Sequential extraction procedures (SEP) have been widely used for the fractionation of trace elements in soils according to their physicochemical mobility and bioaccessibility. Potassium/sodium pyrophosphate in alkaline medium may be considered as the most appropriate extracting reagent for the recovery of amorphous metal-organic complexes, which play a very important role in biological, physical, and chemical processes in soil. However, the selectivity of pyrophosphate has been poorly studied. In the present work the ability of pyrophosphate to attack mineral inorganic phases of environmental solids was assessed using dynamic extraction, which allows one to minimize artifacts and mimic natural conditions. Samples of gabbro and granite containing nearly no organic compounds were taken as example. The eluents applied addressed exchangeable, specifically sorbed, bound to Mn oxides, and bound to metal-organic complexes fractions extractable by 0.05 M Ca(NO3)2, 0.43 M CH3COOH, 0.1 M NH2OH · HCl, and 0.1 M K4P2O7 at pH 11, respectively. As expected, pyrophosphate extraction leads to a partial dissolution of elements bound to inorganic compounds. The recovery of aluminum, iron, manganese, and rare earth elements by pyrophosphate is up to 4% of their total concentrations in samples. The results were discussed on the basis of coordination chemistry of pyrophosphate complexes. In general, pyrophosphate extraction could be further regarded to be sufficiently selective for the dissolution of metal-organic complexes while using SEP in environmental analysis, soil science, and biogeochemistry. Nevertheless, in the interpretation of the fractionation results, a partial dissolution of mineral inorganic phases should be taken into consideration, especially for soils with low content of organic compounds.

Two methods — ICP-MS and ICP-AES are used for certification of the new reference material — needles of Siberian pine (NSP-1). Techniques of the analysis include decomposition of plant samples in two different ways: acid digestion in a microwave system MARS-5 and lithium metaborate fusion followed by ICP-MS and ICP-AES analysis of the solutions. Simultaneous determinations of all the elements were carried out in low, medium and high resolution using SF-mass-spectrometer ELEMENT and atomic-emission spectrometer IRIS Advantage with external calibrations and internal standards (In — ICP-MS, Sc —ICP-AES). Middle and high resolutions of ICP mass spectrometer were used for interference corrections. Data obtained by ICP-MS and ICP-AES with different decomposition techniques are in good agreement. The ICP-MS and ICP-AES techniques have been validated by the analysis of three plant reference materials: LB-1 (leaf of a birch), Tr-1 (grass mixture) and EK-1 (Canadian pondweed). These techniques were used for the determination of 38 elements in the new reference material NSP-1. Relative standard deviations for most of the determined elements were below 10%. Combination of ICP-MS and ICP-AES techniques for certification of the new reference material makes it possible to expand the set of elements to be determined and to reduce the total analysis time.

A method of calibration in relative concentrations (concentration ratio) previously used only in analysis of non-ferrous and ferrous metals was first implemented when performing silicate analysis of geological materials using atomic emission spectrometry with inductively coupled plasma (AES-ICP). Prior to apply the Concentration Calibration Ratio to analysis of geological materials it is necessary to consider and address the following problems: some of the components are not determined by ICP-AES, matrix elements may be present in different oxidation states. Sample preparation of ores and geological materials was carried out in autoclaves heated at 180°C using HotBlock 200 system. A mixture HCl/HNO3/HF was used at the first step and then added with a 4% H3BO3 solution. The repeatability and intermediate precision of determination when using Concentration Ratio Calibration, calibration without internal standard and Calibration with In as internal standard are compared for determination of SiO2 (content 40 – 75%), Al2O3 (5 – 20%), CaO (0.25 – 15%), MgO (0.1 – 15%), Fe2O3 (0.5 – 15%), Na2O (0.5 – 10%), K2O (0.5 – 5%), P2O5 (0.01 – 0.3%), MnO (0.03 – 0.5%), and TiO2 (0.05 – 2%). The use of Concentration Ratio Calibration provides better metrological characteristics, repeatability and precision in analysis of geological materials compared to other calibration procedures due to elimination of the calibration error of balances and volumetric flasks from total error of analysis; measuring the large intensities of the base element; and better accuracy of measuring the intensity ratio compared to absolute intensity measurements.

We present the results obtained using the equipment available at the Center for collective use “Composition, structure, properties of structural and functional alloys” NRC “Kurchatov Institute” — CRISM “Prometey”: DIL 805A/D (TA Instruments) and DIL 402C (Netzsch) dilatometers. Dilatometric analysis which provides determination of the temperature coefficient of linear expansion and the temperature of phase transitions, as well as evaluation of the transformation kinetics, can also allow simulation of heat treatment modes to identify the size of the former austenitic grain using vacuum etching and conduct the research aimed at improving the technology of thermal and thermomechanical processing (TMO) of steels and alloys. The experiments were carried out both in vacuum and in dynamic helium atmosphere. The main methodological difficulties that we have faced with are described. For steels of martensite and martensite-bainite class (38KhMA, 38KhN3MFA, 20Kh3NMFA) conditions of vacuum etching in the chamber of the dilatometer are specified. The efficiency of the method for martensite-bainite steels in determination of the grain size compared to traditional methods of etching is deminstrated. The effect of thermodeformation parameters on the size of austenitic grain is estimated. When modeling the heat treatment modes by the dilatometric method, the microstructure of KhN55MVTs nickel alloy was also analyzed. Changes in the size and morphology of the grain structure at different stages of heat treatment are revealed. The obtained results were used to adjust the current modes of heat treatment and obtain a uniform fine-grained structure. The combined application of dilatometric and metallographic analyzes after vacuum etching of the material decreases the production costs attributed to obtaining the desired microstructure upon thermal and thermomechanical processing of the products and blanks.

The results of comparative analysis of assessing modes, parameters and means of radiographic control of welded joints of critical duty using the Russian (GOST) and international (ISO) standards are presented. Comparison was carried out by the sensitivity of control, permissible radiation energy (affecting the formation of the contrast of the radiation image), and minimum focal length (determining the sharpness of the resulting optical image). Requirements of the ISO system for the sensitivity of control are higher, than that of the State standard specification system. The sensitivity assessment in the ISO system is carried out using the wire indicator, the dimensions of which are smaller than the dimensions of the grooves of the groove sensitivity standard, regulated by GOST. However, the choice of the radiation energy in the system requirements GOST is stricter than that in the ISO system. This provides enhanced contrast of the generated radiation image. The conversion of the radiation image into an optical one using the ISO system is carried out using film systems of a high optical density. According to the ISO requirements transformation of the radiation image to the optical one is to be carried out using film systems of the certain class. And, as a result, transformation of the radiation image to the optical occurs in the field of high gradients. GOST imposes no requirement to film systems, since there is the only one class of domestic film on the market. The requirements to the minimum allowable focal length (GOST) are higher compared to the ISO system, which makes it possible to obtain better sharpness of radiographic images. Performance monitoring according to GOST also exceeds that of ISO. As a result, we can conclude that the quality welded joints should be monitored using the complete set of the accepted standards.

The results of testing thin-walled welded joints (high-temperature assemblies of epitaxial installations) obtained by electron-beam welding using the eddy current method are presented. The tightness of those parts and assemblies is controlled by vacuum and compression leak detection methods, based on increasing the test gas concentration on the one side of the test surface and sampling it for mass spectrometric analysis on the other side. Helium mass spectrometric leak detectors are now widely used in aerospace, electronics and chemical industries, as well as in the instrument making industry and scientific research. The eddy current method provides a high scanning speed and allows timely detection of the defects and prevention of the risk of accidental wear of thin-walled elements and parts of aerospace and petrochemical equipment. The goal of this work is to optimize the control of welded joints of thin (0.2 and 0.5 mm) tantalum screen using a VEKTOR-60D detector and eddy current method. The device provides the use of overhead or flow eddy current differential, tangential and absolute transducers operating at a frequency from 10 Hz to 20 MHz, as well as various dynamic transducers. The device is designed to control metal products, carbon plastics and composites for the presence of defects such as surface and subsurface cracks, discontinuities and homogeneity of materials. VEKTOR-60D allows one to get a simultaneous signal display on the flaw detector screen both in the amplitude-time and complex planes. The used sensors (PVDT-1000-2, PVD-200-2,3, and VP160A45) provided detection of the defects across the entire width of the weld and heat-affected zone in one pass along the welded joint. The defect of the welded joint of the tantalum screen was revealed as incomplete penetration (nonpenetration in the weld root) in accordance with the classification of GOST R ISO 6520-1–2012. The results proved that a VEKTOR-60D eddy current detector can be successfully used in monitoring defects in thin-walled welded joints.

Safety, survivability, and serviceability of the equipment are governed by the strength characteristics of the separate units and elements which can contain initial or operational defects such as superficial differently oriented semi-elliptical cracks. Numerical methods of calculation provide a large bulk of information about the stress-strain state (SSS) of those elements proceeding from the given algorithms for calculating the corresponding fracture models. Change in the type of the SSS near the crack contour when going from the bulk to the surface depends on the constraint of deformations along their front, i.e., on the 3D character of the SSS. Diagnostics of the form change of the defects (surface differently oriented semi-elliptic low-cycle cracks) is carried out on the basis of experimental results and numerical solutions. The data of the finite element modeling are implemented on the basis of macros of the ANSYS program complex. The regularity of the directionality of developing the elastoplastic fracture under low-cycle loading is studied. The proposed methodology is proved by the parametric equations of the kinetics of forming changes of the cracks under study in the fractographic analysis of the surfaces of their development. The results of testing samples with semi-elliptic cracks under low-cycle loading are used in analysis of the parameters of the morphology of the surfaces of the developed defects. The results of measuring fields of elastoplastic deformation intensity in the crack tip and geometrical characteristics of the fracture surface development are presented. Analysis of the dynamics of the local stress-strain state near the contour of multi-oriented defects in parts and structural units of the equipment showed a good agreement between the experimental parameters of the geometry of developing cracks and characteristics obtained by numerical methods. The presented parametric equations specify the characteristics of nonlinear fracture mechanics thus providing reliable estimation and forecasting of survivability, and safety of serviceability of the critical equipment. The deformation criteria of nonlinear fracture mechanics are used to demonstrate the dependence of fracture development on the 3D character of the stress-strain state indicating to the directionality of the geometric development of the fracture surface form.

The results of using early damage diagnostics technique (developed in the Mechanical Engineering Research Institute of the Russian Academy of Sciences (IMASH RAN) for detecting the latent damage of an aviation panel made of composite material upon bench tensile tests are presented. We have assessed the capabilities of the developed technique and software regarding damage detection at the early stage of panel loading in conditions of elastic strain of the material using brittle strain-sensitive coating and simultaneous crack detection in the coating with a high-speed video camera “Video-print” and acoustic emission system “A-Line 32D.” When revealing a subsurface defect (a notch of the middle stringer) of the aviation panel, the general concept of damage detection at the early stage of loading in conditions of elastic behavior of the material was also tested in the course of the experiment, as well as the software specially developed for cluster analysis and classification of detected location pulses along with the equipment and software for simultaneous recording of video data flows and arrays of acoustic emission (AE) data. Synchronous recording of video images and AE pulses ensured precise control of the cracking process in the brittle strain-sensitive coating (tensocoating)at all stages of the experiment, whereas the use of structural-phenomenological approach kept track of the main trends in damage accumulation at different structural levels and identify the sources of their origin when classifying recorded AE data arrays. The combined use of oxide tensocoatings and high-speed video recording synchronized with the AE control system, provide the possibility of definite determination of the subsurface defect, reveal the maximum principal strains in the area of crack formation, quantify them and identify the main sources of AE signals upon monitoring the state of the aviation panel under loading P = 90 kN, which is about 12% of the critical load.

The problems of ensuring the reliability and safe operation of long-running hazardous industrial facilities, in particular gas pipelines, after 50 years of operation are considered. The goal of the work is developing a method for assessing metal embrittlement of long-running main gas pipelines (MG) using a non-destructive method for monitoring and improving operational reliability. Experimental studies of the samples of the pipes of the main gas pipelines revealed the parameters most sensitive to the processes of structural degradation. The applicability of those parameters to assessing the degree of degradation is substantiated. Analysis of the results of mechanical and acoustic studies revealed correlation with an essentially large value of the correlation coefficient. Based on this correlation, a method for assessing the toughness has been developed. The experimentally obtained limit values of the studied characteristics at which the operation of the structure becomes dangerous are presented. A flowchart has been developed for monitoring changes in the toughness of the gas pipeline steel after long-term operation. The experimental results and developed method for estimating the limiting state of the gas pipeline material were used during technical diagnostics of non-project sections of the Mastach — Berge — Yakutsk gas pipeline to determine real operational characteristics and form a database of the studied indicators for their further monitoring. The proposed method will improve the efficiency of accumulated information on the structural reliability and provide the possibility of assessing the degree of pipe metal degradation without conducting mechanical tests and making samples in the process of technical diagnostics thus reducing the material costs for conducting scheduled maintenance of the pipelines.

The lack of traceability of the results of ash content measurements to the state standards of measurement units is considered. The problems of ash mass fraction measurement in food industry are revealed: dependence of the measurement results on conditions of the analysis, incomplete information on the modes of measurements and metrological characteristics in standardized methods, the absence of reference materials. We present information about the measurement method and equipment for implementation of the State primary reference procedure (SPRP) for measuring the ash mass fraction in food and foodstuff (grain, grain products, starch, sugar, dairy products, low-lactose products, lactose-free products, compound feeds and feed components) and describe the procedure of determining the methodological parameters (temperature, duration of combustion, weight of sample) in the course of the SPRP development using a stereoscopic pancratic microscope and thermogravimetric analyzer with mass spectrometric detector (implementing TGA-MS methods) included in the State primary measurement standard of mass fraction and mass (molar) concentration of water in liquid and firm substances and materials GET 173 – 2017. The described algorithm for estimating the uncertainty of the ash mass fraction measurements using multifactor experiment, regression analysis and single-factor ANOVA provide information about the sources of the uncertainty and their contributions to the total uncertainty of measurement results. The metrological characteristics, scope and purpose of SPRP are presented. The results of interlaboratory comparisons confirming the equivalence of the developed SPRP to similar measurement procedures (methods) of foreign countries are presented. The applicability of the developed SPRP for determination of the certified values of the mass fraction of crude ash to testing reference standards of compound feed composition is demonstrated.