Assessment and investigation of measurement uncertainty of standard samples of substances and materials in physicochemical measurements based on standard test methods

Abstract

The article assessed and investigated the uncertainty of measurements of standard samples of substances and materials in physicochemical measurements based on standard test methods. A general approach to estimating the sources of uncertainty of standard samples is described. Uncertainties from heterogeneity of standard sample material. uncertainty from instability of standard sample characteristic values. uncertainty from method of setting reference value are investigated. Purity of substances is the main parameter that needs to be paid attention to when studying their properties. This is all the more important when it comes to using a pure substance as some approximation to the prototype reference value. since only this unit of seven main units in the International System of Units (SI system) does not have its own standard. In this sense. an important scientific task is the comprehensive study of pure substances for their practical use as benchmarks for comparison in metrological works and analytical research. The main and very important part of the measurement traceability system are materials with certified (certified) content of components and defined uncertainties of these values (standard samples of the approved type). which require pure substances certified at a higher - reference level. i.e. comparison standards.

Scientific basis and practical application of formalization by making decisions taking into account the uncertainty of the results of gas analyzers in the process of comparison

“…Currently, according to clause 6.5 of the ISO/IEC 17025:2017 [7,15,16] standard, metrological traceability of the results of measurements carried out in laboratories should be ensured. Accordingly, it is necessary to calibrate the measurements performed in laboratory conditions and to assess the uncertainty of the measurement results.…”

“…The results of determining the additional error of the measuring instrument are considered positive if the values of the additional error are determined during type approval tests and do not exceed the limits specified in the operating instructions of the measuring instrument for the relevant operating conditions [11][12][13].…”

Kinematic viscosity of liquid media and providing metrological observability of experimental results

“…In particular, about 30 production enterprises are operating in the oil and gas industry. These enterprises produce gasoline, diesel fuel, aviation kerosene, various oils, fuel oil, bitumen, various types of polyethylene, commodity natural and liquefied gas, petrochemical and chemical equipment, cylinders for liquefied gas and other products [2][3][4][5][6][7][8].…”

“…Uzbekistan is a member of the COMET regional metrology organization. One of the main quality and safety indicators is kinematic viscosity [9][10][11][12][13][14][15].…”