Metrology

Several materials widely used in scientific research and industrial applications, including nano-filters and neuromorphic circuits, consist of fiber structures. Despite the fundamental structural similarity, the key feature that should be considered depends on the specific application. In the case of membranes and filters, the main concern has been on the pores among fibers, whereas in neuromorphic networks the main functionality is performed through the junctions of nanowires simulating neuron synapses for information dissemination. Precise metrological characterization of these structural features, along with methods for their effective control and replication, is essential for optimizing performance across various applications. This paper presents a comprehensive metrological framework for characterizing the spatial point patterns formed by pores or junctions within fibrous materials. The aim is to probe the influence of fiber randomness on both the point patterns of intersections (ppi) and pores (ppp). Our findings indicate a strong tendency of ppi toward aggregation, contrasting with a tendency of ppp toward periodicity and consequent pore uniformity. Both patterns are characterized by peculiarities related to collinearity effects on neighboring points that cannot be captured by the conventional anisotropy analysis of point patterns. To characterize local collinearity, we develop a method that counts the number of collinear triplets of nearest neighbor points in a pattern and designs an appropriate parameter to quantify them, also applied to scanning electron microscopy (SEM) images of membranes, demonstrating consistency with simulated data. Full article

Metrological traceability is essential for ensuring the accuracy of measurement results and enabling a comparison of results to support decision-making in society. This paper explores a structured approach to modelling traceability chains, focusing on the role of residual measurement errors and their impact on measurement accuracy. This work emphasises a scientific description of these errors as physical quantities. By adopting a simple modelling framework grounded in physical principles, the paper offers a formal way to account for the effects of errors through an entire traceability chain, from primary reference standards to end users. Real-world examples from microwave and optical metrology highlight the effectiveness of this rigorous modelling approach. Additionally, to further advance digital systems development in metrology, the paper advocates a formal semantic structure for modelling, based on principles of Model-Driven Architecture. This architectural approach will enhance the clarity of metrological practices and support ongoing efforts toward the digital transformation of international metrology infrastructure. Full article

Three-dimensional measurement technologies based on computer vision have been developed with the aim of achieving perceptual speeds equivalent to humans (30 fps). However, in a highly mechanized society, there is no need for computers and robots to work slowly to match the speed of human perception. From this kind of circumstance, high-speed 3D vision with speeds far beyond that of humans, such as 1000 fps, has emerged. High-speed 3D measurement has great applicability not only for accurately recognizing a moving and deforming target but also for enabling real-time feedback, such as manipulation of the dynamic targets based on the measurement. In order to accelerate 3D vision and control the dynamic targets in real time, high-speed vision devices and high-speed image processing algorithms are essential. In this review, we revisit the basic strategy, triangulation as a suitable measurement principle for high-speed 3D vision, and introduce state-of-the-art 3D measurement methods based on high-speed vision devices and high-speed image processing utilizing structured light patterns. In addition, we introduce recent applications using high-speed 3D measurement and show that high-speed 3D measurement is one of the key technologies for real-time feedback in various fields such as robotics, mobility, security, interface, and XR. Full article

Blood concentrations of essential trace elements can be used to diagnose conditions and diseases associated with excess or deficiency of these elements. Inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and graphite furnace atomic absorption spectrometry (GF-AAS) have been employed for such measurements, but maintenance and operation costs are high. X-ray fluorescence (XRF) detectability in cutaneous blood of iron (Fe), copper (Cu), zinc (Zn), and selenium (Se) was assessed as an alternative to ICP-MS. Three phantoms were made up of two polyoxymethylene (POM) plastic cylindrical cups of 0.6 mm and 1.0 mm thick walls and a 5.3 mm diameter POM cylindrical insert. Six aqueous solutions of Fe in 0 to 500 mg/L and Cu, Zn, and Se in 0 to 50 mg/L concentrations were poured into the phantoms to simulate X-ray attenuation of skin. Measurements using an integrated X-ray tube and polycapillary X-ray lens unit generated 24 calibration lines. Detection limit intervals in mg/L were (36–100), (14–40), (3.7–10), and (2.1–3.4) for Fe, Cu, Zn, and Se, respectively. Fe was the only element with detection limits lower than its 480 mg/L median human blood concentration. The estimated radiation dose and equivalent dose to skin were below those of common radiological procedures. Applications will require further instrumental development and finding a calibration method. Full article

The High-Intensity Heavy-Ion Accelerator Facility (HIAF) is a significant national science and technology infrastructure project, constructed by the Institute of Modern Physics, Chinese Academy of Sciences (IMP, CAS). It is designed to provide intense proton, heavy ion beams, and target-produced radioactive ion beams for nuclear physics and related research. Large-aperture, high-precision, room-temperature, and superconducting dipole magnets are extensively used to achieve high-intensity beams. However, for large-scale magnets (particularly superconducting magnets), the traditional Hall probe mapping measurement platform encounters several limitations: a long preparation time, high cost, low testing efficiency, and positional inaccuracies caused by repeated magnet disassembly. This paper presents a new magnetic field mapping measurement system incorporating ultrasonic motors operable in strong magnetic fields (≥7 T), enabling portable, highly efficient, and high-precision magnetic field measurements. After system integration and commissioning, the prototype dipole magnet for the high-precision spectrometer ring (SRing) was measured. The measurement system demonstrated superior accuracy and efficiency compared with traditional Hall probe mapping systems. On this basis, the magnetic field distribution and integral excitation curve of all 11 warm-iron superconducting dipole magnets and 3 anti-irradiation dipole magnets in the HIAF fragment separator (HFRS) were measured. Each magnet took less than 1 day to measure, and all magnetic field measurement results met the physical specifications. Full article

GaN High-Electron-Mobility Transistors have gained some foothold in the power-electronics industry. This is due to wide frequency bandwidth and power handling. Gallium Nitride offers a wide bandgap and higher critical field strength compared to most wide-bandgap semiconductors, resulting in better radiation resistance. Theoretically, it supports higher speeds as the device dimensions could be reduced without suffering voltage breakdown. The simulation and experimental results illustrate the superior performance of the Gallium Nitride High-Electron-Mobility Transistors in an amplifying circuit. Using a spice model for commercially available Gallium Nitride High-Electron-Mobility Transistors, non-distorted output to an input signal of 200 ps was displayed. Real-world measurements underscore the fast response of the Gallium Nitride High-Electron-Mobility Transistors with its measured slew rate at approximately 3000 V/μs, a result only 17% lower than the result obtained from the simulation. This fast response, coupled with the amplifier radiation resistance, shows promise for designing improved detection and imaging circuits with long Mean Time Between Failure required, for example, by next-generation industrial-process gamma transmission-computed tomography. Full article

Non-collaborative (i.e., reflective, transparent, metallic, etc.) surfaces are common in industrial production processes, where 3D reconstruction methods are applied for quantitative quality control inspections. Although the use or combination of photogrammetry and photometric stereo performs well for well-textured or partially textured objects, it usually produces unsatisfactory 3D reconstruction results on non-collaborative surfaces. To improve 3D inspection performances, this paper investigates emerging learning-based surface reconstruction methods, such as Neural Radiance Fields (NeRF), Multi-View Stereo (MVS), Monocular Depth Estimation (MDE), Gaussian Splatting (GS) and image-to-3D generative AI as potential alternatives for industrial inspections. A comprehensive evaluation dataset with several common industrial objects was used to assess methods and gain deeper insights into the applicability of the examined approaches for inspections in industrial scenarios. In the experimental evaluation, geometric comparisons were carried out between the reference data and learning-based reconstructions. The results indicate that no method can outperform all the others across all evaluations. Full article

Quantitative determination of the uncertainty of a measurement result is the key to assessing the quality and reliability of a measurement process and its result. The comparability of measurement results is ensured by the method for evaluating and expressing uncertainty defined by the Joint Committee for Guides in Metrology, where the model of the measurement process—which expresses the causal relationship of the measurand and the input quantities—is fundamental for the uncertainty evaluation. Setting up this model is very specific to the particular measurement setup and process, as well as the required level of detail. In this contribution, a vectorial method is presented which has been developed to assist users in modelling complex relationships, based on basic physical effects and their combination. Using a hierarchical approach, the method aims to be flexible, extensible and adaptable to a wide range of applications. Full article

Medical laboratories are perhaps the largest measurement industry in the world. The metrology terminology is relevant for effective and efficient communication, particularly where metrology activities are carried out by operators with different metrology skills. The World Association of Societies of Pathology and Laboratory Medicine (WASPaLM) and SIPMeL have had some opportunities to propose changes to the documents in preparation for the Clinical and Laboratory Standards Institute (CLSI) and the ISO/TC 212 in order to harmonize the terminology with the Metrology Vocabulary (VIM) of the Joint Committee for Guides in Metrology (JCGM). Many proposals have been accepted. Here, we summarize some particularly critical points for metrological terms. The main terms discussed are the following: measuring, measuring range, examination, pre-examination, post-examination, manufacturer, measuring instrument, quantitative, qualitative, semi-quantitative, processing, measurement error, maximum permissible error of measurement, total error of measurement, monitoring, variability, performance, reliability, influence, interference, selectivity, sensitivity, detection limit, reliability, comparability, compatibility, control material. Despite all the efforts to coordinate terminologies, it is inevitable that overlapping and inconsistent terminologies will continue to be used because documents and policies are produced in different contexts. In some ISO/TC 212 and CLSI documents, the phenomenon of magnetic attraction toward common words (such as “analysis” and derivatives), without any consideration of the true metrological meaning, is noted. The ISO/TC 212 and CLSI working groups show, alongside moments of openness, phenomena of true self-referential conservatism. Full article

The testing of rolling stock for the assessment of disturbance in signalling circuits is considered with a focus on the measurement process and the selection of operating conditions. The definition of interference limits is briefly reviewed, but they are considered an external input. The spectral behavior of acquired signals and the evaluation of repeatability are instead discussed with the help of three different real test cases, considering correspondence between similar operating points and differences as rolling stock operation evolves during a test run. Repeatability evaluated as standard deviation is in the order of 3% to 5% in the harmonic and audio frequency range for the different systems, slightly lower for AC railways; above about 10–15 kHz it increases to 30%. Uncorrelated components (with much lower amplitudes) may show much higher dispersion. Full article

Assessing the binder performance of thermal characterization is critical for quality control. This is pertinent for recovered binders from mixtures, which may not be in adequate quantities to evaluate their performance, particularly in mixtures containing reclaimed asphalt pavement (RAP). The present study deployed a thermogravimetric analyzer to evaluate compositional changes in recovered binders from RAP-containing mixtures, focusing on thermograph and derivative of thermograph (DTG) characteristics and correlating the results to rheological features. Incorporating RAP in mixtures influenced recovered binders’ DTG shapes, reducing low-combusted components (%LCC) and increasing residues (%R). The recovered binder from the zero-RAP-containing mixture showed a 4.36% increase in %LCC and a 1.97% decrease in %R compared to the short-term aged original binder. Binders recovered from RAP-containing mixtures exhibited greater stiffness than the short-term aged original binders. The %LCC dropped from 7.22% to 25.52%, while the %R increased from 20.69% to 33.06%. Uncertainty analyses showed that the DTG area and %R had the least uncertainty and that the %LCC had greater uncertainty. Analysis through regression revealed that DTG area and %R can predict G*/sinδ well, showing a correlation between better thermal stability and binder stiffness. This research puts a number on the correlation between thermal and rheological properties, which helps to improve quality control for binders. Full article

We present the design, construction, measurement, and troubleshooting of a prototype hybrid Halbach quadrupole magnet. This magnet was significantly under-strength due to local demagnetization in the permanent magnet material. We discuss how this effect was uncovered, how it was verified by performing Hall probe measurements of the individual magnet blocks, and how the effect was reconstructed in simulations. Full article

This paper introduces a method for calibrating radar sensors in a multi-sensor cinemometer system using a reference cinemometer based on CW Doppler radar. The method involves synchronizing sensors, pairing data with reference measurements, and performing polynomial corrections. Tests conducted on various traffic sites demonstrate the accuracy and reliability of the calibration process. Results show low uncertainties compared to regulatory standards. Validation against a calibrated lidar system confirms accuracy. This method ensures precise speed measurements, surpassing regulatory requirements, and demonstrating practical applicability in real-world scenarios. Full article

The capability of low-cost photogrammetric systems to provide live six degrees of freedom (6DoF) tracking of multiple objects offers great value in providing high-quality and consistent part production by automated manufacturing systems. However, monitoring of high-speed components, such as cutting heads, presents several unique challenges that existing systems struggle to meet. The solution given here uses a small number of short-exposure imaging sensors coupled with high-intensity lighting and retrorefective markers to allow for high-speed capture. The use of an initial characterization process carried out using IDEKO’s VSET© system is followed by live object tracking in bespoke image processing software running on a consumer-grade computer. Once this system is in use, it can simultaneously capture images of multiple markers in less than 0.1 milliseconds and use these to determine the 6DoF of the objects that the markers define. 6DoF recalculation of all objects within each measurement instance makes the system resilient to large movements, object occlusion, and sensor relocation. Feasibility tests of a four-camera system as a machine characterization tool tracking a cutting tool spinning at up to 3000 rpm across a volume of 1 m³ achieved a mean reference marker agreement between tool poses of 2.5 µm with markers moving at up to 17.5 ms⁻¹. Given good photogrammetric geometry, 6DoF parameters of the spinning tool were determined to standard deviations of 37.7 µm and 0.086°. Full article

The development and study of Smart Grid technologies rely heavily on high-fidelity data from Phasor Measurement Units (PMUs). However, the scarcity of real-world PMU data due to privacy, security, and variability issues poses significant challenges to researchers, developers, and related industries. To address these challenges, this article introduces the bases for a digital metrology framework, focusing on a newly designed and developed synthetic PMU data generator, that is both metrologically accurate and easy to adapt to various grid configurations for data generation from point-on-wave (PoW) data. This initial phase for a Smart Grid research framework aligns with Open Science principles, ensuring that the generated data are Findable, Accessible, Interoperable, and Reusable (FAIR). By embracing these principles, the generated synthetic data not only facilitate collaboration for Smart Grid research but also ensure their easy integration into existing Smart Grid simulation environments. Additionally, the proposed digital metrology framework for Smart Grid research will provide a robust platform for simulating real-world scenarios, such as grid stability, fault detection, and optimization. Through this open science approach, future digital metrology frameworks can support the acceleration of research and development, overcoming current limitations, e.g., lack of significant amounts of real-world scenarios by PMU data. This article also presents an initial case study for situational awareness and control systems, demonstrating the potential for future Smart Grid research framework and its direct real-world impact. All research outcomes are provided to highlight future opportunities for reusability and collaborations by a novel approach for research on sensor network metrology. Full article

Ultrasonic flow meters (UFMs) by transit time are ubiquitous in industrial applications, mainly for their versatility and practicality. They are widely used in gas and liquid installations, such as the oil and gas industry or feedwater systems in nuclear power plants. Computational fluid dynamics (CFD) techniques can be used as a tool to potentially improve the ultrasonic flow measurements. CFD may contribute to predicting the velocity profile and the profile factor in disturbed flows, integrating fluid flow and acoustic ray, improving the calibration of UFMs, or assisting in design optimization. This communication presents the working principle of the UFM, discusses how CFD can be used as a tool to support improvements, and shows relevant trending fields that deserve further investigation to promote significance on this subject. Full article

Environmental monitoring and remediation of hydrocarbon contamination in soil, particularly through passive methods, has become a critical area of focus for oil companies adapting to current environmental standards. Natural source zone depletion (NSZD) is a passive remediation process in which the degradation of petroleum hydrocarbons by microorganisms produces measurable thermal effects on the subsurface. Accurate estimation of the NSZD rate is heavily dependent on the precision of temperature measurements, as small uncertainties in temperature can cause significant variations in the estimated rates. Despite growing interest in using subsurface temperature data for NSZD monitoring, there is a lack of studies addressing the impact of temperature measurement uncertainty on the reliability of depletion rate estimates. This paper proposes a Monte Carlo method approach to assess the propagation of temperature measurement uncertainties through the NSZD rate estimation process. By simulating different uncertainty scenarios, this work defines acceptable limits for temperature measurement errors to ensure accurate and representative NSZD rate calculations. For the analyzed case study, it was determined that the relationship between uncertainties was nearly linear, with a slope of 52.5 L m⁻² year⁻¹ in the estimated NSZD rate for each degree Celsius of uncertainty in the temperature measurements. Full article

Advances in silicon carbide fabrication techniques enable the fabrication of high aspect ratio non-line-of-sight structures. The further development of non-line-of-sight fabrication tools and the use of the non-line-of-sight structures requires a set of measurement techniques. The goals of the measurement techniques are to (1) quickly detect the success of the fabrication and determine when a failure occurs, (2) accurately measure the shape of the subsurface structure, and (3) accurately characterize the structure. The first goal is attained using subsurface optical microscopy and single point confocal microscopy with a demonstrated resolution of 3 μm. The second goal is attained using X-ray computer tomography with a resolution of 500 nm. The third goal requires the accuracy of scanning electron microscopy. The substructures are brought to the surface through focused ion beam milling if the structures are less than 30 μm deep and through ablation cleaving and polishing for deeper substructures. Full article

Waveform generation as part of on-chip built-in self-test (BIST) circuitry often necessitates sufficient linearity without expensive hardware overhead. Achieving high linearity is critical for accurate signal generation, especially in applications requiring high precision, such as biomedical and instrumentation applications. Currently, achieving the high linearity and precision required in signal generators often relies on costly hardware such as automated test equipment (ATE). This paper presents a DAC-based arbitrary waveform generator (AWG). We use a low-cost DAC and a fully digital on-chip testing and calibration approach to nullify the effect of the DAC’s non-linearity on the generated waveform. The ultra-low cost and high linearity benefit of the proposed waveform generator makes it highly suitable for integration into resource-constrained systems. The proposed approach is validated using simulation results of the small-area DAC designed in TSMC 0.18 μm technology and the testing and calibration algorithms implemented in MATLAB. The DAC, designed with a matching accuracy at only the 5-bit level, is able to generate a signal with an ENOB of 12 bits alongside an SFDR and THD surpassing 100 dB. This high level of signal purity is consistently maintained across 100 Monte Carlo simulations, demonstrating the robustness of the architecture against PVT variations as well as random mismatches. Full article