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Experimental studies and analysis of silicate inclusions testify to the magmatic genesis of part of chromian spinel from the Triassic deposits of the northeastern Siberian Platform. The compositions of melt inclusions in the chromian spinel show the participation of alkaline (potassic) magmas in their crystallization. Most data indicate the presence of magmatic systems similar to melts in the Guli ultrabasic massif in the northern Siberian Platform. Studies of the distribution of trace and rare-earth elements in the melt inclusions show the existence of several magmatic systems. These are, first of all, magmas that formed Guli-type ultrabasic massifs and gave rise to meimechites and picrites in the Maimecha-Kotui province. There are also plume-related magmatic systems with kimberlites, lamprophyres, and/or other continental “hot spots”. The composition of the melt inclusions suggests the existence of several types of the primary sources of chromian spinel in the northeastern Siberian Platform, which confirms the earlier data on the heterogeneous composition of the deposits of the diamondiferous Carnian (Upper Triassic) Stage. Applying computer modeling with the well-known COMAGMAT, PETROLOG, and WinPLtb programs as well as the Ol-Sp geothermometers based on the melt inclusions in chromian spinel from the Triassic deposits of the northeastern Siberian Platform, we have determined the P - T conditions of crystallization of minerals in the igneous rocks being the sources of the examined chromites. The temperature of liquidus crystallization of chromian spinel is 1324-1275 ºC. The P - T conditions of formation of olivine and clinopyroxene inclusions in it are estimated at ca. 4.5-4.1 kbar, 1510-1150 ºC and 3.2-1.0 kbar, 1285-1200 ºC, respectively.

Two schemes of shock tunnels and results of experimental investigations of cumulation of liquid cylindrical shells in a rotating system are presented. The first scheme is used to study one-dimensional compression (classical cumulation) of a rotating cylindrical shell under explosive loading by an annular piston. Experimental results are estimated with the use of the model of dynamics of one-dimensional cylindrical cumulation in a quiescent unbounded liquid. In the second scheme, a bore jump is found on the inner surface of the rotating gas cavity; this structure is formed by the piston in the case of shock loading of the gas cavity and its downstream propagation along the axis of symmetry.

An equation of the dynamics of formation and radiation of a quasi-empty oscillating cylindrical cavity in a fluid is derived for the first time with due allowance for the changes in the velocity of sound and the volume fraction of cavitation nuclei. A dimensionless formulation of the problem is proposed and analyzed under the condition of identical pressures in the cavitation zone and inside the cylindrical cavity at its boundary. As a result, a dynamic relationship between the volume fraction (velocity of sound) in the cavitation zone and the radius of the cylindrical cavity is found.

It is shown that the “new methodologies” of processing and using results calculated for rotating detonation engines, as well as those of recent measurement of forces acting on the models of ramjet (rotorless) models in “hot” and “cold” runs in supersonic test benches, which are developed and promoted by S.M. Frolov and V.I Zvegintsev with their colleagues, are incorrect.

The traditional approach to measuring the thrust of air-breathing jet engines (ABJEs) was proposed by B.S. Stechkin in 1929. In this approach, the thrust is determined as the difference between the momenta of the gas flows at the engine inlet and outlet. The approach involves some methodological and terminological problems. Based on a critical analysis of available concepts, the present article proposes a new approach to determining the ABJE thrust in the form of the decrease of the initial drag of the aircraft + ABJE system when the power plant operates with fuel supply and energy release. For the thrust thus obtained, we propose using the term “real thrust”. It is shown that the proposed approach eliminates terminological problems and simplifies the technique for measuring the thrust characteristics of the ABJE. The paper considers various options for applying the proposed approach to the determination of the “real thrust” for different cases of using and modeling ABJEs, including the calculation of flight trajectories of the aircraft with ABJE.

We present the experimental results on the thermal efficiency in a wall gas screen injected through inclined cylindrical holes along a smooth surface, and when a secondary flow is blown through cylindrical holes into a transverse trench. The thermal efficiency fields of the wall screen were measured using an infrared camera. In the case of blowing into a trench, the experimental data are characterized by an insignificant influence of the injection parameter on the thermal efficiency of the wall screen for all the trenches under study. It has been established that an increase in the trench depth leads to an increase in the thermal efficiency of the wall gas screen. The maximum increase in thermal efficiency is achieved for a trench with relative depth h/d = 0.94 . The data of the measurements presented are compared with the experimental and numerical results of other authors for the cases of injecting through the holes into a transverse trench.

Results of experimental and numerical studies of the properties of a turbulent boundary layer modified with a control action in the form of distributed air blowing through a high-technology perforated wall are presented. The wall is part of the surface of an elongated axisymmetric body in a low-velocity gas flow. The Reynolds number Re^** based on the momentum thickness δ^** ahead of the perforated region formed by holes 0.14 mm in diameter with microchannels with a small aspect ratio is 2660. The area-averaged blowing coefficient C_b varies in the interval 0 - 0.00885. As the streamwise coordinate increases up to the distance 550δ^** from the blowing region, the local friction is seen to decrease consistently; the greatest value of the local friction is 64% directly in the blowing region in the case of the maximum blowing intensity.

The thermal conductivity of the R-32/R-125 (15/85) mixture was investigated in the temperature range of 305 - 411 K and pressures of 0.1 - 1.8 MPa. Measurements were carried out by the stationary method of coaxial cylinders. The error of the experimental data on thermal conductivity was 1.5 - 2.5%, and the measurement errors of temperature and pressure did not exceed 0.05 K and 4 kPa, respectively. A generalizing equation for calculating the thermal conductivity as a function of pressure and temperature was obtained. The thermal conductivity on the condensation line and in the ideal gas state was determined.

The paper studies the segmented flow modes of immiscible liquids in microchannels with T- and X-shaped inputs for 3D printing technologies. On the basis of the flow visualization results, mode maps with a distinguished area of stable plug flow are constructed. A fair coincidence of the maps built on the basis on the superficial flow velocities is revealed, and the influence of the channel input on the boundaries of flow modes is shown to be insignificant. When using a less viscous carrier phase, the region of a stable plug mode is demonstrated to expand towards higher superficial flow velocities. The separation of microdrops from the trailing edges of plugs is investigated. It has been found that the transition to the separation of microdrops is described in terms of the capillarity number, constructed from the bulk velocity of the phases, and the ratio of phase flow rates. Thus, a range of dimensionless parameters of microchannel devices, suitable for 3D printing of composite materials with specified properties has been determined.

The author focuses on complex loading of a granular material at continuous rotation of the principal strain axes. The described testing procedure reveals the stress dependence on the relative velocity of rotation. It is possible to use the velocity of rotation of a unit volume relative to the velocity of rotation of the principal strain axes in the constitutive equations for a continuum.