Evaluation of Measurement Uncertainty for Water Content Tests in Soil Samples

2013 ◽  
Vol 718-720 ◽  
pp. 984-988
Author(s):  
Zhi Qing Gao ◽  
Nai Qi Shen ◽  
Xu Li ◽  
Zong Yun Shu
Keyword(s):  
Measurement Uncertainty ◽  
Water Content ◽  
Measurement Accuracy ◽  
Soil Samples ◽  
Uncertainty Of Measurement ◽  
Expanded Uncertainty ◽  
Factors Affecting ◽  
Testing Conditions ◽  
Content Determination ◽  
Measurement Results

Measurement uncertainty in the water content test for soil samples is an index for evaluating the reliability of the experiment. It affects the accuracy of some parameters such as porosity and saturation, which are derived from water content. According to the requirements of the standard JJF 1059-1999 Uncertainty Evaluation and Denotation of the Measurement Results, the uncertainty for the measurement results of the water content in soil samples was evaluated. Concerning the characteristics of the water content determination in soil samples, a pail of soil sample was taken as specimen due to its relative homogeneity. The factors affecting the measurement accuracy were discussed. The result shows that the expanded uncertainty of measurement results of the water content in soil samples was 1.6% under the proposed testing conditions.

Estimation of uncertainty in olfactometry

2009 ◽  
Vol 59 (7) ◽  
pp. 1409-1413 ◽  
Author(s):  
T. Higuchi
Keyword(s):  
Measurement Uncertainty ◽  
Interlaboratory Comparison ◽  
Collaborative Study ◽  
Estimation Procedure ◽  
Measurement Model ◽  
Standard Uncertainty ◽  
Expanded Uncertainty ◽  
Collaborative Test ◽  
Measurement Results ◽  
Estimation Of Uncertainty

Estimation of uncertainty in odour measurement is essential to the interpretation of the measurement results. The fundamental procedure for the estimation of measurement uncertainty comprises the specification of the measurement process, expression of the measurement model and all influences, evaluation of the standard uncertainty of each component, calculation of the combined standard uncertainty, determination of a coverage factor, calculation of the expanded uncertainty and reporting. Collaborative study such as interlaboratory comparison of olfactometry yields performance indicators of the measurement method including repeatability and reproducibility. Therefore, the use of collaborative test results for measurement uncertainty estimation according to ISO/TS 21748 and ISO 20988 is effective and reasonable. Measurement uncertainty of the triangular odour bag method was estimated using interlaboratory comparison data from 2003 to 2007 on the basis of the simplest model of statistical analysis, and the expanded uncertainty of odour index ranged between 3.1 and 6.7. On the basis of the establishment of the estimation procedure for uncertainty, a coherent interpretation method for the measurement results will be proposed and more effective and practical quality control of olfactometry will be available.

An Investigation of Various Factors Affecting Measurement Accuracy of the Tekscan Seat Pressure System

1996 ◽  
Vol 40 (20) ◽  
pp. 1036-1040 ◽  
Author(s):  
Hongzheng Lu ◽  
Gang Lin
Keyword(s):  
Measurement Error ◽  
Contact Area ◽  
Contact Time ◽  
Measurement Accuracy ◽  
Time Interval ◽  
Pressure System ◽  
Factors Affecting ◽  
Measurement Results ◽  
Accuracy Of Measurement ◽  
Pressure Measurement System

This study investigated the following factors affecting the measurement accuracy of the seat pressure measurement system made by TekScan, Inc.: (a) contact time; (b) contact area; (c) the amount of force applied on the pressure mat at the time of calibration and at measurement; and (d) the consistency of contact time before calibration and measurement, and the time interval between calibration and measurement. Results show that the above factors significantly affect the accuracy of measurement. The measurement error can be limited by controlling the contact time for both calibration and measurement to 2 minutes, and controlling the contact area and applied force equally at calibration and measurement.

scholarly journals AN INDEPENDENT ASSESSMENT OF UNCERTAINTY FOR RADIOCARBON ANALYSIS WITH THE NEW GENERATION HIGH-YIELD ACCELERATOR MASS SPECTROMETERS

Radiocarbon ◽  
2020 ◽  
pp. 1-22
Author(s):  
A T Aerts-Bijma ◽  
D Paul ◽  
M W Dee ◽  
S W L Palstra ◽  
H A J Meijer
Keyword(s):  
Measurement Uncertainty ◽  
Research University ◽  
High Yield ◽  
Expanded Uncertainty ◽  
Mass Spectrometers ◽  
Actual Measurement ◽  
Measurement Results ◽  
Reference Measurements ◽  
Sample Measurement ◽  
Processing Steps

ABSTRACT The radiocarbon (14C) dating facility at the Centre for Isotope Research, University of Groningen went through a major upgrade in 2017 and this included installation of a MICADAS accelerator mass spectrometer (AMS). In the first 18 months, we performed 4000 sample and 3000 reference measurements. A careful evaluation of those measurement results is presented, to characterize the various sources of uncertainty and to ultimately assign, for every sample measurement, a realistic expanded uncertainty. This analysis was performed on the measurements of secondary references and sample duplicates in various phases of their processing steps. The final expanded uncertainty includes both the 14C measurement uncertainties and uncertainties originating from pretreatment steps. Where the 14C measurement uncertainty includes straightforward uncertainties arising from Poisson statistics, background subtraction, calibration on Oxalic Acid II and δ13C correction, the uncertainties originating from pretreatment steps are based on the spread of actual measurement results for secondary references and sample duplicates. We show that the 14C measurement uncertainty requires expansion, depending on the number of processing steps involved prior to a 14C measurement, by a maximum factor of 1.6 at our laboratory. By using these expansion (multiplication) factors, we make our reported uncertainty both more realistic and reliable.

Uncertainty Analysis for Fiber Permeability Measurement

2005 ◽  
Vol 127 (4) ◽  
pp. 907-911 ◽  
Author(s):  
Chensong Dong
Keyword(s):  
Measurement Uncertainty ◽  
Uncertainty Propagation ◽  
Permeability Measurement ◽  
Parameter Uncertainties ◽  
Factors Affecting ◽  
Sources Of Uncertainty ◽  
Measurement Results ◽  
Simulation Results ◽  
Instrument Accuracy ◽  
Significant Factors

An uncertainty study for fiber permeability measurement is presented in this paper. The sources of uncertainty were identified. This paper focuses on the instrument and environmental uncertainties. The parameter uncertainties of both unsaturated and saturated measurements were estimated based on instrument accuracy limitations and environmental influences. Their influences on the permeability uncertainty were investigated by uncertainty propagation and Monte Carlo simulation. The significant factors affecting the permeability measurement uncertainty were identified. The results show that (1) unsaturated measurement has a higher accuracy than saturated measurement; (2) the significant factors affecting measurement results are pressure and viscosity. Based on the simulation results, the approaches to reduce measurement uncertainty were proposed.

scholarly journals The Evaluation of Expanded Uncertainty of DC Voltages in the Presence of Electromagnetic Interferences using the LabVIEW Environment

2021 ◽  
Vol 21 (5) ◽  
pp. 136-141
Author(s):  
Przemysław Otomański ◽  
Eligiusz Pawłowski ◽  
Anna Szlachta
Keyword(s):  
Direct Measurement ◽  
Measuring System ◽  
Measuring Instrument ◽  
Uncertainty Of Measurement ◽  
Expanded Uncertainty ◽  
System A ◽  
Data Acquisition Board ◽  
Measurement Results ◽  
Virtual Measuring Instrument ◽  
User Friendly

Abstract The paper presents a possible application of integrated LabVIEW environment to the final evaluation of measurement results in direct measurement. The possibilities of presenting and visualizing the uncertainty of measurement results in a convenient and user-friendly form are also discussed. The topics discussed in the paper were presented using a developed application in LabVIEW. The paper discusses the topic of measurement of direct voltages in the presence of strong electromagnetic interferences. These problems are frequently omitted or hardly emphasized. It presents a suitable measuring system, a virtual measuring instrument created in the LabVIEW environment, and the results of tests carried out for an example NI PCI-6221 data acquisition board. The described approach can be applied also in other measurement situations.

scholarly journals Expanded uncertainty evaluation taking into account the correlation between estimates of input quantities

2021 ◽  
pp. 4-8
Author(s):  
Igor Zakharov ◽  
Pavel Neyezhmakov ◽  
Olesia Botsiura
Keyword(s):  
Measurement Uncertainty ◽  
Correlation Coefficient ◽  
Degrees Of Freedom ◽  
Reduction Method ◽  
Standard Uncertainty ◽  
Effective Number ◽  
Expanded Uncertainty ◽  
Wide Range ◽  
Measurement Results ◽  
Processing Of Measurement Results

An expression for estimating the combined standard uncertainty taking into account the observed correlation between the estimates of the two input quantities is given. The Welch – Satterthwaite formula given in the GUM is analyzed. It is shown that the number of degrees of freedom calculated using this formula will vary over a wide range when the value of the correlation coefficient changes, and in some cases it may take an unacceptable zero value. An expression for calculating the combined standard uncertainty by the reduction method is given. It is shown that the number of degrees of freedom in this method does not depend on the value of the correlation coefficient. A formula for calculating the effective number of degrees of freedom taking into account the observed correlation is proposed. The existing expression for calculating the kurtosis of the measurand is analyzed and an expression is proposed for calculating the kurtosis of the measurand in the presence of a correlation between the input quantities. An example of estimation of expanded uncertainty when measuring the coefficient of a pressure transducer using a calibrator is considered. Estimates of the distribution of the measurand, obtained using Monte Carlo simulation, showed that they are closest to the estimates obtained by the kurtosis method. The considered example showed that taking into account the correlation in the processing of measurement results makes it possible to reduce the expanded measurement uncertainty of the converter coefficient by 1.22–1.27 times. Keywords: measurement uncertainty; correlation; effective number of degrees of freedom; method of kurtosis

UNCERTAINTY OF THE MEASUREMENTS RESULTS OF THE CHEMICAL COMPOSITION AND ITS METHODS ASSESSMENT

2021 ◽  
pp. 84-91
Author(s):  
F.N. Karachevtsev ◽  
◽  
A.F. Letov ◽  
A.V. Slavin ◽  
◽  
...  
Keyword(s):  
Standard Sample ◽  
Measurement Methods ◽  
Measuring Instrument ◽  
Uncertainty Of Measurement ◽  
Expanded Uncertainty ◽  
Regulatory Documents ◽  
Measurement Results ◽  
Final Measurement ◽  
Repeatability And Reproducibility ◽  
The Difference

An explanation of the difference between the uncertainty and the error of the measurement results, which is in the approach to their assessment, is given. The standard and expanded uncertainty are estimated taking into account the uncertainty at each operation to transfer the size of a physical quantity from a standard (standard sample) to a measuring instrument and during measurements. The error is estimated based on the variance of the final measurement. Methods for evaluating the uncertainty of measurement results are given depending on regulatory documents, metrological characteristics, measurement methods, such as indicators and limits of repeatability and reproducibility.

scholarly journals Mental Experiment in Metrology and Representation of Measurement Uncertainty in a Complex Form

2018 ◽  
pp. 47-49
Author(s):  
V. Chalyy
Keyword(s):  
Measurement Uncertainty ◽  
Thought Experiment ◽  
Complex Form ◽  
Standard Uncertainty ◽  
Measurement Information ◽  
Uncertainty Of Measurement ◽  
Total Uncertainty ◽  
The Real ◽  
Technical Procedure ◽  
Measurement Results

The essence of the thought experiment and its use in metrology for evaluating and presenting measurement results are studied. An imaginary experiment has a hypothetical-deductive structure, carried out on the basis of the developed program, plan-scheme, is based on experience and is based on the real laws of the phenomena under study and does not go beyond the boundaries of empirical preconditions. The term «uncertainty» of measurement is considered in three aspects: quantitative knowledge of objects of the real world, the technical procedure for obtaining pragmatic measurement information, evaluation of the measured information for making informed decisions and risk management. An analyzed of the shortcomings of exis­ting methods to assess the components of measurement uncertainty, based on the specific features of the GUM concept. In this concept, all components of measurement uncertainty are grouped abstractly into two categories - A and B without sufficient justification of the classification criteria. A method for classifying the components of uncertainty based on a real or mental experiment is proposed, and the results obtained are referred to as real (standard) uncertainty «and» imagi­nary (standard) uncertainty». The total uncertainty is considered as a complex value and is calculated on the basis of orthogonal vectors of the results of real and imaginary experiments. The proposed interpretation of the uncertainty of measurement gives a better understan­ding of the nature of uncertainty, simplifies entries and calculations.

Sign in / Sign up

Export Citation Format

Share Document