bluuebunny/crossref_metadata_2025_split huggingface dataset:
X‐Ray Microanalysis on the Surface and Cross‐Section of burning‐interrupted aluminum particle and foil in high pressure atmospheres
Authors: Tokui H. , Iwama A. 
Published: December 2004

AbstractIn order to deduce the burning characteristics of aluminum (Al) particle in solid propellant, a model experiment has been carried out with Al spheres of 3 mm ∼4 mm dia. in the oxidizing atmospheres at elevated pressures. As one of the investigation items, X‐ray microanalysis for the burning‐interrupted Al spheres was conducted along the straight lines crossing cap‐like Al2O3 islands attached on unburned Al.It was clarified that, on the way of burning, in the case of Al sphere and plausibly on the burning surface of the particle also, there exist numerous Al2O3 islands, large and small, floating on molten Al sea; but even on the sea part, which seemed pure Al only, the surface is covered mostly with Al2O3 film. The similar analysis was applied to the Al foils ignited with Joule heating. It was witnessed, however, that contrary to the sphere surface there remains still neat Al in the vicinity of burning‐interrupted surface. This fact may introduce low ignition temperature (933 K ∼ 963 K) and high deflagration velocity along the surface (for example. 2500 mm/s, with test piece of 0.11 mm thick, 5 mm wide; 8 MPaO2 ) with Al foils.
Aging of Pyrotechnik Compositions. The investigation of chemical changes by IR spectroscopy and x‐ray diffraction
Authors: Barišin D. , Batinić‐Haberle I. 
Published: December 2004

AbstractThe aging of tracers, containing different amounts of Mg, Sr(NO3)2, KClO4, Al‐Mg alloy and organic binder, was conducted under the conditions of 50.0% and 98.5% relative humidities at 75 °C, and of 98.5% relative humidity at 25 °C. IR spectroscopy and X‐ray diffraction were used for investigation of chemical changes. At the lower humidity no detectable changes were observed. Tracer of metauoxidant ratio >1 exhibits decreased stability, changing significantly under the conditions of higher humidity, even at room temperature. In the reaction sequence of aging process (Mg(OH)2) and SrCO3 are formed, with concomitant decrease in Mg and Sr(NO3)2 content. Alloy changes only slightly, and the content of KClO4 and binder remains unchanged. Interaction between metal and nitrate is considered to be essential in the process of chemical aging.
The Effect of the Liner Metallurgical State on the shaped charge jet break‐up time
Authors: Hirsch Eitan 
Published: December 2004

AbstractThe effect of the liner metallurgical state on the shaped charge jet break‐up time has been widely investigated experimentaly but the experimental results were never explained by a model sufficiently detailed to even explaining them qualitatively. The model presented here shows for the first time a direct mathematical connection between the Vpl break‐up parameter and the processes which affect the liner metallurgical state during the initial stages of the flow: the drive of the liner by the explosive and the jet formation. The model shows how both the deformation energy heating the sliding shear bands during the localization process and the rate of the instability growing in the plastic flow during this process, combine to determine the Vpl parameter. This parameter is then shown to be both the velocity of the information of the plastic deformation and the component of the maximum slide velocity allowable to shear band in the elongation direction. The model predicts the shaped charge jet segment normalised length over diameter (L/D) distribution with good accuracy. It also explains the pattern of shear bands observed on the surface of jet segments recovered by Zernow, including their width. Furthermore, the model is strongly supported by its ability to show good agreement between measurements of aluminum dynamical elongation obtained in different ways, which were so far believed to be unrelated. When the jet temperature measurements by Von Holle and Trimble are reinterpreted in view of the model it is found that the average jet temperature is lower than the value they found and the temperature basically agrees with Racah's predictions.
Carbon resistor gauges for measuring shock and detonation pressures. I. Principles of functioning and calibration
Authors: Austing James L. , Tulis Allen J. , Hrdina Donald J. , Baker Douglas E. , Martinez Ricardo 
Published: December 2004

AbstractThe state of the art relative to the measurement of shock and detonation pressures of the magnitude generaled by condensed high explosives is reviewed. Carbon resistors have been shown to provide a relatively inexpensive and direct method for such measurements, provided adequate calibration data are available. The gauge is fabricated by heat‐sealing the carbon resistor (470 Ω, 0.125 W) into a suitable plastic material such as polystyrene; when subjected to a strong shock wave, the gauge undergoes compression and the conductivity increases in proprtion to the magnitude of the pressure. The present investigation was concerned with the experimental derivation of calibration equations relating the pressure (in gigapascal) as a function of the conductivity change ΔG (in siemens). The point of inflaction occurring at approximately 2.36 GPa, corresponding to 0.02082 S, is in agreement with previous observations in the literature. Additional experiments are being planned to resolve a problem concerning oscillatory ringing in the gauge voltage records.
Stabilizer reactions in cast double base rocket propellants. Part I: HPLC Determination of Stabilizers and their derivatives in a propellant containing the stabilizer mixture para‐nitro‐N‐methylaniline and 2‐nitrodiphenylamine aged at 80°C and 90°C
Authors: Bellerby J. M. , Sammour M. H. 
Published: December 2004

AbstractReverse phase high performance liquid chromatography (HPLC) employing an acctonitrile/methanol/water (45/10/45) mobile phase has been used to separate and quantitate the stabilizaers para‐nitro‐N‐methylaniline, (pNMA) and 2‐nitrodiphenylamine, (2NDPA) and their derivatives in a mixed‐stabilizer cast double hase rocket propellant composition undergiong acceterated aging at 80°C adn 90°C. Quantitative measurements show that pNMA is converted almost cntirely into N‐nitroso‐pNMA during the carly stages of aging and that this derivative persists for the remainder of the aging period. 2NDPA, on the other hand, reacts more slowly to give both N‐nitroso and C‐nitro derivatives.
Shock Initiation of Sheet Explosive
Authors: Yadav H. S. , Nath T. , Sundaram S. G. , Kamath P. V. , Kulkarni M. W. 
Published: December 2004

AbstractThe shock sensitivity of a typical sheet explosive RDX‐WAX (90:10) has been experimentally determined with gap test arrangement by measuring free surface velocity in different thicknesses of the barrier and shock and particle velocity of non‐reactive shock wave in the sheet explosive with Pin Oscillography Technique. It has been found that a shock wave, generated by a point‐initiated cylindrical explosive in contact with an aluminium barrier of diameter nearly twice the diameter of the charge, attenuates exponentially and a 6.5 mm thick sheet explosive, of density 1.28 g/cm3 and velocity of detonation 6.43 mm/μs, detonates with 50% probability by a shock wave of 11 kbar pressure in the explosive.
The thermal stability of the polymorphs of hexanitrohexaazaisowurtzitane, part II
Authors: Foltz M. Frances , Coon Clifford L. , Garcia Frank , Nichols Albert L. 
Published: December 2004

AbstractSolid‐solid phase transitions in the α‐, β‐, γ‐, and ϵ‐polymorphs of 2,4,6,8,10,12‐hexanitrohexaazaisowurtzitane (HNIW) have been studied as a function of temperature. Techniques employed include differential scanning calorimetry (DSC), differential thermal analysis/thermogravimetric analysis (DTA/TGA), and hot stage microscope analysis. Fourier transform infrared spectroscopy (FTIR) was used to identify results of polymorphic conversion. Results corroborate those(2) of Part I that the existence of multiple α‐hydrate phases complicates definition of the HNIW P‐T phase diagram. A high temperature endothermic DSC response was determined by FTIR spectroscopy to be the β → γ transition, not a conversion to a new high temperature “delta” phase. The role of water in the shifting this conversion to higher temperature is discussed.
Estimation and prediction of the heats of formation for non‐aromatic polynitro compounds on the basis of the QSPR approach
Authors: Sukhachev Dmitrii V. , Pivina Tatyana S. , Volk Fred S. 
Published: December 2004

AbstractThe analysis of “Quantitative Structure‐Property Relationship”(QSPR), concerning the heat of formation in the condensed state, is performed for non‐aromatic polynitrocompounds. The QSPR approach and our original computer program “EMMA”(Efficient Modelling of Molecular Activity) are used. This approach is based on the construction of optimal linear regression models involving physical‐chemical, topological, informational, and substructural indices; it can be used as an alternative to traditional additive schemes for evaluating physical‐chemical characteristics of energetic materials. On the basis of the QSPR method, the “structure‐heat of formation (ΔH°f)” relationship is revealed for a data base of non‐aromatic polynitrocompounds, and ΔH°f is predicted for some hypothetic substances.
Stabilizer reactions in cast double base rocket propellants. Part VI: Reactions of propellant stabilizers with the known propellant decomposition products NO2, HNO2, and HNO3
Authors: Sammour M. H. , Bellamy A. J. 
Published: December 2004

AbstractThe reactions of stabilizers with the individual reactive species known to be generated during double base propellant decomposition, viz. NO2, HNO2 and HNO3, have been thoroughly investigated in an attempt to obtain information on the reactions that take place in these propellant systems. It was found that the various stabilizers differ in their behaviour towards these reactive species, and this should help to give a clearer picture of the chemistry occuring during aging of double base propellants.
Plateau Burning Characteristics of AP Based Azide Composite Propellants
Authors: Oyumi Yoshio , Anan Toshiyuki , Bazaki Hakobu , Harada Tadamasa 
Published: December 2004

AbstractThe site and mechanism by which iron oxide catalyst acted to enhance burning rate and produced plateau burning behavior at high pressure was studied. The condensed phase chemistry study was conducted by isothermal thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), and rapid‐scan FTIR spectroscopic technique. Uncatalyzed ammonium perchlorate (AP) based azide composite propellant showed unstable combustion at relatively lower pressure region. The heat balance at the buring surface would be unstable at these pressures. However, iron oxide altered the burning property of the propellant and enhanced the burning rate with the plateau‐mesa burning characteristics. Such pressure insensitiveness of the burning rate indicated that the condensed phase chemistry played important role in the catalytic mechanism of action. According to the microrocket motor tests, physical effect, melted fuel binder covered the AP particles and prevented the further decomposition of AP, had not affected the plateau burning. Fe2O3 was more effective on the burning rate augmentation than Fe3O4. However, the pressure exponent of the burning rate point of view Fe3O4 was favored catalyst to the propellant used here.
Carbon resistor gauges for measuring shock and detonation pressures. III. Revised calibration data and relationships
Authors: Austing James L. , Tulis Allen J. , Joyce Richard P. , Foxx Carl E. , Hrdina Donald J. , Bajzek Thomas J. 
Published: December 2004

AbstractFor many years, carbon resistors have formed the basis for measurement of shock and detonation pressures associated with condensed explosives. The gauge is fabricated by heat‐sealing the resistor into a plastic material such as polystyrene. When subjected to a strong shock wave, the resistance decreases, and the resulting increase in conductance is a function of the magnitude of the pressure. The present investigation was concerned with the experimental derivation of revised calibration equations, which was necessitated by the need to incorporate a terminating resistor into the gauge circuitry. The use of this resistor decreased the effect of standing waves and eliminated oscillatory ringing in the recorded signal. Typical records over a wide range of pressures are presented. An error analysis of the recorded data showed that the uncertainty in the measured pressure was of the same order of magnitude as the uncertainty in the interpretation of the recorded voltage from which the conductance was computed. An extensive discussion of the relevancy of the experimental data is presented, and the need for additional calibration experiments is stressed.
On the inconsistency of the asymmetric‐sandwich gurney formula when used to model thin plate propulsion
Authors: Hirsch Eitan 
Published: December 2004

AbstractThe asymmetric sandwich Gurney formula is used extensively worldwide during explosive reactive armor and shaped‐charge war‐head design, in either its original form(1,2) or its extended form used to model implosion configurations(3–5). It is therefore very important to realize that calculations may contradict physical observations when the formula is used to calculate the velocity of thin plates having mass which is smaller than half the explosive mass per unit area. This inconsistency between calculation and experimental results is explained as resulting from the failure of the assumption made in deriving all the Gurney formulas that the velocity distribution of the explosive products is a linear function of the expansion coordinate.
An Analysis of the Influence of Detonator Parameters on the propagation of shock waves in an inert medium
Authors: Cudzilo Stanislaw , Maranda Andrzej , Nowaczewski Jerzy , Trzciński Waldemar 
Published: December 2004

AbstractThe effect of mass, diameter and type of detonator on parameters of shock waves generated in plexiglas block is examined by experimental and theoretical means. The quantities connected with the shock wave, such as, the mean velocity of the shock wave front, the profile of mass velocity behind this front, and the mean velocity of free surface of the loaded block are measured.To perform an numerical analysis of the shock wave parameters mentioned above on type and size of detonator the problem is considered of acting of detonation products of an explosive charge on a block of inert material. In this goal, the active mass of charge is determined and, next, the model assumptions and mathematical formulation of the problem of penetration of pressure pulse into inert medium are presented. The results of computer simulation and experimental data are compared.
LX‐17 Corner‐Turning
Authors: Souers P. Clark , Andreski Henry G. , Cook Charles F. , Garza Raul , Pastrone Ron , Phillips Dan , Roeske Frank , Vitello Peter , Molitoris John D. 
Published: December 2004

AbstractWe have performed a series of highly‐instrumented experiments examining corner‐turning of detonation. A TATB booster is inset 15 mm into LX‐17 (92.5% TATB, 7.5% kel‐F) so that the detonation must turn a right angle around an air well. An optical pin located at the edge of the TATB gives the start time of the corner‐turn. The breakout time on the side and back edges is measured with streak cameras. Three high‐resolution X‐ray images were taken on each experiment to examine the details of the detonation. We have concluded that the detonation cannot turn the corner and subsequently fails, but the shock wave continues to propagate in the unreacted explosive, leaving behind a dead zone. The detonation front farther out from the corner slowly turns and eventually reaches the air well edge 180° from its original direction. The dead zone is stable and persists 7.7 μs after the corner‐turn, although it has drifted into the original air well area. Our regular reactive flow computer models sometimes show temporary failure but they recover quickly and are unable to model the dead zones. We present a failure model that cuts off the reaction rate below certain detonation velocities and reproduces the qualitative features of the corner‐turning failure.
Atomic Force Microscopy study of hexagonal boron nitride film growth on 6H‐SiC (0001)
Authors: Chen Wei , Ping Loh Kian , Lin Ming , Liu Rong , Wee Andrew T. S. 
Published: December 2004

AbstractBoron nitride thin films with their unique mechanical and electrical properties are of interest for various applications and have been grown on a number of different substrates. The cover picture from this issue's Editor's Choice [1] shows an Atomic Force Microscopy topography of a hexagonal BN film grown on 6H‐SiC substrate by Plasma Enhanced Chemical Vapor Deposition at 600 °C. Interesting stress‐relief features developed on the non‐reactive substrate.	The corresponding author Kian Ping Loh is Assistant Professor at the National University of Singapore. His research is devoted to the growth of diamond and boron nitride thin films and the fabrication of nanocrystalline diamond and boron nitride nanotubes.As a follow‐up to the recent special issue on ‘Physics of Organic Semiconductors’ [2], Detlef Berner gives insights into organic light emitting diode functioning by coordinated experiment and simulation in his Review Article [3].The present issue also sees the start of our rapid research letters, the fastest peer‐reviewed publication medium in solid state physics. For more information see www.pss‐rapid.com and the Editorial by the Editor‐in‐Chief Martin Stutzmann on page 7 [4].
Synthesis and Radiochemical Labeling of N‐(2,6‐Diisopropylacetanilido)‐Iminodiacetic Acid and Its Analogues under Microwave Irradiation: A Hepatobiliary Imaging Agent
Authors: Park Sang Hyun , Gwon Hui Jeong , Park Jeong Sook , Park Kyung Bae 
Published: December 2004

AbstractThis paper describes a fast and convenient procedure for the synthesis of 2,6‐diisopropylacetanilidoiminodiacetic acid and its analogues and radiochemical labeling with 99mTc. They were synthesized in large scale under microwave irradiation in very short reaction times. A microwave reactor offers a rapid and efficient methodology for the formation of a considerable range of IDA derivatives. The method is expected to be applicable to the preparation of radiopharmaceuticals.
Microwave‐assisted aza‐Baylis‐Hillman Reaction. Preparation of Poly(ethylene Glycol) Supported α‐methylene‐β‐Aminoester
Authors: Ribière Patrice , Yadav‐Bhatnagar Neerja , Martinez Jean , Lamaty Frédéric 
Published: December 2004

AbstractThe aza‐Baylis Hillman is a practical method for the preparation of α‐methylene‐β‐aminoesters. A soluble polymer supported version of this reaction has been developed. The reaction was shown to proceed in the absence of solvent under microwave activation. In the presence of 3‐hydroxyquinuclidine, the reaction time was reduced from 3–12 h under thermal conditions to 30 min under microwave irradiation. A small library of PEG‐supported aminoesters was generated.
Microwave‐assisted Synthesis of a 3‐Aminoimidazo[1,2‐a]‐pyridine/pyrazine Library by Fluorous Multicomponent Reactions and Subsequent Cross‐coupling Reactions
Authors: Lu Yimin , Zhang Wei 
Published: December 2004

AbstractMicrowave and fluorous technologies are employed to increase reaction speed and reduce separation time in solution‐phase parallel synthesis of a substituted 3‐aminoimidazo[1,2‐a]pyridine and 3‐aminoimidazo[1,2‐a]pyrazine library. Multicomponent reactions of perfluorooctanesulfonyl‐tagged benzaldehydes with 2‐aminopyridines (or 2‐aminopyrazines) and isocyanides are followed by Pd‐catalyzed cross‐coupling reactions with boronic acids or thiols to form biaryls or aryl sulfides. Reaction mixtures are purified by fluorous solid‐phase extraction (F‐SPE) or crystallization.
Improved depth resolution in Auger depth profiling of multilayered thin films by reactive ion sputtering
Authors: Blattner R. J. , Nadel S. , Evans C. A. , Braundmeier A. J. , Magee Charles W. 
Published: December 2004

AbstractReactive ion sputtering (N) is shown to improve depth resolution significantly in conventional Auger electron spectroscopy depth profiling of multilayered metallic thin film samples as compared to standard argon ion bombardment. Layer modulations on the order of the escape depth of the Auger electrons are shown to be discernible by conventional Auger depth profiling in a texturing‐prone situation (microscopically modulated thin film samples) when N is used as the sputtering species. Oxygen ion sputtering was observed to give greater improvement in depth resolution than nitrogen, but was also observed to have a deleterious influence on instrument performance. Increasing the N ion energy from 2 to 5 Ke V was found to degrade depth resolution slightly.
The coadsorption method in Auger electron spectroscopy: Applications to the analysis of contaminated nickel surfaces
Authors: Oda O. , Read G. E. 
Published: December 2004

AbstractThree examples of applications of the coadsorption technique using a metal monolayer ‘étalon’ in AES are described. They concern adsorption of tin on nickel (100) surfaces partially contaminated with lead, phosphorus or oxygen. The results extend an earlier account and point to some new phenomena (desorption stimulated by the metal vapour, complex variations in sticking probability, multiplayer growth, adsorbate diffusion) that can be examined using this technique.
Studies of the metal–support interaction in coprecipitated nickel on alumina methanation catalysts using X‐ray photoelectron spectroscopy (XPS)
Authors: Shalvoy R. B. , Davis B. H. , Reucroft P. J. 
Published: December 2004

AbstractCharacterization studies on a series of coprecipitated alumina‐supported nickel methanation catalysts by X‐ray photoelectron spectroscopy are described. Binding energies and spectral shapes have been determined for several standard compounds (Ni, NiO, Ni(OH)2, NiAl2O4, Al2O3) to provide background information for interpreting the catalyst spectra. The results indicate that the surface regions of the fresh (unreduced) catalysts are composed primarily of amorphous NiAl2O4 with some NiO particles present either within the pores of the support or covered by a NiAl2O4 layer. In comparison with similarly prepared silica‐supported catalysts, reducibility is more difficult indicating the presence of stronger support interactions.
Calculations of the backscattering factor for L3MM Auger transitions
Authors: Jabłoński Aleksander 
Published: December 2004

AbstractThe single scattering Monte Carlo algorithm of Murata, Matsukawa and Shimizu and the Gryziński ionization cross‐section were used in calculations of the backscattering factor r. The calculations were based on two definitions of r. Generally, the backscattering factor was defined as the ratio of the Auger electron current recorded by the analyser to the current that would be recorded in the ideal case of no backscattering and no energy loss. The usual definition, involving the energy distribution of backscattered electrons, was also used. The calculations were performed for L3MM Auger transitions of elements with atomic numbers between 23 and 32. The primary energy ranged from 3 to 10 keV. The difference in backscattering factors resulting from both definitions varied from 0.1% to 10%, decreasing with the primary energy increase. The single scattering Monte Carlo algorithm can also be used in simulation of electron scattering in binary alloys. This makes possible the calculation of the backscattering factor as a function of the solid composition. The calculations were performed for L3MM Auger transitions of Cr, Cu, Fe and Ni in Au/Ni, Cr/Fe, Cr/Pd, Cu/Ni and Ni/Pd binary alloys. It was found that the backscattering factor varies almost linearly with mass fraction. The dependence on concentration is more pronounced when the difference in atomic numbers of alloy components is larger. The relative sensitivity factors, calculated for Cu/Ni and Cr/Fe binary alloys, are practically independent of composition, but depend on the primary energy.