The review analyzes the current state and prospects for the development of high-temperature dilatometry. Basic definitions and concepts are given. The main types of dilatometers using contact (mechanical) and remote (optical) measurement methods are considered; some specific installations are described. Limiting factors of known methods are analyzed. Technological progress, which produces materials with new properties, requires the creation of approaches to study the characteristics and application possibilities of such materials, as well as, possibly, forecasting the directions of materials science. Techniques that can ensure further progress in high-temperature dilatometry technology are analyzed. This review is addressed to researchers – metrologists, material scientists, physicists working in the field of dilatometry, as well as specialists who create measuring instruments.

In the Russian Federation, a development type of a state primary special measurement standard for the volumetric flow rate of natural gas at pressures up to 10 MPa has been created on the base of a piston prover with four parallel-connected cylinders with an internal diameter of 500 mm. The design of measurement standard utilizes simultaneous active actuation of the four pistons within the cylinders via piston rods connected to a common hydraulic system piston rod.In paper the measurement equation compiled that includes more than twenty influencing parameters and determines the value of the volumetric flow rate through a calibrated transfer standard as part of the state primary special standard. Equation takes into account the volumetric flow rate of gas reproduced by the piston prover, the change in the volumetric flow rate as a result of the change in the amount of gas in the attached («dead») volume during the measurement time, and the volumetric flow rate of gas leaks between the cylinder chambers through the piston seals.Based on the measurement equation, an assessment of the expanded uncertainty ( k = 2) of the reproduction of the volumetric gas flow rate carried out and the percentage contribution to this value of individual input parameters under different modes determined.From the results of the calculations, the accuracy measurements indicators of the state primary special standard declared in the technical specifications for its creation confirmed.

Thermal expansion is an important design parameter of materials, which should be taken into account when developing, producing and using products. To control this significant characteristic of new materials, it is necessary to develop equipment, methods and measurement procedures that take into account the novelty of the specific behavior of these materials. The production of specially shaped samples is the main limitation in thermal expansion measurements. This primarily applies to new materials (heterogeneous, composite, poorly processed) developed for special tasks. These factors necessitated the development of a method for measuring the temperature coefficient of linear expansion of products and materials with arbitrary sample shapes, which was not available in previous implementations of interferometric methods. An interference speckle dilatometer SD was developed for measuring samples with irregular shape in the temperature range from 200 to 400 K. When creating the speckle dilatometer SD, the speckle interferometry method was implemented to measure the elongation of samples with an irregular surface with nanometer sensitivity. Since this device has no analogues, a study was conducted on the uncertainty components arising when measuring the thermal coefficient of linear expansion of materials on this device. The analysis of the uncertainty components of the measurement of the thermal coefficient of linear expansion of materials on the speckle dilatometer SD was carried out. An experimental determination of the measurement uncertainty of the thermal coefficient of linear expansion of TCLE measures of arbitrary shaped samples was obtained using the SD speckle dilatometer. After research and initial certification, the developed measurement instrument was approved and included in the State Secondary Standard of the unit of thermal coefficient of linear expansion of solids in the range of values from 0.05 · 10–6 to 100.0 · 10–6 K–1 in the range of temperature values from 90 to 1,900 K.

Raman spectroscopy is mainly used for qualitative analysis, since the intensity of Raman lines is instrument dependent. At the same time, the high selectivity of Raman spectra stimulates interest in finding ways to use them for quantitative analysis as well, and the development of methods to effectively apply Raman spectroscopy for quantitative analysis is quite relevant.The aim of the study was to investigate the possibilities of using the measure developed at the All-Russian Scientific Research Institute for Optical and Physical Measurements and designed for calibration of Raman instruments on the Raman shift wavenumber scale for quantitative analysis from Raman spectra.The developed measure (registration number in the Federal Information Fund for Ensuring Uniformity of Measurements 93847-24) is a polymer film made of polystyrene with sulfur addition and allows storing and transmitting a unit of Raman shift wavenumber for Raman scattering excitation wavelengths of 532, 633 and 785 nm.The possibility of using this measure for quantitative analysis of substances by measuring the intensity of Raman lines in instrument-independent units is considered. It was found that the use of the measure allows to determine the volume fraction of individual substances (ethanol) with relative random error less than 3 % and relative systematic error less than 6 %. To analyze multicomponent mixtures (alcohols, sugars) with the help of the measure, a multivariate calibration was constructed using the Partial Least Squares method. In this case, the volume fraction of components in an unknown sample was determined with a relative error not exceeding 15 %.The practical significance of the obtained study results allows to calibrate Raman microscopes and spectrometers on the Raman shift wavenumber scale, as well as to carry out quantitative analysis of individual substances and multicomponent systems using Raman spectroscopy.

The accuracy of determining the physical and chemical properties of a liquid, in particular, assessing the viscosity of the liquid used, is considered an important technical problem in medicine, food, oil, chemical industries, as well as in other areas that determine the quality and safety of human life and activity. For example, assessing the viscosity of the liquid used is a key stage in the design of hydraulic systems. Today, the improvement of methods for determining the viscosity of a liquid is on the path to automation (digitalization) of measurement instruments and methods. In this area, the activities of metrologists and engineers are consistent with the national program «Digital Economy of the Russian Federation» adopted in 2017. The article discusses the capillary method for determining the kinematic viscosity of a liquid as the most accurate of all possible methods at present. The method is based on determining the time of liquid flow between two marks, which are applied to the walls of a glass capillary viscometer forming a measuring tank. One of the main problems of this method is that all stages of measurement are performed by a person, even recording the moment when the liquid meniscus crosses the mark, which is a violation of one of the key principles of process automation – independence of execution, which only implies monitoring the operation of the system. Since ready-made solutions do not fit the laboratory’s measurement tasks, the management decided to develop and conduct a study of an information and measuring system that will carry out the process of detecting the liquid meniscus at the mark level, as well as recalculate the measured time interval into the kinematic viscosity value. The key decision in this development is the choice of a sensor for detecting the liquid meniscus. Based on the literature review, it was decided to use a photoelectric sensor. A study of the transmission spectra of liquids used in this method was conducted to select the wavelength at which the sensor will operate. Thus, a type of photoelectric sensor designed to operate in the UV range has been selected to automate the method of detecting the liquid meniscus when it crosses a mark applied to a capillary tube. The article is addressed to metrologists who perform verification and calibration of glass capillary viscometers, specialists in the field of experimental and theoretical viscometry. The method proposed by the authors can become the basis for further improvement of the method for measuring the kinematic viscosity of a liquid.

Establishing the pinpoint accuracy of national primary standards for units of mass and volume flow rates (mass and volume) of liquid (water) is a priority in the national economy of most states. In Russia and abroad, the principle of operation of standards for units of flow rate and amount of liquid is based on the gravimetric weighing method, i. e., on measuring the mass of liquid entering a weighing container over a certain averaging time interval. The decisive condition for the accuracy of the result of the standard is the stabilization of liquid flow rate, as well as the choice of the optimal method for creating a forced flow of liquid in the pressure pipeline and measuring line. The widely accepted method of creating a forced flow of liquid by placing it at a height or supplying it using pumps has one inconvenient consequence – the bulkiness of the standard design. The creation of such a design entails economic, labor, and time costs, which can adversely affect the test conditions and results. The author’s innovative method of active damping of pressure and fluid flow fluctuations, which eliminates the need to place the pressure tank at a great height above ground level, allows minimizing inconveniences. This method is implemented in the pressure pipeline and measuring line of the reference installation 3 of the State Primary Special Standard of Units of Mass and Volume of Liquid in a Flow and of Mass and Volume Flow Rates of a Liquid GET 63–2019. The purpose of the article is to substantiate and experimentally confirm the high efficiency of this method. The results of experimental research of changes in the absolute pressure in the air cushion and the liquid level in the pressure tank of the stabilization module confirmed the efficiency of the proposed method based on the obtained minimum values of the relative deviations of the instantaneous and average liquid flow rates. The engineering solution presented in the article is of interest to economic entities and commercial organizations interested in reducing the costs of testing the volumetric flow rate (mass and volume) of liquid (water).

Electrical steel is a soft magnetic material used in the manufacture of various electrical equipment intended for the transmission and conversion of electricity and used mainly in alternating magnetic fields of industrial frequencies. The key properties of such a material are AC magnetic properties, which are standardized when assessing the compliance of the material with the requirements of both Russian and foreign standards. The article presents information about the aspects of the development of reference materials for AC magnetic properties of electrical cold-rolled non-oriented steel made in the form of strips for the Epstein frame. The main feature of these reference materials is that the value of one of the two certified characteristics (specific power of magnetic losses) is transmitted directly from the State primary standard, and the other (magnetic induction amplitude) is determined in accordance with a certified measurement procedure. Their use will provide the possibility of a comprehensive and reliable determination of the magnetic characteristics of samples of non-oriented electrical steel normalized in accordance with the requirements of current standards.

In this work, algorithms for the characterization of reference materials are developed based on the data model of an interlaboratory experiment containing hidden uncertainties. These algorithms make it possible to evaluate hidden uncertainties, and, taking into account these estimates, adjust the data and obtain an agreed value of the certified characteristics. The Monte Carlo method was used to study the properties of estimates of hidden uncertainties, as well as the study of new algorithms in comparison with traditional ones.

The establishment and control of the metrological characteristics of the determination of trace elements in biological materials is an urgent task due to the wide application of these measurements in medical laboratory diagnostics. In the course of the research, the process of developing a primary reference procedure for measuring the mass fraction and molar concentration of copper and zinc in biological materials by isotope dilution mass spectrometry is presented. The optimal conditions for sample preparation and measurements by isotope dilution and mass spectrometry with inductively coupled plasma are determined in order to increase the accuracy. The sources of uncertainty are studied; the contribution of each source to the uncertainty budget is estimated. During the certification of the developed measurement procedure, the following metrological characteristics were determined: the measurement range of the mass fraction of copper and zinc is from 1 ∙ 10–6 to 1,5 ∙ 10–3 %, the measurement range of the molar concentration of copper and zinc is from 2 to 20 µmol/dm3, the relative expanded measurement uncertainty of the mass fraction of copper is (7.1–7.5) %, the relative expanded uncertainty of the mass fraction of zinc is (8.9–9.2) %, the relative expanded uncertainty of the molar concentration of copper is 8.8 %, the relative expanded uncertainty of the molar concentration of zinc is 8.6 %.The developed procedure is intended to establish the metrological characteristics of reference materials for the composition of lyophilized blood serum and reconstituted lyophilized blood serum, control the accuracy of the measurement results obtained using other procedures (methods) of measuring similar values, perform high-precision measurements of mass fractions and molar concentrations of copper and zinc in lyophilized blood serum and reconstituted lyophilized blood serum for referee purposes.

The study discusses the issues of improving the accuracy of measuring high hydrogen concentrations in the development of storage materials in the hydrogen energy industry. The purpose of the study was to develop reference materials for calibration of the hydrogen analyzers at high concentrations. The main methods for determining the hydrogen content in materials were analyzed. It was established that the extraction method in an inert gas medium has found the widest application. The main methods for determining the hydrogen content in materials are analyzed, it is established that the extraction method in an inert gas medium has found the widest application. The need for calibration of analyzers on reference materials with a high hydrogen concentration was noted. Reference materials of titanium alloy VT-1-0 with hydrogen concentration up to (4.0±0.1) wt.% have been developed. The optimal parameters for the analysis were selected. On the example of the hydrogen analyzer RHEN602 (LECO, USA), calibration was carried out on the developed reference materials to obtain a calibration dependence. The reliability of the obtained calibration curve with the application of stoichiometric zirconium hydride was estimated. The confidence interval of the resulting calibration curve was ±10 %. It has been established that the calibration on the developed materials makes it possible to analyze materials with a hydrogen content of 0.5 to 4.0 wt.%. The practical significance of the study lies in the development of reference materials that can be applied to calibrate hydrogen analyzers operating on the principle of melting in an inert gas medium at a high hydrogen concentration.