An experimental prototype of a new spectral excitation source based on microwave induced plasma with an excitation field frequency of 915 MHz and a power of up to 3000 W has been created. The plasma in this source is excited by an H₀₁₁ wave in a cylindrical microwave resonator with a dielectric element installed inside and has a shape and dimensions close to those of an argon ICP. Compared to a traditional microwave plasma with an excitation frequency of 2450 MHz, the temperature of the resulting plasma is 300 K higher and amounts to approximately 5500 K. It has been shown that the intensities of analyte lines are 2 – 5 times higher compared to traditional MIP sources with a frequency of 2450 MHz, and the detection limits for most elements are lower. The influence of matrix elements on the magnitude of the analytical signal has been studied using Mg, Ca, K, and Na as examples. The matrix influence of the spectral excitation source with MIP (915 MHz) is similar to that of MIP (2450 MHz) and increases in the following order: Mg < Ca < K < Na. When 0.5% Na was introduced into the MIP (2450 MHz), the plasma was quenched. For the MIP (915 MHz), the matrix effect was less pronounced: for lines with energies >8 eV, the introduction of a 0.5% K solution reduced the analyte intensity by a factor of 5, while for the MIP (2450 MHz), it decreased by a factor of 10. The relative standard deviation was approximately 3% over 3 h of measurement. Despite some improvement in the performance of the new spectral excitation source with a plasma excitation frequency of 915 MHz, this is clearly insufficient to replace the traditional MIP source with an excitation frequency of 2450 MHz in commercial spectrometers.

Paclitaxel (PTX) is a cytotoxic antitumor agent from the taxane group, which low bioavailability and tissue biodistribution can be altered in the presence of inhibitors of liver enzymes and transport proteins. One of them is ritonavir (RTV), an antiretroviral agent used in the treatment of HIV infection. This study describes the development and validation of high-performance liquid chromatography with photodiode-array detection (HPLC-PDA) method for the simultaneous quantitative determination of PTX and RTV in rat blood plasma, liver, brain, and testis homogenates. Sample preparation involved liquid-liquid extraction followed by extract evaporation, redispersion in the mobile phase, and additional purification. Analytes were separated using LC-2030C 3D Plus Prominence-i system (Shimadzu) under reversed-phase chromatography conditions with an isocratic elution mode. The separation was performed on Hawach C18 Universal column (250 × 4.6 mm, 5 μm particle size). The mobile phase consisted of water (A) and acetonitrile (B) in a 50:50 ratio. Detection was carried out at the following wavelengths: for PTX 228 nm (retention time: 16 min), for RTV 240 nm (retention time: 19 min). The method demonstrated linearity over the concentration ranges of 100 – 9090 ng/mL PTX for plasma and 25 – 9090 ng/g for tissues, 250 – 9090 ng/g RTV in all matrices. The LOQs were 100 ng/mL PTX and 250 ng/mL RTV in plasma; 25 ng/g PTX and 250 ng/g RTV in tissues. The developed method exhibited high accuracy (relative error Δ < 12%) and precision (relative standard deviation RSD < 14%) across the entire concentration range. The recoveries for both PTX and RTV exceeded 80% in all biological matrices. In this regard, the method can be used to study the pharmacokinetics of this combination of drugs in biological matrices.

A simple, rapid spectrophotometric method for determination of Cu (II) ions is described using a new analytical reagent — [(2-hydroxybenzaldehyde)-3-isatin]-bishydrazone (R), which is a product obtained by condensation of salicylic aldehyde with isatin hydrazone. NMR spectroscopy and X-ray diffraction analysis were used to confirm the composition and structure of the synthesized reagent. Complexation of Cu (II) with R in the presence of diantipyrylphenylmethane (DAPM) and 8-oxyquinoline (Ox) was also studied spectrophotometrically. Optimum conditions for complexation (λ_opt, pH_opt) of homogeneous (Cu (II)-R) and mixed-ligand (Cu (II)-R-Ox and Cu (II)-R-DAPM) complexes were determined. The molar absorption coefficients of the complexes and the region of subordination to Beer’s law were established. The stoichiometric ratio of the components in the complexes was confirmed by the methods of isomolar series, continuous changes (Job’s method), and equilibrium shift. The effect of some foreign ions and masking substances on the formation of Cu (II) complexes was studied. The proposed method was used to determine trace amounts of copper in various vegetable samples (pepper, onion and cabbage).

The accuracy of mechanical stress monitoring in steel structures using magnetic methods is affected by the spread of the magnetoelastic properties of the material, which is related to its chemical composition, manufacturing technology, and heat treatment regime. The objective of this study was to monitor axial tensile stresses in steel using magnetoelastic demagnetization. Tests were conducted taking into account the magnetoelastic sensitivity of the material, which was determined under additional transverse compression. The working axial tensile stresses of the bottom flanges of I-beams made of 15KhSND steel were evaluated. The magnetoelastic memory of the flanges and plate steel specimens under axial tension and local transverse compression was analyzed. It was found that the relative change in the stray magnetic field strength of the local residual magnetization of the studied beams and specimens is directly proportional to tensile and transverse compressive stresses. It was shown that the magnetoelastic sensitivity of the analyzed steel grades to tensile and compressive stresses, determined by the slope of the identified dependencies, differs by 10 – 20%. The obtained results can be used to improve the methodology for monitoring the technical condition of operated steel structures.

With the development of small-scale energy and decentralized energy supply, there is a growing interest in energy supply schemes based on solid oxide fuel cells (SOFC). The purpose of the work is to study the effect of the formed catalytic layer on the electrodes of the SOFC on the electrochemical characteristics of the elements. Vertically aligment of carbon nanotubes (CNT) were used to create the layer, on the surface of which the catalyst material was uniformly sprayed. It is shown that a significant increase in the active surface area of the catalyst due to the layer formed in this way contributes to a significant acceleration of electrochemical processes at the three-phase boundary of the reaction zone in the SOFC. As a result, the power of the fuel cells increases. In addition, due to the increased chemical resistance, effective heat dissipation and structural strength of vertically aligment CNT, the service life of the SOFC increases. A method and an automated system for monitoring and creating a catalytic layer on SOFC electrodes are proposed. The conducted studies have confirmed a significant increase in the specific power and the number of on/off cycles of fuel cells without loss of power compared to cells obtained by traditional methods. The results obtained can be used for the development of energy technologies, primarily in the field of alternative energy sources, and the improvement of solid-state power plants.

Non-uniform densification of green compacts, sample warping, and deformation during sintering influence the final shrinkage of specimens, potentially leading to erroneous interpretation of sintering outcomes. The objective of this study was to investigate densification and creep behavior during the sintering of ceramics fabricated from submicron α-Al₂O₃ powder admixed with 0.25 wt. % MgO. Dilatometric techniques were employed to evaluate the development of shrinkage anisotropy in specimens subjected to increasing applied loads during sintering. Results demonstrate that, under low applied stresses (below the sintering stress), specimen densification remains independent of the imposed load. Creep rates increase with elevated applied stress, reduced initial green density, and extended isothermal holding times. Analysis of dilatometric shrinkage data for aluminum oxide specimens enables the decoupling of densification and creep contributions, thereby elucidating the effects of initial green density and sintering parameters. No grain growth was observed in the examined specimens at relative densities below 90% of theoretical. The observed exponential decline in average creep rate with increasing density is attributable to the pronounced grain size dependence of diffusional creep. The analogous response of densification and creep rates to variations in specimen density suggests that both processes are governed by identical mass transport mechanisms. The ratio of densification rate to creep rate was found to be proportional to the sintering stress and only weakly dependent on temperature. This ratio increases with specimen density. The findings offer valuable insights for refining sintering protocols and accurately assessing ceramic densification under constant heating rate regimes and isothermal holds.

The application of instrumental indentation method with the Berkovich pyramid for determination of the microhardness and radiation hardening of steels after ion irradiation is considered. The main difficulties arising in microhardness determination of a thin irradiated layer are identified. First of all, such difficulties arise when microhardness is determined with indentation diagram and the Oliver and Pharr formulae. For this case the dependence of microhardness on the indentation depth is observed even for homogeneous material. Disadvantages of microhardness determination are considered when the combine approach is used that includes processing indentation diagram with the Oliver and Pharr formulae and processing dependence of microhardness on indentation depth by the Nix and Gao diagram. A method for determining microhardness based on direct measurement of the indent projection area is proposed, which allows eliminating the influence of indentation depth on microhardness for a homogeneous material. It is shown that for a homogeneous material, the microhardness under indentation with both the Berkovich and Vickers pyramids does not depend on the indentation depth if the area of the indent projection is determined directly by measurement of its geometric characteristics. The method proposed in the work allows obtaining adequate estimates of radiation hardening of a thin layer of material irradiated by ions. The method has been verified by indentation at constant strain rate for two classes of steel: austenitic and ferritic-martensitic.

The article presents the results of tensile and compressive tests of modern antifriction materials for highly loaded friction units at temperatures ranging from 80 to 180°C, aimed at evaluating their applicability in sliding bearings operating under elevated temperature conditions. The tests were conducted in accordance with methods regulated by GOST standards. A comparative assessment was performed of the mechanical properties of polymer-based antifriction materials (PCM) based on polyetheretherketone and babbitt alloys grades B83 and B16 (GOST 1320–74, ISO 4383–91), as well as the TEGOSTAR 738 alloy analogue. The test results revealed fundamentally different strength mechanisms in PCMs and babbitts, as well as differences in their behavior with increasing temperature. PFMs demonstrate significantly higher values of tensile strength, compressive strength, and yield strength compared to babbitt alloys. Babbitts exhibit pronounced plastic behavior already at 80°C, with a distinct yield stage; however, their strength sharply decreases above 100°C, approaching the yield limit, which limits their load-bearing capacity under heated conditions. Although babbitts’ plasticity helps absorb impact loads, it also contributes to frequent failures of babbitt-layered bearings. At temperatures above 120°C, babbitts undergo significant thermal degradation caused by softening of eutectic structures and microstructural deterioration, while reinforced PCMs maintain stable mechanical properties due to the heat resistance of the polymer matrix and effective load distribution through the reinforcing phase. The possibility of tuning PCM properties by selecting matrices, fillers, and additives was noted, opening prospects for adapting materials to specific operating conditions. The combination of lower plastic deformability and high strength gives PCMs better shape retention and stability during failure, while their high thermal stability allows their use over a wider temperature range compared to babbitts. It was confirmed that the imported babbitt TEGOSTAR 738 does not possess significant advantages over domestic grades such as B83, making imported materials economically unjustified. Meanwhile, PCMs outperform babbitts in strength and thermal resistance, enabling an increase in bearing operating temperatures above 200°C while maintaining performance. This opens prospects for using PCMs in modern rotary systems with high reliability requirements. The results confirm the superior mechanical characteristics of PCMs available on the Russian market and the prospects for their application in highly loaded sliding bearings. Further research is recommended to expand testing, including tribological properties and a wider range of materials. The findings can be used by designers and engineering personnel to broaden the range of bearing materials in the design and modernization of highly loaded friction units of rotary equipment to meet modern demands for load capacity, temperature regime, and reliability.

The intensive development of Arctic resources and the expansion of shipping in icy conditions require the use of structural materials with increased operational reliability. The objective of this study was to investigate ice adhesion to high-strength steels under conditions as close as possible to Arctic conditions. Testing utilized modeling of uniform compression during freezing and an environment simulating seawater. High-strength steels with yield strengths of 540 and 760 MPa were studied. The developed original testing methodology utilized blade-type specimens and specialized tooling for universal tensile testing machines, ensuring the accessibility and versatility of the approach. The methodology involved freezing the specimens in synthetic seawater at temperatures ranging from –10 to –30°C, creating combined loading conditions combining shear and direct tensile stress. Thorough surface degreasing was shown to be a key factor in data reproducibility (untreated specimens demonstrated an uncontrolled decline in adhesion). An analysis of load-elongation diagrams revealed the characteristics of adhesive bond failure and subsequent friction during sample removal. The results and proposed approach can be used in comparative analysis of various steel grades and anti-icing coatings, as well as in selecting materials for the safe operation of infrastructure and equipment in the harsh climatic conditions of the North.

The article outlines the conceptual foundations of a unified system-synergetic theory of information, which represents a significant step forward compared to classical approaches. This theory is the result of a formal synthesis of two leading Russian scientific schools: the synergetic theory of information, which describes information through the prism of dynamic self-organization processes, and the systems theory of information, which defines information through the structural-hierarchical and emergent properties of systems. Unlike classical theory, which views information as a measure of diversity within a set of unrelated elements, the proposed approach introduces the concept of a «system», where interconnections between elements play a pivotal role. This allows for the quantitative measurement of such previously purely qualitative concepts as complexity and emergence. The central result of the theory is the formulation of the universal information variational principle. This principle postulates that the development of any open system — from physical and biological to economic and social — occurs in such a way as to maximize the rate of information increment. It is proposed that this principle be viewed as one of the key regularities of evolution, determining the direction of system development toward increasing complexity and order. The theory offers specific metrics for measuring systemicity and complexity, such as the coefficient of emergence, which indicates how many times the information capacity of a system exceeds the information capacity of a simple set of its elements. In conclusion, this work offers an approach to overcoming a number of limitations inherent in classical information theory and formulates a fruitful program for future research. It opens new horizons for understanding and modeling complex systems by offering a unified explanatory mechanism for a wide range of phenomena. Practical applications of the theory include the development of new methods for big data analysis, the creation of more adaptive and self-learning artificial intelligence systems, and the forecasting of market and social network development. Thus, the proposed theory lays the foundations for the creation of a unified science of complexity, uniting the efforts of scientists from various fields.