Solution of the Problem of an Acoustically Transparent Body in a Far Field

A solution to the problem of realization of an acoustically transparent body in a far field is proposed using active quenching of the diffracted field by quenching means placed on the surface of the body.     

Development of the Design Model of a Hydrodynamic Lubricating Material Formed during Melting of the Axial Bearing,in the Presence of Forced Lubrication

This work presents a method of formation of an accurate self-similar solution of the problem of hydrodynamic calculation of a wedge-shaped support (slide block, guide) operating in the presence of a lubricating material and melt of the guide. Based on the equation of motion of an viscous incompressible liquid for a “thin layer” and the expression for the energy dissipation rate, an analytical dependence is obtained for the profile of the melted surface of the guide. In addition, the main performance characteristics of the friction couple considered are defined. The influence of the parameter specified by the melt of the guide on the bearing capacity and friction force is estimated.     

Spectral-Spatial Methods for Hyperspectral Image Classification. Review

Various methods of spectral-spatial classification of hyperspectral data are reviewed. Papers devoted to the most popular ways of using spatial information for increasing the accuracy of classification maps are considered. It is shown that the best results are obtained by using preprocessing of “raw” data before the procedures of pixel-wise spectral classification. Disadvantages, limits, and possible directions for developing existing methods are investigated and analyzed.     

Evaluation of the mechanical characteristics of soils from static-penetration data

Conclusions 1. The specific resistance of soil not only beneath the cone of the penetrometer but also against the friction couple should be used to define the prediction of the strength and deformation characteristics of silty-clayey soils more precisely from static-penetration data, and the type of clayey soils should also be considered for the strength characteristics.2. For penetrometers equipped with radiation-logging apparatus, it is possible to evaluate mechanical characteristics of soils under field conditions, using the soil's density in addition to the penetration parameters q and f.3. In developing regional statistical relationships, it should be remembered that the extent to which q and f influence . c, and E is determined largely by what types of soil the statistical sample represents and in what range the physical indicators of its conditions vary.4. To define the recommendations of Construction Rule and Regulation 1.02.07-87 more precisely, it is expedient to use resultant correlation relationships (6)–(8) to evaluate , c, and E from static-penetration data for the genetic groups of quartenary deposits investigated.Translated from Osnovaniya, Fundamenty i Mekhanika Grungov, No. 4, pp. 21–24, July–August, 1990.     

Regulation of carbon potential in case-hardening units using electrochemical sensors and microcomputers

Scientific-Production Union "VNIITMASh." Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 5, pp. 21–24, May, 1990.     

Strain aging in the surface layers of low alloy steel

Conclusion Investigation of the process of anomalous strain aging in the surface layers of low carbon, steel after grinding and lengthy aging confirmed the decisive role of carbon in the change of the mechanical properties of the surface layers and of their physical state.The microhardness of steel (0.033% C; 0.010% N) after aging for one year more than doubles in the surface layers 6–8 m thick. Across the layer it changes nonmonotonically; hardness changes most in the surface layer 1–2 m thick.The effect of strain aging of steel is associated with the gradual development of a mosaic structure in the crystal grains, caused by the redistribution of dislocations. The magnitude of misorientation of substructural elements of the grains, evaluated according to the size of the interference spots on the x-ray photograph, changes during aging from a few to tens of degrees.The change of properties of the subsurface layers in time is apparently caused by hydrogenation that occurs when steel is ground, and by the subsequent process of redistribution of impurity elements, causing a high degree of lattice distortions in it.Engineering Institute, A. A. Baikov Institute of Metallurgy. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 11, pp. 32–38, November, 1990.     

Surface wear of a plate in the cone-plate frictional pair of an expansion system

The surface wear of the plate the cone-plate frictional pair in an expansion system is investigated.     

Multilayer Composites Based on PTFE Films and Fiberglass

Fibre Chemistry - The article is devoted to the development of two-layer composites with a fluoroplastic matrix and fiberglass reinforcing elements. The fluoroplastic matrix acts as a protective...     

Investment casting of NiAl single-crystal alloys

Significant progress has been made in the understanding of solidification conditions, microstructure evolution, and defect formation during investment casting of NiAl single crystals. The high liquidus temperatures of NiAl alloys result in a larger dendrite arm spacing than is found in superalloy René N5. Because of their higher thermal conductivities, NiAl alloys have higher cooling rates and lower temperature gradients during solidification than René N5. These differences give NiAl alloys a lower tendency to form freckles and a higher tendency to form equiaxed grains. However, with the aid of process modeling, single crystals of various shapes of NiAl alloys have been produced.     

Properties of maraging steels after high-temperature treatment

Conclusions For the optimal structure of austenite in maraging steels they should be subjected to rolling with a final rolling temperature not over 900°, rapid heating to Ac₃+30°, and rapid cooling.Institute of Solid State Physics, Academy of Sciences of the USSR. I. P. Bardin Central Scientific-Research Institute of Ferrous Metallurgy. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 4, pp. 31–33, April, 1981.