Explosive decomposition of heavy-metal azides

A real-time investigation of the explosive decomposition of heavy-metal azides is reported. A multichannel instrument configuration designed specifically for the goals of the study is described; it is capable of measuring the transient conductivity and the spectral and kinetic characteristics of the luminescence and absorption of exploding samples with nanosecond time resolution. New phenomena are discovered and analyzed in detail: the predetonation conductivity and predetonation luminescence of heavy-metal azides. The conductivity of silver azide in the predetonation state is used to make an experimentally justified decision as to whether the explosion is driven by a thermal or chain mechanism, in favor of the latter. The sum-total of the new data provides the basis for the development of an experimentally justified model of predetonation luminescence and the explosive decomposition process of heavy-metal azides, including the following principal stages: hole trapping by a cation vacancy, reconstruction of the center as a result of chemical reaction with the formation of a quasi-local hole state in the valence band, hole detrapping from the reconstructed center, carrier multiplication as a result of impact ionization by hot holes, and reconstruction of a local state in the bandgap, thereby establishing conditions for repetition of the investigated chain of processes. Zh. éksp. Teor. Fiz. 116, 1676–1693 (November 1999)     

A method of summation of divergent series to any accuracy

We propose a new method of summation to any accuracy for a wide class of divergent series, using only a finite number of terms of the series. Translated fromMatematicheskie Zametki, Vol. 68, No. 1, pp. 24–35, July, 2000.     

On shock initiation in brisant explosives by a high-current electron beam

The feasibility of shock initiation in thin pentaerythritol tetranitrate (PETN) single crystals under the action of a pulsed high-current electron beam (0.25 MeV, 20 ns, 15 J/cm²) is shown experimentally. The real-time dynamic characteristics of crystal glow arising under the action of the electron beam and glow due to subsequent shock-wave-induced transformations are presented. A shock wave results from beam energy absorption and initiation of an exothermal chemical reaction in the irradiated layer.     

Spectrokinetic characteristics of light emission from pentaerythritol tetranitrate single crystals detonating under the action of a high-current electron beam

The spectrokinetic characteristics of light emission from pentaerythritol tetranitrate exposed to an electron beam pulse (0.25 MeV, 20 ns, 15 J/cm²) are measured in real time. It is shown that, during the impact of an electron beam, cathodoluminescence from the sample is observed. Light emission from PETN explosion occurs on the microsecond time scale. Spectral pyrometry measurements processed in the Wien coordinates yielded a sample explosion temperature of T ≈ 3000 K.     

Efficiency of laser initiation and absorption spectra of PETN

A comparative study of the efficiency of the laser initiation of PETN by the first and second harmonics (1060 and 530 nm) of a neodymium-doped phosphate glass laser was performed. A significant difference in the efficiency of PETN initiation by the different harmonics was revealed: as the initial temperature of the sample increased from 373 to 450 K, the threshold initiation fluence decreased from 3.0 to 0.5 J/cm²; at the same time, the second harmonic failed to initiate PETN even at a fluence of 10 J/cm². The absorption spectrum of PETN was found to have a weak absorption band with a maximum at λ _m = 1020 nm. It was assumed that the high efficiency of initiation by the first harmonic is associated with light absorption (photo-initiation) by this band     

Pressure of the products of the explosive decomposition of a mixture of pentaerythritol tetranitrate and nickel monocarbide nanoparticles initiated by laser radiation

Relative characteristics of the pressure created by the products of explosive decomposition of a mechanical mixture of pentaerythritol tetranitrate and nickel monocarbide (NiC) nanoparticles upon laser initiation are determined. It is demonstrated that the explosion of the mechanical mixture is caused by the absorption of laser radiation by NiC nanoparticles, a process accompanied by the heating and exothermic decomposition of NiC to the nickel and carbon phases, which, in turn, give rise to the formation of hotspots. The optimal concentration of NiC at which the maximum pressure of the explosion products is achieved is determined.     

Specific features of explosive decomposition of pentaerythritol tetranitrate exposed to an electron beam with an explosive emission cathode

A comparative examination of the critical energy density of explosive decomposition of pentaerythritol tetranitrate exposed either to an electron beam of a GIN-600 accelerator (240 keV, 20 ns) with an explosive emission cathode or to this beam combined with metal low-temperature diode plasma has been performed. It has been demonstrated that the contribution of plasma to the development of explosive decomposition is appreciable at explosion probabilities P ≤ 0.2. At higher energy densities and explosion probabilities P ≥ 0.5, the contribution of plasma to the overall beam energy density did not exceed 10%.     

The stability and limits of human population growth

We propose a model of human population dynamics based on kinetic approaches and the general principles of the Lyapunov stability theory. The model has a stable stationary solution. An analysis of the proposed model gives estimates of the model coefficients, limits of human population growth, and characteristic time needed to reach these limits.