Effect of a Gas Discharge on the Ignition in the Hydrogen-Oxygen System

A kinetic model is constructed for ignition initiated by nonequilibrium gas-discharge plasma in the hydrogen-oxygen system. The model takes into account the effect of the electric field on the dissociation of molecules and on the buildup of active radicals, excited species, and charged species (electrons and positively and negatively charged ions). It is demonstrated by mathematical modeling that the induction period depends strongly on the reduced strength of the electric field (electron temperature). Four reduced kinetic networks are considered, and various components and reactions are shown to exert an effect on the nonthermal initiation of ignition in the H₂-O₂ system by low-temperature plasma.     

Electrochemical Emission during Discontinuous Creep of Aluminum‒Magnesium Alloy

Crystallography Reports - It is experimentally established that the discontinuous creep of aluminum?magnesium alloy AlMg6, deformed in an aqueous medium, is accompanied by discrete...     

Microwave discharge on the surface of a dielectric antenna

A microwave discharge initiated by a surface wave on a dielectric body placed in a supersonic air flow is studied. The discharge is shown to represent a thin plasma layer that uniformly covers the antenna surface. In experiments, the discharge propagation velocity may be as high as 100 km/s, which is several orders of magnitude higher than the velocity of sound in air. The peak pulse power necessary to excite the discharge in a wide range of air pressures (from 10⁻³ to 10³ Torr) is no higher than 100 kW. It is shown that the gas temperature may rise to 1000–2000 K, rapidly increasing (with a rate of ≈50 K/μs) at the early stage of discharge evolution. The discharge of this type may find applications in super-and hypersonic plasma aerodynamics (such as control of the flow near the surface of a body moving in a dense atmosphere, reduction of surface friction, optimization of ignition and combustion conditions for supersonic flows of gaseous fuel, etc.). It may also be used to advantage in development of new-generation plasma sources for micro-and nanoelectronics purposes (plasma treatment of surfaces, etching, and film deposition).     

Determination of the non-constant component of the ion mobility using the spectrometer of ion mobility increment

A new method for determination of the non-constant component, alpha(E), of an ion mobility, k(E), is suggested. The method uses the relationship U(C) (US) that can be experimentally obtained with a spectrometer of ion mobility increment with planar drift chamber. (UC is a compensating voltage, U(S) is separating voltage amplitude.) A general equation for alpha(E) has been derived. We have explored the possibility of determination of alpha(E) from the experimental data for different types of US(t). In two specific cases, analytical solutions have been obtained.     

Effect of surface kinetics on the dendritic growth of ice in supercooled water

The dendritic growth of ice in supercooled water was investigated experimentally. It has been found that, with an increase in the degree of initial supercooling of water, the data of measuring the growth rate of the dendrite tip v _t, the average distance between the tip and the first side branch z? _SB, and the fractal dimension d _f of the dendrite contour diverge from the analytically and numerically calculated parameters of dendritic growth. It is shown that the discrepancy between experiment and theory is due to the transition from the diffusional growth to the growth controlled by the surface kinetics. The nature of the anisotropic surface kinetics of ice growth in supercooled water is discussed.     

Effect of Laser Processing on Strength and Portevin–Le Chatelier Serrated Deformation of Aluminum Alloy

Physics of the Solid State - The effect of surface processing by laser IR radiation on strength and Portevin–Le Chatelier serrated deformation of AlMg6 aluminum–magnesium alloy is...     

Effect of an aggressive medium on discontinuous deformation of aluminum–magnesium alloy AlMg6

It is experimentally shown that the molecular (chemical) process of surface etching of deformed aluminum–magnesium alloy AlMg6 causes the development of a macroscopic plastic strain step with an amplitude of a few percent. Using numerical simulation of the polycrystalline solid etching process, it is shown that the corrosion front morphology varies during etching from Euclid (flat) to fractal (rough). The results obtained show the key role of the surface state on the development of macroscopic mechanical instability of a material exhibiting the Portevin–Le Chatelier effect.     

Inflammation dynamics of thin alcohol films under the action of a surface microwave discharge initiated in atmospheric-pressure air

Rapid nonthermal plasma-stimulated inflammation of liquid hydrocarbon (alcohol) films is realized under the conditions of a surface microwave discharge initiated in quiescent atmospheric-pressure air. The induction period is found, and the velocity of the intense combustion front is determined. Combustion is initiated by the low-temperature plasma of the surface microwave discharge that exists at high values of the reduced electric field. It is shown that the induction period varies between 10 and 100 μs depending on the input power, the plasma-stimulated inflammation occurs on the antenna at the site where the surface microwave discharge burns, and the velocity of the intense combustion front near the antenna reaches 300–350 m/s.