Redefinition of the basic units of the International System of Units (SI) — the kilogram, mole, ampere, and kelvin, — which are now expressed in terms of fundamental physical constants means a substantial revision of the system. In particular, the new definition of the mole fixing the value of the Avogadro constant sets a unit of the amount of substance, which is independent of the unit of mass. We consider some consequences of redefining (the mole and kilogram) and focus on the uncertainty of measuring the amount of substance and related quantities which are important for description of the mixture composition. The issue regarding the molar mass of the substance and associated uncertainty is considered in detail It is noted that calculation of the molar mass using relative atomic masses, involves the molar mass constant which is not equal exactly to 1 g/'mol in the new SI. This introduces an additional, though very small, uncertainty of less than 1 x 10^-9 in relative terms. The budget of uncertainty for the amount of substance determined through the mass measurements when the mass is measured with the highest accuracy is scrutinized. It is demonstrated that for substances of less than 99.98% purity, the uncertainty associated to the purity is comparable to that of relative atomic masses of the elements. For high-purity substances, the uncertainty in the relative atomic masses have the largest contribution to the budget. Anyhow, the uncertainty associated to the molar mass constant is three orders of magnitude less than the nearest contribution to the uncertainty attributed to weighing. In the case of derived quantities which are the ratio of two quantities of the same kind, the additional uncertainty does not arise at all. This is illustrated by the calculation of the mole fraction of a component in the gravimetrically prepared gas mixture.

The sorption of Hg (II), Cd (II), and As (III) by natural aluminosilicate is studied. It is shown that the mineral absorbs those toxicants in a rather wide pH range, quantitative extraction of analytes being achieved in a neutral or close to neutral medium (pH values range within 7.0 - 8.0; 6.3 - 7.5; 7.4 - 8.5 for Hg (II), As (III), and Cd (II), respectively). The effect of the time of phase contact on the degree of extraction of elements is shown. The sorption capacity of the mineral in optimal conditions of the medium acidity (0.06 mmol/g for mercury, 0.31 mmol/g for cadmium, and 0.52 mmol/g for arsenic) is determined. The distribution coefficients attain values of about n X 10³ - n X 10⁴. A new combined method for determination of Hg (II), Cd (II), and As (III) in natural and waste water is developed and tested. The method consists in a preliminary group sorption concentration of the analytes by aluminosilicate, desorption of the analytes from the surface of the mineral and their subsequent atomic absorption determination. The correctness of the method is verified in analysis of spiked samples. The method is easy to use and exhibits high sensitivity, reproducibility and accuracy of analyte determination. The relative standard deviation does not exceed 0.13. Economic availability and possibility of using domestic sorption materials are the important advantages of the proposed procedure which can be used in the practice of laboratories monitoring the quality and safety of environmental objects.

Physical parameters of electric arc plasma as well as their time dependences are calculated when analyzing phosphate precipitates of the fission products of irradiated nuclear fuel. Phosphate concentrates of the fission products are known for their complex chemical composition and high thermal and chemical stability. Hence, direct atomic emission spectral analysis of phosphate powders without transferring them into solutions is advisable. Different conditions of sample preparation and synthesis of the reference materials determine the different chemical forms of the elements to be determined. This, in turn, affects the kinetics of their evaporation in the electrode crate and excitation processes in the plasma. The known mechanisms of those processes cannot always be transferred to specific conditions of the given method of analysis thus entailing the necessity of studying the effect of the samples chemical composition on the results of determination, proper choice of spectroscopic carriers, detailed study of spectra excitation processes in spectral analysis, and analysis of the physical parameters of the electric arc plasma. We used the lines Zn I 307.206 nm and Zn I 307.589 nm to measure the effective temperature of the central hot sections of the arc in a range of4500 - 6500 K. NaCl, BaCl₂ and NaCl + T1C1 were studied to reduce the effect of the sample elemental composition on excitation conditions of the spectra and their stabilization as a spectroscopic carrier. In control experiments we used carrier-free samples. The coincidence of the values of the plasma physical parameters within the measurement error not exceeding 20%, as well as the identity of the nature of the kinetic curves for samples of phosphate precipitates and synthetic reference materials prove their correctness. The result of the study substantiate correctness of the direct atomic-emission spectral procedure in analysis of phosphate concentrates of fission when using synthetic reference materials.

The effect of the instrument parameters (such as types of the detectors, crystal analyzers, and primary radiation filters, as well as x-ray tube operation modes, angular spread of collimators and settings of the window of the amplitude analyzer) of an x-ray fluorescence wavelength-dispersive spectrometer on the fluorescence intensity is shown using the literature data. Adjustment of the corresponding nodes of the spectrometer can result in improvement of the metrological characteristics of measurements. The influence of the aforementioned nodes and time of exposure on the metrological characteristics of measurements is exemplified in determination of Al, Si, Ti, Fe and Sn content in a range of 10^-2 -10^-3 % in potassium fluorozirconate. Determined values of the contrast of the analytical signal, detection limit and standard deviation of the results showed that the effect of the instrumental parameters of the spectrometer is critical only when the content of the elements is lth3 % or less. The optimal operation modes of the x-ray tube depend on the atomic number of the element, e.g., for light elements it is advisable to use a higher current strength at a lower voltage, whilst filters of primary radiation have no positive effect. The best characteristics of the measurement results were obtained with LiF200 crystal-analyzer and 0,25\i collimator. Settings of the amplitude discriminator to a hall-width of the peak are preferable, but at extremely low intensities of the analytical signal, comparable to the background, the opposite situation occurs. The exposure time also significantly affects the spread of measurements only at a 10^-3 % element content region which entails the necessity of increasing the measurement time up to more than 90 seconds. However, for tin due to extremely low contrast, an increase in the exposure time to more than 60 seconds does not reduce the spread of measurement results.

A comparison of different classification algorithms for dynamic description of the quality of industrially produced mineral fertilizers is presented. Five brands of fertilizers (NPK 16-16-8, NP(S) 12-40 (10), NPK(S) 4-30-15 (16), NPK(S) 0-20-20 (5), MAP (NP) 12-52) were analyzed using optical and X-ray fluorescence methods of control. A method of identifying the characteristic features of industrially produced mineral fertilizers using constructed “objects-characteristics” data array is described. Estimates of the quality of determination of physicochemical parameters of fertilizers (the content of N, P, К and total content of S, types of the particle size of the press-fitted granules and the pre-drying conditions) are given. The procedure of choosing optimal parameters for each considered classification algorithm is shown. The algorithms were estimated using the F-measure (harmonic mean of “precision” and “recall” of classifier). The training of the classification algorithms and assessment of the quality of their “work” were carried out according to the cross-validation strategy on 10 data sets (folds) with a delayed test (30% of the total data volume). The total value of the quality metric was calculated as the average for all classes. The use of the principal component analysis for informative representation of the studied objects on the plane is described. Finally, a combined method of analysis for automated and informative study of industrial products was proposed.

The results of studying the effect of plastic deformation and subsequent heat treatment on the acoustic and electromagnetic properties of austenitic steel 12KM8N10T (analog AISI 321) are presented. Cryogenic corrosion-resistant austenitic steel 12Khl8N10T undergoes strain-induced martensitic transformation, which significantly changes the electromagnetic, elastic and strength properties of the material. The formation of the new phase in conjunction with the process of plastic deformation affects the crystallographic texture of the alloy. A change in the texture of the material was estimated using the acoustic anisotropy parameter determined by the ultrasonic method. Changes in the magnetic properties attributed to appearance of the ferromagnetic phase of martensite in the paramagnetic austenite matrix were fixed with an eddy current ferritometer. It is shown that at the initial stage of plastic deformation (uniaxial tension) the value of the acoustic anisotropy parameter decreases probably due to the fact that change in the texture is more affected by the process of austenite deformation than the formation of α'-martensite. Further deformation of the material promotes formation of the new phase thus strengthening the impact of the new phase on the crystallographic texture and results in increase in the acoustic anisotropy parameter. It is shown that annealing at a temperature of 350, 600, 700, and 1050°C of pre-deformed stainless steel decreases the parameter of acoustic anisotropy and the volume content of the magnetic phase. It is shown that the parameter of acoustic anisotropy of the material drops to zero after annealing at 600°C, whereas at a temperature of 1050°C the martensitic phase completely disintegrates and the texture is determined only by the austenite phase.

Study of the structure of optical crystals and defects in them is one of the most important problems in crystal physics, crystallography and material science. Nowadays, study of the nanostructures, including the linear defects in crystals is of particular importance. Defects, and first and foremost linear imperfections of the crystal structure, significantly reduce the operational physical properties of optical crystals. Analysis of the properties of those defects, their orientation in the crystal lattice, as well as developing of the methods for determination of the crystallographic orientation of linear defects are the most important in view of the possibility of improving the properties of optical crystals. A method for rapid determination of the crystallographic orientation of linear defects (dislocations, clusters, linearly extended bulk inclusions, etc.) in optical crystals is presented. The orientation of a linearly extended micropore in an isotropic optical transparent fluorite crystal was determined using an optical microscope. The readings of the scale of the eyepiece drum were recorded when rotating the crystal fixed in the crystal holder of the microscope. Corrections for the refraction of light in the bulk of the crystal were taken into account analytically. The crystallographic orientation of the microporous in a transparent fluorite crystal was studied in detail. Crystallographic indices of micropore orientation corresponded to [100]. We developed an efficient rapid procedure for determination of the orientation of internal linear defects (imperfections) in optically isotropic crystals using an optical microscope. The restrictions imposed on the angles of crystal rotation depending on the value of the refractive index are considered for the given method of determination.

We develop a universal method of physicochemical refining of the market wood pulp to the level given by the requirements of State standards for fibrous semi-finished products for deep chemical processing into various functional derivatives and artificial materials (Na-CMC, colloxylin, pyroxylin, viscose and cordage fibers). An experimental laboratory modular setup was designed and manufactured at the Semenov Institute of Chemical Physics (RAS). The modification includes the following stages: preparation of the raw materials, chemical modification, washing, and drying of the final product. At the first stage the original market pulp was dispersed to obtain a homogeneous suspension, cleaned and dried. After washing, the refined cellulose was dried in two stages: i) microwave drying to a moisture content of 45 - 50%; ii) convective drying with warm air to a moisture content of 5 - 9%. The basis of chemical modification is the stage of cold refining. Compared to other methods of refining wood pulp (acid-alkali treatment, hot refining) cold refining does not require special equipment which operate at elevated temperature and pressure. The developed procedure of physicochemical modification of the market wood pulp is universal, since it has no restrictions on the brand of the initial raw material. Depending on the quality requirements to the final product, the proposed method provides obtaining all brand of cellulose for chemical processing — viscose cellulose, acetate cellulose, cord cellulose. Mass fraction of the alpha-cellulose in the final product ranges from 93 to 99%.

An optoelectronic method for detecting dust deposition on printed circuit boards (PCB)of electronic equipment, which can be used to inform about the critical thresholds of dust accumulation is developed with allowance for the humidity index. The proposed method in combination with the developed mathematical model, functioning diagrams, and light beam motion patterns is used to consider a possible construction and block diagram of the algorithm of control program for the microcontroller of desired implementation of the experimental setup. The principle of operation of the optoelectronic method for detecting dust depositions on printed circuit boards of electronic equipment with allowance for the humidity is following. The light pulses are periodically emitted by two LEDs with a wavelength λ₁= 565 nm (to assess the level of dust deposition) and two LEDs with a wavelength λ₂ = 930 nm (to take into account the level of humidity). The reflected signals from the three plates are taken by the photodiode. The first and second plates placed in a sealed enclosure have an artificially deposited maximum level of dust (humidity 10 and 90%, respectively). The third plate is a control. The third platinum is the control plate. The plates and PCB are made of the same materials. The level of deposited dust (mass concentration per unit area) which triggers the leakage currents between the conductors of the printed circuit board is determined experimentally and depends on the minimum distance between the printed conductors, through which the maximum current flows in a given electronic equipment and on the thickness of the dust layer deposited on the conductors at the maximum permissible humidity specified for the equipment.

The paper describes one of the most promising ways of structure health monitoring based on analysis of the kinetics of local stress-strain state. Comparison with other methods of damage detection and advantages of the stress-strain state control are considered. To implement this method of monitoring, two types of sensors are considered: strain gauges and fiber Bragg gratings (FBG). The advantages of FBG, due to which their use in operation is most preferable, are presented. The possibility of using stress-strain state control is analyzed for a promising transport aircraft using the results of tensometry under cyclic loading. The relevance of the work is confirmed by various examples of using monitoring methods in on-board systems during operation. The possibility of monitoring the airframe parts is demonstrated for longitudinal fuselage joints as an example. The change in the stress-strain state of the longitudinal joints, caused by structural damage was confirmed by tensometry analysis and by analysis of the stress-strain state of bearing sheet by the finite element method (FEM), taking into account the fatigue cracks originated during cyclic loading. The results of the calculation are compared with the tensometry data. Proceeding from the results of the calculation of the stress-strain state of the damaged and undamaged structure, the zones of the greatest deformation change are determined to optimize potential locations for the sensors. The optimal placing of the sensors for monitoring the integrity of the joints is proposed. The study confirms that the method of damage monitoring of the structure, developed on the basis of changes in the kinetics of the stress-strain state, can be successfully used in tests for maintaining the integrity of joints and other places with multi-site damages, where the methods of visual and non-destructive testing are not effective.

The probability of occurring emergency situations increases in conditions of severe climate of the Arctic. Therefore, addressing the problems related to the risk assessment of accidents at oil and gas facilities in the Arctic zones based on acceptable risk criteria is of particular importance. Uncontrollable development of emergency situations is followed by emission of a significant amount of oil products and constitutes serious ecological danger, and also can lead to considerable destructions and death of people resulted from fire and explosion. Therefore, the goal of the study is development of the methods for analysis and assessment of the risk of accidents in reservoirs and gas pipelines at low temperatures to increase the industrial safety of hazardous production facilities operating in conditions of the Arctic North. The results of brittle fracture analysis and accident risk assessment for reservoir and gas pipeline under arctic climatic conditions are presented. Statistical data processing of accidents allowed us to determine the rupture sources, develop a “fault tree” of brittle fracture of reservoirs, “event trees” of reservoir explosion and gas outflow from a gas pipeline, with allowance for the frequency of scenarios for quantitative risk assessment. Currently the probabilistic approach is considered one of the most promising. Accident statistics and experience of previous risk analyses can provide a useful contribution to the process of hazard identification. We focus on the scenario approach to the problems of hazard identification and assess the probability (frequency) of emergencies proceeding from the analysis and systematization of the statistical data on the accidents on reservoirs and gas pipelines at low ambient temperatures using the “event trees” and “fault trees” which provide determination of the most critical scenario and expected risk from accidents. Thus, risk assessment of accidents at hazardous production facilities in the Arctic zone using criteria of acceptable risk will allow estimation of hazards with unacceptable level of risk and development of recommendations and measures to reduce them.

Among the thin-walled structural elements combining lightness and high strength, film and membrane elements are used most widely. Smart coatings with a complex structure are being actively developed nowadays. Proceeding from their functional duty, it is advisable to produce non-planar forms — shell films, membranes and coatings — which can have a complex structure specified by the designer or acquired in the process of manufacture and operation. Study of the mechanical properties of the shell films and membranes with a complex structure using standard uniaxial method of testing appeared ineffective. Complex structures with macro-heterogeneity should not be studied by indentation methods, capable of determining the material properties in the vicinity of the point in question. We developed an experimental-theoretical method for determination of the mechanical characteristics of non-planar films or membrane compositions of complex structure. At the stage of experiment, the stiffness of a non-planar sample (e.g., spherical, cylindrical or toroidal shape) fixed along the contour and loaded with by a unilateral surface pressure is estimated. Then, using the ratios derived from the nonlinear theory of shells, the integral mechanical characteristics of the shell sample material are determined: the reduced modulus of elasticity (elastic strain) or reduced conditional modulus of elasticity (plastic strain), deformation curves, etc. The relations for thin spherical membranes for the case of large displacements and deformations, as well as relations for thin cylindrical membranes of variable radius are considered. Results of the case study of rubber spherical membrane with holes and defect-free catenoidal shell are presented to illustrate the developed methodology.

The drawbacks of the existing methods of analysis of textile fibers and threads at break, due to the incompatibility of the laboratory tests with conditions of their strength loading during operation and processing are considered. A method of testing based on a pendulum impact tester and algorithm for determination of the work of rupture, tensile strength and relative deformation of the material using angular coordinate of the pendulum are developed. The developed device provides visualization of the testing results for various types of yarn and threads. The results are compared with the data obtained on a standard tensile strength machine RM-30-1. Differences in the relative deformation values of tested materials are described and interpreted.