Production of compounded asphalts of improved quality

Paving-and roofing-grade asphalts were obtained at LUKOIL-Permnefteorgsintez Ltd. by mixing peroxidized asphalt and a number of high-boiling unoxidized petroleum products in certain ratios. The asphalts obtained have improved performance characteristics: high plasticity and low brittleness temperature. __________ Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 2, pp. 26–28, May–June, 2006.     

Regular features of wear in heterogeneous structures of high-strength coatings

High-strength coatings on alloys of various morphology prepared by methods of surface impregnation are effective (wear resistant) in operation and economical in production. The requisite structure, wear resistance, and antifriction properties can be provided by a proper choice of the production technology of the coating and the quality parameters of the triboengineering layers, which determine the operating capacity, namely, the geometric (thickness of the coating and depth of the diffusion zone), structural (porosity, phase composition, substructural components), and physical and mechanical (macro- and microstresses, microhardness) parameters and the strength of cohesion with the substrate.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 6, pp. 21 – 25, June, 1996.     

Optical diagnostics of vortex ring–flame interaction

The interaction of a cold vortex ring with flame in an axisymmetric configuration has been investigated using methods of Hilbert optics, shearing interferometry, and numerical simulation. The impact of a cold vortex ring formed by a pressure pulse from the annular area surrounding the source on the flame has been numerically simulated. The modes of breakup of the flame structure, blow-off, and quenching under various conditions of vortex ring formation were identified. It is shown that in the case of both complete and partial quenching, most of the flame is blown off. However, in the case of incomplete quenching of the flame, in its lower part there is a small combustion zone, which then grows back to the previous size.     

A rational approach to processing cerium-containing raw materials

A method for the online control of cerium extraction from rare-earth raw materials based on the oxidation of its trivalent ions with hydrogen peroxide, followed by the precipitation of hydroxide and additional acid treatment to remove trivalent impurities has been considered.     

Stability of the structure of compact zirconium nitride ceramics to irradiation with high-energy xenon ions

X-ray diffraction and transmission electron microscopy (TEM) data demonstrate that irradiation with high-energy ⁺²⁴Xe¹³⁶ ions causes no changes in the grain microstructure of compact zirconium nitride ceramics. According to Raman spectroscopy and high-resolution TEM data, the irradiated ceramics may have local distortions of the zirconium nitride lattice within regions on the order of the lattice parameter in size.     

Investigation of characteristics of planar leaky-wave antenna arrays designed for broadside radiation

The results of computer simulation and experimental investigations of new planar leaky-wave antenna arrays designed for microwave and EHF bands and for the mode of radiation normal to the aperture plane have been presented. These arrays comprise single-layer shielded dielectric waveguides and metal-strip periodic diffraction gratings. The specified antennas ensure the radiation efficiency of no less than 50% and the gain of about 28–30 dB within the 3–4% frequency band.     

Diagnosis of hyperventilation for elimination of false-positive results of physical exercise test

The study was conducted in 55 patients with cardiac pains. Electrocardiography was used successively prior to, during and following physical exercises, followed by Seldinger selective coronary angiography, and electrocardiography prior to, during and following hyperventilation tests. In 2 of 55 patients the result of the exercise test was interpreted as false-positive, since the coronary angiography demonstrated intact vessels, and during hyperventilation ECG recorded a decreased ST segment. To avoid false-positive results in patients with suspected angina pectoris the physical exercises tests can be considered positive only in cases in which hyperventilation caused no ECG changes typical for angina pectoris.