The measurement and control of trace moisture is an important procedure to maintain and secure the quality and safety of pipeline systems for natural gas. The natural gas mix typically comprises methane, ethane, propane, some higher hydrocarbons, carbon dioxide and nitrogen. It is too impractical to perform additional calibrations of trace moisture measurement every time the combination of gas components

Four-quadrant plane capacitive sensors with electrodes made by thick metal plates were used in a novel configuration of a bridge-based circuit for measurement of both displacement and small angles over two axes. Their design, fabrication and testing by means of a specifically designed differential set-up is presented and discussed in terms of the measurement model, considerations of signal recovery

This paper presents the results of studying the shielding effect of a vertical moving shutter micromachined electric field mill. In this design, a set of interdigital sensing electrodes are located in the same plane as the moving shutter, with the shutter’s vertical motion enabling modulation of the sensed electric field. The effects of various geometrical parameters of the shutter, including the spacing

In this study, an ultrasonic method for characterizing thin films based on the dispersion of the first Rayleigh mode is presented. The principle of surface acoustic waves (SAW) generation using a broadband transducer and their detection is detailed. It is shown that over a frequency range between 20 MHz and 125 MHz, SAWs are sensitive to fine deposits and the attenuation is reasonable thus enabling

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Three-dimensional (3D) similarity transformation is popularly applied for measurement datum transformation. In this study, a seamless partial errors-in-variables (EIV) model with equality constraints is established to describe the universal 3D similarity transformation problem (with arbitrary rotation angles and scale factor). Unlike the traditional transformation model, all of the random errors in

The determination of the number of active modes is always an obstacle to the identification of dynamic systems. To tackle this issue, a new blind modal estimation method is proposed through which the number of active modes does not need to be presupposed, even in underdetermined blind source separation cases. Firstly, the spatial time–frequency distribution matrices are constituted from the smoothed

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This work aims to present a method for simultaneously estimating the thermal conductivity, k , and specific heat, c p , in samples of stainless steel 304 and cemented carbide by accounting the imperfect thermal contact at the heater–sample interface. A transient one-dimensional heat conduction model with constant thermal properties is used. The metallic sample is placed in the middle of a polyimide

A 3D volumetric technique for measuring the evolution over time of the kinematic and geometric characteristics of the bubble population in multiphase flows at moderate void fraction is here proposed. The method is based on a shadowgraphy approach and requires a set of calibrated and synchronized cameras, each placed in front of a bright screen. Synchronized, 2D images of the bubbly flow are analyzed

Multiplexed optical fibre sensors were embedded into a carbon-fibre-reinforced-preform during the industrial production of a full-sized, one-piece tail cone assembly for a regional jet aircraft. Optical fibre Fresnel sensors monitored both the infusion of the resin, via measurement of the refractive index-dependent attenuation in the reflected light signal, and the degree of cure of the resin, via

Modal parameter identification is a useful tool to reveal natural vibration characteristics in dynamic design and analysis. Due to the influence of closely spaced modes with close frequencies and large dampings, identification accuracy using traditional Hilbert–Huang transform is always unsatisfactory, since the deadline requirement of neighboring intrinsic mode functions cannot be satisfied when the

Rolling element bearings are commonly used in rotary mechanical and electrical equipment. According to investigation, more than half of rotating machinery defects are related to bearing faults. However, reliable bearing fault detection still remains a challenging task, especially in industrial applications. The objective of this work is to develop a smart sensor-based monitoring system for vibration

We demonstrate a new type of fiber in-line Mach–Zehnder interferometer (MZI). The device is fabricated by firstly inscribing a ring structure surrounding the fiber core at the ends of two single-mode fibers using a femtosecond laser micromachining technique and then fusion-splicing the two fibers with end structures. Due to the high temperature produced in the fusion splicing process, the ring structure

An optical in-fiber Mach–Zehnder interferometer based on thin core fiber for liquid level sensing is proposed and experimentally demonstrated. The sensor head is composed of a single-mode taper-thin core taper single-mode fiber structure constructed via fusion splicing. The operational principle relies on the sensitivity of intermodal interference to liquid level variation; this is achieved by employing

High-frequency oscillations and high surface aeration, induced by strong turbulence, make water depth measurement for hydraulic jumps a persistently challenging task. The investigation of hydraulic jump behaviour continues to be an important research theme, particularly with regards to the stilling basin design. Reliable knowledge of time-averaged and extreme values along a depth profile can help develop

Power density is an important attribute for aviation hydraulic pumps, which can greatly benefit from improving rotational speed. However, cavitation tends to occur in the pump at high rotational speeds, thus decreasing its volumetric efficiency and lifetime. Therefore, cavitation identification is essential and urgent for high-speed aviation hydraulic pumps. In this paper, we propose a real-time method

In previous work, we developed a calibration apparatus for use with contact surface thermometers. In this apparatus, the temperature of the upper surface of a copper cube was used as reference surface temperature. In this new study, uncertainty components due to environmental conditions in the measurement space were estimated by measuring the temperature of the upper surface of the calibration apparatus

Digital imaging array technology and processing power are continuously improving and have reached a state where 4-dimensional (i.e. time-resolved 3C-3D) digital holographic PIV/PTV (4D-DHPIV/PTV) methods can be considered for macro fluid mechanics and turbulence investigations. This paper presents an in-line 4D-DHPIV/PTV methodology, which in addition to including the standard digital hologram reconstruction

A new automated method capable of accurately identifying bursting periods in single-point turbulent velocity field records is presented. Manual selection of the method sensitivity ##IMG## [http://ej.iop.org/images/0957-0233/31/10/105801/mstab912bieqn1.gif] {$\left( {{\tau ^*}} \right)$} and threshold ##IMG## [http://ej.iop.org/images/0957-0233/31/10/105801/mstab912bieqn2.gif] {$\left( {{\varepsilon

A direct, shape- and scale-independent digital image measurement method of the surface area (SA) of individual objects is proposed. The algorithms presented herein utilize the brightness histogram of 8-bit greyscale images, and thus are referred to as a brightness histogram surface area measurement algorithm (BHSAMA). The proposed SA measurement technique allows the uncertainty of the single measurement

The wavelength tuning characteristics of a widely tunable modulated grating Y-branch laser operating in a large temperature range was investigated experimentally. The linear fine-tuning was realized by sweeping the phase region current, and the fine lookup table was created with a high resolution of less than 0.1 pm. We found experimentally that the tuned wavelength has an excellent linear correspondence

The design, optimization and demonstration of a compact, single-ended laser absorption sensor based on a diffuse-wall-reflected signal is presented for temperature and H 2 O concentration measurements in a kerosene-fuelled aero-combustor. The challenges of laser measurements in such harsh, practical combustion environments involve strong beam-steering, low signal-to-noise ratio (SNR), and constrained

Oxidation of metals can provide a functional oxide film or an oxide layer that can lead to material degradation causing performance limiting concerns. Because of the technological and economic impacts of oxidation, understanding early-stage oxidation growth and its mechanisms is of high importance. Unfortunately, poor empirical data during early-stage oxidation has left our current understanding of

Early fault diagnosis is a hotspot and difficulty in the research of mechanical fault diagnosis. An early fault diagnosis method based on the orthogonal neighborhood preserving embedding and Adaboost_SVM algorithm for rolling bearing early fault diagnosis is proposed in this paper. Firstly, the vibration signals of rolling bearings are measured online. The correlation coefficients between the early

We present the principle and the experimental verification of a distance measurement method based on the propagation of terahertz waves. The method relies on modulating the amplitude of a resonant-tunneling-diode (RTD) oscillator used as terahertz-wave source and on measuring the phase of the detected wave by applying a quadrature mixing technique. The distance measurement is found to have a residual

A high-precision confocal auto-collimation decentration measurement method (CADM) for spherical lens is proposed. In comparison with the traditional auto-collimation method, this method employs confocal technology to accurately locate the center of the tested lens, which reduces the focusing error. The radius of curvature and center bias measurements are integrated into one measurement system, which

Optical inspection of periodic nanostructures is a major challenge in the semiconductor industry due to constantly decreasing critical dimensions. In this paper we combine coherent Fourier scatterometry (CFS) with a sectioning mask for subwavelength grating parameter determination. By selecting only the most sensitive regions of the scattered light in the Fourier plane, one can retrieve grating parameters

A turbulent boundary layer is a ubiquitous element of fundamental and applied fluid mechanics. Unfortunately, accurate measurements of turbulent boundary layer parameters (e.g. friction velocity ##IMG## [http://ej.iop.org/images/0957-0233/31/9/094011/mstab8904ieqn1.gif] {$u_\tau$} and wall shear τ w ) are challenging, especially for high-speed flows (Smits et al 2011). Many direct and/or indirect diagnostic

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Line-laser 3D scanning is a novel and promising automation technique for turbine blade inspection. One key task encountered in line-laser 3D scanning is centerline extraction of the laser stripes. In some regions, there is asymmetry of the line profiles caused by high curvature, such as the leading and trailing edges of a blade. According to the asymmetric Gaussian distribution line profile, this paper

Data-driven decompositions of particle image velocimetry (PIV) measurements are widely used for a variety of purposes, including the detection of coherent features (e.g. vortical structures), filtering operations (e.g. outlier removal or random noise mitigation), data reduction and compression. This work presents the application of a novel decomposition method, referred to as multiscale proper orthogonal

This study quantitatively derives a principle for super-high-accuracy angular indexing using an index table formulation, and verifies it in a mathematical simulation. An index table is a rotary table installed on a machine tool. Its main function is to fix the angle position of the rotational shaft. The angle position is measured by a rotary encoder built into the rotary table. The rotary encoder is

Considering the remarkable progress of the Galileo constellation in recent years, the main objective of this study is to evaluate the performance of dual- and single-frequency Galileo-based precise point positioning (PPP), and its contribution to GPS and Galileo integration with different precise products generated by four analysis centers (ACs) within the context of the Multi-GNSS Experiment (MGEX)

We describe an alternative stereo calibration method for stereo-digital image correlation (stereo-DIC) using computer-simulated speckle-pattern calibration targets and a DIC-based control points matching technique. The present work refines and extends the recently proposed camera calibration method to stereo calibration, which is an essential part of stereo-DIC measurement. In the proposed calibration

Measuring the properties of scattered light is central to many laser-based gas diagnostic techniques, such as filtered Rayleigh scattering (FRS). Alongside the measurements, a model of the scattered light’s spectral lineshape is often used to extract quantitative information about the flow field like pressure, temperature, and velocity. In particular, the Tenti S6 or S7 model are frequently used to

The positioning accuracy of machine-tool tables used for translatory movement and coordinate measuring machine carriages requires improvement. Transmission and blocking of light can be realized by combining a transmissive liquid crystal and a polarizing plate. In this study, this technique was applied to a laser interferometer to realize selective multi-degree-of-freedom motion measurement using one

Modern microscopes and profilometers such as the coherence scanning interferometer (CSI) approach sub-nm precision in height measurements. Transfer standards at all measured size scales are needed to guarantee traceability at any scale and utilize the full potential of these instruments, but transfer standards with similar characteristics upon reflection to those of the measured samples are preferred

Fracture non-union, the failure of a bone fracture to bridge, occurs in roughly 5%–10% of treated fractures and requires lengthy and expensive follow-up interventions. A significant body of research has investigated the efficacy of low-magnitude, high-frequency (LMHF) vibration as a treatment for femoral non-unions through the use of whole-body vibration. This work presents a novel piezoelectric fixation

A linear axis is the key component of several mechanical machines, especially of computer numerical control machine tools. The simultaneous measurement of the geometric motion errors of a linear axis is indispensable to compensate the machine errors, which improves the accuracy of machine tools. The principle of laser collimation is widely used for measuring the multi-degree-of-freedom (MDOF) geometric

Space-time image velocimetry (STIV) is a well-established image-based technique for measuring river surface flow from videos or image time series. Because the fundamental measurement mechanism is relatively simple, STIV has been used widely in research and for practical purposes in Japan and other countries. The advantage of STIV over other imaging techniques such as large-scale particle image velocimetry

Recently metrological atomic force microscopes (metrological AFMs) have been used for surface roughness measurements. The National Metrology Institute of Japan (NMIJ), AIST, provides a profile surface roughness calibration service using a metrological AFM based on ISO 19606:2017. This international standard requires evaluation of probe-tip diameter D and error in roughness measurements by using a standard

The nanoparticle phenomena concern three-dimensional motion in a fluid in which the nanoparticles move at ultra-high-speed with Brownian motion. However, current commercial methods for nanoparticle position tracking are only able to determine a two-dimensional position, and are not able to define the longitudinal axis Z as the third dimension. We have therefore proposed a method and have observed the

In the analysis of Lagrangian particle tracking data, ensemble averaging with spatial bins is used to generate Eulerian flow statistics. Due to the scattered nature of the particles over independent snapshots, the possible spatial resolution is directly dependent on the measured particle position accuracy and the amount of available data. This requires a balance between convergence of the underlying

Feature learning is an integral part of intelligent fault diagnosis. Sparse feature learning methods have been shown to be effective in learning discriminative features. To learn features with optimal sparsity distribution, an unsupervised sparse feature learning method called variant sparse filtering is developed. Variant sparse filtering uses a sparsity parameter to determine the optimal sparse feature

To achieve better fault diagnosis of rotating machinery, this paper presents a novel intelligent fault diagnosis model based on singular value manifold features (SVMF), optimized support vector machines (SVMs) and multi-sensor information fusion. Firstly, a new fault feature named SVMF is developed to better represent faults. SVMF is acquired by extracting manifold topology features of the singular

For use in a low-temperature region below the triple point of water (TPW), the National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (NMIJ/AIST) developed a precise comparison system of capsule-type standard platinum resistance thermometers (CSPRTs) for dissemination of the International Temperature Scale of 1990 (ITS-90). This study compared eight

When measuring the roughness of rough surfaces, the limited sizes of scanned areas lead to its systematic underestimation. Levelling by polynomials and other filtering used in real-world processing of atomic force microscopy data increases this bias considerably. Here a framework is developed providing explicit expressions for the bias of squared mean square roughness in the case of levelling by fitting

The microwave cavity perturbation method is widely used for material parameter measurements in connection with small homogeneous samples. Its applicability to larger and inhomogeneous samples is uncertain, but highly desirable in connection with the in- situ condition monitoring of chemical reactors. We have investigated the problem of the reconstruction of axially inhomogeneous permittivity distributions

We propose a simulation-assisted linear-inversion method to estimate heat intensity generated at a fatigue crack during vibrothermographic nondestructive evaluation. In vibrothermography, mechanical excitation is applied to a test specimen, and the contacting crack faces generate heat which flows to the surface and can be detected by an infrared camera. The heat intensity generated at the crack is

Processing techniques for particle-based optical flow measurement data such as 3D particle tracking velocimetry (PTV) or the novel dense Lagrangian particle tracking method ‘Shake-the-Box’ (STB) can provide time-series of velocity and acceleration information scattered in space. The following post-processing is key to the quality of space-filling velocity and pressure field reconstruction from the

This paper presents an improved data processing method, which is referred to as the tracking intersection method, for a fibre-based dual-detector differential chromatic confocal probe with a mode-locked femtosecond laser source. In the dual-detector differential confocal system, two fibre detectors of an optical spectrum analyzer are employed to detect the spectra of the confocal signals. One of the

Powder bed-based additive manufacturing has become increasingly important for industrial applications. In the light of this, qualitative considerations such as the geometrical accuracy, the resulting mechanical properties, and the surface quality of additively manufactured parts must be taken into account. Optical measuring techniques such as confocal laser scanning microscopy, fringe projection and

A novel resonance method for determining the complex permittivity of materials in the X-band is proposed. A distinctive feature of this method is that the sample under test, located in a radio-transparent isotropic and homogeneous dielectric matrix, is both a local inclusion and the excitation element of the resonance in the microwave module ‘waveguide–dielectric matrix–inclusion’. The complex permittivity

Atomic force microscopy (AFM) often relies on the assumption that cantilever bending can be described by simple beam theory and that the displacement of the tip can be evaluated from the cantilever angle. Some more advanced metrological instruments use free-space or fibre interferometers for measuring the position of the cantilever apex directly, thereby simplifying the metrology traceability chain

The measurement of trace moisture is important in industry to maintain the quality and yield of products, such as semiconductors, lithium-ion batteries, and organic electroluminescence devices. In the field, on-site calibration of a trace moisture analyzer is required to maintain its reliability. Given these circumstances, we previously developed a ball surface acoustic wave (SAW) sensor using SAW

Identifying abnormalities in red blood cells can provide important medical clues for the diagnosis, prognosis, and treatment of some health disorders. A common test used to examine the conditions of erythrocytes in humans is osmotic fragility. The standard technique to determine the osmotic fragility of red blood cells is laborious and time-consuming, and provides only approximate values with a few

We developed a flow visualization system based on laser Doppler velocimetry (LDV) to investigate the relationship between blood flow and blood coagulation in a blood chamber in an extracorporeal circulation circuit. Linear laser intersection was used to implement 32-point simultaneous measurement. The intersection region was traversed along the axial direction to obtain a two-dimensional (2D) velocity

Vehicle re-identification (Re-ID) has been attracting increasing interest in the field of computer vision due to the growing utilization of surveillance cameras in public security. However, vehicle Re-ID still suffers a similarity challenge, despite the efforts made to solve this problem. This challenge involves distinguishing different instances with nearly identical appearances. In this paper, a

Time-resolved Doppler global velocimetry (TRDGV) is used to demonstrate three-component velocity measurements of 32 planar points, acquired simultaneously at 250 kHz. Photomultiplier tube arrays are used to detect the flow signal, with each array having eight rows of four pixels. The system utilizes frequency scanning of a continuous wave laser, allowing for simple calibration of the signals used to