An express method of measurements of parameters of technological electron beams

An express method of direct measurements of the current density distribution of axially symmetric electron beams is proposed. It is shown that use of the technique is urgently needed to improve the reproducibility of the results of electron-beam processing. Comparative analysis of existing methods to measure the parameters of electron beams used for technological purposes is carried out. A technique to restore a radial distribution of electron beam current density as well as a device to implement the technique is developed. The results of radial distribution recovery are analyzed in the case in which the initial distribution is given in the form of a model function of normal distribution. An algorithm to determine estimated sizes of the area within which spatial distribution discretization is carried out is developed. Based on analysis of the experimental dependences, it is shown that the suggested numerical method can be applied to all types of axial-symmetric distributions. The nature of errors occurring after distribution function recovery is analyzed. A technological projection of express diagnostic systems for the processing electron beams is made taking into account parameters of the existing element base.     

Features of construction of manipulators for electron-beam welding installations

The features of the construction of multicoordinate manipulators for moving welded products in precision electron-beam welding installations are considered. The kinematic circuits of manipulators, the types of stepping motors, and the circuit of the control system over the multicoordinate moving of welded products are presented.     

Analysis of fuel consumption by mining-concentration combines

All-Union Scientific-Research Institute of Heat Engineering in Ferrous Metallurgy (VNIIMT). Translated from Metallurg, No. 2, pp. 30–31, February, 1990.     

Effect of chemically active additives on the detonation wave velocity and the detonation limits in lean mixtures

On the basis of the formalism of the one-dimensional theory of detonation with heat losses and the theory of branched-chain processes by the example of the oxidation of hydrogen-air mixtures in the presence of a hydrocarbon additive, it is shown that taking into account the reactions of termination of reaction chains on molecules of the additive, trimolecular termination, and also chain oxidation of the hydrocarbon additive allows one to qualitatively describe both the passage of the detonation velocity through a maximum with an increase in the additive content of a lean mixture and the existence of two concentration limits of detonation.     

Improvement of the electrohydraulic power controller of an arc furnace in foundry

Experimental data are used to develop a model for the structure of an adaptive electrohydraulic power controller for an arc furnace, and the introduction of a negative electrode velocity feedback into the electrohydraulic drive of electrode motion is shown to be useful. Model investigations of the operation of the proposed power controller under various conditions are performed, and recommendations are made to choose the parameters in designing power controllers.     

Effect of inert and reactive admixtures on the initiation and propagation of laminar spherical flames

The initial stage of the propagation of discharge-initiated laminar spherical flame in stoichiometric natural gas- and isobutylene-oxygen mixtures containing krypton or carbon dioxide and in the hydrogen-air mixture at atmospheric pressure in a constant-volume bomb has been investigated by high-speed color cinematography. Dilution of the combustible mixtures with the admixtures increases the steady-state flame front formation time by a factor larger than 10. The phlegmatizing effect of carbon dioxide on hydrocarbon combustion is stronger than that of krypton. For given combustible mixtures, the ratio of steady-state flame front formation times is inversely proportional to the ratio of the temperature rise values for the flames. The introduction of a minor amount of a reactive admixture (1.2% isobutylene) into the stoichiometric hydrogen-air mixture greatly increases the steady-state flame front formation time.