Measurement Standards of Ukraine for Gas Volume Flow Rate at Pressures of 1 MPa to 5 MPa

The characteristics of the primary measurement standards of the volume gas flow rate at high pressure developed in various countries are considered. A hierarchical scheme for gas flow measuring instruments and a corresponding metrological traceability chain are presented. Described is a PVTt method, on which the primary standards of gas flow rate used in the USA, France, Japan, and Taiwan are based. The need to create in Ukraine primary measurement standards of gas flow rate at high pressure covering different parts of the total flow rate interval from 0,3 m3/h to 1800 m3/h at a pressure of 1 MPa to 5 MPa is substantiated. Metrological traceability of gas flow measurements is realized through a sequence of critical flow Venturi nozzles, which play a role of the reference flow rate material measures. The standards might be used to calibrate the primary reference Venturi nozzles of the most common 0,1 mm to 8 mm diameters. The characteristics and parameters of the standards are determined. By their metrological and technical characteristics, the standards will correspond to the state-of-the-art level. According to the programme of developing the measurement-standard facilities in Ukraine, in 2019 the primary standard PVTt-65 was created and work had started on the development of the primary standard PVTt-1800 and the working standard PE-5400. A detailed study of the metrological characteristics of the measurement standards will be the topic of further work.

Planning and Reporting Method Validation Studies Print Email. A Supplement to the Eurachem Guide «The Fitness for Purpose of Analytical Methods»

Ukrainian translation of The Fitness for Purpose of Analytical Methods - A Laboratory Guide to Method Validation and Related Topics (2nd ed.), which was published in 2014, is offered. Since Document publication the Method Validation Working Group has identified areas where extra guidance would be appropriate. This extra guidance has been prepared in the form of supplementary documents, which should be used in conjunction with the Guide. Original Document is published on the Euracem website. https://www.eurachem.org/index.php/publications/guides/planning-validation-studies

Problems of the measurement management systems evaluation for business entities on voluntary basis

Questions concerning evaluation and confirmation of measurement capabilities for business entities on a voluntary basis are considered. Existing problems in executing this kind of activity by enterprises, which are regulated by the Ministry of Economy of Ukraine (metrological centers) as well as other enterprises and organizations. Causes of impossibility to issue certificates on compliance of the measurement management systems with requirements of DSTU ISO 10012 as a result of providing the above-mentioned operations are determined. The ways of solving the determined questions for metrological centers are proposed.

Alternative approach to international comparisons

According to the authors point of view, absence of the accepted by metrological society software based on simple and understandable and at the same time flexible and multipurpose mathematical apparatus is one of the restrictions on the way to arrangement of international comprehensive comparisons with expanded group of participants (hereinafter — comprehensive comparisons). General methodology of measurements adjustment by the least square method (LSM) may be used for this mathematical apparatus. Software named «Metrology Network» is defined. It was used for repeated processing of measurement results during the key comparisons of EURAMET.L-K1.2011 «Measurement of gage blocks by interferometer». «Metrology Network» software allowed to estimate simply and quickly systematic measurement error components of the gage blocks length measurement by each laboratory. They are called multiplicative and additive measurement standards degrees of equivalence. «Metrology Network» allowed to estimate strictly by LSM the uncertainties of length measurement. Additive degrees of equivalence are considered substantial and constant characteristics of the measurement standards for many laboratories. Thus, they coincide for steel and ceramic gage blocks. These additive degrees of equivalence may be used as corrections in the process of calibration or as the reference values for further comparisons. The simulation of measurement results for international comprehensive comparisons with complicated structure was provided. For 120 laboratories divided into 12 groups, totally 2442 length measurements of the steel or ceramic gage blocks were provided. They form together 24 sets of 8 gage blocks and provide 24 loops of comparisons. Necessity to provide the adjustment by the least square method is caused by the fact that two subgroups from each group of three laboratories took part in two different related loops of comparison. As a conclusion, «Metrology Network» software easily managed this complicated task of adjustment. It allowed us to calculate each of 120 measurement standards additive degree of equivalence relative to the averaged zero for all measurement standards and multiplicative degree of equivalence relative to the averaged measurement unit.

Comprehensive analysis of former and new methods on conformity establishment of measuring instruments

Taking into account five-year experience in measuring instruments conformity assessment with technical regulations requirements, gradual shift from the former system of testing and control to the new methods is considered according to the new Law of Ukraine «On metrology and metrological activity», which is harmonized with European Laws on metrology. Advantages of the system for measuring instruments conformity assessment with technical regulations requirements were determined and analyzed for instruments manufacturers and customers.

The measurements results adjustment by the Least Square Method

The method for processing of the measurement results obtained from Comite International des Poids et Measures (CIPM) Key, Regional Metrology Organizations (RMO) or supplementary comparisons, from the proficiency testing by interlaboratory comparisons and the calibrations is proposed. It is named by authors as adjustment by least square method (LSM). Additive and multiplicative parameters for each measuring standard of every particular laboratory will be the results of this adjustment. As well as the parameters for each artifact. The parameters of the measurements standards are their additive and multiplicative degrees of equivalence from the comparison and the estimations of the systematic errors (biases) from calibrations. The parameters of the artifacts are the key comparisons reference value from the comparison and the assigned quantity values from the calibrations. The adjustment is considered as a way to solving a problem of processing the great amount of homogeneous measurements with many measuring standards at a different comparison levels (CIPM, RMO or supplementary), including connected problems. Four different cases of the adjustments are considered. The first one is a free case of adjustment. It was named so because of the fact that none of participants has any advantage except their uncertainties of measurements. The second one is a fixed case of adjustment. Measuring results of RMO and supplementary comparisons are rigidly linked to additive and multiplicative parameters of measuring standards of particular laboratories participated in CIPM key comparisons. The third one is a case of adjustment with dependent equations. This one is not so rigidly linked of the new comparisons results to previous or to some other comparisons as for fixed case. It means that the new results of comparisons are influenced by the known additive and multiplicative parameters and vice versa. The fourth one is a free case of adjustment with additional summary equations. In that case certain checking equations are added to the system of equations. So, the sum of parameters multiplied by their weights of all measurement standards for particular laboratories participated in comparisons should be equal to zero.

The calibration and uncertainty evaluation by elementary measurement models

Nature has often made necessary things simple (elementary) and complicated ones unnecessary. This can be applied to measurement models of the large amount of working measurement standards and working measuring instruments. Nevertheless, if measurement model is elementary, it does not mean that it is primitive. It should be formulated according to the sufficiency, mathematical completeness and correctness principles. The attempt to formulate models according to the mentioned principles is introduced. Models are called elementary, as measurement result is function of one or two homogeneous measured quantities. Thus, measurement result is a single reading of the measurement standard or measuring instrument or average value of several readings, or bias as the disparity between readings of the calibrated measuring instrument and measurement standard. Notwithstanding the elementary measurement models simplicity, many variants of solutions are obtained in the process of the measurement result uncertainty evaluation by these models. Publication demonstrates how to choose the best uncertainty evaluation from many variants of solutions depending on whether single readings or average of several readings is included to measurement model. The best choice of the measurement model depends on resolution of the indicating measuring instrument. Moreover, the best choice depends on the measurement standard used for calibration, which is material measure or measuring instrument and depends on the calibration object: material measure or measuring instrument.

Specifics of biomedical parameters estimation of human organism respiratory subsystem

Offered approach to the functional state of organism estimation as holistic system with the complex of interrelated, interactive, mutually affecting functional subsystems of homeostatic type, which may be described as statistically stable biomedical parameters complex. Offered integral index helps to estimate the respiratory subsystem condition using basic organism indexes. Information model of the biomedical parameters transformation was developed. Input quantities uncertainty analysis of the mentioned subsystem information model of the organism gave an opportunity to increase probability of making correct decision concerning the biological objects condition. Methodic of the respiratory subsystem condition estimation was developed and possible conditions range was determined.

AC phase controlled bridges – ground and main properties

This work describes the new approach to the improving of the accuracy of the bridge impedance measurements. By this approach, the bridge balance in a wide impedance range uses the control of the phases of the aggregate of the cardinal signals only. The optimal structure and algorithm of the control of this aggregate of the cardinal signals is determined. Using this approach accurate impedance meters with low size and price are developed. In the limit, this approach gets us the possibility to develop fully integrated impedance meters. Report shortly describes universal impedance meters with phase control, their balance and calibration algorithms.

Interlaboratory comparisons of calibration results of a multifunctional calibrator of electrical quantities

Article is dedicated to organization and conduct of the calibration results of reciprocal interlaboratory comparisons for the multifunctional calibrator of electric quantities: DC voltage, AC voltage, DC current and AC current. The interlaboratory comparisons of electric quantities measurement instruments calibration results are represented. Evaluation of the laboratory calibration results bias is provided using the modified criterion. Analysis and conclusions concerning participating laboratory competence are provided.