On-line Measurement System Research Articles

Non-destructive prediction of soluble solid contents in Fuji apples using visible near-infrared spectroscopy and various statistical methods

The increasing awareness regarding dietary diversity and pattern has increased the demand for quality over quantity. Numerous non-destructive measurements, including visible near-infrared spectroscopy, have been used in assessing the soluble solid content (SSC) in foods. With advances in statistics, various statistical methods have been developed. These methods need to be verified for their application in effective SSC prediction models. This study aims to review the utility of various statistical methods for the SSC prediction of apples. In this study, we constructed a sorting device for Fuji apples. The spectra of the apples were measured, and the potential of the SSC prediction model was evaluated using various pre-processing methods and machine learning techniques. A developed support vector regression model with a first-order derivative method exhibited the highest prediction accuracy (R 2 = 0.8503, RMSEP = 0.4781). Therefore, the developed efficient spectrum pre-processing method coupled with a robust machine learning model was useful for improving the prediction performance of the sorting device. • Spectra of apples and SSC values were measured. • Spectra were acquired using online measurement system functioning like actual sorting condition. • Various preprocessing methods and machine learning techniques were used. • Spectrum preprocessing with robust statistical regression model improves SSC prediction.

非接触施肥流量实时监测系统的设计与试验

Precision fertilization is one of the important links in the precision agricultural operation system. In recent years, the demand for precision fertilization in facility greenhouse has become more and more urgent. As such, this paper designs an accurate and practical fertilization on-line monitoring system. The system adopts capacitance conversion chip PCAP01 and SCM STM32F103C8T6 to build a capacitance detection circuit. The effective acquisition of differential capacitance sensor microcapacitor signal output under this system is realized. The response relationship between the mass flow and the sensor capacitance output was studied, and a linear fitting model of fertilization was established. According to the prediction, the model determination coefficient was 0.9997. The experiment shows that the system has good adaptability to ambient temperature. The average measurement error is 1.13%, which meets the technical requirements of flow measurement. The capacitive fertilization online measurement system provides an effective way for the on-line acquisition of fertilization flow. It is of great significance for the implementation of high-precision variable fertilization.

Study on operation voltage monitoring and electrothermal coupling simulation of electric multiple unit (EMU) roof arrester

The roof arrester of electric multiple units (EMU) can efficiently limit the overvoltage, and ensure the safe operation of the EMU electrical equipment. In the process of high-speed operation, the traction power supply system is often affected by overvoltage. In addition, roof arrester explosion accidents occasionally occur. In this paper, the on-line voltage measurement system of the EMU arrester is developed. By analysing a large number of voltage waveforms, the abnormal voltage is divided into three categories: over-phase voltage, high harmonic voltage and steep impulse overvoltage. The characteristics of abnormal voltage waveforms are then summarised. The electrothermal coupling simulation model of the arrester is developed, and the current response and temperature distribution of the arrester under abnormal voltage are calculated. The impact of the impulse voltage energy on the arrester temperature is studied by applying a triangular wave voltage to the model. Finally, some suggestions are proposed for the operation and maintenance of the roof arrester.

Optical coherence tomography for laser welding applications

In order to realize the automatic quality measurement of laser welding parts, an automatic on-line quality measurement system is established. The optical coherence tomography algorithm used in the system is studied. Firstly, the test equipment of laser welding quality inspection system is built based on optical coherence tomography algorithm. Then, the typical control algorithm is analyzed by taking the scanning galvanometer control as an example, that is, high-precision scanning and high-precision image acquisition in X and Y directions are realized. Then, the image is processed by dual-tree complex wavelet transform. Finally, the test sample is tested with the test equipment and the test results are analyzed. Experimental results show that this method can detect the quality of laser welding seam, and the detection accuracy is 5 µm. It provides industrial solutions for the online inspection of the laser welding to enable consistent and high quality welds.

IoT Online Monitoring System on Pulp and Paper Industry Wastewater Treatment Plant

As one of the largest wastewater producers in the world, the pulp and paper industry need to monitor the waste that they generated. To carry out this monitoring process, the majority of the pulp and paper industry still uses conventional offline methods to measure parameters in their wastewater treatment plants. The monitoring procedure is carried out by taking samples from the factory wastewater treatment plant and testing these samples in the laboratory. This procedure is very prone to errors caused by human. This method also cannot detect any violation, problem, or disturbance of the wastewater parameters in real time. In addition, in 2018, the Indonesian Ministry of Environment and Forestry issued a regulation requiring the pulp and paper industry to use a real-time online monitoring system for its wastewater treatment plant.
 This paper presents an implementation of the system. There are several parameters that must be measured, two of them are pH and TSS (Total Suspended Solids). To measure these parameters, the regulation states that the online measurement system is carried out using the relevant electric probe sensor. Then the measurement results are displayed online on a specified platform hence that users can observe the results. This implementation uses a pH sensor to measure pH and a conductivity sensor to measure TSS. A conductivity sensor is used as a substitute due to the high cost of TSS sensor. This article analyses also the accuracy of the measurement.

Online Measurement System for Dynamic Flow Bioreactors to Study Barrier Integrity of hiPSC-Based Blood–Brain Barrier In Vitro Models

Electrochemical impedance spectroscopy (EIS) is a noninvasive, reliable, and efficient method to analyze the barrier integrity of in vitro tissue models. This well-established tool is used most widely to quantify the transendothelial/epithelial resistance (TEER) of Transwell-based models cultured under static conditions. However, dynamic culture in bioreactors can achieve advanced cell culture conditions that mimic a more tissue-specific environment and stimulation. This requires the development of culture systems that also allow for the assessment of barrier integrity under dynamic conditions. Here, we present a bioreactor system that is capable of the automated, continuous, and non-invasive online monitoring of cellular barrier integrity during dynamic culture. Polydimethylsiloxane (PDMS) casting and 3D printing were used for the fabrication of the bioreactors. Additionally, attachable electrodes based on titanium nitride (TiN)-coated steel tubes were developed to perform EIS measurements. In order to test the monitored bioreactor system, blood–brain barrier (BBB) in vitro models derived from human-induced pluripotent stem cells (hiPSC) were cultured for up to 7 days. We applied equivalent electrical circuit fitting to quantify the electrical parameters of the cell layer and observed that TEER gradually decreased over time from 2513 Ω·cm2 to 285 Ω·cm2, as also specified in the static control culture. Our versatile system offers the possibility to be used for various dynamic tissue cultures that require a non-invasive monitoring system for barrier integrity.

Nondestructive Quantitative Analysis of Water Potential of Tomato Leaves Using Online Hyperspectral Imaging System

HighlightsWe developed an online measurement system for water potential of tomato plants using hyperspectral imaging.We used Linear Discriminant Analysis to automatically and quickly extract the leaf images.We used SNV scattering correction to remove the spectral variations caused by collecting the defocused leaf images.We developed a prediction model of leaf water potential based on spectral image information.Abstract. Tomatoes have different water requirements in each growing period. Excessive water use or insufficient water supply will affect the growth and yield of tomato plants. Therefore, precise irrigation control is necessary during cultivation to increase crop productivity. Traditionally, the soil moisture content or leaf water potential has been used as an indicator of plant water status. These methods, however, have limited accuracy and are time-consuming, making it difficult to be put into practice in tomato production. This study developed an online hyperspectral imaging system to measure the leaf water potential of tomato nondestructively. Linear Discriminant Analysis was utilized to automatically and quickly extract the leaf images, with the recognition accuracy of 94.68% was achieved. The mathematical processing of Standard Normal Variate scattering correction was used to remove the spectral variations caused by the defocused leave images. The developed leaf water potential prediction model based on the spectral image information attained using the developed system achieved the standard error of calibration of 0.201, coefficient of determination in calibration set of 0.814 and standard error of cross-validation of 0.230, and one minus the variance ratio of 0.755. The obtained performance indicated the feasibility of applying the developed online hyperspectral imaging system as a real-time non-destructive measurement technique for the leaf water potential of tomato plants. Keywords: Hyperspectral imaging system, Machine learning, Tomato, Water potential.

Research on High Precision Rapid Online Measurement System of Crankshaft Based on Multi-station

According to the structural characteristics and production requirements of the crankshaft, the online measurement platform of crankshaft was built. The multi-station assembly line is developed to measure, to mark and to classify the parameters and measurement elements of the crankshaft. In addition, SPC software is designed to perform mathematical statistics and analysis on the measurement information. It can distinguish between normal fluctuations and abnormal fluctuations in the production process, can inform the fluctuation state to determine whether it should be adjusted, can compare the fluctuations and provide direction for improvement. Finally, through multiple measurement experiments, the feasibility and effectiveness of the synchronous measurement scheme and data processing method proposed in this paper are verified. The experimental results show that GR&R is less than 9.3%, and measurement accuracy is less than or equal to 1μm.

Quantifying the CaO and CaF2 Content of Industrial Ladle Furnace Slag with Optical Emissions Measured through the Casting Spout

CaO and CaF2 are important slag constituents and additive materials in secondary metallurgy. Optimization of the quantity of these compounds has a key role in adjusting the slag chemistry for optimal refining properties. Herein, the CaO and CaF2 content of the slag is analyzed with optical emissions from an industrial ladle furnace measured through the casting spout. Molecular optical emissions from CaO and CaF are observed directly from the molten bath and the arc, whereas atomic emission lines from the slag components are detected in the arc spectra. Optical emissions from CaO, CaF, and atomic calcium lines are correlated with the CaO and CaF2 content of the slag. The CaO and CaF2 content of the slag could be evaluated from the spectra ranging from 10 to 41 min before the X‐ray fluorescence (XRF) analysis is finished. The mean differences between the optical emission spectroscopy (OES) and XRF analysis are 0.59% and 0.61% for CaF2 and 2.19% and 0.67% for CaO when using the spectra from the molten bath and the arc, respectively. The method has the potential to work as an in situ online measurement system due to real‐time data acquisition and fast computation times.

Research on Temperature Compensation Method in Crankshaft Online Measurement System

The crankshaft online measurement system has realized the full inspection function with fast beats, at the same time it requires for high-precision measurement. Considering the effect of ambient temperature and temperature changes on measuring machine, the calibration part, the measured crankshaft and displacement sensor, a temperature compensation method is proposed. Firstly, relationship between calibration part and ambient temperature can be get through the zero calibration. Then use the material properties to obtain compensation values of the calibration part and the measured crankshaft part at different temperatures. Finally, the compensation parameters for displacement sensor can be obtained through the BP algorithm. The improved dragonfly algorithm (DA) is used to optimize the parameters of BP neural network algorithm. Experiments verify the effectiveness of IDA-BP for LVDT in temperature compensation. After temperature compensation, the error range of main journal radius is reduced from 0.0156 mm to 0.0028 mm, the residual error decreased from −0.0282 mm~+0.0018 mm to −0.0058 mm~−0.0008 mm. The influence of temperature changes on the measurement is reduced and measurement accuracy is improved through the temperature compensation method. The effectiveness of the method is proved.

Reconstruction of three-dimensional temperature fields in micro-fixed bed reactor based on infrared thermography and thermal probe method

Aiming at determining the characteristics of small volume and complex heat and mass transfer of micro-reactors, an online measurement system was designed and built. The temperature of the reactor surface was measured by infrared thermography. For reconstruction of the three-dimensional temperature field of the micro-fixed bed reactor, mathematical and physical models were established by finite difference of governing equations and boundary conditions, and the objective function was established based on the principle of least squares. Then, using the conjugate gradient algorithm, the three-dimensional temperature field was rebuilt in the fixed bed reactor. It was verified that the micro-reactor filled with resin particles had a porosity of 0.432 under an initial temperature of 20 °C and adiabatic conditions; distilled water of a constant temperature of 50 °C was introduced into the reactor at a flow rate of 3.2 ml/min, and the internal temperature field was deduced from the surface temperature of the reactor. The experiment also used micro-thermocouples to measure the internal temperature at multiple points to compare with the inverse temperature field. The temperature change trend was consistent, and the maximum error was 4.85% in a no reaction condition and 7.1% in catalytic reactions, which verified the accuracy of the inverse method.

Study on the intrinsic detection efficiency of scintillator/Cherenkov detector for monitoring 14MeV neutrons by using foil activation method

A neutron detector, based on scintillator and Cherenkov detector, was designed to monitor the D-T neutron generator in a PGNAA online measurement system in our previous study. In this paper, the foil activation method was used to study the intrinsic detection efficiency of the detector to the D-T neutron generator. The Fe foil with 99.99% purity was selected as the activation foil. The experiments and the GEANT4 simulations were carried out to study the intrinsic detection efficiency of the monitor. The results show that the intrinsic detection efficiency of the monitor is 20.42% ± 0.76%. Then, the calibrated detector and Fe foils were simultaneously used to measure the neutron flux of D-T neutron generator. The relative deviation between the results of the two methods is 5.64%.

Development of measurement system using online software for shear-horizontal surface acoustic wave sensor

In the medical field, point-of-care testing (POCT) is garnering attention. An online inspection system can be realized by combining POCT and the Internet. Herein, we report the performances of a measurement system developed using online software for a shear horizontal surface acoustic wave (SH-SAW) sensor. The developed SH-SAW measurement system does not require a phase detection circuit. The developed system can be used when the system is connected to the Internet. This enables an online measurement system that can be used “by anyone, at anytime, and anywhere.” In this study, we used samples of glycerol and water mixtures and then measured the amplitude ratio and phase difference of the SH-SAW sensor. The validity of the developed system is confirmed by comparing the measured results with theoretical values.

Development of on-line lateral stiffness measurement system for anterior cruciate ligament and its influence on anterior cruciate ligament reconstruction

The anterior cruciate ligament (ACL) reconstruction mostly relies on the experience of surgeons. To improve the effectiveness and adaptability of the tension after ACL reconstruction in knee joint rehabilitation, this paper establishes a lateral force measurement model with relaxation characteristics and designs an on-line stiffness measurement system of ACL. In this paper, we selected 20 sheep knee joints as experimental material for the knee joint stability test before the ACL reconstruction operation, which were divided into two groups for a comparative test of single-bundle ACL reconstruction through the anterolateral approach. The first group of surgeons carried out intraoperative detection with routine procedures. The second group used ACL on-line stiffness measurement system for intraoperative detection. After that, the above two groups were tested for postoperative stability. The study results show that the tension accuracy is (- 2.3 ± 0.04)%, and the displacement error is (1.5 ± 1.8)%. The forward stability, internal rotation stability, and external rotation stability of the two groups were better than those before operation ( P < 0.05). But the data of the group using the system were closer to the preoperative knee joint measurement index, and there was no significant difference between them ( P > 0.05). The system established in this paper is expected to help clinicians judge the ACL reconstruction tension in the operation process and effectively improve the surgical effect.

Machining of cylindrical parts by wire electrical discharge grinding using thin plate guide

In order to meet the processing requirements of precise cylindrical parts on hard and difficult-to-machine materials, this paper introduces wire electrical discharge grinding (WEDG) using thin plate wire guide for cylindrical parts machining. The spindle system and the wire transport system to realize this processing method was added to a low speed wire electrical discharge machining (LS-WEDM) machine tool. In order to realize the online measurement of the machining accuracy of the cylindrical parts, an online measurement system of two-degree-of-freedom based on laser displacement sensor was built. The reasons for the incomplete removal of the machined surface were analyzed. Through the application of a new tool setting strategy and reasonable selection of processing parameters, the phenomenon of incomplete processing can be avoided. The experimental research on the effects of part rotational speed, wire feed rate, wire running speed and wire tension on roundness, surface roughness Sa, and surface morphology were carried out. Finally, example of the cylindrical parts is given to verify the machining accuracy.

Experimental study on on-line monitoring pulverized coal fineness of 300 MW coal-fired plant by digital holography

Pulverized coal fineness is one of the key parameters in the operation of coal-fired power plant, which is closely related to the combustion efficiency of boiler, power consumption of pulverizing system and equipment wear. In this paper, an experimental study on on-line monitoring of pulverized coal fineness by digital holography was carried out. An on-line measurement system based on pulse digital in-line holography was established. The system included four main parts: sampling, measuring, collecting and data processing. The measurement system was applied to the pulverized coal fineness monitoring in two primary air pipes of a 300 MW unit. The pulverized coal flow in the two pipes were from two different mills. The self-developed reconstruction software was used to process the holograms in real time and output the fineness results. The pulverized coal samples collected by the system were sieved in the laboratory, and the sieving results were compared with the holographic results to verify the feasibility and accuracy of the measurement system. Results show that the holographic results of area distribution are basically consistent with the sieving results, and the average absolute deviation is less than 4%. The test also diagnose that the coal fineness of one mill deviates greatly from the designed value, proving that the measurement system has great application potential for on-line monitoring of pulverized coal fineness in coal-fired power plants.

Development of a Monitoring System for Semicontinuous Measurements of Stable Carbon Isotope Ratios in Atmospheric Carbonaceous Aerosols: Optimized Methods and Application to Field Measurements.

Carbon content constitutes a major fraction of atmospheric particulate matter (PM) and directly influences the earth's climate and human health. The stable carbon isotope ratios (δ13C) can be used to track potential sources and atmospheric processes of carbonaceous aerosols. Previously, determination of δ13C was always conducted in offline carbonaceous aerosol samples. The poor time-resolution results cannot provide information regarding the temporal evolution of δ13C at a short-time scale. In this study, we developed a new system for online measurements of δ13C in atmospheric carbonaceous aerosols by combining a semicontinuous organic carbon/elemental carbon (OC/EC) analyzer and online cavity ring-down spectroscopy (CRDS) (OC/EC analyzer-CRDS). To provide better stability in the determination of δ13C, a carrier gas with CO2 (∼200 ppm) in "balance gas" was used, and Keeling analysis was employed to separate the δ13C signal of the sample from background CO2 gas. Our results showed that the accuracy and absolute precision of the δ13C measurements by the OC/EC analyzer-CRDS system were better than 0.1‰ and 0.5‰, respectively, for the samples containing carbon content more than 5 μg. Furthermore, we employed this system to monitor δ13C (δ13C-TC) in particulate total carbon (TC) with a time resolution of 2-4 h over Beijing in late summer and early autumn, 2019. During the sampling period, the TC concentrations varied from 0.1 to 12.0 μg m-3 with a mean value of 6.0 ± 2.4 μg m-3. The δ13C-TC ranged from -28.2 to -24.2‰ (mean value was -25.9 ± 0.9‰) without significant diurnal variations, suggesting similar contributing sources to TC. Comparing the δ13C signatures of different emissions, we found that liquid fuels and primary and secondary C3 plants were likely the dominant sources of particulate TC. Finally, we found that atmospheric heavy precipitation washed out the aged aerosols from the polluted air, resulting in significant depletion (∼2.4‰) of δ13C-TC in the atmosphere. This paper described a novel system for conducting online measurements of δ13C in atmospheric carbonaceous aerosols and provided us information to better understand the temporal evolution of emission sources and atmospheric processes of carbonaceous aerosols.

Development and application of online load measurement system for hanger and support

It was difficult to monitor the load and evaluate the performance of the hanger and support of power plant. The online load measurement system for hanger and support was developed and some experiments had been carried out. Compared with the offline bench performance testing machine, the experimental results showed that the average measurement error of the online measurement system was less than 1%. It can effectively measure the performance parameters of the hanger, conveniently and reliably monitor the real-time load of the hanger, which is important for the safe operation of the hanger and the steam/water pipeline in the power plant.

Real-time measurement method of melt pool temperature in the directed energy deposition process

In metal additive manufacturing, the quality of the parts is closely related to the temperature distribution in the melt pool; hence, real-time monitoring of the temperature distribution has become a common method of evaluating printing quality. However, there are difficulties in the temperature measurement of a melt pool related to its small size, high temperature, and rapid melting and cooling. A high-speed measuring optical path for a temperature field using a single camera is designed based on dual-wavelength thermometry herein. A dual-waveband image-matching method with sub-pixel accuracy, and a multi-parameter cooperative optimization and calibration method of proportional coefficient K, λ1, and λ2 are developed. Moreover, it was found that the splitting ratio of a beam splitter is not a constant value, rather, it is a distribution; hence, an accurate calibration method for the splitting ratio distribution of the optical system is developed. An on-line temperature measurement system is developed, and its validation experiment indicates a measuring error of less than 1%. The temperature distribution of the melt pool in the directed energy deposition (DED) process was measured. It was found that the temperature distribution was uneven, and the position of the high-temperature peak region changed with time. The evolution law of profile size and temperature change rates during the formation, development, and cooling process of the melt pool are analyzed. The method developed herein significantly reduces the system development cost, and can realize real-time monitoring of the temperature distribution of the melt pool in DED processing.

Study on control scheme of on-line measurement system for key dimension of spinning head

According to the basic principles of roller measurement and displacement measurement, the on-line measurement system of the outer circumference and roundness tolerance and its control scheme are discussed. To implement automatic and real time measurement of circumference and roundness tolerance, the S7-200 PLC is selected as the controller, the STEP7-Microwin V4.0 is used for programming, the ladder diagram is used as the programming language. The motion simulation test of the measurement system is carried out, and the results show that the control scheme is feasible.