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Journal articles on the topic 'EMF method'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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1

Wei, Kai Xia. "Numerical Solution for Weight Function of Electromagnetic Flowmeter Using Finite Element Method." Applied Mechanics and Materials 444-445 (October 2013): 1360–63. http://dx.doi.org/10.4028/www.scientific.net/amm.444-445.1360.

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Weight function is related with the sensor structure of electromagnetic flowmeter (EMF). Because of complex boundary conditions, it is difficult to solve the voltage differentiation equation of EMF directly to get weight function. The finite element numerical analysis method is tried to solve the weight function for the point and large-electrode EMF in this paper. The results prove it is feasible and efficient to obtain weight function of EMA by means of finite element numerical analysis.

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2

Migault, Lucile, Ronan Garlantezec, Clément Piel, Laetitia Marchand-Martin, Sébastien Orazio, Marie Cheminat, Cécile Zaros, et al. "O1B.6 Maternal cumulative exposure to extremely low frequency electromagnetic fields, prematurity and bith weight: a pooled analysis of two birth cohorts." Occupational and Environmental Medicine 76, Suppl 1 (April 2019): A6.2—A6. http://dx.doi.org/10.1136/oem-2019-epi.17.

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BackgroundData on the effects of extremely low frequency electromagnetic fields (ELF-EMF) on pregnancy outcomes are inconclusive.ObjectivesTo study the relation between maternal cumulative exposure to ELF-EMF during pregnancy and the risk of prematurity or small for gestational age in a pooled analysis of two French birth cohorts.MethodsElfe and Epipage2 are both population-based birth cohorts initiated in 2011 and included 18 329 and 8400 births respectively. Health data and household, mother and child characteristics were obtained from medical records, by face-to-face interview at maternity, and completed during follow-up. A recently updated job-exposure-matrix (JEM) was used to assess cumulative exposure to ELF-EMF during three periods: 1) until 15, 2) until 28 and 3) until 32 weeks of gestation. Analyses were restricted to single live births in mainland France and to mothers with documented jobs (n=19,894). Differences in selection frame between the two cohorts were controlled using a propensity score weighting method. We used multiple imputation method to deal with missing data. Logistic regression models adjusted for the main potential confounders were used.ResultsAccording to the period studied, 3.2% to 4% of mothers were classified as highly exposed to ELF-EMF. An increased risk of spontaneous prematurity was observed among the most exposed groups in period 2 and period 3. Overall, no consistent association with small for gestational age was found.ConclusionThis study, with substantial statistical power provides evidence of a possible association between cumulative exposure to ELF-EMF during pregnancy and the risk of spontaneous prematurity.

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Abdimuratov, Zh S., Zh D. Manbetova, M. N. Imankul, K. S. Chezhimbayeva, and A. Zh Sagyndikova. "METHODS FOR PROTECTING THE EQUIPMENT OF CELLULAR (MOBILE) CONNECTION FROM ELECTROMAGNETIC IMPACT." PHYSICO-MATHEMATICAL SERIES 335, no. 1 (February 10, 2021): 81–89. http://dx.doi.org/10.32014/2021.2224-5294.12.

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Under electromagnetic impact (EMI) of a sufficient level, temporary disruption of functioning, processing, transmission and storage of information in cellular equipment is possible. Possible problems of electromagnetic compatibility (EMC) of a mobile phone and a base station (BS) of cellular connection under the influence of electromagnetic radiation (EMR) from other sources and their negative impact on functioning are considered. The energy of the HF electromagnetic field (EMF) after passing through the protective case can affect the devices of shielded radio electronic equipment (REE), therefore, the possible negative consequences of the impact of high-energy EMF on the REE are described. Possible negative consequences under certain conditions from the influence of the skin-effect, the effects of electrostatic discharge and electromagnetic pulses on electronic devices are given. It is shown that the constructional method of protecting REE from the effects of external electromagnetic factors consists in reducing the collected and transmitted EMF energy by improving the design, placement and installation of equipment. Components of some vendors for 5G systems that are resistant to external interference are given, and the possibilities for reducing the radiation level of a cell phone are noted. The necessity of an integrated approach to solving EMC problems is substantiated, which consists in the use of structural, circuitry and structural-functional methods of EMC provision. The new 5G (Fifth Generation) standard will operate at higher operating frequencies compared to previous generations. Due to the workload of the electromagnetic spectrum at frequencies below 6 GHz, 5G networks will be based on wireless radio access systems operating at frequencies of 30–100 GHz, that is, in the lower band of the extremely high frequency range EHF (Extremely High Frequency), 30–300 GHz.

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Abdimuratov, Zh S., Zh D. Manbetova, M. N. Imankul, K. S. Chezhimbayeva, and A. Zh Sagyndikova. "METHODS FOR PROTECTING THE EQUIPMENT OF CELLULAR (MOBILE) CONNECTION FROM ELECTROMAGNETIC IMPACT." PHYSICO-MATHEMATICAL SERIES 335, no. 1 (February 8, 2021): 81–89. http://dx.doi.org/10.32014/2021.2518-1726.12.

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Under electromagnetic impact (EMI) of a sufficient level, temporary disruption of functioning, processing, transmission and storage of information in cellular equipment is possible. Possible problems of electromagnetic compatibility (EMC) of a mobile phone and a base station (BS) of cellular connection under the influence of electromagnetic radiation (EMR) from other sources and their negative impact on functioning are considered. The energy of the HF electromagnetic field (EMF) after passing through the protective case can affect the devices of shielded radio electronic equipment (REE), therefore, the possible negative consequences of the impact of high-energy EMF on the REE are described. Possible negative consequences under certain conditions from the influence of the skin-effect, the effects of electrostatic discharge and electromagnetic pulses on electronic devices are given. It is shown that the constructional method of protecting REE from the effects of external electromagnetic factors consists in reducing the collected and transmitted EMF energy by improving the design, placement and installation of equipment. Components of some vendors for 5G systems that are resistant to external interference are given, and the possibilities for reducing the radiation level of a cell phone are noted. The necessity of an integrated approach to solving EMC problems is substantiated, which consists in the use of structural, circuitry and structural-functional methods of EMC provision. The new 5G (Fifth Generation) standard will operate at higher operating frequencies compared to previous generations. Due to the workload of the electromagnetic spectrum at frequencies below 6 GHz, 5G networks will be based on wireless radio access systems operating at frequencies of 30–100 GHz, that is, in the lower band of the extremely high frequency range EHF (Extremely High Frequency), 30–300 GHz.

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5

Almarhoon, Ali, Yuan Ren, and Z. Q. Zhu. "Influence of back-EMF and current harmonics on sensorless control performance of single and dual three-phase permanent magnet synchronous machines." COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 35, no. 2 (March 7, 2016): 744–63. http://dx.doi.org/10.1108/compel-12-2015-0441.

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Purpose – The purpose of this paper is to investigate the influence of back-EMF and current harmonics on position and speed estimation accuracy for single and dual three-phase (DTP) permanent magnet synchronous machines (PMSMs) with two fundamental-model-based sensorless control strategies which are widely utilized for AC machines, i.e. flux-linkage observer (FO) and simplified extended Kalman filter (EKF). Design/methodology/approach – The effect of distorted back-EMF is studied for sensorless vector control of single three-phase PMSM. For the influence of current harmonics, unlike the existing literature where the current harmonics are deliberately injected, in this paper, sensorless switching-table-based direct torque control (ST-DTC) strategies for DTP-PMSM which inherently suffer from non-sinusoidal stator currents in addition to the distorted back-EMF, are investigated experimentally. Findings – By employing the FO and simplified EKF-based sensorless vector control of single three-phase PMSM, it can be concluded that the rotor position estimation accuracy is less affected by the back-EMF harmonics when the simplified EKF method is utilized since it is less sensitive to such noises. When the influence of non-sinusoidal stator currents together with back-EMF harmonics is investigated for the conventional and modified ST-DTC of DTP-PMSM, it is indicated that the simplified EKF exhibits better position and speed estimation accuracy in both the conventional and modified ST-DTC strategies. In addition, its steady-state performance shows a slight superiority over that based on FO, in terms of flux and torque ripples, and THD of phase currents. For the dynamic performance, the estimated speed of simplified EKF shows less phase lag and fluctuations compared to that of FO. Originality/value – This paper introduces the influence of back-EMF and current harmonics on sensorless control performance for single and DTP PMSMs. Detailed experimental results show that the simplified EKF exhibits better rotor position and speed estimation accuracy compared to that of FO due to its higher noise-rejection ability.

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6

Li, Zi Cheng, Zi Yu Ou, and Shan Mei Cheng. "Rotor Position Phase Correction for Sensorless Brushless DC Motor Based on Line Back EMF." Advanced Materials Research 347-353 (October 2011): 607–10. http://dx.doi.org/10.4028/www.scientific.net/amr.347-353.607.

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This paper proposes a novel rotor position estimation method based on line back EMF for brushless DC motor (BLDCM). The relationship between position phase error and the symmetric line back EMF is analyzed. It is noted that line back EMF error can exactly reflect rotor position phase error. If the amplitude of line back EMF at the beginning of commutation is equal to the amplitude of line back EMF at the end of commutation, the waveform of line back EMF should be symmetric. Based on the above analysis, a closed loop control method to correct rotor position phase is presented. Line back EMF error is employed to keep the waveform of line back EMF symmetrical by PI controller. This paper also develops a sensorless BLDCM driver to implement the proposed method based on DSP and the experimental results prove the validity of the proposed method.

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7

Thakur, Anant. "Improvement of Back EMF & Minimization of Torque Ripple of BLDC Motor." SMART MOVES JOURNAL IJOSCIENCE 5, no. 8 (August 6, 2019): 1–7. http://dx.doi.org/10.24113/ijoscience.v5i8.220.

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In Brushless DC (BLDC) motor minimized the torque ripple with the help of electronically based commutators. When torque ripple is minimizes then copper loss is also minimizes. In this paper, our main aspect to decrease the torque ripples & improved the back emf of brushless dc (BLDC) motor. This paper shows that the torque produced by the BLDC motors with trapezoidal Back EMF is constant under ideal condition. Due to freewheeling torque ripples are produced which is reduced. In this paper rotor position is determined by the Zero Crossing Detection (ZCD) of back emf. Unlike old methods of calculating Back emf of the BLDC by creating a virtual neutral point, a complimentary method is used. This method provides a wide range of speed. A pre conditioning circuit is proposed to rectify the back emf at very low speed. The rotor position can be determined even in stand still condition to minimize the torque ripple and designed to overcome the disadvantages from other torque ripple decrease methods.

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8

Wei, Kai Xia, Shu Long Gu, and Long Qing He. "Solving Weight Function for the Partially Filled Pipe Electromagnetic Flowmeter by Means of Finite Element Numerical Analysis." Advanced Materials Research 550-553 (July 2012): 3395–99. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.3395.

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The weight function method that uses a known weight function has been a general tool for the signal analysis of the electromagnetic flowmeter(EMF). However, it is difficult to solve the voltage equation directly by analytical method in order to get weight function for the partially filled pipe electromagnetic flowmeter(EMF-PF). The finite element numerical analysis method is tried to solve the weight function for the EMF-PF in this paper. The results show that weight function for EMF-PF relates to fill height of liquid in partially filled pipes, and there is a nonlinear function relationship between weight function for EMF-PF and fullness degree of liquid in the pipe.

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9

Lider, Andrey M., Vitalii V. Larionov, and Maxim S. Syrtanov. "Hydrogen Concentration Measurements at Titanium Layers by Means of Thermo-EMF." Key Engineering Materials 683 (February 2016): 199–202. http://dx.doi.org/10.4028/www.scientific.net/kem.683.199.

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The thermo-emf and electrical resistivity of hydrogenated titanium were measured. Hydrogen concentration in titanium varies from 0.005 to 0.25%. We have compared the methods regarding their sensitivity to the alteration of thermo-emf and electrical resistivity during titanium hydrogenation. The accuracy of the obtained results was verified by comparing them with the results for palladium. It was demonstrated that the method implementing thermo-emf is sensitive to hydrogen concentration in titanium at different depth of the alloy. On the basis of performed measurements, we have proposed a graphical method for detecting the change in titanium structure.

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10

Jesus, Luiz Henrique Reis de, Geyverson Teixeira de Paula, and Leonardo da Cunha Brito. "On-load Back-EMF Optimization Based on the Back-EMF MST Method and Parametric Optimization." Journal of Microwaves, Optoelectronics and Electromagnetic Applications 18, no. 3 (July 2019): 358–76. http://dx.doi.org/10.1590/2179-10742019v18i31511.

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11

Zhao, Ying, and Yong Jun Yang. "Modeling and Simulation of Brushless DC Motor with Nonideal Back EMF." Applied Mechanics and Materials 130-134 (October 2011): 3434–37. http://dx.doi.org/10.4028/www.scientific.net/amm.130-134.3434.

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The back electromotive force (EMF) waveform of brushless dc motor (BLDCM) is trapezoid. But it is not absolutely trapezoid because of motor manufacturing. In this paper, a method of modeling for BLDCM with nonideal back EMF is presented. Eighteen states during an electric angle cycle are obtained after the nonideal back EMF of BLDCM is analyzed. The S-Function of MATLAB is used to generate the nonideal back EMF according to rotor speed and position. The pulse width modulation (PWM) current control of BLDCM is adopted. Simulated results validate the method.

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12

Mansimova, S. H. Mansimova. "THERMODYNAMIC INVESTIGATION OF THE PbTe–AgSbTe2 SYSTEM BY MEANS OF EMF METHOD." Azerbaijan Chemical Journal, no. 3 (October 10, 2019): 41–47. http://dx.doi.org/10.32737/0005-2531-2019-3-41-47.

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13

Bryukhan, Fedor, and Mariya Amirkhanyan. "Technogenic electromagnetic impact zones of electric grid facilities." MATEC Web of Conferences 193 (2018): 02017. http://dx.doi.org/10.1051/matecconf/201819302017.

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Introduction of technogenic physical fields including electromagnetic fields (EMF) to the environment can have an adverse impact on both humans and environment. Development of safety tools protecting against EMF impact involves studying their intensity and assessing EMF spatial extent. This paper proposes a definition of an EMF technogenic impact zone (TIZ) concept based on the instruments lower sensitivity threshold. The paper gives the results of EMF TIZ width assessment based on the measurements of EMF electric and magnetic components intensity generated by power line communication (PLC) along its 200-meter section. The EMF TIZ width was found to be homogeneous along the PLC section. It is noted that the proposed interpretation of EMF TIZ and method of its determination can be generalized for other EMF sources as well, for example, for SHF-radiation sources, tele-and radio-transmission facilities, mobile communication antennas, etc.

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14

Qi, Zhao, Shen Xing-Quan, Yu Da-Guo, and Yuan Bin. "The Research of EMF Zero-crossing Detection Method." Procedia Engineering 15 (2011): 2474–78. http://dx.doi.org/10.1016/j.proeng.2011.08.465.

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15

Otobe, H., M. Akabori, and Y. Arai. "Oxygen potential measurements of Cm0.09Pu0.91O2−xby EMF method." IOP Conference Series: Materials Science and Engineering 9 (March 1, 2010): 012015. http://dx.doi.org/10.1088/1757-899x/9/1/012015.

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16

Ottøy, Magnar, Tormod Førland, Signe Kjelstrup Ratkje, and Steffen Møller-Holst. "Membrane transference numbers from a new emf method." Journal of Membrane Science 74, no. 1-2 (October 28, 1992): 1–8. http://dx.doi.org/10.1016/0376-7388(92)87067-8.

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17

Pankajavalli, R., and O. M. Sreedharan. "Thermodynamic stability of HfMo2O8 by the emf method." Journal of Nuclear Materials 175, no. 3 (December 1990): 194–96. http://dx.doi.org/10.1016/0022-3115(90)90206-3.

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18

Imamaliyeva, S. Z., I. F. Mehdiyeva, D. B. Taghiyev, and M. B. Babanly. "Thermodynamic investigations of the erbium tellurides by EMF method." Physics and Chemistry of Solid State 21, no. 2 (June 15, 2020): 312–18. http://dx.doi.org/10.15330/pcss.21.2.312-318.

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The work presents the results of a thermodynamic study of the Er-Te system by the method of electromotive forces (EMF) in the temperature range of 300-450 K. From the EMF measurements of the concentration cells relative to the Er and ErTe electrodes, the partial thermodynamic functions of ErTe and Er in the alloys are determined, based on which the standard thermodynamic formation functions and the standard entropies of the intermediate compounds ErTe3, Er2Te3, and ErTe are calculated. A comparative analysis of the obtained data with the literature is carried out.

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Stankevych, G., Yu Kovra, and A. Kats. "INFLUENCE OF ELECTROMAGNETIC FIELD OF EXTREMELY LOW FREQUENCIES ON HYGROSCOPIC PROPERTIES OF WHEAT GRAIN MASS." Grain Products and Mixed Fodder’s 21, no. 1 (September 8, 2021): 9–14. http://dx.doi.org/10.15673/gpmf.v21i1.2088.

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The research results of the influence of electromagnetic field (EMF) of extremely low frequencies (ELF) on hygroscopic properties of Shestopalivka wheat variety of 2019 harvest have been given. Grain processing was performed on the experimental stand that consisted of the polymeric cylindrical container for grain, solenoid coil, generator of electromagnetic waves GZ-112/1 and a power amplifier of low frequency. The output signal of generator was set in the form of sine wave and controlled by oscillograph C1-78. The studies were performed at EMF frequencies of 10, 16, 24 and 30 Hz. Magnetic induction of grain treatment was constant and equaled 10 mTl. The duration of grain processing was 6 minutes.The equilibrium moisture content of wheat grain was determined by the tensometric method at temperatures t 9 °C and 23 °C and relative humidity φ 33…36 % and 82…82.5 %. The necessary conditions of air were created in desiccators with solutions of sulfuric acid placed in thermostats and refrigerators.It has been determined that the equilibrium moisture of wheat grain processed by EMFof ELF – is in the range of 12.17…20.56 %, and unprocessed grain – in the range of 12.62…21.03 %. Regardless of the frequency of EMF, equilibrium moisture content of the grain wheat processed by EMF varies according to the known laws – decreases with temperature increase and increases with increasing of air relative humidity. It has been shown that the impact of processing by EMF of ELF on the equilibrium moisture contentof wheat grain is manifested at different frequencies in different ways, which is likely due to the resonance phenomena. It has been established that the processing of grain by EMF with frequencies of 10...30 Hz practically has no effect on the equilibrium moisture content of grain at 23 °C and a relative humidity of 33...82.5 % which remains practically at the level of the unprocessed grain. It has been shown that the processing of grain by EMF with frequencies of 24 and 30 Hz under conditions of t = 9 °C and φ = 33 % leads to higher equilibrium moisture content compared to unprocessed wheat grain from 14.45 % to 16.85...16.95 %. Processing of grain with frequencies of 10 and 16 Hz under the same conditions, on the contrary – leads to a decrease in the level of equilibrium moisture content to 13.74…13.86 %. Empirical coefficients have been determined and the equation has been proposed that describes the dependence of equilibrium moisture content of not processed and processed wheat grain by EMF with frequency 10...30 Hz on temperature and relative humidity of the ambient air.

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Nalli, Rajesh, K. Subbarao, M. Ramamoorthy, and M. Kiran Kumar. "A Novel Sensorless Controlling Technique of a 3-Phase Brushless DC Motor for Industrial Application." Journal of Computational and Theoretical Nanoscience 16, no. 12 (December 1, 2019): 5032–41. http://dx.doi.org/10.1166/jctn.2019.8560.

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This paper provides the novel sensorless control technique of a 3-phase BLDC motor. The introduction to the conventional sensorless techniques like Back emf detection, free-wheeling diode detection technique, back emf third harmonic detection techniques are discussed. Conventional sensorless technique has its drawbacks like high frequency noise, having more number of switches in free-wheeling diode detection method causes more switching losses. Wrong estimation rotor position in back emf zero detection technique where the floating phase back emf is consider for commutation estimation. In all the above discussed methods the back emf estimation is a speed dependent function, whereas in proposed controlling technique the flux linkage calculation is not a speed (ω) dependent function. So, that the accuracy of rotor position prediction will be better than conventional methods. The analysis of proposed technique is compared with conventional sensor based controlling techniques to validate the accuracy. The proposed technique implemented using MATLAB/SIMULINK software.

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Sheng, Guorui, Tiegang Gao, and Shun Zhang. "Detection of Content-Aware Image Resizing for Forensic Applications." International Journal of Digital Crime and Forensics 6, no. 2 (April 2014): 23–39. http://dx.doi.org/10.4018/ijdcf.2014040102.

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Seam-Carving is widely used for content-Aware image resizing. To cope with the digital image forgery caused by Seam-Carving, a new detecting algorithm based on Expanded Markov Feature (EMF) is presented. The algorithm takes full advantage of Transition Probability Matrix to represent correlation change caused by Seam-Carving operation. Different with traditional Markov features, the EMF not only reflects the change of correlation within the intra-DCT block, it also represents the change of correlation in more extensive range. The EMF is a fusion of traditional and expanded Markov Transition Probability Matrix. In the proposed algorithm, The EMF of normal image and that of forged image is trained by SVM, and thus the nornal image and forged image by Seam-Carving can be discriminated by SVM. The experimental result shows that the performance of proposed method is better than that of the method based on traditional Markov features and other existing methods

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22

Zhang, Hua Qiang, Xin Sheng Wang, and Fei Fei Wang. "An Improved Estimation Method of Permanent Magnet Synchronous Motor without Position Sensor." Advanced Materials Research 159 (December 2010): 616–21. http://dx.doi.org/10.4028/www.scientific.net/amr.159.616.

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On the basis of interior electromagnetism relationship and vector control principle, the vector control system of Permanent Magnet Synchronous Motor (PMSM) without position sensor is designed. There are two main identification methods are introduced to estimate the position and speed of PMSM. One scheme is based on the back Electromotive Force (EMF) and the other is Model Reference Adaptive Standard (MRAS). The former method achieves fast dynamic-state response while the later method obtains better steady-state performance. According to both of them advantages, an improved estimate method which combining the back EMF and the MARS is proposed. Simulation results show that the improved method is feasible and stable.

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Akay, Ali, and Paul Lefley. "Torque Ripple Reduction Method in a Multiphase PM Machine for No-Fault and Open-Circuit Fault-Tolerant Conditions." Energies 14, no. 9 (May 2, 2021): 2615. http://dx.doi.org/10.3390/en14092615.

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This paper presents a method that has been developed to reduce the torque ripples under healthy and open-circuit fault-tolerant (OCFT) conditions for a multiphase permanent magnet (PM) machine. For smooth torque, both the phase current and the back electromotive force (back-EMF) should be purely sinusoidal. To improve the torque in a multiphase machine, higher-order current harmonics are injected, which are related to the harmonics in the back-EMF. For this reason, generally, multiphase machines are designed with higher-order back-EMF harmonics. However, these harmonics produce ripples in the torque. In light of this, a torque ripple cancellation method has been developed that first determines an additional current component from the harmonic content of the back-EMF and then injects these additional components to cancel the torque ripple. It has been found that this new torque ripple cancellation method works for both faultless and faulty conditions in a five-phase PM machine. The method has been validated using Finite Element Analysis, and the results are presented in this paper.

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Orujlu, Elnur N., Ziya S. Aliev, Yasin I. Jafarov, Eldar I. Ahmadov, and Mahammad B. Babanly. "Thermodynamic study of manganese tellurides by the electromotive force method." Kondensirovannye sredy i mezhfaznye granitsy = Condensed Matter and Interphases 23, no. 2 (June 4, 2021): 273–81. http://dx.doi.org/10.17308/kcmf.2021.23/3438.

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The thermodynamic properties of manganese tellurides were determined using an electromotive force (EMF) method with a liquid electrolyte in a temperature range from 300 to 450 K. EMF measurements were performed using equilibrium samples taken from the two-phase regions, namely MnTe2 + Te and MnTe + MnTe2, of the Mn–Te system. The phase compositions of all samples were controlled with the X-ray diffraction (XRD) method. The partial molar functions of manganese in alloys, as well as the standard thermodynamic functions of the formation and standard entropies of MnTe and MnTe2, were calculated. A comparative analysis of obtained results with literature data is performed

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Singatulin, Roman S., and Alexandr V. Sapryka. "Experimental studies results of electromagnetic field effect of dielcometer system to increase the yield of greenhouse crops." E3S Web of Conferences 176 (2020): 03011. http://dx.doi.org/10.1051/e3sconf/202017603011.

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The article presents experimental studies of the application of electromagnetic technologies for impact on biological objects. Tomato seeds were chosen as experimental biological objects. For the study, the technological parameters of EMF were obtained using the method of full factor experiment. Laboratory and field studies were carried out. In laboratory studies, the results of EMF effects on chromosomal aberrations of tomato seeds were obtained. Dependencies of chromosomal aberrations in tomato seeds on changes in seeds EMF exposure, EMF frequency, and EMF power flow density were given. In field studies, pre-sowing treatment of tomato seeds with electromagnetic radiation was performed in order to cause changes in biochemical processes in the plant. During the experiment, 55 options of pre-sowing EMF treatment with specified parameters were obtained. Dependencies of tomato seed germination on input parameters - EMF frequency, power flow density and exposure were given. After laboratory and field tests, it was concluded that pre-sowing EMF treatment of tomato seeds with optimal parameters results in an increase in chromosomal aberrations of tomatoes by 5.5%; field germination of tomatoes by 18%.

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Bhambure, Mahesh Dattatraya. "Control System for BLDC Motor using Back EMF Method." International Journal for Research in Applied Science and Engineering Technology 7, no. 1 (January 31, 2019): 722–27. http://dx.doi.org/10.22214/ijraset.2019.1112.

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Aerts, Sam, Dirk Deschrijver, Luc Martens, Tom Dhaene, and Wout Joseph. "Sequential measurement method to construct RF-EMF exposure maps." ISEE Conference Abstracts 2013, no. 1 (September 19, 2013): 3088. http://dx.doi.org/10.1289/isee.2013.p-3-21-13.

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28

Otobe, Haruyoshi, Mitsuo Akabori, and Yasuo Arai. "Oxygen potential measurements of Am0.5Pu0.5O2−x by EMF method." Journal of Nuclear Materials 389, no. 1 (May 2009): 68–71. http://dx.doi.org/10.1016/j.jnucmat.2009.01.009.

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29

Mercer, David. "Scientific Method Discourses in the Construction of `EMF Science'." Social Studies of Science 32, no. 2 (April 2002): 205–33. http://dx.doi.org/10.1177/0306312702032002002.

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30

Katayama, I., N. Kemori, and W. T. Denholm. "Thermodynamic study of CaO-Sb2O3 system by emf method." Berichte der Bunsengesellschaft für physikalische Chemie 102, no. 9 (September 1998): 1272–74. http://dx.doi.org/10.1002/bbpc.19981020935.

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Wakiwaka, Hiroyuki, Hironobu Tsuji, Masami Nirei, Yoshinori Shinohara, Kouichi Ohkubo, and Hisaya Mizutani. "Consideration of emf calculation method on an electromagnetic tachometer." IEEJ Transactions on Sensors and Micromachines 117, no. 2 (1997): 80–83. http://dx.doi.org/10.1541/ieejsmas.117.80.

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Yu, Linxin, and Dazhi Wang. "A Hybrid Filtering Stage-Based Rotor Position Estimation Method of PMSM with Adaptive Parameter." Sensors 21, no. 14 (July 7, 2021): 4667. http://dx.doi.org/10.3390/s21144667.

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The performance of sensorless control in a permanent magnet synchronous machine (PMSM) highly depends on the accuracy of rotor position estimation. Owing to its strong robustness, phase-locked loop (PLL) is widely used in rotor position estimation. However, due to the influence of harmonics existing in back electromotive force (EMF), estimation error occurs by using PLL. In this paper, a hybrid filtering stage-based PLL is proposed to improve the rotor position estimation. Adaptive notch filters and moving average filters are integrated together to eliminate harmonic EMF. To make the method effective under varying speed conditions, adaptive parameters design guidelines are provided, considering dynamic performance under a wide operating range. The proposed method can accurately detect rotor position even under harmonic EMF disturbances. It can also adjust the frequency adaptively based on the rotating speed of the rotor, which means the estimation performance is not deteriorated under rotating speed changing conditions. The simulation results verify the effectiveness of the proposed method.

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Wang, Li Huo, Wei Yao, and Wei Zhang. "A Fridge Compressor Control System Based on MC56F8013." Advanced Materials Research 383-390 (November 2011): 6019–24. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.6019.

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This paper describes Freescale company’s DSP device MC56F8013 implementation of a fridge compressor control system about BLDC motors without position sensors, which includes motor starting and back EMF running. The motor start-up detects the variation of rotor position according to inductance of stator core. Then when the rotor is accelerated to a certain speed, EMF mode is switched. The EMF mode estimates the rotor position by back EMF zero-crossing detection method. The experiment results prove that the proposed system based on MC56F8013 can work normally and efficiently, and guarantee the demand of domestic refrigerator.

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Abdullayev, A. M., A. I. Zhukov, S. V. Maryokhin, and S. D. Riabchykov. "Engineering Margin in Calculations of Energy Release in VVER-1000 core." Nuclear and Radiation Safety, no. 2(78) (June 7, 2018): 20–26. http://dx.doi.org/10.32918/nrs.2018.2(78).03.

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A method for calculating the engineering margin factor (EMF) in calculations of the energy release in the core of VVER-1000 reactors is proposed in the paper. The analysis of various approaches in the calculation of EMF is carried out and various factors influencing EMF and the ways of their consideration —deterministic and statistical — are determined. The main attention is paid to the influence of gaps between the fuel assemblies on the energy release of fuel rods and the contribution of this factor to the EMF. The limitations and conservatism of two-dimensional small-scale calculations of the energy release of fuel rods in case of deviation of the gap size between the fuel assemblies from the design one are shown. A three-dimensional approach to calculating the contribution of gaps to the EMF is proposed. The approach is based on detailed measurements of the shape of fuel assemblies removed from the core performed at Zaporizhzhya NPP [13]; simulation of the distribution of gaps in the reactor core [16] using measurement data; two-dimensional calculations of the energy release of fuel rods in separate fuel assemblies, surrounded by gaps of different widths, with mirroring boundary conditions; three-dimensional calculations of energy release of fuel rods in fuel assemblies in the reactor core. Two-dimensional and three-dimensional calculations are performed by the wellknown ALPHA-H/PHOENIX-H/ANC-H codes. The proposed approach allows considering not only the change in the fuel rod power, particularly of the peripheral rods, which is inherent in the currently used methods of calculating EMF, but also takes into account the change in the power of the fuel assemblies in the core, which makes the proposed method more realistic and removes the excessive conservatism of EMF calculations and, thereby, allows improving fuel efficiency. For fuel assemblies produced by Westinghouse, it is proposed to use full EMF: for fuel rod power (FΔH) 1.111 and for fuel rod linear power (FQ) 1.173. The use of the BEACONTM monitoring system makes it possible to further reduce the EMF: for fuel rod power (FΔH) - up to 1.084 and for fuel rod linear power (FQ) - up to 1.121.

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Abba, Faiza, and M’hemed Rachek. "Time-Stepping FEM-Based Multi-Level Coupling of Magnetic Field–Electric Circuit and Mechanical Structural Deformation Models Dedicated to the Analysis of Electromagnetic Actuators." Actuators 8, no. 1 (March 1, 2019): 22. http://dx.doi.org/10.3390/act8010022.

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The present paper introduced a framework for multi-level coupling transient electromagnetic fields (EMF) and mechanical structural dynamics based on the finite element method (FEM). This framework was dedicated to predicting, with better accuracy, the wave magnetic force density for obtaining the mechanical deformation occurring in electromagnetic actuators (EMAs). The first-level EMF transient model coupling is related to the magnetic field equations that are strongly coupled with the electric circuit input voltage equations. This is done by considering the magnetic saturation through the Newton–Raphson (N–R) method. The time-stepping solution of the EMF model resulted in the magnetic force densities being computed from the Lorentz force (LZ) expressions, based on the space–time variation of the induced eddy current. For the second coupling level, the EMF model was sequentially coupled with the mechanical structural deformation equations (MDef) through the local magnetic force density to achieve minimal material dynamic displacement and deformation. The developed multi-physics EMF–MDef time-stepping (FEM) model tools were implemented using the Matlab software.

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Gao, Caixia, Yanjie Nie, Jikai Si, Ziyi Fu, and Haichao Feng. "Mode Recognition and Fault Positioning of Permanent Magnet Demagnetization for PMSM." Energies 12, no. 9 (April 30, 2019): 1644. http://dx.doi.org/10.3390/en12091644.

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This paper proposes a demagnetization fault detection, mode recognition, magnetic pole positioning, and degree evaluation method for permanent magnet synchronous motors. First, the analytical model of the single-coil no-load back electromotive force (EMF) of demagnetization fault for Permanent magnet synchronous motor (PMSM) arbitrary magnetic poles is established. In the analytical model, the single-coil no-load back EMF residual of the health state and the single magnetic pole sequential demagnetization fault are calculated and normalized. Model results are used as the fault sample database. Second, the energy interval database of the single-coil no-load back EMF residual with different numbers of magnetic pole demagnetization is established. Demagnetization fault detection and degree evaluation are performed by the real-time acquired amplitudes of the single-coil no-load back EMF residual. The number of demagnetization poles is determined by comparing the energy of the single-coil no-load back EMF residual with the energy interval database. Demagnetization mode recognition and magnetic pole positioning are realized by analyzing the correlation coefficients between normalized the single-coil no-load back EMF residual and the fault sample database. Finally, results of analysis of the finite element simulation validate the feasibility and effectiveness of the proposed method.

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Marinkovic, Branko, Miroslav Grujic, Dusko Marinkovic, Jovan Crnobarac, Jelena Marinkovic, Goran Jacimovic, and Dragoslav-Vlad Mircov. "Use of biophysical methods to improve yields and quality of agricultural products." Journal of Agricultural Sciences, Belgrade 53, no. 3 (2008): 235–42. http://dx.doi.org/10.2298/jas0803235m.

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Until as recently as a century ago, the exposure of biological systems to radiation was limited only to the natural sources. Today, however, a broad range of radiation types and doses have found a wide variety of uses and applications, so much so that it would be difficult to make a list of all the areas of human activity in which radiation is used for one purpose or another. The study of radiation effects on individuals and populations as a whole has become important only with the development of methods and sources of man-made radiation. Given that what is present in this case are physical effects on biological systems (living organisms), all these methods can be placed under the heading of biophysical influences. In the last 50 years, the effects of extremely low-frequency electromagnetic fields (ELF-EMF) have been studied with great diligence. These fields are the ones most commonly found in the human environment and they have been used in our studies in this field. The present paper provides a brief review of the literature data and our findings on the effects of ELF-EMF on various crop species using the RIES (Resonant Impulse Electromagnetic Stimulation) method, developed at the Faculty of Agriculture of the University of Novi Sad.

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Pokhodzey, L. V., Yu P. Paltsev, and E. A. Rudneva. "ELECTROMAGNETIC CONDITIONS HYGIENIC ASSESSMENT AT WORKPLACES WITH PERSONAL COMPUTERS: HISTORY AND PRESENT STATUS." Hygiene and sanitation 98, no. 11 (November 15, 2019): 1196–200. http://dx.doi.org/10.18821/0016-9900-2019-98-11-1196-1200.

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Introduction. Currently, in force hygienic normative-methodical documents (SanPiN 2.2.2/2.4.1340-03, SanPiN 2.2.2/2.4.2620-10, SanPiN 2.2.4.3359-16) do not allow to objectively estimating EMF on modern workplaces of personal computers (PCs) users by and other means of information and communication technologies (ICT). Aim of the study is scientific substantiation of improvement of normative-methodical documentation on hygienic regulation and evaluation of EMF in computerized workplaces using modern ICT. Material and methods. The analytical method of evaluation of modern normative-methodical documentation regulating hygienic norms and methods of evaluation of EMF in the workplace of PC users is used. More than 11 thousand measurements of EMF levels were carried out. Results. A critical analysis of the current hygienic regulations of EMF in the workplace of PC users and other means of ICT in Russia showed they to be not scientifically justified, and the existing methodology does not allow an adequate hygienic assessing of the electromagnetic environment (EME). The main sources forming EME on modern workplaces of PC users are both PCs, and switching power supplies, network support devices (UPS), cable lines, wiring, broadband wireless access systems (base stations, Wi-Fi routers, access points, external and built-in laptops USB modems), cell phones, lamps of local and general lighting. EMFs on a workplace of PC users are characterized by complex amplitude-frequency composition: electric and magnetic fields at frequencies of 30 Hz - 300 kHz, EMF at frequencies above 300 MHz, electrostatic fields, hypogeomagnetic fields. New EMF hygienic standards at workplaces of PC users and other means of ICT are scientifically proved. Conclusion. The introduction of new regulations will ensure an adequate hygienic assessment of EMF in the workplaces of PC users in each normalized frequency band in total from all sources and will eliminate the current contradictions and shortcomings. The introduction of new EMF hygienic standards in the practice of sanitary and epidemiological supervision will preserve the health of the PC users and other ICT facilities.

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Gül, Mehmet, Mehmet Cihan Yavaş, and Serkan Dündar. "Protective effect of Melatonin and Ganoderma lucidum against the negative effects of extremely low frequency electric and magnetic fields in the periodontal tissues." International Dental Research 9, no. 3 (December 31, 2019): 119–26. http://dx.doi.org/10.5577/intdentres.2019.vol9.no3.5.

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Aim:The purpose of this study was to determine whether extremely low frequency electric and magnetic field (ELF-EMF) had any detrimental effects on periodontal tissue and to investigate, histologically and immunohistochemically whether melatonin (MLT) and Ganoderma lucidum (GL) had a protective role against these detrimental effects. Methodology:A total of 56 adults, male Wistar Albino rats were used in this study. Rats were divided into 7 equal groups and exposed to ELF-EMF, which was produced by a high voltage source, 8 hours / day for 26 days. GL (20 mg / kg / day) and MLT (10 mg / kg / day) were administered by the oral gavage and intraperitoneal method. Results: Fibrous degeneration in the periodontal membrane, inflammatory cell infiltration, connective tissue fiber organization, dilation, and hemorrhage in the blood vessels changes were determined in the periodontal tissue of the rats in groups I and IV. A statistically significant difference was determined in the groups treated with MLT and GL (p<0.05). Conclusions: It has been determined that ELF-EMF exposure causes histological changes in the periodontal tissue of rats and that MLT and GL may protect against these effects. How to cite this article: Gül M, Yavaş MC, Dündar S. Protective effect of Melatonin and Ganoderma lucidum against the negative effects of extremely low frequency electric and magnetic fields in the periodontal tissues. Int Dent Res 2019;9(3):119-26. Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

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Wang, Song Lin, and Shun Yi Xie. "Adaptive Sliding Mode Observer for Back-EMF in Direct Torque Control of Brushless DC Motor." Advanced Materials Research 850-851 (December 2013): 572–75. http://dx.doi.org/10.4028/www.scientific.net/amr.850-851.572.

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The key issue of feedback torque calculation in BLDCM-DTC system is how to get the accurate estimation of back-emf. The influences form the deviation of resistance and inductance on traditional back-emf sliding mode observer (SMO) and relevant torque observation results are analyzed. To advance the accuracy of the torque estimation, an adaptive sliding mode observer is designed to estimate the back-emf of the BLDCM and then get torque estimation from the back-emf estimation. The proposed sliding mode observer can also implement the online identification of the stator resistance and inductance simultaneously. Simulation results demonstrate the proposed method is valid and effective.

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Doddamani, Vijaykumar H., K. H. Raveesha, B. K. Prasad, and Ruchita Kumari. "On a Technique to Relate EMF & Rate of Change of Magnetic Flux." International Letters of Chemistry, Physics and Astronomy 44 (January 2015): 50–56. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.44.50.

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Faradays law of Induction is the principle of generating electricity in Hydro, Thermal, Wind and Nuclear power stations. In this paper we present a method to study the relationship between induced electromagnetic force (EMF) and the rate of change of Magnetic field and hence to verify this principle. This method involves the rotation of a magnet fixed to a rotor at different angular speeds and to find the EMF induced in the copper coil kept close to the rotor. The data collected is plotted in MATLAB. The results show that Induced EMF is directly proportional to the rate change of Magnetic flux with a correlation coefficient of 0.98.

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Dafang, Wang, Qi Ji, Zhu Cheng, Liao Jiangmin, and Yuan Yechen. "Strategy of Starting Sensorless BLDCM with Inductance Method and EMF Integration." Mathematical Problems in Engineering 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/146058.

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In, conventional 3-stage start-up method of sensorless brushless direct current motor (BLDCM), the rotor is likely to jitter because rotor position cannot be obtained, and the motor is apt to lose step when it starts with load. These defects limit its use in engineering applications. In order to achieve smooth start in specific direction and guarantee start-up success rate with load, a start-up method based on improved inductance method and electromotive force (EMF) integration is proposed applying different voltage vectors according to rotor position interval judged by inductance method and determining integrator start-up time according to rotor initial position and the EMF. Experiments show that the method guarantees smooth acceleration and increases start-up success rate with load.

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Zhao, Xian Kun. "Back-EMF Zero-Crossing Rotor Position Detection Control of BLDC Motors." Applied Mechanics and Materials 155-156 (February 2012): 643–47. http://dx.doi.org/10.4028/www.scientific.net/amm.155-156.643.

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To compare the similarities and differences between BLDCs and PMSMs firstly, then to present the theory of back-EMF zero-crossing rotor position detection. To propose the control scheme using 56F8013 based on back-EMF method. Finally investigate the research prospect of BLDCS.

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Ge, Yao, Ying Li, Han Wei, Hao Nie, Weitian Ding, Yi Cao, and Yaowei Yu. "A Novel Approach for Measuring the Thickness of Refractory of Metallurgical Vessels." Materials 13, no. 24 (December 10, 2020): 5645. http://dx.doi.org/10.3390/ma13245645.

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The advancement of metallurgical vessels, such as blast furnaces, shaft furnaces, and torpedo ladles, can be better controlled and expanded for a greater lifespan if the thickness of the refractory lining wear is known and predicted. In the past, various methods including radioactive tracers, infrared (IR) thermography, electromagnetic waves, ultrasonic tomography, and temperature field have been tested to determine the thickness of the refractory wall. However, for various reasons, these methods have failed to be effective. This paper presents a novel method—electromotive force (EMF)—for predicting the thickness of refractory lining wear in vessels, including a small-scale vessel in the laboratory, an industrial torpedo ladle, and in the two refining hearths of blast furnaces. The experimental results show that the magnitude of the EMF signal increases with a decrease in wall thickness. Prediction values of the refractory wall thickness are consistent with measured ones. The relative error of EMF measurement for the torpedo ladle is around 6.8%. The EMF measurement of blast furnace hearths is quite accurate, and the relative error is less than 11%.

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Wang, Song Lin, and Shun Yi Xie. "Position Sensorless DTC of BLDC Motor Driver Based on Sliding Mode Observer." Advanced Materials Research 805-806 (September 2013): 954–57. http://dx.doi.org/10.4028/www.scientific.net/amr.805-806.954.

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Direct torque control (DTC) which replaces the conventional current loop with torque loop can directly control the electromagnetic torque in order to reduce the torque error within the hysteresis bandwidth, and it can attenuated commutation torque ripple and the torque ripple of brushless DC (BLDC) motor with un-ideal back electromotive force (EMF) waveforms. Further, the key issue of feedback torque calculation in torque loop is the estimation of back-EMF in sensorless DTC of BLDC motor. So a sliding mode observer (SMO) is employed to estimate the back-EMF in real time. The torque and rotor speed can be derived from the estimated back-EMF. Simulation results demonstrate the proposed method is valid and effective.

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Xu, Ying, Hua Gao, and Li Guang Zhu. "Theoretical Decomposition Voltage for Related Substance on Molten Salt Electrolysis Method to Remove Steel Surfaces of Sulfide Inclusions." Advanced Materials Research 239-242 (May 2011): 628–31. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.628.

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The theoretical decomposition voltage (EMF) for substances in FeS-CaCl2-NaCl-KCl system was figured out. The results indicate that the EMF increases in sequence of FeS, CaCl2, NaCl and KCl with inert anodes, and it drops with rising of temperature, increases with decreasing of FeS concentration. Under a lower FeS concentration, as a result, the anode effect can occur. Fe would be separated out from cathode and Cl2 would be separated out from anode first in electrolytic desulfurization process.

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Wang, Hui. "BLDC Motor Sensorless Control System Based on ADSP-BF548." Applied Mechanics and Materials 494-495 (February 2014): 1253–56. http://dx.doi.org/10.4028/www.scientific.net/amm.494-495.1253.

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In this thesis , the control strategy based on sensorless BLDCM(Brushless DC Motor) has been researched.A control system for BLDCM operating on ADSP-BF548 has been given. we focus on studying the control strategy of sensorless BLDC motor based on back-EMF detection, and present a control system for BLDC motor based on ADSP-BF548 special for motor control. The calculation method of back EMF in BLDC motor was deduced and the hardware circuit of line voltage detecting was designed. A pre-position starting tactics based on back EMF detection and a tactics of phase converting by postponing back-emf-zero-crossing detecting was designed. The signal wave was filtered by postponing back-emf-zero-crossing detecting when back-emf-zero-crossing had been detected. To release the phase delay caused by hardware filtering, a phase compensation algorithm has been designed. The PID adjusting algorithm and other strategy are designed in this program. Experimental results show that the control system has good speed adjusting performance and runs stably.

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Yu, Hai Ping, Chun Feng Li, and Jiang Hua Deng. "Forecast of Discharge Voltage for Electromagnetic Tube Forming Based on FEM Analysis." Materials Science Forum 575-578 (April 2008): 192–97. http://dx.doi.org/10.4028/www.scientific.net/msf.575-578.192.

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Forecast of discharge parameters is one of the key problems needed to solve urgently for applications of electromagnetic forming technology (EMF). In this work, the forecast of discharge voltage for electromagnetic tube forming has been investigated through a combination of the sequential coupling numerical simulation of EMF process and the design optimization of tube deformation. The optimum design of tube deformation during EMF process is discussed. The relative error between the experimental value and the forecast one is less than 5.9%, which indicates that the discharge voltage forecast method is feasible. This forecast method will be a favorable way for the optimum design of electromagnetic sheet metal forming and tube forming with die.

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Xu, Xing-Lei, Xiu-Xia Wang, and Hong-Yi Fan. "Energy variation of mesoscopic L–C electric circuit in external electromagnetic field." International Journal of Modern Physics B 29, no. 23 (September 17, 2015): 1550169. http://dx.doi.org/10.1142/s0217979215501696.

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In this paper, we investigate energy variation of mesoscopic L–C electric circuit in external electromagnetic field (EMF) due to the energy flow of EMF, we consider this a diffusion process governed by the master equation for diffusion channel with the diffusion rate being determined by the energy flow of EMF. By using the entangled state representation and the method of integration within ordered product of operators we derive time evolution law of the initial density operator of the circuit and the energy variation formula.

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Kameda, Kazuo, Katsunori Yamaguchi, Hiroshi Horie, and Toshiko Kon. "Thermodynamic Properties of Liquid Te-Pb Alloys by EMF Method." Journal of the Japan Institute of Metals 57, no. 7 (1993): 774–80. http://dx.doi.org/10.2320/jinstmet1952.57.7_774.

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