Determination of the Error in Transferring of Length Unit’s Size when Measuring the Nanoparticles’ Diameter Using an Analyzer of Particles’ Differential Electrical Mobility

The quality of nanomaterials and nanotechnologies is largely determined by the stability of the applied technologies, which, to a large extent, depend on the constancy of particle sizes. In this regard, metrological problems arise that are associated both with measuring the dimensions of the microstructure of aerosols, suspensions and powders, and with ensuring the uniformity of measurements when transferring a unit of a physical quantity from a standard to working measuring instruments. The purpose of this work was to determine and calculate the error in transferring the size of a unit of length when measuring the diameter of nanoparticles.An analyzer of differential electric mobility of particles was determined as a reference measuring instrument for which the calculation was made. It allows the separation of aerosol particles based on the dependence of their electrical mobility on the particle size. In combination with a condensation particle counter, it allows you to scan an aerosol and build a particle size distribution function. This measurement method is the most accurate in the field of measuring the diameters of particles in aerosols, therefore, the error in the transmission of particle size must be set as for a standard.The paper describes the physical principles of measurement by this method and presents an equation for determining the diameter of nanoparticles. Based on this equation, the sources of non-excluded systematic error were identified. Also, an experimental method was used to determine the random component of the measurement error of nanoparticles and to calculate the error in transferring the size of a unit of length when measuring the diameter of nanoparticles.The obtained results will be used for metrological support of standard samples of particle size, ensuring traceability of measurements of aerosol particle counters and for aerosol research.

Test algorithm to confirm the type of modern measuring devices for low absolute pressures and vacuum

The article provides information on the normative documentation applicable in the Russian Federation on the approval procedure of measuring devices, explains the procedure for carrying out tests for approval of the type of vacuum measuring devices at D. I. Mendeleyev Institute for Metrology VNIIM, summarized information about modern high-precision thermal (measuring range (1⋅10-2… 1.08⋅105) Pa, maximum permissible error of a measuring ±(10…50) %) and ionization (specified measuring range (1⋅10-7…1.3) Pa, maximum permissible error of a measuring ±(20…50) %) of vacuum gauges that have been tested for type approval since 2016. The information on the vacuum gauges contained in this article was published in the Federal Information Fund for Ensuring the Uniformity of Measurements.

Correct measurement methodology spatial-energy characteristics of laser beams

A methodology for correct measurements of the spatial and energy characteristics of a laser beam is considered, based on the determination of the initial moments of the spatial intensity distribution in the beam cross section. The classification of radiation fields participating in the measuring process is given: emitted, measured and measured. It is shown that ISO 11146:2005 “Lasers and laser-related equipment. Test methods for laser beam widths, divergence angles and beam propagation ratios, Part 1-3” for measuring the spatial and energy characteristics of laser beams leads to incorrect measurements. This is due to the fact that the recommendations for the application of ISO 11146:2005 do not take into account the dynamic range of the used matrix radiation detectors, and the characteristics of the emitted field of interest to the user turn out to be diverging, which violates the uniformity of measurements. Moreover, the conditions ensuring the convergence of the results are practically impracticable. To solve these problems, it is proposed to establish and regulate the lower level of the dynamic range of measurements of the intensity of the used matrix receivers and to consider the spatial and energy characteristics of the emitted field of interest to the user, depending on the set value of the lower level. It is shown that measurements with this methodology become correct and make it possible to compare the characteristics of laser beams obtained by different array detectors. Formulas are given that take into account the effect of the lower level of the dynamic range of the matrix radiation detectors on the measurement result. These formulas should be recommended for inclusion in the updated edition of the national standard GOST R ISO 11146-2008 “Lasers and laser installations (systems). Methods for measuring widths, divergence angles and propagation coefficients of laser beams. Parts 1-3”.

GRAIN DESCRIPTION BY A RANDOMLY INHOMOGENEOUS OPTICAL MEDIUM MODEL FOR THE INTERLABORATORY MATCHING OF VITREOUSNESS MEASUREMENTS

Currently, due to the appearance of instrumental objective methods for determining grain vitreousness, it is possible to ensure the uniformity of measurements of this indicator in a number of laboratories. The article proposes a model for describing grain as an inhomogeneous optical medium and an interpretation of the vitreousness index as a characteristic of light scattering. A method for calculating the parameters of mathematical model and estimating the scattering coefficient using an RGB camera is presented. It is shown that the implementation of the grain vitreousness measurements based on the scattering coefficient makes possible to obtain a satisfactory reproducibility in between-lab measurements.

PROS AND CONS OF PRIORITY OF ELECTRONIC REGISTRATION OF THE RESULTS OF VERIFICATION OF MEASUREMENTS

The article reveals the positive aspects of registering of verification outcomes of measuring tools in electronic form instead of issuing them on paper, as well as possible problems that organizations accredited in the field of ensuring the uniformity of measurements and customers of metrological works and services may face.

METROLOGY APPLICATIONS IN CHEMICAL ENGINEERING: A BRIEF REVIEW

Metrology, while often confused with the science of measuring weather (meteorology), is a very widely used field. Metrology is mainly concerned with (i) establishing the units of measurements, reproducing these units in the form of standards, and ensuring the uniformity of measurements, (ii) developing methods of measurement, analysing the accuracy of methods of measurement, establishing uncertainty of measurement, researching into the causes of measuring errors, and eliminating these. Although as engineers and scientists, we make use of measurement to quantify the physical and chemical properties of objects, and design systems to conform to standards based on unit of measurement, the principles of measurement science (metrology) is not too familiar to most engineers and scientists. The focus of this brief review is to bring to fore the (i) meaning and definitions of metrology, (ii) importance of measurement, and (iii) the importance of metrology applications in chemical engineering and engineering in general. Key words: Metrology, measurement, process control, process development, engineering design.

Determination of precision conditions for measuring relative values in mechanical tests of various materials

The problem of insufficient detail of the requirements for the developed and certified measurement methods used in mechanical testing of various materials is considered. The compatibility of the requirements of metrological support for the results of quantitative chemical analysis and indirect results of mechanical tests for the wear resistance of materials when rubbing against a fixed abrasive is relevant. To ensure the accuracy of measurements, it is proposed to use the grain size of the abrasive material and the rotation speed of the abrasive disk as variable factors. In order to establish the requirements for the metrological characteristics of materials during mechanical tests, in particular, when determining the relative wear resistance, the conditions for precision measurements are justified. The results of a multi-stage experiment-testing of materials for wear resistance with the use of various research and consumables, measuring instruments and testing equipment are presented. The conditions for the organization of the experiment in the case of determining other relative mechanical characteristics of the materials under study for establishing precision indicators in the development of methods of mechanical tests for abrasive wear are proposed and justified. The application of the obtained results will allow developers of mechanical testing methods to establish metrological characteristics of materials in compliance with all the requirements of the State System for Ensuring the Uniformity of Measurements of the Russian Federation.

Approaches to creating a unified information system for metrological support of geographically-distributed complex technical systems

The article is devoted to the problems of improving the efficiency of the system of metrological support for geographically distributed complex technical systems by combining them into a single information space, the need for which is due to trends in digitalization of activities in the field of ensuring the uniformity of measurements.

IMPROVING THE METHODOLOGY FOR METROLOGICAL CERTIFICATION OF TOTAL STATIONS AND LIGHT RANGE FINDERS

To ensure the uniformity of measurements, it is necessary to perform periodic verifications of ge-odetic instruments in accordance with the requirements of the relevant regulatory documents. In relation to total stations and light meters, ensuring the uniformity of measurements should be carried out by conducting annual periodic checks with the use of stationary reference bases of the 2nd or 3rd category, which were previously created in almost all regions of the country. However, to date, only two such bases have been preserved on the territory of the Russian Federation. The reason for this situa-tion was the lack of proper metrological support for the line lengths of the reference bases themselves, caused by the need for organizational measures, the lack of trained specialists, as well as significant financial expenses for field work. In this regard, there was a scientific and technical task of developing a local calibration scheme (LCS) to provide periodic verifications of total stations and light-emitting diodes over the entire range of measured distances, which does not require the creation of stationary reference bases. For this purpose, the LCS scheme is proposed, based on the use of the method of direct distance measurements. Its essence lies in the simultaneous measurement of the selected distances by reference and verified total stations. To do this, a reference total station and a verifiable one are installed on two tripods located next to each other, which measure the same distance. After that, the total stations are swapped and the measurements are repeated. At the end of the measurement, the measured distances are compared with the reference and verified total stations. Then, based on the difference between these distances, a conclusion is made about the accuracy of the de-vice being tested, as stated in the technical data sheet. The results of the implementation of the proposed LCS showed that its scheme provides the accuracy of measurements at the level of the 2nd category reference basis, and the methodology and accuracy of the length unit transmission meets the of regulatory requirements.