of acrylonitrile‐styrene copolymers by thin‐layer chromatography
Authors: Ogawa Toshio , Ishitobi Wataru
Published: May 2005

Determination of chemical composition distribution of acrylonitrile‐styrene copolymers was carried out by thin‐layer chromatography (TLC). A mixture of benzene and methyl ethyl ketone gave the most suitable calibration curve of Rf values versus acrylonitrile (AN) contents, where a concentration gradient technique was applied for development. Average AN contents obtained by TLC are coincident with those found by elemental analysis. The copolymers extracted from ABS resins are sufficiently arranged in the order of breadth of composition distribution by using the data from TLC. The agreement between the composition distribution curve and that from the theory of copolymerization is good.
Cation binding properties of crown ether‐modified polyethylenimines
Authors: Anzai Jun‐Ichi , Sakata Yoko , Suzuki Yasuhiro , Ueno Akihiko , Osa Tetsuo
Published: May 2005

Crown ether‐modified polyethylenimines (PEI‐CR) were prepared to elucidate their cation binding efficiency and selectivity by liquid‐liquid and solid‐liquid extraction methods. With alkali metal cations it was found that polyethylenimines containing benzo‐15‐crown‐5 moieties (Ia and Ib) extracted all cations examined more efficiently than their monomeric analogs, especially in the cases of K+ and Rb+ cations. The solid‐liquid extraction revealed clearly that the polymers complexed with K+ and Rb+ cations according to a 1:2 cation‐to‐crown stoichiometry. The high selectivities of the polymers for K+ and Rb+ were interpreted in terms of the favourable conformation of the polymer chain for the formation of intramolecular 1:2 complexes. On the contrary, these polymers bound alkali earth cations less effectively with low selectivities.
Charge mosaic membrane with a microstructure of poly(styrene‐b‐4‐vinylpyridine)
Authors: Ishizu Koji , Inagaki Katsumi , Fukutomi Takashi
Published: May 2005

Well defined AB and BAB type poly[styrene(ST)‐b‐4‐vinylpyridine(4VP)]s were prepared by anionic living polymerization in tetrahydrofuran (THF) at −78°C. Casting AB and BAB type poly(ST‐b‐4VP)s with a composition of about 50 mol% PST from 1,1,2‐trichloroethane (TCE) produced specimens with lamellar microdomain structures. Quaternization of P4VP and sulfonation of PST domains (lamellar and spherical structures), accompanied by each domain fixing, were carried out under various reaction conditions. The piezodialysis of the prepared charge mosaic membrane with its lamellar microdomain structure was measured from a sodium chloride (NaCl) aqueous solution. The results are discussed in some detail.
Dilute solution properties of branched polymers
Authors: Kim Jong Ryul , Ree Taikyue
Published: May 2005

For calculating the ratio of the intrinsic viscosities of branched and linear polymers of the same molecular weight, [η]B/[η]L, a new theory taking into account the excluded volume effect is presented. By using the modified Flory equation, the excluded volume effect of branched polymers is predicted with the aid of the first‐order perturbation theory. The linear expansion factor αs is converted to the hydrodynamic expansion factor αη by using the Kurata‐Yamakawa theory. Our calculated results, i.e., [η]B/[η]L and 〈s2〉B/〈s2〉L, agree well with experiment for various type branched polymers, i.e., randomly branched and comb‐shaped polymers of poly(vinyl acetate).
Synthesis and characterization of crosslinked polydiacetylene and its two‐component interpenetrating polymer networks
Authors: Ika Prasad V. S. , Frisch Harry L. , Frisch Kurt C.
Published: May 2005

The synthesis of crosslinked polydiacetylenes and its two‐component interpenetrating polymer networks (IPNs) was carried out utilizing its polar and flexible substituent groups. Polydiacetylenes were crosslinked by the formation of allophanate linkages utilizing urethane groups in the substituent groups of the polydiacetylenes. Elemental analysis, DSC, TMA, solvent resistance, and IR spectra are presented as evidence for the formation of crosslinked polydiacetylenes. IPNs of polydiacetylenes and an epoxy resin (diglycidyl ether of bisphenol A) were synthesized by using simultaneous and sequential methods of synthesis. A study of phase morphology of the simultaneous and sequential IPNs was carried out using electron microscopy, TMA, and DSC.
Model reactions for crosslinking polydiacetylene materials
Authors: Ika Prasad V. S. , Frisch Harry L. , Frisch Kurt C.
Published: May 2005

A series of reactions are presented which allowed us to crosslink polydiacetylenes containing carbamate groups in the side chain without attacking the triple bond. These reactions involved syntheses of carbamates and allophanates from butyl alcohol and phenyl isocyanate with metal and tertiary amine catalysts using a model compound, 2,4,7,9‐tetramethyl‐5‐decyn‐4,7‐diol. Elemental analysis, IR and UV spectroscopy, and high performance liquid chromatography (HPLC) were used as analytical tools. Metal catalysts were found to favor the formation of allophanates in higher yields and purity as compared to tertiary amine catalysts.
Polymer catalysts. X. Vanadium complexes of bipyridine‐based polyureas for epoxidation of alkenes
Authors: Zhang Keda , Kumar G. Sudesh , Neckers D. C.
Published: May 2005

In this article we report on the epoxidation of olefins with hydroperoxides in the presence of a polymer‐anchored vanadium catalyst. Incorporation of vanadium (V) into polar, bipyridine‐based polyureas and the evaluation of the activity and selectivity of the catalyst were investigated.
Polymerization of surface‐active monomers. I. Micellization and polymerization of higher alkyl salts of dimethylaminoethyl methacrylate
Authors: Nagai Katsutoshi , Ohishi Yoshiyuki , Inaba Hiroshi , Kudo Shuichi
Published: May 2005

Micellization of cationic salts of dimethylaminoethyl methacrylate (DMAEMA) quaternized with n‐alkyl bromides such as octyl, lauryl, myristyl, and stearyl bromide and their polymerizations were investigated. The critical micelle concentration (cmc) in water at 25°C was determined by electrical conductivity and dye(azobenzene) solubilization methods and the relation log(cmc) = 1.46–0.31N was obtained, where cmc is in mmol L−1 and N corresponds to carbon number of alkyl bromides used for the monomer preparations. All of these monomeric salts exhibited a high radical polymerizability in water and benzene. The polymerizations in water appeared to proceed with a higher rate with increasing a chain length of the alkyl moiety of the monomers and those in benzene gave the polymers with a remarkably high viscosity. The rate of polymerization of lauryl bromide salt in anisotropic solutions (in water and benzene) was exceedingly fast as compared with that in isotropic solution(in acetonitrile). All of the polymers obtained here were insoluble in water. Solubility characteristics of these monomers and polymers in other solvents were also presented. The reduced viscosity, in dimethylformamide and methanol, of poly(lauryl bromide salt) prepared in water increased with dilution but that for the polymer obtained in benzene exhibited an inverse concentration dependence. Some discussions were made on the peculiarities of the polymerizations of these monomers and the resulting polymers.
Extended Phase‐Doppler System for Characterization of Multiphase Flows
Authors: Naqwi Amir , Durst Franz , Liu Xiaozhi
Published: May 2005

An extended phase‐Doppler anemometry (PDA) system is described, which allows the user to measure the refractive index of spherical particles, in addition to their velocity, diameter and concentration. The extended PDA system incorporates two additional detectors on the receiving side. Each particle generates four Doppler signals. Phase shifts between two pairs of signals are recorded. The ratio between two measured values of phase shifts is a function of the particle refractive index. The phase ratio is shown to be fairly independent of particle velocity or diameter.

Calculations based on Mie scattering theory demonstrated the feasibility of the concept. Measurements with monosize droplets of glycerine‐water mixture, covering the refractive index range 1.33–1.44, were used to verify the theoretical predictions. The instrument was also tested with spray flows.

It is also shown how the phase‐Doppler technique may be used to distinguish between reflecting and refracting particles. This means that the extended phase‐Doppler system may be employed to recognize particle material, and also to measure locally particle velocities, sizes and concentrations, in a multiphase flow with several transparent dispersed phases and one dispersed phase consisting of reflecting particles.
Shape Characterization of Crystals and Crystal Agglomerates
Authors: Riebel Ulrich , Kofler Volker , Löffler Friedrich
Published: May 2005

Crystals and crystal agglomerates exhibit a number of specific shape features which evolve in close relation to the conditions of growth and agglomeration. Hence the quantitative evaluation of these shape features by adequately defined shape parameters can serve to obtain a deeper insight into the mechanisms and kinetics of crystal agglomerate formation and to quantify more precisely the quality of crystallization products.
Hierarchical Properties of Particle Shape for the recognition of powdered materials
Authors: Bonifazi Giuseppe , Massacci Paolo , Patrizi Giacomo
Published: May 2005

Particle shape recognition procedures can be used to determine constituent materials. The problem of recognizing the association between the shape and mineralogical composition of a particle, resulting from comminution of a raw ore, is of great interest.

An algorithm is presented and computational results are given for the classification of particles of iso‐proportional constituents. In this way, the washability function of a set of particulate raw ores can be estimated by taking into account only the contour of the particles. This classification procedure is useful when there are difficulties in the estimation of some relevant properties such as specific gravity or magnetic susceptibility.

The procedure has been successfully applied to the recognition of the mineralogical composition of particles resulting from the comminution of a chromite ore and to the classification of particles in iso‐composition classes.
Particle Size Distribution of Inorganic Colloidal Dispersions: A comparison of different techniques
Authors: Delgado Angel , Matijevié Egon
Published: May 2005

The particle size distributions of a latex and of four different inorganic colloidal systems, consisting of spherical particles suspended in aqueous solutions, have been evaluated by three techniques: electron microscopy (EM, scanning and/or transmission), classical light scattering (CLS, polarization ratio method), and photon correlation spectroscopy (PCS, commercial instrument). Both light scattering techniques appear to be exceedingly sensitive to even a relatively small level of aggregation. Thus, the effect of treating the dispersions by ultrasonic energy was tested in order to establish the best experimental conditions. While a shorter sonication results in a minimum or constant value for the average particle diameter (or the polydispersity of the suspension), longer times may promote reaggregation of particles. Good correlation of the results by different light scattering techniques was found as long as the conversion to number averages of the PCS data involved the proper corrections for polydispersity. The agreement with the EM depended on the chemical nature of the dispersed particles; i.e., drying and exposure to the electron beam greatly affected the histograms in some cases.
Particle Sizing by Photon Correlation Spectroscopy Part I: Monodisperse latices: Influence of scattering angle and concentration of dispersed material
Authors: De Jaeger Nicolas , Demeyere Hugo , Finsy Robert , Sneyers Rik , Vanderdeelen Jan , van der Meeren Paul , van Laethem Marc
Published: May 2005

The possibilities and limitations of Photon Correlation Spectroscopy as a practical tool for particle sizing are revisited. In a first step, well characterized monodisperse polystyrene latices with particle sizes ranging from about 30 nm to about 2 μm were examined in five different industrial and academic laboratories. Particular attention was paid to the effect of particle concentration and scattering angle. It turned out that for a particle diameter less than 0.5 μm reliable particle sizes can be obtained. In the range of 0.5 to 1 μm this was only possible within a very narrow range of concentration of dispersed material. For the largest size investigated (about 2 μm) the PCS measurements were less reliable which was reflected in a considerable variation of the results.
A technique for measuring contact angles at particles
Authors: Bröckel Ulrich , Löffler Friedrich
Published: May 2005

The behavior of particles at the phase transition between a gas or liquid and another liquid phase may be characterized by the so‐called wetting (or contact) angle. In contrast to plane surfaces, which allow such measurements to be conducted relatively easily, the determination of the wetting angle between a liquid and the surfaces of fine particles demands extensive preparative measures. The method adopted by Heertjes and Kossen [12] for example, involves compressing a tablet from the powder in question, from which the wetting angle may then be derived. The compression process naturally modifies the superficial structure of the particles, and hence their wetting characteristics. This paper describes a preparation technique with which the wetting angle between a liquid and fine particles can be derived without modifying the surface texture. This involves coating and adhering a monolayer of the powder on a carrier plate and measuring the composite wetting angle of the particles and the adhesive film. The specification of the adhesive's wetting angle and areal porosity of the carrier medium allows the wetting angle of the given powder subsequently to be evaluated.
Asbestos Fiber Concentrations Resulting from the Installation, maintenance and removal of vinyl‐asbestos floor tile
Authors: Lundgren Dale A. , Vanderpool Robert W. , Liu Benjamin Y. H.
Published: May 2005

This paper presents the results of a systematic study to measure the exposure to asbestos fiber concentrations associated with occupational use of asbestos‐containing floor tile. Specifically, air measurements were made during floor tile installation, maintenance and removal. The procedures for these tests are outlined and the results of the air sampling and analysis are discussed.
Light Scattering Applied to LDA and PDA Measurements. Part 1: Theory and numerical treatments
Authors: Naqwi Amir A. , Durst Franz
Published: May 2005

Mathematical tools are provided for computation of the scattered field produced by a spherical particle moving through the region of interference of two crossing laser beams. This formulation is readily applicable to laser Doppler and phase Doppler anemometers (PDAs). In particular, the geometry of PDAs is treated in the most general terms. The cases of very large and very small particles are considered in detail. In the first part the theory underlying the computer code STREU, which was produced during the present work, is discussed and relevant mathematical formulations are presented. Also, graphical tools are provided for the convenience of the designers.

In Part 2 the utility of the computer code is demonstrated with the help of examples in the area of phase Doppler anemometry. It is shown that the phase Doppler technique may be used for sizing of submicron particles in addition to large particles. Measurement of particle refractive index, in addition to the diameter, is also made possible.
Measurement of Polydisperse Colloidal Suspensions with quasielastic light scattering
Authors: Madani Hassan , Kaler Eric W.
Published: May 2005

The measurement of polydisperse populations of colloidal particles with quasielastic light scattering (QLS) is a common and dangerous practice. Here intensity autocorrelation functions with different linewidth distributions are simulated. The simulated data are treated with the histogram and exponential sampling methods and the results are contrasted with the results of the Laplace inversion routine of Provencher. All methods work well in calculating the size distribution from noise‐free correlation functions. In analyzing noisy data the methods may produce results that bear no relation to the true size distribution. The histogram method fails to determine size distributions from noisy simulated and real correlation functions. The exponential sampling method gives a qualitative measure of the size distribution when the required resolution does not exceed the limitations set by noise theory. Provencher's routine extracts smooth unimodal distributions very accurately even from noisy correlation functions, but determination of bimodal distributions may be unreliable. The importance of taking data at many scattering angles is emphasized and experimentally determined size distributions of samples of polystyrene latex spheres measured at multiple scattering angles are presented.
Regularized Inversion of the Laplace Transform: Accuracy of analytical and discrete inversion
Authors: Ross Douglas A. , Dhadwal Harbans S.
Published: May 2005

Dynamic light scattering is a technique used for the optical determination of a colloidal particle size distribution. A simple procedure, based on a trapezoidal model for the linewidth distribution function, is given for obtaining a constrained regularized inversions of correlation data obtained in dynamic light scattering experiments, and estimating the accuracy of such inversions. Based on the eigenfunction decomposition of the Laplace integral equation, error bars, which are directly related to the accuracy of the correlation data, may be placed on both analytical and discrete inversions. By using a regularization procedure, and a nonnegativity constraint, problems with statistical noise in data may be handled effectively.
Control and Use of a Miniaturized Droplet Generator
Authors: Blümcke Erich , Eickhoff Heinrich , Hassa Christoph
Published: May 2005

A miniaturized droplet generator with some new features, working on the principle of laminar liquid jet instability and break‐up was designed. The instrument has been used to study the dispersion of monosized droplets in a turbulent swirling flow, exhibiting the main features of combustion chamber flows of modern gas turbines.

The operating range of the generator was evaluated by phase‐Dopper anemometry (PDA). It was demonstrated that the device also works in some metastable operating modes, producing coherent droplet streams with very small standard deviations for drop size and drop velocity. Special attention was directed to the reliability of the device and to the control of drop size. The PDA measurements showed that, in contrast to the evaluated optimum excitation frequency, the drop size cannot be determined from the orifice diameter.
Etude de la rupture des poudres pour armes
Authors: Benhaim P. , Paulin J. L. , Zeller B.
Published: May 2005

Pendant la phase d'allumage des charges propulsives pour munitions destinées aux armes à tube, des grains de poudre sont accélérés et compactés brutalement contre le culot du projectile. Des ruptures de grains en résultent qui peuvent induire des pics de pression dangereux.

Les critères de rupture ont été étudiés expérimentalement par projection de grains de poudre contre une plaque d'acier. Les paramètres étudiés sont:

la température,

la géométrie des grains,

la composition.

Il a été observé:

une probabilité non négligeable de rupture des grains à la température ordinaire pour des vitesses d'impact aussi basses que 30 m/s,

une augmentation de la fragilité aux basses températures,

un mode de rupture dépendant de la température, de la vitesse d'impact et de la composition de la poudre, et induisant des effets différents qui ont été mis en évidence par tirs en bombe manométrique sous haute pression.
Studies on the Combustion of Solid Hydrazones with Nitric Acid
Authors: Jain S. R. , Krishna P. M. M. , Pai Verneker V. R.
Published: May 2005

The heats of ignition and volumes of the gases released on combustion of various solid hydrazones with nitric acid as oxidizer, have been determined. The experimental values when compared with those calculated indicate incomplete combustion. Both, the heats of ignition and the volumes of gases generated appear to depend upon the substituent in the benzene ring of the hydrazone carbon atom. The électron releasing groups are found to enhance these combustion parameters in the case of phenylhydrazones whereas no such trend was noticed in the case of dimethylhydrazones. The combustion products of these systems have been analyzed by a mass spectrometer. The major products are found to be N2, CO, NO, H2O, CO2 and N2O along with trace amounts of O2.
A simple viscometric test for number average and weight average molecular weight of 12.6% N pyro nitrocellulose
Authors: Bullock D. J. , Cosgrove J. D. , Head B. C. , Lewis T. J. , Marshall E. J. , Wason D. , Watson B. M.
Published: May 2005

In the poor solvent acetone/ethanol the viscosity of a 3% solution of 12.6% N pyro nitrocellulose is found to be related to the geometric mean of the number average and weight average molecular weights. The fractional increase in the viscosity of such a solution on the addition of lead ß‐resorcylate is a function only of number average molecular weight. Once calibration has been made against osmotic pressure measurements and intrinsic viscosity, both number and weight average may be measured rapidly with an accuracy which is no less than that of the osmotic pressure and intrinsic viscosity measurements themselves.
The Ammonium Nitrate‐Potassium Nitrate System
Authors: Cady H. H.
Published: May 2005

A portion of the binary phase diagram for the system ammonium nitrate‐potassium nitrate has been determined from − 55 °C to 185 °C. Results are presented for the ammonium‐nitrate‐rich end of the system up to 30 wt% potassium nitrate.
Une condition de surface critique pour l'amorçage par onde de choc des explosifs solides
Authors: Moulard H.
Published: May 2005

Des cibles en hexolite sont impactées par de petits projectiles en acier. Les expériences ont consisté à déterminer la vitesse d'impact critique pour la transition choc‐détonation. Le paramètre étudié est la géométrie du projectile (forme, dimensions). Nos résultats expérimentaux montrent que la compréhension de la sensibilité des explosifs solides nécessite d'introduire un nouveau concept de surface critique. D'autre part, des expériences d'amorçage par plaques volantes montrent clairement que la non‐prise en compte de ce nouveau paramètre de contrôle conduit à des valeurs surestimées de l'énergie critique nécessaire pour la transition choc‐détonation.
Alternative Procedures for Preparing HMX
Authors: Siele V. I. , Warman M. , Leccacorvi J. , Hutchinson R. W. , Motto R. , Gilbert E. E. , Benzinger T. M. , Coburn M. D. , Rohwer R. K. , Davey R. K.
Published: May 2005

Three new procedures are described for preparing HMX from hexamine, each involving acetylation followed by nitrolysis. One of these — involving DADN as intermediate — gives a better yield of HMX than the established Bachmann process on the basis of hexamine and acetic anhydride, but involves the use of sulfuric and polyphosphoric acids, which are not required in the Bachmann approach. It was shown that DADN can be produced rapidly and continuously on a pilot scale in good yields, and that spent acid recovery involves no unusual problems.
Etude des conditions d'initiation de la pentrite (PETN) par spectrométrie raman ultra‐rapide
Authors: Tailleur M. H. , Cherville J.
Published: May 2005

La diffusion Raman ultra‐rapide permet d'étudier les phénomènes très brefs qui président à la génération de la détonation dans des explosifs secondaires nitrés. D'après une étude théorique précédente, il existe pour ces explosifs une liaison de type RNO2 par où débute la réaction de décomposition explosive sous choc. Cette étude théorique a été vérifiée expérimentalement sur deux de ses conclusions: le changement de phase de la pentrite et les modifications de structure électronique affectant l'une des liaisons ONO2 sous choc. Pour ce faire, une étude de la pentrite à l'état monocristallin a été réalisée par spectrométrie Raman classique en vue d'une attribution complète du spectre. Il a été en même temps observé des éclatements des modes polaires du fait de l'absence de centre d'inversion dans la maille. L'étude expérimentale entreprise par la suite a nécessité une mise au point du montage Raman avant de conduire aux résultats montrant, outre de faibles déplacements de fréquence, d'importantes variations d'intensité de quelques raies pour une certaine pression de choc.
New adducts of octahydro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine (HMX)
Authors: Selig W.
Published: May 2005

A new series of relatively stable adducts of octahydro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine (HMX) with derivatives of pyridine‐N‐oxide were prepared. In addition, relative stable new adducts of HMX were prepared with 5‐membered, 6‐membered, and condensed‐ring heterocyclic compounds. Most of the adduct‐forming compounds (AFC's) contain an oxygen and/or nitrogen heteroatom, while several contain a sulfur heteroatom. Most of the adducts are equimolar with HMX; however, several contain 2 moles of AFC per mole of HMX and other ratios of AFC:HMX. Some properties of the new adducts are presented.
Explosion thermique (cook off) des propergols solides
Authors: Kent R. , Rat M.
Published: May 2005

Le document que nous présentons fait le point sur les premiers travaux effectués par le Centre de Recherches du Bouchet de la SNPE, sur les phénomènes d'explosion thermique, destinés à étudier la stabilité des propergols solides.

Ces travaux nous ont permis de mettre au point une méthodologie d'essais pour mesurer assez précisément, les valeurs des constantes cinétiques et physiques des propergols et d'établir, pour des blocs pleins et cylindriques de propergol composite aluminisé, un modèle empirique.

Ce modèle empirique (calqué sur le modèle théorique de Zinn et Mader(1) qui, expérimentalement, ne s'adapte qu'aux explosifs) est susceptible de prévoir, à partir d'un nombre limité d'expériences, les températures critiques et les temps d'induction, quelle que soit la taille des blocs de propergol.
Processing Characteristics of Gun Propellants
Authors: Baker F. S. , Carter R. E.
Published: May 2005

Using especially modified torque and capillary extrusion rheometers the rheological behaviour of a typical triple‐base gun propellant has been examined as a function of such processing variables as temperature, solvent content, time taken to incorporate, filler content and filler shape. Propellant doughs flow according to the law \documentclass{article}\pagestyle{empty}\begin{document}$ \sigma -\sigma _0 = {\rm K}\dot \gamma ^{\rm n} $\end{document} where σ is the shear stress applied to the dough to maintain a shear rate of γ, σ0 is the yield stress at which flow commences, K is the consistency index and n is the flow behaviour index. Variations in these constants as a function of the above mentioned variables are presented and their implications discussed. Resultant changes in the physical properties of the dried extruded propellant also are monitored.
A Parametric Study of the Synthesis of 2,2′,4,4′,6,6′‐Hexanitrostilbene from trinitrotoluene and sodium hypochlorite
Authors: Golding P. , Hayes G. F.
Published: May 2005

The synthesis of 2,2′,4,4′,6,6′‐hexanitrostilbene by the action of alkaline sodium hypochlorite on 2,4,6‐trinitrotoluene has been studied. The effects of time, temperature, pH, solvent composition and mode of TNT addition on the yield of HNS are discussed. The reaction, usually referred to as the Shipp synthesis, is shown to be highly susceptible to variations in process conditions, particularly base and water concentrations. The conversion of 2,4,6‐trinitrobenzyl chloride, an intermediate in the Shipp reaction, to HNS has also been examined.
Impact Sensitivity of γ‐Irradiated HMX
Authors: Miles M. H. , DeVries K. L. , Britt A. D. , Moniz W. B.
Published: May 2005

Impact of thin layers of HMX at room temperature and near liquid nitrogen temperature were performed. Polycrystalline powders of HMX irradiated with 7.5 megarad in evacuated tubes at liquid nitrogen temperature showed significant enhanced sensitivity. With 10‐megarad irradiations of HMX in evacuated tubes at liquid nitrogen temperature frequent spontaneous explosions in HMX have occurred. ESR measurements on impacted HMX and RDX powders at room temperature and near liquid nitrogen temperature at energies of less than 1 kg · m have not produced detectable mechanically generated free radicals. A significant increase in sensitivity of vacuum irradiated HMX was observed but efforts to correlate this with the dominant frozen‐in NO2 γ‐radical concentration were unsuccessful. It is suggested that the NO2 radical is a chain terminating radical in explosive systems.
Contribution à l'étude de la thermolyse des esters nitriques
Authors: Amer A. A.
Published: May 2005

Par utilisation des moyens comme la spectrographie infrarouge et la résonance magnétique nucléaire, combinée éventuellement avec la chromatographie sur couche mince, on a pu identifier les produits condensées de la décomposition thermique des esters nitriques, puis on propose une série de réactions aboutisant aux produits observés.
Détermination par ultra‐sons des Propriétés dynamiques d'un propergol double base
Authors: Martin Ch. , Lebois J.
Published: May 2005

Des mesures de vitesse et d'atténuation des ultra‐sons (0,4 MHz à 2,25 MHz), à la fois en ondes longitudinales et en ondes transversales, ont été effectuées par transmission par contact sur un propergol homogène double base. Malgré la forte absorption présentée par ce matériau, on a réussi à faire des mesures de ‐40°C à + 10°C.

A partir de ces données, les composantes réelles et imaginaires de toutes les constantes élastiques complexes L*, G*, E*, K* et v* du propergol ont été calculées, et leur évolution étudiée en fonction de la température. Les courbes maîtresses correspondantes ont été tracées et concordent bien avec les autres portions de celles‐ci obtenues à plus basses fréquences par vibrations mécaniques. Le coefficient de Poisson v' varie, dans le domaine étudié, entre les valeurs limites de 0,33 et 0,83. Un point de transition à + 10°C a été trouvé à ces hautes fréquences.
Substituent Pattern Effect in the reaction of dimethyltrinitronaphthalenes with Di‐ and triethylamine
Authors: Buckley E. , Houiellebecq T. F. , Wells C. H. J.
Published: May 2005

The kinetics of the reaction of di‐ and triethylamine with 1,8‐dimethyl‐2,4,5‐trinitronaphthalene (245 TND) have been studied in dimethylsulfoxide and dimethylsulfoxide‐methanol solvent systems and comparison made with data for corresponding reactions involving 1,5‐dimethyl‐2,4,8‐trinitronaphthalene (248 TND). Analysis of the results shows that the formation of a benzyl‐type anion is more facile with 245 TND than with 248 TND. Thus, the former compound has the greater potential for base‐induced coupling to give thermally stable explosive material.
5‐Phenyl‐cyclohexane‐1,3‐dione‐4‐carboxanilide as stabilizer for double base propellant
Authors: Soliman Adly A.‐W. , El‐Damaty A. A.
Published: May 2005

5‐Phenyl‐cyclohexane‐1,3‐dione‐4‐carboxanilide is used as a stabilizer for double‐base propellant and gives good results with the stability tests. The samples were stored for 12 days at 100°C and were extracted by different suitable solvents. The column partition chromatography helped in separation of the different nitro‐derivatives of the 1,3‐diketone stabilizer.
Thermoanalytical studies on CTPB‐NH4ClO4 composite solid rocket propellants
Authors: Prasad M. R. R. , Krishnamurthy V. N.
Published: May 2005

Premature reignition of controllable solid propellant motors, a factor affecting the extinguishment reliability, has been attributed to the first exotherm of NH4ClO4. Detailed studies were made(1) on suppressing the first exotherm of NH4ClO4 with the use of materials like NH4BF4, NH4PF6, (NH4)2TiF6 etc. The present paper deals with the thermal decomposition kinetics of carboxy‐terminated polybutadiene (CTPB)‐NH4ClO4 propellant with NH4BF4 as an additive to suppress the first exotherm of NH4ClO4.

The techniques employed in this study include: differential scanning calorimetry (DSC) for the thermal decomposition studies, and strand‐burner for the measurement of propellant burning rates. DSC experiments were conducted on the propellants at pressures of ambient, 17 kg/cm2 and 40.82 kg/cm2; at a constant heating rate under an inert atmosphere of nitrogen. The burning rate of the propellant samples were determined in the pressure range of ambient to 70 kg/cm2 in an atmosphere of nitrogen.

The burning rates were found to increase with pressure at each of the concentrations of the additive. The decrease in burning rate with the increase in concentration of the additive, at pressures of 35 kg/cm2 and below is attributed to the excess of ammonia formed during the decomposition of both NH4ClO4 and NH4BF4. At pressures above 35 kg/cm2, the increase in burning rate with the increase in concentration of the additive is attributed to the increased concentration of the metal ion (boron) in NH4BF4. These observations are in agreement with those of Mayer(1) et al., and Glaskova(2).
Experimental study of Double‐Base Propellants Combustion Mechanisms
Authors: Duterque J. , Hommel J. , Lengelle G.
Published: May 2005

Experimental results about rb(P) laws of double‐base propellants are presented. The influence of many parameters (calorific potential, fabrication process, additives) is studied. With surface structure examination, we show that the first super‐rate (P < 100 bar) is in relation with the presence of a carbon layer which increases chemical reactions. The second super‐rate (200 bar < P < 400 bar), more physical than chemical, is in relation with the presence of globules (probably PbO) which increase the thermal conductivity near the propellant surface.
Examination of Wax‐Coated RDX by scanning electron microscopy and X‐ray photoelectron spectroscopy
Authors: Cowey K. , Day S. , Fryer R.
Published: May 2005

Scanning electron microscopy (SEM) and X‐ray photoelectron spectroscopy (XPS) have been used to examine the nature and quality of wax‐coated RDX crystals. SEM allows a visual assessment of wax‐coated crystals and comparison of different coating processes. XPS has allowed a semiquantitative determination of the degree of wax coverage by measurement of the carbon to nitrogen photoelectron emissions and calculation of the percentage of wax coverage using a simple mathematical treatment.
Synthesis and explosive properties of 1,3,5‐trinitro‐hexahydropyrimidine (tnp) and 5‐nitroxymethyl‐1,3,5‐trinitro‐hexahydropyrimidine (nmp)
Authors: Ritter H. , Licht H. H.
Published: May 2005

Triple aminoalkylation of nitromethane with formaldehyde and tert‐butylamine resulted in a cyclic Mannich base, the nitrolysis of which gave 1,3,5‐trinitro‐hexahydropyrimidine. Hydroxymethylation and subsequent nitration converted it to 5‐nitroxymethyl‐1,3,5‐trinitro‐hexahydropyrimidine. Both compounds exhibit pronounced explosive properties.
Simplified and Extended Gurney Formulas for Imploding Cylinders and Spheres
Authors: Hirsch E.
Published: May 2005

The usefulness of the Gurney formulas in application to one‐dimensional computer codes for shaped charge design has called for their extention to predict the asymptotic velocities of imploding cylinders. Two different approaches by Chou, Carleone, and Flis on 1981 and by Chanteret on 1983 have led to improvements which were shown to predict correctly two‐dimensional code simulations for unconfined charges. Both works did not lead however to simple formulas which retain the conveniency of the original Gurney formulas. In the work presented, closed form analytical solutions for both the cylindrical as well as the spherical geometries are derived. The solution for each geometry is presented in a way in which the symmetry between the inner liner and the confinement is easily recognized. The relation of each solution to the Gurney formula for asymmetrical sandwich is also obvious. The presented solutions reduce to all the known Gurney formulas for the more simple geometries at the appropriate limits. The accuracy of the predictions by the obtained formulas is limited however when the assumptions of the Gurney model do not describe the real physical situation closely. This happens in general in extreme cases, e.g. when the liners are very light comparing to the explosive mass or when the ratio between the confinement radius and the inner liner radius is very large comparing to unity.
General Kinematical Solution to the Motion of an Explosively Driven Liner
Authors: Hirsch E. , Chou P. C. , Ciccarelli R. D.
Published: May 2005

It is shown that the motion of an explosively driven smooth thin liner, obeys, whenever the material forces are negligible, the following equation:

where V is the liner velocity, ∂Vl/∂t is the time derivative of the velocity component along the liner direction and l is the Lagrangian coordinate measuring the length of the liner contour (formation line). The transformation from the rest to moving coordinate system is calculated, as well as a very accurate approximation to the liner elongation. Under the assumption of an exponential acceleration a closed form for the liner elongation is obtained. The influence of the liner curvature on the projection angle δ is also found. The comparison of the obtained solution with two dimensional Lagrangian code calculations shows a very good agreement. Finally, some predictions of the model are discussed for demonstrating its applicability to various problems.
Differential Pulse Polarographic Analysis of Powders and Explosives
Authors: Asplund J.
Published: May 2005

This investigation demonstrates how mixtures of glycerol trinitrate, diethyleneglycol dinitrate, 2,4‐dinitrotoluene, 2,4,6‐trinitrotoluene, nitroguanidine, dibutyl phthalate, diethyl phthalate, cyclotrimethylene trinitramine (hexogen) and cyclotetramethylene tetranitramine (octogen) in powders and explosives can be analysed by differential pulse polarography. The analysis of, for example, glycerol trinitrate, 2,4‐dinitrotoluene and 2.4,6‐trinitrotoluene in powder is made as a three‐component system with overlapping polarograrns, while the analysis of dibutyl phthalate, nitroguanidine and glycerol trinitrate in powder is made as three independent single component systems.

The polarographic reduction of organic compounds is effected both by the composition of the solvent and its pH value. By careful choice of the experimental conditions it is often possible to obtain sufficiently differing forms of differential pulse polarograms for the various compounds, which can be exploited for analytical purposes. Various water! methanol solutions have been studied to find the mixtures that give the greatest differences in the polarograms. The effect of ammonium acetate and tetramethyl ammoniumbromide as electrolyte has been studied.
Improved Gurney Formulas for Exploding Cylinders and Spheres using “Hard Core” Approximation
Authors: Hirsch E.
Published: May 2005

The final liner velocity predicted by the Gurney formulas for sandwich cylindrical and spherical configurations for very light liners (small M/C values) are (6E)1/2, (4E)1/2 and (10E/3)1/2 respectively. The existance of these differences among the limiting velocity values contradicts the well known fact that the explosive products' escape velocity does not depend on the initial geometry of the explosive when no Mach waves are formed.

An improvement to the Gurney formulas for exploding cylinders and spheres is suggested which corrects this basic inconsistancy. It is based on the observation that light liners are accelerated to their final velocity in a short time getting their kinetic energy mainly from that part of the explosive which is in contact with them. It is shown that by excluding from the explosive mass the inner volume and replacing it with an infinitely hard core the experimentally measured liner velocities for the cylindrical and spherical geometrics are more accurately reproduced. The core radius is found by maximizing the liner velocity, thus getting the fastest transformation of the gas potential energy to kinetic energy which is possible within the model assumptions. The improved formulas predict for the limit of very small M/C the same velocity, (6E)1/2 for all the above mentioned geometries. The comparison of the improved formulas with available experimental data reveals how the accuracy of the Gurney model is limited at the large and the small values of M/C.
Penetration Theory for Inclined and Moving Shaped Charges
Authors: Held M. , Fischer R.
Published: May 2005

An analytical model will be given for the calculation of the dynamic penetration of inclined shaped charges at an arbitrary stand‐off distance and for all possible angles between the shaped charge axis and the axis of the carrier, and for various obliquities of the target plate. The advantage of an analytical model is, estimates of penetration and trends can be established quickly and easily through a variation of shaped charge and target parameters.
Propriétés mécaniques des poudres et explosifs pulvérulents et mode de transition déflagration/détonation
Authors: Samirant M. , Lichtenberger A.
Published: May 2005

Deux modes de transition combustion/déflagration/détonation ont été mis en évidence dans les milieux réactifs poreux fortement confinés dans des tubes d'acier. L'un fait intervenir une transition choc/détonation, par exemple dans une hexocire, l'autre montre une accélération progressive et continue de l'onde de combustion jusqu' à la détonation dans une poudre sphérique double base. Au moyen de jauges à couche de Manganin et de jauges d'extensométrie nous avons suivi la propagation des ondes de compression en avant du front de combustion et nous avons montré que le lit d'explosif est quasi élastique alors que le lit de poudre subit un intense travail mécanique. La différence dans la dissipation d'knergie qui en résulte en avant du front de combustion pourrait être responsable de la différence de comportement entre ces deux milieux réactifs. En modifiant par broyage préalable les propriétés de la poudre sphérique on montre qu'elle peut aussi subir une transition choc/détonation.
Stationary Phase 5. Evaluation of Stationary Phases for HPLC of Explosives
Authors: Den T. G. , Ho K. C. , Lee C. H. , Wang C. B. , Chang T. C. , Chen Y. Z.
Published: May 2005

The retentions of 11 explosives on two commercially RP‐18 and Si 100 stationary phases and one prepared 3‐[9′‐(10′‐methylanthryl)]‐ propylsilane stationary phase (MAPS‐phase) were examined by modified mobile phases. The evaluation of these three stationary phases results as follows:

Most explosives were effectively separated on a column of MAPS‐phase not only with methanol/water (75/25‐85/15) as mobile phase but also with n‐hexane/dichloromethane (75/25) as mobile phase.

Few explosives were effectively separated on a column of RP‐18 with methanol/water (75/25‐85/15) as mobile phase.

The separation of most explosives on Si 100 was achieved only under normal phase condition such as n‐hexane/dichloromethane (75/25) as mobile phase.
Studies on Hypergolicity of Several Liquid Fuels with fuming nitric acids as oxidizers
Authors: Durgapal U. C. , Dutta P. K. , Pant G. C. , Ingalgaonkar M. B. , Oka V. Y. , Umap B. B.
Published: May 2005

Hypergolic or self ignition delays of unsymmetrical dimethylhydrazine (UDMH) and several amine fuels, mixed with three fuming nitric acid oxidizers, have been determined, at room temperature, in a highly sensitive “Cup Test” apparatus. Ignition delay (ID) variations have been studied with respect to the chemical structure of fuel, oxidizer composition, and oxidizer‐to‐fuel (O/F) ratio. Probable preignition reactions and structure‐hypergolicity correlations have been suggested.

Some non‐hypergolic hydrocarbons and petroleum fractions have been hypergolized by addition of UDMH, and ID variations have been studied with respect to UDMH‐content in fuel and catalytic additives (ammonium metavanadate, ammonium dichromate, and cuprous oxide) in the red fuming nitric acid oxidizer (RFNA). Increment in UDMH‐content improves the hypergolicity of fuels towards RFNA. For example, kerosene + UDMH 60:40 blend ignites with RFNA with a remarkably low ID of 6 ms. However, the catalytic effect of the additive in RFNA varies widely with the fuel‐blend composition.
A Modification of the Mott Formula for prediction of the fragment size distribution
Authors: Strømsøe E. , Ingebrigtsen K. O.
Published: May 2005

A modification of the Mot fragmentation formula, accounting for a maximum fragment size, is suggested. Twelve experimental data sets are used to test the goodness of fit of the original and the modified formula. Generally, the modified formula is found to give a better representation of the experimental data, and particularly, the overestimation of the number of very large fragments is avoided.
Effect of High Dynamic Pressure on the Structure of Solids
Authors: Batsanov S. S.
Published: May 2005

The influence of shock waves on crystal macrostructure and its physical and technological consequences are discussed. The size of crystal particles grain corresponding to the transition of solid into amorphous state is estimated. The magnitudes of microstrains in crystals during their grinding are calculated. It is shown that under shock‐wave treatment the grain size and microstrain are usually about 10 times differed from the values in amorphous substances. The possibility of amorphization during chemical interaction under shock compression is shown. Phase transformations with change of stoichiometry under shock waves prove a perspective synthetic method.