Breath tests in domestic and foreign medicine are recognized as an effective and safe way to identify pathogens in the gastrointestinal tract, in particular the Helicobacter Pylori bacteria. At the end of the 20th century, a urease breath test was introduced into clinical practice to diagnose diseases of the gastrointestinal tract; it was based on the use of urea labeled with a stable isotope 13C ( 13C-urease breath test). The essence was to measure the delta value of the ratio of carbon and oxygen isotopes in exhaled air.

Over decades of clinical practice of using this test, a wealth of experience related to the diagnosis of diseases caused, including by the Helicobacter Pylori bacteria has been accumulated. A significant amount of knowledge has also been accumulated in terms of metrological support of the carbon and oxygen isotope delta in exhaled air.

The article describes the procedure and results of developing a development of a measurement standard of carbon and oxygen isotope delta in exhaled air, implemented within the R&D a/c No. «Sistema-2020-М» at the D. I. Mendeleyev Institute for Metrology (VNIIM). The authors presented the theoretical study, test methodology, their sequence and results. The article also contains a report on the international comparisons CCQM-P204 “Isotope ratios of CO2 (δ13VPDB and δ18VPDB) in pure CO2” with the application of the measurement standard developed by VNIIM. The metrological characteristics of the measurement standard obtained during the comparisons correspond to the most accurate measurements of the ratio of carbon and oxygen isotopes, which guarantees the recognition of the measurement results at the international level. Considering the high demand for breath tests in medical practice and obvious prospects of this type of diagnostics, further research will be aimed at creating a State Primary Standard for the delta value unit of the ratio of isotopes of carbon, oxygen, hydrogen based on the created measurement standard and the development of certified reference materials of the ratio of isotopes of carbon, oxygen, hydrogen in liquid, solid, and gaseous media, including for the purpose of replacing foreign-made materials.

Cycle weighing is used by metrologists around the world to eliminate drift in comparator readings when comparing the mass of reference weights. Various types of cycles and their descriptions are given in the International Recommendation on legal metrology OIML R111-1-2004 adopted in the Russian Federation as a national standard. They consider cycles under the assumption of linear drift of comparator readings. The article discusses weighing cycles that eliminate nonlinear drift of the comparator. Drift models are proposed in the form of exponential and multinomial laws, which are characterized by a fast dependence of readings at the beginning of the cycle and a slower one at the end of the cycle. The derivation of formulas for the difference between the mass of the verified and the original standard according to four comparator readings at equal time intervals is given. The formulas consist of two components: the first coincides with the formula for linear drift, and the second plays the role of a correction for the drift deviation from linearity. The formulas are also correct for linear drift, since in this case the second components become zero. Estimates of the differences in the mass of the compared weights, taking into account the nonlinearity of the comparator drift, make it possible to estimate the measurement uncertainty for linear and nonlinear drift and become relevant with a constant increase in weighing accuracy, especially when comparing high-precision mass standards.

A new multielement certified reference material of tungsten concentrate (GSO 11541–2020) – wolframitehubnerite concentrate (hard-alloyed), KVG(T) was developed. Its metrological characteristics were established via results of interlaboratory experiment. The analytical results were obtained at the testing laboratories of 13 scientific and manufacturing organizations of Russia, Belarus, Kazakhstan, and Uzbekistan using single-element chemical analysis methods (gravimetric, spectrophotometry, atomic absorption spectrometry, etc.), as well as modern multielement methods (atomic emission spectrometry with arc discharge or inductively coupled plasma, inductively coupled plasma mass spectrometry, X-ray fluorescence spectrometry). The mass fraction values for ten elements certified; for eleven elements recommended; and for 39 elements, as well as hygroscopic and crystallization water, are given as information data. This CRM is intended for certification and validation of single and multielement methods, as well as quality assurance in analysis of the ores and products of their processing in mining, metallurgical, and chemical industries and in scientific research. The information potential of GSO 11541–2020 is higher than that of imported reference materials.

Mammoth ivory is in demand in the jewelry industry, folk crafts and in the manufacture of cosmetics. This unique natural resource is an alternative to the prohibited extraction of ivory. It is fundamentally important for consumers to identify the raw material unambiguously as mammoth ivory and to accurately determine the grade of the material.

The article presents the results of a study, which resulted in the development of a reference materials set of open porosity of the mammoth ivory. The reference materials are cylinders with an outer diameter of 30 mm and a height of 30 mm. Certified values of open porosity were determined by gas pycnometry. Reference materials are intended for certification of measurement methods and control of the accuracy of measurement results of open porosity of mammoth ivory in laboratory conditions. Reference materials can be used for various types of metrological control if the metrological characteristics of reference materials correspond to the established requirements.

The research materials are of an applied nature for a number of economic sectors where mammoth ivory is used as a raw material. Reference materials of mammoth ivory are in demand in materials science, biology, geology, and other natural sciences, and in expert activities to determine the authenticity of products made from mammoth ivory. The article may also be of interest to students and teachers of natural sciences in higher education, as well as anyone interested in artifacts of ancient fauna.

Color metrology is steadily developing in the interests of fundamental and applied science, improving industrial production processes. The author considers the problem of ensuring metrological traceability of color measurements under natural conditions.

Digital image colorimetry methods demonstrate good linearity and precision in relatively small application ranges in studies of same type and mainly non-luminous objects. For complex scenes with a wide range of brightnesses, nonlinear functional color rendering models are used that are focused on visual perception, peak brightness of the monitor and reference viewing conditions, which complicates the processing of measurement results and reduces a confidence interval.

The described method of measuring the chromaticity coordinates of an object by its digital image is based on tensor calculus and consists of multiple registration of an object and sets of reference samples with different exposure times, building calibration dependencies forming a multidimensional colorimetric scale in color space and determining chromaticity coordinates as points of intersection of color tensors with the plane of the color locus. In order to ensure accuracy and reliability of the measurement results in the software and hardware environments, a validation study of the performance indicators of this method was carried out, one of which is linearity. An experiment based on comparing the developed method with the reference measurement method showed the effectiveness of the developed wide-range measurement method with good linearity (correlation coefficient R=0.97… 0.99, residual relative standard deviation s0≈1–2%) when adjusting from the subjective factor and display device.

The experimental materials may be useful to metrologists solving problems of determining the metrological traceability of the color of digital images in media. The article will be of interest to a wide range of readers with professional interests related to the colorimetry of digital images.

Metal coatings provide products with the necessary technical characteristics; in particular, they increase corrosion resistance and protect against mechanical abrasion. The application of metal coatings is a promising direction and is widely used in mechanical engineering, metallurgy, and other industries. Therefore, studying the properties and improving the technology of applying metal coatings is a significant and sought-after line of activity for metrology researchers. The needs of industry in the field of monitoring the parameters of single-layer and single-component coatings in the Russian Federation are fully satisfied. At the beginning of this study, the Federal Information Fund for Ensuring the Uniformity of Measurements provided a comprehensive list of reference materials of surface density and thickness of single-layer onecomponent coatings that were tested using the State Primary Standard for units of surface density and mass fraction of elements in coatings GET 168-2015. The needs for testing, verification, and calibration of instruments for measuring surface density, thickness, and chemical composition of multilayer and multicomponent coatings remained not fully met, which became the starting point for this research.

The research presented in the article was carried out in order to develop methods for determining the surface density and mass fraction of elements for multilayer and multicomponent coatings on GET 168-2015. At the same time, the problem of developing a set of reference materials of surface density and mass fraction of elements in two-layer and two-component coatings for metrological support of the corresponding measuring instruments was solved.

The article fully reveals the content of the work to improve metrological support for measuring surface density, thickness, and mass fraction of elements in coatings, taking into account the needs of industry in the field of monitoring coating parameters and the variety of measurement tasks that are constantly expanding.