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Several thermocirques have been detected in the Oymyakon Upland, in the basin of the upper reaches of the Indigirka River, based on space imagery. Two of these thermocirques were studied in the Suntar River valley. The thermocirqures formed in 2014-2016 after an increase in precipitation, and they continued to grow at a rate of 5-35 m/year until 2023-2024. Currently, they are 130-220 m long. The thermocirques were formed on the slope of a terminal moraine hill at an absolute height of approximately 900 m. The moraine deposits exposed in the back wall of the larger thermocirques consist of clastic material ranging from gravel to large boulders and blocks with a sandy-loamy fill. Two cryofacies were identified in the upper 5 m of the section based on their cryogenic structure: the lower cryofacies is an initially frozen moraine with a primary cryogenic structure, while the upper cryofacies is a taberated deposit of the lower cryofacies that has been re-frozen. Epigenetic ice wedges up to 2.5-3 m wide penetrate from the contact between the cryofacies, forming polygons with a size of approximately 30 m. It is assumed that the terminal moraine was formed during the first cryochron of the Late Pleistocene and is stratigraphically associated with the Yugler horizon, while partial thawing occurred in the first half of the Holocene.

Samples of Jurassic coal-bearing rocks from the Ulug-Khem Coal Basin (Republic of Tyva, Russia) and from the Angren coal mine (Uzbekistan) were investigated. These rocks contain numerous leaf remains of leptostrobaleans. The material from Angren is represented by a mass of numerous leaf fragments of Phoenicopsis taschkessiensis and Czekanowskia eugeniae (Leptostrobales) forming the leaf litter. The hydrocarbon composition of the rock extracts was studied. All the samples showed high concentrations of C₃₃ and C₃₅ n‑alkanes. The rock extract contains high concentrations of abietic acid derivatives such as dehydroabietanes, simonellite, retene, and norisopimarane indicating a relationship between leptostrobaleans and conifers by their biochemistry. Retene was found in a more mature sample from Tyva, containing abundant leaf remains of Czekanowskia tuvensis. The extract of a rock sample from Tyva contains aromatic secobicadinans, which are the major components of the aromatic fraction. Their connection with leptostrobaleans was excluded based on comparison with samples from Angren; however, their botanical affiliation is not obvious. The discovery of polycadinene resin derivatives in the Middle Jurassic material from Tyva indicates that they were probably produced by some groups of Jurassic plants.

Thermodynamic calculations were carried out to model the process of interaction between fluid with different concentrations of fluorine and the mineral association calcite + monazite (in the presence of barite and celestine), in order to establish how fluorine concentrations in the fluid change the initial mineral association and the forms of REE concentration during the formation of carbonatite complexes. Thermodynamic calculations were carried out at temperatures of 500, 400, 300, 200 and 100°C and pressures of 2000, 1000, 500, 250 and 125 bar in the range of fluorine concentrations of 10^-4 – 1 mol/kg H₂O. It has been established that when monazite and calcite are exposed to an acidic (pH 3) fluoride-carbonate-chloride solution, increasing fluorine concentrations result in the formation of REE-containing fluorapatite, fluorite, and the fluorocarbonates – bastnasite and parisite. Fluorocarbonates begin to form in equilibrium with decreasing temperature, beginning with decreasing fluorine concentrations in the initial solution. Formation of parisite, according to the generalized formula CaLn₂(CO₃)₃F₂, requires twice as much fluorine as that for bastnaesite LnCO₃F, and under acidic conditions, it appears only at 200 and 100°C in the range of 0.01–0.1 m HF. At the highest concentration considered (1 m HF), REE-fluorapatite, along with parisite, also disappears from the equilibrium assemblage due to the maximum possible amount of the third calcium consumer, REE-containing fluorite. Lowering the temperature increases the stability of REE-fluorite by reducing the fluorine concentration required for its formation in the fluid. With increasing pH of the ore-forming environment, the formation of parisite at 200°C is observed even at low HF concentrations (0.0001 m), replacing bastnaesite under these conditions. Increasing pH is also accompanied by increased stability of REE fluorite and the appearance of strontium-bearing calcite and hydroxyapatite in fluorine-poor fluids. In an acidic fluoride-carbonate-chloride solution, after its interaction with the monazite+calcite assemblage, the total concentration of lanthanides (Ln _tot) decreases with decreasing temperature. Starting at 400°C, the Ln _tot curve exhibits a complex dependence on the initial HF concentration and reaches its minimum at maximum m HF. The main contribution to Ln _tot comes from the chloro- (at low m HF) and fluoro- (starting at 0.01 m HF with decreasing temperature) complexes of light REEs. The contribution of heavy REEs is approximately three orders of magnitude lower than that of light REEs.

The paper presents experimental results from a study on supersonic flow across a cylinder. Selected measurements of pressure on the cylinder surface were taken. Different variants of jet blowing were tested with a focus on variation in the pressure distribution on a surface. The difference between variants was in positioning the blowing hole on the cylinder circumference in the mean cross-section. The paper describes the influence of the hole position on the pressure distribution for a case of interaction between a supersonic free stream and a jet. New experimental data on a pressure distribution on a circular cylinder surface with at different positions of the blow hole are now available.

Experimental data on the nature, thermophysical parameters, and boiling modes of closed two-phase evacuated water-filled thermosyphons are presented, and their application prospects are discussed. The high efficiency of thermosyphons in slug and hyperslug modes is experimentally confirmed.

Bubble motion in an inclined circular pipe with a cocurrent liquid flow was experimentally studied. The effects of low concentrations of surfactants, the channel inclination angle, and the flow velocity on the size of gas bubbles and their ascent velocities were determined. It was found that the combination of liquid flow and surfactant significantly suppresses bubble coalescence. For the given conditions, the drag coefficient of a bubble rising near the wall was calculated. It was shown that the drag coefficient is inversely proportional to the Weber number both in pure water and with the addition of surfactant.

The article studies the intensification of heat transfer during cooling of a surface modified by laser treatment with a dispersed coolant flow. A laser ablation technique using a pulsed laser is described, leading to the formation of craters up to 600 μm in diameter on a copper surface with the following roughness parameters: Ra = 1.48 μm, Rz = 9.8 μm. The results show an increase in the removed heat flux by 35-40%, the heat transfer coefficient by 38-55% in the intense boiling mode (115-125 °C) compared to the unmodified surface. The proportion of heat removed due to the phase transition reaches 90% at a removed heat flux density of 8.4 MW/m², on the modified surface.

The development of non-stationary thermal gravity-capillary convection in a layer of ethyl alcohol with a free surface after sudden electric heating of one of the vertical walls of a rectangular cavity was experimentally studied. The effect of a heated liquid flow along the free surface onto the opposite thin metal wall of the cavity was studied. The influence of the liquid layer heights and heat flux densities on the heated wall of the cavity was investigated. Temperature fields on the thin wall and on the free surface of the liquid layer were measured using a FLIR x6530sc thermal imager. Computer processing of thermal imaging films allowed the construction of distributions of temperature and temperature gradients along the wall height depending on time. The amplitude-frequency characteristics of temperature pulsations associated with the occurrence of secondary flows in the heated liquid flow on the wall were determined, and their effect on instantaneous temperature fields on the wall was studied against the background of a monotonic change.

Multi-rotor aerial vehicles have the rather short history of active usage, so many aspects of vehicle aerodynamics remain poorly investigated. One of these aspects is a problem how the rotor-generated flow affects the elements of framework ad body of a multi-rotor copter. The paper studies the influence of rotor rotation on the aerodynamic drag coefficient and the sideforce acting on the body of a meteorology drone (body with a spherical shape). Calculations were performed in the RANS statement with a direct account for the rotor rotation. Numerical results are verified on the base of PIV-measurements. The aerodynamic characteristics of the quadcopter body depend significantly on the unsteady flow generated by the rotors.

Some properties of vortex filaments in a weakly nonideal countercurrent Bose-Einstein condensate (BEC) are described. This paper focuses on the study of reconnection processes and the equations of motion. One of the motivations for this study is that the dynamics of quantum vortices in superfluid helium has been obtained at the phenomenological level, and a number of questions requiring clarification can be addressed by studying the corresponding problem in BEC. Considering a vortex filament as the intersection line of surfaces where the real and imaginary parts of the macroscopic wave function ψ(r, t) vanish allowed us to write an equation of motion for the vortex filament. Remarkably, the structure of this equation completely coincides with the structure of the equation for the dynamics of a vortex filament in superfluid helium, which was derived from entirely different, phenomenological considerations.