bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diameter Effect and Failure Diameter of a TATB‐Based Explosive
Authors: Campbell A. W. 
Published: December 2004

AbstractThe detonation velocity of PBX‐9502, an explosive consisting of 95 wt% TATB and 5 wt% Kel‐F 800, was measured precisely over a range of charge diameters at 75°C, 24°C, and −55 °C. The diameter‐effect curves obtained by plotting detonation velocity versus the reciprocal of charge radius were found to differ from those reported in the literature for other solid and liquid explosives, being concave upward at large diameters. The curve at 75°C was found to be a straight line at small diameters and thus simulates the behavior of a homogeneous explosive. At intermediate charge diameters, the effect of varying the temperature by 130°C was quite small. The failure diameter varied from 5.85 ± 0.15 mm at 75°C to 10.5 mm at −55 °C.
A Relationship between Impact Sensitivity and Molecular Electronegativity
Authors: Mullay J. 
Published: December 2004

AbstractIt is shown that statistically significant relationships exist between impact sensitivity and molecular electronegativity for several classes of organic high explosives. These include polynitroaromatic and polynitroaliphatic molecules. The correlations closely follow previous results which utilize the idea of “trigger linkages” (C–NO2, N–NO2 or O–NO2) and oxygen balance. However, the present work provides the possibility of establishing a closer relation between impact sensitivity and electronic structure for the molecules studied. It can also be used to clarify the relationship between the results of previous efforts with these molecules and similar work with other explosives. Through a closer analysis of these correlations it is also shown that the presence of a CO2 moiety in the molecules affects the impact sensitivity.
New Developments in the Field of Firing Techniques
Authors: Ziegler K. 
Published: December 2004

AbstractAfter an introducing description about the development of electric firing systems the author tries to answer the question why so many new firing systems were developed within the last years, although the electric firing has reached a high level of elaboration.The following firing systems are described with their advantages and disadvantages: Magnadet system which works on the basis of electric induction, detonators without primary charge as flying plate detonators or exploding bridge wire detonators, and non‐electric firing systems as Nonel‐system and Hercudet‐system.
Calculation of the Wave‐Shaper Effects on Detonation Wave in Shaped Charges
Authors: Pezzica G. , Pazienza G. 
Published: December 2004

AbstractResults are presented from two‐dimensional computations simulating the development of detonation for various configurations of shaped charges containing inert elements. These calculations were performed using the nonlinear explicit finite‐difference computer code PISCES 2D ELK. The numerical model employed represented the high explosives by a finely zoned Lagrangian mesh and used JWL (Jones‐Wilkins‐Lee) equation of state with C‐J (Chapman‐Jouguet) burn model. The inert elements were modeled by Lagrangian grids and used Mie‐Grueneisen equations of state with a linear relationship between the shock velocity (Us) and particle velocity (Up) fitting the Hugoniot data of the inert materials. The development of detonation waves all around the wave‐shaper are shown in contour plots of pressure at various time steps during the calculations. Mesh plots of the different configurations are also reported. Our simulations are compared with previous radiographic and numerical results for a slab of explosive with an aluminium confinement and with recent not yet published streak‐camera tests on a particular shaped charge configuration with hemispherical wave‐shaper. Our numerical results appear to be in good agreement with the experimental data.
Combustion Mechanism of Azide Polymer
Authors: Kubota N. , Sonobe T. 
Published: December 2004

AbstractThe combustion wave structure and thermal decomposition process of azide polymer were studied to determine the parameters which control the burning rate. The azide polymer studied was glycidyl azide polymer (GAP) which contains energetic – N3 groups. GAP was cured with hexamethylene diisocyanate (HMDI) and crosslinked with trimethylolpropane (TMP) to formulate GAP propellant. From the experiments, it was found that the burning rate of GAP propellant is significantly high even though the adiabatic flame temperature of GAP propellant is lower than that of conventional solid propellants. The energy released at the burning surface of GAP propellant is caused by the scission of NN2 bond which produces gaseous N2. The heat flux transferred back from the gas phase to the burning surface is very small compared with the heat generated at the burning surface. The activation energy of the decomposition of the burning surface of GAP propellant, Es, is determined to be 87 kJ/mol. The burning rate is represented by r = 9.16 × 103 exp(–Es/RTs) where r (m/s) is burning rate, Ts (K) is the burning surface temperature, and R is the universal gas constant. The observed high temperature sensitivity of burning rate is correlated to the relationship of (∂Ts/∂T0)p = 0.481 at 5 MPa, where T0 is the initial propellant temperature.
Evaluation of a new organic azide: Hexakis(azidomethyl)benzene (HAB)
Authors: Gilbert E. E. , Voreck W. E. 
Published: December 2004

AbstractHAB is a thermally‐ and hydrolytically‐stable solid, easily prepared from available raw materials. It is not highly sensitive to shock, friction, or electrostatic charge, but is sensitive to some types of impact, although not to others. It shows preliminary promise for possible use as a substitute for normal lead styphnate in less‐sensitive bridgewire detonators, and as a substitute for tetracene in percussion detonators, e.g. the M‐42 primer. Easy ignition, and a high burning rate without detonation, suggest application as an igniter. HAB is not sufficiently powerful to dent an aluminum witness block; therefore, it would not be suitable as a replacement for lead azide as an intermediate detonator charge.
Role of Boron in Burning Rate Augmentation of AP composite propellants
Authors: Kuwahara T. , Kubota N. 
Published: December 2004

AbstractEffect of the addition of boron particles on the burning rate of solid propellants was examined. The propellants tested in this study consisted of ammonium perchlorate (AP) as an oxidizer and carboxyl terminated polybutadiene as a fuel binder. The propellant burning rate is increased significantly by the addition of a small amount of boron particles. The burning rate augmentation is dependent largely on the size and concentration of the boron particles mixed. Thermochemical experiments revealed that the boron particles react with the decomposed gases of AP on and just above the propellant burning surface. The heat flux transferred back from the gas phase to the burning surface of the propellant increases with increasing the total surface of the boron particles mixed within the unit mass of propellant. The burning rate augmentation is correlated to the heat of reaction generated by the oxidation reaction of boron particles.
On the Hydrodynamic Theory of Detonation
Authors: Schall R. 
Published: December 2004

AbstractWhen the enthalpy of the unreacted explosive is correctly taken into account, the detonation rate D depends to some extent on the explosive's sound speed a0. With a perfect or Abel gas equation, correction terms of the order \documentclass{article}\pagestyle{empty}\begin{document}$ 1 - \frac{{{\rm a}_{\rm 0}^{\rm 2} }}{{{\rm D}^{\rm 2} }} $\end{document} with respect to the classical theory are obtained. They increase D, but lower density and pressure in thc C‐J plane. This agrees with the finding that data derived from experiments on the basis of the classical theory correspond better to a weak Than to a C‐J detonation. The observed difference in density coefficients, dD/dϱ0, of liquid and solid TNT as well as the anisotropy of D of elastically stretched rubberized high explosives are quantitatively understood. It is shown that the extended equations, though based on a gas equation of state, hold approximately for condensed explosives too, provided their compressibility is not too low.
The Initiation Threshold Sensitivity of LX‐15 Explosive as a function of its grain size
Authors: Gvishi M. , Solomonovici A. 
Published: December 2004

AbstractThe effect of the explosive binder 5 w/o‐Kel‐F‐800 on the initiation threshold sensitivity of LX‐15 had been measured. The initiation threshold (kinetic energy of flyer plate) versus explosive grain size shows constant difference of 5.5 ± 0.5 J/cm2 between threshold curves of HNS and LX‐15 explosives (HNS plus 5 w/o‐Kel‐F‐800). This result can be explained by hot spots model.
The cylinder test in the context of physical detonation measurement methods
Authors: Hornberg H. , Volk F. 
Published: December 2004

AbstractA survey is given of the problems encountered in measuring where detonation physics are involved and the measurement procedures applied in their solution. The cylinder test is assigned a part within this framework and compared with competing measurement procedures. This test makes it possible to calculate the progression of detonation product expansion from the widening of the tube measured which, in turn; is needed as an input for computer programs to examine material deformation caused by explosives. The LLNL and ICf evaluation programs are presently available for this purpose. In addition, Gurney energies can also be determined as characteristic magnitudes for explosive effects either directly from the tube expansion or indirectly from the product expansion. Apart from density of explosive and velocity of detonation, both the Chapman‐Jouguet pressure as well as the detonation heat are required in order to establish the initial point of the product expansion curve. In the ICT program, both quantities can also be obtained through detailed examination of the flow conditions in tubes of variable cross‐sections, in conjunction with limit observations on the wall expansion progression; this makes the cylinder test independent of other measurement procedures.
Energetics of BAMO
Authors: Miyazaki Toshio , Kubota Naminosuke 
Published: December 2004

Abstract3,3‐Bis(azidomethyl)oxetane (BAMO) is a typical energetic azide polymer containing two N3, bonds in the molecular structure. Since BAMO is a solidified polymer at room temperature, a liquid BAMO copolymer with tetrahydrofuran (THF) was synthesized in order to gain energetic binders for solid propellants. Various types of experiments were carried out to elucidate the decomposition and combustion processes of BAMO polymer, BAMO/THF copolymer, and crosslinked BAMO/THF copolymer. The heat produced by the decomposition is caused by the bond breakage of ‐N3 to produce N2, gas. The burning rate characteristics of crosslinked BAMO/THF copolymer depend largely on the mole fraction ratio of BAMO and THF.
Thermal Stability of ε‐Hexanitrohexaazaisowurtzitane in an Estane Formulation
Authors: Foltz M. Frances 
Published: December 2004

AbstractA change in color and density during prolonged heating of a formulation containing ε‐hexanitrohexaazaisowurtzitane (HNIW) and Estane 5702 was investigated by Fourier transform infrared (FTIR) spectroscopic analysis. Starting materials, virgin and final colored formulation were studied. Analysis revealed polymorphic impurity at all stages of production and processing, the nature and concentration of which changed with treatment of the material. Thermally‐induced polymorphic conversion was determined to be the cause of the decrease in density, whereas the color change was speculated to be the result of binder degradation. Sensitivity to impact, friction and electrostatic spark were unchanged.
Review on Benzofuroxan System Compounds
Authors: Naixing Wang , Boren Chen , Yuxiang Ou 
Published: December 2004

AbstractThis paper reviews on benzofuroxan system compounds about structure, preparation and development. The replacement of nitro groups by furoxano groups on aromatic ring can increase density, detonation velocity and energy of explosives, so benzofuroxan system compounds and some energetic materials have aroused much attention.
Flame Spreading in a LOVA Charge: An Experimental Study
Authors: Wildegger‐Gaissmaier A. E. , Johnston I. R. , Teague G. 
Published: December 2004

AbstractLOVA propellants due to their low sensitivity are difficult to ignite. ‘Non‐ideal’ ignition can result in loss of accuracy, misfire, hangfire or catastrophic failure of the gun. The flame spreading event can be used to evaluate the ignition process. An experimental technique has been developed to aid in the investigation of flame spreading in gun charges. Fibre optic sensors as a direct measurement method were used to record radial and axial flame spreading. Experiments were conducted for three different igniter designs. Significant differences in the flame spread history for the three igniters were found and the technique proved to be suitable for optimization of ignition systems. Results of the experimental study could be used to validate interior ballistic model predictions.
Time calculation for the after‐cure cooling process of the cast modified double base propellant in a large rocket motor
Authors: Zhanning Jia 
Published: December 2004

AbstractAn unsteady heat conduction model is proposed to calculate the temperature distribution of the case‐bonded rocket motors and the time required for the cooling process based on the experimentally determined thermal and mechanical parameters of a cast modified double base propellant (CMDB) and its glass steel shell. The resultant value of the time is then used to derive the corresponding stress relaxation modulus, which is compared with the modulus data obtained from uniaxial tensile stress relaxation experiments to see if the internal stress has been thoroughly relaxed within this period of time.
Transport and magnetotransport properties of cold‐pressed CrO2 powder
Authors: Liu H. , Zheng R. K. , Wang Y. , Bai H. L. , Zhang X. X. 
Published: December 2004

AbstractResistivity of cold‐pressed CrO2 powder has been measured over the temperature range of 2 to 350 K with a magnetic field up of to 50 kOe. High resolution transmission electron microscopy (HRTEM) images show that the CrO2 particles are needle‐shaped with an aspect ratio of 7:1 and have an average length of 200 nm, and are covered with an ultra‐thin (∼2.5 nm) native Cr2O3 layer. Temperature dependent conductivity can be well described by the expression below 55 K, a feature of electron tunneling, and by the higher‐order hopping for temperature above 55 K. The magnetoresistance, , reaches ∼33.5% at 2 K and decreases to nearly zero at room temperature. Temperature dependent saturation magnetization follows well the relation below 240 K. The spin‐wave stiffness constant, D, is estimated to be ∼91 meV Å2. By fitting the specific heat measured in the temperature range of 1.8–34 K by the relation , we obtained the electronic specific heat coefficient γ = 1.7 mJ/mol K2, this corresponds to a density of states at the Fermi level of 0.73 states/eV, which is in good accordance with the theoretical value of 0.69 states/eV.
Hohenberg–Kohn theory including spin magnetism and magnetic fields
Authors: Kohn Walter , Savin Andreas , Ullrich Carsten A. 
Published: December 2004

AbstractBeginning with work by U. von Barth and L. Hedin in 1972 and continuing with recent papers in 2001 by K. Capelle and G. Vignale and by H. Eschrig and W. E. Pickett, questions have been raised about the meaning and validity of Hohenberg–Kohn theory when spin magnetism and/or magnetic fields are present. This article offers clarifications of some of these questions. In particular, it also concludes that these questions do not affect spin‐density functional theory for nondegenerate ground states as currently practiced. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Quantitative electron spectroscopy of surfaces: A standard data base for electron inelastic mean free paths in solids
Authors: Seah M. P. , Dench W. A. 
Published: December 2004

AbstractA compilation is presented of all published measurements of electron inelastic mean free path lengths in solids for energies in the range 0–10 000 eV above the Fermi level. For analysis, the materials are grouped under one of the headings: element, inorganic compound, organic compound and adsorbed gas, with the path lengths each time expressed in nanometers, monolayers and milligrams per square metre. The path lengths are vary high at low energies, fall to 0.1–0.8 nm for energies in the range 30–100 eV and then rise again as the energy increases further. For elements and inorganic compounds the scatter about a ‘universal curve’ is least when the path lengths are expressed in monolayers, λm. Analysis of the inter‐element and inter‐compound effects shows that λm is related to atom size and the most accuratae relations are λm = 538E−2+0.41(aE)1/2 for elements and λm=2170E−2+0.72(aE)1/2 for inorganic compounds, where a is the monolayer thickness (nm) and E is the electron energy above the Fermi level in eV. For organic compounds λd=49E−2+0.11E1/2 mgm−2. Published general theoretical predictions for λ, valid above 150 eV, do not show as good correlations with the experimental data as the above relations.
Mean free path for inelastic scattering of 1.2 kev electrons in thin poly(methylmethacrylate) films
Authors: Roberts R. F. , Allara D. L. , Pryde C. A. , Buchanan D. N. E. , Hobbins N. D. 
Published: December 2004

AbstractMean free paths for inelastic scattering (λ) of low energy electrons in poly(methylmethacrylate) (PMMA) have been determined by measuring Al Kα excited C 1s and Si 2s photoelectron signal intensities as a function of ellipsometrically determined thicknesses of PMMA overlayers on silicon substrates. The λ values obtained are 29 ± 4 Å for 1196 eV electrons and 33 ± 5 Å for 1328 eV electrons. These data are necessary for the quantitative analysis of the surface region of PMMA and similar polymers by X‐ray photoelectron spectroscopy (XPS). The magnitude of the λ values determined indicates that XPS measurements can provide chemical information about the surface region of polymers, such as PMMA, in the depth range of ∼6 to 100 Å. The results of this study are compared and discussed with respect to λ values determined for other organic compounds.
Determination of relative transmission function of two scanning modes of an electrostatic hemispherical analyser with a lens system
Authors: Richter K. , Peplinski B. 
Published: December 2004

AbstractEvidence is provided, that the transmission function Tp,a of an electrostatic hemispherical analyser with a lens system, operated at fixed transmission energy (FATE mode) relative to that for operation at fixed retarding ratio (FRR mode) varies with kinetic energy E according to E−1.25 (400 eV < E < 1470 eV).
X‐ray photoelectron study of surface compounds formed during flotation of minerals
Authors: Nefedov V. I. , Salyn Ya. V. , Solozhenkin P. M. , Pulatov G. Yu. 
Published: December 2004

AbstractThe compounds formed on the surface of minerals under the action of flotation reagents have been studied by ESCA. On a ZnS surface treated with CuSO4 solution, Cu2S and SO were identified. The quantity of Cu2S increased and that of SO decreased with increased Fe content in ZnS. After treatment of PbS with K2Cr2O7 solution, a combination of Cr2O3 and Pb(OH)2, or PbCr2O4 was formed on the surface. The action of Pb(NO3)2 solution on Sb2S3 led to the formation of PbSb2S4 type compounds. HgO or HgS were formed on an Sb2S3 surface after treatment with (C2H5)2NC6H4HGOCOCH3 solution. In all cases excluding the PbS and K2Cr2O7 system the quantity of products formed on the surface increased with reagent concentration.
X‐ray photoelectron spectroscopic and electron spin resonance studies of cobalt species in CoMo/γ‐Al2O3hydrodesulfurization catalysts after operation for eight hours under pressure
Authors: Gajardo P. , Grange P. , Delmon B. 
Published: December 2004

AbstractWe report X‐ray photoelectron spectroscopic and electron spin resonance data on Co/γ‐Al2O3and CoMo/γ‐Al2O3catalysts Co/(Co+Mo) = 0.35 after sulfidation and catalytic operation under 30 bars pressure at 305°C for eight hours. The catalysts were protected from air contamination. Data on catalytic activity (hydrogenolysis of thiophene and hydrogenation of cyclohexene), X‐ray diffraction and diffuse reflectance spectroscopy are also reported. A reduced cobalt species is associated with Co9S8on Co/γ‐Al2O3. This species is not detected on CoMo/γ‐Al2O3, where cobalt occurs as CoAl2O4and as cobalt in a fully sulfided form, quite probably as Co9S8. If the hypothesis of the synergy by contact is correct, the results indicate that unreduced Co9S8is the activating agent.
Empirical atomic sensitivity factors for quantitative analysis by electron spectroscopy for chemical analysis
Authors: Wagner C. D. , Davis L. E. , Zeller M. V. , Taylor J. A. , Raymond R. H. , Gale L. H. 
Published: December 2004

AbstractQuantitative information from electron spectroscopy for chemical analysis requires the use of suitable atomic sensitivity factors. An empirical set has been developed, based upon data from 135 compounds of 62 elements. Data upon which the factors are based are intensity ratios of spectral lines with F1s as a primary standard, value unity, and K2p3/2 as a secondary standard. The data were obtained on two instruments, the Physical Electronics 550 and the Varian IEE‐15, two instruments that use electron retardation for scanning, with constant pass energy. The agreement in data from the two instruments on the same compounds is good. How closely the data can apply to instruments with input lens systems is not known. Calculated cross‐section data plotted against binding energy on a log‐log plot provide curves composed of simple linear segments for the strong lines: 1s, 2p3/2, 3d5/2 and 4f7/2. Similarly, the plots for the secondary lines, 2s, 3p3/2, 4d5/2 and 5d5/2, are shown to be composed of linear segments. Theoretical sensitivity factors relative to F1s should fall on similar curves, with minor correction for the combined energy dependence of instrumental transmission and mean free path. Experimental intensity ratios relative to F1s were plotted similarly, and best fit curves were calculated using the shapes of the theoretical curves as a guide. The intercepts of these best fit curves with appropriate binding energies provide sensitivity factors for the strong lines and the secondary lines for all of the elements except the rare earths and the first series of transition metals. For these elements the sensitivity factors are lower than expected, and variable, because of multi‐electron processes that vary with chemical state. From the data it can be shown that many of the commonly‐accepted calculated cross‐section data must be significantly in error—as much as 40% in some cases for the strong lines, and far more than that for some of the secondary lines.