Determination Of Measurement Uncertainty Research Articles

Towards efficient application-dependent dimensional measurements with computed tomography: optimized reduction of measurement duration using continuous scan mode: experimental investigations

Abstract. Due to the complex physical and technical relationships in dimensional X-ray computed tomography measurement technology, the precise influences on the measurement result are still not fully understood. A deeper understanding of these influences is essential in order to improve the measurement accuracy and economy of computed tomographic measurement systems. In addition, this enables better numerical determination of measurement uncertainties, which is also a topic of current research. Two factors that have a significant influence on the lead times are the scan mode and the number of projections per measurement. In this article, these factors are investigated experimentally using a calibrated workpiece, and the influence of the workpiece position on the measurement result is also examined. It can be shown that the workpiece position has a considerable influence on the quality of the measurement, especially in the case of a continuous scan. The results show a vast potential for application-dependent reduction of lead times.

Methodologies for model parameterization of virtual CTs for measurement uncertainty estimation

X-ray computed tomography (XCT) is a fast-growing technology for dimensional measurements in industrial applications. However, traceable and efficient methods to determine measurement uncertainties are not available. Guidelines like the VDI/VDE 2630 Part 2.1 suggest at least 20 repetitions of a specific measurement task, which is not feasible for industrial standards. Simulation-based approaches to determine task specific measurement uncertainties are promising, but require closely adjusted model parameters and an integration of error sources like geometrical deviations during a measurement. Unfortunately, the development of an automated process to parameterize and integrate geometrical deviations into XCT models is still an open issue. In this work, the whole processing chain of dimensional XCT measurements is taken into account with focus on the issues and requirements to determine suitable parameters of geometrical deviations. Starting off with baseline simulations of different XCT systems, two approaches are investigated to determine and integrate geometrical deviations of reference measurements. The first approach tries to iteratively estimate geometric deviation parameter values to match the characteristics of the missing error sources. The second approach estimates those values based on radiographs of a known calibrated reference object. In contrast to prior work both approaches only use a condensed set of parameters to map geometric deviations. In case of the iterative approach, some major issues regarding unhandled directional dependencies have been identified and discussed. Whereas the radiographic method resulted in task specific expanded measurements uncertainties below one micrometre even for bi-directional features, which is a step closer towards a true digital twin for uncertainty estimations in dimensional XCT.

Reference object for traceability establishment in X-ray computed tomography measurements of fiber length in fiber-reinforced polymeric materials

X-ray computed tomography (CT) is an advanced non-destructive measuring technique that enables holistic three-dimensional measurements of outer as well as inner geometries and micro-scale features. In the field of fiber-reinforced polymeric (FRP) materials, CT can overcome the limitations of conventional methods typically based on time-consuming and destructive operations used for the measurement of fiber orientation and length, which are two characteristics that have a great impact on physical and mechanical properties of FRP parts. This work specifically addresses the CT measurement of fiber length, which is particularly complex because – differently from the fiber orientation analysis – it requires the individual fibers to be properly identified and segmented. Moreover, the traceability of such measurement has not been achieved yet. This work investigates an experimental methodology for traceability establishment and measurement uncertainty determination, based on the substitution approach. In particular, a task-specific reference object, including a selection of fibers with different lengths and configurations, was designed, manufactured and calibrated for the purpose.

Liquid Chromatography High-Resolution Mass Spectrometry in Forensic Toxicology: What are the Specifics of Method Development, Validation and Quality Assurance for Comprehensive Screening Approaches?

The use of high-resolution mass spectrometry (HRMS) has increased over the past decade in clinical and forensic toxicology, especially for comprehensive screening approaches. Despite this, few guidelines in this field have specifically addressed HRMS issues concerning compound identification, validation, measurement uncertainty and quality assurance. To fully implement this technique, certainly in an era in which the quality demands for laboratories are ever-increasing due to various norms (e.g. the International Organization for Standardization's ISO 17025), these specific issues need to be addressed. This manuscript reviews 26 HRMSbased methods for qualitative systematic toxicological analysis (STA) published between 2011 and 2021. Key analytical data such as samples matrices, analytical platforms, numbers of analytes and employed mass spectral reference databases/libraries as well as the studied validation parameters are summarized and discussed. The article further includes a critical review of targeted and untargeted data acquisition approaches, available HRMS reference databases and libraries as well as current guidelines for HRMS data interpretation with a particular focus on identification criteria. Moreover, it provides an overview on current recommendations for the validation and determination of measurement uncertainty of qualitative methods. Finally, the article aims to put forward suggestions for method development, compound identification, validation experiments to be performed, and adequate determination of measurement uncertainty for this type of wide-range qualitative HRMSbased methods.

Simultaneous determination of particle size, velocity, and mass flow in dust-laden supersonic flows

The particle mass concentration and -mass flow rate are fundamental parameters for describing two-phase flows and are products of particle number, -size, -velocity, and -density. When investigating particle-induced heating augmentation, a detailed knowledge of these parameters is essential. In most of previous experimental studies considering particle-induced heating augmentation, only average particle mass flow rates are given, without any relation to measured particle sizes and -velocities within the flow or any indication of measurement uncertainty. In this work, particle number, individual particle sizes, and velocities were measured in a supersonic flow by means of shadowgraphy and particle tracking velocimetry (PTV). The goals are to determine measurement uncertainties, a particle velocity-size relation, and the spatial distribution of number, size, velocity, and mass flow rate across the nozzle exit. Experiments were conducted in a facility with a nozzle exit diameter of 30 mm, at Ma∞ = 2.1 and Re∞ = 8.2e7 1/m. Particles made of Al2O3 and up to 60 µm in size were used for seeding. Particle mass flow rates up to 50 kg/m2 s were achieved. It is shown that an additional correction procedure reduced common software uncertainties regarding shadowgraphy particle size determination from 14% to less than 6%. Discrepancies between calculated particle velocities and experimental data were found. In terms of spatial distribution, larger particles and a higher mass flow rate concentrate in the flow center. The determined particle mass flow rate uncertainty was up to 50% for PTV; for shadowgraphy, it was less than 17%.Graphical abstract

Novel dedicated reference standards for the qualification of radiography-based computed tomography simulation software

This contribution presents a set of largely novel reference standards specially designed for testing different important physical effects and functionalities of radiography-based computed tomography (CT) simulation software. These standards were developed within the scope of the German cooperation project “CTSimU – Radiographic Computed Tomography Simulation for Measurement Uncertainty Evaluation” [1] and serve as tools for the basic qualification of the sufficient physical correctness and required features of simulation software of CT-based coordinate measurement systems (CMSs) via the analyses either of 2D projection images only or of full CT scans. The results serve as input to the German standardisation committee for the development of a new national VDI/VDE guideline in the series VDI/VDE 2630 dealing with the basic qualification aspect of CT simulation software and shall lay ground for the measurement uncertainty determination of dimensional measurements using CT.

Virtual indoor-GPS for measurement uncertainty determination in reconfigurable environments

In Line-less Mobile Assembly Systems, the mobilization of assembly resources and products enables rapid physical system reconfigurations to increase flexibility and adaptability. The clean floor approach discards fixed anchor points, so that assembly resources such as mobile robots and automated guided vehicles transporting products can adapt to new products and form new processes. Associated challenges are accurate spatial referencing between mobile resources to meet assembly tolerance requirements. There is a need for more accurate positioning data to locate and navigate mobile assembly resources. An indoor-GPS, as a distributed large-scale metrology system, is able to cover a wide shop floor area and to obtain positioning data with uncertainties in the submillimeter range. The measurement uncertainty of such a system depends on the spatial distribution of the transmitters and the receiver positions. To be able to validate positioning tolerance requirements of an assembly process, measurement uncertainties must be determined. Virtual measurements simulate measurement processes and model dependencies between the environment and the metrology system. This work presents a novel approach for a virtual indoor-GPS to determine measurement uncertainties during a process and to evaluate the measurement process capability. Experiments show the validity of the virtual indoor-GPS which can be used as a planning tool for metrology system setups within Line-less Mobile Assembly Systems.

Feature selection for measurement models

PurposeIn the determination of the measurement uncertainty, the GUM procedure requires the building of a measurement model that establishes a functional relationship between the measurand and all influencing quantities. Since the effort of modelling as well as quantifying the measurement uncertainties depend on the number of influencing quantities considered, the aim of this study is to determine relevant influencing quantities and to remove irrelevant ones from the dataset.Design/methodology/approachIn this work, it was investigated whether the effort of modelling for the determination of measurement uncertainty can be reduced by the use of feature selection (FS) methods. For this purpose, 9 different FS methods were tested on 16 artificial test datasets, whose properties (number of data points, number of features, complexity, features with low influence and redundant features) were varied via a design of experiments.FindingsBased on a success metric, the stability, universality and complexity of the method, two FS methods could be identified that reliably identify relevant and irrelevant influencing quantities for a measurement model.Originality/valueFor the first time, FS methods were applied to datasets with properties of classical measurement processes. The simulation-based results serve as a basis for further research in the field of FS for measurement models. The identified algorithms will be applied to real measurement processes in the future.

An analytical study to determine prohibited anabolic residues in red meat tissue using LC-MS/MS system

Hormones used for various purposes in animal breeding are not only important for animal health but also human health and thus meat and meat products need to be checked frequently for hormone residues. As the methods of detecting hormone residues in food samples are difficult and time-consuming, the present study was conducted with the aim of fast and practical determination of prohibited anabolic agents in red meat using LC MS-MS system. For this purpose, the QuEChERS method, which is widely used in pesticide and veterinary drug residue analysis was performed as below. Accordingly, (i) more polar solvent (Acetonitrile) was used in the sample preparation step and (ii) dispersive solid-phase solution was used instead of the solid phase extraction solution in the solution cleaning step. Furthermore, (iii) different groups were injected together in a single injection to analyze different types of anabolic substances with LC-MS/MS in the multi-component analysis phase. After the validation and determination of measurement uncertainty, 20 commercially available red meat tissues were analyzed, and the findings were compared to the literature. It was concluded that the applied method was found to be fast and reliable in the detection of prohibited anabolic agents in red meat tissue.

Measurement Uncertainty in Voltage Coefficients for Compressed-Gas Capacitor Based on a Simplified Tilting Method

High-voltage compressed-gas capacitor is a type of precision equipment commonly used in high voltage laboratories. The voltage dependence of capacitance, in other words, the voltage coefficient of capacitance, is an important factor to ensure the measurement accuracy of capacitors. The simplified tilting method derived from PTB, which provides a solution for measuring the voltage coefficient of the high-voltage capacitor with compressed-gas coaxial cylindrical electrodes structure. However, it is not an easy work for most laboratories. In order to evaluate the voltage coefficient based on the simplified tilting method, a special experimental platform was developed. The high-voltage capacitor installed on the platform can be tilted and rotated at high voltage and be remote-controlled. Base on the developed platform, the voltage coefficient of a 350 kV high-voltage capacitor was measured. In order to verify, it was re-measured by the direct measurement method with a dummy high-voltage capacitor, and before that, the voltage coefficient of the dummy capacitor was calibrated with a near zero-voltage-coefficient capacitor. The results show a good agreement, the consistency of the measurement results is better than 1.2×10^-6 between the two methods. Furthermore, the evaluation of measurement uncertainty in the voltage coefficient determination of capacitor based on simplified tilting method is introduced in detail. The evaluation results show that the expanded uncertainty is significantly better than 2.0×10^-6, k=2.

Measurement Uncertainty – its Place in Education Studies

The article deals with the issue of uncertainty. The importance of this issue in education studies is indicated. Selected ideas and models from the foundations of measurement theory and probability theory are presented and related to selected circulating opinions, as well as an example of the determination of measurement uncertainty.

A model of confocal microscopy measurements combining empirical and physical properties

Virtual measuring instruments are useful tools in surface topography measurement and can be applied for the prediction of measuring results and the determination of measurement uncertainty. For optical measuring instruments, often computationally expensive ray-tracing algorithms are applied. Other models provide an approximation of the transfer behavior based on techniques from signal processing or physical considerations of the instrument setup. For confocal microscopy, we suggest the application of a hybrid model which combines a linear filter model with limitations caused by physical properties of the measuring instrument. The application of the comprehensive model and the estimation of measurement uncertainty based on the instrument characteristics are presented. The results are in good compliance with experimental data and the model requires very few computing effort. An easy-to-use approach to implement the corresponding models for a specific measuring instrument is presented.

Application of Metrological Approaches in the Design of Calibration Equipment for Verification of Float Level Gauges

Abstract The paper deals with a scientific approach for an increase of accuracy of measurement and possibilities for automation of the standard equipment for calibration and verification of float level gauges. They are applied in high-capacity fuel storage tanks, and they are intended to measure the level of stored liquid hydrocarbons. In the submitted paper, we describe original approaches towards metrological control of float level gauges. Firstly, we present and describe the current ways of control by means of the standard equipment of the first generation with a precision caliper and manual measuring wire with the application of modern scientific and developing processes. A new system, whose design is based on research and development, represents a fully automated measuring system which utilizes the incremental optical encoder with a precision graduated ring and a rewind pulley. The paper deals with the issue of a design of the standard equipment and its measurement system from the standpoint of metrology and construction. Based on scientific procedures, we solve reasons of errors in measurement and their reduction on concrete components of the measurement system. The result is that, following the scientific approach and mathematical description of the determination of measurement uncertainties, constructors are able to design suitable tolerances for the production of components of measuring devices and related materials and technologies.

Method Validation and Measurement Uncertainty Determination of Ethoxyquin and Antioxidant Activity in Paprika Seasonings and Paprika Sauces Frequently Consumed in South Korea

In this study, we investigated and validated a method for the quantitative analysis of ethoxyquin in paprika seasonings and sauces, which are frequently consumed in South Korea. Using this analytical method, we were able to confirm the presence of ethoxyquin under optimized high-performance liquid chromatography/photodiode array (HPLC-PDA) and liquid chromatography with tandem mass spectrometry conditions. Additionally, the antioxidant activity of ethoxyquin was assessed using the American Spice Trade Association values and its residual levels in paprika seasoning samples. The HPLC-PDA limits of detection and quantification for ethoxyquin were found to be 0.26 and 0.79 μg/mL, and 0.33 to 1.00 μg/mL, and the recoveries of ethoxyquin ranged from 86.75 to 101.70%, with relative standard deviations ranging from 0.31% to 3.59%. These results indicated that the analytical method in this study should be appropriate for the quantitative analysis of ethoxyquin in paprika seasoning and sauce matrices.

Modelling complex measurement processes for measurement uncertainty determination

PurposeMeasurement uncertainty is present in all measurement processes in the field of production engineering. However, this uncertainty should be minimized to avoid erroneous decisions. Present methods to determine the measurement uncertainty are either only applicable to certain processes and do not lead to valid results in general or require a high effort in their application. To optimize the costs and benefits of the measurement uncertainty determination, a method has to be developed which is valid in general and easy to apply. The paper aims to discuss these issues.Design/methodology/approachThis paper presents a new technique for determining the measurement uncertainty of complex measurement processes. The approximation capability of artificial neural networks with one hidden layer is proven for continuous functions and represents the basis for a method for determining a measurement model for continuous measurement values.FindingsAs this method does not require any previous knowledge or expertise, it is easy to apply to any measurement process with a continuous output. Using the model equation for the measurement values obtained by the neural network, the measurement uncertainty can be derived using common methods, like the Guide to the expression of uncertainty in measurement. Moreover, a method for evaluating the model performance is presented. By comparing measured values with the output of the neural network, a range in which the model is valid can be established. Combining the evaluation process with the modelling itself, the model can be improved with no further effort.Originality/valueThe developed method simplifies the design of neural networks in general and the modelling for the determination of measurement uncertainty in particular.

Spot size and detector unsharpness determination for numerical measurement uncertainty determination

As the experimental measurement uncertainty evaluation for computed tomography is currently an expensive and timeconsuming task, numerical uncertainty evaluation (according to GUM Supplement 1) using a virtual CT is a promising alternative. For this digital twin to simulate accurate measurement results, the virtual CT system needs to be modelled as reallistically as possible using adequate input parameters for the simulation. This paper describes a method for the separated determination of two significant input parameters: focal spot size and detector unsharpness. The method is tested using a wide range of measurement parameters on a Zeiss Metrotom 1500 with different test specimen. It could be shown that the method yields reasonable results for most parameters. In addition, there is a dependence of the focal spot size on the ratio of tube voltage and tube current at constant power. This contradicts the wide-spread rule of thumb that the spot size depends on the tube power only. Indications of a changing focal spot shape at high powers could be detected.

CIE 198‐SP2:2018 Determination of Measurement Uncertainties in Photometry Supplement 2: Spectral Measurements and Derivative Quantities. Vienna: CIE Central Bureau; 2018. ISBN 978‐3‐902842‐11‐4; 78 pages; € 162 (Members of the National Committees of the CIE receive a 66.7% discount on this price) available from the CIE Webshop or from the National Committees of the CIE.

Color Research & ApplicationVolume 44, Issue 1 p. 150-150 PUBLICATIONS BRIEFLY MENTIONED CIE 198-SP2:2018 Determination of Measurement Uncertainties in Photometry Supplement 2: Spectral Measurements and Derivative Quantities. Vienna: CIE Central Bureau; 2018. ISBN 978-3-902842-11-4; 78 pages; € 162 (Members of the National Committees of the CIE receive a 66.7% discount on this price) available from the CIE Webshop or from the National Committees of the CIE. First published: 29 December 2018 https://doi.org/10.1002/col.22328Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume44, Issue1February 2019Pages 150-150 RelatedInformation

Determination of Measurement Uncertainties in Building Acoustics by Interlaboratory Tests. Part 2: Sound Absorption Measured in Reverberation Rooms

Determination of Measurement Uncertainties in Building Acoustics by Interlaboratory Tests. Part 2: Sound Absorption Measured in Reverberation Rooms

Measurement uncertainty of surface roughness measurement

There are several measurement methods to microgeometric examination of the surfaces machined by different cutting processes. At Department of Manufacturing Technology, Institute of Materials and Manufacturing Sciences, Óbuda University it has a traditional contact (stylus) instrument with related software which is widely used in the industrial practice. All measurements such as the surface roughness are characterized by uncertainties which are essential for accurate measurement of the result since the surface quality is characterized by the obtained roughness measurements. The measurement and the characterization of surface roughness and the method of determining measurement uncertainty are standardized. This article describes the determination and analysis of measurement uncertainty for 2D roughness parameters on surfaces prepared with different cutting methods.

Ultrasonic noise measurements in the work environment.

In many countries, ultrasonic noise is included in the list of factors harmful to health in the work environment. For the frequency range above 20 kHz, there is no clear and complete information on the factors influencing the result of a measurement of sound pressure level. Moreover, there are no current international standards for performing measurements of ultrasonic noise at work stations. This article presents a possibility for the adaptation of the existing measurement methods [e.g., ISO 9612:2009 (2009)] to the ultrasonic range. In particular, it discusses the requirements for measuring instruments, procedures to be followed while performing measurements, the application of a correction to measurement results, and the determination of measurement uncertainty. The development of a consistent method of ultrasonic noise measurement is of utmost importance in carrying out an assessment and reducing the risk of exposure to this physical factor in the work environment.