Precise determination of the isotope masses of superheavy elements obtained by the complete fusion of ⁴⁸Ca⁺ ions with Au, Pb, Bi, U, and Pu targets can provide valuable information on the mechanisms of nuclear reactions leading to the formation of these elements. A specialized multi-turn time-of-flight mass spectrometer is to be used to match the goal. The source of the target isotopes is a DC-280 cyclotron, a «factory of superheavy elements» at the Joint Institute for Nuclear Research (JINR, Dubna, Russia). The point of the problem is that ions of superheavy elements are formed quite rarely even in the specialized accelerator of JINR: during the last experiment, the frequency of their appearance was up to 10 events per day. Precise determination of the mass number requires comparing the time of flight of a superheavy ion through a mass analyzer with the same time for a calibrant ion, the mass number and charge of which are precisely known a priori from the process of its formation. Implementation of such a mass spectrometric analysis required the development of an ion source capable of stable operation for a long time. To solve the problem, a number of ion sources were considered. The choice of an ion source with electron ionization is substantiated. A source with a crucible in which the calibrant evaporates during heating was proposed and tested. Various substances (PbBr₂, Nd, C60, fullerene soot) were considered as a calibrant. The mass spectra of these compounds are presented, namely, the spectrum of neodymium compounds and the mass spectrum of fullerene soot. It is shown that the use of fullerene soot is optimal, since the mass spectrum of fullerene soot contains ions in the range of mass numbers from 12 to 800 and higher. Moreover, the mass spectrum of fullerene soot contains many peaks in the mass number region of interest 275 – 300 a.m.u. It has been experimentally shown that the ion intensities within the indicated range differ by less than an order of magnitude which makes the use of fullerene soot a standard sample for calibration of a high-resolution time-of-flight mass spectrometer.

A comparative evaluation of the effectiveness of the industrially produced oil spill dispersants (Finasol OSR 52 (France), Slickgone NS and Slickgone EW (United Kingdom)) was carried out. The effectiveness of dispersants was assessed using three samples of domestic crude oil with different physical and chemical properties (extra light, heavy, and bituminous oil) in water samples of various salinity. An adapted version of ASTM F2059–17 «Standard Test Method for Laboratory Oil Spill Dispersant Effectiveness Using the Swirling Flask» (the so-called SFT test) was used for evaluation. The low-energy technique was chosen to determine conditionally lower limits of the dispersant effectiveness. Comparative tests were carried out at the highest dispersant-to-oil ratio 1:10 allowed in the Russian Federation (according to STO 318.4.02–2005 «Rules of dispersant application for oil spill response»), water temperature 20°C and water salinity 0, 5, 10, 20, and 35‰. It is shown that the dispersants are poorly effective in dispersing the considered oil samples at water salinity 35‰. A general trend of increasing the dispersant effectiveness with a decrease in water salinity is demonstrated. It is shown that all tested dispersants are not suitable for application in the studied range of water salinity in the event of spill of the bituminous oil with a high content of asphaltenes and polar compounds. For all dispersants, the limits of their application are determined depending on the salinity of water. The effectiveness value equal to 45 % legally approved in the USA and Mexico was taken as a threshold value. The revealed lack of the dispersant versality necessitates preliminary experimental testing using a sample of spilled oil under climatic and hydrochemical conditions corresponding to the potential area of their application.

Methods of gas chromatographic determination of trace amounts of sarin and soman in industrial emissions at a level of 1.0 × 10^–6 mg/m³ have been developed. The capture and concentration of the target analyte was carried out using a specially designed sampling fluoroplastic cartridge filled with a pre-prepared sorbent Tenax TA with a grain size of 60/80 mesh and a volume of 8 cm^3. The extraction of concentrated substances from the sampling cartridge was carried out using a modified and improved method of thermal desorption which consists in involving hot vapors of the solvent (resulted from the introduction of a liquid solvent into the cavity of the sampling cartridge with subsequent heating to 200°C) into desorption process in addition to the inert carrier gas. The substantially higher efficiency of the modified method of thermal desorption compared to the classical methods of extracting target substances from sorbents has been experimentally proved. Data on the quantitative content of sarin and soman were obtained by gas chromatographic method using a Varian CP-3800 gas chromatograph equipped with a pulsating flame-photometric detector, the mixture was separated on a VF-5ms capillary column. The sensitivity of a classical flame photometric detector and a pulsed flame photometric detector to sarin and soman has been studied. The developed methods have a relative error of determination about 27 %, and the duration of analysis of one sample is 3 h 30 min. The methods were tested on the real objects of control, appropriately certified and implemented in practice.

Nowadays, the transition from shaped casting to the methods of selective laser sintering and selective electron beam sintering (SELS) has been implemented for a number of materials. The thermophysical properties of materials play a decisive role when designing and modeling heat and mass transfer processes during powder sintering by additive technologies and monitoring the stability of the operational properties of final products. We present the results of studying the thermophysical properties of the samples of heat-resistant intermetallic titanium γ-alloy obtained by shaped casting and SELS in the range of 200 – 900°C. The characteristic DSC curves of the images and experimental temperature dependences of the heat capacity and thermal conductivity are presented. Comparative analysis of sample density measurements was carried out before and after thermal exposure. Analysis of the results obtained revealed a similar nature of the temperature dependences of the specific heat capacity and thermal conductivity of the samples produced by the methods of shaped casting and SELS. The presence of thermal stresses was observed when measuring the thermal expansion coefficient in the samples obtained by shaped casting. However, leveling of the stress state by additional thermal exposure led to identical values of the thermal expansion coefficient for the samples obtained by both methods. The results obtained can be used to improve the methodology for modeling heat and mass transfer processes during sintering of metal-powder compositions.

The internal carbon dioxide corrosion is one of the most common types of corrosion in the gas fields development. The results of studying the composition of carbon dioxide corrosion products by X-ray diffraction method are presented. FeCO₃ is the main product resulting from dissolution of steel upon carbon dioxide corrosion. Siderite is characterized by the phenomenon of isomorphism in the crystal structure (a change in the chemical composition of the phase at the same crystal structure). In this case, some of the iron ions in FeCO₃ can be replaced by manganese, calcium, and magnesium ions. It is shown that phases of the precipitates of non-stoichiometric composition (Ca_xMg_yMn_zFe)CO₃ thus formed are poorly crystallized which is attributed to the presence of defects in the crystal structure. They will exhibit inferior protective properties compared to stoichiometric FeCO_3. The film of FeCO₃ is packed, uniformly distributed and tightly adhering to the steel surface. An analysis of the diffraction patterns revealed a good crystallization of FeCO_3. The shape of FeCO₃ particles tends to a regular hexagonal habitus. The results obtained can be used in studying the resistance of corrosion products formed on the internal surfaces of gas production equipment under aggressive conditions in the presence of CO₂ in produced and transported hydrocarbons.

The formation of deposits in rectification columns and heat exchange equipment leads to violations of the technological process, and in some cases to an emergency shutdown of the equipment. To prevent deposits, it is necessary to know their chemical composition and genesis. We present the results of studying atypical organosulfur deposits in the heat exchange equipment of primary oil refining units. The structure and composition of the deposits were analyzed by scanning electron microscopy, and the chemical composition was determined using X-ray fluorescence analysis. It is shown that elemental sulfur present in the composition of the deposits acts as an additional corrosion factor that affects corrosion processes. Sulfur, being adsorbed on the surface of the equipment, blocks the access of the corrosion inhibitor to the metal surface thus reducing the effectiveness of the reagent. The neutralizer supplied to the helmet line of the atmospheric column can neutralize the acidic components (HCl and H₂S), but it is not able to neutralize the effect of sulfur on the inner surface of the metal of air coolers. The results obtained can be used to improve the control of heat exchange equipment of primary oil refining units.

Determination of the analytical relationship between real time changes in the quality characteristics of motor oils and an assessment of the state of the mechanism units subjected to friction is important when predicting the tribological characteristics of marine diesel engines. Changes in the lubricant parameters reflect the current technical condition of the engine components and assemblies. A method of process parameter matrix (PPM) is proposed to control the wear dynamics of a marine diesel engine. PPM is used to process statistical data on the performance of oils used in a MAN B&W Diesel Den 6L28/32A marine diesel engine through 2007 to 2021. The results of practical studies of changes in the physicochemical characteristics of motor oils in real operating conditions are presented. The results obtained can be used in the development of specialized software that allows obtaining operational information about the dynamics of engine wear.

A stochastic model of ductile-brittle (DB) transition based on a bimodal representation of random processes the critical temperature range of brittleness is proposed. Modeling was carried out in two stages. The results of impact tests of more than 1200 Charpy samples were used at the first stage to construct a stochastic model of the DB transition which revealed a bimodal distribution of the impact strength in the region of the DB transition. The model was based on the use of a fractional-power distribution to describe the probability of occurring the impact strength values. An analytical dependence of the probability of obtaining a given value of the impact strength at a given test temperature is proposed. At the second stage, the inverse problem was solved. The impact strength values were calculated from the given probability and test temperature. For this purpose, a generator of random numbers distributed according to the proposed bimodal law using the Monte Carlo method was constructed. The impact strength values were obtained using numerical methods. It is shown that the developed model does not contradict the existing experimental data and, probably, can be used to describe the DB transition both for well-known and new promising structural materials.

Diagrams of cyclic elastoplastic deformation in a general case characterize the resistance of a material to a low cycle loading and display a relation between current values of stresses and strains during deformation process. Those diagrams in the mechanics of deformation and fracture are described by rather complicated state equations with a nonlinear dependence on conditions and modes of loading including temperature, deformation rate, cycle form, type of the stress state, absolute size of sections, working medium, type of constructional material, etc. The entity of aforementioned factors affects a shape of the deformation curve (diagram) of the material and key parameters of the corresponding state equations, including basic characteristics of the mechanical properties, i.e., the elasticity module, yield point and ultimate stress, indicators of static and cyclic hardening. Experimental data on the kinetics of cyclic and one-way accumulated plastic strains in each loading half-cycle (cycle) obtained in static and low cycle tests of nickel superalloy specimens revealed that change in deformation characteristics exhibit a drastically nonlinear character in conditions of cyclic elastoplastic strain which is described on the basis of power equations and corresponding parameters of cyclic deformation diagrams. The parameters of those equations depend on the type of cyclically hardening/softening or stable material under deformation of the material in elastoplastic region. It is noted that resistance of materials to cyclic elastic-plastic strain can be described by a set of analytical expressions containing a kinetic function (which changes with number of loading half-cycles) in the form of power or exponential expressions depending on the cyclic properties and characteristics of the mechanical properties of the specific structural material. The obtained calculated and experimental data on the kinetics of strain of the alloy under study in conditions of cyclic elastoplastic loading, as well as on the parameters of the strain diagram (which are basic characteristics for the corresponding state equations) provide the possibility to take full advantage of using the deformation-kinetic criteria of damage accumulation under considered loading conditions to calculate the fatigue life of the structural elements manufactured from the alloy and operated, as a rule, under severe temperature and heavy-loaded conditions. The results of the experiments and calculations are given in the form of diagrams of cycle-by-cycle kinetics of the cyclic and accumulated plastic strains of the material for the soft and hard modes of loading in a wide range of test temperatures.

A review of scientific research data on the use of climatic cold carried out on the basis of institutes of the Federal research center «Yakut Scientific Center» Siberian Branch of the Russian Academy of Science is presented, natural low temperatures being used both as testing conditions and as a tool for experimental studies. The results of full-scale hydraulic tests of pressure vessels and pipes under conditions of low climatic temperatures, and under internal pressure created due to the effect of ice formation in closed cavities are presented. The results made it possible to determine the limit states of large-diameter pipelines, simulate the stress-strain state of the pipeline in thawed, freezing and frozen soils, substantiate the extension of the lifetime of pressure vessels, develop a technology for their welding, and determine the allowable size of defects in welded joints. It is shown that climatic tests of polymer, composite, construction, welding and other classes of materials provide for estimation of their service life under the impact of climatic factors. An experimental study of the response of solids to multiple collisions with ice granules at low climatic temperatures has been carried out along with the study of the processes of brittle fracture of their surface with the formation of splintery particles. Study of the effect of fibrous fillers of natural origin on the strength properties of fresh-ice based composition material revealed that introduction of fillers increases the strength characteristics of fresh ice by 2 – 3 times. It is shown that climatic features and a significant scientific potential of the Sakha (Yakutia) Republic provide for effective use of climatic cold as a tool for scientific research and solution of engineering problems in various sectors of the national economy.