Simultaneous Measurement System Research Articles

Development of Simultaneous Dual-Resolution Digital Holography System

This research paper is focused on the development of a digital holography system for simultaneous dual-resolution measurements. Digital holography has been widely used for deformation measurements and non-destructive testing (NDT) due to its advantages of high sensitivity, high accuracy, and whole-field, non-touch measurements. A traditional test only has one spatial resolution, which can cause a big deformation to be indistinguishable or minor defects to be ignored. Both large and small fields of view should be observed to reach a multi-spatial resolution measurement. Usually, multiple separate tests are used to observe the different sized fields of view, resulting in higher costs and longer required testing times. Furthermore, these tests may not be repeatable in some cases. This paper presents research on a novel digital holography system that achieves dual spatial resolution measurements simultaneously by testing different-sized fields of view with a single camera. The novel system has two optical channels with two optical layouts of holography to measure deformation. By changing the combined focus length, the two holographic setups have different fields of view, i.e., one has a large and the other has a small field of view. To realize a simultaneous test, the polarization technique is used to avoid cross-interference between the two optical layouts. Finally, spatial carrier fringes with different orientations are introduced into the two holographic setups by appropriately adjusting the reference beam of each setup. The different oriented spatial carrier fringes enable the spectrums of the two interferograms to be separated after a FT (Fourier transform) and the phase distributions of the two interferograms can be extracted and separated by windowing the spectrum to perform an IFT (inverse Fourier transform). The phase distributions can then be used to analyze and calculate the deformations. The experiment using this system is described in this paper and the practicability of this method is verified by the obtained experimental results.

Photonics-Based Simultaneous DFS and AOA Measurement System without Direction Ambiguity

A novel scheme that can simultaneously measure the Doppler frequency shift (DFS) and angle of arrival (AOA) of microwave signals based on a single photonic system is proposed. At the signal receiving unit (SRU), two echo signals and the reference signal are modulated by a Sagnac loop structure and sent to the central station (CS) for processing. At the CS, two low-frequency electrical signals are generated after polarization control and photoelectric conversion. The DFS without direction ambiguity and wide AOA measurement can be real-time acquired by monitoring the frequency and power of the two low-frequency electrical signals. In the simulation, an unambiguous DFS measurement with errors of ±3 × 10-3 Hz and a -90° to 90° AOA measurement range with errors of less than ±0.5° are successfully realized simultaneously. It is compact and cost-effective, as well as has enhanced system stability and improved robustness for modern electronic warfare systems.

A Simple Photonic System for DFS and AOA Simultaneous Measurement

A simple photonics-based dual-channel system is proposed to simultaneously measure the Doppler frequency shift (DFS) and angle of arrival (AOA) of microwave signals. The system applies two parallel push–pull Mach–Zehnder modulators (MZMs) for carrier suppression dual-sideband (CS-DSB) modulation. The introduction of the reference signal results in a DFS measurement without direction ambiguity. The DFS can be determined by measuring the frequency of the down-converted intermediate frequency (IF) signal, and the AOA can be calculated by comparing the phase shift of the two channels. A proof-of-concept experiment shows that the DFS measurement error is less than 0.4 Hz during ±100 kHz, and the AOA measurement error is within 1.5° in a range of 0–70°.

Development of Time- and Energy-Resolved Synchrotron-Radiation-Based Mössbauer Spectroscopy

Synchrotron-radiation based Mössbauer spectroscopy has become a useful technique capable for investigating various Mössbauer isotopes. For a typical experimental setup, the information associated with the pulse height (that is, energy) in an avalanche photodiode (APD) detector has not been used effectively. By using a system for simultaneous measurement system of time and energy associated with the APD signal, a system for the time- and energy-resolved Mössbauer spectroscopy has been developed. In this system, the pulse height information was converted to the time information through an amplitude-to-time converter applied to one of the divided signals from the APD. The corresponding time information was processed separately from another one of the divided signals. Both signals are recorded by a multi-channel scaler in an event-by-event data acquisition process. The velocity information from the Mössbauer transducer was also recorded as a tag for each signal event. Thus, the Mössbauer spectra with any time- and energy-window can be reconstructed after the data collection process. This system can be used for many purposes in time- and energy-resolved Mössbauer spectroscopy, and shows significant promise for use with other fast detectors and for various types of experiments.

Development and performance evaluation of a mixed-sensor system for fine particles and road traffic noise

In recent years, the Internet of Things and low-cost sensor technologies have been applied to establish low-cost sensor networks for monitoring single pollutants in the environment. Few studies have developed a mixed-sensor system for simultaneous measurements of particles and noise, but the influences of meteorology and other pollutants are not taken into account. This study aimed to develop a mixed-sensor system for fine particles and noise with low-cost sensor technologies for considering effects of temperature, relative humidity, and carbon dioxide (CO 2 ). This mixed-sensor system was evaluated in the laboratory and field by using regular direct-reading instruments, including a portable dust monitor for fine particles and a class 1 sound level meter for noise measurements. Linear regression models were used to establish the relationships between measured values in the direct-reading instruments and sensor values. The present study established a predictive model of PM 2.5 concentration with a high predictive capacity (R 2 = 0 . 89 ) and good accuracy (bias and precision of 0 . 74 ± 1 . 67 μ g/m 3 ; accuracy of 1 . 82 μ g /m 3 based on relative humidity, CO 2 levels, and PM 2.5 sensor values). A predictive model of noise levels was built with a high predictive capacity (R 2 = 0 . 96 ) and moderate accuracy (bias and precision of 2.92 ± 2.96 dBA; accuracy of 4.16 dBA based on temperature, relative humidity, CO 2 levels, and noise sensor values). The developed predictive models with the high and moderate accuracy for a mixed-sensor system can be applied to monitor PM 2.5 and noise levels simultaneously for exposure assessment in exposure studies. • A mixed-sensor system was developed to monitor PM 2.5 and noise levels. • This low-cost system was validated in the laboratory and field. • Temperature, relative humidity, and CO 2 were considered in the predictive models. • The PM 2.5 model was developed with the high predictive capacity and good accuracy. • The noise model was built with a high predictive capacity and moderate accuracy.

Long-Range Wireless System for U-Value Assessment Using a Low-Cost Heat Flux Sensor.

The present study exposes an economical and easy-to-use system to assess the heat transfer in building envelopes by determining the U-value. Nowadays these systems require long wires and a host to collect and process the data. In this work, a multi-point system for simultaneous heat flux measurement has been proposed. The aim is to reduce the long measurement time and the cost of thermal isolation evaluations in large buildings. The system proposed consists of a low-cost 3D-printed heat flux sensor integrated with a LoRa transceiver and two temperature sensors. The heat flux (HF) sensor was compared and calibrated with a commercial HF sensor from the Fluxteq brand.

In situ simultaneous measurement system combining photoelastic, strain gauge measurement, and DIC methods for studying dynamic fracture

The photoelastic, digital image correlation (DIC), and strain gauge measurement methods are extensively used for studying dynamic fracture mechanics. However, few studies on dynamic fracture focus on combining these methods. In this study, a simultaneous measurement system for in situ investigation on dynamic fractures using the photoelastic, DIC, and strain gauge measurement methods was established for the first time. To reveal the performance of the system, impact experiments were conducted on three-point bending beam specimens fabricated using epoxy resin; consistent results were obtained from the three methods. The developed system provides rich experimental data, including full-field information of the stress, displacement, and strain fields.

Microwave-photonic interferometer based on FLRD for simultaneous sensing of loss and temperature

The optical carrier-based microwave interferometry (OCMI) system for simultaneous loss and temperature measurement is proposed and demonstrated experimentally, which is implemented with the fiber loop ringdown (FLRD). By multiplexing the phase spectra of low and high radio frequencies (RF), the independent sensing of loss and temperature is achieved. With the advantages of robustness and immunity to crosstalk, the sensitivity of transmittance and temperature are at −0.4942 rad and −14.05 kHz/°C. The stability and tunable sensitivity of the sensing system are investigated and demonstrated by the numerical analysis and experiments. The principle of phase-shift FLRD is ameliorated by numerical investigation, verified by the experiment results. The independent sensing of loss and temperature is achieved by recording the phase spectra of low and high radio frequencies (RF), where the insensitive points play a vital role and provide a potential approach for multiplexing.

Dynamic intelligent measurement of multiple chirped signals of different types based on the optical computing STFT and the YOLOv3 neural network.

We propose a simultaneous measurement system for multiple signals of different types which combines the optical computing short-time Fourier transform (STFT) and You Only Look Once (YOLOv3) neural network. Through the system, the analytical expressions of multiple broadband signals of different types can be obtained in real time with high-frequency resolution. Experimentally, the accuracy of the signal type in the detection results can almost reach 100%. Additionally, the parameter measurement errors for the bandwidth (BW), pulse width (PW), center frequency (CF), and time of arrival (TOA) of each linear frequency-modulated (LFM) or quadratic frequency-modulated (QFM) signal are within ±30 MHz, ±20 ns, ±15 MHz, and ±20 ns, respectively. The frequency resolution can reach 60 MHz. Factors affecting the performance of the measurement system, such as the quantity of the signal and the number of the category, are discussed.

Simultaneous Measurement of Microwave Doppler Frequency Shift and Angle of Arrival Based on a Silicon Integrated Chip

A system for simultaneous measurement of micro-wave Doppler frequency shift (DFS) and angle of arrival (AOA) is proposed based on a silicon integrated chip. In the chip, two dual-drive Mach–Zehnder modulators (DDMZMs) with a microring resonator (MRR) inserted between them are integrated. When an external laser is coupled into the chip, it is first modulated by two echo signals via the first DDMZM and then goes through the MRR to introduce an optical phase shift to one of the first-order sidebands that falls into the resonance of the MRR. After being remodulated by the transmitted signal at the other DDMZM, the lightwave is coupled out from the chip and separated into two channels by an optical coupler. In each channel, a bandpass filter (BPF) is employed to select the upper and lower sidebands. By measuring and comparing the powers, frequencies, and phases of the beat signals in the two channels, the DFS (without direction ambiguity) and AOA can be acquired. Based on the proposed method, DFS within ±100 kHz at 10, 15, and 20 GHz is successfully estimated with a maximum error of ±0.028 Hz, and AOA measurement from 0° to 75° with errors less than ±1.53° is also realized.

In Vitro Modelling for Bulging Sinus Effects of an Expanded Polytetrafluoroethylene Valved Conduit Based on High-Speed 3D Leaflet Evaluation.

The study aimed to develop a pulmonary circulatory system capable of high-speed 3D reconstruction of valve leaflets to elucidate the local hemodynamic characteristics in the valved conduits with bulging sinuses. Then a simultaneous measurement system for leaflet structure and pressure and flow characteristics was designed to obtain valve leaflet dynamic behaviour with different conduit structures. An image preprocessing method was established to obtain the three leaflets behaviour simultaneously for one sequence with two leaflets images from each pair of three high-speed cameras. Firstly, the multi-digital image correlation analyses were performed, and then the valve leaflet structure was measured under the static condition with fixed opening angles in the water-filled visualization chamber and the pulsatile flow tests simulating paediatric pulmonary flow conditions in the different types of conduit structures; with or without bulging sinuses. The results showed the maximum 3D reconstruction error to be around 0.06 mm. In the steady flow test, the evaluation of opening angles under the different flow rates conditions was achieved. In the pulsatile flow test, each leaflet's opening and closing behaviours were successfully reconstructed simultaneously at the high-frequency recording rate of 960fps. Therefore, the system developed in this study confirms the design evaluation method of an ePTFE valved conduit behaviour with leaflet structures interacting with local fluid dynamics in the vicinity of valves. Clinical Relevance- The system reveals the bulging sinus effects on ePTFE valve leaflet motion by the 3D reconstruction using multi-camera high-speed sequential imaging in vitro.

BIOSENSOR FOR ALT MEASUREMENT

In this work, an amperometric biosensor to determine ALT, which will be part of a biosensor system for simultaneous measurement of AST and ALT and their ratios, was developed. A platinum disk electrode was used as the electrochemical transducer. To form a bioselective element, a mixture based on glutamate oxidase was applied to the surface of transducer. A universal method for measuring ALT activity using the developed biosensor was proposed and described. During the study, the optimal concentrations of ALT substrates (α-ketoglutarate - 50 μM, alanine - 4 mM) and coenzyme (50 mkM of PLP) were selected. The analytical characteristics of the developed biosensor were also investigated, namely, sensitivity, linear range, minimum limit of determination, selectivity, stability, etc. It was shown the fundamental possibility of using this biosensor to measure the content of ALT in real samples.

Compound 48/80 increases bladder wall compliance independent of mast cells

Changes in wall compliance are seen in many bladder pathologies, such as fibrosis and diabetes. Some of these pathologies can be caused by basic secretagogues like Compound 48/80 and its endogenous analogue, Substance P. Traditionally it is believed that basic secretagogues rapidly degranulate mast cells and release inflammatory mediators by acting on an orphan receptor, Mas‐related G protein‐coupled receptor B2 (Mrgprb2). While Compound 48/80 does increase wall compliance, the exact location and function of Mrgprb2 in the urinary bladder are still unknown. We hypothesize that changes in bladder wall compliance caused by Compound 48/80 are mediated through Mrgprb2 receptors but independent of mast cell degranulation.Whole mouse bladders from C57Bl/6 (wild‐type) and C‐kitW‐sh (mast cell‐deficient) mice were dissected and mounted in a custom designed pentaplanar reflected image macroscopy (PRIM) system for simultaneous measurement of transient pressure events, intravesical pressure, bladder volume, wall stress, and wall stretch during ex vivo bladder filling. Wall compliance was derived as a measure of the stress versus stretch relationship using the pressure‐volume curves and associated imaging data. To test our hypothesis, bladders were exposed to either vehicle or Compound 48/80 (10 µg/ml) during ex vivo filling. Compound 48/80 significantly increased the leading slope of transient pressure events in both wild‐type and mast cell‐deficient mice. Compliance was also increased, as shown by decreased stress per change in stretch. We also collected urothelium and detrusor layers from C57Bl/6 and C‐kitW‐sh mouse bladders. Layers were separated using blunt dissection, and RNA was isolated for measurement of Mrgprb2 expression using qRT‐PCR. No significant difference in the expression of Mrgprb2 mRNA was observed between the two mouse models in either the urothelium or detrusor layers. These findings suggest that Mrgprb2 receptors are also expressed outside of mast cells in the urinary bladder wall and, when activated by Compound 48/80, increase wall compliance and the leading slope of transient pressure events.

Photonic System for Simultaneous and Unambiguous Measurement of Angle-of-Arrival and Doppler-Frequency-Shift

A photonic system based on a two-channel structure is proposed to realize the simultaneous measurement of angle-of-arrival (AOA) and Doppler-frequency-shift (DFS) of microwave signal without direction ambiguity. The unambiguous AOA measurement can be acquired by recording the power of the output intermediate frequency (IF) signal and output radio frequency (RF) signal from two channels. The DFS can be determined from the frequency of the IF signal. Estimated experimental results show that a −66.44° to 66.44° AOA measurement with errors of less than ±2.2° and an unambiguous DFS measurement with errors of ±0.6 Hz are implemented.

Vacuum Based Gas Sensing Material Characterization System for Precise and Simultaneous Measurement of Optical and Electrical Responses.

Gas sensing performance characterization systems are essential for the research and development of gas sensing materials and devices. Although existing systems are almost completely automatically operated, the accuracies of gas concentration control and of pressure control and the ability to simultaneously detect different sensor signals still require improvement. In this study, a high-precision gas sensing material characterization system is developed based on vacuum technology, with the objective of enabling the precise and simultaneous measurement of electrical responses. Because of the implementation of vacuum technology, the gas concentration control accuracy is improved more than 1600 times, whereas the pressure of the test ambient condition can be precisely adjusted between vacuum and 1.2 bar. The vacuum-assisted gas-exchanging mechanism also enables the sensor response time to be determined more accurately. The system is capable of performing sensitivity, selectivity, and stability tests and can control the ambient relative humidity in a precise manner. More importantly, the levels of performance of three different optical signal measurement set-ups were investigated and compared in terms of detection range, linearity, noise, and response time, based on which of their scopes of application were proposed. Finally, single-period and cyclical tests were performed to examine the ability of the system to detect optical and electrical responses simultaneously, both at a single wavelength and in a spectral region.

Dual stereo-digital image correlation system for simultaneous measurement of overlapped wings with a polarization RGB camera and fluorescent speckle patterns.

Simultaneous monitoring of overlapped multi-wing structure by stereo-digital image correlation (stereo-DIC) may be used to quantify insect motion and deformation. We propose a dual stereo-DIC system based on multispectral imaging with a polarization RGB camera. Different fluorescent speckle patterns were fabricated on wings, which emit red and blue spectra under ultraviolet light that were imaged and separated using a polarization RGB camera and auxiliary optical splitting components. The resulting dual stereo-DIC system was validated through translation experiments with transparent sheets and reconstructed overlapped insect wings (cicadas). Dynamic measurements of the Ruban artificial flier indicate the efficacy of this approach to determining real insect flight behavior.

Coaxial μSAXS/POM simultaneous measurement for microstructural characterization of one-dimensional and two-dimensional crystalline polymer

The microfocus beam small-angle X-ray scattering (μSAXS) provides a high spatial resolution ability, and the μSAXS/POM simultaneous measurement facilitates the acquisition of the micro-structural variations in the heterogeneous samples. Herein, at the SSRF BL19U2 beamline, a coaxial μSAXS/POM simultaneous measurement system has been established, comprising of the compound refractive lenses and an in-situ polarizing microscope. The SAXS beam size of 5.43 μm × 6.52 μm with a flux of 2.52 × 1011 photons/s has been employed. In order to obtain realistic microstructural information, the visible light path of the polarizing microscope has been set coaxially with the X-ray to eliminate the field of view deviation. The microstructure of the ringed spherulites of the polyoxymethylene/polybutylenesuccinate blends and high-density polyethene (HDPE) fibers has been simultaneously characterized. The differences in the structural information at different positions inside the banded spherulites have been evaluated. The crystallinity of the HDPE fibers increases from the skin to core, whereas the average crystalline lamellae thickness of the HDPE fibers decreases from skin to core, and the long spacing remains almost unchanged in the fibers.

Experimental investigation of the influence of floating ices constraint on the cavity dynamics of an axisymmetric body during the water exit process

The process of water exit in an ice-constrained environment involves complicated gas-liquid-solid multiphase turbulence flows. This paper considers the effects of the floating ices during the water exit process of a cone-shaped axisymmetric test body with an acceleration sensor and a pressure sensor. The cavity evolution, motion features and dynamics loads are addressed based on the simultaneous measurement system. The results show that the water exit process is divided into three stages, and the evolution patterns of the flow field and motion characteristics of the vehicle are closely related to the free water surface. The cavity evolution, movement characteristics and pressure loads during the water exit process of the vehicle are related to the existence of crushed ice. The existence of crushed ice has an effect on cavity dynamics. Especially, the blocking and restraining effects are mainly concentrated in the process of the vehicle crossing the free water surface.

Multi-Functional Microwave Photonic Radar System for Simultaneous Distance and Velocity Measurement and High-Resolution Microwave Imaging

A photonic-assisted multi-functional radar system for simultaneous distance and velocity measurement and high-resolution microwave imaging is proposed and experimentally demonstrated by using a composite transmitted microwave signal of a single-chirped linearly frequency-modulated (LFM) signal and a single-tone microwave signal. In the system, the transmitted signal is generated via photonic frequency up-conversion based on a single integrated dual-polarization dual-parallel Mach-Zehnder modulator (DPol-DPMZM), while the echo signals scattered from the target are de-chirped to two low-frequency signals using a microwave photonic frequency mixer. By using the two low-frequency de-chirped signals, the real-time distance and radial velocity of the moving target can be measured accurately according to the round-trip time of the echo signal and its Doppler frequency shift. Compared with the previously reported distance and velocity measurement methods, where two LFM signals with opposite chirps are used, these parameters can be obtained using only a single-chirped LFM signal and a single-tone microwave signal. Meanwhile, high-resolution inverse synthetic aperture radar (ISAR) imaging can also be realized using ISAR imaging algorithm. An experiment is performed to verify the proposed multi-functional microwave photonic radar system. An up-chirped LFM signal from 8.5 to 12.5 GHz and an 8.0 GHz single-tone microwave signal are used as the transmitted signal. The results show that the absolute measurement errors of distance and radial velocity are less than 5.9 cm and 2.8 cm/s, respectively. ISAR imaging results are also demonstrated, which proves the high-resolution and real-time ISAR imaging ability of the proposed system.

Rapid depolarization and cytosolic calcium increase go hand-in-hand in mesophyll cells' ozone response.

Plant stress signalling involves bursts of reactive oxygen species (ROS), which can be mimicked by the application of acute pulses of ozone. Such ozone-pulses inhibit photosynthesis and trigger stomatal closure in a few minutes, but the signalling that underlies these responses remains largely unknown. We measured changes in Arabidopsis thaliana gas exchange after treatment with acute pulses of ozone and set up a system for simultaneous measurement of membrane potential and cytosolic calcium with the fluorescent reporter R-GECO1. We show that within 1min, prior to stomatal closure, O3 triggered a drop in whole-plant CO2 uptake. Within this early phase, O3 pulses (200-1000ppb) elicited simultaneous membrane depolarization and cytosolic calcium increase, whereas these pulses had no long-term effect on either stomatal conductance or photosynthesis. In contrast, pulses of 5000ppb O3 induced cell death, systemic Ca2+ signals and an irreversible drop in stomatal conductance and photosynthetic capacity. We conclude that mesophyll cells respond to ozone in a few seconds by distinct pattern of plasma membrane depolarizations accompanied by an increase in the cytosolic calcium ion (Ca2+ ) level. These responses became systemic only at very high ozone concentrations. Thus, plants have rapid mechanism to sense and discriminate the strength of ozone signals.