Direct ICP-AES analysis of petroleum products, organic solvents and fuels is oftentimes possible only in the mode of radial plasma viewing and requires the use of special sample injection systems, the design of which depends significantly on the physical properties of the sample, in particular, on its volatility and viscosity. Volatile oil fractions and products (naphtha, gasoline), as well as and heavy and viscous oil fractions of and petroleum products (vacuum gas oil, fuel oil, thick lubricating oils) are the most problematic objects of analysis. We consider the possibility of direct analysis of the samples based on gasoline, kerosene and lubricating oils dissolved in kerosene using inductively coupled plasma atomic emission spectrometry (ICP-AES). The possibility of using various configurations of sample injection systems and modes of plasma viewing of vertically located torch for direct analysis of the samples based on kerosene and gasoline is considered. A significant improvement in the sensitivity of determination of the elements in gasoline and kerosene using an axial plasma viewing combined with optimal configurations of sample introduction systems and plasma burning modes is demonstrated.

Sultones are cyclic esters of hydroxysulfonic acids, which are formed in the process of sulfonation of α-olefins with sulfur trioxide gas. More stable sultones may be present in the final product — an anionic surfactant — sodium α-olefin sulfonate (AOC-Na). AOC-Na is widely used in the production of household chemicals and cosmetic products, including liquid dishwashing detergents. Sultones are strong skin sensitizers, their level in AOC-Na should be strictly controlled and not exceed 5 ppm. Operational and strict control of the sultone content upon AOC-Na production allows timely adjustment at the stage of hydrolysis, which leads to a more complete disclosure of the sultone cycle with the formation of the corresponding olefin sulfonates and hydroxyalkanesulfonates. We propose a method for determining δ-hexadecansultone in liquid dishwashing detergents and sodium α-olefinsulfonates obtained on the basis of α-olefins of C₁₄ – C₁₆ fractions using GC/MS, which provides shortening of sample preparation and keeps the sensitivity with a detection limit of 0.02 mg/kg. The effect of various weakly polar and non-polar organic solvents used for Sultone extraction from AOC-Na and liquid detergent on liquid extraction based on the dispersion of the extractant in an alcohol/water phase is studied. When selecting the solvent we have shown that the use of diethyl ether provided the best extraction of the analyte. Determination of the analyte extraction recovery was performed using the reaction of hydrolysis of the extracted mixture. We specified the operating mode of the device which provided complete separation of the components of the analyzed compounds including the samples of liquid detergent for dishes being a multicomponent mixture of complex composition.

The possibility of aromatic amine determination using capillary electrophoresis on a «KAPEL-105M» device is studied. Due to their high toxicity, aromatic amines are rated as top- priority environmental pollutants and their content in the atmosphere and water in no way should not exceed MAC. Therefore, improvement and optimization of the instrumental methods of their determination, which can shorten the sample preparation, reduce analysis time, increase accuracy of determination, and also enable automation of analysis becomes an urgent goal of the study. A method for the separation and determination of aromatic amines (aniline, benzidine, 2-aminophenol, 1- and 2-naphthylamines, 2,6-diaminopyridine) by capillary electrophoresis on a «KAPEL-105M» device with a UV detector was developed. We have specified optimal conditions for the determination of aromatic amines (wavelength, pressure, time of sample introduction, voltage) and selected the most suitable electrolyte. The effect of the nature and concentration of the electrolyte on the determination of amines was analized. The developed method exhibited good reproducibility, accuracy, selectivity of determination, and the absence of the interfering influence of the basis of the wastewater sample. The developed method for determination of the aromatic amines was tested on model solutions and real samples of waste water, whereas the correctness of the procedure was proved in spike tests. Direct spectrophotometric detection (λ = 215 nm) revealed the following detection limits: 0.1 mg/dm³ for 1- and 2-naphthylamines, 0.5 mg/dm³ for aniline, 2-aminophenol and benzidine, and 1.0 mg/dm³ — for 2,6-diaminopyridine.

The use of rare earth elements for alloying of aluminum alloys is a promising direction nowadays — filler materials doped with rare earth metals (REM) improve the mechanical properties of welded joints of high-strength aluminum-lithium alloys compared to serial filler material. The results of studying the effect of the composition of alloyed filler materials Sv1209 and Sv1221 and heat treatment mode on the mechanical properties and structure of welded joints of high-strength aluminum-lithium alloys B-1461 and B-1469 are presented. It is shown that the use of filler materials alloyed with rare earth metals in combination with full heat treatment (quenching and artificial aging) carried out after welding provide an increase in the strength characteristics of the welded joint to the level of strength of the base material with sufficiently high ductility and toughness. Metallographic study of welded joints after heat treatment revealed a fine-grained structure in the center of welds attributed to alloying of the filler with REM. Transmission electron microscopy is used to study precipitated hardening phases in welded joints. The round-shaped phase Al₃(Sc, Zr) and a fine δ’-phase precipitated upon cooling of the welded joint are present in weld adjacent zone of V-1469 alloy. At the same time, artificial aging after welding results in formation of copper-containing Ω’- and θ’-phases. Quenching and artificial aging of the welded joint resulted in an increase in the size of precipitated hardening T₁’-, S’-, θ’-phases and density of their distribution in the grain volume in the heat-affected zone of V-1461 alloy. Thus, heating upon welding leads to uneven phase precipitation, whereas additional artificial aging aggravates the non-uniformity of decomposition through partial dissolution of some phases and coarsening of the other.

The results of studying the structure of the coating obtained by «freezing-out» method with a preliminary surface preparation including application of the underlayer or precoat by cladding with a flexible tool (CFT) are presented. The CFT procedure consists in coating with a rotating cylindrical metal brush. The developed technology of coating using «freezing-out» with the preliminary application of the precoat makes it possible to exclude harmful and labor-consuming galvanic operations. The effect of technological parameters on the quality of CFT-formed coating, i.e., the structure of the interface between the steel-copper system and data of durometric measurements of the microhardness of the copper layer and the steel core were analyzed. Elastic-stress states in the surface layer of the core and in the copper coating were determined using X-ray tensometry by the method of oblique survey. The effect of the underlayer of various materials (copper, brass, tin, tin-lead alloy) on the adhesion of the main copper coating to the core after «freezing-out» copper was studied using an adhesimeter. A fractographic analysis of the destroyed coating surfaces was also carried out. The distribution of metals in the border zones of the steel-copper compound is determined. Camscan scanning electron microscope and X-ray microanalyzer Link exL are used to examine the zone structure for the presence of intermetallic compounds. The developed «freezing-out» procedure with a preliminary application of the undercoat by CFT method is environmentally friendly, easy to use and low-power-consuming technology.

The special features of various bearing deformation measurements for pin-type bearing tests of metallic materials are considered along with their impact on the magnitude of the «bearing elastic modulus» and bearing stress. These bearing test methods are present in ASTM and various institutional standards, though no state standard (GOST, GOST R) is currently available for bearing test method of metallic materials. Analysis of additional deformations which arise in determining the degree of hole bearing deformation is carried out. A set of sources of additional deformations is shown to be characteristic for each test procedure and is attributed to the design features of the device, the site and a way of mounting the extensometer. Additional deformations can be both tensile and compressive. It is shown that the impact of additional deformations on the «bearing elastic modulus» is limited to 14% for different procedures. No difference between the methods is revealed with regard to determination of the strength characteristics. At the same time the dispersion decreases with increase in plastic deformation and for bearing deformation about 4% the variation coefficient for all methods is no more than 1%. Advantages and shortcomings of the bearing test methods which affect the reproducibility of the results are considered. The effect of the specimen geometry on the bearing characteristics is considered. It is shown that increase both in the distance from the edge of the bearing specimen to the center of the hole for 1163T, VT6ch, 30KhGSA alloys and residual bearing deformation up to 6%, increase bearing strength characteristics.

The results of experimental studies of the static strength, fatigue and crack resistance of modern improved aluminum alloys 1163ATV, 1163RDTV, 1441RT1, 1163T, 1163T7, 1161T, V95ochT2, B96-3pchT12., 1973T2 developed at the All-Russian Scientific Research Institute for Aviation Materials (VIAM, Russia); and 2524-T3, 6013-T6 HDT, 2324-T39, C433-T351, 7055-T7751 developed at ALCOA (USA) are presented. Those materials are used in the construction of modern operated and designed aircraft. The experimental data were obtained in testing standard specimens on electro-hydraulic machines MTS (USA), Instron (Great Britain) and Schenk (FRG). The tested specimens were cut from semi-products manufactured according to serial technologies. The mechanical properties of materials under tension (σ_b, σ_0.2, δ), fatigue characteristics, fatigue crack growth rate, stress crack propagation curves under static loading (R-curves), conditionally critical stress intensity factors are determined according to domestic standards. To ensure high weight efficiency combined with a high resource and high performance characteristics of the aircraft structures, aluminum alloys must have the following set of necessary characteristics: high resistance to variable loads, low rate of fatigue cracks growth, required residual strength, and good corrosion resistance. The obtained results of experimental studies clearly demonstrate the advantages and disadvantages of the strength properties of the materials under study. The results of experimental studies provide the possibility to compare the strength properties of the materials under study to optimize their use for the specific zone of the structure and thus increase the life and safety of the aircraft design.

Results of the experimental study of the effect of preliminary thermomechanical impact (TMI) via thermal cycling under load on the deformations attributed to the shape memory effect (SME) are presented. Two modes of TMA were studied: i) thermal cycling under constant loads, the values of which were sequentially increased to the level of the maximum value; and ii) thermal cycling under constant loads, the values of which are successively reduced from the level of the maximum value to zero. Smooth cylindrical samples with a length and diameter of the working part 33 and 4 mm, respectively, made of TN-1 alloy with characteristic martensitic transition temperatures were used. The experiments were carried out in the mode of thermal cycling through the intervals of martensitic transitions at a constant value of torque. It is shown that thermocycling in conditions of mode (i) leads to a monotonic growth of the SME induced deformations, whereas subsequent thermocycling at the same load in conditions of mode (ii) leads to a noticeable increase in the SME induced deformations. A logistic model of the phenomena of martensite inelasticity observed in the materials with shape memory effect is proposed on the base of the Verhulst logistic equation which provides a fairly accurate description of the material deformation during all the stages of thermal cycling. A computational-experimental method has been developed to take into account the effect of a preliminary thermomechanical impact on SME induced deformations.

Theoretical and practical issues of processing digital information in the problems related to durability assessment in conditions of loading are considered. Due to the specifics of the problem, in which the precise dedermination of the extreme values and their sequence is of primary importance, a number of generally accepted recommendations appeared invalid. For example, the Kotelnikov theorem, which was originally proposed in relation to the problems of estimating the frequency composition of the process, can lead to significant errors. It is shown that the requirements to the analysis of random loading processes with a goal of further assessment of the durability, due to their specificity, contradict with the specified requirements, namely, when choosing a frequency according to this rule, an error can be made, and not to the margin of the strength assessment. We considered the issue regarding digital filtering of hardware overshoots. Alternative approaches to the selection of extrema of the random process are analyzed: 1) direct hardware selection of extrema and 2) discretization by the method of level crossings. The latter approach has an optimal algorithm for isolating extremes and makes it possible to isolate extremes of a random process with lower costs and greater accuracy. The natural transition to integer arithmetic provides further optimization of the algorithm. The model and real examples demonstrate gains in terms of speed and memory, which ultimately promote an increase in the reliability of the information required for assessing the durability. The savings in memory and performance will allow processing of long-term implementations and result in a more accurate estimating of the remaining life and durability at the stage of production.

The issues of organizing an expert survey and carrying out statistical processing and analysis of the results are considered. The experts are the fifth-year students undergoing training at the Department of Management and Informatics «Moscow Power Engineering Institute» of the National Research University. The goal of the survey is revealing the disciplines that are most useful for employment in their specialty. We discuss the special features of the survey and a concept of «work in the specialty», with due regard for statistical reliability of the results. Data of written questionnaire gained in 2018 were processed and analyzed using cluster analysis (construction of dendrograms and application of the K-means method) and non-parametric statistical criteria (Friedman and Mann – Whitney – Wilcoxon). Data processing is implemented in the program STATISTICA. The analysis is carried out to reveal significant differences between the educational courses and assess the degree of consistency of the respondents to divide them into clusters that unite the students with similar judgments. Data analysis revealed that experts’ estimates in 2018 are in fairly good agreement with the estimates of previous studies; among the respondents there are three coalitions corresponding to the training modules «Software», «Management Theory», «Data Analysis»; the overall consistency of students in the two groups is very low (and, on the contrary, high in the identified clusters); grades are homogeneous and do not depend on training groups (and employment – unemployment of the respondents). The obtained results allow us to address a number of important questions regarding the ways of improving the educational process, e.g., to optimize yearly course hours for different educational modules.