Root Mean Square Voltage Research Articles

Evaluation of the metabolic changes during hemodialysis by signal averaged ECG.

Cardiovascular diseases are frequent complications of end-stage kidney disease. The aim of the present study was to prove the arrhythmogenic effect of dialysis using signal averaged ECG. The ECG changes and laboratory parameters (sodium, potassium, urea and creatinine levels) were detected during hemodialysis treatment in 26 patients suffering from end-stage kidney disease. The tests and the ECG were performed four times, before (0. minute), during (at 15 and 90 min), and eventually after dialysis (at 240 min). The duration of the QRS complex, high-frequency low-amplitude signals (HFLA), and root-mean-square voltage of the terminal 40 ms of the filtered QRS (RMS) were determined. We considered test results to be positive when two of the three tested parameters were outside the normal range: QRS > 120 ms, RMS < 20 uV, HFLA > 39 ms. Signal averaged ECG was positive in two cases (8%) before and after the dialysis. The duration of the QRS-complex increased significantly during the dialysis (predialysis: 109 +/- 7.6 ms, postdialysis: 116 +/- 8.0 ms, p < 0.0001). Serum urea nitrogen (predialysis: 26.2 +/- 5.4, postdialysis: 11.4 +/- 3.3 mmol/l, p <0.0001) and serum creatinine levels (predialysis: 931 +/- 212, postdialysis: 434 +/- 120 micromol/I, p < 0.0001) decreased significantly during the treatment. Significant and continuous decrease in the potassium levels were detected (predialysis: 5.30 +/- 0.72, postdialysis: 3.91 +/- 0.42 mmol/I, p < 0.0001) during the dialysis. Serum sodium levels (predialysis: 139 +/- 2.7, postdialysis: 141.4 +/- 2.2 mmol/I) had not changed during the dialysis. A significant negative correlation was found between decreasing potassium levels and increasing QRS duration (r = - 0.48, p = 0.01). Our results support our primer assumption that the metabolic changes during dialysis treatment can lead to considerable risk of cardiac arrhythmias.

Noise and interference in measured NMR images

This article describes the measurement and evaluation of noise and interference in experiments with nuclear magnetic resonance (NMR). Their presence in experimental results causes irreversible artefacts in measured images or errors in the calculated values of investigated quantities. Noise in the signal also reduces the sensitivity of the measuring instrument. From the point of view of results, there is no significant difference between noise and interference. Both signals are multi-frequency or have a changing frequency, meaning that they must be characterised using their power or root mean square (RMS) values of voltage or current. The RMS voltage at the output of the NMR receiver with a receive coil in its input was measured using an NMR console and compared to thermal noise voltages of known sources, e.g. resistors with known resistivity in the input of their receiver. The comparison indicates the possible inherence of interference. The noise measurement using the console was performed in two ways: using an acquisition only and using a complete measuring NMR sequence, which resulted in an image. The results served to test the quality of the hardware used for NMR experiments. It has been proven that the presented method is suitable for testing and improving the signal-to-noise ratio of NMR scanners without the need for the accumulation of seldom-used expensive instrumentation.

Reduction of EEG artifacts in simultaneous EEG-fMRI: Reference layer adaptive filtering (RLAF).

Although simultaneous measurement of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) is one of the most valuable methods for studying human brain activity non-invasively, it remains challenging to measure high quality EEG inside the MRI scanner. Recently, a new approach for minimizing residual MRI scanner artifacts in the EEG was presented: reference layer artifact subtraction (RLAS). Here, reference electrodes capture only the artifacts, which are subsequently subtracted from the measurement electrodes. With the present work we demonstrate that replacing the subtraction by adaptive filtering statistically significantly outperforms RLAS. Reference layer adaptive filtering (RLAF) attenuates the average artifact root-mean-square (RMS) voltage of the passive MRI scanner to 0.7 μV (-14.4 dB). RLAS achieves 0.78 μV (-13.5 dB). The combination of average artifact subtraction (AAS) and RLAF reduces the residual average gradient artifact RMS voltage to 2.3 μV (-49.2 dB). AAS alone achieves 5.7 μV (-39.0 dB). All measurements were conducted with an MRI phantom, as the reference layer cap available to us was a prototype.

Aging formula for lithium ion batteries with solid electrolyte interphase layer growth

Hybrid Electric Vehicle (HEV) current profiles are dynamic, consisting of repeated charge and discharge pulses. Accurate prediction of the battery response to these inputs requires models with open circuit voltage and Butler–Volmer kinetic nonlinearities. This paper derives a nonlinear, electrolyte-enhanced, single particle model (NESPM) that includes aging due to solid electrolyte interphase layer growth. The model is validated with experimental full charge, discharge, HEV cycle, and aging data from 4.5 Ah graphite/LiFePO4 cells. The NESPM is capable of operating up to 3C constant charge–discharge cycles and up to 25C and 10 s charge–discharge pulses within 35–65% state of charge (SOC) with less than 2% error. The NESPM aging model is then simplified to obtain explicit formulas for capacity fade and impedance rise that depend on the battery parameters and current input history. The formulas show that aging increases with SOC, operating temperature, time, and root mean square (RMS) current. The formula predicts that HEV current profiles with the (i) same average SOC, (ii) small SOC swing, (iii) same operating temperature, (iv) same cycle length, and (v) same RMS current, will have the same cell capacity fade.

A photointegrator of the molecular condensation nuclei detector

The problem of calculating the threshold sensitivity of an integrating photoreceiver (photocurrent integrator) is investigated. A noise model of a photointegrator is used to develop equivalent noise circuits and to calculate the RMS value of the voltage across the output of the photoreceiver. Among all the models of the real photointegrator it is conceivable that the approximation by an ideal photointegrator may be used. The threshold sensitivity of a photointegrator is defined as the power at the input of a photointegrator at which the root mean squared (RMS) voltage across its output is equal to the RMS voltage of total noise i.e. the signal-to-noise ratio is equal to one. A photomultiplier tube (PMT) can be used to increase the sensitivity. Formulas for calculating the sensitivity of a PMT-based photointegrator are given. The increase in sensitivity due to the use of PMT can be up to 18–30 times.An experimental study of a photometer of a molecular condensation nuclei (MCN) detector that forms a base of highly sensitive MCN gas analyzers was conducted. The measured sensitivity differed from the calculated by 10%. However, at femtowatt power levels it is very difficult to get rid of parasitic optical signals that are responsible for a small decrease in sensitivity compared to the theoretical prediction. In many practical applications, for example, for the X-ray absorption method of mineral extraction using position-sensitive photodiode X- ray receivers, an approximation of a real photointegrator must be used.

Transport of municipal wastewater, industrial and tributary discharges in eastern Lake Ontario and upper St. Lawrence River during the ice-free period of 2006

Abstract The surface transport of point and non-point source discharges into eastern Lake Ontario and upper St. Lawrence River was modeled as passive tracers using the Estuary and Lake Computer Model (ELCOM) during the ice-free period of 2006. Model hydrodynamics were validated against temperature and current observations and Lagrangian drifter tracks. Root-mean-square (RMS) errors of simulated temperature profiles were comparable to other model applications; however, current RMS errors and Fourier Norms were nominally larger than in open lake applications, and RMS errors for drifter tracks were 0.5–4.0 km (3 day duration). The errors in simulating currents and drifters, relative to temperatures, are likely the result of the difficulty in representing the complex geometry of the region, which is composed of numerous channels and islands. To determine the physical processes responsible for tracer transport, cross-correlation coefficients were calculated when model processes were switched off (e.g., wind forcing, surface thermodynamics, Earth rotation, St. Lawrence River outflow, etc.). Wind was found to be the most dominant process forcing transport of tracers both in the Kingston Basin and the St. Lawrence River, whereas the St. Lawrence River outflow, controlled by the Moses Saunders Dam, was found to influence the transport of tracers along the river. Tracers were transported ~ 60 km eastward under moderate to strong winds (> 5 ms − 1 ), remained nearshore when constrained within channels or by islands and had minimum dilutions of 20% and 39% at the Kingston Central and Kingston West drinking water intakes, respectively. The results suggest that factors such as the proximity between intakes and outfalls and presence of flow constraining topography, should be considered in future source and wastewater planning.

Performance Verification of Power Quality Signals Classification System

Power quality has become a greater concern nowadays. The increasing number of power electronics equipment contributes to the poor quality of electrical power supply. The power quality signals will affect manufacturing process, malfunction of equipment and economic losses. This paper presents the verification analysis of power quality signals classification system. The developed system is based on linear time-frequency distribution (TFD) which is spectrogram that represents the signals jointly in time-frequency representation (TFR). The TFD is very appropriate to analyze power quality signals that have magnitude and frequency variations. Parameters of the signal such as root mean square (RMS) and fundamental RMS, total waveform distortion (TWD), total harmonic distortion (THD) and total non-harmonic distortion (TnHD) of voltage signal are estimated from the TFR to identify the characteristics of the signal. Then, the signal characteristics are used as input for signal classifier to classify power quality signals. In addition, standard power line measurements are also calculated from voltage and current such as RMS and fundamental RMS voltage and current, real power, apparent power, reactive power, frequency and power factor. The power quality signals focused are swell, sag, interruption, harmonic, interharmonic, and transient based on IEEE Std. 1159-2009. The power quality analysis has been tested using a set of data and the results show that, the spectrogram gives high accuracy measurement of signal characteristics. However, the system offers lower accuracy compare to simulation due to the limitation of the system.

Development of a Transducer Power Control System for Ultrasonic Cleaning System

The goal of this paper is to implement a systematic controller for transducer power used in an ultrasonic cleaning system to save its consumption power in changing objects to be cleaned. To estimate and observe the current which is produced from the generator, root-mean-square (RMS) values of current signals in the transducer circuit are processed to produce moving average and moving standard deviation values by sliding a window for the most recent data. In this paper, we propose the controller scheme which is implemented with a digital signal processing (DSP) board based on the digital signal controller (DSC) chip to control the transducer power through digital proportional-integral (PI) controller and also applied to a commercial ultrasonic cleaning system for validation under change of cleaning load. The overshoot and undershoot of the current RMS have been decreased by 52.2% and 70.7%, respectively, with faster recovery to the initial current level by the proposed control system.

Pulse-Bias Electronics and Techniques for a Josephson Arbitrary Waveform Synthesizer

The Josephson arbitrary waveform synthesizer (JAWS) is a series array of thousands of superconducting Josephson junctions that are biased by current pulses such that the array produces voltage waveforms with quantum accuracy. Intrinsically accurate voltage waveforms synthesized with the quantized pulses from Josephson junctions were first demonstrated in 1996. Ten years later, a commercial ac standard was calibrated at an output root-mean-square (RMS) amplitude of 100 mV with the first practical superconducting digital-to-analog converter. Since then, many different bias techniques, pulse-drive electronics, and device technology have been developed and improved in order to achieve a maximum of 138 mV output RMS voltage per Josephson array. In this paper, we report new bias electronics and demonstrate two new pulse-bias techniques. The first technique has demonstrated 250 mV output RMS voltage per 6400-junction array and may enable a practical 1 V system with only four arrays. The second bias technique reduces inductance-related error signals at the signal frequency and should reduce systematic errors for waveforms with frequencies greater than 1 MHz.

Analysis of quasi-square-wave operation of DAB DC–DC converter

This work makes a novel contribution to the analysis of quasi-square-wave operation of dual-active bridge (DAB) converter by deriving equations for root mean square (RMS) and average device currents and RMS and peak inductor/transformer currents – these equations are useful in predicting device and passive component losses. Quasi-square-wave operation of the DAB converter is verified through Saber simulations and experimentation, validating the mathematical analysis. It is observed that quasi-square-wave mode improves average power transfer and the converter efficiency besides enhancing its soft-switching region without introducing additional passive components. The effect of quasi-square-wave on RMS and peak currents of devices and transformer/inductor is also discussed.

Influence of Transformer Capacity on Insulator Leakage Current Acquisition Results

To study the influence of test transformer capacity on insulator leakage current acquisition results, leakage current acquisition experiments with the clean and dry insulator and the water drops attached insulator were conducted based on the sampling resistor method and the test transformers of different capacities whose models are YDTW-1200 kVA/300 kV, YDTW-50 kVA/250 kV, YDTW-10 kVA/100 kV, YDJ-5 kVA/50 kV respectively. To make the results more reliable, sampling resistors with different resistances, 10 Ω, 100 Ω, and 1 kΩ, were used to collect the leakage current. The root-mean-square (RMS) values of the leakage current, the ratio of the 3rd harmonic to the fundamental (K3) and the 5th harmonic to the fundamental (K5) were extracted from the measured data. And it was discovered that the transformer capacities has a very slight influence on the leakage current RMS value but has a great impact on the value of K3 and the K5. The maximum K3 are approximately 3 times of the minimum K3 and the maximum K5 are approximately 9 times of the minimum K5.

Multiple vs. single harmonics AC-driven atmospheric plasma jet

In this paper, we report a comparison between the most commonly used single harmonics (sine voltage waveform) and the original multiple harmonics AC-driven atmospheric-pressure plasma jet. The designed multiple harmonics source was applied to a single-electrode plasma jet. In this research, we characterized and studied the advantages of a single-electrode jet which was powered with multiple harmonics voltage waves, fundamental frequency was varied between 5 and 60 kHz. Optical emission spectroscopy, electric probes and plasma jet visible length measurements lead to the conclusion that the optical emission intensity of emitting plasma species correlates with the discharge current RMS (Root Mean Square), whereas the jet visible length correlates with the electrode discharge voltage amplitude. These properties of the plasma jet cannot be obtained with single harmonics AC-driven plasma jets.

Position Servo Control of the Transverse Flux Machine Based on an Armature Current RMS and Initial Phase Control Method

A control method for position servo control of Transverse flux machine (TFM) by controlling armature current Root-Mean-Square (RMS) and initial phase is proposed in this paper. Specifically, the voltage balance equation of TFM is provided, and the phasor diagrams are analyzed to achieve the expression of electromagnetic power of TFM. The expression indicates that the electromagnetic torque is determined by armature current RMS and the initial phase. A position servo control system of TFM is established based on the expression. The results of the position servo control curves show that the position servo control system of TFM is effective.

Electromyography and high-speed elbow flexor exercise

Our study assessed motor unit behavior and muscle function from high-speed unilateral elbow flexor workouts. Electromyography and performance data were obtained from subjects who completed three workouts on an Impulse (Impulse Training Systems; Newnan, GA) exercise machine. Comprised of both tonic and phasic repetitions, workouts were done with three different loads (1.13, 3.4 and 6.8 kg) added to the machine. Electromyography was measured from three muscles (biceps brachii, triceps brachii, brachioradialis). Dependent variable means, obtained as the elbow flexed and extended, were compared with 2 (tonic, phasic) x2 (men, women) x3 (1.13, 3.4 and 6.8 kg) ANOVAs, with repeated measures for repetition and load. Bonferroni's adjustment preserved family-wise error rates and t-tests served as a post-hoc. With α = 0.05, several dependent variables displayed intra-repetition and -load effects. However triceps root mean square (RMS) values displayed repetition x load interactionsforboth elbowflexion andextension. Thetriceps, an elbowflexionantagonist, may actas animportant joint stabilizer, particularly at faster velocities and more extended joint angles. Unlike isometric or standard low-velocity paradigms performed against heavy loads, high-speed exercise may entail a more equitable distribution among factors (motor unit recruitment, rate coding, reflex potentiation, antagonist co-contraction) responsible for current triceps RMS values.

NEW ADAPTIVE METHOD FOR VOLTAGE SAG AND SWELL DETECTION

This paper presents an adaptive recursive least squares algorithm (ARLS) for detecting voltage sag and voltage swell events in power systems. Different methods have been developed to detect voltage sag and voltage swell. Some of them use window techniques, which are too slow when voltage sag or swell mitigation is required. Others depend on the extraction of a single non-stationary sinusoidal signal out of a given multi-components input signal, and therefore they don't consider the harmonic components in calculating the voltage root mean square value (rms). The method, proposed in this paper, is capable of estimating the voltage rms taking into account all harmonic components. The method is tested by applying it to different, simulated signals using ATP program, and compared with voltage sag detection algorithms.

Performance Comparison of Advanced Techniques for Voltage Dip Detection

Different aspects have to be considered when dealing with voltage dips in electric power systems. As a consequence, according to different needs arising from specific applications, different approaches have been proposed in the literature for the detection and classification of these events. This paper focuses on issues that are critical for the development of real-time compensation systems, namely, the capability of detecting correctly and rapidly the event while avoiding false alarms, and the algorithm complexity. To this purpose, approaches based on voltage root mean square, wavelets, Kalman filtering, peak voltage, missing voltage, and generalized likelihood ratio test are compared by means of computer simulations, by considering different kinds of voltage dips and by taking into account the uncertainty introduced by noise. The results provide meaningful indication on the choice of the most suitable method to be used in the considered applications.

Design and charge injection characteristics of an electrostatic dielectric liquid pulsed atomizer

Abstract An automotive fuel injector has been retrofitted with novel electrostatic components in order to improve the primary atomization and dispersion characteristics of the device. A specific design variant is presented and discussed outlining how a conventional fuel injector may be modified to house electrostatic components. With 2 bar gauge injection pressure and an electrical power of 2 mW, the injector can successfully supply intermittently charged fuel, containing spray specific charge levels up to ∼1.4 C/m 3 . Root mean square (RMS) spray specific charge and RMS total current vs. voltage curves are presented as a function of voltage pulse and solenoid valve frequencies for both low and high flow-rate operation. The fuel injector was able to operate in a stable manner at pulse train frequencies up to 20 Hz and the charge injection mechanism was identical to previous steady voltage and pulsed voltage steady flow systems. An optimal synchronization between the high voltage (HV) pulse frequency and solenoid valve frequency has been determined, allowing for the prevention of electrical breakdown events within the inter-electrode gap over a negative voltage ranging from 0 to 4.5 kV.

Generalized Likelihood Ratio Test for Voltage Dip Detection

An alternative detection algorithm, based on the generalized likelihood ratio test (GLRT), is proposed for the detection of voltage dips in power systems. The proposed method is compared to the classical approaches based on the voltage root mean square. It is shown that the GLRT may provide competitive performance in terms of capability of correctly detecting the dip starting instant. A DSP-based experimental setup for the implementation of the method is also presented.

Induced electromagnetic stirring behavior in a resistance spot weld nugget

A multi-physics hybrid numerical model, which couples electric, magnetic, thermal and flow fields, was used to investigate electromagnetic stirring behavior in a resistance spot weld nugget. The differences of two kinds of different excitation inputs, i.e., a sinusoidal current and its root-mean-square (RMS) value, were studied to examine if they could produce equivalent electromagnetic stirring effects in the weld nugget. Research showed that the two types of current inputs could produce almost identical fluid flow and heat transfer patterns and consistent evolution of flow and thermal fields in the nugget. At the end of the welding cycles, the maximum flow velocity and temperature between the two inputs differed by 11.6% and 0.3%, respectively. Therefore, the RMS current can be assumed to produce an approximately equivalent electromagnetic stirring effect with the sinusoidal current, and can be used in the future research to greatly improve the solution efficiency of the electromagnetic stirring behavior in the resistance spot weld nugget.

The Disparities in the Electrogram Voltage Measurement During Atrial Fibrillation and Sinus Rhythm

The peak electrogram voltage is a typical metric applied at each site for voltage mapping. However, the peak amplitude depends on the direction and complexity of the wavefront propagation. The root-mean-square (RMS) measure of the amplitude is a temporal integral that represents the steady-state value. The objective of this study was to investigate the disparities between the electrogram voltage during SR and AF by using 2 recording modalities: the conventional peak voltage and an RMS measurement. This study enrolled 20 patients (age = 59 +/- 13) with paroxysmal AF undergoing catheter ablation guided by Ensite array. The unipolar electrogram voltage during SR and AF (7 seconds in duration) was obtained from the same sites, and labeled by the 3-dimensional (3D) geometry. Overall 1,200 electrograms were analyzed from equally distributed mapping sites in the left atrium. A point-by-point comparison of the unipolar peak negative voltage (PNV) showed less agreement (Bland and Altman test: 10.4% outside 2 standard deviations, and intraclass correlation coefficient [ICC]= 0.64). The RMS voltage demonstrated agreement between SR and AF for all sites (BA test: 5.9% of the sites, and the ICC = 0.81). The probability of predicting a low-voltage during AF using the voltage during SR was significantly lower when using the PNV measurement compared to that when using the RMS voltage (15% vs 61%, P < 0.05). The peak electrogram unipolar voltage during AF did not represent the voltage during SR. The RMS amplitude may be an alternative metric for voltage mapping to characterize the myocardial substrate.