工作基准铂电阻温度计在0℃—419.527℃范围内的不确定度的分析

本文给出了0℃-419.527℃分温区内工作基准铂电阻温度计的检定装置的不确定度的评定，本文的分析结果可用于该温区内使用工作基准铂电阻温度计测温结果的不确定度分析。     

工作基准铂电阻温度计在0℃～41 9.527℃范围内的不确定度的分析

本文给出了 0℃～ 4 19 5 2 7℃分温区内工作基准铂电阻温度计的检定装置的不确定度的评定。本文的分析结果可用于该温区内使用工作基准铂电阻温度计测温结果的不确定度分析。     

标准水银温度计不确定度评定

新修订的JJG 161-2010《标准水银温度计》检定规程已经颁布实施,作为检定工作用温度计的标准器,标准水银温度计不确定度的评定尤其重要.本文以50℃为例,分析了分度值为0 1℃的标准水银温度计扩展不确定度,并给出-30～300℃范围标准水银温度计的扩展不确定度.     

(0～419.527)℃一等标准铂电阻温度计检定结果的不确定度评定

按照JJF 1059.1-2012《测量不确定度评定与表示》的要求,对工作在(0～419.527)℃温区的一等标准铂电阻温度计检定结果的不确定度进行评定.包括电测设备引入的标准不确定度分量、标准铂电阻温度计在水三相点、锌凝固点、锡凝固点处阻值的标准不确定度分量,并最终计算电阻比的合成标准不确定度.     

标准铂电阻温度计测量结果不确定度评定

本文以最常用的温度段（0-429．527）℃,以一等标准铂电阻温度计检定二等标准铂电阻温度计为例来分析标准铂电阻温度计的测量结果不确定度。     

代替二等标准水银温度计的数字温度计校准结果不确定度评定

二等标准水银温度计在中温测量中占据着重要的地位,由于国际上禁用水银的要求,研究数字温度计代替二等标准水银温度计作为中温测量的标准器变得尤为重要.本文通过对代替二等标准水银温度计的数字温度计校准过程中影响分量的分析,给出其校准结果的不确定度评定.     

二等标准水银温度计示值修正值测量结果的不确定度评定

JJG128-2003《二等标准水银温度计》检定规程中规定二等标准水银温度计是利用水银在感温泡和毛细管内的热胀冷缩原理来测量温度的,结构分为棒式和内标式两种,主要作为检定工作用温度计的标准器,也可用于精密测温。常用温度范围为-30℃～300℃,分度值为0．1℃。文章对其测量结果示值修正值的不确定度进行评定。     

工作用玻璃液体温度计修正值测量值的不确定度评定

本文按照JJG130-2011的规定,对工作用玻璃液体温度计修正值的不确定度进行评定。温度计测试点为0℃、10℃、20℃、30℃、40℃、50℃时,修正值分别为+0.04℃、-0.03℃、-0.04℃、0.00℃、+0.02℃、0.00℃,扩展不确定度U=0.07℃,k=2。     

恒温槽的校准及不确定度的评定

以具体实例分别介绍了以二等标准水银温度计和二等标准铂电阻为标准器校准标准恒温槽的方法,对两种方法进行了比较,并对不同的方法作了不确定度评定:以二等标准水银温度计为标准器在100℃时的扩展不确定度为0.08℃,以二等标准铂电阻温度计为标准器在100℃是的扩展不确定度为0.026℃。     

(0～419.527)℃一等不标确准定铂度电评阻定温度计检定结果的

按照JJF 10591-2012《测量不确定度评定与表示》的要求,对工作在(0～419527)℃温区的一等标准铂电阻温度计检定结果的不确定度进行评定。包括电测设备引入的标准不确定度分量、标准铂电阻温度计在水三相点、锌凝固点、锡凝固点处阻值的标准不确定度分量,并最终计算电阻比的合成标准不确定度。     

平面度误差的不确定度估计方法及取样点数量的确定

主要阐述在工程测量方案设计阶段,如何采用最小二乘法估算被测要素平面度误差的不确定度和如何确定合理的采样点数,即测量设备的单点坐标不确定度已知时,采用理想点坐标估算法,计算不定乘数系数,继而获得被测要素的采样点数量及其最小二乘法平面度误差的测量不确定度.     

Propagation of Uncertainty Due to Non-linearity in Radiation Thermometers

The measurement of the non-linearity of radiation thermometers is important in the realization of ITS-90 above the silver point and in the calibration of primary or secondary radiation thermometers using multiple fixed points both above and below the silver point. A non-linearity function is usually derived, enabling correction of the measured signals. Uncertainties in this non-linearity function propagate to the uncertainty in the determination of an unknown temperature. Since the same non-linearity function is used both during calibration and in subsequent use of the thermometer, there is a high degree of correlation between the uncertainties in the corrected calibration signals and the corrected in-use signals. While these correlations obviously lead to zero uncertainty at the calibration points, it is difficult to determine the correlation coefficients for temperatures away from these points. This article sets out a mathematical framework, based on interpolation theory, for propagating the uncertainty due to non-linearity in which correlation is easily included. The method is illustrated for a thermometer realizing ITS-90 up to 3,000°C based on one fixed point (silver, gold, or copper), and also for alternative realization schemes based on two or more fixed points. The total non-linearity uncertainty for the multipoint schemes is considerably lower than for the ITS-90 method. The mathematical framework can also be applied to secondary calibrations below the silver point, where non-linearity is typically more problematic for the detectors used in this temperature range.     

激光跟踪仪测角误差的位移标定法

提出了激光跟踪仪测角误差的位移标定方法,通过在跟踪仪的切向位置上引入标准位移量,根据余弦定理对跟踪仪的角度码盘的误差进行标定.在小位移的情况下,跟踪仪角度的变化量很小,由此引入的非线性误差可以忽略,测角误差可以通过位移误差直接反映出来,当给定的标准位移测量不确定度已知时,其角度标定的不确定度可以直接估算出来.     

Mass Point Leak Rate Technique with Uncertainty Analysis

The mass point leak rate technique is often the methodology of choice for quantifying leak rates as it uses simple elementary measurements, applies to gas systems of low mass, proves effective for low leak rates, and does not rely on test-gas conversions. In this methodology, a number of instantaneous mass measurements are calculated through samples of volume, pressure, gas composition, and temperature measurements over time. A regression analysis of the corresponding mass-time sample set yields the leak rate of the system. A detailed uncertainty analysis is paramount for a complete, experimental characterization of the leak rate and previously was not fully implemented in the mass point leak rate method. Recent advancements in regression uncertainty analysis by propagation of errors afford the ability to quantify the uncertainty with estimates of covariance in the regression results. The mass point leak rate technique with the associated detailed measurement uncertainty analysis offers the ability to quantify both the leak rate and the uncertainty associated with the leak rate value. Detailed herein is the development of the methodology and a detailed uncertainty analysis that includes both precision (repeatability) and bias (systematic) error. Alternative leak rate methods are also discussed for comparison purposes. An example in the methodology is presented.     

压力变送器能力验证过程分析及结果评价

本文介绍了实验室参加CNAS组织的压力变送器校准能力验证活动情况,对本次能力验证过程进行了分析。按照JJF 1059. 1-2012《测量不确定度的评定与表示》以及JJG 882-2019《压力变送器检定规程》,对各校准点的各不确定度分量主要来源进行分析与评定,根据压力变送器校准的测量模型对其合成不确定度进行评定,结合测量数据计算出合成标准不确定度和扩展不确定度。根据参比实验室及参考实验室的能力验证数据,计算En值。数据表明:参比实验室参加能力验证结果为满意。     

提高铂电阻温度计测量精度的方法研究

分析了检定规程对铂电阻温度计的要求,通过研究铂电阻温度计的测温特性,提出了提高铂电阻温度计测量精度的方法,并给出了在温度校准点的测量不确定度.     

A decision-oriented measure of uncertainty importance for use in PSA

For the interpretation of the results of probabilistic risk assessments it is important to have measures which identify the basic events that contribute most to the frequency of the top event but also to identify basic events that are the main contributors to the uncertainty in this frequency. Both types of measures, often called Importance Measure and Measure of Uncertainty Importance, respectively, have been the subject of interest for many researchers in the reliability field. The most frequent mode of uncertainty analysis in connection with probabilistic risk assessment has been to propagate the uncertainty of all model parameters up to an uncertainty distribution for the top event frequency. Various uncertainty importance measures have been proposed in order to point out the parameters that in some sense are the main contributors to the top event distribution. The new measure of uncertainty importance suggested here goes a step further in that it has been developed within a decision theory framework, thereby providing an indication of on what basic event it would be most valuable, from the decision-making point of view, to procure more information.     

Integrated inventory valuation in multi-echelon production/distribution systems

The pressure to reduce inventory has increased as competition expands, product variety grows, and capital costs increase. This investigation addresses the problem of inventory quantification and distribution within multi-echelon supply chains under market uncertainty and management flexibility. This approach is based on an optimisation model emphasising demand uncertainty and the relevant dimensions of network design as number of echelons, lead time, service level, and cost of processing activities. Overstock quantification enables the understanding of inventory level sensitivity to market uncertainty. A comparison among production sites and storage facilities revealed that higher downstream overstock levels decrease upstream echelons of uncertainty exposition. The contribution of this study relies on management's ability to establish inventory targets for each stocking point according to risk exposure and to promote the optimisation of working capital. Overall, this investigation increases knowledge related to the treatment of demand uncertainty in flexible and integrated supply chains     

Measurement uncertainty estimation in real experimental conditions of ultrasonic interferometer manometer established at NPL, India

The National Physical Laboratory, India, has established an ultrasonic interferometer manometer (UIM) as a primary standard in the barometric pressure region. This paper reports the results of the measurement uncertainty of the UIM evaluated under experimental conditions at each pressure point through a software developed and integrated with the existing operating software program. Through the operating software program, an initial estimate of column length using time-of-flight and four predefined ultrasonic frequencies with the help of an exact fractions algorithm is made, but the final pressure is calculated from the measurements made at multiple frequencies. At a particular pressure point, 44 measurements are made at different frequencies, covering two full circles (fringes). The mean of these 44 measurements is taken as the measured pressure to minimize the uncertainty contribution due to systematic phase error. In the present uncertainty evaluation, the standard deviation of this mean is taken into account in estimating the measurement uncertainty in real experimental conditions. The uncertainty thus estimated has been compared with that uncertainty, evaluated theoretically, as per ISO Guide to the Expression of Uncertainty in Measurements. This experimental determination of measurement uncertainty has helped us in making further improvements in the measurement accuracy of the UIM, especially at low-pressure measurements.     

Uncertainty of the Kriss Low Frost-Point Humidity Generator

The KRISS low frost-point humidity generator (LFPG), was developed in 2006 for the frost-point range (?95 to ?40)°C in order to extend calibration capabilities. In this paper, the evaluation of the generator??s uncertainty budget is reported for which each uncertainty component was categorized and estimated by experiment and calculation. The uncertainty of the LFPG depends on the generated frost point, gas flow rate, and change of moisture concentration in transportation. The standard uncertainty of LFPG is less than 32 mK in the frost-point range from ?70?°C to ?40?°C. However, in the lower frost-point range, the uncertainty increases to 137 mK at ?90?°C, and this is mainly due to water adsorption or desorption in the transportation tubing from saturator to hygrometer.