查看更多>>摘要：? 2022 Elsevier LtdThe interconnected modern smart grid has resulted in several new power quality (PQ) disturbances that affect the frequency stability requirements in industrial power systems. Ranging between 50±0.1 Hz for interconnected networks, and even within the European synchronous area, the frequency fluctuates mainly because of the primary control. In fact, owing to the development of distributed resources (e.g. renewable energies), not all generation units are accessible, and are controllable in a few network nodes. This variability, even between nearby locations, triggers the need for a specific measurement strategies, based on an absolute reference and also conceived for monitoring PQ disturbances. This work proposes an easy-to-implement GPS-traceable method that allows the measurement of frequency with better accuracy than that required by the current regulation for interconnected networks. This work explains the measurement methodology, characterising the uncertainty by using ISO JCGM 100. For the purpose of testing and validation, three experiments were conducted: computer-designed, instrument-triggered lab disturbances, and a comparison vs. PMU performance, using real-life signals. The results showed that these experiments offered better performance with improved uncertainty.
查看更多>>摘要：? 2022A self-destruction module for information storage equipment (ISE) that releases a detonation wave via energetic materials (EMs) is discussed. The module uses an energy-grooming actuator (EGA) to isolate EMs from external electronic systems to improve security. The response time of removing electrical constraint for EMs, the stress transferring of detonation wave in air domain and the response time of ISE physical self-destruction are obtained via COMSOL, LS-DYNA, the module function integration is realized by stacked graphene and platinum films and in-situ copper azide synthesis. During tests, the response time of removing electrical constraint for EMs by EGA was 0.942 ms. When a voltage pulse (below 5.5 V) exploded the EMs, the detonation wave was generated under 61.8–63.2 μs to destroy the ISE. Overall, ISE physical self-destruction was realized with a lower driving energy, a fast response time and security control for the EMs. The module has potential applications for information security.
查看更多>>摘要：? 2022 The Author(s)The paper presents a novel measurement technique for non-contact properties change monitoring and material characterization which is suitable for in-progress monitoring of processes, especially ones using corrosive reagents or reactive materials. The method relies on sensing of dielectric properties of liquids contained inside a test tube at microwave frequencies by a quasi-parallel-plate transmission line type sensor. The theoretical study is validated with experimental data in terms of extracting complex effective permittivity and response reproducibility on an example of various alcohols. This is followed by measurements of ethanol-water and water-sodium persulfate solutions. The determined concentration-normalized differential reflection coefficient transfer curves for a discrete set of frequencies up to 2 GHz indicated sensitivity up to 14 dB/ml and ?172 °/ml with a resolution in the range of 6–7 μl for the former solution and up to ?17 dB/g and ?31 °/g. The obtained results prove the usability of the developed method.
查看更多>>摘要：? 2022 Elsevier LtdOff-axis digital holographic microscopy is widely used to avoid the twin image problem in the hologram, which provides the advantages of extracting the real image. However, the off-axis optical setup and the microscope objective will bring tilt and spherical phase aberrations to the digital reconstruction process. Therefore, it is urgent to explore efficient techniques innovatively to compensate for these aberrations. This study proposes a numerical method via a patch-based inpainting algorithm to eliminate these aberrations. This method can reconstruct the actual object phase from a hologram without polynomial fitting. The reconstruction results in both the experiment and simulation are analyzed and compared, confirming that the proposed method has good robustness and accuracy in phase retrieval.
查看更多>>摘要：? 2022 Elsevier LtdThis paper introduces a reliable approach based on start-up transient analysis using inverse thresholding to spectrogram for early detection of a broken rotor bar fault in an induction motor. The investigation has been done in the time–frequency plane since it is based on the non-stationarity assessment of fault frequencies. Typically, time–frequency analysis is carried out in the presence of the fundamental, resulting in the fault features appearing unnoticed. The proposed technique addresses this issue by weakening the fundamental, making fault features more clearly apparent. To achieve this, inverse thresholding to spectrogram has been utilized for motor start-up current. In addition, a quantitative analysis of machines’ health has also been offered. A health score has been calculated based on the spectral entropy in the start-up current to quantify the condition of the motor. To examine the rotor fault, a Finite Element Model (FEM) of the machine is simulated in the ANSYS 2D workbench. The suggested method has been validated with simulated data in multiple simulation scenarios with varying load torques to demonstrate the method's efficacy. Finally, the diagnosis method is tested against a publicly available data set related to the rotor bar fault.
查看更多>>摘要：? 2022 Elsevier LtdIn the near future, the railway is seen as the most important solution for reducing greenhouse gas emissions due to transportation. Investment in this sectors are ongoing, in order to increase both the level of service and energy efficiency. The adoption of recent technological solutions, as storage systems or reversible substations, could foster the efficiency, increasing the capability of recovering braking energy. The braking energy is very difficult to measure, it requires installing expensive measurement systems on board trains. In a previous paper the authors already faced this issue developing an accurate technique usable off-line. In the present paper a simplified method, easy to be implemented on train control unit, based only on already available data, is proposed. The paper describes the phenomena of interest and related measurement issues. The analytical model for the power measurement together with a deep analysis on the input quantities are presented. The uncertainty analysis of the proposed method is presented and the uncertainty budget is performed on a real test case. The metrological performances of the method show suitable accuracy level for train energy management.
查看更多>>摘要：? 2022 Elsevier LtdDeformation of directed energy deposition (DED) is an index to reflect the relationship among fabricating quality, parameters and process method. In the present work, Inconel 718 cylindrical walls are manufactured by hybrid additive and subtractive manufacturing (HASM) to investigate the deformation. In-situ and off-line measurements are used to detect the deformation of the cylindrical walls with laser displacement measurement sensor and precision contact probe. The finite element simulation is used to analyze the relationship among the temperature, stress and deformation. The effect of different interlayer dwell times (from 0 to 45 s) on residual stress and deformation are compared. The deformations of different positions and processing parameters are analyzed.
查看更多>>摘要：? 2022 Elsevier LtdThe increase in population and the crowding of cities bring along transportation problems. Thus, people are directed to public transportation to reduce the burden on transportation. Being informed correctly about the arrival time at the stops attracts passengers. In this study, machine learning methods with three-layer architecture were used to predict bus arrival time. The first layer processes the measured data and gives the prediction results of actual data. In the second layer, the residuals are predicted at the specified depth. In the third layer, the results of the previous two layers are integrated with three different approaches to calculate the final prediction. The case study was carried out on the data obtained from Istanbul public transportation and various machine learning methods were applied to the data using the traditional and the three-layer architecture. The experimental results showed that the three-layer architecture provided successful results with approximately 2.552 MAPE.
查看更多>>摘要：? 2022 Elsevier LtdCombined cycle power plants (CCPP) are among the most sophisticated, yet efficient, systems for producing electrical energy. Hence, simulating their performance has been an engineering hotspot toward sustainable developments. This paper employs novel soft computing methods for predicting electrical power (PE) output of CCPPs. To this end, a metaheuristic technique called electrostatic discharge algorithm (ESDA) is coupled with an artificial neural network (ANN) to create the proposed hybrid. Its performance is compared to several conventionally trained ANNs to investigate the effect of hybridization. By considering the influence of ambient temperature, exhaust vacuum, atmospheric pressure, and relative humidity, the PE is predicted through a 4 × 9 × 1 network. Among the conventional trainers, Levenberg-Marquardt emerged as the most promising one. However, the ESDA outperformed this algorithm in both training and testing phases. Accordingly, the used metaheuristic optimization could improve the robustness of the regular ANN in surmounting computational drawbacks. The ESDA-ANN is, therefore, introduced as a reliable predictive tool for the PE modeling, and the corresponding predictive formula is presented in the last part of this research.
查看更多>>摘要：? 2022 Elsevier LtdSelective, sensitive, and reproducible ion-selective electrodes containing dabigatran etexilate- phosphotungstate ion pair as a modifier have been fabricated to determine dabigatran etexilate in pure and pharmaceutical dosage form. The modified electrodes ion selective carbon paste electrode and ion selective pencil graphite electrode showed fast and linear response within a concentration range of 1.0 × 10?5 to 1.0 × 10?2 M and 1.0 × 10?6 to 1.0 × 10?2 M with a detection limit of 4.36 × 10?6 M and 4.26 × 10?7 M by ISCPE and ISGPE, respectively. Electrodes are selective to dabigatran etexilate over common excipients. The present study demonstrated the determination of dabigatran etexilate in pure and pharmaceutical dosage forms with high accuracy and precision.
NSTL
Elsevier