Acquisition Of Current Research Articles

Vibration reduction and energy harvesting of the marine stern shaft-bearing systems with triboelectric generator

The stringent requirements for vibration reduction in marine propeller shaft are essential due to the increased effects of transverse vibration. In order to effectively minimize the energy consumption and realize the energy harvesting during the process of vibration control, a triboelectric generator is proposed for the marine stern bearing-shaft systems by a combination of vibration reduction and energy harvesting. The vibration reduction is achieved using an adjustable damping magnetorheological shock absorber. The energy harvesting is realized through contact electrification and electrostatic induction during the vertical contact-separation of electrode plate. The Poincaré surface of the shaft and bearing demonstrates that the proposed triboelectric generator can be applicable for the vibration reduction and energy harvesting. Meanwhile, the controlled responses of suspension travel, soleplate deflection, acceleration of shaft and bearing, and forces are subjected to analysis. The energy harvesting process encompasses the acquisition of resistor current, PDMS charge, open-circuit voltage and electrical energy of the system. Moreover, the influence of various model parameters on both vibration reduction rate and electrical energy harvesting are discussed. It is anticipated that a more optimal satisfaction in terms of vibration reduction and energy harvesting can be attained through the adjustment of model parameter.

Analysis of single-phase grounding fault and its protection in the medium and low voltage distribution system

The single-phase ground fault of the medium and low voltage distribution system occurs most frequently in the distribution network. The fault should be eliminated in a short time. The single-phase ground short circuit fault that occurs when the neutral point of the power supply is not directly grounded in the medium and low voltage distribution network should be simulated and analyzed. The study seeks to understand the trend of voltage and current as well as the changes of its amplitude and phase when the fault occurs, which are consistent with the theoretical calculation and analysis. According to the analysis of single-phase grounding fault based on the simulated data, the acquisition of zero sequence current, the protection configuration, and the method of setting the point are discussed.

Development of Fixtures and Methods to Assess the Durability of Balance of Systems Components

The degradation of photovoltaic (PV) balance of systems (BoS) components is not well studied, but the consequences include offline modules, strings, and inverters; system shutdown; arc faults; and fires. A utility provider experienced a ∼30% failure rate in their power transfer chain, originally attributed to branch connectors. Field-failed specimen assemblies were, therefore, examined, consisting of cable connector, branch connector, and discrete fuse components. In this study, unused field-vintage specimens are examined using a benchtop prototype fixture to identify the most influential environmental stressors on BoS components as well as the effect of external mechanical perturbation. The prototype fixture was used to develop a perturbation capability for future use in the combined-accelerated stress testing chamber. The benchtop experiments were also used to develop the in-situ data acquisition of specimen current, voltage, and temperature. A significant increase in operating temperature (∼100 °C from ∼40 °C) and a different failure mode (arcing at the metal pins rather than overheating of the fuse filament) were observed promptly once periodic mechanical perturbation was applied. The current at failure was decreased from 35 A (measured for static specimens, with failure occurring in the fuses) to 15 A (for tests with mechanical perturbation, with failure at the male/female metal pin connection). After initial examination using X-ray computed tomography, the external plastic was machined away from failed specimens to allow for failure analysis, including the extraction of the internal convolute springs for morphological examination (optical and electron microscopy). Chemical composition analysis included energy-dispersive X-ray spectroscopy, differential scanning calorimetry, and Fourier transform infrared spectroscopy.

Quantitative Local Probing of Polarization with Application on HfO2 -Based Thin Films.

Owing to their switchable spontaneous polarization, ferroelectric materials have been applied in various fields, such as information technologies, actuators, and sensors. In the last decade, as the characteristic sizes of both devices and materials have decreased significantly below the nanoscale, the development of appropriate characterization tools became essential. Recently, a technique based on conductive atomic force microscopy (AFM), called AFM-positive-up-negative-down (PUND), is employed for the direct measurement of ferroelectric polarization under the AFM tip. However, the main limitation of AFM-PUND is the low frequency (i.e., on the order of a few hertz) that is used to initiate ferroelectric hysteresis. A significantly higher frequency is required to increase the signal-to-noise ratio and the measurement efficiency. In this study, a novel method based on high-frequency AFM-PUND using continuous waveform and simultaneous signal acquisition of the switching current is presented, in which polarization-voltage hysteresis loops are obtained on a high-polarization BiFeO3 nanocapacitor at frequencies up to 100kHz. The proposed method is comprehensively evaluated by measuring nanoscale polarization values of the emerging ferroelectric Hf0.5 Zr0.5 O2 under the AFM tip.

A New Convolutional Neural Network-Based System for NILM Applications

Electrical load planning and demand response programs are often based on the analysis of individual load-level measurements obtained from houses or buildings. The identification of individual appliances’ power consumption is essential, since it allows improvements, which can reduce the appliances’ power consumption. In this article, the problem of identifying the electrical loads connected to a house, starting from the total electric current measurement, is investigated. The proposed system is capable of extracting the energy demand of each individual device using a nonintrusive load monitoring (NILM) technique. An NILM algorithm based on a convolutional neural network is proposed. The proposed algorithm allows simultaneous detection and classification of events without having to perform double processing. As a result, the calculation times can be reduced. Another important advantage is that only the acquisition of current is required. The proposed measurement system is also described in this article. Measurements are conducted using a test system, which is capable of generating the electrical loads found on a typical house. The most important experimental results are also included and discussed in the article.

The data acquisition and control system for the operation of ASDEX pressure gauge for the measurement of neutral pressure in ADITYA Tokamak

Bayard-Alpert (BA) type hot cathode ionisation gauge is widely used to measure neutral pressure precisely in vacuum system below 10−3 Torr pressure. Neutral pressure measurement in magnetic confinement fusion experiments is quite challenging for standard BA type gauge due to higher pressure limitation and its ionisation is affected by strong magnetic and electrical fields. To overcome the above limitations, a special hot cathode ionisation gauge, named ASDEX Pressure Gauge (APG) system was developed by G. Haas at the Max-Planck-Institute, Germany. The APG system can work in high magnetic field up to 6 T and high temperature plasma environment with broad pressure measurement range from 10−1 to 10−6 mbar with fast response (<10 msec) and good noise immunity.In the present work, we report the design and development of control and data acquisition of ASDEX Pressure Gauge (APG) for ADITYA Tokamak to measure real time neutral pressure during the high temperature plasma. The developed system can achieve synchronous control of gauge controller using General Purpose Interface Bus (GPIB) and data acquisition of ion emission current of gauge head using Peripheral Component Interconnect (PCI) based data acquisition module. Initially, the APG calibration with standard BA type hot cathode ionization gauge had been carried out using the test set-up of low magnetic field and ultrahigh vacuum system with gases like H2, Ar, He. For APG calibration for various pressure ranges of these gases, precise gas feed control system has been developed using controller based hardware and LabVIEW based software. After testing and calibration, the APG was installed on ADITYA tokamak and calibrated under high magnetic field of ADITYA. The developed APG control system is configurable for presenting the gauge parameters before the plasma discharge. During plasma discharge, the analog signal equivalent to neutral pressure is acquired in real-time using simultaneous sampling analog to digital converter (ADC) module. The acquired raw data and processed real time pressure can provide valuable neutral pressure/density information of Tokamak plasma.

Assessment of the effect of a pulsed power supply on the HgTlI lamp

The objective of this work is to study the influence of a pulsed power supply on the energy efficiency of high-intensity discharge lamps in comparison with a pseudo-continuous ballast. The results presented in this paper concern the dynamic behaviour of discharges in mercury vapour doped with thallium iodide. The acquisition of the arc current, arc voltage and spectral radiation enables us to investigate the influence of the pulsed power supply on the electrical characteristics of the lamp such as the behaviour of the lamp conductance and spectral radiance. The analysis of the 577 nm mercury line’s response to the current pulse excitation allowed us to identify several phases. Good agreement has been found between simulation and experimental results.

Influence of polarity on mechanical properties of dissimilar resistance spot welds of DP 600/AISI 304 steels

The influence of polarity during resistance spot weld (RSW) of dissimilar lap joints on mechanical properties and failure mode is assessed in this work. A dissimilar lap joint was set using DP 600 dual phase steel with AISI 304 stainless steel. The experiments were performed on a medium-frequency direct current spot welding machine with proper data acquisition of voltage and welding current. Temperature evolution was also acquired by using IR camera. The mechanical properties of spot welds were evaluated by using a coach peel testing. The effect of welding current and welding time on mechanical properties was also evaluated. Correlations between polarity with the welding nugget size, failure mode, tensile strength, temperature evolution and dynamic resistance were analysed. The analysis confirmed that the polarity on dissimilar lap joints affects the behaviour of dissimilar RSWs.

Acquisition of the tide-induced Lagrangian residual current field by the PIV technique in the laboratory

In this paper, a new particle image velocimetry (PIV)-based measurement method is proposed to obtain the high-resolution tide-induced Lagrangian residual current field in the laboratory. A long gravity wave was generated to simulate the tide in a narrow tank full of water laden with PIV particles. Consecutive charge-coupled device (CCD) images were recorded with the studied layer illuminated with a laser beam. Two images separated by one tidal period were processed by applying the pattern-matching algorithm to get the horizontal tide-induced Lagrangian residual current field. The results coincide with sporadic results from the traditional surface-float tracing method, but with much higher spatial resolution and accuracy. Furthermore, it is found that the direct acquisition of the Lagrangian residual current may reduce the error at least by one order compared with those acquisition methods that require the detailed information of the tidal cycle.

Intelligent Battery Charger Based Design Based on MCU

This paper introduces a kind of intelligent battery charger based design based on MCU. The charger can complete real-time acquisition of battery voltage and current, and the charging process under intelligent control. It can automatically calculate the remaining charging time of the battery and adjust the parameters to adapt to a variety of battery charging. System management circuit also has a protective function, which can prevent the damage to the battery from overcharge and overtime.

Alternate Charging and Discharging of Capacitor to Enhance the Electron Production of Bioelectrochemical Systems

A bioelectrochemical system (BES) can be operated in both "microbial fuel cell" (MFC) and "microbial electrolysis cell" (MEC) modes, in which power is delivered and invested respectively. To enhance the electric current production, a BES was operated in MFC mode first and a capacitor was used to collect power from the system. Then the charged capacitor discharged electrons to the system itself, switching into MEC mode. This alternate charging and discharging (ACD) mode helped the system produce 22-32% higher average current compared to an intermittent charging (IC) mode, in which the capacitor was first charged from an MFC and then discharged to a resistor, at 21.6 Ω external resistance, 3.3 F capacitance and 300 mV charging voltage. The effects of external resistance, capacitance and charging voltage on average current were studied. The average current reduced as the external resistance and charging voltage increased and was slightly affected by the capacitance. Acquisition of higher average current in the ACD mode was attributed to the shorter discharging time compared to the charging time, as well as a higher anode potential caused by discharging the capacitor. Results from circuit analysis and quantitatively calculation were consistent with the experimental observations.

Solid electrolyte gas sensors based on cyclic voltammetry with one active electrode

Solid state gas sensors are cost effective, small, rugged and reliable. Typically electrochemical solid state sensors operate in either potentiometric or amperometric mode. However, a lack of selectivity is sometimes a shortcoming of such sensors. It seems that improvements of selectivity can be obtained in case of the electrocatalytic sensors, which operate in cyclic voltammetry mode. Their working principle is based on acquisition of an electric current, while voltage ramp is applied to the sensor. The current-voltage response depends in a unique way on the type and concentration of ambient gas. Most electrocatalytic sensors have symmetrical structure. They are in a form of pellets with two electrodes placed on their opposite sides. Electrochemical reactions occur simultaneously on both electrodes. In this paper results for sensors with only one active electrode exposed to ambient gas are presented. The other electrode was isolated from ambient gas with dielectric sealing. This sensor construction allows application of advanced measuring procedures, which permit sensor regeneration acceleration. Experiments were conducted on Nasicon sensors. Properties of two sensors, one with one active electrode and second with symmetrical structure, used for the detection of mixtures of NO2 and synthetic air are compared.

Mutual Impedance Extraction and Varactor Calibration Technique for ESPAR Antenna Characterization

An extraction and calibration technique is proposed that allows electronically steerable parasitic array radiator (ESPAR) antennas to achieve high efficiency and precision in performance characterization. The proposed technique is based on a reactive-near-field measurement or direct acquisition of RF current. We present a simple formulation that requires minimal current measurements to successfully extract the mutual impedance. Currents are predicted for an arbitrary combination of bias voltages that are used to control the reactance of varactor diodes integrated with the antenna's parasitic elements. These predicted currents are compared by conducting an experiment with a seven-element ESPAR. For the bias voltage combinations that have reasonably good symmetry, the differences in relative gain, beam direction and half power beam width (HPBW) actually fall within 0.5 dB, 4deg and 9deg, respectively. Directivity patterns obtained by calculating the predicted currents are verified with those obtained by calculating the directly measured currents. Furthermore, the calculated patterns are verified through comparison with far-field measurements in a conventional anechoic chamber. The differences in beam direction and HPBW are also found to be acceptable. Using the proposed technique, the required number of measurements is reduced from 85,766,121 to just 149 for a seven-element array

A Gated, Four-frame Pinhole Camera with Quantitative Image Acquisition

A gated, multiframe microchannel plate soft X-ray sensor with quantitative acquisition has been developed. The system is composed of an image acquisition system and a gated pinhole camera capable of taking four successive frames at a time resolution of ∼220 ps. The response of the system has been quantitatively investigated. To perform a quantitative evaluation of the captured X-ray images, the image acquisition and measurement of the phosphor current are executed simultaneously in the experiment. The system has been examined using a plasma X-ray source generated by a plasma focus device with an additional gas puff. The compression and bifurcation process of plasma hot spots in a neon puffed experiment has been successfully recorded. Quantitative analysis of the images indicates that an order of 1016 photons/(s·mm2·mrad2) emissions originate from the plasma in a soft X-ray region 6–14 Å.