Vol 15 Iss. 16

In existing methods, the plane of the first image of the route is usually taken as the conditional horizontal plane. In this case, it is necessary to take into account the difference in flight altitude in the formulas expressing the distance. It seems simpler to us to take as a conditional horizontal plane the plane passing through the base and the line of intersection of the planes of a stereoscopic pair of adjacent planimetric aerial photographs of one route. We call this base plane the distance plane. The direction of the distances in each pair is slightly different from the vertical direction, since the difference in flight altitudes is small and the photographs are planimetric with a small angle of inclination. The lines of intersection of the planes of the images of a given pair with the distance plane will be parallel to each other and form straight lines of zero distortion of both images in relation to the distance plane.

In Russia, due to the peculiarities of its historical development, in the second half of the last century, a large group of major figures in science and art emerged. The talented geologist Nikolai Alekseevich Golovkinsky belongs to the glorious galaxy of advanced scientists of this time. Having established for the first time a concrete connection between the oscillatory movements of the earth's surface and the process of formation of the sedimentary shell of the earth's crust, he was in this regard a successor of the ideas of the brilliant Lomonosov. He gave the first thoroughly developed scheme in the history of geology for the formation of a layered structure based on the movement of facies in connection with the movement of the coastline. N.A. Golovkinsky was the first to give a clear scheme for the formation of a layered structure and introduced the most important concepts about geological horizons (petrographic or lithological, chronological, stratigraphic and paleontological); he expanded the concept of facies and with all this laid the foundation for the correct understanding and solution of issues of stratigraphic correlation and geological synchronization. The principles of terrace formation (valley formation) formulated by him, which underlie modern geomorphological concepts, are very profound. N.A. Golovkinsky is the immediate predecessor of A.P. Karpinsky in questions about oscillatory movements. A list of scientific works by N.A. Golovkinsky is provided.

One of the main issues in the theory of flotation is the nature of the interaction of the collector reagent with the surface of the floated mineral. It has been established that during the flotation of wolframite and hübnerite in a sodium oleate solution, the pH of the pulp does not increase, but decreases. It has been suggested that as a result of the binding of more and more portions of fatty acid to the surface of the mineral in one solution of sodium oleate, the accumulation of not NaOH, but Na₂WO₄ occurs, which explains the decrease in pH. It has been suggested that the surface of the mineral extracts the fatty acid acyl ion from solution as a result of an exchange reaction between the acid or its soap and the surface of the mineral. Around the monomolecular layer of metallic soap, formed as a result of a chemical reaction on the surface of the mineral, a polymolecular film of undissociated oleic acid is formed, which causes flocculation of wolframite or hübnerite. In the flotation of pure minerals - wolframite and hübnerite - flocculation is a very significant reason for the success of flotation. Flotation of hübnerite with sodium oleate is less successful in comparison with flotation with oleic acid, which should be explained by the different flocculating ability of these reagents.

This question for the case of a homogeneous field—the field of gravity—was discussed in detail by Prof. M.I. Akimov, who found all surfaces that permit the motion of apoint mass under gravity along helical lines with a vertical axis in the presence of friction, and investigated the conditions for these surfaces under which the motion in question would be stable.

The author examines in detail 1) centrifugal fans: fan drive systems, fan control of electric drive units; 2) axial fans, fan drive systems and electric drive control of fan units.

In the history of science, there are many examples where the most important scientific achievements of Russian scientists did not receive sufficient recognition, and the priority for them was attributed to foreigners much later. Very characteristic in this respect is the situation we now have in geology with one very important principle that underlies the correct understanding of the formation of layered sedimentary sequences and the causes of their most important property—stratification. This principle became widely known in the geological literature as the so-called Walther's law. Without intending to deny the great significance of the work of J. Walther in developing questions of stratification and facies, as well as his interesting ideas about the migration and change of fauna depending on the latter, we consider it necessary, on the basis of our special research, to note that these fundamental propositions, which came to be called Walther's law, were by no means first established by J. Walther. The priority for their establishment and development belongs to one of the original and talented Russian geologists—N. A. Golovkinsky. N. A. Golovkinsky and A. A. Inostrantsev are the creators of two opposing concepts in the theory of the formation of layered structure. The essence of these concepts is preserved in all modern views, determining the development of ideas on the formation of layered structure. This development occurs in the struggle between these two concepts and leads to the development of a unified theory of this complex process, in which the concept of N. A. Golovkinsky emerges as the foundation.

Baltic oil shale has long been recognized as a raw material for the chemical and gas industries and as an energy fuel. In this regard, the issues of exploitation of shale deposits and the enrichment of extracted shale are becoming important. The enrichment of shale, which began simultaneously with their extraction, from the very beginning to the present day is carried out in all mines by manual selection of rock (limestone). The use of mechanical (non-manual) enrichment of oil shale is unknown. The question of mechanical enrichment of oil shale arose by analogy with coal and in connection with the sharply increasing scale of its production. Of the mechanical enrichment processes, hydrogravity is the most studied. For a number of reasons, aerogravity and flotation are less studied. The materials obtained as a result of all the studies make it possible to evaluate the Baltic oil shale as an object of enrichment and to identify approximate indicators of their enrichment. This work aims to summarize the materials accumulated over the past 20-25 years on the enrichment of oil shale in the Baltic states and outline a number of conclusions that follow from them.

One of the most pressing problems of modern technology is lightening the weight of metal products. This problem is solved by using light, strong aluminum-based alloys and, wherever possible, replacing heavy copper, nickel and iron alloys with them. It is known from practice that two approaches have emerged for lightening the weight of products and structures. The first approach is the use of light alloys that have sufficiently high strength and corrosion resistance; the second approach is the use of heavy high-quality steels, which, due to their high strength, make it possible to manufacture products with a reduced cross-section. With the progress of modern metallurgy, it becomes clear to designers that plain carbon steel is no longer the only structural material. Alloys based on aluminum and special steels have appeared.