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Quantitative thermography is used to study the effect of streamwise-orientated, quasi-two-dimensional roughness elements (strips) on the laminar-turbulent transition location on a 45° swept wing model under various test conditions. The efficacy of these sliding roughness elements for flow laminarization is investigated under elevated freestream turbulence levels and increased surface roughness. The results demonstrate that this laminarization method is also robust to moderate variations in the freestream velocity.

This paper presents an experimental investigation of how heat release from homogeneous condensation in a supersonic expanding flow affects the density distribution and shock structure of underexpanded rarefied-gas jets. The results demonstrate that this effect is significant for modeling the force and thermal loads imposed by attitude and control thrusters on adjacent spacecraft components.

We present the SUNSHYNE software package, designed for numerical simulation of compressible gas flows on modern high-performance computing systems, including those accelerated by high-performance graphics processing units (GPUs). The package features a graphical user interface and enables simulations in complex geometries for industrial applications. This is facilitated by versatile boundary condition specification, support for unstructured and block-structured grids, and integration with computer-aided design systems. The paper touches upon the implemented physical models, numerical methods, and functional capabilities of the package. Example simulations are provided, including non-equilibrium flows, direct numerical simulation of transition to turbulence, and heterogeneous detonation.

We develop and implement a numerical model for the dynamic fracture of a functionally graded material (FGM) plate based on St.3 steel and VT8 titanium alloy under shock-wave loading. The simulations employ a three-dimensional finite element formulation within the EFES software package. A mixing parameter is introduced to model the smooth transition in material properties across the plate thickness. A Taylor-type numerical test and a simulation of aluminum projectile impact on a graded barrier are conducted to assess residual deformation, pressure profiles, and spall formation conditions. The St.3 → VT8 gradient direction effectively dissipates the shock wave and suppresses spallation, whereas the reverse gradient causes tensile stress localization and spall fragment formation. The numerical spall thickness values show good agreement with experimental data, confirming the model's adequacy for predicting the dynamic strength of functionally graded structures under high-rate loading.

This paper proposes a mathematical model within the class of generalized continua that account for an internal microstructure. The model considers the inhomogeneous deformation of an infinitesimal volume element. It incorporates plastic slips at the interfaces between these volume elements. Unlike classical continuum mechanics, the formulation introduces additional kinematic degrees of freedom. In the planar case, these are represented by two independent smooth displacement fields, which introduce a length-scale parameter into the constitutive equations, characterizing the internal structure of the medium. The model is applied to numerically solve the problem of stress redistribution in the near-field zone of a system of mine excavations in a rock mass, induced by a specific mineral extraction technology. The results demonstrate that accounting for the material microstructure, which is a feature absent in classical elastoplastic models, shifts a significant portion of the load from the excavation boundaries deeper into the rock mass.

A bilayer Zr_0.85Y_0.15O_2-δ /Ce_0.9Gd_0.1O_2-δ (YSZ/GDC) solid oxide fuel cell electrolyte was first formed on a microtubular NiO/YSZ anode by the reactive magnetron sputtering method. The composite material La₂NiO_4+δ -Ce_0.8Sm_0.2O_2-δ (LNO-SDC) was used as the cathode and characterised using the X-ray diffraction method. The current-voltage characteristics of a microtubular solid oxide fuel cell (MT SOFC) with anode-supporting design featuring a two-layer thin-film YSZ/GDC electrolyte and an air LNO-SDC electrode were measured. The microstructure of a single fuel cell after electrochemical measurements was investigated using scanning electron microscopy (SEM). A comparison with literature data on MT SOFCs that have similar functional layers was made.

The effect of ZnCl₂ on the composition of pyrolysis liquid and the solid pyrolysis product, as well as on the electrochemical properties of the carbonisate obtained during pyrolysis of fir bark was studied. It has been found that destruction starts in the mixture of fir bark with ZnCl₂ at lower temperatures and with lower rates of mass loss than the destruction of fir bark without ZnCl₂, and leads to the formation of a highly porous ZnO/C composite with the specific surface area of up to 770 m²/g. Current-voltage measurements of the samples have shown that the ZnO/C composite has a specific capacitance of 394 F/g, which allows using it for making supercapacitors. The charge accumulation dynamics was revealed to be significantly dependent on the potential scanning rate, and specific capacitance noticeably decreases with its increase. Ion accumulation is assumed to proceed over the surface accessible for ions, and the accessible surface area decreases with an increase in scanning rate because of diffusion-related limitations. The composition of the pyrolysis liquid from initial fir bark and a mixture of fir bark with ZnCl₂ was determined using gas chromatography with mass spectrometric detection, which showed a more complex composition of the pyrolysate for the former case, with a high content of phenol and guaiacol homologues, carboxylic acids and their esters. When using a mixture of fir bark with ZnCl₂, the pyrolysis liquid contains mainly carboxylic acids, predominantly hexa- and heptadecanoic acids, while the homologues of phenol and guaiacol are almost completely absent. It is assumed that ZnCl₂ as a catalyst of Lewis acid type promotes the formation of carbonium ions and the synthesis of more stable high-molecular products.

Increased demand for aluminium around the world is promoting interest in developing alternative technologies for producing aluminium oxide (alumina) from non-bauxite sources, especially from clay. The sulphuric acid decomposition of kaolin clay of the Chovdar deposit (Azerbaijan) has been investigated with the aim of aluminium recovery using the aqueous solution of sulphuric acid as a leaching agent. Before leaching, kaolin clay was calcined at a temperature of 700-750 °C for 2 h. This process involves dehydration of kaolinite, which is the main mineralogical phase of kaolin, and its transformation into metakaolin, an amorphous Al-Si structure from which aluminium is readily leached. The optimal conditions for iron oxide and aluminium oxide leaching by sulphuric acid have been determined, and the degree of recovery was determined for these metals. It has been revealed that kaolin clay leaching to extract aluminium and iron oxides is achieved using kaolin clay samples calcined under the above-mentioned conditions, by treating them with 40 % sulphuric acid for 120 min at a temperature of 95 °C. The degree of Аl₂О₃ and Fе₂O₃ extraction under these conditions is 95.6 and 85.2 %, respectively.

Laser ignition of brown coal samples (rank 2B, Kaychaksky open pit) with rectangular 1-10 ms pulses of the quasi-continuous ytterbium laser YLR-150/1500-QCW-MM-AC (1070 nm, 1.6 kW) has been investigated before and after coal demineralisation. Coal demineralisation is demonstrated to cause an increase in the energy density necessary for ignition.

The mechanism of atmospheric organic aerosol formation in the interaction of the aldehydes emitted by plants with typical urban air pollutants has been investigated. The kinetics of aerosol formation in the aldehyde vapour was studied under laboratory conditions, and the effect of ozone and nitrogen oxides on the rate and mechanism of condensable product formation was determined. The chemical nature of the terminal groups of a growing organic chain was determined to change in the presence of increased ozone concentration. The effect of biogenic aldehydes on the reduction of polluted urban air toxicity was assessed. The field measurements were carried out, revealing the role of vegetation in the reduction of toxic action of anthropogenic air pollutants.