bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of polyamides from active 4,4′‐diacylbis‐2‐aryl‐1,3,4‐oxadiazoline‐5‐thiones and ‐ones and diamines under mild conditions
Authors: Saegusa Yasuo , Nakamura Shigeo , Chau Nguyen , Iwakura Yoshio
Published: May 2005

New active bisamides, 4,4′ ‐diacylbis‐2‐aryl‐1,3,4‐oxadiazoline‐5‐thiones and ‐ones having various electron accepting groups in the oxadiazoline units were synthesized, and their reactivities toward diamines were investigated. The polycondensation reactions of the bisamides derived from 2‐aryl‐1,3,4‐oxadiazoline‐5‐thiones with both aliphatic and aromatic diamines occurred rapidly even at room temperature to form high‐molecular‐weight polyamides in quantitative yields. The reactivities of the bisamides having electron accepting groups such as p‐chloro and p‐nitro groups, particularly p‐nitro groups, toward diamines were much higher than that of the corresponding bisamide having no such group. It was also found that reaction conditions such as solvent, monomer concentration, and temperature had a strong influence on the molecular weight of the resulting polyamides. Aminolysis of several benzoyl derivatives of 2‐aryl‐1,3,4‐oxadiazoline‐5‐thiones and ‐ones was also carried out as a model reaction, and the effect of electron accepting groups on the reactivity of these compounds was discussed.
The solubility of cellulose in liquid ammonia/ammonium thiocyanate solution: The effect of composition and temperature on dissolution and solution properties
Authors: Hudson S. M. , Cuculo J. A. , Wadsworth L. C.
Published: May 2005

The dissolution process and some solution properties of cellulose in mixtures of liquid ammonia (NH3) and ammonium thiocyanate (NH4SCN) are discussed. The mole fraction ratio of NH3, NH4SCN, and H2O which dissolve cellulose were determined. The effect of temperature on several solution properties was also examined. The temperature coefficient d In [n]/dT for the limiting viscosity number [n] has a value of −1.58 × 10−2 °C−1. This is considered to be rather large but is, in fact, a common occurrence for almost all cellulose derivatives in solution. The values for the Huggins constant K′ showed no systematic trends with temperature. They did, however, suggest the presence of considerable association of the cellulose in solution. Miscibility results of adding the cellulose solutions to organic liquids are also reported.
Synthesis and characterization of linear high molecular weight poly(amino‐s‐triazine)s
Authors: Wang David Wei , Fisher Michael M.
Published: May 2005

A two‐phase polycondensation reaction was used to prepare high molecular weight linear poly‐(amino‐s‐triazine)s from aminodichloro‐s‐triazines and diamines. These polymers contain a high concentration of melamine‐type units in the polymer backbone. Molded specimens exhibited good mechanical properties and resistance to organic solvents. Dimethyl substitution at the exocyclic amino group led to a significant reduction in indentation resistance, strength, and modulus.
Long‐lived polymer radicals. III. Synthesis of block copolymer by the reaction of living poly(N‐methylacrylamide) radical with some vinyl monomers
Authors: Sato Tsuneyuki , Iwaki Takahiko , Mori Shigeki , Otsu Takayuki
Published: May 2005

N‐Methylacrylamide (NMAAm) was polymerized quantitatively by using di‐tert‐butyl peroxide as photosensitizer to be, for the most part, incorporated in living poly(NMAAm) radical. The living polymer radical reacted effectively with acrylate monomers to yield block copolymer. Longer alkyl chain of the acrylate monomer caused a decrease in the conversion of the second monomer. Methacrylate monomers, such as methyl methacrylate and cyclohexyl methacrylate, showed relatively low reactivities in comparison with acrylates. Styrene exhibited a much lower conversion. The resulting block copolymers showed different thermochromic behaviors in methyl benzoate from that of poly(NMAAm). This is explained on the basis of the difference between refractive indexes of the block copolymers and poly(NMAAm).
Dehydrofluorination of poly(vinylidene fluoride) in dimethylformamide solution: Synthesis of an operationally soluble semiconducting polymer
Authors: Dias Anthony J. , McCarthy Thomas J.
Published: May 2005

The reaction of poly(vinylidene fluoride) with several different bases in dimethylformamide solution yields dehydrofluorinated products with conjugated polyene structures. The extent of elimination can be controlled by varying the amount of added base. The structural properties of dehydrofluorinated materials depend on the base used. Polymer films cast from DMF solution exhibit electronic conductivity upon iodine doping; the conductivity is also a function of the base used.
Surface modification of polypropylene with CF4, CF3H, CF3Cl, and CF3Br plasmas
Authors: Strobel Mark , Corn Stewart , Lyons Christopher S. , Korba Gary A.
Published: May 2005

ESCA and contact angle measurements were used to characterize the surfaces of polypropylene and glass substrates exposed to CF4, CF3H, CF3Cl, and CF3Br plasmas. The use of both organic and inorganic substrates allowed clear distinction between treatments which led to plasma polymerization and treatments which caused grafting of functional groups directly to the substrate surfaces. CF4 plasmas were the only treatments studied which fluorinated polypropylene surfaces directly, without the deposition of a thin, plasma‐polymerized film. CF3H polymerized in a plasma, while CF3Cl and CF3Br plasmas caused chlorination and bromination of polypropylene surfaces, respectively. Correlations were made between the active species present in the plasmas and the surface chemistry observed on the treated polypropylene substrates.
Preparation Technology for Fine Particle Measurement
Authors: Polke Reinhard , Schäfer Michael , Scholz Norbert
Published: May 2005

Describing the disperse state is important for quality assurance, operational safety and the design and modelling of processes, especially in solids technology. Starting materials, intermediates and end products have to be characterized. Apart from representative sampling, preparation greatly influences the results of particle characterization. Very fine particles are normally agglomerated unless a highly dispersed state is stabilized by an additive. For a meaningful measurement, they must be preserved in this state or be definitely dispersed, depending on the type of problem.

If the point of interest is the present disperse state with regard to the processing characteristics, e.g. for a filtration, the system should not be changed by the preparation method. If it is necessary to determine the property functions, i. e. the functional relationship between technological and physical properties, it is necessary in general to use a high dispersion energy or a long dispersing time in order to obtain the best achievable dispersion. The finer and more unstable a disperse phase is, the more the correct processing is important for the result. The problems of dispersion in gases and liquids are discussed with some examples.
A New Air Classification Principle for the Particle Size range d < 5 μm
Authors: Tilger Jochen , Heidenreich Eberhard
Published: May 2005

Requirements for processes for air classification for the particle size range d < 5 μm are described. A classification principle and first experimental results are presented.
Detection and Chemical Characterization of Polycyclic Aromatic Hydrocarbon aerosols by means of laser‐induced fluorescence
Authors: Niessner Reinhard , Krupp Andreas
Published: May 2005

Laser‐induced and time‐resolved aerosol fluorescence is introduced as an analytical technique for the qualitative and quantitative determination of surface‐bound polycyclic aromatic hydrocarbons (PAHs). The analytical figures of merit are evaluated by studying the fluorescent properties (emission wavelengths and temporal behavior) of PAHs adsorbed on submicrometer NaCl particles. In addition to singly adsorbed PAHs on NaCl particles, a three‐component PAH adsorbate system is characterized. Detection limits are in the range 5 ng/m3 (e. g. for anthanthrene).
Using Sierpinski Fractals to Characterize Changes in the Cytomorphology of hepatopancreatic b‐cells of porcellio scaber latreille (fam: Porcellionidae, crustacea) reared on different diets
Authors: Alikhan M. A.
Published: May 2005

Sierpinski fractal dimension analysis is used to describe the cytomorphology of hepatopancreatic large B‐cell of a terrestrial isopod, Porcellio scaber Latreille (Fam.: Porcellionidae, Crustacea). Isopods were starved for six weeks, and then re‐fed for two days on diets containing glucose and butter. The cytomorphological changes undergone by hepatopancreatic B‐cells after starvation and re‐feeding periods are characterized by their fractal dimensions. The significance of these findings is discussed.
Sieving Capture of Liquidborne Particles by microporous membrane filtration media
Authors: Grant Donald C. , Liu Benjamin Y. H.
Published: May 2005

Test methodology has been developed to measure the particle removal efficiency of microporous membrane filtration media under conditions in which sieving is the dominant particle capture mechanism. The methodology was used to determine the particle capture efficiency of a 0.45 μm membrane filter for removal of submicrometer sized particles from DI water. Particle capture was found to be a strong function of particle diameter, filter media thickness, and filter loading. Particle removal efficiency increased with increasing particle diameter and media thickness. It decreased with increased filter loading when the filters were challenged with the smaller particles used in this study. Removal efficiency initially decreased then subsequently increased during loading with larger particles. Capture was independent of filtration velocity and particle concentration. A sieving model was developed to predict particle capture by the filter media as a function of particle diameter, filter thickness and filter loading. The model was found to accurately predict breakthrough of monodisperse particle suspensions through the media. Particle breakthrough occurred more slowly than predicted when the filters were challenged with a polydisperse particle suspension.
The Work of the British Standards Institution in Particle, surface and pore size characterisation
Authors: Lines Roy W.
Published: May 2005

British Standards committee GME/29/4 is concerned with “Particle sizing methods other than sieving”. Its work covers not only particle size distribution analysis but also methods of estimation of surface area and pore size distribution, as well as a glossary of terms relevant to those subjects. The current British Standards in the BS 3406 series (particle size analysis) and BS 4359 series (surface area) are reviewed, and a progress report is given on the status of several new and revised Standards which are in preparation.
Characterization of BCG Vaccine by coulter counter and scanning electron microscopic techniques
Authors: Groves Michael J. , Klegerman Melvin E. , Devadoss Priscilla O. , Singh Onkar N. , Zong Yueying
Published: May 2005

BCG vaccine, an important immune stimulant used in cancer therapy, consists of a suspension of living and dead cells, cellular fragments and aggregated cells. For this reason, nephelometric methods are unable to determine the total numbers of cells in a vaccine system. Scanning electron microscopy has enabled average cell dimensions to be obtained of length 2.36 μm, width 0.47 μm (n = 1,227), equivalent to a spherical particle of volume 0.3887 μm3 and diameter 0.9055 μm. Measurement of the particle size of a diluted vaccine with a Coulter Multisizer, fitted with a 50 μm diameter orifice, enabled the total number and average size of aggregated cells to be determined. Multiplying the total number by the number of cells in an average aggregate (obtained by dividing the volume of the average aggregate by the average cellular volume) provided a direct estimate of the total number of cells in the system. The total wet weight of cells present in a vaccine ampoule can be estimated by measuring the methylated esters of palmitic acid (PAME) in the system using gas chromatography. This weight, divided by the weight of an average cell, provided an independent confirmation of the total number of organisms present. In order to obtain the cellular density a Percoll gradient sedimentation was carried out. Surprisingly the organisms separated into two fractions of closely similar density, an average value of 1.070 g/mL being obtained. The two fractions had different average sizes with different distribution functions.

When data for a number of lots of TiceTM substrain prepared over a twenty‐two year period were compared, the correlation between the Coulter and PAME methods was seen to be relatively good, bearing in mind the intrinsic variability of biological systems. Comparison with viability (colony‐forming unit) measurements demonstrated a loss in viability with time after preparation.
Measurement of Asbestos Fiber Concentration above Floor Tile
Authors: Lundgren Dale A. , Vanderpool Robert W. , Liu Benjamin Y. H.
Published: May 2005

Abstract temporarily removed. Please refer to PDF file.
Mean Particle Diameters. Part II: Standardization of nomenclature
Authors: Alderliesten Maarten
Published: May 2005

In the science of particulate systems, existing nomenclature systems are not always consistent with each other. The same is true for their physical relevance. A coherent nomenclature system for denoting mean particle diameters is recommended and its physical relevance demonstrated. Comments have been made on a nomenclature for particle‐size distributions to support the proposed nomenclature for mean particle diameters. This nomenclature system does not contain any ambiguities and clearly conveys the physical meanings of mean particle diameters.
Measurement of the Refractive Index of Atomised Liquid Drops by light scattering
Authors: Card Jacqueline B. A. , Jones Alan R.
Published: May 2005

It is demonstrated that the complex refractive index of liquid drops in a spray can be measured using the LDA visibility technique and averaging over a number of particles. A minimum of five scattering angles was required. One of these, close to the forward direction, monitored the particle size. It was estimated that the real part of the refractive index could be measured to within about ± 0.01 and the imaginary part to within ± 0.0004.
Mass Calibration of the Coulter Counter Model ZM
Authors: Figueiredo M. Margarida , Rasteiro M. Graça , Santos Cristina , Monteiro Cristina
Published: May 2005

The calibration of electrical sensing zone instruments is normally achieved by using spherical particles with a certified size. An alternative and more fundamental procedure, known as mass or self‐calibration, is to use particles of the material under test.

This work concerns the mass calibration technique, in particular the equations used to calculate the mass calibration constant. It is demonstrated that some of the published expressions are inconsistent. An expression particularly suitable for the Coulter Counter Model ZM has been derived and validated. Some experiments were also performed using irregular particles, in order to compare both calibration methods.
An Algorithm for Determination of the Size‐Dependent breakage frequency of droplets, flocs and aggregates
Authors: Chang Yu‐Chen , Calabrese Richard V. , Gentry James W.
Published: May 2005

A method, based on the use of discrete size classes, is developed to extract size dependent breakage frequencies from sequential measurements of the size distribution. In order to obtain good resolution and allow for several breakage modes, interlaced Fibonacci series are used to define the size classes. Both binary and ternary breakage are considered. An approach based on Kernel Discriminant Analysis is used to focus the breakage at the discrete size classes. The algorithm is tested using simulated distribution data. The sensitivity of the retrieved breakage frequencies to the assumed progeny distribution and to the number of breakage events between samples is considered. The numerical experiments show that the method is effective even when the breakage mechanism is not well understood.
Calculation of the Shock Temperature of Porous and non‐porous high explosives
Authors: Kolkert W. J.
Published: May 2005

The increase in temperature by shock‐compression of non‐porous high explosives was calculated by the Walsh‐Christian technique. Extension of this model to porous media enabled us to calculate the increase in temperature of shock compressed porous high explosives at different loading densities. As an example, calculations have been performed for Composition B at different loading densities. The results are discussed.
Statistical Aspects of Sensitivity Testing in the international transport regulations RID/ADR
Authors: Janswoude J. J.
Published: May 2005

For two frequently applied methods of determining the characteristic values of statistical quantities in the RID/ADR (concerning the pressure vessel test, the Koenen test, the friction test and the fallhammer test) the reliability has been calculated. It appears that the results are strongly dependent on the number of experiments and on the relative level distance prescribed in the instructions. Further the starting level may have great influence. The reliability of practical determination varies from about 0.5% up to about 80%. However, reproducibility is quite insufficient in nearly all cases.
Safety and Technological Aspects of Black Powder
Authors: Hahn H. , Hintze W. , Treumann H.
Published: May 2005

For 13 different types of black powder, the safety parameters and the corresponding danger values were determined according to the methods of BAM. The investigations have shown that three‐component powders containing 75% potassium nitrate have a somewhat higher danger level than the corresponding powders containing 70% potassium nitrate only. However, in both cases, the thermal sensitivity is almost the same.

The heats of explosion and the maximum gas pressures measured in the ballistic bomb increase with rising potassium nitrate content within the tested range of concentration.

Despite their equal chemical composition, the various powders differ partly to a considerable extent as regards the rate of pressure buildup measured in the ballistic bomb. The latter will rise with both an increase of the content in potassium nitrate and decreasing grain size and density. The whirling height determined in the eprouvette and the burning velocity at atmospheric pressure in the open channel will be reduced with increasing grain size.

In case the powder grain are ground down or compressed, the explosive properties will be reduced, too.
Effect of Variables on Ignition Delays of hydrazone/nitric acid systems
Authors: Jain S. R. , Krishna P. M. M. , Verneker V. R. Pai
Published: May 2005

The effect of relative amounts of fuel and oxidizer, composition of the oxidizer and compactness of the fuel on ignition delays of hydrazones with nitric acid has been studied. Several of the hydrazones give minimum ignition delays at the mixture ratio close to the stoichiometric ratio. Ignition delays of phenyl‐ and dimethylhydrazones are greatly influenced by the acid composition. Longer ignition delays are observed with the acids having higher concentrations of NO2. A reaction mechanism leading to hypergolic ignition has been proposed for phenylhydrazones/nitric acid systems. Longer ignition delays are observed when the fuels are taken in compacted forms.
Length and port size effects on Combustion of PVC Plastisol Hybrid Fuel
Authors: Chatterjee A. K. , Joshi P. C.
Published: May 2005

The combustion behaviour of a cylindrical port burning PVC plastisol hybrid fuel grain in an oxidizing stream of gaseous oxygen has been studied and the effects of grain length and port size on the local regression rate, average regression rate and mass consumption rate have been investigated. Various combinations of grain length and port size have been employed to give a wide range of L/D ratios from 8 to 100. The average regression rate is found to increase with the increase of L/D ratio, whereas the mass consumption rate is found to decrease with the increase of L/D ratio. An attempt has also been made to correlate the fuel mass consumption rate with the Reynolds' number and the total mass flux.
The Preparation of Hexanitrostilbene from Hexanitrobibenzyl
Authors: Gilbert E. E.
Published: May 2005

The title reaction was effected by oxidation with copper(II) compounds, halogenating agents, quinones, and air or oxygen, in the last case preferably with the addition of a promoter. These procedures are all conducted in basic medium, and require a correct choice of reaction solvent.
Burning Rate Evaluation of Composite Solid Propellants. A simplified approach
Authors: Swaminathan V. , Soosaimarian M.
Published: May 2005

One of the principal parameters associated with a solid propellant is its linear burning rate. Many attempts have been made in the past to determine theoretically the burning rates of solid propellants by the use of appropriate combustion models. The object of the present paper is to propose a simplified theory of burning rate suitable for composite solid propellants. While the paper follows basically the scheme suggested for this purpose by Beckstead, Derr and Price using multiple flamelets, certain simplifying assumptions have been introduced with a view to make the model easier to operate. An attempt is also made in the paper to extend it to the case of aluminized solid propellants as well on the basis of a specific hypothesis regarding the role of aluminium. The relevant transcendental equations of combustion were solved on a digital computer. The burning rates and related characteristics were evaluated by this technique for two specific ammonium perchlorate‐based solid propellants, one aluminized and the other non‐aluminized, and the results obtained agree reasonably with the reported experimental trends.
A numerical study of the Behaviour of Liquid and Slurry Explosives under projectile impact
Authors: Feng K. K. , Hanasaki K.
Published: May 2005

The basic processes in the projectile impact of slurry explosives containing gas bubbles are investigated numerically using a two‐dimensional unsteady state model. The partial differential equations derived from the laws of conservation of mass and momentum, together with the equation of state proposed by Tait are solved by means of a finite difference TENSOR computer code. The model describes the continuous time dependence of the pressure, velocity and displacement in the slurry explosive under dynamic loading.
The Natural Spread and Tumbling of the Shaped Charge Jet Segments
Authors: Hirsch E.
Published: May 2005

The collapse mechanism of the shaped charge jet prevents the formation of a jet, the segments of which move in a straight line with absolute accuracy, even under the assumption that the shaped charge is ideally symmetrical. This is a result of the fact that the jet break‐up mechanism already starts at the collapse stage, in which the liner material has a big transversal velocity component.

A model for calculating the distribution of the angle by which the jet segments' direction of movement deviates from the shaped charge axis of symmetry (the spread angle) is presented in detail. The tumbling frequency of the segments as a function of their velocity and final length is also predicted by the theory.

The predictions made by applying the model to the standard 83.8 mm 42 degrees opening angle B.R.L. precision shaped charge were found to be consistent with the data published in open literature. The comparison of these predictions with the data leads also to the conclusion that the cutoff in the copper jet penetration into steel targets occurs when the jet segments start to hit the walls of the already formed hole instead of reaching its bottom without being disturbed on their way.
Thermal Explosion of Explosives and Propellants. A review
Authors: Merzhanov A. G. , Abramov V. G.
Published: May 2005

The principal results of thermal explosion theory are reported and some specific features of condensed‐phase explosion are discussed. Methods of experimental studies and some experimental results are given.
Smoke generators. I. The Ignition of Pyrotechnic White Smoke compositions containing hexachloroethane and silumin by means of an electrically heated coil
Authors: Hartley F. R. , Murray S. G. , Williams M. R. , Jones D. B.
Published: May 2005

The ignition by electrically heated coil of two smoke generators containing hexachloroethane and silumin, one of which also contains zinc oxide, has been investigated. The physical conditions of consolidation, that is pressing load (between 7.9 × 106 kg/m2 and 3.1 × 107 kg/m2) and diameter of container (between 1.27 cm and 2.54 cm), have been shown to have no effect on the ease of ignition of each mixture. Addition of zinc oxide increases the minimum temperature of ignition from about 443 K to about 973 K and the minimum heating rate for ignition from about 2.5 watt to about 8 watt. The effect of zinc oxide is believed to be chemical rather than physical in nature.
Shock‐Wave measurements in water for calibrating the BICT‐Gap Test
Authors: Trimborn F. , Wild R.
Published: May 2005

By means of shock‐wave measurements it was possible to calibrate the BICT‐gap test. The relation between the height of the gap and the shock‐wave peak pressure at the end of the gap is described. From other considerations the range where the test can be used, can be obtained. BICT‐gap test will be used to test explosives whose critical diameters do not exceed 20 mm and which will be initiated by shockwave pressures from 7 kbar to 60 kbar. The test method can be regarded as a small scale‐gap test for military explosives.
A Penalty Function Approach to the Optimization of Chemical Propellant Systems using the fletcher‐powell algorithm
Authors: Swaminathan V. , Madhavan N. S. , Chacko C. M.
Published: May 2005

This article presents an efficient numerical algorithm for determining, for a given metallized propellant system, the optimum combination of reactants which can fetch the maximum specific impulse, and also the salient features of the associated computer program. The optimization procedure is based on the Fletcher‐Powell technique with the objective function being augmented by a penalty term to accommodate the constraints. Numerical results for the optimization, obtained by means of a computer program written in FORTRAN IV on the IBM‐360 computer for a representative propellant system, are also presented in this note.
Parameter optimization of the Explosive Compaction of Porous Materials
Authors: Roman O. V. , Pickus I. M.
Published: May 2005

The paper considers the problems of numerical discovering the shock wave parameters in porous materials. The taks is solved in continuum approximation by replacing the original heterogeneous system with a model, the properties thereof are described in similarity criteria, determining the body compressibility, the shock wave velocity scale and “strength” of the disturbing acting on the substance. Given are the basic equations to calculate π(x)‐dependences. The comparison with results of the calculation and with experimental data testifies in favour of the given ideas.

The composition of three‐dimensional (P, θ, θ0) state surfaces illustrates the active affect of porosity on dynamic compression of the dispersed materials. The analysis of typical surface state bendings permits to choose correctly the optimal means and methods of impulse loading for obtaining the needed technological effects.
The Initiation of Covered Composition B by a Metal Jet
Authors: Chick M. C. , Hatt D. J.
Published: May 2005

The initiation and build‐up to detonation of Composition B covered by steel barrier plates and impacted by a shaped‐charge jet has been studied. Two different barrier thicknesses were used representing strong and weak shock initiating systems. The results showed that, in both cases, a shock (designated the precursor shock) that travelled ahead of the penetrating jet and entered the explosive was roduced when the jet impacted the steel surface. The strong precursor shock from the thin barrier system produced initiation close to the explosive surface while for the weak precursor shock from the thick barrier system there was a long run to detonation (40 mm, 11 μs). In the latter case, close to the onset of detonation, a retonation was observed moving back through the previously shocked explosive which was expanding radially. These observations are used to discuss and explain some of the apparent anomalies in previously reported work. The effect of the precursor shock on the classical jet penetration theory was estimated.
TNT — Equivalent
Authors: Held M.
Published: May 2005

For engineering purposes, the effects of blast waves on various target structures can be estimated quite easily with the aid of TNT‐equivalence. On the one hand, many experimental data are available on the blast damage done to structures, and on the other hand, the energy content of any source can be expressed in terms of an equivalent mass of TNT. The parameters involved in the propagation of a blast wave and in its interaction with target structures are discussed at some length in order to point out the inherent inaccuracies as well as the limits of applicability of the TNT‐equivalence method.
Volumes and Sound Speeds of Two Gun Propellants at high pressure
Authors: Costantino M.
Published: May 2005

Gun propellants are subjected to a variety of high stress states during the ballistic cycle. Attempts by constitutive modelers to describe the response of the propellant during the cycle are hampered by an almost complete lack of well‐characterized experimental data at high pressures. We present quasistatic, hydrostatic pressure‐volume, and compression and shear‐wave‐speed data on two formulations of a low porosity propellant. The hydrostat shows three distinct regions at pressures to 200 MPa. Below about 60 MPa, the response is elastic, with an effective compressibility controlled by the porosity; from ∼60 Mpa to 140 MPa the porous matrix fails and the material softens as the porosity distribution is crushed; above ∼140 MPa, the bulk modulus continues to increase to the value for the matrix. Both the hydrostat and sound speed data show significant time‐dependent effects with characteristic times of ∼103 s and > 104 s.
A New Approach to Crack Growth in rubbery composite propellants
Authors: Kinloch A. J. , Tod D. A.
Published: May 2005

Upon being stressed, modern rubbery composite propellants typically exhibit pronounced bulk inelastic behaviour, ie hysteresis occurs. Hence, fracture mechanics parameters ascertained assuming linear‐elastic fracture mechanics (LEFM) are invalid. The present paper develops quantitative analysis which allow for bulk inelastic effects and therefore enables values of the fracture energy, Gc, to be determined which are truly material parameters, independent of test geometry and loading conditions. Only methods which take into account the bulk inelasticity of such propellants will result in accurate and useful values of Gc which will enable sound design and life prediction analyses to be undertaken.
Quasi‐Static compaction studies for DDT investigations. Ball Propellants
Authors: Elban W. L.
Published: May 2005

A Quasi‐Static compaction study has been performed on a number of ball propellants to complement studies of dynamic compaction behaviour, shock sensitivity, and deflagration‐to‐detonation transition (DDT) behaviour that are currently being conducted for high porosity granular beds of such materials. These ball propellants are of interest because they are simple, unfilled propellant systems. Many of them have particles which are spherically shaped, a geometry that facilitates numerical modeling of the DDT process. Four Olin ball propellants, designated as WC 140, TS 3660, Type A Fluid, and Winchester #231, have been investigated in detail by simultaneously measuring applied force, transmitted force, and porous bed displacement. An average axial compressive force per unit radial cross‐sectional area of the solids in the porous bed, called the „intragranular stress”︁, is then calculated as a function of percent theoretical maximum density for values ranging initially from 44%–58%, to final values greater than 85%, depending on the ball propellant. A microscopic examination was performed on a number of recovered samples that had been compacted to various stress levels to identify the nature and extent of plastic deformation and fracture in the propellant particles and to provide insight into compaction mechanisms and associated pore structures in the compacted porous bed. A brief discussion relating these considerations to hot spot formation and DDT behaviour is also presented.
Investigation of the Decomposition Processes in Single‐Base Propellants under vacuum using a minicomputer‐controlled automated apparatus
Authors: Kučera V. , Vetlický B.
Published: May 2005

There is described the application of an automated vacuum stability test in following the decomposition and the stability of single base propellants. The relations of the propellant decomposition rate, evaluated from the loss of stabilizer, to the decomposition rate measured at the stability test were verified. The data obtained indicate the applicability of the vacuum test to check the chemical stability of propellants.
An Interphasic Region between Nitrocellulose and Nitroguanidine in triple base propellant
Authors: Fong C. W. , Warren R. C.
Published: May 2005

Evidence for the existence of an interphasic region in the nitroglycerin‐nitrocellulose matrix immediately surrounding the crystalline nitroguanidine filler in triple base propellant is presented for the first time. This interphasic region displays anomalous thermal expansion and mechanical relaxation behaviour compared to the bulk nitroglycerin‐nitrocellulose matrix in the propellant. The interphasic region accounts for the highly unusual thermal expansion behaviour of triple base propellants containing long needlelike nitroguanidine crystals. An interphasic region does not occur in similar propellant when the nitroguanidine filler is replaced by crystalline RDX. Thus the interphase region is thought to be a manifestation of a significant bindernitroguanidine interaction. Implications for munition survivability stemming from the existence of a separate polymeric interphase are discussed in terms of the thermal and relaxation behaviour of the interphasic binder‐crystalline filler interface.
The Role of Alumina Trihydrate Filler on semiflexible unsaturated polyester resin‐4 and inhibition of double‐base rocket propellants
Authors: Agrawal J. P. , Chowk M. P. , Satpute R. S. , Kulkarni K. S.
Published: May 2005

The use of unsaturated polyesters for inhibition of double‐base rocket propellants has become popular in recent years. A direct bonding inhibition system termed as semiflexible unsaturated polyester resin‐4 has been recently developed and reported by us. It has been reported in literature that the use of some fillers such as antimony trioxide, titanium dioxide, lithophone, alumina trihydrate etc. impart better mechanical and heat resistance properties. The effect of 10% to 60% of alumina trihydrate (Al2O3 · 3 H2O) on semiflexible unsaturated polyester resin‐4 in respect of gel time, exotherm peak temperature, tensile strength, %‐elongation, nitroglycerin absorption, water absorption, heat resistance and flame retardance has been studied and the result obtained have been discussed. It is observed that 30% of alumina trihydrate imparts desirable properties. The 108 mm and 148 mm‐diameter propellant sustainers inhibited with resin‐4 containing 30% alumina trihydrate and conditioned at ambient, sub‐zero temperature (−40°C for 18 hr) and high temperature (+50°C for 18 hr) were statically evaluated. The pressure‐time profiles at all temperatures have been found to be flat and neutral which infer that the inhibition system works satisfactorily.
Thermoanalytical Investigation of Stored Ammonium Nitrate doped with diammine copper‐(II)
Authors: Engel W.
Published: May 2005

Ammonium nitrate doped with diammine copper dinitrate and stored for 10 years was reinvestigated by DTA and TMA. The phase transition IV/II and IV/III, which are of interest for the practical use, still occur above 50°C. In spite of moisture contents between 0.4% and 1.4% no caking was observed.
Determination of the Material Quality of Copper Shaped Charge Liners
Authors: Held M.
Published: May 2005

When several liners as well as high explosive charges are produced in identical and reproducible ways resulting in identical or at least similar sizes and geometries, differences in the total lengths of the shaped charge jets will indicate differences in copper quality.

This paper outlines guidance for taking flash X‐ray pictures of shaped charge jets for this purpose, and for an analysis of the pictures at least for a comparative assessment. The penetrating capability can be derived from the particulation times.
Combustion of HMX‐CMDB Propellants (II)
Authors: Yano Y. , Kubota N.
Published: May 2005

The burning rate characteristics of HMX‐CMDB propellants were examined as a function of HMX concentration. In the region of low HMX concentration, below about 50%, the burning rate decreases with increasing the HMX concentration. However, in the region of high HMX concentration, above about 50%, the burning rate increases with increasing the HMX concentration. When the measured results are extrapolated to the 100% HMX concentration, it is recognized that the burning rate approaches the burning rate of an HMX single crystal. The burning rate analysis indicates that the effect of the addition of HMX particles within double‐base propellants on burning rate is determined by the reaction rates in the gas phase and in the condensed phase. The gas phase reaction rate in the fizz zone decreases monotonously as the HMX concentration increases. On the other hand, the heat of reaction at the burning surface increases as the HMX concentration increases. The experimental results indicate that the burning rate with low HMX concentration is mainly controlled by the gas phase reaction rate and the burning rate with high HMX concentration is mainly controlled by the condensed phase reaction rate.
Study of an Explosive‐Driven Metal Plate
Authors: Yadav H. S. , Kamat P. V. , Sundaram S. G.
Published: May 2005

Equation of motion of an incompressible metal plate, accelerated by a plane detonation wave, has been solved for a general value of adiabatic exponent ß of detonation products to investigate its effect on terminal velocity of the plate. It has been found that the plate velocity increases with decreasing value of ß. The magnitude of this effect has been found sufficient to determine adiabatic exponent of detonation products from the measurement of flyer plate velocities at different C/M ratios.

Velocities of metal plates, hurled by contact explosion of high density explosives, have also been measured with oscillographic technique by using an experimental setup which is insensitive to air shocks. The plate velocities measured by such an experimental setup have been found in good agreement with theoretical ones.
The Orthogonal Synchro‐Streak Technique as a Diagnostic Tool, particularly for shaped charge jets
Authors: Held M.
Published: May 2005

The test set‐up for recording a shaped charge jet by the orthogonal synchro‐streak technique (OSST) is described. By means of an example it is shown how the information on the deviation of the jet elements in X, Y‐ and in polar co‐ordinates as well as that on the length of the jet and on the times of particulation can be extracted from the streak record.
The Influence of the Variation of Combustion Chamber Volume under pressure load on the determinational of thermodynamic characteristics of solid propellants in pressure bombs
Authors: Grune D.
Published: May 2005

Detailed combustion studies in high‐pressure bombs show that the measured maximum gas pressures are always lower than theoretically calculated values and that these differences increase more than proportionally with rising loading densities. By means of experiments and calculations we show that a considerable part of the pressure difference is brought about by the expansion of the combustion chamber during pressure load.

The expansion of the combustion chamber is responsible for pressure measurements that are about 5% too low at currently used pressures of 500 MPa. Furthermore the covolume yields an error of about 12% if the constants of the Abel state equation are determined using the standardized method for loading densities of 0.20 g/cm3 and 0.22 g/cm3. The error of the force constant remains under 1%.

As the values determined from pressure bomb measurements are to be introduced into further calculations, they must be corrected according to the combustion chamber expansion, or new measuring methods will be necessary.
A Correction for Ejection Angles of Fragments from Cylindrical Wareheads
Authors: König P. J.
Published: May 2005

The problem of end effects influencing the ejection angles of fragments near the ends of cylindrical warheads is approached semi‐empirically. A correction term is added to the Taylor angle, based on the accepted concept that the reduced fragment velocities near the ends of a warhead are due to release waves in the detonation gas. Acceptable agreement between experiment and prediction is found for available experimental data. The results indicate that the accelerative drag due to the axially‐outward component of the release‐wave gas flow over the fragments dominates the divergence of the fragments for prefragmented casings, the axial pressure drop playing a minor part, while the reverse seems to be true for the divergence of fragments from solid casings.
Combustion Mechanism of Double‐Base Propellants with lead burning rate catalysts
Authors: Youfang Cai
Published: May 2005

On the basis of relevant experimental phenomena and results, which also include the results on the domain of non‐propellant combustion, this paper has determined basic reactions caused by lead burning rate catalysts in the combustion process and their approximate reaction temperature. In the presence of carbonaceous matter on the burning surface the partial NO is reduced to N2 through six reactions occurred on the carbonaceous matter instead of the reaction between NO and CO. As a result of changing the reducing path of a part of NO the burning rate rises through increasing the temperature gradient in the fizz zone at the burning surface. The reactions between PbO and C and between PbO and CO check the burning rate to rise through expending carbonaceous matter on the burning surface and causing char particles to “fly off” the burning surface. The super‐rate, plateau and mesa effects are perfectly explained with these reactions and the fundamentals of heat transference. The production of the effects arises from the competing of two actions to increase burning rate and to check the burning rate enhancement of lead burning rate catalysts and the effect of the pressure on the burning rate. Because of the fact that the chance to form carbon nuclei and the time of the carbon deposit, the covering ratio of the carbonaceous matter on PbO particles, and the temperature increasing rate and the lagging temperature difference in C‐PbO interfaces depend on the pressure, the ability by the reaction between PbO and C and between PbO and CO checking the burning rate to rise makes a great difference in different ranges of the pressure. In addition, according to the combustion mechanism advanced in the paper the effects of the physical and chemical properties of lead burning rate catalysts, especially their ability to absorb the ultraviolet light, on the rate‐increased values and the pressure ranges of the plateau and the mesa regions have been expounded.
The design and instrumentation of a simple system for demonstrating underwater explosive effects
Authors: Barnes R. A. , Hetherington J. G. , Smith P. D.
Published: May 2005

The design and testing of a system for studying underwater explosions is described together with the design of a suitable charge for use in the facility. From the results obtained it is concluded that the system offers a relatively simple method of demonstrating underwater explosion phenomena.
Calculations of Derivative of Second Virial Coefficients based on the exp‐6 intermolecular potential
Authors: Xiong Wu , Jian Sun
Published: May 2005

The quantity of the partial derivative of second virial coefficients with respect to temperature in reduced form, T*∂B*/∂T* has been computed for an exp‐6 intermolecular potential

The results are tabulated over the reduced temperature range T* from 0.4 to 400, and for seven values of the parameters α from 12 to 15. The outputs lead us to lay the foundation for the applications of the theoretical virial type equation of state (6) like VLW using the best form exp‐6 for high pressure studies.
Continuous automated production facility for the manufacture of single‐base propellant powders
Authors: v. Helle C. J.
Published: May 2005

The design‐features of the first continuous single‐base propellant powder plant in the Western Hemisphere are summarized in this report. The highlights: less investment is required to install this simplified manufacturing process. Unmanned automated operations assure improved product quality, lower operating cost, and better safety conditions. As a result of an advanced design the plant is simple, easy to operate, very versatile, and flexible to accommodate changes.
Modification of the Physical Properties of an Extruded Double‐Base Propellant following solvent vapour exposure
Authors: Barter I. , Newell A. , Privett G.
Published: May 2005

Samples of a rolled double‐base propellant were exposed to acetone vapour and the rate of solvent uptake observed. The solvent was subsequently removed and dynamic mechanical and extensometer measurements were made on the dried samples.

The percentage elongation at break and the ultimate tensile strengths of the samples after solvent treatment were considerably above that of the control samples. The solvent uptake modified the relaxation behaviour of the samples and consequently the values of Young's modulus within the temperature range 30°C to 60°C. The solvent uptake was found to be non‐Fickian.

Samples that had been thermally annealed prior to solvent vapour treatment were also examined. In general the behaviour was similar to that of unannealed samples but the scale of some of the changes and the rate of solvent uptake was modified.
Thermal Decomposition of energetic materials. 39. Fast thermolysis patterns of poly(methyl), poly(ethyl), and primary alkylammonium mononitrate salts
Authors: Russell T. P. , Brill T. B.
Published: May 2005

Fast thermolysis (> 100°C/s)/FTIR spectroscopy of alkylammonium mononitrate salts is described in terms of the gas products and the temperature and time correlations of their evolution. The salts studied are [(CH3)nNH4‐n]NO3, n = 1–3; [(CH3CH2)nNH4‐n]NO3, n = 1–4; and [CH3(CH2)nNH3]NO3, n = 0–3. In addition to the patterns among the small molecule thermolysis products, the tendency to form nitrosamines, amides, and alkylnitrates is presented. The release of HNO3 qualitatively correlates with the basicity of the parent amine. The tertiary ammonium nitrate salts did not release HNO3(g). The release of NH3(g) appears only to occur when the residue can stabilize itself. Otherwise, the parent alkylamine is released. The formation of nitrosamines upon fast thermolysis of di‐ and trialkylammonium nitrate salts makes these materials a potential health risk in formulations. There is no evidence that the nitrate salts convert to nitrosamines through a nitramine intermediate.