摘要:

AbstractThe thermal decomposition of six related nitraminotctrazoles and nitramino‐1, 2, 4‐triazoles at slow (5°C/min, DSC) and fast (⪈ 70°C/s, FTIR/temperature profiling) heating rates is described. The nitramine protion of the molecule appears to initiate the degradation in all cases except 5‐nitraminotetrazole (5‐NATZ) where the tetrazole ring is the trigger linkage. The crystal structures of DNTP and 5‐NATZ are described and help explain the decomposition process. DNTP contains one of the longest N‐NO2bonds known for a nitramine (1.49 Å). 5‐NATZ was found to be a nitrimine rathe

ISSN:0721-3115    

DOI:10.1002/prep.19910160302

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractTypical reduced smoke type composite propellants mainly composed of hydroxyl‐terminated polybutadiene (HTPB) and ammonium perchlorate (AP) have a drawback that these propellant grains have a high response function of the burning rate to cause acoustic pressure oscillation. The addition of a small fraction (0.5% ∼ 1.2wt%) of zirconium (Zr) or zirconium oxide powders to propellant compositions has been known to be effective for suppressing such a combustion instability. It is also notified, however, Zr powder would incur the acceleration of urethance forming reaction so as to make the pot life of the HTPB/AP propellant dough shorter. This paper reports that tetracycline (TC) is available to offset such a trouble in curing process brought about by Zr powder addit

ISSN:0721-3115    

DOI:10.1002/prep.19910160303

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractFor more than forty years, CERCHARCentre d'Etudes et Recherches de Charbonnages de France.'s activities on explosives and related items have employed a staff of 10 to 20 people including 3 to 5 engineers. This staff, called LSEVLaboratoire des Substances Explosives de Verncuil, acts as the official French laboratory for testing and performing a variety of studies. The main research topics concern the safety in manufacturing of explosives, their transport, storage, and use, particularly in gassy and dusty mines. The same holds for hazardous chemicals that are potentially explosive or otherwise unstable. Related to these activities is the safety of the personnel involved in testing, which requires special attention to be paid to adapted procedures and instructions and to special devices or equipment, desiged for the most part by CERCHAR itself. Three examples of such designe are presented. Their objectives and advantages are disscussed.Thefirst oneis an explosion chamber for firing confined explosive charges up to 2 kilograms. This facility has the possrommy of being highly instrumented. Fragments formed in the detonation of deflagration regimes are totally stopped by the walls of the chamber.Thesecond oneis a cell device for daily storage of explosives. This device led to a very important reduction in the quantity of explosives handled by people in the same room. This avoids a possible catastrophic mass explosion when large samples are needed such as for modern, insensitive mining explosives. the design of the cell structure, based on ful scale experiments, limits an unexpected explosions to the contents of a single cell without propagation to the other cells.The third and last example presented is a movable wood barrier, located in areas where explosives are fired in the open. This barrier ensures a significant reducation in the blast effect. It allows the worker to stay in the immediate vicinty of charge during the final preparation stages i.e the connection of the detonator wires to the firing circuit.

ISSN:0721-3115    

DOI:10.1002/prep.19910160304

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractEffect of addition of carbon in the form of graphite and carbolac on the combustion characteristics of Magnesium‐Sodium nitrate propellant has been studied. Results indicated that the burning rate of the propellant increased significantly by the addition of graphite upto 2%. Thermal decomposition studies revealed that the graphite particles in addition to its absorption of thermal energy being an inert material react with the decomposed products of the sodium nitrate just above the burning surface of the propellant for the exothermic heat release. This heat release which is high at low concentration of graphite is seen causing high burning rate. Any further increase in graphite concentration beyound 2% reduces the burning rate as the thermal energy absorption exceeds the heat release at the burning surface. When carbon in the form of carbolac was used in the composition reactive species diffuse out prior to the sample ignition without participating in the combustion thus reduces the burning rate. The heat of reaction data supported the suggested mechanis

ISSN:0721-3115    

DOI:10.1002/prep.19910160305

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractThermally statble explosives (polynitroaromatic compunds) have been studied using an electric‐spark generating device to determine their sensitivities for acrospace applications. The explosives tested were DATB, TATB, HNS and ONT. In addition, TNT was used as a reference nitro compund. The ignition energy of HNS and ONT does not depend on the initial temperature of the samples as much as does DATB, HNS and ONT are more sensitive than DATB and TATB in electric‐spark test, underwater small scale gap test and drop hammer test, and they also showed high adiabatic flame temperat

ISSN:0721-3115    

DOI:10.1002/prep.19910160306

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractPredicting the jet initiation of an explosive that is covered and in intimate contact with an inert material, is sensitive to the history of the jet in both the cover and the explosive. If the penetration velocity in the cover is subsonic, the acceptor explosive experiences complex wave structures that are significantly different from the case where the penetration velocity is supersonic. The pressure history in the explosive may cause prompt initiation, desensitization, or delayed initiation. We have used transparent polymethylmethacrylate (PMMA) as a surrogate for the explosive, allowing us to experimentally visualize the transition between the subsonic penetration behavior in a steel cover and the quasi‐steady supersonic penetration behavior in the PMMA. The wave histories in PMMA downstream from two steel covers of different thicknesses have been measured by streak and image intensifier cameras and by flash radiography simultaneously. These were augmented with pressure gauges to measure the pressure history for one of the thicknesses. These experimental results and subsequent analysis show how initiation of an explosive acceptor can occur at various distances from the interface, depending on the thickness of the cover plat

ISSN:0721-3115    

DOI:10.1002/prep.19910160307

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractDefinitive conclusions about high and low order reactions can be drawn from individual framing‐mode pictures of a rotating mirror camera record, when both the vellocity of the axial propagation of the reaction along the outer contour and the velocity of radial expansion of the reaction products are analysed at various distances from the plane of initiation. In this, the intensity of the reaction can be assessed quantitatively from the radial expansion velocites, even when, for example, a penetrating shaped charge jet induces an axial drag wave in the test charge. A detailed description is given of the test set‐up and of the test results obtained with charges exposed to the impact of a shaped charge

ISSN:0721-3115    

DOI:10.1002/prep.19910160308

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractThis paper discusses the effect of an opening at the pole of a hemispherical shaped‐charge liner. An experimental study was performed in which various diameter holes were made in otherwise similar shaped‐charge liners. Flash radiographs were taken to observe changes in the liner collapse and the jet characteristics. The collapse process and jet characteristics of a hemispherical liner are significantly altered for a hole diameter which is 10% or more of the outer liner diameter. The jet tip velocity is increased by 26% for a hole diameter‐to‐liner diameter ratio of 0.25. Explanations are presented for the behavior of the tip region of the shaped‐c

ISSN:0721-3115    

DOI:10.1002/prep.19910160309

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

ISSN:0721-3115    

DOI:10.1002/prep.19910160310

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

ISSN:0721-3115    

DOI:10.1002/prep.19910160311

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY