Calibration of On-Board Energy Measurement Systems Installed in Locomotives for AC Distorted Current and High Voltage Waveforms and Determination of Its Uncertainty Budget

Periodic calibrations of Energy Measurement Systems (EMS) installed in locomotives must be carried out to demonstrate the required accuracy established in the EN 50463-2 standard according to European Parliament and Council Directive 2008/57/EC on the interoperability of rail systems within the Community. As a result of the work performed in the “MyRailS” EURAMET project an AC calibration facility was developed consisting of a fictive power source was developed. This fictive power source can generate distorted sinusoidal voltages up to 25 kV-50 Hz and 15 kV-16.7 Hz as well as distorted sinusoidal currents up to 500 A with harmonic content up to 5 kHz or phase-fired current waveform stated in EN50463-2 standard. These waveforms are representative of those that appear during periods of acceleration and breaking of the train. Reference measuring systems have been designed and built consisting of high voltage and high current transducers adapted to multimeters, which function as digital recorders to acquire synchronized voltage and current signals. An approved procedure has been developed and an in-depth uncertainty analysis has been performed to achieve a set of uncertainty formulas considering the influence parameters. Different influence parameters have been analyzed to evaluate uncertainty contributions for each quantity to be measured: rms voltage, rms current, active power, apparent power and non-active power of distorted voltage and current waveforms. The resulting calculated global expanded uncertainty for the developed Energy Measuring Function calibration set up has been better than 0.5% for distorted waveforms. This paper is focused on presenting the complete set of expressions and formulas developed for the different influence parameters, necessary for uncertainty budget calculation of an Energy Measuring Function calibration.

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.

Changes in canal width and angle in curved canals in the resin blocks: pro taper next versus one shape instruments

Objective: To compare the effect of OneShape and ProTaper Next file on the change in canal width and angle of curvature in simulated curved canal in resin blocks. Methods: The quasi-experimental study was conducted at the Aga Khan University, Karachi, from January to March 2018, and comprised endodontic resin blocks that had inbuilt curved canals. These were randomly divided into 2 equal groups and were subsequently prepared using OneShape in group A, and ProTaper Next rotary instrument in group B followed by staining with red and blue ink for comparison of pre- and post-operative images of canals. Standardised photographs were taken along with reference measuring scale. SPSS 22 was used for data analysis. Results: Of the 60 blocks, 30(50%) were in each of the two groups. The mean pre-instrumentation angle of curvature was 32.3±2.13 and 31.0+3.28 degrees for groups A and B. The mean degree of canal straightening post-intervention was 1.5+0.5 and 3.6+1.38 degrees in groups A and B (p<0.001). In terms of canal width changes, OneShape file removed more resin material from the canal walls compared to the ProTaper Next system (p<0.001). Conclusion: ProTaper Next file significantly altered the angle of curvature in the resin block compared to OneShape file, but the amount of material removed from the canal space was significantly higher with the OneShape file compared to ProTaper Next. Key Words: ProTaper Next, OneShape, Nickel-titanium Continuous...

Uncertainty for Radon EEC Calibration System with Alpha Self-Absorption Consideration

The measurement of radon decay products level in dwellings or working places separately is not preferable. The estimation of radon equivalent equilibrium concentration (EECRn) is more simple and quick technique. In this work, the uncertainty of calibration system for radon EEC measurements will present and the reduction will be suggesting. The calibration system for radon EEC measurements was presented and described in previous work with gamma spectrometer as a reference measuring device. The influence of alpha particles absorption in filters materials and filter efficiency taken into account. The measurements of EECRn by gamma spectrometry and improved alpha radiometry are in good agreement and the systematic shift between average values is observed and resolved. The total standard uncertainty of EECRn measurements with gamma spectroscopy is 3.8 %. 71 % of this total uncertainty value is related to the uncertainty of the count rate at full absorption peak with gamma spectroscopy. If the time between the end of sampling and gamma spectroscopy measurements reduced to 2000 s not 4000 s, this value will reduce to 1.6 % and the total standard uncertainty of EEC will be 2.6 %.

Total haemoglobin – a reference measuring system for improvement of standardisation

BackgroundTotal haemoglobin (Hb) concentration in blood belongs to the most requested measurands, and the HiCN method (hemiglobincyanide) is accepted as a reference. Although the reaction principle is clearly characterised, measurement conditions and settings are not consistently defined, some of them influencing the results. An improvement of standardisation is the object.MethodsAfter method optimization, measurement results between different calibration laboratories (CL) were compared with each other and also with results of the National Metrology Institute of Germany (PTB), with target values of certified reference material, within the RELA scheme, and to >1500 results from routine laboratories.ResultsOverall deviations between three CLs were ≤0.5% (n = 24 samples) in a measurement range of 20 g/L to 300 g/L. A CV of 0.4% was determined in pooled blood (1 year long-term imprecision, 99.0%–101.1% recovery of the mean). For selected measurements (n = 4 samples) the PTB participated without significant differences to three CLs, and no significant differences were observed comparing CLs to certified values of reference materials. The expanded measurement uncertainty (probability 95%) was estimated as 1.1%.ConclusionsA reference measuring system, comprising measuring instruments and other devices, including reagents and supply, to generate reference measurement values for total Hb concentration of high accuracy and low measurement uncertainty is presented. Measurement parameters are investigated and defined. The reference measuring system is ready to offer service to EQA providers and to the IVD industry for certifying control materials or calibrators.

THE ENHANCEMENT OF METROLOGICAL SUPPORT THE COATING THICKNESS MEASUREMENTS

The article shows an improved hierarchy scheme in the field of coating thickness measurements, which was revised due to inclusion to Federal Information Fund for Ensuring the Uniformity of Measurements more than a hundred new types of Russian and foreign thickness gauges based on of different operating principles. The range of measurements has expanded and accuracy has been improved. It is shown that about 40 % of the approved types of thickness gauges are measuring instruments of foreign production. For responsible groups of materials (nickel on steel and nickel on bronze), only foreign coating thickness gauges are used. To improve the unity of measurements of the coatings thickness, it was necessary to expand the measurement ranges of the reference measuring standards and thickness gauges from 0 to 120 000 microns, as well as the introduction of new measuring standards borrowed from other hierarchy schemes. The article provides the necessary reference measuring standards and thickness gauges, methods for transmitting a unit of length, measuring ranges and measurement errors.