The aim of this work was to develop, characterize and apply in a laboratory-on-plate format a new metal-affinity sorbent based on cobalt (II) stearate thin monolayers (films) — FCo. FCo were prepared by the classical Langmuir method and then collapsed. A bath with movable barriers was filled with an aqueous solution of CoCl₂. A solution of stearic acid in hexane was dropwise applied to the surface of the aqueous subphase. The solution spread over the surface, forming a film (layer). After evaporation of hexane from the aqueous subphase, a monolayer of cobalt (II) stearate was formed on the surface, which was slowly compressed by movable barriers. The following parameters were determined for FCo prepared by the classical Langmuir method and then collapsed: specific mass (0.022 ± 0.003 mg/dm²), specific surface area (22.0 ± 2.1 m²/g), isoelectric point value (3.7 pH), moisture content (63 ± 2%), structures ([Co(C₁₇H₃₅COO)₂]H⁺), chemical stability (stable in standard aqueous eluents and in polar organic solvents used in metal-affinity chromatography). Adsorption isotherm of the diclofenac from aqueous solution on FCo was investigated in spin columns (batch). The FCo structure can be obtained on the surface of a subphase drop deposited on a MALDI target plate. Thus the sorbent is formed directly on the surface, preserving the structure and metal-affinity properties. The technique is characterized by cost-effectiveness, simplicity and reproducibility. FCo formed on spot of MALDI target plate provide a high level of sensitivity, specificity and selectivity of the analysis, it is shown that HHb adducts with chlorine-containing alkylating agent can be determined at 0.5% protein modification. Thus, a comprehensive approach for the enrichment of chlorine-containing HHb adducts using a cobalt (II) stearate monolayers on MALDI target plate has been developed.

The organic carbon content is one of the marker indicators for wastes of mining, processing and combustion of coal, which reflect the quality of drilling and blasting operations carried out at the deposit, enrichment and safety of gold and slag waste and fly ash. The article presents the results of studies on establishing the scope of application and evaluating the metrological characteristics of a developed analytical procedure for determination of organic carbon in samples of wastes of mining, processing and combustion of solid mineral fuel using the gravimetric method. The applicability of the procedure for rock samples containing pyrites, as well as the completeness of carbon extraction for coal samples of different degrees of metamorphism (brown, hard and anthracite) were tested using thermogravimetric analysis with mass spectroscopic detection (TGA/MS), which allows conducting a qualitative analysis of volatile substances (water, oxides of sulfur and carbon) released from the analyzed samples under the influence of high temperature. The scope of application and measurement range of the measurement procedure were confirmed by studying real samples of wastes of mining, processing and combustion of coal and specially prepared samples based on sequential ashing of coal samples. The absence of systematic bias in the measurement results according to the measurement procedure was established by analyzing attested samples based on rock samples, a standard sample of rock composition (mudstone) GSO 7223–96 (containing no carbon) and a standard sample of coal composition GSO 10877–2017 (with a specified carbon content) prepared by the addition method and the dilution method. The measurement procedure was certified and assigned registration number FR.1.31.2023.46507 in the Federal Information Fund for Ensuring the Uniformity of Measurements. The prospects for using the measurement procedure to characterize matrix reference materials required for constructing calibration characteristics of express infrared carbon analyzers are considered.

Deep X-ray lithography is often used to produce high-aspect 3D structures. The quality of the structures formed by this method depends not only on the conditions of X-ray transfer of the topology of the pattern formed on the X-ray mask, but also on the conditions of resist development (the solvent used, development modes, etc.). To optimize the matching of conditions, it is also necessary to determine the process window, within which the range of exposure doses and the contrast of the mask are matched with the specific conditions of development of the resist used. The paper presents the results of determining the process window for high-aspect X-ray lithography. The algorithm used is based on the analysis of the behavior of the function of a given ratio of the dissolution rates of the resist under transparent and opaque areas of the lithographic mask (X-ray mask). Two different types of polymethyl methacrylate (PMMA) were used as a resist. The polymerization conditions of PMMA significantly affect its final properties, including its lithographic characteristics. The proposed algorithm assumed the assignment of the ratio of the maximum and minimum rates of development of irradiated PMMA and knowledge of the mathematical formula of the characteristic curve describing the development process in a certain solvent and under specified conditions. It is shown that this algorithm provides experimental repeatability of results and high quality of the formed relief. The obtained results can be used in the manufacture of high-aspect structures from X-ray resist or X-ray-sensitive material (a material whose dissolution rate varies depending on the received exposure dose). In addition, the developed algorithm can be applied to other types of lithographic processes if the formula describing the characteristic curve is known.

Composite materials based on aluminum are widely used in various industries for the manufacture of parts and structural elements. The paper presents the results of diagnostics of the properties of experimental disperse-hardened composite materials (DUCM) based on aluminum obtained by the «internal oxidation method». The interrelated mechanical and technological properties of composites were studied with the identification of a correlation between the parameters of vibroacoustic emission (VAE) and the dynamic method of processing materials in different structural and phase states. Five batches of DUCM castings made using various modes of synthesis of solid phase inclusions in the material matrix were analyzed. The methods and test results for determining the microstructure, chemical composition, hardness of workpieces, dynamic components and the VAE signal during their processing are presented. Differences in the chemical composition of castings have been established by energy and wave dispersion spectrometry. The relationship between the percentage of alloying elements in alloys and the hardness of the workpiece material has not been revealed. At the same time, samples of different melts showed different values of microhardness. The difference in the microhardness of the workpiece materials has little effect on the cutting force and, consequently, on the generated VAE signals. The dependence between the change in the parameter of the VAE signal (RMS value) and the parameter of the processing mode — the cutting speed is established. It is shown that the RMS value of the VAE signal, as an informative parameter, allows us to adequately assess the change in the turning speed of blanks made of DUCM, at which a decrease in the components of the cutting force is observed and the required roughness of the treated surface is achieved. The obtained results can be used to determine the optimal cutting speeds, providing a lower value of the components of the cutting force and a given roughness of the treated surface.

Comprehensive multiscale study of fatigue crack kinetics (FCK) in aircraft engine disks and samples from heat-resistant titanium and nickel alloys is presented. The aim of the studies was to determine the possibility of microfractographic reconstitution and calculated prediction of stable fatigue crack growth based on the measurement and calculation of fatigue striation spacing S. The studies included micro- and macrofractographic measurements of stable crack growth (according to fatigue striation spacing, measured by scanning electron microscopy with high resolution, and to the marker lines determining positions of the crack macrofront after a certain number of loading cycles) and comparing their results, finite element modeling of cracks and calculating the stress intensity factor (SIF) range ΔK, calculated prediction of FCK using kinetic equation S(ΔK), obtained earlier on the basis of physical and mathematical modeling of stable fatigue crack growth mechanism, comparison of prediction results with fractographic data. Because of the study, it is shown that the average value of S characterizes fatigue crack growth rate (FCGR) during the entire stage of stable growth of the fatigue crack, corresponding to the second section of the kinetic diagram «FCGR – SIF range». The use of equation S(ΔK) makes it possible to predict the stable growth of fatigue cracks of different configurations in parts and specimens from structural materials with different crystal structure and microstructure under different loading conditions. The obtained results are of particular importance for ensuring safe operation of high-stress rotary parts of aero engines, in which the duration of stable growth of low cycle fatigue cracks reaches 70 % of the total cyclic life, and fatigue striation spacing is the only measurable characteristic of stable growth rate under service conditions.

As is known, the electroplastic effect (EPE) manifests itself in a decrease in flow stresses and/or an increase in plasticity during metal deformation and simultaneous passage of electric current through it. Of interest is the study of this effect in many metals, including pure titanium, which is biocompatible with an organic environment and corrosion resistant, due to which it is widely used in medicine, aviation engineering and other industries. Traditionally, the effect is studied under tension, and in some cases under other deformation schemes. The objective of this work is to study the features of the deformation behavior of coarse-grained Grade 4 titanium under compression and exposure to pulsed current. When using a high-duty ratio current (Q = 5000), jumps in stress reduction are observed on the compression deformation curve. If a low-duty ratio current (Q = 10) is used in the compression process, the intensity of strain hardening, yield strength, and flow stresses become less than under compression without the effect of current. The microhardness measurements were performed which naturally increases under compression compared to the initial state, while its increase is less intense when using a high-duty current. The structural features of titanium after compression with and without current were studied — the intensity of deformation processes when using current decreases. Under compression refinement of second-phase particles is observed while the effect of current leads to their partial dissolution. A comparison of electroplastic effects under compression and tension has been carried out. Qualitative similarity was noted, but EPE is more pronounced under compression. The results obtained can be used to develop technological processes for electroplastic deformation of titanium.

A mathematical definition of the concept of a «hybrid function of the second kind» (GF2) is given, which differs from a «hybrid function of the first kind» (GF1) in that GF2 completely lacks the connection of arguments of basic functions with arguments of control complexes. Therefore, the number of parameters in GF2 has been increased from three to four. But at the same time, it becomes possible to control GF2 both by a continuous argument and by a discrete one. The possibility of constructing chain functions (CGF2) remains, and any combinations of GF1 and GF2 are possible. The hybrid GF2 function is a function for describing processes that are spaced both in time and space, for example, for studying layered media with different physical and mechanical properties. The article provides an example of a study of the elastic-plastic stress state in a three-layer beam, the layers of which consist of materials with different deformation diagrams. Another example relates to the mathematical modeling of the crack growth process in a flat sample. In this case, the crack growth processes with the corresponding velocities are separated in time. A hybrid function is proposed for modeling the behavior of a complex technical system with negative feedback, which allows to automatically extinguish disturbances arising during the operation of the system.