bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal Decomposition of Energetic Materials XVIII. Bis (cyanomethyl)nitramine and Bis(cyanoethyl)nitramine
Authors: Oyumi Y. , Rheingold A. L. , Brill T. B.
Published: May 2005

The crystal structures of two potentially useful cyanonitramines are reported. Bis(cyanomethyl)nitramine (BCMN), (NCCH2)2NNO2: monoclinic, C2, a = 10.247(1), b = 7.771(1), c = 12.230(2) [Å], β = 107.45 (2)°, Z = 6, Dcalc = 1.502 g.cm−3, RF = 2.8%, RwF = 3.1%. A syn (C2) and anti (Cs) isomers of BCMN crystallize together in a 2:1 ratio in the unit cell. Bis(cyanoethyl)nitramine (BCEN), (NCCH2CH2)NNO2: monoclinic, P21/c, a = 7.512(2), b = 10.840(3), c = 10.181(3) [Å], β = 97.39(2)°, Z = 4, Dcale = 1.357 g.cm−3, RF = 4.6%, RwF = 4.7%. Only one conformation of the BCEN molecule having no symmetry is present in the unit cell. The IR spectrum shows that BCEN forms an amorphous phase when the melt is cooled or when an acetone or acetonitrile solution is rapidly evaporated. The amorphous phase slowly crystallizes at room temperature. High‐rate thermolysis of BCMN liberates NO2 as the predominant initial product. This difference is qualitatively predictable on the basis of the variation in the N‐N bond distance in these two compounds.
Ballistic Modification of Composite Modified Double‐Base Propellants containing ammonium perchlorate
Authors: Raman K. V. , Singh Haridwar , Rao K. R. K.
Published: May 2005

The effect of certain lead and copper salts of organic acids and metallic oxides was studied on the burning rates and heat of explosion of CMDB propellants containing AP. Among lead and copper salts, basic lead salicylate gave increased burning rates, whereas lead methylene disalicylate and basic copper salicylate did not produce catalytic effect. In the case of metallic oxides, ferric oxide and cobalt oxide gave better catalytic activity than copper and chromium oxides. On crosslinking of nitrocellulose with an isocyanate, catalytic activity of ballistic modifiers was reduced. Burning rates obtained in a rocket motor (2‐kg propellant) were higher by about 15%‐20% than by strand burner (Crawford Bomb) method.
Combustion Process of Mg/TF Pyrotechnics
Authors: Kubota N. , Serizawa C.
Published: May 2005

The combustion process of pyrotechnics was studied in order to obtain informations of the rate control parameters of burning rate. The pyrotechnics tested was made of Mg (magnesium) and TF (polyfluoroethylene). The burning rate measurements revealed that the burning rate of the Mg/TF propellants (pellet in shape) increases with increasing the weight fraction (ξ) of Mg in the range of ξ > 0.33. Though the adiabatic flame temperature is the maximum at ξ = 0.33, the burning rate increases with decreasing the flame temperature. The total burning surface area of the Mg particles mixed with in the unit mass of propellant plays an important role on the oxidation process in the gas phase just above the propellant burning surface. The heat flux feedback from the gas phase to the propellant burning surface increases with increasing ξ. Therefore, the burning rate increases as ξ increases.
Determination of Derivatives of Diphenylamine in Australian Gun Propellants by high performance liquid chromatography
Authors: Curtis N. J. , Rogasch P. E.
Published: May 2005

A new high performance liquid chromatography (HPLC) method has been developed for the quantitative analysis of diphenylamine and its N‐nitroso‐ and C‐nitro derivatives found in single‐base gun propellants. Of the potential derivatives, only 2‐ and 4‐nitrodiphenylamine, 2,2′‐, 2,4′‐ and 4,4′‐dinitrodiphenylamine, 2,2′4‐ and 2,4,4′‐trinitrodiphenylamine. 2,2′4′4′‐tetranitrodiphenylamine, N‐nitrosodiphenylamine and 4‐nitro‐N‐nitrosodiphenylamine were found in major amounts. Minor derivatives noted were: 2,4‐dinitrodiphenylamine, 2‐nitro‐N‐nitrosodiphenylamine, 2,4′‐ and 4,4′‐dinitro‐N‐nitrosodiphenylamine. Other derivatives were looked for but not found. This HPLC method can be used to quantify all the major derivatives in a single chromatogram and importantly, can be used even in the presence of propellant additives dinitrotoluene, di(ethylhexyl) phthalate and dibutyl phthalate. This procedure provides the most effective analysis of stabilizer in single‐base propellants yet published. We have used this method to study the derivatisation of diphenylamine as a function of aging in Australian single‐base gun propellants.
Temperature sensitivity of Burning Rate of Ammonium Perchlorate Propellants
Authors: Kubota N. , Miyazaki S.
Published: May 2005

The temperature sensitivity of burning rate of ammonium perchlorate (AP) composite propellants was studied as a function of AP particle size and a burning rate catalyst. A simplified temperature sensitivity model was presented in order to discriminate the effect of the gas phase and solid phase reactions on the initial propellant temperature (T0). The temperature sensitivity was decreased by the addition of small sized AP particles and/or 2,2‐bis(ethylferrocenyl)propane (BEFP). This is caused by the insensitive burning surface temperature to T0. Thus, the gas phase reaction rate becomes little dependent on T0, and the temperature sensitivity decreases.
The properties of 1,3,3,5,7,7‐hexanitro‐1,5‐diazacyclooctane (HCO) and its application in propellants
Authors: Li‐Hua Xu , Ming‐xuan Wang , En‐pu Wang , Hui‐min Tan , Bo‐ren Chen
Published: May 2005

The properties of HCO and its application as a monopropellant were described. In comparison with HMX, it is also a high energetic explosive with high thermostability and can be used as an oxidizer in solid rocket propellants.

Theoretical specific impulse of HCO‐double base propellant systems were calculated and the burning rates and thermostability of propellant were experimentally determined. Propellants were prepared with a spray‐casting process. As an oxidizer in solid rocket propellant, HCO shows better characteristics under certain aspects compared with HMX.
Melt Phase Decomposition of RDX and Two Nitrosamine Derivatives
Authors: Oyumi Y.
Published: May 2005

Thermal decomposition of hexahydro‐1,3,5‐trinitroso‐s‐triazine (TRDX), C3H6N3(NO)3, and hexahydro‐1,3‐dinitro‐5‐nitroso‐s‐triazine (MRDX), C3H6N3(NO2)2(NO), was studied by DTA and TGA in argon atmosphere, which was showing overall first‐order kinetics. The results are compared with those for RDX in order to determine the effect of replacing > NNO2 group with > NNO. The decomposition of the admixture of RDX/TRDX (50/50 by weight) was also tested. The kinetic parameters calculated are: for RDX, ln k = 43.1–47,900/RT, for MRDX ln k = 34.3–37,200/RT, for TRDX ln k = 29. 4–30,500/RT, while for the RDX/TRDX admixture, ln k = 37.0–39,700/RT, where k is in s−1. The melt phase decomposition products of RDX, MRDX, and TRDX condensed on a NaCl plate which was placed 2 cm above the sample cell were almost exactly the same in IR measurements. RDX is soluble in liquefied TRDX and the decomposition of RDX is accelerated by its liquefaction.
Selection of an igniter system for magnesium‐based solid fuel rich propellant
Authors: Singh Harihar , Somayajulu M. R. , Bhaskar Rao R.
Published: May 2005

Suitability of a number of metal based igniter compositions have been studied for magnesium based fuel rich propellant. Igniter compositions have been tested in closed vessel for evaluation of ignition pressure output and impetus. Heat energy values were determined calorimetrically in a closed bomb. Vented vessel study was carried out in a test motor for assessing relative behaviour and to select a suitable composition. Compositions containing magnesium powder and potassium nitrate were found to give satisfactory ignition to the propellant.
Optimization of Spark and ESD Propellant Sensitivity Tests. A review
Authors: Mellor M. , Stoops David R. , Rudy Tom P. , Hermsen Robert W.
Published: May 2005

All cured propellants can pass small‐scale spark sensitivity tests, yet some, generally involving larger propellant samples, are electrostatic discharge (ESD) sensitive. These tests fail to rank propellants because the test methods themselves are not optimized and frequently use instrumentation which does not indicate the energy transferred to the sample.

For spark ignition of premixed combustible gases or fuel sprays in air, minimum energies are measured and considered thermochemical properties for a given fuel/air ratio, initial temperature and pressure, and for a spray, a given droplet size distribution. Obtaining such data requires monitoring the total energy discharged across the gap during the spark and parametric studies where gap length and spark duration are varied systematically to establish the true minimum (essential to hazard/risk analysis). Electrode geometry and tip design, as well as electrode material, are other important considerations.

Present spark and ESD sensitivity tests used for solid propellants are reviewed in the context of methods more likely to provide meaningful initiation thresholds.
Spectrophotometric Determination of Lead in some propellants
Authors: Zaki M. Tarek M. , Bassioni H. H. , Sedra M. N. R. , Attiya S. M.
Published: May 2005

A new sensitive method has been proposed for the determination of lead in some single‐ and double‐base propellants. The method is based on the color reaction of lead(II) with hematoxylin in presence of the cationic surfactant cetyltrimethylammonium bromide. At pH 8.0, the formed ternary system possesses an absorption maximum at 605 nm with a molar absorptivity of 5.5 × 104 l · mol−1 · cm−1. The system adheres to Beer's law up to 1.78 ppm of lead, and the sensitivity index is 0.0039 μg · cm 2. The susceptibility of interference of common ions is studied and some masking agent solutions are recommended to improve the selectivity of the method. The proposed method shows good agreement with the results obtained by atomic absorption spectrometry. An average recovery of 99.3% with a standard deviation not exceeding 1.7% is observed.
Synthesis of novel energetic compounds. 8. Electrosynthesis of azidodinitromethyl compounds
Authors: Weber James F. , Frankel Milton B.
Published: May 2005

Azidodinitromethyl compounds represent a new highly energetic class of propellant ingredients. Preparation of these materials was accomplished by means of electroxidative coupling of azide ions to dinitromethyl carbanions. Thus, anodic coupling of sodium azide with ethyl 4,4‐dinitrobutyrate produced ethyl 4‐azido‐4,4‐dinitrobutyrate. Similarly, 4‐azido‐4,4‐dinitrobutyl acetate was prepared from 4,4‐dinitrobutyl acetate and converted by way of the corresponding alcohol to the nitrate ester, 4‐azido‐4,4‐dinitrobutyl nitrate.
Linking experimental and theoretical results on the Deflagration to Detonation Transition
Authors: Verbeek Ries , van der Steen Albert
Published: May 2005

The results of a DDT tube test are compared with the outcome of a numerical model. The interaction between the two research methods leads to a better understanding of the DDT phenomenon than each method separately. For the situation tested the way of ignition and the particle diameter appeared to be important factors for the DDT process.
Performance of High Explosives in Underwater Applications. Part 1: CHNO explosives
Authors: Strømsøe E. , Eriksen S. W.
Published: May 2005

The change in postdetonation free energy, rather than the often used change in detonation enthalpy, is suggested as a measure of the underwater performance of high explosives. Results of a correlation analysis of data from 11 explosives are presented. It is suggested that the detonation pressure is also a significant factor for the energy available for mechanical work, but this can not be verified by the present data. However, in the partition of energy between shock wave and bubble the detonation pressure is the dominant factor.
Performance of high explosives in underwater applications. Part 2: Aluminized explosives
Authors: StrøMsøE E. , Eriksen S. W.
Published: May 2005

The change in postdetonation free energy has been used for assessment of the sum of shock and bubble energies of aluminized explosives in underwater applications. As has been suggested for CHNO explosives the detonation pressure also in this case seems to be a significant factor. For compositions with a high Al content it is probable that additional energy becomes available from reaction of Al with water in the surrounding medium.
Correlation between Gas Evolution under Vacuum or Pressure and Stability of Single‐Base Propellants
Authors: SyryczyńSki Piotr , Szmajda Jerzy
Published: May 2005

The processes of the gas liberation during heating single‐base propellants in vacuum or underatmospheric pressure has been studied. The results for several samples with various size of grains, water content and methods of production were compared. The results of the tests under vacuum cannot be the strict and simple measure of the stability of propellants. It is not clear whether the increase of pressure is due to the breakdown of RO‐NO2 bonds or is noly due to the evaporation of the derivatives of primary stabilizer. The amount of gas evolved depends on the size of grains, type of stabilizer, various additives etc.

There are no strict boundaries between stable and unstable propellants when their decomposition rate under atmospheric pressure is measured. This method of determining the stability of single‐base propellants is useless for old samples made by unknown technology.
Effects of Partially Confined Explosion on Jet Penetration
Authors: Yadav H. S. , Bohra B. M. , Sundaram S. G. , Kulkarni M. W.
Published: May 2005

Interaction of a metal‐explosive assembly with a normally‐incident shaped chare jet has been investigated with radiographic and oscillographic technique. Some of the significant effects associated with this interaction like detonation of explosive by impact of jet, expansion of covering metal plates, disturbance in coherence and reduction in penetration of the jet have been observed. It is found that the jet penetration in stack of mild steel plates is reduced to 30% of its blank penetration. The disturbance in the jet commences 12.3 μs after initiation of explosive and it remains for about 25 μs in the present set up.
Study of explosive and shock parameters for Compaction of Powders
Authors: Yadav H. S. , Patil B. T. , Haldar G.
Published: May 2005

Compaction of aluminium, iron and tungsten powders of particle size 300 BSS has been studied by axisymmetrical geometry. Optimum explosive to powder mass ratio (E/M) to attain maximum density of compact has been determined for different tube diameters in each case. It has been observed that E/M ratio for smaller diameter tube is greater than that of bigger diameter tubes. Explosive and shock wave parameters like velocity of detonation and angle of conical shock wave have also been measured with sulphur coated pin oscillographic technique.
Spectroscopic Studies on Electron Donor‐Acceptor Complex between n,2,4,6‐tetranitro‐N‐methylaniline and ethylenediamine
Authors: Raha K. , Makashir P. S. , Kurian E. M.
Published: May 2005

Spectroscopic studies indicate that N,2,4,6‐tetranitro‐N‐methylaniline (tetryl) forms two charges transfer (CT) complexes with ethylenediamine (EDA) and these complexes show absorption maxima at 440 nm and 340 nm respectively. Both the complexes have 1:1 ratio of donor to acceptor. The formation constant and molar extinction coefficient for the complexes have been determined in acetonitrile as well as in ethanol and methanol to evaluate the effect of polarity. The initial complex (λmax at 440 nm) undergoes transformation to a product complex (λmax at 340 nm) when the EDA concentration is lowered. The product complex has been isolated and characterized by IR, UV spectroscopy, thermal analysis and X‐ray diffraction (XRD). The transformation of the initially formed CT complex to the product complex in solution has been found to obey first order kinetics. The formation of CT complex of tetryl with EDA has been succesfully used to develop a spectrophotometric method for the quantitative determination of tetryl.
Energetics of AMMO
Authors: Bazaki Hakobu , Kubota Naminosuke
Published: May 2005

The thermal decomposition process and combustion wave structure of azide polymer were studied to determine the parameters which control the burning rate. The azide polymer studied was 3‐azidomethyl‐3‐methyl oxetane (AMMO) which contains energetic –N3 groups. From the experiments, it was found that the thermal decomposition process of AMMO consists of a two‐stage weight loss process: the first‐stage corresponds to an exothermic reaction which is caused by the scission of N‐N2 bond, and the second‐stage corresponds to the decomposition of the remaining fragments. The burning rate of AMMO is approximately 50% of the burning rate of GAP propellant and is as high as that of conventional double base propellant. The heat feedback from gas phase to the burning surface increase with increasing pressure. The burning surface temperature and the heat of reaction at the surface decrease with increasing pressure.
Thermal Decomposition of Energetic Materials 56. On the fast thermolysis mechanism of ammonium nitrate and its mixtures with mangnesium and carbon
Authors: Patil Dilip G. , Jain Sampat R. , Brill Thomas B.
Published: May 2005

Fast thermolysis studies of ammonium nitrate (AN) and its mixtures with magnesium and activated charcoal have been carried out by the Fourier transform infrared spectroscopy/temperature profiling technique. When subjected to rapid heating (ca. 80°C/s), AN Sublimes/decomposes around 300°. Sublimation dominates at ambient pressures. The IR‐active products of decomposition are NH3, NO2, N2O and H2O. Reaction schemes accounting for the products are proposed which involve proton transfer leading to NH3 by the decomposition products of HNO3. The decomposition of AN is significantly enhanced when AN is mixed with magnesium powder or charcoal, and occurs at as low a temperature as 135°C. Whereas NH3 is the major product of decomposition of ANMg mixtures, no NH3 is observed from ANC mixtures. The results are explained by the reaction of HNO3 and NH3 with Mg or C.
Assessment scheme for the chemical compatibility of materials with cast double base propellants
Authors: Keeton G. M. , Facer D.
Published: May 2005

The scheme for the compatibility assessment of materials with cast double base propellants as operated at Royal Ordnance Summerfield is described. Central to the scheme is the recognition that evaluation of the compatibility of materials must consider two areas of safety. These are on‐site process safety requirements, and rocket motor service life which includes safe chemicalstability and the long term functioning and reliability of a store. To rationalize testing, a system of compatibility testing to defined categories classified by the application and usage of a material is followed.
Thermal Decomposition of Azide Polymers
Authors: Oyumi Yoshio
Published: May 2005

Thermal decomposition of polyglycidyl azide (GAP) and bis(azidomethyl)oxetane/tetrahydrofuran copolymer (BAMO/THF) was studied by TGA and DSC in helium atmosphere, which was showing overall first‐order kinetics. The additional azide groups at terminal position in the molecular structure decomposed independently and increased the rate of decomposition. However, the decomposition kinetics was less affected by the additional azide groups in the main chain. The decomposition properties of aged polymer Samples were the same as those of untreated ones. Catocene significantly altered the decomposition temperatures of GAP and BAMO/THF. The speak temperature of DSC thermogram changed from 533 K to 494 K in GAP and from 535 K to 498 K in BAMO/THF. Like UV treatment, BAMO/THF with catocene was thermally cross‐linked during the aging at 343 K. Although BAMO/THF with catocene produced rubbery solids from the initial viscous liquids, there was no significant difference between the rate of decomposition of treated sample and that of untreated one.
Studies on the critical temperature of thermal explosion for 3‐Nitro‐1,2,4‐triazol‐5‐one (NTO) and its salts
Authors: Yi Xie , Rongzu Hu , Chaoqing Yang , Guofu Feng , Jihua Zhou
Published: May 2005

The critical temperature of thermal explosion for 3‐nitro‐1,2,4‐triazol‐5‐one (NTO) and its ethylenediammonium salt (ENTO), potassium salt (KNTO), copper salt (CuNTO) and lead salt (PbNTO) were obtained using the stationary theory of thermal explosion, the calculation formula of estimating the critical temperature of thermal explosion under non‐isothermal DSC condition, and the determination method for the critical temperature of thermal explosion of small‐scale solid explosive and its data treatment method. The results of the four methods are agreeable to each other, whose differences are within 5%. The results indicate that the heat‐resistance ability of NTO and its salts and of the common explosives, cyclotetramethylenetetranitramine (HMX), cyclotrimethylenetrinitramine (RDX), pentaerythritoltetranitrate (PETN) and tetryl decreases in the order HMX > NTO > ENTO > KNTO > RDX > PETN > tetryl > PbNTO > CuNTO.
Stability Studies on Pentaerythritol Tetranitrate
Authors: Om Reddy G. , Srinivasa Rao A.
Published: May 2005

Tyhe influences of acidity and dipentaerythritol hexanitrate (DiPEHN) on the thermal sensitivity of pentaerythritol tetranitrate (PETN) was studied using differential scanning calorimetry (DSC). Decomposition kinetics of PETN with or without DiPEHN, acidic PETN and DiPEHN were also studied by SC to evaluate Arrhenius parameters. The presence of sulphuric acid impurity decreased the thermal stability as well as the activation energy, whereas the nitric acid influence was negligible. Thermal stability of PETN was not affected by the presence of DiPEHN. DiPEHN showed better thermal stability and higher decomposition energy compared to PETN.
Experimental Study of Shaped Charges with built‐in asymmetries
Authors: Brown John , Softley I. D. , Edwards P.
Published: May 2005

Shaped charges have been manufactured and fired with built‐in asymmetries, some with the initiation system placed off‐centre, one with the casing around the explosive being of uneven thickness. The jets from these charges were radiographed, and the lateral and axial velocities of the particles were measured. The collapse process appears to be much more sensitive to the effects of decentration of the initiation point than to asymmetrical confinement. For small angles between the detonation wave and the axis of the liner, jet elements depart from the collapse zone at an angle similar to, and in the opposite sense from, the angle between the wave and the relevant part of the liner.

The aim of this paper is to provide workers in the fields of the design, manufacture, and modelling of shaped charges with a database of quantitative information concerning the effects on the off‐axis motions of jet particles which occur if the charge and its initiation system lack perfect rotational symmetry. Pioneering work on this subject was done by Professor (then Doctor) Manfred Held in the early days of his work with Thomanek at Messerschmitt‐Bölkow‐Blohm. We offer some quantitative results to build on that pioneering work.
Electric spark and esd sensitivity of reactive solids (primary or secondary explosive, propellant, pyrotechnics) part one: Experimental results and reflection factors for sensitivity test optimization
Authors: Roux Michel , Auzanneau Max , Brassy Claude
Published: May 2005

An experimental study shows that spark energy transfer mechanisms are different for the explosive alone (HMX) and for the explosive containing 1% of graphite. This study is completed by literature data and underlines the need for parametric studies by systematically varying the electrodes gap as well as the spark duration to determine the true minimum value of the ignition energy. Grain size and shape are very important factors. The influence of the electrode shape is also discussed, as well as the environmental conditions. These data allow us to determine the conditions for testing the electric spark sensitivity of solids. The tests are then performed at a small scale.

Moreover, for ionic solids or substances made of an electrically insulating matrix containing conductive inclusions, particular phenomena appear when they are submitted to electric fields for a certain time. These phenomena justify the development of specific tests to determine the capacitive discharge sensitivity.
Volatility of NENA and Other Energetic Plasticizers determined by thermogravimetric analysis
Authors: Cartwright R. V.
Published: May 2005

Thermogravimetric analysis (TGA) at constant temperature was used to measure weight loss of plasticized nitrocellulose (NC) propellants due to vaporization of plasticizer. Plasticizers consisted of three 2‐nitroxyethylnitramine (NENA) compounds, diethylene glycol dinitrate (DEGDN), and nitroglycerin (NG). Initial concentration of plasticizer and degree of nitration of NC were also varied. Each propellant was tested at three temperatures. Plasticizer diffusivities (D) and their activation energies were calculated. Observed trends were generally consistent with calculated plasticizer solubility parameters, expected increases in molecular mobility for more highly plasticized materials, and the more polar and more disordered structure of NC with a lower degree of nitration. Some unexpected effects could be explained by changes in entropy of activation due to variation in plasticizer or NC structure. In general, the NENA plasticizers had lower vaporization rates than DEGDN or NG, suggesting that plasticizer losses during manufacturing or storage of practical formulations should not be a problem.
Thermal Decomposition of HMX and Mixtures
Authors: Hussain G. , Rees G. J.
Published: May 2005

Thermal decomposition of pure HMX shows DSC endothermic peaks at 210°C from β to γ phase transformation and at 285°C from the HMX melting followed by an instantaneous exothermic decomposition leading to a strong peak at 290°C and a very strong DTG peak at 325°C with a mass loss of 95%. However, the GS‐2 mixture shows two DSC exothermic peaks at 225°C and 270°C assigned to nitroguanidine etc. and HMX decomposition. Addition of NH4ClO4 to HMX causes the decomposition to take place before melting and decomposition peak is lowered to 230°C. However in the case of GS‐2, a strong effect was observed and the amount of the mixture was to be decreased to obtain a reasonable DSC curve. This shows that the addition of NH4CIO4 to HMX increases the decomposition of HMX, however this effect is more pronounced in GS‐2 mixture. Even the minimum concentration of NH4CIO4 tested (10%) shows strong effect.

The addition of NH4NO3 to HMX and GS‐2 shows DSC exothermic decomposition peaks at 272°C and 245°C, showing a contribution from NH4NO3 decomposes near to the decomposition of HMX, it does not show a strong effect on the decomposition of HMX/GS‐2 as compared to NH4ClO4. Addition of KClO4, NaClO4 and KNO3 don't show any effect in these thermoanalytical studies.
Nitroureas II. Synthesis of Bicyclic Mono‐ and Dinitrourea Compounds
Authors: Pagoria Philip F. , Mitchell Alexander R. , Jessop Edward S.
Published: May 2005

We report the synthesis and characterization of several bicyclic mono‐ and dinitrourea compounds as energetic materials and discuss their use as precursors to other energetic compounds. The new nitrolyzing reagent, trifluoromethanesulfonic acid anhydride/20% N2O5/nitric acid, will also be described.
On the validity of the thermal explosion model in shock wave initiated nitromethane
Authors: Pujols Henri‐Christian , Pouligny Brigitte
Published: May 2005

By means of Perot Fabry Velocimetry (PFV) we recorded material velocities generated by an intense shock wave (P > 70 kbar) in pure nitromethane. Our experiments show that nitromethane does not behave according to the Campbell‐Travis model for detonation in liquid explosives. We do not find any evidence for a so‐called superdetonation, which would start behind and overtake the pressure shock wave. Our recordings of material velocities show a behavior of the liquid explosive very similar to that of solid polycrystalline explosives and are compatible with the heterogeneous decomposition scheme.
Behavior of an Inclined Jet after Penetration in a Contact Surface
Authors: Guanren Zhang
Published: May 2005

Experimental facts show that when the direction of a metallic jet is inclined to the target surface, the penetration length may be decreased enormously. In this paper, the author proves this phenomena by a theoretical analysis. The conclusion could also be used in the respect of anti‐hollow charge warheads.
Estimation of thermodynamic stability conditions and perspectives for synthesis of covalent carbon nitride
Authors: Odintsov Victor V. , Pepekin Vitaly I.
Published: May 2005

The present work is devoted to the determination of conditions of thermodynamic stability of carbon nitride having structure of β‐C3N4. The thermodynamic functions of crystalline covalent carbon nitride required for thermodynamic reckoning of parameters of formation of carbon nitride were determined on the base of the Debye theory with the characteristic temperature varied in the range from 1000 K to 2500 K. The formation enthalpy of carbon nitride was estimated on the base of the energy of atomization and formation enthalpy of a mixture of atomized carbon and nitrogen. The resulted quantity of the standard formation enthalpy of covalent carbon nitride at 298.15 K made up 4.47 kcal/mol. Thermodynamic computations were accomplished with the use of the Automated System of Thermodynamic Reckonings and Algorithms ASTRAL. Behavior of the gaseous phase of a chemical system was described by the BKW‐RR equation of state. Carbon nitride was considered to be incompressible. The region of thermodynamic stability of covalent carbon nitride is computed. It is shown that in contrast to the carbon condensation into graphite the pressure of condensation of β‐C3N4 when adding other chemical elements to a thermodynamic system can not only increase but decrease as well. Consideration of detonation and explosion processes in high explosives shows a way for practical synthesis of covalent carbon nitride.
Phase State of Nitrocelluloses Plasticized with Trinitroglycerin
Authors: Lotmentsev Yu. M. , Pleshakov D. V.
Published: May 2005

This work aims at an investigation of the thermodynamical compatibility of nitrocellulose with nitroglycerin. The study resulted in the construction of the phase diagram for the nitrocelluloses‐trinitroglycerin system. The diagram can be used in predicting the thermodynamical stability and phase constitution of the composition prepared on the basis of these components.
Stationary phases. Part 39(1): Trace analysis of RDX in HMX on a novel copoly(vinylthiazole‐vinylimidazole) stationary phase by HPLC
Authors: Shieh Kuan‐Jiunn , Lee Sheau‐Long , Chang Chenq‐Shyong , Wen Cheng‐Hau , Den Tschau‐Gan
Published: May 2005

A method for the HPLC analysis of RDX and HMX on a novel copoly(vinylthiazole‐vinylimidazole) stationary phase [P(Th‐Im) phase] is described. Special elution order of RDX and HMX on this phase using methanol/water (60/40∼90/10) as mobile phase is HMX > RDX, which is quite different from those on a commercial RP‐18 phase. The chromatographic selectivities (α‐values) between RDX and HMX are 2.40∼2.55. This advantage can be used to identify the limited impurity of ca. 1 ppm RDX in HMX during the manufacture of HMX.
Ignition of pyrotechnic mixture by means of a laser diode. Part II: Experimental study
Authors: Roux M. , Gillard Ph.
Published: May 2005

An experimental device using a laser diode is described. The laser diode is coupled with a 100 μm diameter optical fiber. Lasering times are about one ms and the energy of the pulse ranges from 0.5 mJ to 5 mJ. Output power provided by optical fiber is about 0.5 W and the wavelength of radiation is 820 nm. Before each shot the pulse energy is measured by means of a joule meter. It allows a very accurate determination of the amount of energy transferred to the solid explosive. A small reactor containing about 40 mg of explosive is used. It allows to initiate combustion with a direct contact between the output of an optical fiber and the solid explosive. Three pyrotechnic compounds were tested and tests have shown that it is possible to ignite Zr/KClO4 and Zr/PbCrO4 mixtures. Experimental results are discussed and compared with numerical simulations presented in Part I.
Shaped Charge Jet Tail Velocity
Authors: Me‐Bar Yoav , Partom Yehuda
Published: May 2005

The impact of a shaped charge jet, created by a stationary charge onto a moving target, creates an elongated cut on the target face. The length of the cut, together with additional data about the charge and target configuration, enables the calculation of the jet tail velocity. It was found that this velocity increases with the stand‐off distance between the charge and the target. A possible cause for this acceleration is that the jet material is under tension due to the velocity gradient along it and the stress throughout it equals the dynamic flow stress of the material. This stress pulls on the jet material towards the center of gravity and tends to reduce the velocity gradient, i.e. decelerate the tip and accelerate the tail. 1D simulations show that this mechanism results in a constant acceleration of the tail, and that the acceleration depends on the flow stress of the jet material, hence on its temperature. Based on the experimental evidence and on the simulations, it is postulated that in addition to the velocity gradient along the jet, there are temperature and strength gradients along it, as well.
Ribosome‐inhibiting proteins, retroviral reverse transcriptases, and RNase H share common structural elements
Authors: Ready Michael P. , Katzin Betsy J. , Robertus Jon D.
Published: May 2005

Plant ribosome‐inhibiting proteins are shown to be homologous at the domain level to RNase H form Escherichia coli and to two regions of the pol gene product of retroviral reverse transcriptases. One of these regions carries the viral integrase or int function, while the other has previously been suggested to contain the viral RNase H exo activity. Several residues conserved among the ribosome inhibitors, E. coli RNase H, and the integrase proteins are seen to occupy a prominent cleft in the tertiary structure of the ribosome inhibitor ricin, suggesting roles in binding or catalysis. It is likely that these homologous sequences represent modern derivatives of an ancient protein‐folding unit capable of nucleic acid binding and modification which has been incorporated into a variety of enzyme functions.
The three‐dimensional structure of recombinant bovine chymosin at 2.3 Å resolution
Authors: Gilliland Gary L. , Winborne Evon L. , Nachman Joseph , Wlodawer Alexander
Published: May 2005

The crystal structure of recombinant bovine chymosin (EC 3.4.23.4; renin), which was cloned and expressed in Escherichia coli, has been determined using X‐ray data extending to 2.3 Å resolution. The crystals of the enzyme used in this study belong to the space group I222 with unit cell dimensions a = 72.7 Å, b = 80.3 Å, and c = 114.8 Å. The structure was solved by the molecular replacement method and was refined by a restrained least‐squares procedure. The crystallographic R factor is 0.165 and the deviation of bond distances from ideality is 0.020 Å. The resulting model includes all 323 amino acid residues, as well as 297 water molecules. The enzyme has an irregular shape with approximate maximum dimensions of 40 × 50 × 65 Å. The secondary structure consists primarily of parallel and antiparallel β‐strands with a few short α‐helices. The enzyme can be subdivided into N‐ and C‐ terminal domains which are separated by a deep cleft containing the active aspartate residues Asp‐34 and Asp‐216. The amino acid residues and waters at the active site form an extensive hydrogen‐bonded network which maintains the pseudo 2‐fold symmetry of the entire structure. A comparison of recombinant chymosin with other acid proteinases reveals the high degree of structural similarity with other members of this family of proteins as well as the subtle differences which make chymosin unique. In particular, Tyr‐77 of the flap region of chymosin does not hydrogen bond to Trp‐42 but protrudes out in the P1 pocket forming hydrophobic interactions with Phe‐119 and Leu‐32. This may have important implications concerning the mechanism of substrate binding and substrate specificity.
Crystal structure of a protein‐toxin α1‐purothionin at 2.5Å and a comparison with predicted models
Authors: Teeter Martha M. , Ma Xing‐Qi , Rao Usha , Whitlow Marc
Published: May 2005

α1‐Purothionin (α1‐P), a wheatgerm protein and lytic toxin, has a secondary and tertiary structure similar to that of crambin as revealed by CD and NMR studies. α1‐P crystallizes in the tetragonal space group I422 with unit cell dimensions: a = b = 53.59 and c = 69.79 Å. X‐ray diffraction data have been measured to 2.5 Å Bragg spacing. The crystal structure has been determined by molecular replacement methods, using an energy‐minimized α1‐P model structure derived from crambin (Whitlow and Teeter: Journal of Biomolecular Structure and Dynamics 2:831–848, 1985, Journal of the American Chemical Society 108:7163–7172, 1986). The energy‐minimized model gives a slightly cleaner rotation solution and better refinement against the x‐ray data than do the crambin or unminimized α1‐P structures. The final crystallographic residual with the data in the 10–2.5 Å resolution range is 0.216. The refined α1‐P structure has a backbone rms difference of 0.74 Å from crambin and 0.55 Å from the energy‐minimized α1‐P model. A low resolution NMR model of α1‐P calculated from metric matrix distance geometry and restrained molecular dynamics differs from crambin's backbone by 2.3 Å rms deviation (Clore et al.: EMBO Journal 5:2729–2735, 1986). Backbone dihedral angles for our predicted model differ from the refined α1‐P structure in only one region (at a turn where there is a deletion relative to crambin). The NMR model had differences in four regions.
Analysis of protein sheet topologies by graph theoretical methods
Authors: Koch Ina , Kaden Frieder , Selbig Joachim
Published: May 2005

In order to find rules for the secondary structure prediction of proteins which describe the (sequentially) long‐range interactions in sheet structures methods of applied graph theory were used. The so called β graph which describes the sheet topology was defined for every protein in the Brookhaven Data Bank containing β sheets. The resemblance of proteins at that topological level is discussed, and four notations and graphic representations of sheets which describe the sequential and topological neighborhoods of the strands were derived. This description level supports the usage of data structures which allow the implementation of efficient algorithms for the analysis and comparison of β structures in proteins. A computer program for the representation and retrieval of bibliographic data and β sheet structures was implemented. Some examples for substructure search illustrate the usefulness of the program. Two graphic catalogues were compiled: one contains all β graphs of PDB proteins and the other all occurring different greek key descriptions.
Primary mutations in calmodulin prevent activation of the Ca+ +‐dependent Na+ channel in Paramecium
Authors: Ling Kit‐Yin , Preston Robin R. , Burns Robert , Kink John A. , Saimi Yoshiro , Kung Ching
Published: May 2005

Paramecium tetraurelia behavioral mutant cam12 displays a “fast‐2” behavioral phenotype: it fails to respond to Na+ stimuli. Electrophysiologically, it lacks a Ca+ +‐dependent Na+ current. Genetics and DNA sequencing showed the primary defect of cam12 to be in the calmodulin gene (Kink et al., 1990). To correlate calmodulin structure and function in Paramecium, we elucidated the primary structure of cam12 calmodulin. Peptide sequencing confirmed the two point mutations predicted by the DNA sequence: a glycine‐to‐glutamate substitution at position 40 and an aspartate‐to‐asparagine substitution at position 50. Our results further showed that lysine 13 and lysine 115 were methylated normally in cam12. It is likely that the electrophysiological abnormalities of cam12 are a direct reflection of the amino‐acid substitutions, as opposed to improper posttranslational modification.
NMR study of the reconstitution of the β‐sheet of thioredoxin by fragment complementation
Authors: Tasayco María Luisa , Chao Kan
Published: May 2005

The study of complementary protein fragments is thought to be generally useful to identify early folding intermediates. A prerequisite for these studies is the reconstitution of the native‐like structure by fragment complementation. Structural analysis of the complementation of the domain‐sized proteolytic fragments of E. coli thioredoxin, using a combination of H‐exchange and 2D NMR experiments as a fingerprint technique, provide evidence for the extensive reconstitution of a native β‐sheet, with local conformational adjustments near the cleavage site. Remarkably, the antiparallel β‐strand between the fragments shows a native‐like protection of the amide protons to solvent exchange. Our results indicate that these fragments can be useful to study the early events in the still little understood formation of β‐sheets. © 1995 Wiley‐Liss, Inc.
Crystallization and preliminary crystallographic data for class I deoxyribose‐5‐phosphate aldolase fromEscherichia coli: An Application of Reverse Screening
Authors: Stura Enrico A. , Ghosh Sutapa , Garcia‐Junceda Eduardo , Chen Lihren , Wong Chi‐Huey , Wilson Ian A.
Published: May 2005

X‐ray quality crystals of class I deoxyribose‐5‐phosphate aldolase fromEscherichia colihave been obtained for the unliganded enzyme and in complex with its substrate, 2‐deoxyribose‐5‐phosphate. The enzyme catalyzes the reversible cleavage of 2‐deoxyribose‐5‐phosphate to acetaldehyde and D‐glyceraldehyde‐3‐phosphate. The unliganded and complex crystals are prismatic long rods and belong to the orthorhombic space groupP212121with cell dimensionsa= 183.1 Å,b= 61.4 Å,c= 49.3 Å anda= 179.2 Å,b= 60.5, Å,c= 49.1 Å, respectively. Two molecules in the asymmetric unit are related by a noncrystallo‐graphic 2‐fold axis. The crystals are stable in the X‐ray beam and diffract to at least 2.6 Å. A new method, reverse screening, designed to minimize protein utilization during the screening process was used to determine supersaturation and crystallization conditions. © 1995 Wiley‐Liss, Inc.
Characterization of the mycotoxin fumonishin B1: Comparison of thermospray, fast‐atom bombardment and electrospray mass spectrometry
Authors: Korfmacher W. A. , Chiarelli M. P. , Lay J. O. , Boloom J. , Holcomb M. , McManus K. T.
Published: May 2005

The utility of the thermospray mass Spectrometry (TSMS), fast‐atom bombarment mass spectrometry (FABMS), and elctropray mass spectrometry (ESMS) for the analysis of Fumonisin B1 is investigative. In Additional, the analysis of two stanards of Fumonisim B1 as well as an inculated corn culture extract that contained Fumonism B1 is reported. The result of these efforts show that ESMS, as Well as FABMS and a combination of FAB and tandem mass spectrometry (FABMS/MS), provide useful data for the characterization of Fumonisin B1. The detection limit was 50 pg for Fumonism B1 when analyzed by full scan FABMS, and 5 pg when analyzed by single‐reaction monitoring FABMS/MS.
Aromatic hydrocarbon derivatives of fullerences
Authors: Hoke Steven H. , Molstad Jay , Payne Gregory L. , Cotter R. J. , Kahr Bart , Ben‐Amotz Dor , Cooks R. Graham
Published: May 2005

The fullerences C60 and C70 form adducts with toluene, p‐xylene and other aromatic compounds when refluxed in these solvents in the presences of FeCl3. Benzene derivatives are produced only when bromine is also present. Mass spectra of the reaction mixtures indicate the presence of derivatives including 1:1 adducts, as well as products of multiple additions of the aromatic molecules and their dehydrogenation products. Tandem mass spectrometry provides evidence for CC bonds formation between the adducts and fullerences.
The use of electrospray ionization with Fourier transform ion cyclotron resonance mass spectrometry in the analysis of trace impurities in a drug substance
Authors: Haskins Neville J. , Eckers Christine , Organ Andrew J. , Dunk Michael F. , Winger Brian E.
Published: May 2005

The separation of trace impurities in cimetidine drug substance by high pressure liquid chromatography (HPLC) showed a series of minor components. These were analysed using an on‐line electrospray source connected to a Fourier transform ion cyclotron resonance (FT‐ICR) mass spectrometer. Working typically with a resolution of 10 000–20 000 accurate mass measurement of the components confirmed their empirical formulae to generally better than 5 ppm accuracy. This work shows that the combination of conventional analytical HPLC using 4.6 mm columns with a low flow rate electrospray source interfaced to an FT‐ICR mass spectrometer enables structural information to be obtained on low levels of low mass components.
Electron ionization mass spectrometry of some substituted, stereoisomeric, partly saturated 1,3‐ and 3,1‐benzoxazino‐1,3‐benzoxazines
Authors: Joutsiniemi Karoliina , Vainiotalo Pirjo , Pihlaja Kalevi , Lázár László , Fülöp Ferenc , Bernáth Gábor
Published: May 2005

The electron ionization mass spectra of five substituted, partly saturated 3,1‐benzoxazino‐1,3‐benzoxazines and four substituted 1,3‐benzoxazino‐1,3‐benzoxazines were measured and analysed. The fragmentation pathways were elucidated by metastable ion analysis and exact mass measurement. Although the principal fragmentations were similar for all these compounds, there was an important difference between the two groups as concerns the fragmentation routes. Both routes led to the same fragment ion, but in different ways depending on the ring structure. On the basis of the different fragmentation mechanisms, the 3,1‐benzoxazino‐1,3‐benzoxazines and the 1,3‐benzoxazino‐1,3‐benzoxazines can be distinguished mass spectrometrically. The saturation, the stereochemistry and the substituents all affected the fragmentations, mainly the peak intensities.
High resolution matrix‐assisted laser desorption/ionization time‐of‐flight analysis of single‐stranded DNA of 27 to 68 nucleotides in length
Authors: Christian Noah P. , Colby Steven M. , Giver Lori , Houston Chris T. , Arnold Randy J. , Ellington Andrew D. , Reiily James P.
Published: May 2005

Mass spectra of single‐stranded DNA oligonucleotides were acquired using matrix‐assisted laser desorption/ ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS). Resolution enhancement using space–velocity correlation focusing allows for facile observation of different oligomers, the direct observation of individual DNA–metal adducts, and investigation of counter ion structure.
The influence of X‐ray‐induced Auger electrons in quantitative electron‐induced Auger spectroscopy
Authors: Cazaux J. , Moutou S.
Published: May 2005

The X‐ray‐induced Auger electron intensities are often neglected in quantitative electron‐induced Auger electron spectroscopy. For the first time, analytical expressions are given for these relative intensities (induced by continuous or characteristic X‐rays). The influence of the operating voltage and the effects of the bulk and surface compositions are also discussed. Some numerical values show that at high operating voltages these intensities can reach several tens of percent of the Auger intensity directly created by the incident electron beam. Such contributions increase the apparent backscattering parameter r, therefore, they cannot be neglected when accurate quantitative analysis is required. Though such influences are troublesome for the analysis of small precipitates in scanning Auger electron microscopy, they can also give additional information on the bulk composition of a sample.