bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of the Combustion of Liquid Gun Propellants in Closed Chambers
Authors: Klingenberg G. , Knapton J. D. , Watson C. 
Published: December 2004

AbstractClosed chamber tests on hydroxylammonium nitrate (HAN) based liquid monopropellants (LPs) were performed at loading densities of about 0.2 g/cm3 at both the Fraunhofer‐Institut für Kurzzeitdynamik (EMI‐AFB), and the Ballistic Research Laboratory (BRL). The objective of the studies was to investigate the decomposition of the HAN based liquid propellants under various conditions. Pressure and temperatures were measured for both neat and intentionally contaminated monopropellants. Contaminants tested were iron, copper, aluminum, and nickel at concentrations of about 100 ppm. The temperatures were determined using both thermocouples and specially designed temperature (emission) gages. The data illustrate the behavior of the liquid propellants during the decomposition phase.
Burning Behavior of Composite Solid Propellant containing porous ammonium perchlorate
Authors: Leu An‐Lu , Yeh Tsao‐Fa , Chang Fang‐Mo , Liu Chao‐Shih , Huang Chen‐Chia , Liu Fang , Shih Yu‐San 
Published: December 2004

AbstractA pilot scale fluidized bed process was developed for preparing porous ammonium perchlorate (PAP) in various particle sizes. The oxidizer, ammonium perchlorate (AP), of composite solid propellant was partially replaced by PAP which was obtained by the fluidization process. The burning rate of propellants containing PAP was found to increase as compared with that of propellants without PAP. In the present study, the effects of percentage content and particle size of PAP incorporated in propellant compositions, on the burning rate were investigated. The results showed that the burning rate increases with increasing of PAP content and with decreasing of PAP particle size for trimodal oxidizer propellants.
Combustion of Gas‐Permeable Porous Systems
Authors: Frolov Yu. V. , Korostelev V. G. 
Published: December 2004

AbstractThe process of combustion of gas‐permeable porous systems when there is a pressure drop at the inlet into pores has been studied. The dynamics of processes during one‐dimensional and non‐dimensional combustions has been analyzed.Conditions for stabilization of combustion rates are revealed. Analytical expressions are found to determine main parameters in combustion of gas‐permeable systems with non‐melting components and relatively narrow pores.
Evaluation of various stabilizers for Stability and Increased Life of CMDB Propellants
Authors: Asthana S. N. , Deshpande B. Y. , Singh H. 
Published: December 2004

AbstractThis study establishes superiority of resorcinol as stabilizer for CMDB propellants followed by RDME (resorcinol dimethylethcr) as compared to other resorcinol derivatives and that of CdO amongst metal oxides. The use of resorcinol and CdO combination in CMDB formulation results in higher E of 33 kca/mol and shelf life of 203 years as compared to E of 31 kcal/mol and life of 70–73 years for resorcinol or CdO based composition suggesting their synergistic stabilization effect. Results of the present investigation bring out that aging mechanism of CMDB involves cleavage of RO‐NO2 bond like DBP, however, AP‐based CMDB are strongly autocatalytic. Thus stabilizers used in DBP (Carbamite and 2‐NDPA) do not take care of CMDB propellant aging. Suitability of resorcinol may be explained on the basis of its activated aromatic ring for scavenging of oxides of nitrogen.
Kinetics of Dehydration of Guanidine Nitrate in H2SO4/HNO3/H2O ternary mixtures
Authors: Liu Tai‐Kang , Shyr Yan‐Nian , Ho Chan‐Yuan 
Published: December 2004

AbstractA nitroguanidine process development study was performed by investigating the kinetics of dehydration of guanidine nitrate in 81% H2SO4/5% HNO3/14% H2O ternary mixtures. An irreversible second order apparent kinetic model lumping both dissolution resistance and chemical reaction resistance was obtained from analysis of the experimental data, and was used to predict the performance of the cascade CSTR and semi‐batch reactor under some feasible conditions. The predicted yields are in reasonably good agreement with the ones from experimental measurements. A reaction mechanism was proposed and was shown to reasonably elucidate the observed rate phenomena.
Combustion Aspects of Sodium Azide and its mixtures with potassium perchlorate and burning catalysts
Authors: Hasue Kazuo , Iwama Akira , Kazumi Takashi 
Published: December 2004

AbstractLinear burning rate, thermal aualysis, temperature profile, flame structure and cryogenic burnability for the mixtures of sodium azide (SA) of different particle sizes (3.5 μm, 22 μm, and 67 μm), potassium perchlorate (KP) and with or without three kinds of burning catalysts (GeO2, Er2O3, and Y2O3) have been investigated. The linear burning rates increase with the KP content up to 33Wt% for similar SA particle size. The temperature‐time histories in the vicinity of burning surface were obtained with 20 μm Type K thermocouple embedded in a Strand. The burning surface temperaturres of neat SA and of the SA/KP mixtures are nearly 350°C and 350°C ∼ 550°C, respectively, while the existence of the decomposition surface at 250 °C and condensed layer was suggested with SA/KP mixtures. In visual observation for the flame structure, the front of luminous flame zone appers to be in contact with the condensed phase surface. For example, however, the temperature profile suggests that there exists finitc distance from decomposition surface to flame front in the order of 0.05 mm ∼ 0.1 mm at 1 MPa for SA/KP = 80/20. The differential thermal analysis indicates that the tested catalysts have retarding effect on SA combustion, but a positive effect on neat KP decomposition in spite of being impotent for the burning rate increase of the SA/KP mixture. It was also found that SA strands containing appropatiae fractions of KP can hurn even in liquid nitrogen.
New dependence of Activation Energies of Nitroesters Thermolysis and possibility of its application
Authors: Zeman Svatopluk 
Published: December 2004

AbstractRelationship was found between activation energies E of low‐temperature non‐autocatalyzed thermolysis of the nitric acid esters, on the one hand and their oxygen balances OB100, on the other. By this relationship, molecular‐structural dependence is evidenced of values E, at the same time existence is signalized of the direct relationship between the values E and the impact sensitivity of nitroesters.
Numerical Simulation of Casting Explosives in Shell
Authors: Chen Chun‐Yu , Shiuan Jonq‐Hwa 
Published: December 2004

AbstractPredicting interface position of solid‐liquid phase change is important for the filling of explosives in the shell. The cooling process of casting charge is discussed analytically and experimentally. The basic equations describing this process are derived from a modified and extended equivalent heat capacity model. Numerical calculations are then performed to determine the solidification front distributions and temperature distributions. The experiments are performed using TNT as the phase change material. Comparison between practical experiments and computer simulation has shown that there is a good agreement. By using computer calculations, a better knowledge of important parameters for the casting process can be easily obtained.
A Simple Model for Jet Formation in Shaped Charges
Authors: Jones David A. 
Published: December 2004

AbstractA simple model capable of reproducing all of the experimental results known for the MRL 38 mm diameter shaped charge is described. The basis of this model is the original analytical work of F'ugh, Eichelberger and Rostoker and the more recent work of Hirsch, and of Carleone, Jameson and Chou. The three phenomenological constants required by the model are found by fitting to data from the BRL 105 mm diameter unconfined shaped charge. The model is then used to calculate the jet velocity gradient and the collapse angle versus time for the MRL standard charge. Good agreement has been found with recent experimental results.
The Equation of State of Detonation Products obtained from cylinder expansion test
Authors: Chen Chun‐Yu , Shiuan Jong‐Hwa , Lan I‐Feng 
Published: December 2004

AbstractThe equation of state of detonation products is essential to the explosive application. The study of this paper is set up with the following procedures: (1) cylinder expansion test is performed in a detonation test chamber, and the radial expansion, varied with time, of copper tube which is filled with Composition B, is recorded by Hamamatsu streak camera, (2) the JWL parameters are obtained by means of a simple mathematical analysis, and (3) the 2DL Code has been modified using JWL equation of state instead of HOM equation of state to study the behavior of the detonation gases. The results show that the JWL parameters of this study are in close agreement with the LLNL's approach and the JWL equation of state can more accurately predict the behavior of detonation products than the HOM.
Relationships between Electron Structures of N‐Methylolamines and their Reactivity in the mannich reaction
Authors: Zhang Yuejun , Dong Wei , Shi Jie , Li Weimin 
Published: December 2004

AbstractThe electron structures of various unstable N‐methylolamines and their imine cations formed during the urotropine nitrolysis process were studied by SCF‐CNDO/2 computation. The relative tendency of forming imine cations from such N‐methylolamine molecules was assessed by the computation values of Mulliken bond order (Mco) of CO bond and the negative values (−Eco) of two‐atome energy. The electrophilic order of imine cations described by the products (Zco) of carbocation's static charges and the rations of partition functions Qs/Qp between s and p electrons, were used to express the relative reactivity of the Mannich reaction intermediates. Experimental results were satisfactorily explained by the calculated values, and the reactivity of nitrolysis fragments was successfully predicted by the defined values.
The Influence of the Various Types of Binder on the burning characteristics of the magnesium‐, boron‐, and aluminum‐based igniters
Authors: Barišin Dubravka , Batinić‐Haberle Ines 
Published: December 2004

AbstractThe behaviour of six different types of binders phenol‐formaldehyde resin, shellac, polyvinylchloride, ethylcellulose, nitrocellulose, and fluorel was investigated in pyrotechnic compositions on the basis of magnesium, boron and aluminum. It has been found that the nature of the binder significantly influences the burning characteristics of the igniters. Correlation has been found between binder exothermicity and investigated characteristics. In addition, the influence of the contents of phenol‐formaldehyde resin and of fluorel, in the range of 0% to 25% on the same performance characteristics was studied. Phenol‐formaldehyde resin has been chosen as preferred binder for the investigated igniters in an amount of 5%.
Analysis of 2‐Nitrodiphenylamine and its Major Derivatives in double and triple base propellants
Authors: Kansas L. , Robertson D. 
Published: December 2004

AbstractHigh performance liquid chromatography is used to separate 2‐nitrodiphenylamine and its major reaction products with nitrogen oxide in double and triple base rocket and artillery propellants. A reversed phase, isocratic technique is employed. Analysis of samples stored at ambient and elevated temperatures is discussed.
The Two‐Steps Reaction Zone Structure: A way to interpret non‐ideal detonations observations
Authors: Fauquignon C. 
Published: December 2004

AbstractThe reaction zone of an heterogeneous explosive is the sequence of micro‐thermal explosions followed by a volume combustion until the end of the reactions. It is shown that the physical and geometrical parameters characterizing the explosive play a different and frequently opposite role in the two steps of the reaction zone.
Studies on Burn Rate of Polyvinylnitrate and Effect of Modifiers
Authors: Mishra S. C. , Durgapal U. C. , Pant Jyotsna , Dutta P. K. 
Published: December 2004

AbstractBurn rates of polyvinylnitrate (PVN) without and with addition of 1% by weight of ballistic modifiers, viz. carbon black, lead stearate, lead gallate and lead salicylate, have been determined at different pressures ranging form 10 kg/cm2 to 85 kg/cm2. The burn rate data show deviations from the standard ballistic equations r = a + bp and r = apn. Nearly plateau burning effect is shown, at lower pressure range, by gelatinized PVN, PVN + 1% lead stearate and PVN + 1% lead gallate, whereas mesa burning is shown by PVN + 1% lead gallate (at p = 40 – 50 kg/cm2) and PVN + 1% lead stearate (at p = 70 to 74 kg/cm2).
Photoacoustic Spectroscopy of Some Energetic Materials
Authors: Hasue Kazuo , Nakahara Shoji , Morimoto Jun , Yamagami Tetsuo , Okamoto Yoichi , Miyakawa Toru 
Published: December 2004

AbstractTo find an effective laser source to ignite energetic materials, the absorption spectra of some energetic materials are obtained by means of a photoacoustic spectroscopy (PAS). In this experiment, PAS covers the wavelength region of 400 nm‐1600 nm in which no other conventional method can take absorption spectra for powdered energetic materials. Photoacoustic spectra of 18 energetic materials are reported. In general, energetic materials tested showed peaks in 600 nm–800 nm and 1400 nm–1600 nm ranges. It is found that the energy required to initiate explosives in the case of ruby laser initiation were correlated with their photoacoustic signal intensities.
A Diversity‐Oriented, Microwave‐Assisted Synthesis of 4‐oxo and 4‐chloropyrido[2,3‐d]pyrimidin‐7(8H)‐ones
Authors: Mont N. , Fernández‐Megido L. , Teixidó J. , Kappe C. O. , Borrell J. I. 
Published: December 2004

AbstractA microwave‐assisted protocol for the synthesis of 4‐oxo and 4‐chloropyrido[2,3‐d]pyrimidin‐7(8H)‐ones, 13 and 9 respectively, bearing a carbon substituent at C2 and a chlorine atom at C4 is reported. The introduction of a wide range of substituents at C2 renders this methodology easily amenable to combinatorial chemistry applications. Two examples of further derivatization of compounds 9, substitution by amine and Suzuki coupling, under microwave irradiation are also described.
Quantitative Auger electron spectroscopy: Via the energy spectrum or the differential?
Authors: Seah M. P. 
Published: December 2004

AbstractAs part of an extended study of the quantitative analysis of surfaces by electron spectroscopy at the National Physical Laboratory, the quantification potential of Auger electron spectroscopy is examined in relation to the two modes of recording the spectra: the direct energy spectrum and the more customary differential energy spectrum. It is shown that it is not possible to describe a physically based routine procedure to obtain peak areas from the energy spectrum for Auger electron spectroscopy to be used, in the usual way, with a depth of analysis characterized by present values of the inelastic mean free path. These inelastic mean free paths are appropriate to measurements in the differential mode. The depth of analysis involved in peak areas form the energy spectrum may often be many times greater than these inelastic mean free paths, and may be rather indeterminate and matrix sensitive. In comparison, quantification in the differential mode is properly characterized in its depth of analysis. Quantification in this mode is most accurate in the usual framework of relative sensitivity factors, matrix factors, etc., by measurements at not too high a resolution (5 eV peak‐to‐peak modulation). The effects of peak shape changes, associated with changes in the energy loss structure with matrix, are removed by using the excursion of the negative peak as a measure of intensity instead of the usual peak‐to‐peak value. Other weak peak shape change are absorbed by the 5 eV modulation, whereas strong changes must be allowed for by relative sensitivity factors, etc., appropriate to the new peak shape.
Surface effect on the valence band Auger spectra of metals
Authors: Bose Shyamalendu M. , Foo E‐Ni 
Published: December 2004

AbstractThe shifts of the high energy peaks of the KVV Auger line shape of Li(100) and the L2,3 VV Auger line shape of Al(100) due to surface localization in the presence of a finite work function for the conduction electrons have been calculated. The results are sensitively dependent on the relative values of the distance of the surface afrom the first layer of ions and the mean free path λ of the ejected Auger electrons.
Investigation of the initial stages of oxidation of differently prepared aluminium by SIMS
Authors: Marton D. , Josepovits V. K. , Csanády Á. 
Published: December 2004

AbstractThe initial stages of oxidation of thin evaporated by SIMS. The highest ratio between the AIO+ ion yield at oxygen coverage ∂=0.13 and zero exposure was observed in the case of the thin film sample; moreover, for the diamond‐polished sample this ratio was higher than for the electropolished one. The Al+ ion yield was found to depend on the oxygen uptake and to show a linear function in the range of the oxygen does applied. Calculations were carried out in connection with the sputtering yields of the three differently prepared samples using the ion yield values obtained. The difference between the samples analysed is ascribed to the different oxide content of their surface layers.
A SIMS and AES examination of a Cu/Co/Si alloy
Authors: Pavlyak Ferenc , Perczel I. Vajasdy , Giber János 
Published: December 2004

AbstractThe present paper deals with SIMS and AES examination of the layer structure developing during the annealing of a Cu/Co/Si alloy. It was discovered from the spectra and Auger images that there is a significant local increase of the concentration of the alloying materials. A surface layer develops during heat treatment of the alloy sample. We prove the presence of CoSi clusters and the joint enrichment of Si and Co.
Critical assessment by analytical electron microscopy of the significance of XPS measurements of the dispersion of supported catalysts
Authors: Delannay F. , Houalla M. , Pirotte D. , Delmon B. 
Published: December 2004

AbstractThe use of XPS intensity measurements to monitor the dispersion of supported catalysts becomes questionable in the case of an inhomogeneous repartition of the active species. Analytical electron microscopy permits the measurement of such inhomogeneitis. Two particular examples illustrate how misleading interpretations can be avoided by the combined use of these two techniques.
Potassium on the fracture surface of tungsten wires studied by AES
Authors: Menyhárd M. 
Published: December 2004

AbstractIndustrial tungsten wires were fractured using Auger equipment. The concentration of potassium on the fracture surface of the variously heat‐treated wires was markedly different. The results can be explained assuming that the wires were fractured along the potassium second phases. The spectra, similar to those normally interpreted as indicative of monolayer potassium segregation on the fracture surfaces, are here interpreted as arising from diffusion across the surface after fracture from the potassium inclusions and not from a segregated layer.
Thermal oxidation of GaOx Ny‐covered GaAs surfaces
Authors: Shiota I. , Nishizawa J. 
Published: December 2004

AbstractThe thermal oxidation of GaO x N y‐ covered GaAs surfaces is investigated mainly by means of a combined Auger‐sputtering method. It is shown that an oxide layer is formed mainly at the interface between the GaO x N y film and the GaAs on thermal oxidation in O2 gas, but the formation of the interfacial oxide layer is successfully suppressed by oxidizing in an atmosphere of O2 gas diluted with an excess amount of NH3 gas. The effects of oxidation temperature and the oxygen content in the GaO x N y film are further discussed. The properties of the interfacial oxide layer are compared with those of the oxide formed on free GaAs surfaces. Corresponding electrical properties are also examined.
Composition–Depth profiling and interface analysis of surface coatings using ball cratering and the scanning auger microprobe
Authors: Walls J. M. , Hall D. D. , Sykes D. E. 
Published: December 2004

AbstractThe provision of accurate composition–depth profiles to depths > 1 μm is important in the characterization and investigation of thick films, surface coatings, surface treatments and many other technologically important applications. At present, such profiles are usually achieved by sequential ion bombardment and surface analysis and hence involve many difficulties in interpretation due to the non‐uniform erosion of surfaces under ion bombardment. In this paper a method of obtaining accurate depth profiles is described using a ball‐cratering device. The method employs a rotating ball to fashion a well‐defined spherical crater in the sample surface, the depth and width of which can be accurately controlled. The specimen is then cleaned in situ using a scanning ion beam for a short period and the composition–depth profile is obtained either by point‐by‐point analysis down the sloping sides of the crater wall or by using Auger line‐scan techniques across the crater. Coating–substrate interface analysis can also be obtained by sputter–depth profiling at a point on the coating close to the exposed substrate. The method is not only considerably faster than ion etching, but the resulting depth profile also has a well‐defined depth resolution. Composition–depth profiles through nitrocarburized mild steel surfaces and protective surface coatings are presented to illustrate the usefulness of the technique.
The composition of Cu/Al thin films deposited by isothermal evaporation
Authors: Janda M. , Stefan O. , Kubový A. , Šťulík D. 
Published: December 2004

AbstractThe preparation and characterization of thin Cu/Al films is described. The single source evaporation process is treated theoretically and the calculated composition profile for a film prepared by evaporation of 5 wt% Al alloy is compared with the experimental data.
Problems of quantitative secondary ion microanalysis (SIMA) of low alloy steels
Authors: Illgen L. , Mai H. , Seidenkranz U. , Voigtmann R. 
Published: December 2004

AbstractThe applicablity of the National Bureau of Standards steel standards 461–468 and 662–664 for testing the CARISMACorrection program for quantitative secondary ion analyses, supplied by ARL, Sunland, California, USA.
program has been investigated. Measurement of the secondary ion intensity of a number of alloying elements using 16O primary ions of 20 keV kinetic energy and a primary ion beam 130 µm in diameter gave results of good reproducibility for repeated samplings of the same specimen (Srel always <0.2), thus indicating a tolerable sampling error. But for some of the elements measured a bad correlation between the secondary ion intensity and the elemental concentration of different standard samples has been found. Carbon (an element of great importance for the properties of steels and of major influence on the outcome of CARISMA calculations) showed the most arbitrary behaviour in this sense. Detailed investigations of the microstructure and microcomposition of the standard samples by metallography, texture analysis, EPMA with X‐rays and backscattered electrons, and particularly by SIMA, showed that (a) the carbon secondary ion intensity is correlated to the sum of the Ti, Zr, Nb and Ta concentrations in the samples, and (b) the microvolumes of enhanced carbon secondary ion emission are mainly mixed carbides or carbonitrides of Ti, Zr, Nb and Ta.