首页期刊导航|Measurement
期刊信息/Journal information
Measurement
Elsevier BV
Measurement

Elsevier BV

0263-2241

Measurement/Journal MeasurementISTPSCIAHCI
正式出版
收录年代

    Improved feature extraction of guided wave signals for defect detection in welded thermoplastic composite joints

    Kubrusly A.C.Ferreira G.R.B.de Castro Ribeiro M.G.Ayala H.V.H....
    12页
    查看更多>>摘要：? 2022 Elsevier LtdMachine learning has shown to be a powerful diagnostic tool for interpreting guided wave signals towards modeling damage indexes. However, few works propose the use of machine learning techniques to build an automatic health diagnosis framework for composite welding. This work aims to devise an automatic diagnostic tool based on the propagation of ultrasonic guided waves for composite weld defect detection. Different feature extraction methods and machine learning modeling paradigms are investigated to highlight the most suitable strategy for performing the task. The support vector machine with autoregressive features resulted in the best overall performance. The accuracy was improved by 123.04% compared to other methods present in the literature, and satisfactory computational complexity was achieved. We have extended the previously reported results, showing that feature engineering enhances the model's effectiveness, making it possible to devise an automatic diagnosis framework that uses multi-frequency data and enables small data evaluation using resampling.
      原文链接:
    • NSTL
    • Elsevier

    Microwave traveling-standing wave method for density-independent detection of grain moisture content

    He X.Yu X.Song Q.Li C....
    8页
    查看更多>>摘要：? 2022 Elsevier LtdMoisture content is the major parameter that affects the quality of grain storage, transportation, and processing. Bulk density and multiple reflections of electromagnetic waves are the two main interference factors that affect the accuracy of the microwave method of grain moisture content detection. In this work, a free space traveling-standing wave method is proposed for eliminating interference. A microwave radar measurement system was developed for the rapid, non-destructive, and high-precision detection of grain moisture content. The moisture content density-independence equations are established based on the phase shift and attenuation of the traveling-standing wave node. For soybean and wheat, the determination coefficients of moisture content calibration equations are 0.995 and 0.975, respectively, and the standard errors of prediction are 0.564% and 0.983%. The system can complete the measurement in a few seconds, and the portable structure enables the device to be flexibly applied to the field of industry and agriculture.
      原文链接:
    • NSTL
    • Elsevier

    A load spectrum editing method of time-frequency for rubber isolators based on the continuous wavelet transform

    Liu X.Zhao X.Shangguan W.-B.Liu X.-A....
    13页
    查看更多>>摘要：? 2022 Elsevier LtdThe load spectrum editing method of rubber isolator under the criterion of real damage retention was studied. A time-frequency editing method based on the continuous Morlet wavelet transform (CMWT) was proposed. In this method, the accumulative power spectral density (APSD) of strain-load spectrum was obtained using the CMWT method. Then an APSD threshold was set and time segments with small damage contribution in the load spectrum were identified and removed to obtain the edited load spectrum. For comparisons, the conventional time-domain editing method was used to edit the load spectrum. The obtained results show that the time compression of the proposed method is larger than that of the other editing method. The original and edited load spectra are consistent in terms of statistical parameters. Moreover, based on the mount fatigue analysis, the edited load spectrum was verified to have the same loading effect as the original load spectrum.
      原文链接:
    • NSTL
    • Elsevier

    Optical measurement method of non-spherical particle size and concentration based on high-temperature melting technique

    Li Y.Wang X.Wu X.Lu L....
    9页
    查看更多>>摘要：? 2022 Elsevier LtdOptical particle counter (OPC) is always used to measure particles in high-temperature gas pipelines through gas cooling, leading to the original molten droplets condensing into irregular solid particles. To solve the problem, an optical measurement method of non-spherical particle size and concentration based on high-temperature melting technique is proposed. By establishing the theoretical dynamic model of optical measuring volume (OMV) of commercial OPC (Welas 3000, PALAS GMBH, Germany) with changing gas temperature and studying the thermal expansion characteristics of aerosol conduit, the influence of gas temperature on OPC optical sensor is analyzed, and OPC is applied at 650 °C. On this foundation, irregular glass particles are melted into spherical shape by high-temperature melting technique to realize the optical measurement of particle size and mass concentration. By comparing the online and off-line results of mass concentration, the deviation between them is less than 5%, verifying the feasibility of the proposed method.
      原文链接:
    • NSTL
    • Elsevier

    An improved total station measurement method for the georeferenced orientation of self-propelled artillery barrel

    Wang H.Han L.Du B.Shi Z....
    14页
    查看更多>>摘要：? 2022 Elsevier LtdSelf-propelled artillery is the main suppressing weapon installed by the armies of various countries, which plays an important role in modern warfare. With the continuous development of military science and technology, modern warfare has put forward higher requirements for the autonomous combat capability and precision strike capability of self-propelled artillery. Therefore, it is necessary to measure and verify the orientation of the self-propelled artillery barrel after maintenance and before firing. Among the various methods to achieve high-precision measurement of self-propelled artillery barrel orientation, the total station measurement method has shown good results in measurement accuracy, cost-effectiveness, and applicability to complex environments. However, there are some problems in the traditional total station measuring barrel orientation method, such as the lack of a north benchmark and the barrel calibration error. Therefore, this study aimed to develop an improved method for measuring the barrel orientation of self-propelled artillery, which solved the above problems by integrating the standard north orientation and the simulated axis of the barrel using a total station. First, to establish the measurement coordinate system of the measurement area, the standard north orientation of the measurement field area is determined using a positioning orientation instrument based on the Radio Navigation Satellite System. Second, to complete the barrel calibration, two magnetic target plates are set on the barrel, and a fixed spatial positional relationship between the connection line of the magnetic target center points and the barrel axis is established. Third, the barrel of self-propelled artillery is adjusted to the measurement attitude, and the magnetic target is observed and sighted with a total station to obtain its spatial coordinates in the measurement coordinate system. Subsequently, the error analysis of the measurement plan was carried out, and it was found that the position of the total station had a great influence on the measurement accuracy of the barrel orientation. Therefore, the uncertainty model of the measurement accuracy about the location of the station is established, and the station deployment area is scanned based on the idea of the Monte Carlo method to find the optimal measurement area. Finally, a certain type of self-propelled artillery is used to carry out an installation experiment. The experiment shows that the improved method solves the problems of the traditional method which lacks a north benchmark and the barrel calibration error, and can ensure that the measurement error is within 0.2mil, which assists in the development of precision self-propelled artillery strikes.
      原文链接:
    • NSTL
    • Elsevier

    Characterisation of needle edge quality using diffraction pattern

    Rani M.Mishra V.Singh O.Kumar R....
    11页
    查看更多>>摘要：? 2022The performance of hypodermic needles is mainly dependent on quality of their edges. The quality of the needle edges directly impacts penetration forces, tissue healing time, and patient pain. At present, only subjective techniques are used to access quality of edges of the needles which are not capable to contribute during manufacturing. Thus an appropriate technique is desirable to characterize the defects of the needle edges. This study aims to develop a characterization technique for measurement of defects such as roughness, chips and tip bending on the edges of needles. The proposed technique uses the diffraction fringes, obtained from the superposition of diffracted light from needle edges and the direct propagated light from the source. Variations in the fringes and their intensity profiles are utilized to study the defects. Further, the results are compared with results obtained from a standard optical profiler and a microscope. The standard deviation of proposed technique for repeatability and reproducibility of measurements are σ = 0. 104 a.u and σ = 0. 87 a.u, respectively. This technique is simple, non-contact in nature, uses compact configuration and is capable for qualitative and quantitative evaluation of the hypodermic needles.
      原文链接:
    • NSTL
    • Elsevier

    Soft fault diagnosis in wiring networks using reflectometry and Principal Component Analysis

    Taki N.Ben Hassen W.Ravot N.Delpha C....
    17页
    查看更多>>摘要：? 2022 Elsevier LtdDuring operation, cables may be subject to hard faults (open circuit, short circuit) or soft faults (isolation damage, pinching, etc.) due to misuse, environmental conditions, or aging. Even though several electric and non-electric wire diagnosis methods have been studied and developed throughout the last few decades, reflectometry-based techniques have provided effective results with hard faults. However, they have shown to be less effective for soft faults. Indeed, soft faults are characterized by a small impedance variation, resulting in a low amplitude signature in the reflectograms. Accordingly, the detection of these faults depends strongly on the test signal bandwidth. Although the increase of the maximal frequency of the test signal enhances the soft fault's ”spatial” resolution, the performance is limited by signal attenuation and dispersion. This study proposes a method to select the best maximal frequency for soft fault detection. It is based on a combination of reflectometry with Principal Component Analysis (PCA), and the analysis of the Squared Prediction Error (SPE). Experimental validation is carried out, and performance analysis in the presence of noise is investigated. The results for shielding damage show that when the soft fault is near the injection point, the detection probability equals to one even for SNR values as low as 0 dB. As the fault position approaches the end of the cable, the performance is still acceptable, but for lower fault severities, the detection is almost impossible. The results also show that the selected frequency depends on the fault severity, the fault position, and the noise level.
      原文链接:
    • NSTL
    • Elsevier

    Investigating the interactions of hydrogen and nitrogen with the tantalum cathode of a novel ionization vacuum gauge with a straight path of electrons

    Janez SetinaTim Verbovsek
    6页
    查看更多>>摘要：The outgassing characteristics of a tantalum disk cathode mounted inside a novel ionization gauge were investigated in comparison to an yttrium-coated iridium-filament cathode mounted inside an extractor gauge. Both gauges were exposed to nitrogen or hydrogen at a pressure of 2.4 × 10~(-5) mbar, and the outgassing rates were measured periodically during subsequent pumping. For the novel ionization gauge, two contributions to the outgassing, i.e., the thermal outgassing from the cathode and the electron-stimulated desorption from the Faraday cup, were studied separately. The tantalum cathode showed rapid outgassing of nitrogen after exposure, while the outgassing after exposure to hydrogen was much lower. Hydrogen is mainly released from the Faraday cup when electrons collide with it. The extractor gauge showed a more-than-3-times higher outgassing rate after hydrogen exposure than after nitrogen exposure. The tantalum cathode and the Faraday cup in the novel ionization gauge showed absorption equilibrium after just 30 min.
      原文链接:
    • NSTL
    • Elsevier

    Shear deformation characteristics of a flexible casing in gob gas ventholes: Experimental and numerical investigation

    Jiang M.Liu Y.Kang J.Long Z....
    11页
    查看更多>>摘要：? 2022 Elsevier LtdGas drainage is valuable for gas-outburst disaster prevention and gas resource utilization. The application of gob gas ventholes (GGVs) is an effective method for gas drainage in the gas-bearing coal seam. The measurement of the deformation in GGVs is critical. Compared with a rigid casing, a flexible casing has better anti-deformation performance to protect the original structure. To understand the deformation advantages involved in this casing, we performed experiments and simulations to study casing deformation characteristics under shear displacement. The results showed that flexible casings are commonly characterizes by significant structural integrity. Tensile deformation occurred on both the upper and the lower inner torus of the centre corrugation, producing a stronger local deformation ability. Moreover, the deformation coefficient of the flexible casing was defined to describe the influence on the flow capacity. This study was beneficial for the further optimization and utilization of flexible casings in GGVs for gas drainage.
      原文链接:
    • NSTL
    • Elsevier

    Cyclic correlation density decomposition based on a sparse and low-rank model for weak fault feature extraction of rolling bearings

    Wang R.Yu L.Fang H.Chen J....
    17页
    查看更多>>摘要：? 2022 Elsevier LtdThe weak fault feature extraction of rolling element bearings is of critical interest for fault diagnosis. The initial fault is always very weak and buried in high background noise, making it extremely hard to extract the fault feature. Thus, it is essential to correctly extract the weak fault feature of the rolling bearings. A weak fault feature extraction approach using Cyclic correlation density decomposition based on the sparse and low-rank model is proposed in this article. According to the cyclic statistical properties of the fault-bearing signal, the Fast Spectral Correlation (Fast-SC) algorithm is employed to obtain the Cyclic Spectral Density (CSD). It is founded that the CSD of periodic impulse exhibits a high degree of sparsity. Then, the sparsity is exploited into the sparse and low-rank decomposition model to extract the fault features. The CSD is decomposed into two components with the Robust Principal Component Analysis (RPCA) algorithm. The sparse component corresponds to the periodic fault impulse, while the low-rank component represents interference. It is noteworthy that the decomposed sparse component exhibits high resolution and high sparsity, which means the bearing fault features can be revealed clearly and accurately. Finally, the rolling bearing fault feature is detected effectively by the Enhanced Envelope Spectrum (EES). Both simulation fault signal and experimental data are analyzed to verify the proposed method's performance. A Frequency Component Indicator (FCI) and a Relative Indicator Gain (RIG) are constructed to quantify the comparison of the extraction results. The RIG of the proposed method relative to the envelope spectrum is more than 10 dB in the simulated bearing signal with a low SNR of-10 dB, and more than 6 dB in the experimental case. These results validate that the proposed method can extract weak fault features more effectively than some existing methods.
      原文链接:
    • NSTL
    • Elsevier