Improving the accuracy of indirect and relative measurements of electric variables

A method of improving the accuracy of indirect and relative measurements of electric variables based on the use of stochastic converters in which the functions of the reference measure and the sampling step are separated is described. Algorithms for estimating the relative statistical error of indirect and relative measurements are presented. Translated from Izmeritel'naya Tekhnika, No. 6, pp. 40–46, June, 1998.     

Special aspects of the assurance of accuracy in measurements of coating thicknesses

Factors underlying the difficulty of assuring high accuracy in measurements of the thickness of coatings are investigated, specifically the enormous diversity of coating and base materials with different physical properties, the large number of influencing variables, lack of unification in the interpretation of the concept of coating thickness, insufficient localization of measurements on the part of present-day thicknesses gauges, the broad range measurements, and small absolute errors.Translated from Izmeritel'naya Tekhnika, No. 9, pp. 23–25, September, 1995.     

Generalization of the problem of determining the accuracy of direct measurements for achievement of given accuracies in indirect measurements

Using a general statement of the problem, we consider determination of the accuracy required in direct measurements to achieve a given accuracy of indirect measurements related to the direct measurements by some known relationship. A solution to the problem is stated as a theorem and corollaries. Examples are presented to illustrate how the solution obtained here can be applied in concrete cases. Translated from Izmeritel'naya Tekhnika, No. 1, pp. 8–12, January, 1997.     

Minimization of error in indirect measurements

We pose the problem of minimizing the error in indirect measurements; the solution of this problem reduces to nonlinear programming. Under certain conditions, the results we obtain make it possible to increase the accuracy of indirect measurements, to design measuring systems with controlled minimal measurement error, and to control the distribution of resources in order to minimize error.Translated from Izmeritel'naya Tekhnika, No. 12, pp. 17–19, December, 1994.     

Calculation of the temperature of a heat-transmitting surface from the results of indirect measurements

The problem of the identification of the non-stationary temperature regime of a heat-transmitting wall surface from the results of measurements at an inner point of the body or at a heat-insulated surface is considered. The basis for this method is the joint application of Lavrent'ev regularization and the method of imaginary frequency responses. The given approach enables one to obtain an expression in a form convenient for calculations.Kuban' State Technological University, Krasnodar, Russia. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 68, No. 1, pp. 156–159 January–February, 1995.     

Guaranteed accuracy in electrical measurements

Conclusions It will be easier to provide the necessary accuracy in electrical measurements if researches are performed on additional switched compensation for high-voltage measuring transformers, with subsequent modification of the standards for such transformers. This would eliminate excessive consumption of materials in making measurement transformers and also in the leads connecting them to the recording instruments.At the same time, adjustments are needed to the standards as regards the scale and periods of the check on such transformers.Translated from Izmeritel'naya Tekhnika, No. 1, pp. 77–78, January, 1975.     

Systematic errors in indirect liquid-mass measurements in vessels

The discussion concerns the indirect methods of measuring liquid mass governed by GOST 26976-86. When there are uneven features in the density, flow speed, or vessel area of cross section, one gets a methodological error, which needs to be considered in correcting the mass.Translated from Izmeritel'naya Tekhnika, No. 7, pp. 23–25, July, 1993.     

Some aspects of the uncertainty of a measured quantity and the uncertainty of measurements in thermometry

The use of the main concepts of the international document Guide to the Expression of Uncertainty in Measurement to estimate the uncertainty of temperature measurements is considered. Particular attention is devoted to the sequence of analyzing the accuracy of measurements: a clear definition of the measured quantity and an analysis of the method of measurement used and of the accuracy of the instruments employed for a correct and complete determination of the components of type B uncertainty. Examples of the estimation of the uncertainty of temperature measurements for standard and working measuring instruments are presented.Translated from Izmeritelnaya Tekhnika, No. 9, pp. 38–41, September, 2004.     

New proposal for uncertainty evaluation in indirect measurements

This paper deals with the uncertainty evaluation in indirect measurements. The attention is mainly paid to measurement models whose input quantities are modeled as correlated random variates. Moving from a past proposal related to the use of the unscented transform to overcome key limitations of current guide to the expression of uncertainty in measurement recommendations in the presence of the input quantities modeled as uncorrelated random variates, the authors are going to present a new proposal capable of extending the advantages of the cited transform when correlated input random variates are also concerned. The new proposal is, in particular, addressed to nonlinear and/or nonanalytical measurement models. After describing the key features and implementation issues of the proposal, the results obtained in a number of tests on simulated and actual measurement data are given, which assess its reliability and effectiveness.     

Silver-induced enhancement of thiochrome-based peroxide measurements

Thiamine is presently one of the most attractive substrates used for sensitive fluorometric measurements of peroxides. Thiochrome (TC), a highly fluorescent product, is formed in enzyme-mediated oxidations. It is assumed that H(2)O(2) is nearly quantitatively converted to TC. The reaction cannot differentiate H(2)O(2) from many other peroxides such as methylhydroperoxide (MHP); to perform differential measurements, H(2)O(2) can first be selectively destroyed by a suitable catalyst such as MnO(2). In substituting Ag(2)O for MnO(2) to accomplish the selective destruction of H(2)O(2), we achieved the stated objective but were puzzled by a 3-fold increase in the MHP response in the presence of Ag(2)O. It was soon discovered that traces of dissolved Ag(+) and Hg(2+) can dramatically increase the yield of TC in this reaction from either H(2)O(2) or MHP; the normal yield in fact is only 20%. We present here a reaction scheme and kinetic model that adequately describes this behavior and should provide a path to substantially increase the sensitivity of this important assay method.