This paper presents a new approach to studying diclofenac (DCL) peroxidation products and their reactivity, based on a combination of LDI target surface functionalization and modeling of the electro-Fenton reaction under microdispersed electrospray (MED) conditions. To ensure active interaction of diclofenac molecules with hydroxyl groups, peroxidation was carried in the presence of Cu+ ions, which promoted the formation of hydroxyl radicals. The peroxidation products and their adducts with glutathione were determined using SALDI/MALDI mass spectrometry. This study demonstrated that the use of a microdisperse electrospray system in combination with peroxidation enables the efficient isolation of diclofenac metabolites from the first and second stages. SALDI and MALDI analysis of diclofenac peroxidation products revealed new oxidative transformation products and glutathione adducts. The use of a microdisperse electrospray system significantly accelerated the modeling of oxidation processes compared to traditional methods, allowing the deposition and recording of the resulting products in the presence of titanium dioxide nanoparticles on the surface of an LDI target in parallel with oxidation reactions. In this case, the deposited particles serve as ion emitters for SALDI-MS analysis. The obtained results open new horizons for faster and more accurate analysis of drug biotransformation products. The development and implementation of this approach can significantly accelerate the process of assessing the toxicity of pharmaceuticals.

Volatile organic compounds (VOCs) in the vapor phase above an industrial sample of sodium polyacrylate were investigated under various temperature conditions using gas chromatography-mass spectrometry combined with headspace analysis (HS-GC-MS), with the aim of identifying impurities and thermal degradation products. Conditions ensuring effective chromatographic separation of the degradation products mixture with acceptable resolution of major and minor component peaks were proposed. The sodium polyacrylate samples were thermostated at temperatures simulating operational (30 and 60°C) and extreme technological (190°C) conditions, both with and without air purging. The absence of VOCs in the original industrial sample after thermostating at temperatures up to 60°C was established. At 190°C, nine thermal degradation products and impurities were identified for the first time in the vapor phase, including propylene glycol, 1,4-butanediol, nonanal, dimethyl glutarate, alkyl acetals, bicyclic terpenes (cedrene, longifolene), and 2,6-di-tert-butylquinone (antioxidant degradation product). It was demonstrated that short-term purging of the sample with air at 190°C leads to a significant (by an order of magnitude) reduction in the concentrations of all identified VOCs. Based on an analysis of published toxicological data, it was concluded that the identified VOCs pose a low inhalation risk. The obtained results are important for developing safety measures for the high-temperature processing of sodium polyacrylate and confirm its status as a low-hazard material.

The applicability of the Olympus Vanta M X-ray fluorescence analyzer to obtain quantitative data on the elemental composition of archaeological ceramics was evaluated. Fragments of ceramic vessels from collections of 7 archaeological sites dating from the early to late Neolithic (~8.5 – 5 thousand years ago) were selected as a case study. To assess the trueness of the portable instrument’s analytical results, reference materials of sedimentary rocks with a close to the studied ceramics composition were used. For most of the analytes (Al, Si, P, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Rb, Sr, Y, Zr, Ba, Pb), linear correlation between the determined and certified concentrations was observed (R² ≥ 0.90), which allowed us to conclude that the built-in (factory) calibration for these elements is reliable. Measurements of the outer and inner surfaces, as well as cut of the sherds without destruction, showed heterogeneity in the P, Ca, Mn, Cr, Ni, Cu, and Zn distribution within a ceramic fragment. Homogeneous distribution in different parts of the sherd was observed for Al, Si, K, Ti, Fe, Rb, Sr, Y, Zr, Ba, and Pb. For these elements, the relative discrepancies between the results obtained by the Olympus Vanta M analyzer for sherds and by the reference methods for powdered ceramics did not exceed 30%.

The main parameter used to characterize the resistance of materials to corrosion is the corrosion rate, which is estimated by the amount of deterioration over a certain time, while the average value is presented on an arbitrarily selected test base. However, current corrosion rate measurement methods do not adequately capture the kinetics of corrosion development, hindering the ability to predict the lifespan and serviceability of components. The results of determining the corrosion rate of carbon dioxide by the concentration of iron ions in the test environment are presented in the paper. During the corrosion tests, the concentration of iron transferred to the test environment was measured, and the rate of corrosion destruction was determined based on data on iron loss. The influence of test temperature, composition, and structural condition of pipe steels on the kinetics of carbon dioxide corrosion development was also analyzed. The dependences of the change of corrosion rate and the development of corrosion processes are given. It is shown that the average corrosion rates values during long-term tests correlate well with results from gravimetric and electrochemical methods. The results obtained and the proposed approach can be used to improve methods for determining and evaluating the dynamics of changes in the rate of corrosion during exposure to a corrosion environment.

High-entropy alloys (HEAs) are a new class of materials for which powder metallurgy methods (coating deposition, additive manufacturing, free sintering) are the most promising for obtaining a homogeneous structure throughout the volume of large-sized products due to the complexity of their fabrication. This paper presents the results of a study on the structure and mechanical properties of an Al – Ni – Co – Fe – Cr HEA system using the nanoindentation method. The phase composition, morphology, and mechanical characteristics of an HEA coating formed by microplasma spraying were analyzed. The structural constituents of the coating were determined by X-ray diffractometry. The hardness within each structural constituent was evaluated under a load of 5 mN. X-ray structural analysis revealed the presence of solid solutions based on BCC and FCC lattices and an intermetallic compound with parameters close to those of AlNi. Furthermore, an additional oxide phase with a high content of Al and Cr, presumably of the spinel-type AB2O4 (A = Ni/Co/Fe, B = Al/Cr), was identified. Approximately 61% of the area is occupied by a structural constituent with a nanohardness of 10.2 GPa and a Young’s modulus of 166 GPa. The obtained results can be used in the development and improvement of wear-resistant, dispersion-strengthened microplasma coatings based on HEAs.

The aim of this study is to develop an acoustic emission (AE) monitoring methodology that is invariant to the mechanical impact influence. To achieve this objective, regression and statistical analysis algorithms were employed to identify nonlinear relationships between the degree of damage in composite specimens (j) and the values of streaming AE parameters. As the most informative AE parameters correlating with the actual condition of the monitored specimens, the quantile values at the p = 0.9 level of the distribution functions of the front energy ([Eφ]p = 0.9) and specific energy ([EN]p = 0.9) of AE pulses were selected. A key stage in the implementation of the proposed methodology involves partitioning the criterion plane ([EN]p = 0.9 – [Eφ]p = 0.9) into three characteristic segments (I, II, III). Based on the values of the streaming parameters and their weighted distribution across segments I, II, and III (WI, WII, WIII), a regression model was synthesized to assess the degree of damage in composite specimens using AE monitoring results. The maximum reduced error of the developed model was γ = 9.8%, while the mean relative error did not exceed 1.1%, regardless of the initial condition of the monitored specimens.

When manufacturing parts of complex geometry using additive technologies, anisotropy of mechanical properties occurs in materials. The assessment of the anisotropy of static and cyclic properties is carried out, among other things, using experimental studies on samples cut in different directions from the deposited billet. The purpose of the work is to study the anisotropy of mechanical characteristics under cyclic and static loads of 316LSi stainless steel obtained by wire-arc welding. The tests were carried out on samples cut in three different directions from the deposited billet under static tension. It has been established that the elastic properties of steel are primarily influenced by the direction of sample cutting. The effect of sample orientation on the mechanical behavior of steel under low-cycle fatigue with controlled axial deformation parameters is analyzed. It is shown that the samples cut in the vertical and diagonal directions with respect to the plane of the deposited layers have the highest and lowest cyclic durability with equal values of the amplitude of deformation. The results of comparing experimental low-cycle fatigue curves with curves whose parameters were calculated based on the Basquin – Manson – Coffin equation and data from static tensile tests are presented. The possibility of predicting the characteristics of low-cycle fatigue for different directions of sample cutting is shown. The results obtained can be used to modify the technological parameters of wire-arc surfacing to reduce the effect of anisotropy of the mechanical properties of additive materials.

Many factors (the method of manufacturing the material, the number and thickness of the layers, the pattern of alternating layers) influence on forming and destruction of multilayer materials. The purpose of the work is to evaluate the effect of the thickness of the torn part on the total thickness of the sample on the stress-strain state at the interlayer boundaries of a layered metal composite material based on 09G2S and 12Kh18N10T steels. The debonding process is implemented using finite element modeling in conjunction with the virtual crack closure (VCCT) method. A series of computational experiments has been implemented with varying the critical rate of elastic energy release under conditions of separation of two samples with different ratios of the thickness of the torn part to the total thickness of the sample. As a result of a series of computational experiments, the stress state along the junction boundary was determined. The stratification will begin when the criterion for the critical rate of release of elastic energy GIS is below 40 kJ/m2. The stratification begins to form in different places, depending on the ratio of the thickness of the torn part to the total thickness of the samples under study. The deviation of the maximum main stress at the crack tip from the direction of application of the load is 10°. It is more preferable to use a sample where the ratio of the thickness of the torn part to the total thickness of the sample is less. The results obtained can be used in selecting the geometry of the sample for stratification tests and evaluating the quality of the joint layers.

Every year we see an increase in the requirements for the efficiency of both newly created and existing systems. This leads to a complication of the tasks to be solved when creating, diagnosing, and managing these systems and phenomena. One of these tasks is to determine the nature and structure of relationships between ongoing processes. These processes are stochastic in nature, and they are usually described by correlation dependencies. However, their multidimensionality and multiple connectivity make it difficult to apply correlation analysis. For a clearer understanding and use of correlation dependencies, their systematic interpretation is necessary. A fundamental characteristic of any system with ambiguous or probabilistic behavior is entropy. Specifically, several results have been obtained linking the differential entropy of random vectors with correlation characteristics. The purpose of the article is to investigate and systematize the relationship between differential entropy and correlation indicators used in multidimensional statistical analysis. The article considers all the main variants of correlations in multidimensional systems, including the cross correlation between all elements, between subsystems, at different levels of the system, between one element (subsystem) and a group of elements (subsystems). In all cases, it has been established that correlation indices are analytically determined from the differential entropy of a system considered in the form of a random vector. Several examples have been given to illustrate the results obtained.