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The gravimetric isotope mixture method is the primary method to determine absolute isotope ratios. This method, however, depends on the existence of suitable spike materials and knowledge of their purities. Determining the purity of the spikes can be tedious and labour-intensive. In this publication, an advancement of the gravimetric isotope mixture method, rendering the determination of the purity of the spike materials unnecessary, is presented. The advancement combines mass spectrometry and ion chromatography leading to an approach being independent of the purity of the spike materials. In the manuscript the mathematical background and the basic idea of the novel approach are described using a two-isotope system like copper or lithium. [ABSTRACT FROM AUTHOR]

The inherent association between real quantum systems and their surrounding environment invariably results in decoherence, leading to the loss of entanglement. This diminution in entanglement coincides with a decline in the fidelity of transmitted information using the entangled quantum resource. This study scrutinizes the impact of the squeezed generalized amplitude damping (SGAD) channel on quantum Fisher information (QFI) parameters. The SGAD channel model, a versatile framework, is also employed to simulate other dissipative channels, including amplitude damping (AD) and generalized amplitude damping (GAD). Kraus operators facilitate the modeling of noisy channels. The results reveal that, within the SGAD channel, the QFI remains impervious to the squeezing variables (r and Φ ). In the GAD channel, F θ GAD undergoes enhancement to a constant value with an upswing in temperature (T), while the ϕ parameter in the GAD channel, F ϕ GAD , akin to the SGAD channel, surges around T = 2 before complete loss ensues. Concerning the AD channel, the θ component of the QFI initially experiences decoherence with an augmentation in the AD noise parameter (λ ). Subsequently, it is restored to its initial value with a further escalation in λ . Conversely, the ϕ component of the QFI in the AD channel experiences decoherence with an elevation in the AD noise parameter (λ ). [ABSTRACT FROM AUTHOR]

How well can multiple incompatible observables be implemented by a single measurement? This is a fundamental problem in quantum mechanics with wide implications for the performance optimization of numerous tasks in quantum information science. While existing studies have been mostly focusing on the approximation of two observables with a single measurement, in practice multiple observables are often encountered, for which the errors of the approximations are little understood. Here we provide a framework to study the implementation of an arbitrary finite number of observables with a single measurement. Our methodology yields novel analytical bounds on the errors of these implementations, significantly advancing our understanding of this fundamental problem. Additionally, we introduce a more stringent bound utilizing semi-definite programming that, in the context of two observables, generates an analytical bound tighter than previously known bounds. The derived bounds have direct applications in assessing the trade-off between the precision of estimating multiple parameters in quantum metrology, an area with crucial theoretical and practical implications. To validate the validity of our findings, we conducted experimental verification using a superconducting quantum processor. This experimental validation not only confirms the theoretical results but also effectively bridges the gap between the derived bounds and empirical data obtained from real-world experiments. Our work paves the way for optimizing various tasks in quantum information science that involve multiple noncommutative observables. [ABSTRACT FROM AUTHOR]

The importance and non-trivial properties of superconductor normal metal interfaces were discovered by Alexander Fyodorovich Andreev more than 60 years ago. Only much later, these hybrids have found wide interest in applications such as thermometry and refrigeration, electrical metrology, and quantum circuit engineering. Here we discuss the central properties of such interfaces and describe some of the most prominent and recent applications of them. [ABSTRACT FROM AUTHOR]

The generation of laser pulses with controlled optical waveforms, and their measurement, lie at the heart of both time-domain and frequency-domain precision metrology. Here, we obtain mid-infrared waves via intra-pulse difference-frequency generation (IPDFG) driven by 16-femtosecond near-infrared pulses, and characterise the jitter of sub-cycle fractions of these waves relative to the gate pulses using electro-optic sampling (EOS). We demonstrate sub-attosecond temporal jitter at individual zero-crossings and sub-0.1%-level relative amplitude fluctuations in the 10-kHz–0.625-MHz band. Chirping the nearly-octave-spanning mid-infrared pulses uncovers wavelength-dependent attosecond-scale waveform jitter. Our study validates EOS as a broadband (both in the radio-frequency and the optical domains), highly sensitive measurement technique for the jitter dynamics of optical waveforms. This sensitivity reveals outstanding stability of the waveforms obtained via IPDFG and EOS, directly benefiting precision measurements including linear and nonlinear (infrared) field-resolved spectroscopy. Furthermore, these results form the basis toward EOS-based active waveform stabilisation and sub-attosecond multi-oscillator synchronisation/delay tracking. [ABSTRACT FROM AUTHOR]

A method is described to measure the thermal expansion coefficient of fused quartz glass. The measurement principle is to monitor the change in resonance frequency of a Fabry–Perot cavity as its temperature changes; the Fabry–Perot cavity is made from fused quartz glass. The standard uncertainty in the measurement was less than 0.6 (nm · m - 1) · K - 1 , or 0.15 %. The limit on performance is arguably uncertainty in the reflection phase-shift temperature dependence, because neither thermooptic nor thermal expansion coefficients of thin-film coatings are reliably known. However, several other uncertainty contributors are at the same level of magnitude, and so any improvement in performance would entail significant effort. Furthermore, measurements of three different samples revealed that material inhomogeneity leads to differences in the effective thermal expansion coefficient of fused quartz; inhomogeneity in thermal expansion among samples is 24 times larger than the measurement uncertainty in a single sample. [ABSTRACT FROM AUTHOR]

Background: Stereo-DIC is a widely used optical measurement technique that provides a dense full-field 3D measurement of the shape, displacement, and strain of a solid sample. When compared with 2D-DIC, Stereo-DIC provides greater flexibility and expands its use beyond flat, planar specimens. Furthermore, the widespread availability of commercial systems has led to the adoption of the technique throughout industry, academia, and government research labs. Objective: Even though some research has been done to understand the effects of different experimental and stereo-DIC parameters, no reference is available to benchmark and compare the performance of current stereo-DIC algorithms to each other. Methods: This paper provides the description and analysis of a carefully controlled 3D experiment and associated images used to compare the results from five subset based DIC software packages. Both the images and analysis codes used in this paper to compare the results are described here and are available for download and use for continued research. Results: We show that over a very large range of motion, the 3D errors are very small, less than 80 μ m over a travel of ±20 mm out-of-plane and ±20 mm in-plane. While all codes performed similarly, there are important differences noted in the paper. Conclusion: The image sets and results comparison software are hosted by the International DIC Society (www.iDICs.org) and are freely available for download and analysis for comparison with results in this paper. Furthermore, it is hoped that this set of images can be used for future research in improving stereo-DIC by future authors. [ABSTRACT FROM AUTHOR]

The pendant drop tensiometry is a preferred primary method for measuring interfacial tension (IFT) or surface tension. In a typical experimental setup, Gravitational pull opposes an interfacial tension forces to cause a liquid drop to develop into a pendant-like shape. The process comprises quantitatively modifying a theoretical profile generated through calculating the Young–Laplace capillarity formula to such an experimental pendant drop analysis and information by performing digital image analysis. However, specific parameters of this method lead to uncertainty in the obtained value of IFT. The present work aims to determine the role of factors such as evaporation of the hanging drop and its changing volume in interfacial tension, which is acting as major source of error in determining IFT of distilled water. This study details the measurement process and evaluation of standard errors with interfacial tension readings of distilled water by using pendant drop method with three calibrated needles of diameters, 0.9 mm (20 G), 1.27 mm (18 G) and 1.65 (16 G) mm. The needle's diameter influenced the evaporation rate and the value of IFT. Also, it is essential to consider these factors for further evaluating measurement uncertainties when determining the IFT of biological fluids. In addition, the present study makes an effort to determine the measurement error associated with drop volume and evaporation rate of drop in study. The distilled water used in the measurement had an absolute Interfacial tension of 72 mN/m, and the enlarged measurement errors were predicted to be in the range of 0.4–0.6%. It is critical to consider these associated measurement errors when determining the IFT of liquids for metrological application such as establishing primary standards for measurement pertaining to biological fluids. [ABSTRACT FROM AUTHOR]

A new Forward Ray Tracing Instrument (FRTI) for simulating X-ray CT scanners is presented. The FRTI enables the modelling of various detector geometries to optimise instrument designs. The FRTI is demonstrated by comparing experimentally measured sphere centre-to-centre distances from two material measures with digital clones. The measured length deviations were smaller than the reconstructed grid spacing for both the experimental and simulated acquisitions. As expected the experimentally measured length deviations were larger than the simulated measurements. The results demonstrate the FRII's capability of simulating an X-ray CT scanner and performing length measurements. [ABSTRACT FROM AUTHOR]

Quantum metrology promises unprecedented precision of parameter estimation, but it is often vulnerable to noise. While significant efforts have been devoted to improving the metrology performance in Markovian environments, practical control schemes specifically designed for non-Markovian noises are much less investigated. Here, we propose two control-enhanced quantum metrology schemes that are suitable for tackling general non-Markovian noises described by noise channels or noise spectra. We conduct experiments to verify the efficacy of these schemes on a nuclear magnetic resonance system. The experimental results involving multiqubit probes show that the parameter estimation precision can be greatly improved, significantly surpassing the standard quantum limit, with our schemes. At present, non-Markovian noises are widely encountered on diverse quantum devices, the proposed schemes are relevant for realistic metrology applications on these platforms. Quantum metrology, a powerful paradigm for surpassing classical measurement precision, has been extensively studied for Markovian noise, while most practical physical processes obey non-Markovian dynamics. In this paper, the authors propose control-enhanced quantum metrology schemes to counteract non-Markovian noise and experimentally verify their efficacy. [ABSTRACT FROM AUTHOR]

Single-isotherm n(p, T90) results are reported for the gases Ar, N2, H2O, and D2O at vacuum wavelength λ = 1542.383 (1) nm. The argon and nitrogen isotherms were measured near 303 K; the water isotherms were measured near 373 K. Combined with the two previous articles of this series, the present results beget several insights via dispersion analyses. The argon result is highly consistent with static measurement plus ab initio calculation of dispersion polarizability. The nitrogen result is nominally consistent with one recent experiment and the dipole oscillator strength distributions, but the present work offers a refined estimate of the molar refractivity at optical wavelengths. For ordinary and heavy water, the dispersion trend is nominally consistent with existing liquid measurements. However, water's absorption features in the near-infrared preclude a reliable comparison of the present result with literature. [ABSTRACT FROM AUTHOR]

Psychometrics is historically grounded in the study of individual differences. Consequently, common metrics such as quantitative validity and reliability require between-person variance in a psychological variable to be meaningful. Experimental psychology, in contrast, deals with variance between treatments, and experiments often strive to minimise within-group person variance. In this article, I ask whether and how psychometric evaluation can be performed in experimental psychology. A commonly used strategy is to harness between-person variance in the treatment effect. Using simulated data, I show that this approach can be misleading when between-person variance is low, and in the face of methods variance. I argue that this situation is common in experimental psychology, because low between-person variance is desirable, and because methods variance is no more problematic in experimental settings than any other source of between-person variance. By relating validity and reliability with the corresponding concepts in measurement science outside psychology, I show how experiment-based calibration can serve to compare the psychometric quality of different measurement methods in experimental psychology. [ABSTRACT FROM AUTHOR]

With the continued shrinking of the critical dimensions (CDs) of wafer patterning, the requirements for modeling precision in optical proximity correction (OPC) increase accordingly. This requirement extends beyond CD controlling accuracy to include pattern alignment accuracy because misalignment can lead to considerable overlay and metal-via coverage issues at advanced nodes, affecting process window and yield. This paper proposes an efficient OPC modeling approach that prioritizes pattern-shift-related elements to tackle the issue accurately. Our method integrates careful measurement selection, the implementation of pattern-shift-aware structures in design, and the manipulation of the cost function during model tuning to establish a robust model. Confirmatory experiments are performed on a via layer fabricated using a negative tone development. Results demonstrate that pattern shifts can be constrained within a range of ±1 nm, remarkably better than the original range of ±3 nm. Furthermore, simulations reveal notable differences between post OPC and original masks when considering pattern shifts at locations sensitive to this phenomenon. Experimental validation confirms the accuracy of the proposed modeling approach, and a firm consistency is observed between the simulation results and experimental data obtained from actual design structures. [ABSTRACT FROM AUTHOR]

Angular-dependent magneto-optical Kerr effect (MOKE) and coplanar waveguide ferromagnetic resonance (CPW-FMR) measurements were performed to unravel the nature of anisotropy present in Ni 80 Fe 20 (Py) thin film. The "in-plane" angular variation of coercive field ( H c IP ) and resonance field ( H r IP ) confirms the magnetic anisotropy is negligible, where the spins are confined to the plane of the Py film. The variation of resonance field in "out-of-plane" geometry, H r OP , strongly indicates the presence of "out-of-plane" uniaxial anisotropy in the Py thin film. Also, the inverse spin Hall effect (ISHE) technique is employed to measure spin pumping-induced DC voltage, V ISHE , generated across the Py/Pt bilayer. The line shape analysis method has been utilized to distinguish ISHE and spin rectification contributions. The measured V ISHE at low (4 GHz) and high (35 GHz) frequencies confirm the pure spin current injected through the Py-Pt interface due to spin pumping using CPW-FMR setup, which has a direct bearing on the realization of quantum metrology through the spin current quantity. [ABSTRACT FROM AUTHOR]

Metrology is the science of measurement and its applications, whereas biometrology is the science of biological measurement and its applications. Biometrology aims to achieve accuracy and consistency of biological measurements by focusing on the development of metrological traceability, biological reference measurement procedures, and reference materials. Irreproducibility of biological and multi-omics research results from different laboratories, platforms, and analysis methods is hampering the translation of research into clinical uses and can often be attributed to the lack of biologists' attention to the general principles of metrology. In this paper, the progresses of biometrology including metrology on nucleic acid, protein, and cell measurements and its impacts on the improvement of reliability and comparability in biological research are reviewed. Challenges in obtaining more reliable biological and multi-omics measurements due to the lack of primary reference measurement procedures and new standards for biological reference materials faced by biometrology are discussed. In the future, in addition to establishing reliable reference measurement procedures, developing reference materials from single or multiple parameters to multi-omics scale should be emphasized. Thinking in way of biometrology is warranted for facilitating the translation of high-throughput omics research into clinical practices. [ABSTRACT FROM AUTHOR]

We demonstrate that the contextuality of measurement selection can enhance the precision of quantum metrology with a simple linear optical experiment. Contextuality is a nonclassical property known as a resource for various quantum information processing tasks. Recent studies show that contextuality by anomalous weak values can be utilized to enhance metrological precision, unraveling the role of contextuality in quantum metrology. Our contextual quantum metrology (coQM) scheme can elevate the precision of the optical polarimetry as much as 6 times the precision limit given by the Quantum Fisher Information. We achieve the contextuality-enabled enhancement with two mutually complementary measurements, whereas, in the conventional method, some optimal measurements to achieve the precision limit are either theoretically challenging to find or experimentally infeasible to realize. These results highlight that the contextuality of measurement selection is applicable in practice for quantum metrology. [ABSTRACT FROM AUTHOR]

This paper presents a metrology tool path planning algorithm using an iterative learning-extremum seeking control (ILESC) scheme that combines iterative learning control (ILC) and extremum seeking control (ESC) schemes. In many surface metrology systems, it is inevitable to avoid cosine error that introduces extra uncertainty to the measurement. Cosine error results from the angular misalignment between the measurement probe and the target surface. The proposed ILESC scheme is suitable to address this problem because, unlike the classical control method where the system tracks a given reference signal, ILESC simultaneously compensates for cosine error by simultaneously regenerating the metrology tool path while scanning the target surface, even in case of initial profile unknown. Since no initial geometry profile is given, ESC is deployed to adaptively track the shortest measured distance to the target, which approximately aligns the measurement probe in the perpendicular path to the target. Then, ILC is deployed to each set of measurements to ensure the algorithm converges to an acceptable error threshold given the system's uncertainty. The proposed scheme was implemented to measure the surface profile of a reference cylinder (ϕ25.4 mm) and freeform lens mold, and the effectiveness of ILESC was evaluated by comparing the measurement results and reference data. As a result, the implemented ILESC scheme showed a 0.32% deviation at full scale. [ABSTRACT FROM AUTHOR]

To address the measurement accuracy challenges posed by the internal flow complexity in atypical circular bend pipes with short turning sections and without extended straight pipe segments, this study designed an experimental circular "S"-shaped bent pipe with a diameter of 0.4 m and a bending angle of 135°. Numerical analysis was used to determine the stable region for velocity distribution within the experimental segment. Furthermore, a novel evaluation method based on the coefficient of variation was proposed to accurately locate the optimal position for installing thermal mass flow meters on the test cross section. Additionally, a formula for calculating the pipeline flow rate based on velocity differences was derived. This formula considers pipeline flow as the dependent variable and uses the velocity at two points in the test cross section as the independent variable. Experimental validation on a primary standard test bench demonstrated that the flow rate calculated by this method had an error controlled within 0.625% compared to the standard flow rate, thus effectively verifying the method's high accuracy and engineering applicability. This research provides a new testing methodology and practical basis for flow measurement in complex pipeline systems, offering significant guidance for research and applications in related fields. [ABSTRACT FROM AUTHOR]

A suite of measurements of refractive index n (p , T 90) is reported for gas phase ordinary water H 2 O and heavy water D 2 O. The methodology is optical refractive index gas metrology, operating at laser wavelength 633 nm and covering the range (293 < T 90 < 433) K and p < 2 kPa . A key output of the work is the determination of molar polarizabilities A R = 3.7466 (18) · [ 1 + 1.5 (6) × 10 - 6 (T / K - 303) ] cm 3 · mol - 1 for ordinary water, and A R = 3.7135 (18) · [ 1 + 4.4 (10) × 10 - 6 (T / K - 303) ] cm 3 · mol - 1 for heavy water, with the numbers in parentheses expressing standard uncertainty. For heavy water, this work appears to be only the second gas phase measurement to date. For both ordinary and heavy water, this work agrees within 0.15 % with recent ab initio theoretical results for A R , but the comparison is affected by imperfect knowledge of dispersion. For ordinary water, the close agreement between the present work and theory suggests problems at the 2 % level in the low density limit of the reference formulation for refractivity. [ABSTRACT FROM AUTHOR]

The LF & HF voltage, current and microwave metrology section of the CSIR-National Physical Laboratory plays an imperative role in the metrological investigations in the country as it follows the lawful obligations of the NPL charter of developing and maintaining national standards of HF voltage, LF voltage and current, phasor measurement unit and microwave power parameters. For over three decades, the section has been religiously dedicated to performing national obligations and delivering national calibration, testing and measuring services. Still, there is inadequate awareness, insight and perception related to the role of metrological traceability, calibration and measurement capabilities (CMCs) to the clients, academia, industries and government laboratories. Hence there is a dire need to educate and provide the required information to the end users. Keeping this in mind, this paper provides necessary details of the facilities, technologies and CMCs of the section to the common masses. The International Bureau of Weights and Measures (Bureau International des Poids et Mesures) and Asia Pacific Metrology Programme key/supplementary comparisons are also described in the paper, which has helped the group improve and attain greater heights. [ABSTRACT FROM AUTHOR]

Isotopic measurements provide valuable information about the origin of greenhouse gases — as carbon dioxide levels increase, there is a corresponding shift towards lighter isotopic composition similar to that of fossil fuels. Detecting such isotopic shifts, however, requires extremely precise measurements, which must also be globally reproducible in order to make reliable policy decisions. This feature article outlines the collective search for the ideal standard for carbon isotope measurements since the 1950s. This tragicomedy of errors, if you wish, has strengthened the reliability of today's measurements and has taken us from fictional oceans, to toilet seat marbles, and complex mathematical conventions that separate data from reliable results. [ABSTRACT FROM AUTHOR]

Bifurcation of exceptional points (EPs), particularly higher-order EPs, can offer applications in metrology by amplifying sensitivity, but this method suffers from a tradeoff between sensitivity and robustness. To break this constraint, we experimentally introduce nonlinearity into the EP degeneracy lifting at the coupled electric resonators and observe a sixth-order nonlinear bifurcation which amplifies the sensitivity elevenfold compared to the conventional EP-based approach operating in the linear regime, while maintaining the degrees of freedom, thereby without cost in robustness. Moreover, we discover a chaotic dynamics near the EP due to the nonlinear contribution, which constitutes a distinct difference from the EP degeneracy lifting in the linear regime with random noise. Our study expands the scope of EP degeneracy lifting into nonlinearity, providing a paradigm to exploit the benefit of EPs. Bifurcation of exceptional points (EPs) could offer applications in metrology by amplifying sensitivity. The authors find that introducing experimentally nonlinearity can bifurcate the EP degeneracy lifting yielding an elevenfold sensitivity enhancement and a chaotic dynamics near the EP compared to the conventional EP-based approach in the linear regime. [ABSTRACT FROM AUTHOR]

The article considers compound metrological terms which are so deeply embedded in the mentality and practice of metrologists that the inadequacy of these terms is revealed only when some important problem cannot be solved. Under the moment-based approach to accuracy assessment, such a problem is the estimation of definitional uncertainty, while the term "direct measurement" evokes several paradigmatic associations: indirect, in a closed series, joint, and, other pseudomorphic measurements, similar in name form and different in definition. However, the errors in these measurements can no longer be estimated in the same way as the errors of measuring instruments are estimated. The semantics of compound terms containing the word "measurement" are analyzed. The author shows the role of the direct and figurative meanings of the word "measurement" in the problem related to the inadequacy of models, whose solution under the composition-based approach to accuracy assessment is indicated by the word "method" in the specified terms. Harmonizing the term "measurement problem" with the semantics of the word "problem" was the easiest way to correct this terminological misunderstanding. The inconsistency between the related terms "measurement method" and "method for solving a measurement problem" was also eliminated. [ABSTRACT FROM AUTHOR]

Quantum mechanics offers the possibility of unconditionally secure communication between multiple remote parties. Security proofs for such protocols typically rely on bounding the capacity of the quantum channel in use. In a similar manner, Cramér-Rao bounds in quantum metrology place limits on how much information can be extracted from a given quantum state about some unknown parameters of interest. In this work we establish a connection between these two areas. We first demonstrate a three-party sensing protocol, where the attainable precision is dependent on how many parties work together. This protocol is then mapped to a secure access protocol, where only by working together can the parties gain access to some high security asset. Finally, we map the same task to a communication protocol where we demonstrate that a higher mutual information can be achieved when the parties work collaboratively compared to any party working in isolation. [ABSTRACT FROM AUTHOR]

In this paper, asynchronous dual-wavelength phase-shift interferometry is used to calibrate a line structure of a step height of 400 mm nominally standard based on the ISO 5436 profile analysis. The Hamming window: band-pass filter is used to assign accurately the detected point edge from the intersection of the experimental line edge from its simulation. The shifted off-axis interferograms are captured and corrected from noise. The corrected interferograms are wrapped by using the four-frame algorithm. The extracted phases at each wavelength are subtracted and the obtained phase map is converted to a height map. Experimental results show that the detected point edge of the step height standard being measured is assigned at filter order N = 901, cut-off frequency f0 = 0.39, and frequency bandwidth fb = 0.25. [ABSTRACT FROM AUTHOR]

In 2019, the Event Horizon Telescope (EHT) released the first-ever image of a black hole event horizon. Astronomers are now aiming for higher angular resolutions of distant targets, like black holes, to understand more about the fundamental laws of gravity that govern our universe. To achieve this higher resolution and increased sensitivity, larger radio telescopes are needed to operate at higher frequencies and in larger quantities. Projects like the next-generation Very Large Array (ngVLA) and the Square-Kilometer Array (SKA) require building hundreds of telescopes with diameters greater than 10 ms over the next decade. This has a twofold effect. Radio telescope surfaces need to be more accurate to operate at higher frequencies, and the logistics involved in maintaining a radio telescope need to be simplified to support them properly in large quantities. Both of these problems can be solved with improved methods for surface metrology that are faster and more accurate with a higher resolution. This leads to faster and more accurate panel alignment and, therefore, a more productive observatory. In this paper, we present the use of binocular fringe projection profilometry as a solution to this problem and demonstrate it by aligning two panels on a 3-m radio telescope dish. The measurement takes only 10 min and directly delivers feedback on the tip, tilt, and piston of each panel to create the ideal reflector shape. Highlights: Current methods for measuring and aligning radio telescope dishes are insufficient for future astronomy requirements. We've developed a 3D scanning method for measuring full aperture dishes outdoors that is faster, easier, and more reliable than current methods. We demonstrated the method by aligning two panels on a 3-m dish to a high accuracy. [ABSTRACT FROM AUTHOR]

In this paper, a new deflectometry approach well suited for online inspection of specular reflective materials is proposed. Based on a simple hardware setup combining two linear light sources, a camera and a conveyor, our approach allows to detect, to localize, and to reconstruct in 3-D, surface aspect defects. It is easy to implement and particularly well suited for large objects in an industrial context (production line, for example). When the camera and light sources are fixed, the first step consists in calibrating the camera and estimating the light sources positions in the camera frame. Then, a full scanning of the object can be done, and the defects are detected in all images. In the last step, the defect is reconstructed in 3-D by slope integration. Thanks to a second light source added to the setup, the initial depth required by this kind of method is automatically estimated. Our approach has been tested in real experimental conditions with different plastic reflective parts and compared to the results provided by a metrology machine to validate the calibration and the reconstruction accuracy. The reconstructions of few millimeters defects on 4 different plastic parts show errors below 50 μ m. This accuracy meets the usual requirement in the industrial context as the 3D industrial metrology machine that we use to validate our method is more complex to handle with specular objects and has an accuracy of around 20 μ m. [ABSTRACT FROM AUTHOR]

This proposed paper delves into the challenges within the metrology sector and proposes innovative solutions employing cutting-edge technologies such as AI and Big Data. The aim is to establish an AI-enabled National Digital Grid for Metrology in the context of India. In our modern digital landscape, technologies like Big Data, AIoT (AI + IoT), Cloud Computing, and Blockchain significantly influence individuals, objects, and global economies. Metrology, as the scientific study of measurement, is not exempt from these technological impacts and encounters numerous challenges in its digital evolution. As an essential component for international trade, the development of its digital quality infrastructure is imperative, prompting discussions on the numerous challenges faced in this realm. The paper explores key findings and contributions concerning the digital transformation of metrology and its significance for the sector's advancement. [ABSTRACT FROM AUTHOR]

The detection of weak time-dependent alternating signals in a strongly noisy background is an important problem in physics and a critical task in metrology. Quantum lock-in amplifier can extract alternating signals within extreme noises by using suitable quantum resources, which has been widely used for magnetic field sensing, vector light shift detection, and force detection. In particular, entanglement-enhanced quantum lock-in amplifier can be realized via many-body quantum interferometry. The many-body lock-in measurement provides a feasible way to achieve high-precision detection of alternating signals, even in noisy environments. In this article, we review general protocol, experiment progresses and potential applications of quantum lock-in measurements. [ABSTRACT FROM AUTHOR]

Network theory has fundamentally transformed our comprehension of complex systems, catalyzing significant advances across various domains of science and technology. In spectroscopic networks, hubs are the quantum states involved in the largest number of transitions. Here, utilizing network paths probed via precision metrology, absolute energies have been deduced, with at least 10-digit accuracy, for almost 200 hubs in the experimental spectroscopic networks of H216O and H218O. These hubs, lying on the ground vibrational states of both species and the bending fundamental of H216O, are involved in tens of thousands of observed transitions. Relying on the same hubs and other states, benchmark-quality line lists have been assembled, which supersede and improve, by three orders of magnitude, the accuracy of the massive amount of data reported in hundreds of papers dealing with Doppler-limited spectroscopy. Due to the omnipresence of water, these ultraprecise line lists could be applied to calibrate high-resolution spectra and serve ongoing and upcoming space missions. Ultraprecise spectral line lists of molecules such as water, omnipresent in various environments, can be used to calibrate high-resolution spectra, which is particularly relevant for exoplanet transit observations. Here, the authors use measured spectra and network theory to achieve ultraprecise characterization of H216O and H218O hubs, the most relevant quantum states within a spectroscopic network. [ABSTRACT FROM AUTHOR]

Absolute measurement has consistently been the primary focus in the development of precision linear and angular displacement measurements. The scheme design of binary zero position codes is an important factor for absolute measurement. Designing and optimizing high-bit zero position codes with over 100 bits face considerable challenges. Simultaneously, the working parameters of zero position codes [unit code width (b), distance (d), and yaw angle (α)] remarkably affect their post-installation performance, particularly in absolute positioning and limit code application in multi-degree-of-freedom measurement schemes. This study addresses these challenges by proposing a design method for zero position codes that considers diffraction based on generative adversarial networks and aims to explore a design with increased efficiency and accuracy as well as optimization for high-bit zero position codes. Additionally, the tolerance range of zero positioning performance for each working parameter is examined. By leveraging the adversarial network structure, this study generates the optimization of a 150-bit code and processes the tests of the zero position code by using simulation results. The following working parameter ranges for code design are recommended on the basis of theoretical and experimental results: b greater than 10 μm, d and α within 1000 μm and 3490 μrad, and avoidance of intervals with sharp changes in the full width at half maximum. The proposed code design and parameter optimization lay a solid foundation for research and engineering applications in absolute measurement field and have considerable potential for generalization and wide applicability. Highlights: This article is the first to use deep learning adversarial networks to generate absolute positioning binary codes; This article analyzes the influence of installation and unit code width parameters on positioning performance based on the principle of diffraction propagation and the positioning performance labels; This article establishes a comprehensive model (ZD-GAN) for generating absolute positioning codes through deep learning. The model can select the best absolute positioning code and provide guidance for the optimal installation and usage parameter range. [ABSTRACT FROM AUTHOR]

To design the complex of diagnostics and technical systems of the T-15MD tokamak, a three-dimensional CAD model is used, which includes all structural elements of the tokamak and surrounding heating and diagnostic systems, technical systems such as vacuum pumping and data acquisition systems, etc. Use of the CAD model allows us to take into account the relative location of adjacent systems and the tokamak geometry and integrate newly designed systems. This approach is applied to the design of ITER and used for the first time for Russian tokamaks. In order to provide the most comprehensive matching of the CAD model to the real T-15MD it is necessary to perform verification of the CAD model. This paper presents a method of the verification of the CAD model of T-15MD tokamak complex based on the data of the laser geodesic scanning and the results of assessing the accuracy of the performed work. [ABSTRACT FROM AUTHOR]

The growing demands of optical systems have led to increasingly complex aspheres and freeforms. In this paper, an established measurement system in asphere production, which is also a promising approach in high-precision freeform metrology, is presented. It is based on a scanning-point multiwavelength interferometer approach. The scanning principle enables great flexibility, reduces setup time and costs, and has almost no limitations in spherical departure. Due to the absolute measurement capability, the utilized multiwavelength approach is beneficial for segmented, annular, and discrete surfaces, which are common designs of modern applications’ optical elements. The metrology system enables measurements on a nanometer scale on a great variety of apertures—from 1 to 1000 mm. Recently, a new short-coherence multiwavelength interferometer operating in the visible domain has been developed. It enables the high-precision measurement on silicon-coated surfaces, which can be found in space applications and are also commonly used for extreme-ultraviolet (EUV) lithographic setups, which will be used as an example throughout this work. Owing to the large absolute measurement capability, applied grating structures for suppressing infrared light in the EUV process can easily be measured. This paper summarizes the basic working principles of the proposed metrology system, explains the special requirements for different fields of application, highlights the capabilities of the visible multiwavelength approach, and shows the measurement results.Highlights: Modern applications, like extreme-ultraviolet lithographic setups, require new and flexible metrology tools. A scanning-point interferometer, working in the visible domain, is presented. The first measurement results on demonstrators prove the capability. [ABSTRACT FROM AUTHOR]

The article considers artificial intelligence as one of the main elements of digital transformation and promising directions of its application in metrology. The main attention is paid to the use of artificial neural networks as part of measuring instruments and measuring systems for obtaining measurement results in cases where the measurement function is unknown, insufficiently defined or too complex for algorithmic formalization. It is noted that in practice problems with a partially uncertain function, when, in addition to the deterministic basis, there is an additional unknown component that has a significant impact on the measurement result, often arise. A simulation experiment was carried out to solve such a measurement problem using a neural network model. In the experiment, a measurement function with a linear deterministic basis and an additional nonlinear component, which is approximately 10% of the relative standard deviation and is a priori unknown (according to the conditions of the problem), was used. The experimental results confirmed the practical possibility and high efficiency of using artificial neural networks to solve such measurement problems. The neural network model, under conditions of a noisy training dataset corresponding to real measurement conditions, almost completely restored the measurement function, despite the fact that the neural network model used was linear, and the additional component of the measurement function was nonlinear. In this experiment, due to the use of a neural network, the accuracy of measurements was improved by approximately an order of magnitude. Access to the machine code that implements this simulation experiment is provided. [ABSTRACT FROM AUTHOR]

An n (p , T 90) measurement suite is reported for the gases helium, argon, and nitrogen. The methodology is optical refractive-index gas metrology, operating at laser wavelength 633 nm and covering the temperature range (293 < T < 433) K and pressures p < 0.5 MPa . The measurement suite produces several things of thermophysical interest. First, the helium dataset deduces the effective compressibility of the apparatus with a relative standard uncertainty of 1.3 × 10 - 4 . Next, the argon dataset determines T - T 90 with a relative standard uncertainty of about 3 μ K · K - 1 . (The implementation is relative primary thermometry; T - T 90 is the difference between thermodynamic temperature and ITS-90.) Finally, the nitrogen dataset estimates the temperature dependence of polarizability within 3.5 % relative standard uncertainty. As a by-product of the nitrogen and argon measurements, values of the second density virial coefficient B ρ (T) are derived with uncertainties smaller than those of previous experiments. More broadly, the work enables conversion of a measured refractivity at known temperature to optical pressure within 3.5 μ Pa · Pa - 1 across the stated range, albeit traceable to the diameter of a piston-gage. [ABSTRACT FROM AUTHOR]

The term 'Quality Infrastructure' refers to the public and private institutional framework for metrology, standardisation, accreditation, and services relating to conformity assessment such as testing, calibration, inspection and verification that fosters trust in global commerce and helps to safeguard consumers and the sustainability of the environment. The National Physical Laboratory, several Designated Institutes, the British Standards Institution, the Office for Product Safety and Standards, and the United Kingdom Accreditation Service are all part of the United Kingdom Quality Infrastructure. As a part of the National QI of the UK, these organisations are responsible for providing traceability to national standards of measurement and regulating standardisation, testing, certification, and accreditation. These organisations are essential in assisting industries with developing, innovating, and commercialising their goods and services. Standards supported by accredited conformity assessment are an essential part of modern economic infrastructure and assist significant economic growth. This paper provides a succinct overview of the UKQI and its importance for national growth. Further, an overview of the UKQI institutional structure from both national and international perspectives is discussed. This study should be useful globally to government agencies, businesses, academia, and other organisations as a reference source for future policy decisions related to a robust QI. [ABSTRACT FROM AUTHOR]

The critical aspect in the field of single-photon metrology is to measure the detector efficiency with the lowest possible uncertainty and reproducibility. The developments in quantum technologies have paved the way for applications such as quantum imaging and quantum information processing, including quantum computing and quantum communications proving superior to the conventional technologies currently in use. Superconducting Nanowire Single-Photon Detectors (SNSPDs) are one of the key elements in these applications and are preferred over similar devices due to their better performance parameters. The instrumentation used for characterizing single-photon detectors must be precise and reliable so that no optical event gets missed. Here, we present an optical setup based on the 2nd-order correlation measurement, developed to characterize single-photon detectors at visible to near-infrared wavelengths. Each device used in the setup has been thoroughly characterized, and their response under different operating conditions has been studied. In the setup, a few photons generated by attenuating a laser are split by a 50:50 fiber beam splitter and sent to two single-photon detectors. A correlation card measures the coincidences. [ABSTRACT FROM AUTHOR]

In the present scenario, the 3D reconstruction of a scene plays a vital role in many manufacturing industries. In this work, an attempt was made to develop a machine vision system under shape from focus technique for surface reconstruction with active illumination pattern projection. The accuracy of the reconstruction of the proposed method was investigated and compared with the traditional approach. It was found that the developed approach can provide enhanced accuracy owing to the improved texture of the samples by additional pattern illumination and removing the noise content by a dynamic window size median filter. Among all shapes considered, Hemisphere which has more height and curved feature performs better reconstruction. [ABSTRACT FROM AUTHOR]

Industry 6.0 is viewed as a futuristic industrial evolution. It aims to set the synergy between man and robot by providing the wealth affluence away from the trade, and customers solutions that would provide progress to the world in every field across all planetary boundaries. Industry 6.0 comprises numerous promising technology such as quantum computing, artificial intelligence, machine learning, cloud computing, and quantum artificial computing. These technologies have the massive capabilities to help the legal industry, metrology industry and many other organizations attain their goals by delivering excellent and best-suited insights. In the future, these technologies will assist the lawmaker and jurisprudence in improving the old law justice system into the advanced one. In this article, we first introduce a glimpse of industry 6.0 from the outlook of legal information, digital transformation in metrology, and strength, limitation, opportunities, and threat analysis in brief. Then we discuss key technologies of industry 6.0, framework of legal informative, a futuristic model for a legal informatics system based on quantum-based AI, machine learning, and digital legal metrology and its challenges in adoption in regard's Industry 6.0. In subsequent sections, we discussed requirements, challenges, and progress in developed countries, preparedness of academia and industry in India. Then, we brief challenges for legal metrology in the future, opportunities for legal metrology in future legal challenges faced by lawyers and legal metrology, limitations of the study, research implication, and conclusion. Finally, the finding shows that industry 6.0 technologies have enormous capabilities to bring a revolutionary change in the legal industry but are present in the new born growth stage. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) imaging of thin, extended specimens at nanometer resolution is critical for applications in biology, materials science, advanced synthesis, and manufacturing. One route to 3D imaging is tomography, which requires a tilt series of a local region. However, capturing images at higher tilt angles is infeasible for such thin, extended specimens. Here, we explore a suitable alternative to reconstruct the 3D volume using a single, energy-filtered, bright-field coherent image. We show that when our specimen is homogeneous and amorphous, simultaneously inferring local depth and thickness for 3D imaging is possible in the near-field limit. We demonstrated this technique with a transmission electron microscope to fill a glaring gap for rapid, accessible 3D nanometrology. This technique is applicable, in general, to any coherent bright field imaging with electrons, photons, or any other wavelike particles. The authors experimentally demonstrate with a transmission electron microscope that single-shot 3D imaging is possible in the near-field limit, by simultaneously inferring local depth and thickness. The proposed reconstruction method uses priors from the homogenously amorphous specimen, and it can be extended for imaging multi-layered samples. [ABSTRACT FROM AUTHOR]

The relevant problem of analyzing the features of measurement systems and their metrological support is formulated. Promising areas for the development of measurement systems, including virtual systems, are considered. The article analyzes such development areas as remote and synchronized vector measurements, cloud technologies, the Internet of Things, big data, and artificial intelligence. Several innovative solutions employing both biosensors and hybrid metrology are described (introduction of structural redundancy into measurement systems, as well as the introduction of temporal and algorithmic redundancies into the software of measurement systems). It is shown that the integration of component functions objectively complicates the identification of measurement systems in complex technical systems, yet providing new possibilities for technical systems with measurement functions. The following areas for improving the metrological support of measurement systems are analyzed: self-diagnostics and self-monitoring; remote and automated calibration and verification; use of digital twins, big data, and artificial intelligence; establishment of adaptive calibration and verification intervals. The study reveals the need to minimize bureaucratic procedures and automate metrological procedures while showing practicability in switching from periodic to adaptive procedures requiring no human involvement. [ABSTRACT FROM AUTHOR]

Background: Reliably measuring sharp details in displacement and strain maps returned by full-field measurement techniques remains an open question in the photomechanics community. Objective: The primary objective of this study is to improve and fine-tune a deconvolution algorithm in order to limit the blur that obscures the details in displacement and strain maps. Methods: Checkerboard patterns are used and processed with a spectral method, namely the Localized Spectrum Analysis (LSA), and the raw maps returned by this technique are deconvolved. The influence of various settings on the quality of the results is studied by using synthetic images deformed through a well-vetted reference displacement field. Results: It is shown that linking the size of the analysis window used in LSA on the one hand, and the size of the second derivative kernel employed in the deconvolution algorithm on the other hand, ensures the convergence of the deconvolution algorithm in all cases. This was not the case with the initial version. The ratio between these sizes, which optimizes the metrological performance of LSA followed by deconvolution, is identified. The influence of the sampling density of the checkerboard pattern in the images is also examined. The efficiency of the deconvolution algorithm employed with optimized settings is illustrated with strain maps obtained on two specimens, one in shape memory alloy, and the other in wood. Conclusions: It is shown in this study that deconvolution with optimized settings is an effective tool to enhance small and sharp details in strain maps obtained with LSA. [ABSTRACT FROM AUTHOR]

We present a hybrid quantum-classical variational scheme to enhance precision in quantum metrology. In the scheme, both the initial state and the measurement basis in the quantum part are parameterized and optimized via the classical part. It enables the maximization of information gained about the measured quantity. We discuss specific applications to 3D magnetic field sensing under several dephasing noise models. Indeed, we demonstrate its ability to simultaneously estimate all parameters and surpass the standard quantum limit, making it a powerful tool for metrological applications. [ABSTRACT FROM AUTHOR]

The presented literature review was prepared by a team of authors united by the Program and Organizing Committees of the "Optical Reflectometry, Metrology, and Sensing" (ORMS) conference in 2023. It is intended to assess the state and prospects in this area for the coming years. The review covers the following topics: distributed acoustic sensors, fiber-optic measurement systems based on Brillouin scattering, research methods based on the principles of optical reflectometry in the frequency domain, and low-coherence approaches to distributed temperature and strain monitoring. [ABSTRACT FROM AUTHOR]

Virtual reality tracking devices are being investigated for application to motion tracking of robots, human bodies, indoor drones, mobile systems, etc., but most studies so far have been limited to performance analysis of commercialized tracking devices in static conditions. This paper investigated methods for improving the measurement accuracy of dynamic positioning and orientation of the HTC tracker. The signals from the photodiodes in the tracker were extracted and fused together, as well as with external Inertial Measurement Units (IMUs) signals using the Extended Kalman Filter (EKF) and the Unscented Kalman Filter (UKF). Multiple base stations, trackers and IMUs were applied to evaluate the measurement accuracy. Multiple paths were used to test different dynamic operating conditions. The results show that the proposed tracking system can improve accuracy by up to several mm by using the UKF as opposed to the EKF algorithm, increasing the number of base stations, increasing the number of trackers and fusing IMUs. [ABSTRACT FROM AUTHOR]

In the present paper, the digital transformation in metrology is discussed, which is revolutionizing the world and is one of the most interesting developments in science & technology today. The study also discusses, how current technologies like Artificial Intelligence, the Internet of Things, Cloud computing, and more significantly digital twins would become synonymous with digital metrology, thus bolstering the future of manufacturing industries. The basic objective of any digital transformation initiative is to enhance the current processes, while each one will have its own unique set of objectives. As metrology is considered as the main pillar of Quality Infrastructure (QI), the digital transformation of metrology requires a holistic approach for all stakeholders working within the advanced QI of a country or economy. [ABSTRACT FROM AUTHOR]

Composite voltage test according to IEC 60060-1:2010 is a test method where impulse high voltage is applied simultaneously with alternative voltage (AC) or direct voltage (DC) to the same terminal of the test object.. The equipment used in the DC and AC high-voltage grids has some special test procedures to be fulfilled under not only DC, AC, and lightning impulse (LI) but also the composite voltages having impulse high voltages superimposed over HVDC and HVAC. In addition, the IEC 61083–1 standard allows low-voltage measuring instruments to be qualified by comparison to approved reference calibrators traceable to the international system of units. The measuring instruments used in this test usually calibrated by the reference systems separately for DC, AC and LI. But there is a metrological gap related to the calibration of these measuring equipment with reference composite signals. In this work, to provide traceability about the composite high-voltage measuring system, reference composite voltage waveforms for LI voltages superimposed over DC and AC signals have been designed up to 300 V for impulse voltage and 1000 V for AC and DC voltage using with passive protection components. On the AC and DC voltage source side of the setup, the reference voltage calibrator with the 10 µV/V uncertainty has been used and a reference calculable impulse voltage calibrator has been used as an impulse voltage source with the 1 mV/V peak voltage uncertainty and 10 ms/s time parameters uncertainty. The simulation results of calibrator design and comparison measurements of the real circuits were presented for LI superimposed on DC and AC. [ABSTRACT FROM AUTHOR]

Over the past few decades, the rapid and expanding usage of high-pressure technologies in science and engineering has prompted researchers to focus on developing better instruments and technologies with improved measurement uncertainties for various applications. Such efforts resulted in the development of new and advanced measurement techniques and standards to address calibration challenges and provide traceability to users. In the present study, an indigenous strain gauge-type pressure transducer has been designed, developed, tested, and calibrated for pressure measurements up to 1000 MPa. The sensing element's cylindrical shape was used, providing a cost-effective and straightforward approach for designing a pressure transducer over a wide pressure range. It also ensures a leak-proof and locked connection to the external environment, with no over-constrained contacts. The calibration and performance checking of the pressure transducer has been carried out using the national primary pressure standard with the internationally accepted calibration procedure. The transducer response under pressure is highly linear during its performance evaluation. As a result, the transducer performs satisfactorily within the reasonable measurement uncertainty of 0.5% of the full scale. The pressure transducer developed may help trace the user industries and calibration laboratories in the high range of pressure measurement and serve as a pressure transfer standard. [ABSTRACT FROM AUTHOR]

Three-dimensional printing and casting materials were analyzed by prompt gamma-ray activation analysis (PGAA) to determine their suitability as human tissue surrogates for the fabrication of phantoms for medical imaging and radiation dosimetry applications. Measured elemental compositions and densities of five surrogate materials simulating soft tissue and bone were used to determine radiological properties (x-ray mass attenuation coefficient and electron stopping power). When compared with radiological properties of International Commission on Radiation Units and Measurements (ICRU) materials, it was determined that urethane rubber and PLA plastic yielded the best match for soft tissue, while silicone rubber and urethane resin best simulated the properties of bone. [ABSTRACT FROM AUTHOR]

Quantum metrology employs nonclassical systems to improve the sensitivity of measurements. The ultimate limit of this sensitivity is dictated by the quantum Cramér–Rao bound. On the other hand, the quantum speed limit bounds the speed of dynamics of any quantum process. We show that the speed limit of quantum dynamics sets a fundamental bound on the minimum attainable phase estimation error through the quantum Cramér–Rao bound, relating the precision directly to the underlying dynamics of the system. In particular, various metrologically important states are considered, and their dynamical speeds are analyzed. We find that the bound could, in fact, be related to the nonclassicality of quantum states through the Mandel Q parameter. [ABSTRACT FROM AUTHOR]