S. Duta
For ensuring the traceability and uniformity of measurement results, the main objectives of national metrology in chemistry are to calibrate and verify measuring instruments, to evaluate the uncertainty of measurement results, to intercompare the analytical results etc. The concept of traceability has developed recently in chemical measurements, thus, an attempt to implement the principles of metrological traceability especially by appropriateness calibration using the composition certified reference materials (CRMs), are underlined. The paper presents some aspects and practices in the field...
XVI IMEKO World Congress
· 2000
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G. D’Antona, L. Di Rienzo, R. Ottoboni
On the market are available many data acquisition systems not specifically designed for measurement application. When used for this particular purpose, although the digital stage would be adequate, the analog front-end is often source of unacceptable uncertainty. A new opportunity offered by modern powerful digital processor hosted on data acquisition systems consist in employing the processor for identify and compensate the non-ideal behavior of the analog front-end in real-time. The effectiveness of this method is greatly conditioned by the accuracy that can be achieved in the...
XVI IMEKO World Congress
· 2000
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G. Crotti, G. Farina, L. Rege
The thermal and mechanical stresses resulting from a short-circuit fault in an electric circuit strongly depend on the circuit power factor. For this reason, the IEC standard related to short-circuit test indicates, for each current range, the value of the power factor with a defined tolerance. A method for the measurement of the power factor based on the analysis of the digitally recorded short-circuit current is briefly described. The method is checked by applying it to the evaluation of the power factor measurement value and uncertainty in simulated test conditions. Attention is focused...
XVI IMEKO World Congress
· 2000
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S. Cierpisz, A. Heyduk
On-line nuclear meters have been in use in the coal industry for many years. They have been utilised for coal quality monitoring, in the control systems for coal blending, or for separating coals in the heavy media separation process. Their operation is based on the scattering or the absorption of incident gamma radiation, and the derived density or ash value is the result of a time-averaged measurement. In this paper, dynamic models of ash monitors have been presented and discussed. The analysis of monitors with constant time of measurement shows that it is possible to determine the optimal...
XVI IMEKO World Congress
· 2000
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K. Chrzanowski, R. Matyszkiel, M. Szulim
Rules of evaluation of uncertainty as a measure of measurement accuracy are presented in the well-known "Guide to the expression of uncertainty in measurement". There are a few examples of uncertainty calculations in literature. However, all these examples refer to the case when the output quantity is determined on the basis of known input quantities by an analytical formula. In this paper a case when the output quantity is determined on basis of known input quantities by solving numerically a set of equations is discussed. It was shown that the rules recommended in the Guide cannot be used...
XVI IMEKO World Congress
· 2000
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S. Caldara, S. Nuccio, C. Spataro
In this paper the problem of characterisation, in terms of uncertainty, of the measurement digital instruments performances, based on the typical architecture of PC bus plugged data acquisition boards is considered. According to the GUM the measuring model and the various sources of uncertainty have been taken into account and the law of uncertainty propagation has been applied. Then theoretical and numerical analyses of combined uncertainties are carried out obtaining formulas for the estimation of the standard uncertainty of the measurement result of various hardware and software blocks of...
XVI IMEKO World Congress
· 2000
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M. Buzoianu
Metrology, in general, and issues such as traceability and measurement uncertainty, in particular, are increasingly demanded when checking the safety of a wide range of food and agricultural products, in chemical manufacturing, environment protection, clinical chemistry as well for regulatory purposes. In many chemical quantitative analysis, the evaluation of measurement uncertainty requires the practician to look closely at all possible sources of uncertainty. Among them, data provided in calibration and correlation between the input quantities call for insight based on experience and...
XVI IMEKO World Congress
· 2000
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M. Borovicka, A. Janac, N. M. Durakbasa
The quality of production depend from accuracy of manufacturing machinery too. The topic describe new calculation method of accuracy manufacturing machinery in manufacturing process. The accuracy of production in manufacturing process express the quality of production. When we want know what accuracy we achieve at manufacturing we must know calculation accuracy of manufacturing machinery. Uncertainty measured parameter of production in concrete manufacturing process depend from accuracy of manufacturing machinery.
XVI IMEKO World Congress
· 2000
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V. Batagelj, J. Bojkovski, I. Pušnik
In the proposed paper a possibility of automation of calibration of liquidin- glass thermometers is discussed. Temperature readings are taken with the use of a measuring system that consists of a standard calibration facility, the video camera, and the personal computer that executes the program for image processing and analyses. Once the reading of temperature is extracted from an acquired image, this value can be passed to any other data processing, which includes the comparison with the values from the reference thermometer and determination of total uncertainty. Data achieved in this way...
XVI IMEKO World Congress
· 2000
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V. Y. Aibe
The mathematical model of the measurement in the “Guide to the Expression of Uncertainty in Measurement” is Y = f ( X 1 , X 2 ,..., X N ), where Y is the meansurand and X 1 , X 2 ,..., X N are the influence quantities. The expanded uncertainty U is obtained by U = k u c ( y ), where u c ( y ) is the combined uncertainty and k is the coverage factor that depends on the effective degrees of freedom. The value of effective degrees of freedom is obtained from the Welch-Satterthwaite formula. It is assumed that there isn’t correlation between influence quantities. In this paper will be presented...
XVI IMEKO World Congress
· 2000
· Download