Signal Pickup Research Articles

Electrochemical Impedance Spectra Measurements and Analysis of Polymer Electrolyte Membrane Electrolysis on Short Stack

Energy storage is becoming increasingly urgent as the share of fluctuating renewable energies increases in order to utilize the full potential of power plants and stabilize the grid in times of lower yields. Water electrolysis is therefore a promising solution for converting energy into hydrogen, which offers the opportunity of long term, even seasonal energy storage, albeit with lower round-trip efficiency compared to established battery technology.In a comparative technology assessment among AEM, SOEC, PEM, and AEL Polymer Electrolyte Membrane electrolysis excels in terms of power density >2 A/cm² and partial load stability, although it has disadvantages in terms on precious metal usage in catalysts and highly conductive corrosion resistant coatings for porous transport layers.In this work the method of electrochemical impedance spectroscopy will be investigated to gain insight into kinetics and transport processes at different operation conditions. Furthermore, we will investigate degradation losses and establish a state of health monitoring at a short stack level. Since stack designs for atmospheric PEM-Electrolysis enables easy single cell voltage monitoring the Impedance response to a superimposed applied AC-current signal can be picked up from each cell individually. Yet, the large footprint of “technical cells” leads to very low overall impedance thus making signal pickup and analysis more challenging compared to single cell or RDE measurements on small active area. Applying a precise high power signal, precise measurement of small AC contributions at a high DC background and the reduction of interferences with other components such as interferences from the power line or ripples in the DC part as well as temporal and spatial homogeneity of the sample under test are posing constraints for the recording and interpretation of electrochemical impedance spectra.We studied different setups of power electronics with add-on impedance spectrometers, both in serial and parallel configuration. The test object, shown in figure1b), was a 282 cm² active area PEM-electrolysis short stack of 3 cells derived from a an open source “generic PEM fuel cell stack” design which was operated at atmospheric pressure in a Greenlight G200 test rig (figure1a)) modified for electrolysis operation. A zahner IM6 impedance spectrometer in combination an EL1000 was used for the modulation of the alternating current signal. For comparison AC-modulation using a tunable AC frequency generator already implemented in the DC Power supply was studied. The current and voltage signals in this setup were recorded and analyzed using a high-speed transient recorder. The resulting impedance spectra of both devices are shown in Figure 1c) at different current densities. The spectra recorded were analyzed by standard methods via assignment of equivalent circuits. We studied the reproducibility and assignability of different time constants to different processes and equivalent circuit parameters depending on the operating conditions and the actuation amplitudes.From the results of these studies, we derived optimization potential for the electrolysis stack design. Furthermore, we studied degradation processes as a consequence of accelerated stress tests providing a data basis for electrolyzer stack operation and predictive maintenance. Figure 1

Longitudinal bunch-by-bunch feedback systems in storage rings: Phase vs. energy sensing

Bunch-by-bunch feedback (FB) systems are widely employed in charged-particle storage rings to suppress beam instabilities. In the longitudinal plane, the correction applied by a conventional FB system to the beam motion is an energy kick based on the signal originating from a time-of-arrival pick-up device (phase sensing). In this Note, we make a comparison with an alternate approach where the pick-up signal originates from the detection of the energy error. We show that for equal FB gain and input-impulse length the achievable damping rates in the two cases are essentially the same.

Virtual cavity probe for the real-time identification of cavity burst-noise type in superconducting radio-frequency systems

Burst-noise events are primary trip sources at the China Accelerator Facility for superheavy Elements (CAFE2), characterized by a rapid burst noise in the cavity pick-up signal categorizable into three distinct types: flashover, electronic quench (E-quench), and partial E-quench. Herein, we design an algorithm identifying the burst-noise event types in real time to realize a real-time discrimination of the three types of burst-noise events. This algorithm is based on a virtual cavity probe constructed with the forward and reflected signals of the cavity and integrated into a field-programmable gate array (FPGA). Moreover, we introduce an innovative method for calibrating the transmission delay in channels. This FPGA-based low-level radio-frequency algorithm identifies the burst-noise event type in real time. Its effectiveness has been validated in the CAFE2 facility, offering valuable data support for future advancements in machine learning-based fault classification and dark-current characterization.

Development of a non-intercepting weak beam current measurement electronics for Heavy Ion Accelerator Facility in Lanzhou.

Non-destructive measurements of low-intensity charged particle beams are particularly challenging for beam diagnostics. At the Heavy Ion Accelerator Facility in Lanzhou (HIRFL), beams with weak currents below 1 µA are often provided for experiments. The detection of such low beam current is below the threshold of typical standard beam current transformers. Therefore, a low-intensity monitoring system is developed by using a sensitive capacitive pick-up (PU) and low-noise electronics. This device measures beam currents by digitally analyzing the amplitude of the PU signals using a homodyne detection scheme. During lab tests, the amplitude nonlinearity is <0.5% in the operational range of 1 nA-45 µA and the amplitude resolution is 0.94 nA. At present, four measurement systems for low beam currents are installed at HIRFL for the monitoring of standard operating conditions with low beam currents below 1 µA. After an absolute calibration with a Faraday cup, it can be used for accurate beam intensity measurement with a current resolution of about 1 nA.

Off-resonance electronic detection and cooling of ions in a Penning trap

We present a non-destructive electronic detector for stored charged particles in a Penning trap that uses a symmetric electrode arrangement for signal pickup and a resonator without tap. This system has advantageous off-resonance features which are demonstrated by means of detection and cooling measurements with highly charged ions in a cryogenic Penning trap. In particular, it allows for particle detection across a wide range of frequencies that is not concomitant with cooling and offers a novel way to tune a trap with the help of non-destructive measurements on large particle ensembles.

Method for the P-wave arrival pickup of rock fracture acoustic emission signals under strong noise

This research aimed to investigate the accuracy of picking of P-wave arrival times in rock fracture acoustic emission signals. In order to simulate the mining scenario, Gaussian white noise and pulse noise were added to the data collected in the laboratory. Complete ensemble empirical mode decomposition with adaptive noise + Wavelet (CEEMDAN + Wavelet) was improved in this paper, where the Spearman rank correlation coefficient was adopted to effectively select intrinsic mode functions for denoising which retained the inherent characteristics of the rock fracture signal. The absolute amplitude and energy change rate of the envelope signal, calculated based on the Hilbert transform, were used as the input of the short term average/long term average (STA/LTA) normalization algorithm to pickup the P-wave arrival time. The reliability of this method was tested on 30 groups of recorded rock fracture laboratory data and 60 groups of added noise data. Taking the manual pickup results as the standard, the errors of CEEMDAN + Wavelet + STA/LTA + AIC (Akaike information criterion) method with the absolute amplitude of the signal as the input are all within 10 ms, and 86.67% of the results are within 5 ms. The method proposed in this paper effectively addressing the issue of false pickup caused by the sensitivity of AIC and traditional STA/LTA method for strong noise, and achieving relatively high accuracy and stability in processing low signal-to-noise ratio signals. This work contributes to monitor microscopic changes in rock bodies and is of great significance for the prediction and monitoring of geological disasters.

Button-Type Beam Position Monitor Development for Fourth-Generation Synchrotron Light Sources: Numerical Modeling and Test Bench Measurements.

This paper addresses the design of beam position monitor (BPM) devices suitable for fourth-generation diffraction-limited X-ray storage rings. Detailed investigations of the electromagnetic (EM) phenomena occurring inside the component under various working conditions are carried out by considering different BPM EM models defined by their geometry and materials. Moving from a theoretical characterization of the common round geometry, rhomboidal structures are studied through a careful numerical analysis relying on advanced computer-aided tools. Several critical elements, such as wakefields, pick-up signal extraction, and trapped and propagating modes, are explored from the simulation point of view and from the experimental one, by deploying a manufactured microwave test bench, which is employed to measure the radio frequency behavior of a BPM prototype built at Elettra Sincrotrone Trieste. The aim of the proposed study is to identify a satisfactory tradeoff between achievable performance and practical realizability for BPM devices operating in last-generation light sources.

Temperature drift suppression for micro‐electro‐mechanical system gyroscope based on vibrational‐displacement control with harmonic amplitude ratio

AbstractMicro‐electro‐mechanical system gyroscope detection output is susceptible to drift due to ambient temperature variations. Furthermore, the drive‐mode vibration amplitude is affected by the signal pickup circuit and structural parameters, which significantly influence the temperature drift of the bias and scale factor (SF). This study proposes a vibration amplitude control method based on harmonic amplitude sideband‐ratio (SBR), namely SBR‐AGC, which characterizes the vibration amplitude using the harmonic amplitude ratio of the vibrational electrical signal. The constancy of vibration amplitude is maintained via closed‐loop control to suppress bias and SF temperature drift. The experimental results on cobweb‐like disk resonator gyroscope reveal that the temperature coefficient of bias in the SBR‐AGC mode lies within −20 to 60°C and decreases by 36%, and the temperature coefficient of the SF lies within −10 to 50°C and decreases by 49.7%. Therefore, the environmental adaptability of the gyroscope is effectively improved.

Design and Performance Evaluation of a Directional Telescopic Microphone for Enhanced Environmental Sound Capture

A directional telescopic microphone is composed of two parts. One is the pick-up circuit made up of 34 different length aluminum tubes to respond in a specific frequency. The use of a sensitive FET mic is to pick up a sound from a direction. The signal from the FET mic will be feed to the microphone preamplifier in order to amplify the signal. The Equalization and Attenuation circuit is responsible for the balancing and boosting the low and high frequency. The pick-up signal can be easily recordedto a device through the recording unit or can be heard through the speaker, driven by a power amplifier in order to set up the signal. The main purpose of the gadget is to be used in an environmental study. This can pick up sound that was not normally heard by human ear in a specify distance.

Detection of flaws in austenitic stainless steel plate using eddy current testing

This study proposes an eddy current testing (ECT) probe to detect flaws in finite thickness austenitic stainless-steel plates. In order to obtain the spatial magnetic field distribution and the detection sensitivity of the probe in different scanning directions, a 3D model of ECT is simulated. The detection ability of ECT probe is verified by experiment. To detect surface flaws and subsurface flaws, 2.0 kHz and 1.0 kHz are chosen as excitation frequencies respectively. In addition, the pick-up signal goes through the amplification circuit and the signal conditioning module to improve the signal-to-noise ratio. Finally, the experimental results are compared with those from numerical simulation. Both results show the ability of the probe to detect flaws in the austenitic stainless-steel plate.

Application Research of Pipe Pile Detection Technology based on Impact Elastic Wave

The practical application of the low strain method in the detection of prestressed pipe piles is not ideal. After investigation, there is a practical and feasible method, namely the impact elastic wave method, which can be used for nondestructive testing of prestressed pipe piles. This paper proposes a nondestructive testing technology for prestressed pipe piles, the impact elastic wave method, and introduces a signal pickup device for prestressed pipe piles with side walls and bottom damping, improving the technical bottleneck of low strain method for detecting hollow thin-walled structures such as pipe piles, and solving the problems of detecting the length and integrity of hollow thin-walled prefabricated pipe piles. Through large-scale field measurement and on-site pile excavation inspection of all known pipe piles, it has been shown that this detection method can more effectively detect pipe piles. Through measurement and inspection of all known pipe piles, a standard inspection process for the length and integrity of all pipe piles can be established and effectively applied to the inspection of actual projects; Through field inspection, the accuracy of the testing method for pipe pile measurement has been confirmed, and a fast, effective and reliable method for pipe pile measurement has been proposed.

Model of a Micromechanical Modal-Localized Accelerometer with a Sensitive Element in the Form of a Beam with an Initial Deflection

The present study is devoted to mathematical modeling of the proposed new architecture of a microelectromechanical modally localized acceleration sensor (MEMS accelerometer/gravimeter) with a sensitive element in the form of a microbeam pinched at both ends with an initial deflection, made in the form of the first asymmetric mode of free vibrations. The article demonstrates that with an asymmetric form of the initial deflection in the region of positive axial forces, there are zones of proximity of the frequency branches corresponding to the second symmetric and the first asymmetric vibration modes. When the required value of the axial tensile force in the microbeam is provided structurally, this effect can be used, in particular, to measure the axial component of the transfer acceleration according to the principle of amplitude modal localization. The possibility of heating the sensitive element with the help of an electric current flowing through the microbeam, provided in the sensor layout, makes it possible to control the operating point of the oscillation mode and, thus, to vary the range of measured accelerations and the degree of sensor sensitivity within a very wide range. The configuration of the oscillation excitation and output signal pickup electrodes proposed in the article makes it possible, with the help of a feedback loop, to stabilize the oscillation amplitude at the required level in the working (third) symmetrical form and, at the same time, to measure the oscillation amplitude associated with the change in the value of the measured component of the portable acceleration according to the asymmetric form. Thus, a mathematical model of an original modal-localized accelerometer (gravimeter) containing a single sensitive microbeam element and involving the effect of energy exchange between its various modes of vibration is proposed and investigated in the article.

Timing resistive plate chambers for thermal neutron detection with 3D position sensitivity

An optimized design of a neutron detector based on timing RPCs (Resistive Plate Chambers) with boron-10 neutron converters is presented. The detector is composed of a stack of ten double gap RPCs with aluminium cathode plates coated on both sides with 10B4C. This design enables simultaneous determination with high accuracy of both the neutron time-of-flight (down to ns resolution) and the interaction position in 3D (down to 0.25 mm resolution across and ∼1 mm along the beam). It is shown that the detection efficiency can approach 60% for neutrons with lambda = 4.7 Å. A new geometry with less material budget is introduced for the signal pick-up strip arrays. The results of simulation-based optimization of the design are reported considering the trade-off between the detection efficiency, the count rate capability and the amount of elastic scattering on the detector components.

A reconfigurable Micro-channel plate “RSP” detector for wide-range application in charged particle detection

We have developed an MCP detector with reconfigurable read-out which is capable of recording the position and time information for single particle counting and alternatively of operating at high particle flux with optical read-out. This is achieved by a Resistive Screen with embedded Phosphor (RSP) anode. On demand, signal pickup electrodes such as a delay-line array can be attached or removed without interfering with vacuum, allowing easy switching between the different operation modes. We show tests of a prototype.

A Numerical Scheme for Fast and High Accuracy Simulation of Motion-Induced Eddy Current Testing Signals

ABSTRACT In this paper, an efficient numerical scheme and corresponding fast solver are proposed and implemented for rapid and high-accuracy numerical calculation of the motion-induced eddy current testing (MIECT) forward problems. First, inspired by the time-domain numerical formulation of the MIECT problem, a DFT-based numerical scheme in the frequency-domain was proposed through DFT of the transient excitation magnetic field signals at conductor surface caused by the moving permanent magnet of the MIECT probe. Second, a fast-forward simulator was implemented by further improving the existing Ar code for single-frequency ECT problem and adopting databases approach using the unflawed field information solved and stored a priori. As the key of the fast simulation of the MIECT signal perturbed by defects, a scheme to calculate the pickup signal perturbations was proposed and validated based on the reciprocity theorem. Finally, the validity of the numerical schemes and corresponding fast-forward solver was verified through comparing simulation results with experimental signal. Compared with the full analysis domain methods, the fast simulator can save computational burden up to 1000 times on the premise of not affecting the numerical precision, which enables its being adopted in the inverse analysis of MIECT signals for defect sizing.

Method for measuring voltages in channels of a hemispherical resonator gyroscope with an arbitrary orientation axes

&lt;span&gt;The article deals with issues related to solid wave gyroscopes, which are used as a sensor in inertial navigation systems. The article considers a variant of solving problem, when oscillations of the resonator are excited in directions that coincide with their own axes, oriented a priori is unknown. The main contribution this article is the method is proposed for measuring signal amplitudes in virtual main and quadrature channels, the orientation of which does not coincide with the orientation of the signal pickup electrodes. This is achieved by modeling algorithms for measuring the slope of the resonator's own axes and signal amplitudes in virtual channels are evaluation. In order to verify the adequacy of the proposed models simplified calculation formulas for programming microcontrollers are presented. An estimate of the error due to the use of simplified formulas is made. It is assumed that the use of this method will reduce the requirements for the quality of balancing the resonators of gyroscopes. The findings will be useful for mass production of navigation systems with gyroscopes, which have a small drift and are capable of experiencing large shock linear accelerations, for example, in underground inclined drilling, and in meteorological rockets.&lt;/span&gt;

Novel Ultraviolet and Ionizing Radiation Detectors Made From TiO Wide-Bandgap Semiconductor

We describe the fabrication and characterization of a novel ultraviolet (UV) and ionizing radiation detector using a polycrystalline TiO2 wide-bandgap semiconductor as the active material. The detector geometry we have developed and tested is a polycrystalline TiO2 thin film with planar electrode contacts for signal pickup. Several prototypes were fabricated using two single-step techniques. We present the dc characterization of these devices and the signal response to the UV light and low-energy proton beam irradiation. The detector prototypes show excellent dc characteristics and fast ac signal response at bias voltage as low as 50 V.

High frequency eddy current inspection of fibre placement in Carbon Fibre Reinforced Polymer Composites

This paper presents experimental and simulation studies of high frequency eddy current non-destructive testing (NDT) methods for inspection of carbon fibre reinforced polymer (CFRP) composites. It is well known that CFRP composite materials are widely used in industry as structural components, and products based on such materials are increasingly developed and introduced to market. In recent years, non-conventional eddy current method operating at high frequencies for NDT of composites begins to attract attention. It provides a non-contact, couplant-free option of inspection when compared with the other NDT methods currently used in industry. As eddy current relies on fibre fabrics in individual plies to form the current pathways, the eddy current paths in composite are unsurprisingly complex due to the structural features of composite laminates when compared with that in homogenous conducting metals for which conventional eddy current NDT is often used in industry. It will be noted that the knowledge is still limited so far about the eddy current distributions in composite laminates due to lack of effective theoretical and numerical models. This paper will focus on the development of a new numerical model that is suitable for use in simulations of high frequency eddy current inspection of fibre placements. An effective model is desirable for understanding the performance dependence of the eddy current testing method on the material properties, composite structural features, and other parameters involved. In this model, the fibre tow layout of individual plies is taken into consideration. The collection of the pickup signals by the sensor probe shows clear images of the fibre placement in different layers. The simulation results are compared with experimental results of fibre placement imaging. The model is useful for understanding the physical process for inspection of composites using high frequency eddy current methods, and for studying the influence of the controllable parameters involved.

Review of Minimally Invasive and Invasive MEMS Devices for Biomedical Diagnostic Applications: Design Aspects

The demand of MEMS biosensors in biomedical applications is enormous which has driven the review of such devices. Various biosensors that are available in the market and under research are inadequate in providing pickup and amplification of the bio-signals for diagnosis and treatment purposes. In this review, various biosensors implemented and deployed through invasive and non-invasive techniques are reviewed to determine their adequacy in diagnosis and treatment. A MEMS device also has been specifically designed for the pickup of intra-ocular pressure for early diagnosis of glaucoma. Piezoresistive type pressure sensor is designed to provide better accuracy in the pickup of such biomedical signals. The designed device which is analyzed using the COMSOL Multiphysics provided better sensitivity of around 26.6mV/V/MPa and a non-linearity of &lt; 1%, which will promote better diagnosis.

State-vector geometry and guided-wave physics behind optical super-resolution.

We examine the state-vector geometry and guided-wave physics underpinning spatial super-resolution, which can be attained in far-field linear microscopy via a combination of statistical analysis, quantum optics, and spatial mode demultiplexing. A suitably tailored guided-wave signal pickup is shown to provide an information channel that can distill the super-resolving spatial modes, thus enabling an estimation of sub-Rayleigh space intervals ξ. We derive closed-form analytical expressions describing the distribution of the ξ-estimation Fisher information over waveguide modes, showing that this information remains nonvanishing as ξ → 0, thus preventing the variance of ξ estimation from diverging at ξ → 0. We demonstrate that the transverse refractive index profile nQ(r) tailored to support the optimal wave function ψQ(r) for super-resolving ξ estimation encodes the same information about ξ as the entire manifold of waveguide modes needed to represent ψQ(r). Unlike ψQ(r), nQ(r) does not need a representation in a lengthy manifold of eigenmodes and can be found instead via adaptive feedback-controlled learning.