Important Measurands Research Articles

Biological variation estimates obtained from Chinese subjects for 32 biochemical measurands in serum.

The European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) have established a program of work to make available, and to enable delivery of well characterized data describing the biological variation (BV) of clinically important measurands. Guided by the EFLM work the study presented here delivers BV estimates obtained from Chinese subjects for 32 measurands in serum. Samples were drawn from 48 healthy volunteers (26 males, 22 females; age range, 21-45years) for 5 consecutive weeks at Chinese laboratory. Sera were stored at-80°C before triplicate analysis of all samples on a Cobas 8000 modular analyzer series. Outlier and homogeneity analyses were performed, followed by CV-ANOVA, to determine BV estimates with confidence intervals. The within-subject biological variation (CVI) estimates for 30 of the 32 measurands studied, were lower than listed on the EFLM database; the exceptions were alanine aminotransferase (ALT), lipoprotein (a) (LP(a)). Most of the between-subject biological variation (CVG) estimates were lower than the EFLM database entries. This study delivers BV data for a Chinese population to supplement the EFLM BV database. Population differences may have an impact on applications of BV Data.

An Improved Magnetic Transduction Scheme and Electronic Processing for Sensing Rotary-Shaft Position Over Full-Circle Range

Angular position of a through-shaft is an important measurand whose value needs to be accurately estimated in a number of industrial scenarios. This paper brings forward the design, analysis and hardware-based evaluation of a new magnetic transduction module and associated electronics for through-shaft angle estimation. The proposed transduction module enables non-contact and full-circle operation using an intelligent arrangement of magnetic discs and two Hall sensors. This easy-to-fabricate module is analyzed and its (nonlinear) characteristics are derived. Optimal specifications for the transducer are also ascertained using this analysis. Further, a simple electronic processor, implementing new linearization function, is employed to realize an automated through-shaft sensing system. This system retains all merits of magnetic sensor and reluctance techniques and eliminated many issues of the previous through-shaft sensor systems. A hardware prototype of the transducer and electronic processor is built and tested. Test results show that the developed system can measure through-shaft angle over 360° range with error < 0.8%. The paper, in its final part, discusses the comparison of the developed scheme with prior art as well as the recommendations for fabricating an equivalent industrial model of the proposed system.

Within- and between-subject biological variation data for tumor markers based on the European Biological Variation Study.

Reliable biological variation (BV) data are required for the clinical use of tumor markers in the diagnosis and monitoring of treatment effects in cancer. The European Biological Variation Study (EuBIVAS) was established by the EFLM Biological Variation Working Group to deliver BV data for clinically important measurands. In this study, EuBIVAS-based BV estimates are provided for cancer antigen (CA) 125, CA 15-3, CA 19-9, carcinoembryonic antigen, cytokeratin-19 fragment, alpha-fetoprotein and human epididymis protein 4. Subjects from five European countries were enrolled in the study, and weekly samples were collected from 91 healthy individuals (53 females and 38 males; 21-69 years old) for 10 consecutive weeks. All samples were analyzed in duplicate within a single run. After excluding outliers and homogeneity analysis, the BVs of tumor markers were determined by CV-ANOVA on trend-corrected data, when relevant (Røraas method). Marked individuality was found for all tumor markers. CYFRA 21-1 was the measurand with the highest index of individuality (II) at 0.67, whereas CA 19-9 had the lowest II at 0.07. The CV I s of HE4, CYFRA 21-1, CA 19-9, CA 125 and CA 15-3 of pre- and postmenopausal females were significantly different from each other. This study provides updated BV estimates for several tumor markers, and the findings indicate that marked individuality is characteristic. The use of reference change values should be considered when monitoring treatment of patients by means of tumor markers.

Feeling Machine for Process Monitoring of Components with Stock Allowance

To realize the increasing automation and flexibilization of production, it is necessary to monitor component-specific characteristics under fluctuating production conditions. Signals with a high correlation to the process quality have to be evaluated. In machining, the process force is an important measurand, which is sensitive to changes in the process. Feeling machines with force-sensitive machine tool components are therefore a promising signal source to monitor the machining. However, the force is also sensitive to non-critical process fluctuations such as stock allowance. Consequently, it is necessary to perform signal pre-processing and generate features that increase the robustness of the monitoring. In this paper, the material-specific cutting force was investigated for the first time concerning its suitability for process monitoring of parts with a stock allowance. The sensitivity of confidence limits was evaluated based on the normed bandgap. For the investigation, face turning processes of 20MnCr5 were carried out. The results show that the use of material-specific cutting force improves the sensitivity of the confidence limits to process errors. In this context, the feeling machine can be used to substitute the dynamometer for process monitoring.

Microwave Measurements for Conductive Anisotropic Materials

Applications of anisotropic composite materials range from construction composites to electric circuit boards. Anisotropic conductivity is one of the many important measurands for anisotropic composites for identifying misalignment. However, there are only a few nondestructive, noncontact techniques available. Here, we explore waveguide ellipsometry, a new electromagnetic characterization technique, and its application to conductive anisotropic composites. We demonstrate waveguide ellipsometry and discuss the design and implementation of a novel rotation test head on a robotic arm. To validate our technique, we designed and fabricated test wafers with ideal anisotropic composites consisting of gold stripes on materials with varying sheet resistances. The measurements were compared to full-wave simulations with simulated material properties extracted with the help of composite theory and simple circuit analysis. We found a good match between the simulated and measured complex scattering (S-) parameters for all test wafers fabricated with molybdenum disilicide (MoSi2) and gold stripes. Finally, we map the measured S-parameters to simulated S-parameters with help from composite theory and circuit modeling. Broader impacts of microwave ellipsometry include in-line measurement and conductivity imaging of large-scale and 3-D parts for nondestructive evaluation.

European Biological Variation Study (EuBIVAS): within- and between-subject biological variation estimates for serum biointact parathyroid hormone based on weekly samplings from 91 healthy participants.

The European Biological Variation Study (EuBIVAS) was created by the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Working Group on Biological Variation to establish high-quality biological variation (BV) estimates for clinically important measurands. In this study, the aim was to deliver reliable BV estimates for the biointact parathyroid hormone (PTH 1-84). Serum samples were obtained from a population of 91 healthy individuals (38 men, 43 pre-menopausal women, and 10 post-menopausal women; 21-69 years) from 5 European countries, with all samples stored at -80 °C prior to analysis. PTH 1-84 analysis was performed at the San Raffaele Hospital (Milan, Italy) on the Roche Cobas e801. All samples from each individual were analysed in duplicate within a single run. CV-ANOVA was applied, after analysis of variance homogeneity and outliers, to obtain BV estimates for PTH 1-84 with 95% CIs. The within-subject BV [CVI (95% CI)] estimates were significantly different between men and women [13.0% (12.1-14.2%) and 15.2% (14.3-16.3%), respectively], while the between-subject estimates [CVG (95% CI)] were similar (men: 26.8% (21.4-35.1%), pre-menopausal women: 27.8% (22.7-36.1%)], allowing for delivery of updated analytical performance specifications and reference change values. Updated BV estimates for serum PTH 1-84 based on the large-scale EuBIVAS may be beneficial for the diagnosis and management of parathyroid glands and bone turnover pathologies.

Comparison of CRMs and value-assigned quality controls: urea and uric Acid in human serum or plasma (CCQM-K142)

The CCQM OAWG 2017 CCQM-K142 "Comparison of CRMs and Value-Assigned Quality Controls: Urea and Uric Acid in Human Serum or Plasma" is the third Model 2 Key Comparison coordinated by the OAWG directly testing the chemical measurement services provided to customers by National Metrology Institutes (NMIs) and Designated Institutes (DIs) through certified reference materials (CRMs). CRMs certified for urea and/or uric acid content in human serum or plasma were compared using measurements made on these materials under repeatability conditions. Four NMIs/DIs submitted 10 CRMs certified for urea; five NMIs/DIs submitted 12 CRMs certified for uric acid. These materials represent most of the higher-order reference materials available then for these clinically important measurands. Uncertainty-weighted generalised distance regression was used to establish the Key Comparison Reference Function (KCRF) relating the CRM certified values to the repeatability measurements. The urea results for all 10 CRMs were considered to be equivalent at the 95 % level of confidence and were used to define the KCRF for urea. The uric acid result for one of the 12 CRMs was found to be non-equivalent: the submitting NMI re-evaluated the result and withdrew the material from use in defining the KCRF for uric acid. The remaining 11 CRMs were used to define the KCRF for uric acid. Monte Carlo methods were used to estimate 95 % level-of-confidence coverage intervals for the relative degrees of equivalence of materials, %d ± U95 (%d), and of the participating NMIs/DIs, %D ± U95 (%D). For the urea materials, the %D ± U95(%D) intervals were within (-3 to 5) % of the consensus results. For the uric acid materials from four of the five NMIs/DIs, the %D ± U95(%D) intervals were within (-4 to 5) % of the consensus results. These results demonstrated that with the exception of one material, the participating institutions could value-assign CRMs for urea and/or uric acid in human serum and plasma.KEY WORDS FOR SEARCHCertified reference materials; urea; uric acid; human serum; key comparison reference functionMain textTo reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

The EuBIVAS: Within- and Between-Subject Biological Variation Data for Electrolytes, Lipids, Urea, Uric Acid, Total Protein, Total Bilirubin, Direct Bilirubin, and Glucose.

The European Federation of Clinical Chemistry and Laboratory Medicine European Biological Variation Study (EuBIVAS) has been established to deliver rigorously determined data describing biological variation (BV) of clinically important measurands. Here, EuBIVAS-based BV estimates of serum electrolytes, lipids, urea, uric acid, total protein, total bilirubin, direct bilirubin, and glucose, as well as their associated analytical performance specifications (APSs), are presented. Samples were drawn from 91 healthy individuals (38 male, 53 female; age range, 21-69 years) for 10 consecutive weeks at 6 European laboratories. Samples were stored at -80 °C before duplicate analysis of all samples on an ADVIA 2400 (Siemens Healthineers). Outlier and homogeneity analyses were performed, followed by CV-ANOVA on trend-corrected data, when relevant, to determine BV estimates with CIs. The within-subject BV (CVI) estimates of all measurands, except for urea and LDL cholesterol, were lower than estimates available in an online BV database, with differences being most pronounced for HDL cholesterol, glucose, and direct bilirubin. Significant differences in CVI for men and women/women <50 years of age were evident for uric acid, triglycerides, and urea. The CVA obtained for sodium and magnesium exceeded the EuBIVAS-based APS for imprecision. The EuBIVAS, which is fully compliant with the recently published Biological Variation Data Critical Appraisal Checklist, has produced well-characterized, high-quality BV estimates utilizing a stringent experimental protocol. These new reference data deliver revised and more exacting APS and reference change values for commonly used clinically important measurands, thus having direct relevance to diagnostics manufacturers, service providers, clinical users, and ultimately patients.

Data fusion based multi-rate Kalman filtering with unknown input for on-line estimation of dynamic displacements

Structural dynamic displacement is one of the most important measurands that describe the dynamic characteristics of a structure. However, accurate measurement of dynamic displacements of a civil infrastructure is still a challenging task. To solve the difficulties and drawbacks of direct dynamic displacement measurement, the approach of multi-rate Kalman filtering for the data fusion of displacement and acceleration measurement was developed. Recently, an improved technique for dynamic displacement estimation by fusing biased high-sampling rate acceleration and low-sampling rate displacement measurements has been proposed. However, this technique can only take constant acceleration bias into account. In this paper, based on the algorithm of Kalman filter with unknown input recently developed by the authors, dynamic displacement is on line estimated based on multi-rate data fusion of high-sampling rate acceleration with time-varying bias and low-sampling rate displacement measurements. The time history of time-varying acceleration bias is treated as “unknown input” in the algorithm of Kalman filter with unknown input to overcome the limitations of the previous technique. Some numerical examples with linear or polynomial acceleration bias are used to demonstrate the effectiveness of the proposed approach for on line estimation of structural dynamic displacement.

Evaluation of radiosonde humidity sensors at low temperature using ultralow-temperature humidity chamber

Abstract. Accurate measurements of temperature and water vapor in the upper-air are of great interest in relation to weather prediction and climate change. Those measurements are mostly conducted using radiosondes equipped with a variety of sensors that are flown by a balloon up to lower stratosphere. Reference Upper Air Network (GRUAN) has identified water vapor pressure as one of the most important measurands and has set an accuracy requirement of 2 % in terms of the mixing ratio. In order to achieve the requirement, many errors in the humidity measurement such as a temperature dependency in sensing characteristics including measurement values and response time need to be corrected because humidity sensors of radiosondes pass through low-pressure (1 kPa) and low-temperature (−80 ∘C) environments in the upper-air. In this paper, the humidity sensing characteristics of Jinyang radiosonde sensors in relation to temperature dependencies were evaluated at low temperature using a newly developed ultralow-temperature humidity chamber. The sensitivity characteristic curve of the radiosonde sensors was evaluated down to −80 ∘C, and the calibration curves of the humidity sensor and the temperature sensor were obtained. The response time of humidity sensor slowly increased from 52 to 116 s at the temperature from 20 to −40 ∘C, respectively, and then rapidly increased to almost one hour at −80 ∘C. Those results will help to improve the reliability of the upper-air observation data.

Cast Iron Components with Intelligence

The paper describes a project with the aim to develop communicating and functional cast iron components in smart systems. The concept is based on sensors integrated into cast iron components; this will influence not only the component but also the casting process. Among the technical challenges is how to choose a sensor solution that cost-efficiently and with minimal environmental impact can be integrated into the component during the casting process, and especially without being damaged during mold filling and the high pouring temperature. Another challenge is how the iron will interact and interfere with sensor signals and whether an insulating intermediate material is needed or not. Integrating the sensors into the casting makes sensors a natural part of the component, which in turn can lead to more resource efficient designs, increased value added for the casting sector, and a general access to different possibilities of digitalization. The integrated sensors can be used for effective control and monitoring of components when in service and give information about for example how the component is used and what conditions it is exposed to. In other words, the component can tell when maintenance is needed or in worst cases, indicate that something is wrong before a failure will happen. Important measurands can e.g. be elongation, shear, temperature and vibration. Different combinations of sensor materials and insulating materials and their interaction with the cast iron have been investigated. It is shown how the interaction at the interface affects the microstructure and consequently the properties of the cast iron. In the case of insulating materials it is e.g. shown how air gaps are formed and in the case of sensor materials it is shown how a diffusion zone is formed and how this zone depends on the sensor material. How this diffusion zone affects the microstructure is discussed.

Frequency-Division-Multiplex-Based Quantum Efficiency Determination of Solar Cells

Quantum efficiency (QE) is an important measurand that contains extensive information about the electrical and optical properties of photovoltaic devices. During device characterization, the measurement is, therefore, mandatory and necessary for, e.g., spectral mismatch correction of subsequent examinations. In this paper, a new real-time characterization method is presented, which allows accelerating QE measurements by a factor of more than 500 times without significantly degrading measurement accuracy, optical bandwidth, and resolution. The increased measurement speed is achieved by a frequency-division multiplexing approach using a spatial light modulating element, which allows it to illuminate the cell under test simultaneously with all wavelengths of interest. Feasibility and reproducibility are demonstrated in experimental measurements and validated by comparison with Fraunhofer ISE CalLab instruments.

A reference system for urinary albumin: current status

Increased urinary excretion of albumin reflects kidney damage and is a recognized risk factor for progression of renal and cardiovascular disease. Considerable inter-method differences have been reported for both albumin and creatinine measurement results, and therefore the albumin-to-creatinine ratio. Measurement accuracy is unknown and there are no independent reference measurement procedures for albumin and no reference materials for either measurand in urine. The National Kidney Disease Education Program (NKDEP) Laboratory Working Group and the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) have initiated joint projects to facilitate standardization of urinary albumin and creatinine measurement. A candidate LC-MS/MS reference measurement procedure for urinary albumin and candidate reference materials for urinary albumin and creatinine has been developed. The status of validations of these reference system components is reported. The development of certified reference materials and reference measurement procedures for urinary albumin will enable standardization of this important measurand.

Neural Network-Based Interface Level Measurement in Pipes Using Peripherally Distributed Set of Electrodes Sensed Symmetrically and Asymmetrically

Pipe separators are currently being assessed as substitutes for conventional separators in the oil and gas industry for the separation of gas, oil, and water. In the process of separation, the interface levels between the different media are important measurands to be monitored to optimize the separation process. Electrical capacitance tomography (ECT) without too much focus on tomograms can be used to detect the interfaces in a separator with enough accuracy for control purposes. With the easing of the CPU time needed for image processing, the possibility of getting enough information from reduced number of electrodes has also to be looked into, in view of reducing the processing time. The performance of the ECT system with reduced number of electrodes is studied in this paper using inferential methods based on artificial neural networks. Performance of a 12-electrode ECT system is assessed by studying its performance with only 6, 5, and 4 electrodes. The detection/estimation of interfaces is done effectively and in much shorter time compared to the processing of data with tomograms using a 12-electrode system. The inferential method can handle nonlinearity, and results from it can be easily integrated into other control algorithms addressing the actuators used in separators.

Wireless sensing using acoustic signals for measurement of dynamic pressure and temperature in harsh environment

Purpose – It is currently difficult to measure temperature and pressure in harsh environments. Such measurements are limited by either the ability of the sensing element or the associated electrical wiring to withstand the operating environment. This is unfortunate as temperature and pressure are important measurands in various engineering structures as they provide critical information on the operating condition of the structure. Hence, there is a need to address this shortcoming. Such a sensor in place would enhance the operating efficiency thereby reducing the pollution burden and its impact on the environment. The purpose of this paper is to present theoretical and preliminary experimental results for a co‐integrated pressure and temperature sensor for harsh environments.Design/methodology/approach – This work describes a co‐integrated pressure‐temperature wireless sensing scheme. The approach presented herein provides the possibility of measuring dynamic pressure and temperature within an enclosed vo...

ISFET technology for multi-sensor technology: from lab-in-a-pill to massively parallel measurements

Laboratory-in-a-pill, or capsule endoscopy, became a reality almost as soon as the invention of the transistor enabled miniaturisation of circuits into a small enough device. Of the many possible sensor modalities pH has emerged as an important measurand for diagnostics and laboratory analysis. Presented is the background to the early instances of the technology, including a summary of the published work on pill-based diagnostic devices. Then, how concepts from pill technology have led to further sensor integration, and to sensor system on chip (SSOC) in particular is presented. To conclude, consideration is given to how many ISFETs have been integrated using SSOC technology, and how this technology has led to the development of post-light gene sequencing systems using CMOS.

Quantitative analysis of physical and chemical measurands in honey by mid-infrared spectrometry

Fourier transform infrared spectroscopy (FT-IR) was used to determine 20 different measurands in honey. The reference values for 144 honey samples of different botanical origin were determined by classical physical and chemical methods. Partial least squares regression was used to develop the calibration models for the measurands studied. They were validated using independent samples and proved satisfying accuracies for the determination of water (R 2=0.99), glucose (0.94), fructose (0.84), sucrose (0.91), melezitose (0.98) and monosaccharide content (0.82) as well as fructose/glucose ratio (0.98), glucose/water ratio (0.94), electrical conductivity (0.98), pH-value (0.87) and free acidity (0.96). The prediction accuracy for hydroxymethylfurfural, proline and the minor sugars maltose, turanose, erlose, trehalose, isomaltose and kojibiose was rather poor. The results demonstrate that mid-infrared spectrometry is a valuable, rapid and non-destructive tool for the quantitative analysis of the most important measurands in honey.

Final report on CCL-S3 supplementary line scale comparison Nano3

This report describes the results of the international line scale comparison Nano3, which was carried out between 2000 and 2003 and which was accepted as supplementary comparison CCL-S3. This comparison was initiated by the BIPM working group on nanometrology as one of five international comparisons in the field of dimensional nanometrology. Two high quality line scales, one made of Zerodur and one made of fused silica (quartz), with 280 mm main graduation length and additional smaller graduations of only a few mm were chosen as transfer standards. These scales were produced using advanced and optimized lithography and processing technologies by the Dr Johannes Heidenhain GmbH, Germany. A considerable number of characterizations of the graduations were performed in order to ensure an optimized line edge quality of the scales used in the comparison. Moreover, it was decided to have long gauge blocks manufactured out of the same piece of substrate material as was used for the scales. In this way, it was possible to independently determine important substrate material parameters like thermal expansion, compressibility and to investigate the long-term stability of the substrate materials.The Zerodur line scale standard revealed a small length reduction of about (−7 ± 4)×10-8/a, which was confirmed by the measurements on the long gauge blocks. This length change of the Zerodur line scale could be taken into account for the comparison of participant's data by the application of a linear drift model. On the quartz samples and linescales no comparable effects were observed.The line scales were measured by 13 national metrology institutes from four different metrology regions. Two institutes decided to withdraw from Nano3 after the measurements were performed, but before Draft A was circulated. The measurement uncertainties that were evaluated by the participants over the 280 mm length of the graduations showed a variation from about 300 nm down to 30 nm.The good line edge quality of both scales allowed a meaningful separation of the length-dependent and length-independent deviations from the weighted mean values. Therefore a meaningful comparison of these deviations with the evaluated uncertainty contributions of the participating institutes was possible.For the most important measurand of this comparison, namely the position deviations of the line structures on the 280 mm main graduation, three results out of the 11 data sets provided had to be excluded by application of the En-criterion for the quartz and Zerodur scales respectively. Investigations of the reasons for the deviations have already been started by the respective institutes, including bilateral follow-up line scale comparisons with the Nano3 pilot laboratory.Main text.To reach the main text of this paper, click on Final Report.Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCL, according to theprovisions of the Mutual Recognition Arrangement (MRA).

The Tensiograph - A Novel Instrument for the Fingerprinting and Analysis of Multiple Physical Attributes of Beer

A brief description of the tensiograph multianalyser (formerly known as the fibre drop analyser) is given. The complex multi-measurand nature of the signal, known as the tensiotrace, is explained and a brief outline given of the methods for obtaining the most important measurands from these signals for the analysis of beer. An extensive background study has been made of the basic components of beverages using the multianalyser, which investigated the basic capabilities of the instrument for the analysis of sugars, alcohols and proteins. The most important results are summarised briefly because these define a background instrumental capability for the more complex problem of the analysis of beer. A range of commercially available alcoholic beverages has been studied with the multianalyser using matching analysis. This analysis is given in terms of match values (M-values) of the drop period, peak heights and times, point matches and area matches obtained from the comparison of experimental tensiotraces. In a study of seventeen commercial beverages it has been demonstrated that an LED multianalyser is able to fingerprint beers. Quantitative information on the physical and chemical properties of these products was also obtained. In this study it was found that two of the beers were so close in every respect of their physical properties that the LED multianalyser had difficulty in distinguishing one from the other. Results on two sets of blind tests of samples are described. The first on a set of alcohol spiked samples obtained from an industrial source and organised by Brewing Research International, Surrey was successful in obtaining measurements of the physical properties of these samples. The second blind test addressed the more difficult problem of fingerprinting various types and batches of the same product with the multianalyser. The results of these tests are presented and the difficulties experienced in conducting these measurements are explained. Finally, in the light of the work on fingerprinting, demonstration of the real capability of the multianalyser was attempted with a study of various mixtures of two beers. Difference value (D-value) analysis is used to determine the level of admixture of the two stout products employing a calibration procedure. The potential of the multianalyser technique in the area of beer analysis is reviewed.