bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractBCG 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.
Mean Particle Diameters. Part II: Standardization of nomenclature
Authors: Alderliesten Maarten 
Published: May 2005

AbstractIn 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

AbstractIt 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

AbstractThe 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

AbstractA 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

AbstractThe 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

AbstractFor 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

AbstractFor 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

AbstractThe 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

AbstractThe 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

AbstractThe 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

AbstractOne 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

AbstractThe 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

AbstractThe 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.
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

AbstractThe 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

AbstractBy 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

AbstractThis 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

AbstractThe 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

AbstractThe 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

AbstractFor 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

AbstractGun 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

AbstractUpon 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

AbstractA 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

AbstractThere 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

AbstractEvidence 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.