Dissociation of nitrogen oxides under the action of pulsed electron beams

The decomposition of nitrogen oxides NO_x in model gas mixtures ionized by microsecond pulsed electron beams was studied. The main decomposition mechanism is the dissociation of oxides caused by the interaction with atomic nitrogen. The final decomposition products are molecular oxygen and nitrogen.     

Removal of acrolein vapor from air by a nanosecond electron beam

Results are presented of an experimental investigation of the decomposition of small quantities of acrolein vapor in air irradiated by a pulsed electron beam. It is shown that the reduction in the impurity concentration as a function of the energy deposited in the gas is satisfactorily approximated by an exponential law. An empirical expression is derived to predict the energy consumption for a given initial acrolein concentration and required degree of purification. Pis’ma Zh. Tekh. Fiz. 24, 35–39 (August 26, 1998)     

Styrene vapor decomposition in air under the action of a pulsed electron beam

The results of experiments on the removal of styrene vapors from air with the aid of nanosecond electron beam pulses and a non-self-sustained volume discharge are reported. The macrokinetic equations based on these results allow the experimental data to be systematized and extrapolated beyond the range of vapor concentrations and deposited energies studied.     

Effect of nitrogen oxides on the sulfur dioxide removal from flue gases under the action of pulsed electron beams

The process of sulfur dioxide (SO₂) oxidation under the action of a microsecond-pulsed electron beam was experimentally studied in model gas mixtures with various initial concentrations of nitrogen dioxide (NO₂). It is shown that the presence of NO₂ significantly affects the process of SO₂ oxidation.     

Influence of the parameters of a pulsed electron beam on the removal of nitrogen oxides from flue gases

Results are presented of an experimental investigation of the oxidation of small quantities of nitrogen oxides in air irradiated by a pulsed electron beam. It is shown that the impurity removal process is strongly influenced by the pulse length and current density of the electron beam. It is noted that an adequate model is needed to describe the plasma-chemical oxidation processes of nitrogen oxides involving charged and excited particles. Pis’ma Zh. Tekh. Fiz. 24, 47–50 (August 12, 1998)     

Luminescence of crystals under the action of a subnanosecond electron beam

Subnanosecond avalanche electron beams formed in air at atmospheric pressure ensure intense luminescence of synthetic ruby and natural spodumene crystals.     

Nitrogen oxides removed from flue gases with sulfur dioxide under the action of pulsed electron beams

The process of a model flue gas mixture purification from nitrogen oxides by microsecond-pulsed electron beam ionization in the presence of sulfur dioxide (SO₂) was experimentally studied. In mixtures with a small SO₂ content, interaction of this component with nitrogen oxides leads to a considerable increase in the specific energy consumption required for the gas purification (∼80 eV per NO molecule). In a gas mixture with approximately equal concentrations of SO₂ and NO, the energy consumption for NO removal decreases to a level close to that in the mixture free of sulfur dioxide.     

Role of interphase processes in styrene vapor removal from airflow under the action of a pulsed electron beam

The conversion of styrene vapor in airflow under the action of a pulsed electron beam has been studied. It is demonstrated that the main processes leading to the removal of styrene from airflow involve reactive oxygen species and yield styrene oxidation products, which are characterized by low vapor pressures and are removed from airflow in a condensed state. This experimental fact can serve a basis for the development of new combined technologies for air cleaning from the vapors of volatile organic compounds.     

Structural transformations in nanoglobular carbon under the action of pulsed high-energy-density electron beam

Exposure of globular (T-900 technical grade) carbon black to submillisecond pulsed electron beam with an energy density of ??40 J/cm² leads to clearly manifested structural transformations of carbon with the formation of highly ordered graphite-like structure and original morphology, as evidenced by the data of high-resolution transmission electron microscopy.     

Use of a pulsed electron beam for air cleaning from methyl methacrylate vapor

The results of experiments on methyl methacrylate (MMA) vapor decomposition in nitrogen-oxygen mixtures under the action of a pulsed electron beam are reported. It is established that there are two competitive mechanisms of MMA removal, with and without participation of active oxygen species.     

Removal of aluminum from metallurgical grade silicon using electron beam melting

Small amounts of metallurgical grade silicon were melted in an electron beam furnace in different experimental conditions in order to investigate the aluminum (Al) evaporation behavior during the electron beam melting (EBM) process. Impurity was significantly decreased in the early periods of melting at 9, 15, and 21 kW. These changes slowed down with the extension of the melting time. Moreover, the removal reaction of Al by evaporation from molten silicon during the EBM process occurred in accordance with the first order kinetics. The calculated mass transfer coefficients of Al at 1941, 1964, and 2051 K increased with the increase of melting temperature. The removal rate of Al was controlled by the transportation of Al from the bulk of silicon metal to the molten/vacuum interface within the range of the experimental temperature.     

Removal of aluminum from metallurgical grade silicon using electron beam melting

Small amounts of metallurgical grade silicon were melted in an electron beam furnace in different experimental conditions in order to investigate the aluminum (Al) evaporation behavior during the electron beam melting (EBM) process. Impurity was significantly decreased in the early periods of melting at 9, 15, and 21 kW. These changes slowed down with the extension of the melting time. Moreover, the removal reaction of Al by evaporation from molten silicon during the EBM process occurred in accordance with the first order kinetics. The calculated mass transfer coefficients of Al at 1941, 1964, and 2051 K increased with the increase of melting temperature. The removal rate of Al was controlled by the transportation of Al from the bulk of silicon metal to the molten/vacuum interface within the range of the experimental temperature.     

On the mechanism of microcrater formation on the surface of a target under the action of a high-power electron beam

The mechanism of microcrater formation under the action of an intense electron beam is theoretically studied for the clean surface of a flat solid target with small perturbations in the form of protrusions or cavities. It is shown that the formation of microcraters is related to the development of instabilities of the Rayleigh-Taylor and Richtmyer-Meshkov types and has a threshold character with respect to the energy deposited in the target. The laws of microcrater formation in the regimes of irradiation corresponding to typical experimental conditions are considered.     

Runaway electron beam generation by a plasma cathode in atmospheric air discharge

Electron beam generation in atmospheric air discharge with a flat cathode has been experimentally studied. The discharge was excited by voltage pulses of negative polarity with an amplitude of 220 kV, a full width at half maximum of 2 ns, and a leading front width of 0.7 ns. The electron beam was monitored using luminescence of a layer of ZnS-CdS:Ag phosphor placed behind a 20-μm-thick foil anode. It was found that the intensity and homogeneity of luminescence of the phosphor layer increased when a dielectric tube with a length smaller than half of the interelectrode distance was placed in the near-cathode part of the air gap. It is concluded that a plasma cathode is formed within the volume confined by the tube and electrons emitted from this region are accelerated in the open part of the gap. In addition, the dielectric tube decreases the divergence of the electron beam.     

High-rate deformation and spall fracture of hadfield steel under action of high-current nanosecond relativistic electron beam

Features of the plastic deformation and dynamic spall fracture of Hadfield steel under conditions of shock wave loading at a straining rate of ∼10⁶ s⁻¹ have been studied. The shock load (∼30 GPa, ∼0.2 μs) was produced by pulses of a SINUS-7 electron accelerator, which generated relativistic electron bunches with an electron energy of up to 1.35 MeV, a duration of 45 ns, and a peak power on the target of 3.4 × 10¹⁰ W/cm². It is established that the spalling proceeds via mixed viscous-brittle intergranular fracture, unlike the cases of quasi-static tensile and impact loading, where viscous transgranular fracture is typical. It is shown that the intergranular character of the spall fracture is caused by the localization of plastic deformation at grain boundaries containing precipitated carbide inclusions.     

Pulsed cathodoluminescence of diamond,calcite, spodumene,and fluorite under the action of subnanosecond electron beam

Amplitude and temporal characteristics of pulsed cathodoluminescence (PCL) of diamond (natural and synthetic), calcite, spodumene, and fluorite have been studied at a temporal resolution of ∼0.3 ns. The PCL was generated by electron beam pulses with a full width at half maximum (FWHM) of 0.1, 0.25, and 0.65 ns. The PCL spectra have been measured for the emission induced by 0.1- and 0.25-ns pulses at a beam current density of ∼90 A/cm².