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Portable raman spectrometer for maritime security applications
PublikacjaThe fast identification of explosives, narcotics and other chemicals carried on board of ships or transported in containers to the harbors is an important problem of maritime security. Raman spectroscopy is widely used for fast identification of various chemicals. Continuous progress in the field of photonics has resulted in commercial availability of low-power compact Raman spectrometers which can be integrated into portable systems....
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A nine-input 1.25 mW, 34 ns CMOS analog median filter for image processing in real time
PublikacjaIn this paper an analog voltage-mode median filter, which operates on a 3 × 3 kernel is presented. The filter is implemented in a 0.35 μm CMOS technology. The proposed solution is based on voltage comparators and a bubble sort configuration. As a result, a fast (34 ns) time response with low power consumption (1.25 mW for 3.3 V) is achieved. The key advantage of the configuration is relatively high accuracy of signal processing,...
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Active Control of Highly Autocorrelated Machinery Noise in Multivariate Nonminimum Phase Systems
PublikacjaIn this paper, a novel multivariate active noise control scheme, designed to attenuate disturbances with high autocorrelation characteristics and preserve background signals, is proposed. The algorithm belongs to the class of feedback controllers and, unlike the popular feedforward FX-LMS approach, does not require availability of a reference signal. The proposed approach draws its inspiration from the iterative learning control...
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Towards classification of patients based on surface EMG data of temporomandibular joint muscles using self-organising maps
PublikacjaThe study considers the need for an effective method of classification of patients with a temporomandibular joint disorder (TMD). The self-organising map method (SOM) was applied to group patients and used together with the cross-correlation approach to interpret the processed (rectified and smoothed by using root mean square (RMS) algorithm) surface electromyography signal (sEMG) obtained from testing the muscles (two temporal...
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Quality Evaluation of Voice Transmission Using BPL Communication System in MV Mine Cable Network
PublikacjaThis article presents results of a quality evaluation study, considering voice transmission in a 6 kV medium voltage cable network using the BPL (Broadband over Power Line) communication system. The tests are carried out under real mining conditions for the selected power cable without voltage, earthed at both sides. Such a method of monitoring work conditions is of great importance, especially during a disaster. Power cables are...
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Analysis of Video Transmission Capabilities in a Simulated OFDM-Based Supplementary BPL-PLC System
PublikacjaThe design and maintenance of a reliable communication system, especially in harsh working conditions for the oil and mining industry, brings many challenges. With the use of a video transmission system, one can monitor the crew and their working environment. Broadband over power line–power line communication (BPL-PLC) seems an ideal medium for such a service, since it enables the use of the existing wired infrastructure for supplementary...
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Optical properties of thin TiO2 film deposited on the fiber optic sensor head
PublikacjaThe presented study was focused on investigation of the titanium dioxide (TiO2) thin film deposited on the fiber tip. The intention of this investigation was using TiO2 film in the construction of the optical fiber sensor head. In the demonstrated construction TiO2 thin layer was deposited on the tip of a commonly used telecommunication single mode optical fiber (SMF-28) by means of the Atomic Layer Deposition (ALD). Thickness...
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GAS SENSORS WITH TEMPERATURE MODULATION – AN OVERVIEW
PublikacjaAlthough different methods of improving semiconductor gas sensor properties have been proposed, a technique involving temperature modulation seems to be the most promising. Semiconductor gas sensors working with modulated temperature can be more stable and are more selective comparing with sensor working at one temperature. In this paper, various approaches to temperature modulation are reviewed.
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Technological substitution in Asia
PublikacjaThis book provides extensive evidence on information and communication technologies development diffusion patterns, unveils specific ‘network effects’ that enhance rapid spread of ICT, and detect major macroeconomic determinants of this process, across 36 Asian economies over the period 1980-2015. Moreover, this research traces country-specific patterns of the unique process. We consider two types of technological substitution,...
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Polymer based thick films - material quality and interface resistance evaluation
PublikacjaThe properties of polymer based thick film layers mede using different resistive pastes and dipping silvers have been studied. The composite of carbon and graphite (C/Gr) conducting particles suspended in different polymer vehicles were used for preparation resistive layers. Interface resistance Rc created between dipping silver (DiAg) contact layer and resistive layer was determined from the surface potential distribution measurements...
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Error analysis of calculating average d-q current components using Regular Sampling and Park transformation in FOC drives
PublikacjaIn electric drives using voltage source inverters, motor currents contain ripple component resulting from pulse-width modulated (PWM) voltage. The frequency range of the ripples is much higher than the bandwidth of current control. Therefore the control is performed on the basis of a fundamental current component, i.e. average value with the averaging time being the PWM period. In majority of cases the average current is measured...
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Subjective Quality Evaluation of Underground BPL-PLC Voice Communication System
PublikacjaDesigning a reliable voice transmission system is not a trivial task. Wired media, thanks to their resistance to mechanical damage, seem an ideal solution. The BPL-PLC (Broadband over Power Line – Power Line Communication) cable is resilient to electricity stoppage and partial damage of phase conductors. It maintains continuity of transmission in case of an emergency situation, including paramedic rescue operations. These features...
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Subjective and Objective Quality Evaluation Study of BPL -PLC Wired Medium
PublikacjaThis paper presents results of research on the effectiveness of bi-directional voice transmission in a 6 kV mine cable network using BPL-PLC (Broadband over Power Line - Power Line Communication) technology. It concerns both emergency cable state (supply outage with cable shorted at both ends) and loaded with distorted current waveforms. The narrowband (0.5 MHz–15 MHz) and broadband (two different modes, frequency range of 3 MHz–7.5...
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Finite-difference time-domain analyses of active cloaking for electrically-large objects
PublikacjaInvisibility cloaking devices constitute a unique and potentially disruptive technology, but only if they can work over broad bandwidths for electrically-large objects. So far, the only known scheme that allows for broadband scattering cancellation from an electrically-large object is based on an active implementation where electric and magnetic sources are deployed over a surface surrounding the object, but whose ‘switching on’...
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Automatic localization and continous tracking of mobile sound source using passive acoustic radar
PublikacjaA concept, practical realization and applications of the passive acoustic radar for localization and continuous tracking of fixed and mobile sound sources such as: cars, trucks, aircrafts and sources of shooting, explosions were presented in the paper. The device consists of the new kind of multi-channel miniature three dimensional sound intensity sensors invented by the Microflown company and a group of digital signal processing...
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Time-domine Dipole Fields in acoustic and Elektromagnetics
PublikacjaThe ultrawideband (UWB) radio technique presents a challenge not just for technology. The UWB carrier-free pulses act at a close distance, their electromagnetic fields being very different from classic monochromatic plane wave. The author proposes to adapt a time-domian approach to analysis of broadband spherical fields, both acoustic and electromagnetic, in fundamental cases of quasi-point physical sources.
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Continuous wave sonar with hyperbolic frequency modulation keyed by pseudo-random sequence
PublikacjaA CW FM type sounding signal is used in the classical solution of silent sonar. While the signal provides a relatively simple implementation of digital signal processing, and ensures good detection conditions, unfortunately, in the presence of the Doppler effect, distance measurement results tend to be wrong. This is due to the fact that the received signal’s instantaneous frequency value is dependent both on the distance to the...
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Real-time speech-rate modification experiments
PublikacjaAn algorithm designed for real-time speech time scale modification (stretching) is proposed, providing a combination of typical synchronous overlap and add based time scale modification algorithm and signal redundancy detection algorithms that allow to remove parts of the speech signal and replace them with the stretched speech signal fragments. Effectiveness of signal processing algorithms are examined experimentally together...
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Analogue GPS repeater
PublikacjaThis article concerns the problem of difficulty in correct indoor Global Positioning System (GPS) signals reception due to attenuation. Radio signal repeaters are proposed as means to solve this problem. Firstly, the GPS signal characteristics are described, emphasizing their low power in the point of reception. In the second part, various applications of GPS signal repeater, where indoor GPS signals reception is required, are...
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Efficiency of IEEE 802.15.4a UWB Impulse Radio Spectrum Shaping
PublikacjaThis paper presents results of impulse radio signal spectrum shaping efficiency investigations. Basic parameters of IEEE 802.15.4a UWB signal and outline of proposed spectrum shaping methods are briefly described. The main part of the paper presents influence of signal and algorithms parameters on the results of spectrum shaping.
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Digital Gaps and Economic Inequalities in MENA Countries: An Empirical Investigation
PublikacjaThis research contributes to the present state of the art by examining changes in cross-country inequalities in digital technologies deployment and economic performance. Our empirical target builds on the hypothesis that rapid global diffusion of digital technologies unequivocally leads to gradual eradication of cross-country digital gaps and cross-country inequalities in terms of deployment of ICT; the technology convergence occurs....
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Suppression of distortions in signals received from Doppler sensor for vehicle speed measurement
PublikacjaDoppler sensors are commonly used for movement detection and speed measurement. However, electromagnetic interference and imperfections in sensor construction result in degradation of the signal to noise ratio. As a result, detection of signals reflected from moving objects becomes problematic. The paper proposes an algorithm for reduction of distortions and noise in the signal received from a simple, dual-channel type of a Doppler...
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A method for testing the wide-sense stationary uncorrelated scattering assumption fulfillment for an underwater acoustic channel
PublikacjaWide-sense stationary and uncorrelated scattering (WSSUS) assumptions are often applied for the statistical description of wireless communication channels. However, in the case of underwater acoustic channels the WSSUS model is of limited value. The degree of similarity of in-phase and quadrature components of the channel impulse response, measured with the use of bandpass modulated signals, can be used as an indicator of WSSUS...
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Speech codec enhancements utilizing time compression and perceptual coding
PublikacjaA method for encoding wideband speech signal employing standardized narrowband speech codecs is presented as well as experimental results concerning detection of tonal spectral components. The speech signal sampled with a higher sampling rate than it is suitable for narrowband coding algorithm is compressed in order to decrease the amount of samples. Next, the time-compressed representation of a signal is encoded using a narrowband...
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Arm EMG Wavelet-Based Denoising System
PublikacjaThese paper presents research results of muscle EMG signal denoising. In the same time two muscles were examined - an adductor muscle (biceps brachii) and an abductor muscle (tricpeps brachii). The EMG signal was filtered using the wavelet transform technique, having selected the crucial parameters as: wavelet basis function (Daubechies 4), 10 th decomposition level, threshold selection algorithm (Heurestic) and a sln rescaling...
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Reversible data hiding in encrypted DICOM images using sorted binary sequences of pixels
PublikacjaIn this paper, a novel reversible data hiding method for encrypted DICOM images is proposed. The method utilizes binary decomposition of the input data paired with a sorting process of the obtained binary sequences to ensure efficient data embedding in each predefined data block for specific most significant bit (MSB) planes while exploiting the properties of run-length encoding. The proposed scheme is lossless, and based on the...
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Finite-window RLS algorithms
PublikacjaTwo recursive least-squares (RLS) adaptive filtering algorithms are most often used in practice, the exponential and sliding (rectangular) window RLS algorithms. This popularity is mainly due to existence of low-complexity versions of these algorithms. However, these two windows are not always the best choice for identification of fast time-varying systems, when the identification performance is most important. In this paper, we...
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Adaptive identification of sparse underwater acoustic channels with a mix of static and time-varying parameters
PublikacjaWe consider identification of sparse linear systems with a mix of static and time-varying parameters. Such systems are typical in underwater acoustics (UWA), for instance, in applications requiring identi- fication of the acoustic channel, such as UWA communications, navigation and continuous-wave sonar. The recently proposed fast local basis function (fLBF) algorithm provides high performance when identi- fying time-varying systems....
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Reduction of parasitic pitch variations in archival musical recordings
PublikacjaA new method for reducing parasitic pitch variations in archival audio recordings is presented. The method is intended for analyzing movie soundtracks recorded in optical films. It utilizes image processing for calculating and reducing effects of tape shrinkage being one of the main reasons for parasitic pitch variations in audio accompanying moving images. As long as the film tape characteristics are known the new method can be...
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Karhunen-Loeve-based approach to tracking of rapidly fading wireless communication channels
PublikacjaWhen parameters of wireless communication channels vary at a fast rate, simple estimation algorithms, such as weighted least squares (WLS) or least mean squares (LMS) algorithms, cannot estimate them with the accuracy needed to secure the reliable operation of the underlying communication systems. In cases like this, the local basis function (LBF) estimation technique can be used instead, significantly increasing the achievable...
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A self-optimization mechanism for generalized adaptive notch smoother
PublikacjaTracking of nonstationary narrowband signals is often accomplished using algorithms called adaptive notch filters (ANFs). Generalized adaptive notch smoothers (GANSs) extend the concepts of adaptive notch filtering in two directions. Firstly, they are designed to estimate coefficients of nonstationary quasi-periodic systems, rather than signals. Secondly, they employ noncausal processing, which greatly improves their accuracy and...
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Matrix-based robust joint fingerprinting and decryption method for multicast distribution of multimedia
PublikacjaThis paper addresses the problem of unauthorized redistribution of multimedia content by malicious users (pirates). The solution proposed here is a new joint fingerprinting and decryption method which meets the requirements for both imperceptibility and robustness of fingerprints and scalability in terms of design and distribution of fingerprinted multimedia content. The proposed method uses a simple block cipher based on matrix...
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Depth Determination Accuracy of the Modified Prony Method in a Swath Mapping Application
PublikacjaThis article presents the performance of the modified Prony method in a swath mapping application. Depth determination accuracy is assessed by processing raw signal acquired by an EdgeTech 6205 swath bathymetry system over flat seafloor. An updated version of the method, proposed previously by the authors, is used to determine the number of signal echoes. The number of signal echoes is essential for performing the low-rank approximation...
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New method of IEEE 802.15.4a UWB Impulse Radio Spectrum Shaping
PublikacjaThis paper presents a new technique of IEEE 802.15.4a ultra-wideband signal spectrum control, based on changes in sequences of transmitted pulses with very short duration time. Basic parameters of UWB signal and outline of proposed spectrum shaping methods are briefly described. The main part of the paper presents influence of signal and algorithms parameters on the results of spectrum shaping.
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Transient detection for speech coding applications
PublikacjaSignal quality in speech codecs may be improved by selecting transients from speech signal and encoding them using a suitable method. This paper presents an algorithm for transient detection in speech signal. This algorithm operates in several frequency bands. Transient detection functions are calculated from energy measured in short frames of the signal. The final selection of transient frames is based on results of detection...
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Wavelet filtering of signals without using model functions
PublikacjaThe effective wavelet filtering of real signals is impossible without determining their shape. The shape of a real signal is related to its wavelet spectrum. For shape analysis, a continuous color wavelet spectrogram of signal level is often used. The disadvantage of continuous wavelet spectrogram is the complexity of analyzing a blurry color image. A real signal with additive noise strongly distorts the spectrogram based on continuous...
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Distance measurement errors in silent FM-CW sonar with matched filtering
PublikacjaThe secretiveness of sonar operation can be achieved by using continuous frequency-modulated sounding signalswith reduced power and significantly prolonged repeat time. The application of matched filtration in the sonarreceiver provides optimal conditions for detection against the background of white noise and reverberation, and avery good resolution of distance measurements of motionless targets. The article shows that target...
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237Np Mössbauer effect study on NpFeAsO
PublikacjaWe report 237Np Mössbauer measurements on NpFeAsO. The Np atoms were found to occupy only one crystallographic site. The value of the isomer shift (δ ∼ 9.1 mm s−1 versus NpAl2) indicates a 5f4 electronic configuration (Np3+ ions). The magnetic ordering of the Np sublattice below 60 K is established and the saturated ordered magnetic moment is determined to be 1.73μB at 3.6 K. The unique set of hyperfine parameters exclude a modulated...
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Stress Detection of Children With ASD Using Physiological Signals
PublikacjaThis paper proposes a physiological signal-based stress detection approach for children with autism spectrum disorder (ASD) to be used in social and assistive robot inter- vention. Electrodermal activity (EDA) and blood volume pulse (BVP) signals are collected with an E4 smart wristband from children with ASD in different countries. The peak count and signal amplitude features are derived from EDA signal and used in order to detect...
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Noise effect on parameters of quiet sonar with code modulation
PublikacjaEarlier publications of the paper authors have shown that the use of code keying mixed with the CW FM sound signal allows the significant reduction in the distance measurement error, compared to classic silent CW FM sonar. In addition to the code modulation parameters, the magnitude of this error is influenced by the received input acoustic noise. The article shows the dependence of the input signal-to-noise ratio and the sound...
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Optimal configuration of an electrode array for measuring ventricles' contraction
PublikacjaAn influence of an electrode-array configuration on an impedance signal composition for a fixed spatial distribution of its sources is examined in the paper. The Finite Element Method and Geselowitz relationship were used for examining three different electrode-arrays. A sensitivity approach was used to evaluate each configuration assuming that localization of the signal source is known. A conductivity change, thus the source of...
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A wireless network for off-shore marine research
PublikacjaThis paper presents functionality, the most important technology developments and potential use cases of digital communication system, developed to facilitate selected tasks commonly required during off-shore operations and marine research, including: broadband information sharing between platforms isolated from an on-shore communication infrastructure, acquisition of large data-sets from variety of off-shore...
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Synchronization system for underwater acoustic communications using in shallow waters
PublikacjaA reliable synchronization system of the transmitted data frame has a significant impact on the efficiency of the underwater communication system. This applies in particular to communication systems dedicated to work in shallow waters, where the phenomenon of multipath permanently occurs. To overcome these difficulties, the concept of a synchronization system consisting of two broadband signals of opposite monotonicity was presented....
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DWUKIERUNKOWY PRZEWODOWY SYSTEM TRANSMISJI MOWY PRZY WYKORZYSTANIU TECHNOLOGII BPL
PublikacjaMonitorowanie pracowników w środowisku podziemnym jest niezwykle ważnym zadaniem. Z uwagi na możliwe zagrożenia, konieczne jest opracowanie niezawodnego systemu komunikacji głosowej pomiędzy personelem a przełożonym. Dzięki wysokiej odporności na uszkodzenia mechaniczne, kable zasilające pracujące w technice BPL (Broadband over Power Line) wydają się doskonałym rozwiązaniem. W pracy przedstawiono w pełni funkcjonalny dwukierunkowy...
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Investigating Feature Spaces for Isolated Word Recognition
PublikacjaThe study addresses the issues related to the appropriateness of a two-dimensional representation of speech signal for speech recognition tasks based on deep learning techniques. The approach combines Convolutional Neural Networks (CNNs) and time-frequency signal representation converted to the investigated feature spaces. In particular, waveforms and fractal dimension features of the signal were chosen for the time domain, and...
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A method of RTS noise identification in noise signals of semiconductor devices in the time domain
PublikacjaIn the paper a new method of Random Telegraph Signal (RTS) noise identification is presented. The method is based on a standardized histogram of instantaneous noise values and processing by Gram-Charlier series. To find a device generating RTS noise by the presented method one should count the number of significant coefficients of the Gram-Charlier series. This would allow to recognize the type of noise. There is always one (first)...
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Identification of Optocoupler Devices with RTS Noise
PublikacjaThe results of noise measurements in low frequency range for CNY 17 type optocouplers are presented. The research were carried out on devices with different values of Current Transfer Ratio (CTR). The methods for identification of Random Telegraph Signal (RTS) in noise signal of optocouplers were proposed. It was found that the Noise Scattering Pattern method (NSP method) enables to identify RTS noise as non-Gaussian component...
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APPLICATION OF STATISTICAL FEATURES AND MULTILAYER NEURAL NETWORK TO AUTOMATIC DIAGNOSIS OF ARRHYTHMIA BY ECG SIGNALS
PublikacjaAbnormal electrical activity of heart can produce a cardiac arrhythmia. The electrocardiogram (ECG) is a non-invasive technique which is used as a diagnostic tool for cardiac diseases. Non-stationarity and irregu- larity of heartbeat signal imposes many difficulties to clinicians (e.g., in the case of myocardial infarction arrhythmia). Fortunately, signal processing algorithms can expose hidden information within ECG signal contaminated...
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The development of an underwater telephone for digital communication purposes
PublikacjaThe underwater telephone HTL-10 has been designed to provide voice and data communication between helicopter and submarines using acoustic waves. It works in a half-duplex mode and uses analogue power-efficient modulation in the form of a single side-band, suppressed carrier, in a wide range of frequencies. It generates the transmitted signal, and processes the received signals. It is implemented with the use of digital signal...
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On the Application of Magnetoacoustic Emission for a Nondestructive Assessment of the Post Welding Heat Treatment of High Chromium Steel Weld Seams
PublikacjaThe paper analyses the possibility of post weld heat treatment (PWHT) quality assessment with the help of magnetoacoustic emission (MAE) signal measurements. Two welded superheater tubes, made of high chromium VM12 steel, were analysed—as welded and heat treated one. The analysed sample in the as welded state exhibited significantly higher hardness, accompanied by a big difference in the MAE signal intensity (of order of about...