Wyniki wyszukiwania - BazTech

1

Tetraamminecopper(II) Nitrate and Its Effects on Ammonium Nitrate(V)

Künzel M., Vodochodský O., Matyáš R., Jalový Z., Pachman J., Maixner J.

Central European Journal of Energetic Materials

|

2017

|

Vol. 14, no. 1

169--183

EN

Tetraamminecopper(II) nitrate(V) (TACN) is a complex copper salt which is easily formed when ammonium nitrate (AN) comes into contact with copper. It is considered to be an unwanted contaminant of AN because of its sensitivity to mechanical stimuli and significant explosive properties. The formation of TACN by the reaction of copper with molten ammonium nitrate(V) was demonstrated by powder diffraction. Friction and impact sensitivity testing was performed and field experiments were then conducted to reveal the detonation parameters of TACN and its initiation capability towards ammonium nitrate. The dependence of the detonation velocity on charge diameter was revealed and the ideal detonation velocity of 3500 m·s−1 at 0.87 g·cm−3 was measured. AN with the addition of 16 wt.% of TACN was found to detonate when initiated with a small booster charge. Moreover, TACN was able to initiate detonation in fertilizer grade ammonium nitrate(V) under massive steel confinement. TACN should be therefore considered as a possible contributory initiation source in some large scale accidents. In this article, some properties of TACN are revealed which could be useful for the investigation of accidents.

2

Explosive Properties of Melt Cast Erythritol Tetranitrate (ETN)

Künzel M., Matyáš R., Vodochodský O., Pachman J.

Central European Journal of Energetic Materials

|

2017

|

Vol. 14, no. 2

418--429

EN

Erythritol tetranitrate (ETN) is a low melting, solid, nitrate ester with significant explosive properties. The increased availability of its precursor (erythritol), which is now used as a sweetener, has attracted attention to the possible misuse of ETN as an improvised explosive. However, ETN also has some potential to be used as a component of military explosives or propellants. This article focuses on the properties of melt-cast ETN. The sensitivity of the compound towards impact and friction was tested. The explosive performance was evaluated, based on cylinder expansion tests and detonation velocity measurements. The impact energy and friction force required for 50% probability of initiation was 3.79 J and 47.7 N, respectively. A Gurney velocity value of G = 2771 m·s−1 and a detonation velocity of 8027 m·s−1 at a charge density of 1.700 g·cm−3, were found for the melt-cast material. The sensitivity characteristics of melt-cast ETN does not differ significantly from either literature values or the authors’ data measured using the crystalline material. The explosive performance properties were found to be close to those of PETN.

3

Blast Wave Parameters of Liquid Esters of Nitric Acid: Propane-1,2,3-triyl Trinitrate, Propane-1,2-diyl Dinitrate, Ethane-1,2-diyl Dinitrate and Methyl Nitrate

Pachman J., Selesovsky J., Künzel M., Matyas R., Kubat K., Anastacio A. C., Kučera J.

Central European Journal of Energetic Materials

|

2017

|

Vol. 14, no. 2

375--390

EN

A knowledge of blast wave parameters generated by detonating explosives is important for the evaluation of protective measures, modelling validation and post blast analysis. The relevant data are available for solid military explosives, but not for liquid or homemade explosives. In this contribution we present comparison of experimental incident blast wave parameters for bare charges, weighing from 100 g to 1 kg, of liquid esters of nitric acid, including propane-1,2,3-triyl trinitrate (NG), propane-1,2-diyl dinitrate (PGDN), ethane-1,2-diyl dinitrate (EGDN) and methyl nitrate (MeN), amongst themselves and with TNT charges of approximately the same size. The TNT equivalents, determined from both the incident overpressures and the impulse of the positive phase of the blast wave, were above 100% and showed relatively high scatter. The strongest blast wave parameters under otherwise identical conditions were observed for charges of methyl nitrate.

4

OPTIMEX: Measurement of Detonation Front Curvature with a Passive Fiber Optical System

Pachman J., Künzel M., Kubát K., Selesovsky J., Maršálek R., Pospíšil M., Kubíček M., Prokeš A.

Central European Journal of Energetic Materials

|

2016

|

Vol. 13, no. 4

807--820

EN

The ability of a newly developed independent passive optical system OPTIMEX to measure the detonation front curvature is demonstrated on charges of pressed explosive A-IX-1 (RDX/ceresin-stearin mixture with 95/5 wt.%). The charges, with length to diameter ratios of from one to four, were prepared from cylinders with diameters of 21 mm, 30 mm, 40 mm and 50 mm pressed to a density of 1.66 g/cm3. Such charges detonate with a velocity of 8220 m/s. The detonation curvature was obtained using 8 optical fibers and the results were compared with photographs acquired by an ultra-high speed framing camera UHSi 12/24.

5

Optimization of Wall Velocity Measurements Using Photonic Doppler Velocimetry (PDV)

Künzel M., Němec O., Pachman J.

Central European Journal of Energetic Materials

|

2015

|

Vol. 12, no. 1

89--97

EN

The paper describes the measurement of cylindrical charge wall velocity profiles at various angles to the surface normal. The wall velocities were measured using simple zero generation photonic Doppler velocimetry (PDV). The detonation velocity was measured simultaneously using fiber optic probes coupled with a digital chronometer. The PDV probe angles were set in the range of -2° to 17° to the surface normal. Powdered pentaerythritol tetranitrate (PETN) and the PETN-based plastic-bonded explosive Semtex 1A were selected as the explosive materials in order to ensure reliable detonation under the measurement conditions. The explosive charges were confined in thin-walled aluminum tubes with an internal diameter of 16 mm and wall thickness of 2 mm. The results can be useful for the characterization of charge expansion phenomena and also for the optimization of cylinder test measurements using PDV. Gurney constants were determined for both explosives.

6

Effect of polar plasticizers on the characteristics of selected cyclic nitramines

Elbeih A., Zeman S., Pachman J.

Central European Journal of Energetic Materials

|

2013

|

Vol. 10, no. 3

339--349

EN

Dioctyl sebacate (DOS) is a plasticizer used with oily material for the softening of polyisobutylene binder (PIB) to form a polymeric matrix. This matrix was used for the preparation of various plastic explosives. The following energetic cyclic nitramines were used as explosive fillers: BCHMX (cis-1,3,4,6- tetranitrooctahydroimidazo [4,5 d]imidazole), ε-HNIW (ε-2,4,6,8,10,12- hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane), RDX (1,3,5-trinitro-1,3,5- triazacyclohexane), and HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane). For comparison, Fluorel binder was used for the preparation of several plastic bonded explosives (PBXs) based on the same selected explosives. Impact and friction sensitivities of the prepared samples and the pure explosive fillers were measured. The thermal stability was studied using differential thermal analysis (DTA). High performance liquid chromatography (HPLC) was used to detect the presence of BCHMX dissolved in dioctyl sebacate (DOS). The heat of combustion of the prepared samples and of the pure explosive fillers was measured using a bomb calorimetry. The results show that PIB softened by plasticizer (DOS) has a greater positive effect on decreasing the impact sensitivity of the studied pure explosives than Fluorel binder. On the other hand, the plasticizer acts as a solvent for the energetic materials and decreases the decomposition temperature of these plastic explosives.

7

Replacement of PETN by Bicyclo-HMX in Semtex 10

Elbeih A., Pachman J., Zeman S., Akstein Z.

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

|

2010

|

Vol. 1, Nr 2 (2)

7-16

EN

Bicyclo-HMX (BCHMX) was studied in the form of a plastic explosive bonded by the plastic matrix of the explosive Semtex 10 and the results were compared with the original Semtex 10 which contains PETN as an explosive filler. The tests included measurements in the sensitivity to impact and friction. The thermal stability was studied using differential thermal analysis (DTA) with the evaluation of the outputs using the Kissinger method. The detonation velocity was measured experimentally and the detonation characteristics were calculated by means of EXPLO 5 code and the Kamlet & Jacobs method. On the basis of mutual comparison of all the obtained results, it was concluded that replacement of PETN by Bicyclo-HMX enhances the friction sensitivity, thermal stability and the detonation parameters of the explosive Semtex 10, while the impact sensitivity is approximately the same. Calculated results of EXPLO 5 code showed good agreement with the experimental detonation velocities.