Electrical transformers are a key element in the process of distributing electricity from the producer to the final consumer. The reliability of electrical transformers is ensured through systematic monitoring of the structural condition using chemical analysis of fuel (transformer) oil used for electrical insulation and cooling of transformers. The working life of energy oil and paper insulation can be assessed by evaluating the content of antioxidant additive (ionol) and furan derivatives (furfuryl alcohol, furfural, 2-acetylfuran and 5-methylfurfural). The article provides a critical analysis of methods for measuring ionol and furan derivatives in oils. In particular, it has been established that the most widely used methods for the identification of ionol and furan derivatives are liquid and gas chromatography methods with preliminary isolation of analytes based on the principles of liquid/solid-phase extraction. At the same time, the need for matrix reference materials with established metrological traceability was identified for metrological support of methods for measuring the content of ionol and furan derivatives in oils.

   Therefore, the purpose of this study was the development of a certified reference material (CRM) for the composition of fuel oil.

   The technology for producing such a CRM makes it possible to prepare the material with the required concentrations of analytes. The article describes the sequence of preparation of a CRM batch and presents the conclusions of studying the stability and between-bottle homogeneity of the material. The given calculation of the standard uncertainty for the certified value of the CRM from the characterization method, heterogeneity, and instability of the material in accordance with GOST ISO Guide 35–2015 deserves attention. The metrological traceability of certified values of the CRM to the unit of value «mass fraction of a component» reproduced by the State Primary Standard of units of mass (molar) fraction and mass (molar) concentration of organic components in liquid and solid substances and materials based on liquid and gas chromatography-mass spectrometry with isotope dilution and gravimetry (GET 208–2019). The competence of the study is confirmed by the fact that the CRM was recognized as GSO 12232–2023.

   In the Russian Federation, obligations to comply with radiation safety apply to all legal entities and individuals whose activities may result in the irradiation of people and the environment. Protection from dangerous ionizing radiation is a combination of legislative, economic and engineering measures. Part of this system is metrological support for the activities of economic entities. The State Verification Schedule for means measuring radionuclide activity flux and flux density of alfa-, beta-particles and photons of radionuclide source has undergone a number of changes. In particular, it establishes the role of reference materials as one of the main means of transferring units of specific activity and activity of radionuclides from the State Primary Standard for the units of radionuclide activity, specific activity of radionuclides, flux of alpha, beta particles and photons of radionuclide sources GET 6–2016 to working standards and measuring instruments. The changes introduced into the State Verification Schedule require the development of new types of reference materials in the field of ionizing radiation. This article raises the main issues of development and approval of reference materials of radionuclide activity based on a mixture of radionuclide solutions and a liquid scintillator. A detailed explanation of the choice of radionuclides is presented, a brief description of the characterization method is given, and metrological characteristics of the developed reference materials are described. The reference materials developed and described in this article act as a new type of working standards in accordance with GOST 8.033-2023. The authors outlined a concept for the further development and application of new types of reference materials in the field of measuring the activity and specific activity of alpha- and beta-emitting radionuclides. The new types of reference materials described in the article will fully cover the need for means of verifying devices whose operating principle is based on detecting ionizing radiation using a liquid scintillator.

   The use of force measurements standards ensures testing of load and force sensors designed for measuring and studying large loads in rocket science, nuclear power plant construction, and testing of structural materials. The article provides an overview of the State Primary Standard of force GET 32–2011 of the Russian Federation in the range up to 1 MN, and also analyzes international experience in the field of reproduction of the unit of force with a value above 1 MN. The range of reproduction and composition of loads of the deadweight machine EU-100 from the composition of the State Primary Standard of force GET 32–2011 of the Russian Federation, deadweight machine of the Physical-Technical Federal Institute (PTB, Germany), deadweight machine of the National Institute of Standards and Technologies, deadweight machine of the Fujian Institute for Metrology (FPIM, China) and the deadweight machine of the Korea Research Institute of Standards and Science (KRISS, Republic of Korea) were assessed. The article is of scientific and practical interest to specialists in the field of reproduction of the unit of force of large values. The generalized experience can become the basis  for research in the field of improving the standards of force. The review is also addressed to teachers and students of specialized disciplines of higher education.

   The appearance on the market of measuring equipment of multiphase flowmeters used in the oil and gas industry to measure the amount of extracted hydrocarbons directly at wells without preliminary separation and performing the function of operational accounting raised the question of their metrological support in accordance with the requirements of regulatory documents of the sphere of state regulation in this field of measurements. His decision was to create a reference base, the basis of which was the State primary special standard for units of mass flow of gas-liquid mixtures GET 195-2011 and a verification scheme for measuring multiphase flow rates, regulated by GOST 8.637-2013. When transmitting units of volume and mass flow of a multiphase mixture with the required accuracy, the main problem is the difficulty of reproducing and maintaining stability of several flow parameters at once – mass flow and content of liquid components (water and oil simulator) and volume flow of the gas phase. It should also be borne in mind that test programs for the purpose of approving the type of multiphase flow measuring instruments, as well as verification and calibration methods, provide for changing the modes of reproduction of a gas-liquid mixture, covering the measurement ranges of multiphase flowmeters. Such standards used in practice represent a very complex measuring system consisting of storage tanks for components, supply pumping and compressor units, control equipment, mixers and separators, measuring instruments for the physical parameters of multiphase flow components and an automated control system. Given the high cost of multiphase standards, when creating them, effective methods and methods should be used to reproduce the flow of a multiphase mixture with specified parameters, as well as to make a fairly rapid transition to the next mode provided by the program or methodology, which will reduce the time and production costs for the procedure of transferring units of measurement from the standard to the working measuring instrument. This article describes a method for reproducing the flow rate of a gas-liquid mixture according to the original technological scheme introduced during the development of the 1st category standard. Constructive solutions are presented that increase the efficiency of the liquid component separation apparatus to increase the dosing accuracy, as well as expand the range of reproduction of the flow rate and parameters of the multiphase flow, ensuring the consistency of the composition of the liquid mixture at a given regime. An original rational method of compressing and maintaining the pressure of the gas phase is described, which allows you to quickly switch to the next mode, confirmed by the results of experimental studies of the standard.

   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.

   An in-depth investigation into CaO-based carbonation reaction kinetics for CO₂ sorption is being conducted using simultaneous thermal analysis (STA), with the application of advanced thermogravimetric and differential scanning calorimetry techniques. Utilizing advanced thermal analysis system for real-time monitoring of simultaneous measurements of mass changes and thermal effects are conducted, ensuring precision and versatility in data acquisition. The study explores the intricacies of the non-isothermal carbonation process across a wide range of temperatures, shedding light on the temperature-dependent trends in reaction rates. Innovative statistical methods, combining regression techniques and Arrhenius equation, are employed to determine energy and reaction kinetics. The sensitivity of carbonation process to varying pressure conditions is meticulously examined in the study, providing pivotal discernment for optimization of reaction parameters across diverse applications. The integration of STA with statistical modeling alongside systematic analysis of temperature-dependent trends and pressure-order relationships not only enhances the understanding of CO₂ capture efficiency but also improves the robustness and accuracy of the findings. Furthermore, meticulous cross-validation with existing studies provides a critical evaluation of the experimental approach’s precision and limitations. This study enhances understanding of CaO carbonation kinetics, providing practical implications for carbon capture processes and contributing to sustainable industrial processes.

   This section continues to publish information on the types of standard samples that were approved by Rosstandart Orders, starting from May 2024 and including August 2024, in accordance with the Administrative Regulations, which were amended according to Rosstandart Order No. 1404 of August 17, 2020 "On Amending the Administrative Regulations for the Provision of the Federal Service for Technical Regulation and Metrology for Approving the Type of Standard Samples or Type of Measuring Instruments" (approved by Order of the Federal Agency for Technical Regulation and Metrology dated November 12, 2018 No. 2346). The amendments were made in order to implement Federal Law No. 496-FZ of December 27, 2019 "On Amending the Federal Law "On Ensuring the Uniformity of Measurements". From 01.01.2021, types of standard samples are approved by Orders of Rosstandart in accordance with the Order of the Ministry of Industry and Trade of Russia No. 2905 of August 28, 2020, which entered into force, "On approval of the procedure for testing standard samples or measuring instruments for the purpose of type approval, the procedure for approving the type of standard samples or type of measuring instruments, amending information about them, the procedure for issuing certificates of approval of the type of standard samples or type of measuring instruments, the form of certificates of approval of the type of standard samples or type of measuring instruments, requirements for the approval marks of the type of standard samples or type of measuring instruments and the procedure for their application." More detailed information on the approved types of RMs can also be found in the public domain in the Federal Information Fund for Ensuring the Uniformity of Measurements on the website of the FGIS Rosstandart - https://fgis.gost.ru/ – in the section "Approved types of standard samples".

   In accordance with the requirements of the Order of the Ministry of Industry and Trade of Russia dated 28. 08. 2020 No. 29051 (came into force on 01. 01. 2021), the decision to amend the information regarding the validity period of the approved type of standard samples (hereinafter referred to as the SS) is made by the Federal Agency for Technical Regulation and Metrology (Rosstandart) based on an application from the copyright holder of the approved type of SS. The application shall be accompanied by a conclusion based on the results of the review of the design, technological and (or) technical documentation of the SS, confirming that no changes were made to the design, technological and (or) technical documentation of the SS and the information about the approved type of SS contained in the Federal information fund for ensuring the uniformity of measurements corresponds to the technical documentation of the SS. When making changes to the information regarding the validity period of the approved type of SS, the application shall be submitted at least 30 working days before the expiration of the approved type of SS. The decision to amend the information on the approved type of CO is made by Rosstandart in the form of an order extending the validity period for the next 5 years from the expiration date of the approved type of CO. The CO of the approved type, the information on which has been amended in terms of the validity period of the CO, starting from mid-2024, are presented in the table.