This paper considers issues related to the development of the vacuum system of Watt-balance for the newest Russian Federation primary standard of the kilogram. The authors give a list of the necessary data for the development of the vacuum system of the newest Russian Federation kilogram mass standard, relying on the generally accepted methods of vacuum systems calculation. This paper shows the main stages of theoretical and practical research work conducted in D. I. Mendeleyev Institute for Metrology (VNIIM) with the use of the vacuum mass comparator Sartorius CCL 1007from the composition of the state primary measurement standard of mass unit - kilogram GET 3-2020, aimed at developing a vacuum system for the newest standard of the kilogram - Watt-balance. The presented results of the research allow for the development of the vacuum Watt-balancing system.

The article presents the investigation of a certified reference material (CRM) of the steels mechanical properties. At present traceability of measurement results of mechanical stresses is ensured to the standard of time, but not mechanical stresses, and a metrological approach to ensuring the uniformity of measurements of mechanical stresses requires the development of a basis for comparison.

The aim of the work was the characterization and certification of standard samples of a special form, traceable to SI units-force and length, intended for transferring a unit of magnitude of mechanical stresses to measuring instruments that implement a temporary method of acoustic type of nondestructive check based on the phenomenon of acoustoelasticity. The article discusses the key stages of the development of reference materials: selection of the source material for reference materials; study of the homogeneity of the source material; carrying out experimental studies with the use of reference device (the state standard unit of strength of the 1st category) and establishing the metrological characteristics. As a result of type approval tests CRM was registered in the State Register of CRM’s as GSO 11544-2020/11545-2020. The certified characteristics of the CRM are proportional limit mechanical stress σ_pl; proof strength σ₀₂ (plastic extension 0,2 %); tensile strength σ_в; modulus of elasticity E. Limits of the relative error of the certified values at a confidence level of 0,95 do not exceed 12 %. The authors believe that the CRM of the mechanical properties of steels GSO 11544-2020/11545-2020 will provide metrological traceability of the results of measurements of mechanical stresses by measuring instruments that implement the by acoustic type of nondestructive check, when using the GSO as a basis for comparison in the verification scheme.

At present, there are practically no reference materials for values characterizing the beneficial effect of the use of petroleum products, which reduces the efficiency of the metrological assurance processes for petroleum products testing. In particular, certification by the method of monitoring technical characteristics is an ineffective procedure for a number of motor sets and benches. It is necessary to assess the stability of such testing equipment relative to the s TABLE characteristics of any substance or material.

Reference materials of motor fuels performance properties must comply with the requirements for the adequacy of the chemical composition of RM and motor fuels and guaranteed reproducibility of the values during the subsequent manufacture of a new batch of the reference material. In addition, reference materials should reproduce the values characteristic of a particular brand of commercial motor fuel or production technology.

It was necessary to develop a method for justification of the composition of reference materials of motor fuels performance properties to meet the above requirements. The method includes the following stages: determination of the characteristic hydrocarbon composition of commercial motor fuels, selection of individual hydrocarbons of various groups, verification of their composition and basic physical and chemical properties, study of the most characteristic values of the investigated performance property and establishment of requirements for a possible measurement range of the certified value, measurement of the certified value for each individual hydrocarbon to be added to the composition of the reference material, development of a mathematical model «The composition of the mixture of individual hydrocarbons - The value of the motor fuel performance property» using experimental planning methods, calculation of the values of the concentrations of individual hydrocarbons in the mixture, providing the required certified value, experimental verification of the value of the certified characteristic of the performance property for the mixture with calculated values of the concentrations of individual hydrocarbons, correction of the calculated concentrations of individual hydrocarbons.

The efficiency of the developed method is shown by the example of justification of the reference material composition of jet fuel chemical stability.

At present, radiation technologies are most commonly applied for sterilization of medical supplies and irradiation of food products. The results of radiation treatment cannot be fully verified by subsequent non-destructive testing. Therefore, irradiation processes and equipment used for radiation treatment should be subject to mandatory validation and certification. In this paper, we present the results obtained during process validation of radiation-technological installations based on electron accelerators by investigating absorbed dose in irradiated products.

The author’s article presents information on the study of the stability of main indicators of fertility (mobile forms of phosphorus and potassium, organic matter) in different types of soil. Experiments were carried out on state reference materials selected in different soil-climatic zones, within 12-30 years since the date of reference material certification. It has been established that different types of soil preserve sufficient stability of the content of mobile forms of phosphorus and potassium, organic matter in reference material provided that reference materials were kept in storage in dry room in removal from the installations that create vibration, with the lack of vapor steams and the relative humidity of the air not higher than 70 %.

The results of the studies of stability of main characteristics of soil fertility (mobile forms of phosphorus and potassium, organic matter) allow us to recommend a guaranteed storage period of reference materials of soils certified for these indicators during 10 years.

The article is devoted to the comparison of two approaches to determining the purity of metal salts on the example of a complex in composition object - flotation potassium chloride. The results of determining the mass fraction of the main component (potassium chloride) in flotation potassium chloride obtained by direct (using the coulometric titration method with correction for anions titrated with the determined chloride ion and an excess of cations) and indirect (according to the scheme 100% minus the amount of impurities with regard to their species) methods. It is shown that direct and indirect methods give well consistent results: (96.08 ± 0.17) % and (96.11 ± 0.12) %, respectively. Also, the measurement results obtained using the standard installations considering the uncertainty are well consistent with the certified value of the mass fraction of potassium chloride (96.11 ± 0.11) %, obtained based on an interlaboratory experiment in laboratories that perform measurements in accordance with GOST 20851.3. The feature of the direct and indirect methods implemented in this work is the construction of a model of the chemical composition of the analysed object based on a priori and experimental data using two basic principles when summing up the content of impurities: the conditions of material balance and the principle of electroneutrality.