Method for assessing measurement uncertainty of water content in cigarettes

Abstract

The invention discloses a method for assessing measurement uncertainty of water content in cigarettes. An equation is established according to the relation between temperatures and humidity of different environments and the quality of cut tobacco before curing, and the variation quantity of cut tobacco before curing is calculated; an equation is established according to the relation between oven temperatures and the quality of cured cut tobacco, and the variation quantity of the cured cut tobacco is calculated; the measured water content and the standard deviation of the cured cut tobacco are taken as independent variables and substituted into an uncertainty model, and an uncertainty calculation value of the water content in a laboratory is obtained. The sensitive coefficient is calculated by use of partial derivatives and the correlation quantity is calculated by the aid of covariance. By use of the model, temperatures and humidity of different environments, water content of different samples and water content uncertainties under different oven temperature fluctuations can be calculated in different laboratories; the method has the characteristics of being low in cost, high in efficiency, simple and convenient to implement, high in practicability and the like, and uncertainty results of water content of cigarettes can be rapidly and accurately obtained. The method is applicable to assessment of other water content uncertainties similar to those of the measurement model and can overcome existing uncertainty assessment defects.

Description

technical field [0001] The invention belongs to the technical field of uncertainty evaluation, and in particular relates to a method for evaluating the measurement uncertainty of the moisture content of cigarettes. Background technique [0002] Laboratory accreditation is equivalent to the mutual recognition agreement signed by laboratory accreditation agencies between countries, so as to reduce repeated inspections, eliminate technical barriers to trade, and promote international trade. [0003] ISO-IEC17025:2005 "Accreditation Criteria for Testing and Calibration Laboratories" is an international standard for laboratory accreditation and a standard for China National Accreditation Service for Conformity Assessment to evaluate whether a laboratory can pass laboratory accreditation. This standard requires laboratories to evaluate the measurement uncertainty of the parameters tested, and laboratories that do not have this capability will be issued non-conformity items and ris...

AI Technical Summary

Problems solved by technology

During the detection of moisture content in cigarettes m 1 、m 2 They are all weighed with the same balance, and considering the correlation of the two parameters will inevitably involve the calculation of covariance, which is another difficulty for most laboratories, so many laboratories will use it when evaluating the measurement uncertainty. Use "assume no correlation" to ignore correlation, resulting in incomplete assessment results

The existing evaluation literature on measurement uncertainty is based on the environmental conditions, instruments, and single samples of the own laboratory. Other laboratories cannot effectively learn from it. Each laboratory needs to do a lot of experiments and method derivation, resulting in great difficulty and waste

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