Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: Electric waves Measurement.
Статті в журналах з теми "Electric waves Measurement"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 статей у журналах для дослідження на тему "Electric waves Measurement".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте статті в журналах для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Kural, Aleksander, Rhys Pullin, C. A. Featherston, J. Lees, J. Naylon, C. Paget, and Karen M. Holford. "Wireless Power Transmission Using Ultrasonic Guided Waves – Electric Circuit Measurement and Simulation." Key Engineering Materials 518 (July 2012): 445–54. http://dx.doi.org/10.4028/www.scientific.net/kem.518.445.
Повний текст джерелаАнотація:
A project investigating the possibility to transmit electrical power (several mW) along the structure of an aircraft by using an intermediate medium of ultrasonic Lamb waves is being carried out at Cardiff University in conjunction with Airbus. This power supply method is aimed at wireless, surface-bonded sensor packages, primarily for the aircraft structural health monitoring (SHM) applications. It is expected to replace conventional batteries or energy harvesting devices. This paper presents methods of piezoelectric transducer characterisation, electric power measurement and electric circuit simulation that were developed in support of the ultrasonic power transmission project. The unique combination of low power and a high AC frequency range (up to 200 kHz) precluded the use of conventional power measurement instruments and called for a tailored system and software to be developed. Two approaches were developed: one relying on the measurement of the ultrasonic transducers impedance characteristics and their subsequent use in a circuit simulation; and another relying on the direct measurement of voltage waveforms in the power transmission setup. The two methods were found to be capable of producing closely matching results up to 300 kHz. Results of early power transmission trials are also presented. The optimum approach resulted in 1 mW of power transmission over a distance of 74 cm in a 1.5 mm thick aluminium plate.
2
Maeda, Masataka, Tatsuo Takada, and Masao Ide. "Measurement of Electric Field Distributions in Solid Dielectrics Using Ultrasonic Waves." Japanese Journal of Applied Physics 29, S1 (January 1, 1990): 203. http://dx.doi.org/10.7567/jjaps.29s1.203.
Повний текст джерела
3
PLYSHCHENKOV, BORIS D., and ANATOLY A. NIKITIN. "BOREHOLE ACOUSTIC AND ELECTRIC STONELEY WAVES AND PERMEABILITY." Journal of Computational Acoustics 18, no. 02 (June 2010): 87–115. http://dx.doi.org/10.1142/s0218396x10004085.
Повний текст джерелаАнотація:
New way for quantitative evaluation of any value of formation permeability based on numerical experiments with Pride's model of electrokinetic phenomena is presented. This approach is based on simultaneous measurement of pressure field and axial component of electric field excited by an acoustic source in fluid-filled borehole with help a set of receivers in borehole. Frequency dependence of ratio of the complex-valued amplitudes of the electric Stoneley wave to the pressure Stoneley wave obtained as a result of plane-wave decomposition of pressure field and mentioned component of electric field carries important information about permeability. In case of open and sealed pores on borehole wall were obtained enough simple analytical expressions for this ratio.
4
Im, Kwang-Hee, Sun-Kyu Kim, Jong-An Jung, Young-Tae Cho, Yong-Deuck Woo, and Chien-Ping Chiou. "NDE Terahertz Wave Techniques for Measurement of Defect Detection on Composite Panels of Honeycomb Sandwiches." Electronics 9, no. 9 (August 21, 2020): 1360. http://dx.doi.org/10.3390/electronics9091360.
Повний текст джерелаАнотація:
Terahertz wave (T-ray) technologies have become a popular topic in scientific research over the last two decades, and can be utilized in nondestructive evaluation (NDE) techniques. This study suggests an optimal scanning technique method for honeycomb sandwich composite panels, where skins were utilized with two different skins, namely, carbon fiber-reinforced plastic (CFRP) skin and glass fiber-reinforced plastic (GFRP) skin, as layers of the panel surfaces. Foreign objects were artificially inserted between the skins and honeycomb cells in the honeycomb sandwich composite panels. For this experiment, optimal T-ray scanning methods were performed to examine defects based on the angle between the one-ply thin fiber skin axis and the angle of the electric field (E-field) according to the amount of conductivity of the honeycomb sandwich composite panels. In order to confirm the fundamental characteristics of the terahertz waves, the refractive index values of the GFRP composites were experimentally obtained and analyzed, with the data agreeing with known solutions. Terahertz waves (T-rays) were shown to have limited penetration in honeycomb sandwich composite panels when utilized with a skin of carbon fibers. Therefore, T-rays were found to interact with the electrical conductivity and electric field direction of honeycomb sandwich composite panels with glass fiber skins. The T-ray images were obtained regardless of the electric field direction and the fiber direction. In the honeycomb sandwich composite panels with carbon fiber skins, the T-ray images with higher signal-to-noise (S/N) ratios depended on the scanning angle between the angle of the carbon fiber and the angle of the electric field. Thus, the angle of optimum detection measurement was confirmed to be 90° between the E-field and the fiber direction, particularly when using a carbon fiber skin.
5
Sugaya, Toshio, and Yukio Kawano. "Frequency-Tunable Terahertz Plasmonic Structure Based on the Solid Immersed Method for Sensing." Sensors 21, no. 4 (February 18, 2021): 1419. http://dx.doi.org/10.3390/s21041419.
Повний текст джерелаАнотація:
Terahertz waves are located in the frequency band between radio waves and light, and they are being considered for various applications as a light source. Generally, the use of light requires focusing; however, when a terahertz wave is irradiated onto a small detector or a small measurement sample, its wavelength, which is much longer than that of visible light, causes problems. The diffraction limit may make it impossible to focus the terahertz light down to the desired range by using common lenses. The Bull’s Eye structure, which is a plasmonic structure, is a promising tool for focusing the terahertz light beyond the diffraction limit and into the sub-wavelength region. By utilizing the surface plasmon propagation, the electric field intensity and transmission coefficient can be enhanced. In this study, we improved the electric field intensity and light focusing in a small region by adapting the solid immersion method (SIM) from our previous study, which had a frequency-tunable nonconcentric Bull’s Eye structure. Through electromagnetic field analysis, the electric field intensity was confirmed to be approximately 20 times higher than that of the case without the SIM, and the transmission measurements confirmed that the transmission through an aperture had a gap of 1/20 that of the wavelength. This fabricated device can be used in imaging and sensing applications because of the close contact between the transmission aperture and the measurement sample.
6
Bury, Peter, Marek Veveričík, František Černobila, Peter Kopčanský, Milan Timko, and Vlasta Závišová. "Study of Structural Changes in Nematic Liquid Crystals Doped with Magnetic Nanoparticles Using Surface Acoustic Waves." Crystals 10, no. 11 (November 10, 2020): 1023. http://dx.doi.org/10.3390/cryst10111023.
Повний текст джерелаАнотація:
The surface acoustic waves (SAWs) were used to study the effect of magnetic nanoparticles on nematic liquid crystal (NLC) behavior in weak magnetic and electric fields. The measurement of the attenuation of SAW propagating along the interface between piezoelectric substrate and liquid crystal is showed as an effective tool to study processes of structural changes. The magnetic nanoparticles Fe3O4 of nanorod shape and different low volume concentration were added to the NLC (4-(trans-4′-n-hexylcyclohexyl)-isothiocyanatobenzene (6CHBT)) during its isotropic phase. In contrast to undoped liquid crystals the distinctive different SAW attenuation responses induced by both magnetic and also electric fields in studied NLC samples were observed suggesting both structural changes and the orientational coupling between both magnetic and electric moments of nanoparticles and the director of the NLC molecules. Experimental measurements including the investigation under linearly increasing and/or jumped magnetic and electrical fields, respectively, as well as the investigation of temperature and time influences on structural changes were done. The investigation of the SAW anisotropy gives supplemental information about the internal structure of nanoparticles in investigated NLCs. In addition, some magneto-optical investigations were performed to support SAW results and study their stability and switching time. The analysis of observed SAW attenuation characteristics confirmed the role of concentration of magnetic nanoparticles on the resultant behavior of investigated NLC compounds. Obtained results are discussed within the context of previous ones. The theoretical background of the presented SAW investigation is introduced, too.
7
Myllys, M., P. Henri, X. Vallières, N. Gilet, H. Nilsson, E. Palmerio, L. Turc, A. Wellbrock, R. Goldstein, and O. Witasse. "Electric field measurements at the plasma frequency around comet 67P by RPC-MIP on board Rosetta." Astronomy & Astrophysics 652 (August 2021): A73. http://dx.doi.org/10.1051/0004-6361/201936633.
Повний текст джерелаАнотація:
Context. The Mutual Impedance Probe (RPC-MIP) carried by the Rosetta spacecraft monitored both the plasma density and the electric field in the close environment of comet 67P/Churyumov–Gerasimenko (67P), as the instrument was operating alternatively in two main modes: active and passive. The active mode is used primarily to perform plasma density measurements, while the passive mode enables the instrument to work as a wave analyzer. Aims. We are reporting electric field emissions at the plasma frequency near comet 67P observed by RPC-MIP passive mode. The electric field emissions are related to Langmuir waves within the cometary ionized environment. In addition, this study gives feedback on the density measurement capability of RPC-MIP in the presence of cold electrons. Methods. We studied the occurrence rate of the electric field emissions as well as their dependence on solar wind structures like stream interaction regions (SIRs) and coronal mass ejections (CMEs). Results. We are showing that strong electric field emissions at the plasma frequency near 67P were present sporadically throughout the period when Rosetta was escorting the comet, without being continuous, as the occurrence rate is reported to be of about 1% of all the measured RPC-MIP passive spectra showing strong electric field emissions. The Langmuir wave activity monitored by RPC-MIP showed measurable enhancements during SIR or CME interactions and near perihelion. Conclusions. According to our results, Langmuir waves are a common feature at 67P during the passage of SIRs. Comparing the plasma frequency given by the RPC-MIP passive mode during Langmuir wave periods with the RPC-MIP active mode observations, we conclude that the measurement accuracy of RPC-MIP depends on the operational submode when the cold electron component dominates the electron density.
8
Kozaczka, Eugeniusz, Jacek Domagalski, Grażyna Grelowska, and Ignacy Gloza. "Identification of hydro-acoustic waves emitted from floating units during mooring tests." Polish Maritime Research 14, no. 4 (October 1, 2007): 40–46. http://dx.doi.org/10.2478/v10012-007-0038-5.
Повний текст джерелаАнотація:
Identification of hydro-acoustic waves emitted from floating units during mooring tests Measurements of hydro-acoustic noise emitted from vessels are a.o. a subject of the tests carried out in the control measurement ranges of the Navy. The measurements are performed both on anchored and floating vessels. Acoustic field of vessels is changing along with their speed changing and is associated with acoustic activity of wave sources installed in vessel's hull (main engines, electric generating sets, reduction gears, pumps, shaft-lines, piping, ventilating ducts etc) as well as hydro-dynamic sources such as screw propellers and water flow around the hull [5, 7]. Vibration energy generated by the onboard devices is transferred through ship structural elements to water where it propagates in the form of hydro-acoustic waves of a wide frequency band.
9
PLYSHCHENKOV, BORIS D., and ANATOLY A. NIKITIN. "QUANTITATIVE EVALUATION OF FORMATION PERMEABILITY FROM ACOUSTIC AND ELECTRIC STONELEY WAVES." International Journal of Applied Mechanics 02, no. 03 (September 2010): 585–615. http://dx.doi.org/10.1142/s1758825110000676.
Повний текст джерелаАнотація:
Numerical experiments based on Pride's model of electrokinetic phenomena have shown that electromagnetic Stoneley waves as well as pressure Stoneley waves are most sensitive to permeability variations. A new way for quantitative evaluation of any value of formation permeability is presented. It is based on simultaneous measurement of pressure field and axial component of electric field excited by an acoustic source in fluid-filled borehole with help from a set of receivers in borehole. Frequency dependence of ratio of the complex-valued amplitudes of the electric Stoneley wave to the pressure Stoneley wave obtained as a result of plane waves decomposition of pressure field and mentioned component of electric field carries important information about permeability. The ratio of the real part of this ratio to its imaginary part is very sensitive to permeability variations. The approximate analytical expressions for this ratio derived for open and sealed pores on borehole wall are base for construction of a new way of quantitative evaluation of formation permeability.
10
Hraniak, V. "METHOD AND MEANS FOR MEASURING THE TEMPERATURE OF THE POLE WINDINGS OF THE ELECTRIC MACHINE ROTOR." Odes’kyi Politechnichnyi Universytet Pratsi 1, no. 63 (2021): 78–87. http://dx.doi.org/10.15276/opu.1.63.2021.08.
Повний текст джерелаАнотація:
The temperature of the pole windings is one of the main informative parameters, the deviation of which may indicate the presence of a number of common defects of electrical machines. However, the implementation of high-precision means for measuring the temperature of the pole windings of the electric machine rotor is associated with a number of technical difficulties. The aim is to increase the accuracy of measuring the temperature of the pole windings of the rotor of an electric machine by developing a contactless method and means of measuring the temperature of the pole windings of the rotor in real time. The paper shows that the existing most common methods of temperature measurement have significant disadvantages that limit the possibility of their use for the implementation of means of measuring the pole windings of the rotor of an electric machine. A bispectral pyrometric method of temperature measurement is proposed, which provides simultaneous conversion into voltage of functionally temperature-dependent spectral densities of radiation for two spectrally close electromagnetic waves with subsequent finding of their ratio, which allowed to remove the most significant components of methodical measurement characteristic of classical pyrometers. The design of the bispectral pyrometric measuring system of temperature of pole windings of a rotor of rotating electric machines realized on the basis of the offered method of measurement, suitable for work in a real-time mode together with systems of control of a technical condition and diagnostics is developed.
11
Yu, Hai Bo, Jia Liu, Chun Yu Wang, Li Li, and Rui Ming Tong. "Preliminary Study on the Effect of Operating Conditions on the Measurement Accuracy of Electronic Type Electric Energy Meter." Advanced Materials Research 834-836 (October 2013): 1246–50. http://dx.doi.org/10.4028/www.scientific.net/amr.834-836.1246.
Повний текст джерелаАнотація:
The verification of electronic type electric energy meter is under strict reference conditions, but some special operating conditions at locale will exceed the standard scopes. In order to improve the calculation accuracy and operating reliability of electric energy meter under operating conditions, it is necessary to study the operating conditions. According to the working principle and the standard verification regulation of electronic type electric energy meter, this paper summarizes these operating conditions: low power factor, harmonic waves, dynamic impulsive load, voltage fluctuation and outside magnetic field of power frequency, then analyzes the causes of operating conditions and their influence on electronic type electric energy meter, eventually lays foundation for thorough and systematic study of electric energy meter in the operating conditions, and establishes measurement center database of operating conditions.
12
Elhady, Alaa, and Eihab Abdel-Rahman. "Measurement of the electric permittivity using Bleustein–Gulyaev wave sensor." Journal of Micromechanics and Microengineering 32, no. 3 (February 7, 2022): 034004. http://dx.doi.org/10.1088/1361-6439/ac4e78.
Повний текст джерелаАнотація:
Abstract We present a novel compact electric permittivity sensor that exploits Bleustein–Gulyaev waves propagating along the surface of shear-poled piezoelectrics. We formulate the dynamic nonlinear electromechanical partial differential equations of motion governing wave propagation under electromagnetically quasistatic conditions. The permittivity of the medium-under-test was found to influence the sensor eigenvalues, enabling the implementation of a frequency-shift permittivity sensor. Solution of the equations of motion demonstrates resonance of the first and third modes when excited using an interdigitated transducer. We fabricated two sensor prototypes on shear-poled PZT4 and LiNbO3 substrates and used a Vector Network Analyzer to observe the shift in their fundamental natural frequency in the presence of various media-under-test. S 11 measurements show deterministic and repeatable shifts in the resonant frequency of the first mode of the LiNbO3 sensor measured at Δ f 1 = 3.51 MHz for ethanol and Δ f 1 = 7.49 MHz for deionized water where the bare surface frequency was initially at f 1 = 25.27 MHz.
13
He, Penglong, Bo Zhang, and Jinliang He. "Characteristic of acoustic waves generated in dielectrics under divergent electric fields." Journal of Applied Physics 132, no. 24 (December 28, 2022): 244104. http://dx.doi.org/10.1063/5.0125160.
Повний текст джерелаАнотація:
Space charge measurement under divergent electric fields can provide crucial insight into various insulating phenomena, and the space charge reconstruction relies on the relation between the measured acoustic wave and the space charge distribution if the pulsed electroacoustic method is used. However, the relation is still unclear. In this work, the characteristic of acoustic waves generated by a divergent electric field is studied. Three components of electrostatic force leading to acoustic waves, which are surface force, internal Coulomb force, and electrostrictive force, are considered. The relation between the acoustic wave and these three components is provided, and the acoustic wave characteristic is, therefore, investigated. The results show that the acoustic wave exhibits two opposite peaks for each component due to the local distribution of the force, which is different from that with a uniform electric field, and the combined waveform is greatly influenced by the contribution of electrostrictive force, making it challenging to extract space charge information.
14
Constantin, Florin Lucian. "Phase-Sensitive Vector Terahertz Electrometry from Precision Spectroscopy of Molecular Ions." Atoms 8, no. 4 (October 7, 2020): 70. http://dx.doi.org/10.3390/atoms8040070.
Повний текст джерелаАнотація:
This article proposes a new method for sensing THz waves that can allow electric field measurements traceable to the International System of Units and to the fundamental physical constants by using the comparison between precision measurements with cold trapped HD+ ions and accurate predictions of molecular ion theory. The approach exploits the lightshifts induced on the two-photon rovibrational transition at 55.9 THz by a THz wave around 1.3 THz, which is off-resonantly coupled to the HD+ fundamental rotational transition. First, the direction and the magnitude of the static magnetic field applied to the ion trap is calibrated using Zeeman spectroscopy of HD+. Then, a set of lightshifts are converted into the amplitudes and the phases of the THz electric field components in an orthogonal laboratory frame by exploiting the sensitivity of the lightshifts to the intensity, the polarization and the detuning of the THz wave to the HD+ energy levels. The THz electric field measurement uncertainties are estimated for quantum projection noise-limited molecular ion frequency measurements with the current accuracy of molecular ion theory. The method has the potential to improve the sensitivity and accuracy of electric field metrology and may be extended to THz magnetic fields and to optical fields.
15
Křivánek, Ivo. "Dielectric properties of materials at microwave frequencies." Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 56, no. 5 (2008): 125–32. http://dx.doi.org/10.11118/actaun200856050125.
Повний текст джерелаАнотація:
The paper introduces the review of the present state of art in the measurement of the interaction of electromagnetic waves with different kinds of materials. It is analysis of the possibilities of the measurement of the interaction of high frequencies waves (microwaves) with materials and proposal of the experimental method for the studies mentioned above.The electromagnetic field consists of two components: electric and magnetic field. The influence of these components on materials is different. The influence of the magnetic field is negligible and it has no impact on practical use. The influence of the electric field is strong as the interaction between them results in the creation of electric currents in the material (Křivánek and Buchar, 1993).Experiments focused on the evaluation of the complex dielectric permitivity of different materials have been performed. The permitivity of solid material is also measurable by phasemethod, when the specimen is a part of transmission sub-circuit. Microwave instrument for complex permittivity measurement works in X frequency band (8.2–12.5) GHz, the frequency 10.1 GHz was used for all the measurement in the laboratory of physics, Mendel University in Brno. The extensive number of experimental data have been obtained for different materials. The length of the square side of the aerial open end was 50 mm and internal dimensions of waveguides were 23 mm × 10 mm. The samples have form of the plate shape with dimensions 150 mm × 150 mm × 4 mm.
16
Zen, Hardi, Indra Ranu Kusuma, and Endang Widjiati. "Robust Laboratory Scale Seakeeping Test Wave Measurement Method Use Ultrasonic Sensor." IOP Conference Series: Earth and Environmental Science 1081, no. 1 (September 1, 2022): 012042. http://dx.doi.org/10.1088/1755-1315/1081/1/012042.
Повний текст джерелаАнотація:
Abstract The seakeeping test is one of the tests done in the Indonesia Hydrodynamic Laboratory (IHL) test tank on a model ship or floating unit. In the test tank, a wave can be generated by using electric and mechanic wave flaps that are pre-programmed on a certain condition of the wave, i.e. different frequencies and amplitude. To measure waves, produced by a wave generator, a wave measuring instrument is needed that can measure changes in water level in the test tank. The current wave measuring instrument is in the form of a 600 mm twin wire wave probe. This instrument is can be used to measure waves in the test tank but has limitations because it is only placed in one location without being moved. Another method is developed to be used in making alternative measuring instruments using ultrasonic sensors. In this paper, this alternative wave measuring instrument shows that measuring waves even when moving the measurement point to a new point location or following a towing carriage can be done and gives better measurement results. Based on these results, this new measuring instrument can be used in a more complex configuration test in the tank.
17
Fujinawa, Yukio, Kozo Takahashi, Yoichi Noda, Hiroshi Iitaka, and Shinobu Yazaki. "Remote Detection of the Electric Field Change Induced at the Seismic Wave Front from the Start of Fault Rupturing." International Journal of Geophysics 2011 (2011): 1–11. http://dx.doi.org/10.1155/2011/752193.
Повний текст джерелаАнотація:
Seismic waves are generally observed through the measurement of undulating elastic ground motion. We report the remote detection of the Earth's electric field variations almost simultaneously with the start of fault rupturing at about 100 km from the fault region using a special electric measurement. The rare but repeated detection indicates that the phenomenon is real. The characteristic time of diffusion is almost instantaneous, that is, less than 1 second to travel 100 km, more than ten times faster than ordinary seismic P wave propagation. We suggest that the measured electric field changes are produced by the electrokinetic effect through increased pore water pressure of the seismic pulse. It is also suggested that the long range propagation is due to the surface wave mode confined near the interface of the different conductivity. The length scale of the finite strength of the electric field is 16 km, 160 km for electric conductivity of 0.01, 0.001, Sm−1, respectively. This phenomenon suggests a new seismic sensing method and a new earthquake early warning system providing more seconds of lead time.
18
Kasaba, Y., J. L. Bougeret, L. G. Blomberg, H. Kojima, S. Yagitani, M. Moncuquet, J. G. Trotignon, et al. "The Plasma Wave Investigation (PWI) onboard the BepiColombo/MMO: First measurement of electric fields, electromagnetic waves, and radio waves around Mercury." Planetary and Space Science 58, no. 1-2 (January 2010): 238–78. http://dx.doi.org/10.1016/j.pss.2008.07.017.
Повний текст джерела
19
Spratt, Kyle S., and Jonathan S. Abel. "Measurement and modeling of an electromechanical spring reverb device." Journal of the Acoustical Society of America 152, no. 4 (October 2022): A220. http://dx.doi.org/10.1121/10.0016069.
Повний текст джерелаАнотація:
A spring reverb is an electromechanical device used to artificially reverberate an audio signal, i.e. to impart a sense of spaciousness to the audio signal, as if the sound were being emitted into a reverberant acoustic space. The device consists of a number of helical springs set into motion by electrically driven magnetized beads, with the elastic wave motion along the springs being analogous to acoustic waves propagating along the various dimensions of a room. While originally invented by the Hammond organ company to add a sense of spaciousness to the sound of their electric organs, spring reverbs have been used in a number of electronic instruments and audio devices over the years, with probably the most iconic and enduring use being in classic electric guitar amplifiers. In this talk, a general overview of the history and technical aspects of spring reverb devices will be given, with particular emphasis placed on the highly dispersive nature of elastic wave propagation along helical springs, which it will be argued is primarily responsible for the distinctive sound of the device. Finally, a simplified computation model will be presented that captures the salient features of a spring reverb device.
20
Hidayat, M. Reza, Mohamad Hamzah Zamzam, and Salita Ulitia Prini. "Excitation Analysis of Transverse Electric Mode Rectangular Waveguide." Jurnal Elektronika dan Telekomunikasi 20, no. 1 (August 31, 2020): 1. http://dx.doi.org/10.14203/jet.v20.1-8.
Повний текст джерелаАнотація:
A waveguide is a transmission medium in the form of a pipe and is made from a single conductor. A waveguide has the function of delivering electromagnetic waves with a frequency of 300 MHz - 300 GHz and is able to direct the waves in a particular direction. In its development, a waveguide can be used as a filter. A filter consists of several circuits designed to pass signals that are generated at a specific frequency and attenuate undesired signals. One type of filter that can pass a signal in a particular frequency range and block signals that are not included in that frequency range is a bandpass filter. In this article, we study a rationing analysis on rectangular waveguide using TEmn mode followed by an implementation of a bandpass filter in the frequency range of 3.3-3.5 GHz for S-Band Wireless Broadband and Fixed Satellite. The observation process is done by shifting the position of the connector (power supply) as much as five times the shift to get the results as desired. Based on the analysis of the simulation process using Ansoft HFSS software, it is observed that the optimized results of the rectangular waveguide mode TE10 were obtained at a distance between connectors of 30 mm with a cut-off frequency of 3.3 GHz, the value of the return loss parameter of -34.442 dB and an insertion loss of -0.039 dB. Whereas, the optimized TE20 mode can be obtained at a distance of 70 mm between connectors, with a cut-off frequency of 3.5 GHz, the value of the return loss parameter of -28.718 dB and an insertion loss of -0.045. The measurement of TE10 mode in our Vector Network Analyzer (VNA) shows a cut-off frequency of 3.2 GHz, with a value of the return loss of -18.73 dB and an insertion loss of -2.70 dB. Meanwhile, a measurement of TE20 mode results in a cut-off frequency of 3.2 GHz, with a value of the return loss of -5.89 dB and an insertion loss of -4.31 dB.
21
Mordasov, M. M., A. P. Savenkov, and K. E. Chechetov. "Non-contact methods for measuring the surface tension of liquids (review)." Industrial laboratory. Diagnostics of materials 86, no. 4 (April 23, 2020): 29–38. http://dx.doi.org/10.26896/1028-6861-2020-86-4-29-38.
Повний текст джерелаАнотація:
A review of non-contact methods for determining the surface tension of liquids along with analysis of the physical effects underlying them is presented. A review of non-contact methods for determining the surface tension of liquids along with analysis of the physical effects underlying them is presented. The advantages, disadvantages, possible ranges of measurements and scope of non-contact methods are discussed. Passive methods do not require any stimulation of the measurement object whereas active methods, when implemented, affect the liquid under study. Electrical, electromagnetic, acoustic, jet, and mechanical methods used for excitation of capillary waves are described in analysis of the methods based on capillary waves intended to study the properties of surface-active substances. We also considered methods based on the processes occurred in an oscillating or rotating levitating drop of liquid (containerless technology) used to study the properties of melts and methods based on local deformation of the liquid surface by the electric field, acoustic pulse, and gas jet. It is shown that aerodynamic methods based on deformation of the liquid surface under control by a gas stream are the most promising for standard laboratory conditions. It is noted that containerless methods should be used in zero gravity tests, whereas the methods based on capillary waves or deformation of the liquid surface with a focused acoustic pulse appeared useful in testing inviscid liquids. Methods based on electrical deformation of the liquid surface under control are limited with the thickness of the liquid layer, relatively high sensitivity to the density and dielectric constant of the liquid, and some other uncontrolled factors. It was also noted that aerodynamic non-contact method of the surface tension determination is characterized by low sensitivity to the density and viscosity of the controlled liquid. The presented review of non-contact methods of the surface tension determination provides optimal choice of the method most suited for solving specific measurement problems.
22
Zhu, Zhenya, M. Nafi Toksöz, and Daniel R. Burns. "Electroseismic and seismoelectric measurements of rock samples in a water tank." GEOPHYSICS 73, no. 5 (September 2008): E153—E164. http://dx.doi.org/10.1190/1.2952570.
Повний текст джерелаАнотація:
An electromagnetic (EM) or seismic wave can induce seismic or EM waves because of the electrokinetic conversion based on the electric double layer in a fluid-saturated porous medium. We tested a new method for observing electroseismic and seismoelectric conversions in rock samples. Our method is designed to overcome the shortcoming of previous attempts to separate signals generated by a continuous electric or seismic source in a small container. We first observed acoustic fields around electrodes excited by an electric pulse in a water tank or in a water-saturated porous sample. In our approach, we immersed rock samples in a water tank and measure the seismic or electric responses using electric or acoustic pulses conveyed through the immersed electrodes or hydrophone. We measured electroseismic- and seismoelectric-frequency responses in Berea Sandstone and Westerly Granite samples at a frequency range of [Formula: see text]. The measurements clearly separate the effects of the electric source, background noises, and signals. We calculate the normalized electroseismic and seismoelectric coupling coefficients for rock samples and confirm our results by comparing them with those theoretically simulated in a closed-capillary model. The variation of normalized coupling coefficients in the frequency domain is similar to that in theoretical predictions. Our measurement method can be used to investigate electroseismic and seismoelectric properties for petroleum exploration applications.
23
Harshkova, Yuliya S., Sergey V. Maly, Andrei V. Tkachenia, and Igor E. Kheidorov. "Increasing the metrological characteristics of anechoic chambers due to a posteriori analysis based on artificial neural networks." Journal of the Belarusian State University. Physics, no. 3 (October 5, 2022): 93–103. http://dx.doi.org/10.33581/2520-2243-2022-3-93-103.
Повний текст джерелаАнотація:
This article considers the possibility of improving the metrological characteristics of an anechoic chamber due to a posteriori processing of measurement results based on a generative adversarial model of an artificial neural network in order to reduce the influence on the distribution of the electromagnetic field in the measuring zone of waves reflected from the outer boundaries of the chamber and the equipment located in it. The training of the neural network was carried out on a data set obtained as part of a computational experiment and including the distribution of the electromagnetic field in the anechoic region for the model of an anechoic chamber and free space for given source layouts. The distributions of the real and imaginary parts of the electric component of the electromagnetic field were encoded with colour images. On the example of two-dimensional models of anechoic chambers, the practical feasibility of the proposed approach to a posteriori processing of measurement results is shown. Methods for estimating the accuracy of a posteriori processing of measurement results based on the metrics used to assess the quality of graphic images and calculating the errors in the amplitudes of the electric component of the electromagnetic field are given. The possibility of implementing the proposed method of a posteriori analysis in the framework of natural microwave measurements in anechoic chambers is assessed.
24
Cao, Bing Xia, and Xiao Lin Qiao. "Schumann Resonance Measurement Based on Nonlinear Interaction." Key Engineering Materials 439-440 (June 2010): 1294–99. http://dx.doi.org/10.4028/www.scientific.net/kem.439-440.1294.
Повний текст джерелаАнотація:
Schumann Resonance relates with global temperature variations, new geophysics phenomena in the low ionosphere and short-term earthquake prediction etc. In this paper based on the nonlinear modulation model of high frequency and extreme-low frequency electromagnetic waves in low ionosphere, the Schumann Resonance observing is researched. Taking the fair weather electric field in account, the cross modulation index was 4.2×10-4. At the first Schumann Resonance observatory of China, the first 4 peaks of Schumann Resonance respectively at 7, 14, 20, 26Hz were obtained in demodulation spectra of the high frequency time service signals. The parameter characteristics of Schumann Resonance in the low ionosphere were analyzed under the geographical condition of middle latitude area. The feasibility of Schumann Resonance measurement by demodulating the spectra of HF has been verified. The non-linearity between Schumann Resonance and very low frequency signals also was discussed.
25
Zhu, Zhenya, Matthijs W. Haartsen, and M. Nafi Toksöz. "Experimental studies of electrokinetic conversions in fluid‐saturated borehole models." GEOPHYSICS 64, no. 5 (September 1999): 1349–56. http://dx.doi.org/10.1190/1.1444639.
Повний текст джерелаАнотація:
Experimental and theoretical studies show that there are electromagnetic (EM) fields generated by seismic waves with two kinds of conversion mechanisms in a fluid‐saturated, porous medium. Within a homogeneous formation, the seismic wave generates a seismoelectric field that exists only in the area disturbed by the seismic wave and whose apparent velocity is that of the seismic wave. At an interface between differing formation properties, the generated seismoelectric wave is a propagating EM wave that can be detected everywhere. An electrode, used as a receiver on the ground surface, can detect the propagating EM wave generated at an interface, but cannot detect the seismoelectric field generated in a homogeneous formation. When the electrode is in a borehole and close to a porous formation, it can detect both the EM waves and the seismoelectric field. In this paper, electrokinetic measurements are performed with borehole models made of natural rocks or artificial materials. Experimental results show that the Stoneley wave and other acoustic modes, excited by a monopole source in the borehole models, generate seismoelectric fields in fluid‐saturated formations. The electric components of the seismoelectric fields can be detected by an electrode in the borehole or on the borehole wall. The amplitude and frequency of the seismoelectric fields are related not only to the seismic wave, but also to formation properties such as permeability, conductivity, etc. Comparison between the waveforms of the seismoelectric signals and acoustic logging waves suggests that seismoelectric well logging may explore the different properties of the formation. Electroseismic measurements are also performed with these borehole models. The electric pulse through the electrode in the borehole or on the borehole wall induces Stoneley waves in fluid‐saturated models that can be received by a monopole transducer in the same borehole. These measurement methods (seismoelectric logging or electroseismic logging) might directly apply to well logging to investigate formation properties related to the pore fluid flow.
26
Chng, Tat Loon, David Z. Pai, Olivier Guaitella, Svetlana M. Starikovskaia, and Anne Bourdon. "Effect of the electric field profile on the accuracy of E-FISH measurements in ionization waves." Plasma Sources Science and Technology 31, no. 1 (January 1, 2022): 015010. http://dx.doi.org/10.1088/1361-6595/ac4592.
Повний текст джерелаАнотація:
Abstract Electric field induced second harmonic (E-FISH) generation has emerged as a versatile tool for measuring absolute electric field strengths in time-varying, non-equilibrium plasmas and gas discharges. Yet recent work has demonstrated that the E-FISH signal, when produced with tightly focused laser beams, exhibits a strong dependence on both the length and shape of the applied electric field profile (along the axis of laser beam propagation). In this paper, we examine the effect of this dependence more meaningfully, by predicting what an E-FISH experiment would measure in a plasma, using 2D axisymmetric numerical fluid simulations as the true value. A pin-plane nanosecond discharge at atmospheric pressure is adopted as the test configuration, and the electric field evolution during the propagation of the ionization wave (IW) is specifically analysed. We find that the various phases of this evolution (before and up to the front arrival, immediately behind the front and after the connection to the grounded plane) are quite accurately described by three unique electric field profile shapes, each of which produces a different response in the E-FISH signal. As a result, the accuracy of an E-FISH measurement is generally predicted to be comparable in the first and third phases of the IW evolution, and significantly poorer in the second (intermediate) phase. Fortunately, even though the absolute error in the field strength at certain time instants could be large, the overall shape of the field evolution curve is relatively well captured by E-FISH. Guided by the simulation results, we propose a procedure for estimating the error in the initial phase of the IW development, based on the presumption that the starting field profile mirrors that of its corresponding Laplacian conditions before evolving further. We expect that this approach may be readily generalized and applicable to other IW problems or phenomena, thus extending the utility of the E-FISH diagnostic.
27
Tigrine, Z., H.-C. Nataf, N. Schaeffer, P. Cardin, and F. Plunian. "Torsional Alfvén waves in a dipolar magnetic field: experiments and simulations." Geophysical Journal International 219, Supplement_1 (February 28, 2019): S83—S100. http://dx.doi.org/10.1093/gji/ggz112.
Повний текст джерелаАнотація:
SUMMARY The discovery of torsional Alfvén waves (geostrophic Alfvén waves) in the Earth’s core (Gillet et al. 2010) calls for a better understanding of their properties. We present the first experimental observations of torsional Alfvén waves, performed in the DTS-Ω set-up. In this set-up, 50 L of liquid sodium are confined between an inner sphere (ri = 74 mm) and an outer shell (ro = 210 mm). The inner sphere houses a permanent magnet, imposing a dipolar magnetic field (Bmax = 345 mT). Both the inner sphere and the outer shell can rotate around the vertical axis. Alfvén waves are triggered by a sudden jerk of the inner sphere. We study the propagation of these waves when the fluid is initially at rest, and when it spins at a rotation rate up to 15 Hz. We measure the azimuthal magnetic field of the wave at different radii inside the fluid with magnetometers installed in a sleeve. We also record the electric potential signature on the outer shell at several latitudes. Besides, we probe the associated azimuthal velocity field using ultrasound Doppler velocimetry. With a 15 Hz rotation rate, the dynamical regimes we achieve are characterized by dimensionless numbers in the following ranges: Lundquist number 0.5 < Lu < 12, Lehnert number 0.01 < Le < 0.26, Rossby number Ro ∼ 0.1. We observe that the magnetic signal propagates away from the inner sphere, strongly damped by magnetic diffusion. Rotation affects the magnetic signature in a subtle way. Its effect is more pronounced on the surface electric potentials, which are sensitive to the actual fluid velocity of the wave. The ultrasound Doppler probes provide the first experimental measurement of the fluid velocity of an Alfvén wave. To complement these observations, we ran numerical simulations, using the XSHELLS pseudospectral code with parameters as close as possible to the experimental ones. The synthetic magnetic and electric signals match our measurements. The meridional snapshots of the synthetic azimuthal velocity field reveal the formation of geostrophic cylinders expected for torsional Alfvén waves. We establish scaling laws for the magnetic and kinetic energies of Alfvén waves with and without rotation. In both cases, we find that the magnetic energy EM saturates at a level proportional to $Rm_{\rm jerk}^2$, where Rmjerk = Ujerkro/η is the magnetic Reynolds number built with the maximum azimuthal velocity of the inner sphere during the jerk. The $E_K^{\rm max}/E_M^{\rm max}$ ratio (where $E_K^{\rm max}$ is the maximum kinetic energy), close to 1 for very quick jerks, increases linearly with the jerk duration.
28
Kociubiński, Andrzej, Aleksandra Wilczyńska, Paweł A. Mazurek, Dominika Pigoń-Zając, Teresa Małecka-Massalska, and Monika Prendecka-Wróbel. "Impedance Measurement for the Monitoring of In Vitro Cells Cultured in the Presence of Electromagnetic Waves." Applied Sciences 13, no. 3 (January 17, 2023): 1267. http://dx.doi.org/10.3390/app13031267.
Повний текст джерелаАнотація:
This paper explores the possibility of using the impedance measurement method used to monitor morphological changes in culture cells for use in cultures in the presence of an electromagnetic field generated by a mobile phone. For this purpose, we used Electric Cell–Substrate Impedance Sensing (ECIS), which is a real-time, label-free, impedance-based method to study cell behaviors in tissue culture. As part of the work, a device enabling the connection in a climatic chamber was prepared without the need to interfere with environmental conditions, and a test culture of mouse fibroblasts was performed. The device based on the Arduino UNO programmable platform worked like a mobile phone. During cell proliferation, it was connected to the device three times and a change in electrical parameters in the measuring system was observed. During the phone call, there was a clear change in the values of the measured parameters. However, analysis of the obtained results indicated that there was little or no effect of the presence of the electromagnetic field on the cell culture, while the observed changes in the values of impedance, resistance, and capacitance are most likely due to the separation of positive and negative medium ions in the electromagnetic field. The application of the presented method seems possible; however, in order to eliminate the separation of ions, a different type of antenna should be designed to emit a homogeneous field to the entire well.
29
Waindok, Andrzej, and Paweł Piekielny. "Transient Analysis of a Railgun with Permanent Magnets Support." Acta Mechanica et Automatica 11, no. 4 (December 1, 2017): 302–7. http://dx.doi.org/10.1515/ama-2017-0046.
Повний текст джерелаАнотація:
Abstract The calculation and measurement results of transients for an electrodynamic accelerator with permanent magnet support have been presented in this paper. The calculations have been made using the magnetostatic model in the Maxwell software, as well as using a Matlab/Simulink transient model. The waves of mechanical parameters (projectile velocity and acceleration, force) and electric ones (excitation current and capacitor voltage) have been analyzed for different supply conditions (voltage value, capacitance). The efficiency and projectile energy have been studied as well. The mathematical models have been verified experimentally using the original laboratory stand. A good conformity between calculation and measurement results has been obtained.
30
Sener, Ummu S., and Sebahattin Eker. "Nondestructive Approach for Complex-Shaped Cracks in Concrete Structures by Electromagnetic Waves with FDTD Technique." Mathematical Problems in Engineering 2021 (June 1, 2021): 1–14. http://dx.doi.org/10.1155/2021/6624982.
Повний текст джерелаАнотація:
Concrete cracks have no specific shape and do not show linearity. Since the natural occurrences of concrete cracks make simulation identification difficult, rectangular step function and a dynamic geometry are used to define a concrete surface crack in the natural process. A novel interior crack expression is obtained by accepting the area between two curves as a crack filled by air in concrete and modeling this area like a Riemann integral domain. Taking the partition of this integral domain, the most realistic definition of the crack is made. Electromagnetic (EM) waves are utilized for numerical simulation after identifying the defects, cracks, rebars, and geometry of concrete. Three different simulation setups with complex geometries with two different surface cracks and one internal crack are simulated using a finite-difference time-domain (FDTD) method with Gaussian pulse wave excitation. Simulations are obtained using both transverse electric (TEz) waves and transverse magnetic (TMz) waves and the results are compared with each other. Air-dried concrete specimens are molded following simulation setups with surface cracks and measurements are made nondestructively with a Vivaldi antenna array in the frequency range of 0.4–4.0 GHz. The reflection and transmission coefficients are validated by comparing the data obtained using the measurement with the results obtained from numerical simulation.
31
Lüling, Martin G. "The paradox of anisotropy in electric logging: A simple proof and extensions to other physics domains." GEOPHYSICS 78, no. 1 (January 1, 2013): W1—W8. http://dx.doi.org/10.1190/geo2012-0123.1.
Повний текст джерелаАнотація:
Resistivity measurements in vertical wells through horizontally laminated formations suffer the paradox of anisotropy. In a borehole with negligible diameter, the measurement will only read the horizontal resistivity parallel to the laminae: It will be completely blind to the vertical resistivity perpendicular to the laminae, even though the source and sensor electrodes are vertically aligned. Coulomb’s law in anisotropic media explains this counterintuitive phenomenon. The anisotropy changes the Pythagorean distance to a new, anisotropic distance, which includes the inverse conductivity tensor. The mixed units of this anisotropic distance are reconciled in Coulomb’s law, whose normalization replaces the electric conductivity by the square root of the conductivity-tensor determinant. The special case of horizontal laminae and vertically aligned source and observation points simplifies Coulomb’s law in anisotropic media. The vertical conductivity can be extracted from the anisotropic distance as multiplicative factor, which then cancels a corresponding term in the normalization determinant. Any electrode-resistivity measurement can then be described as superposition of point sources and sensors. The analysis of Coulomb’s law in anisotropic media carries over to other physics domains with similar, close-form solutions: Compressional waves with anisotropic bulk modulus, thermal flow with anisotropic thermal conductivity, and fluid flow in porous media with anisotropic hydraulic permeability all are generalizations of the field equation in the anisotropic medium. Each physics domain introduces its own anisotropic distance.
32
Rehman, Ali, Zeeshan Najam Khan, Muhammad Siddique, Muhammad Shahzad, Makhdoom Muhammad Naeem, and Majid Hussain. "An Artificial Intelligence Based Current Measurement Technique in High Voltage Power Transmission and Distribution Lines using Pyro-Sensors." Pakistan Journal of Engineering and Technology 4, no. 2 (June 28, 2021): 94–99. http://dx.doi.org/10.51846/vol4iss2pp94-99.
Повний текст джерелаАнотація:
High voltage transmission lines are the fundamental element in order to transfer electricity from the power plant/grid to consumers. The frequency, current and voltage are the key figures to sustain the absolute quality of the power transmission, and maintaining such high performance requires smart solutions and equipment like Current Transformer (CT) & Potential Transformer (PT). This proposed work enlightens an inception to monitor current in the high voltage transmission lines by using pyro-sensors, machine learning (ML) techniques and artificial intelligence (AI). Using pyro-sensors around the transmission/distribution lines, data will be gathered about the heat waves (infrared waves) generated by the electric current in the transmission/distribution line. The proposed methodology uses this data to be processed by neural network based artificial intelligent algorithm to evaluate the amount of current in the transmission line. The claim about the authenticity of the proposed technique is tested and verified by MATLAB simulation neural network toolbox.
33
Tsuburaya, Tomonori, Zhiqi Meng, and Takashi Takenaka. "Inverse Scattering Analysis from Measurement Data of Total Electric and Magnetic Fields by Means of Cylindrical-Wave Expansion." Electronics 8, no. 4 (April 10, 2019): 417. http://dx.doi.org/10.3390/electronics8040417.
Повний текст джерелаАнотація:
Microwave tomography is an effective technique to estimate material distribution, where inverse scattering analysis is performed on the assumption that accurate information on the incident field is known for a measurement curve as well as in the target region. In reality, however, the information may often be unobtainable due to multiple scattering between the transmitting antenna and the target object, or existence of unwanted waves and obstacles. In this paper, a method to extract information on incident fields from measured total field data is proposed. The validity of the proposed method is verified on 2D TMz problems, where a cylindrical, a square, and an L-shape homogeneous object are employed as a target object. Furthermore, it is shown that the method is available even when there are unwanted obstacles outside the measurement curve.
34
Jayadipraja, Erwin Azizi. "ANALYSES OF RADIATION OF ELECTROMAGNETIC WAVES IN THE HIGH-VOLTAGE AIR DUCT (150 kV) CONSTRUCTION ON HEALTH." Public Health of Indonesia 3, no. 4 (November 30, 2017): 152–59. http://dx.doi.org/10.36685/phi.v3i4.143.
Повний текст джерелаАнотація:
Background: High-voltage air ducts is the government program to supply electricity needs. However, in practice, obstacles have been identified in the form of rejection from the community due to the outstanding issues that high-voltage air ducts have an impact on health.Aim: This research aims to analysis the magnitude of electromagnetic wave radiation of high-voltage air ducts construction on health.Methods: The study was conducted by measuring electromagnetic wave radiation prior to high-voltage air ducts (150 kV) construction and predicting the amount of radiation generated after this operation and its impact on health.Result: The field measurement result showed that the highest strength of magnetic field in the absence of construction and operation activity of high-voltage air ducts 150 kV was 0.00085 mT and the highest electric field was 0.004241251 V/m. The results of the magnetic field strength analysis showed that the highest strength of magnetic field and electric field when the high-voltage air ducts is completed and operated was magnetic field of 0.00415 mT and electric field of 38.4 V/m. The value was far lower than the standard limits recommended by IRPA / INIRC, WHO1990 and SNI 04-6950-2003. The allowed electric field strength is 5 kV / m and the allowed magnetic field strength is 0.1 mT.Conclusion: Electromagnetic wave radiation of High-Voltage Air Ducts is not exceeded the allowed limit, so it will not cause a direct risk to health.
35
Liu, Xiaowen, Lin Li, and Andrew J. Mason. "High-throughput impedance spectroscopy biosensor array chip." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 372, no. 2012 (March 28, 2014): 20130107. http://dx.doi.org/10.1098/rsta.2013.0107.
Повний текст джерелаАнотація:
Impedance spectroscopy is a powerful tool for characterizing materials that exhibit a frequency dependent behaviour to an applied electric field. This paper introduces a fully integrated multi-channel impedance extraction circuit that can both generate AC stimulus signals over a broad frequency range and also measure and digitize the real and imaginary components of the impedance response. The circuit was fabricated in a 0.5 μm complementary metal-oxide semiconductor. Tailored for cellular membrane interface characterization, the signal generator produces sinusoidal waves from 10 mHz to 10 kHz. To suit a variety of applications, the impedance extraction circuit provides a programmable current measurement range from 100 pA to 100 nA with a measured resolution of approximately 100 fA. Occupying only 0.045 mm 2 per measurement channel, the circuit is compact enough to include nearly 200 channels in a 3×3 mm 2 die area.
36
Pottelette, Raymond, and Matthieu Berthomier. "Nonlinear radiation generation processes in the auroral acceleration region." Annales Geophysicae 35, no. 6 (November 22, 2017): 1241–48. http://dx.doi.org/10.5194/angeo-35-1241-2017.
Повний текст джерелаАнотація:
Abstract. It is known from laboratory plasma experiments that double layers (DLs) radiate in the electromagnetic spectrum; but this is only known qualitatively. In these experiments, it was shown that the electron beam created on the high-potential side of a DL generates nonlinear structures which couple to electromagnetic waves and act as a sender antenna. In the Earth auroral region, observations performed by auroral spacecraft have shown that DLs occur naturally in the source region of intense radio emissions called auroral kilometric radiation (AKR). Very high time-, spatial-, and temporal-resolution measurements are needed in order to characterize waves and particle distributions in the vicinity of DLs, which are moving transient structures. We report observations from the FAST satellite of a localized large-amplitude parallel electric field (∼ 300 mV m−1) recorded at the edges of the auroral density cavity. In agreement with laboratory experiments, on the high-potential side of the DL, elementary radiation events are detected. They occur substantially above the local electron gyrofrequency and are associated with the presence of electron holes. The velocity of these nonlinear structures can be derived from the measurement of the Doppler-shifted AKR frequency spectrum above the electron gyrofrequency. The generated electron holes appear as the nonlinear evolution of electrostatic waves generated by the electron–electron two-stream instability because they propagate at about half the beam velocity. It is pointed out that, in the vicinity of a DL, the shape of the electron distribution gives rise to a significant power recorded in the left-hand polarized ordinary (LO) mode.
37
Yamamoto, K., I. Kawajiri, T. Tanji, M. Hibino, and T. Hirayama. "Development And Applications Of Highly Precise Phase Measurement Technique Using Phase-Shifting Electron Holography." Microscopy and Microanalysis 5, S2 (August 1999): 948–49. http://dx.doi.org/10.1017/s1431927600018067.
Повний текст джерелаАнотація:
Today's information-oriented society requires high-density, high-quality magnetic recording media. For the development of such new recording materials, the quantitative observation of magnetic fine structures by electron holography is eagerly awaited. However, the magnetic fields around particles smaller than 50 nm have not been observed because they are too weak to be observed in the usual way. Here, we report a highly precise phase measurement technique, improved phase-shifting electron holography. Using this method, we observed weak electric and magnetic fields precisely. The precision of the reconstructed phase image was as good as 2π/300 rad.In phase-shifting electron holography, the phase images are reconstructed from a series of electron holograms whose interference fringes are shifted relative to one after another. The shifting of interference fringes is achieved by tilting the incident electron beam, which corresponds to shifting the initial phase of the incident electron waves in a specimen plane.
38
Jamlus, Mohd Hanafiah Mat, and Zainal Ambri Abdul Karim. "Attaining Soot Oxidation Temperature by Inductive Coils Exposed to Electromagnetic Waves." Applied Mechanics and Materials 564 (June 2014): 304–9. http://dx.doi.org/10.4028/www.scientific.net/amm.564.304.
Повний текст джерелаАнотація:
This paper presents the findings in attaining soot oxidation temperature by using carbon steel coils exposed to electromagnetic waves. Soot are unburned carbon product in the exhaust gases during the combustion of diesel fuel, which are subjected to stringent emission regulations due to its harmful properties. The unburned carbon can be oxidised by heating as after-treatment strategy but in order for the oxidation to occur, it would require a temperature of not less than 600°C. In the present work, eight heating elements made from various carbon steel coil sizes were exposed to electromagnetic waves in the microwave oven cavity which heats up the coils to the oxidation temperature. Electromagnetic waves heating utilises electromagnetic radiation to induce electric field in a conductive material that causes the material to be heated. The microwave oven used has a power rating of 1000 W, with a microwave range of 2450 Mhz. Measurement of coils temperature and exposure time to electromagnetic waves were recorded and analysed. The results showed that only the coils with bigger coil loop size, i.e. 20 mm and lowest number of turns, i.e. 10 turns attained the threshold temperature of 600°C, while smaller diameter coil would accelerate the rate of heating. The findings from the research work are significant facts in the future development of in-situ exhaust gas after treatment system in reducing soot emissions.
39
T W, Alhidayatuddiniyah, Siwi Puji Astuti, and Santy Handayani. "Data Logger Digital Berbasis ATmega 2560." Navigation Physics : Journal of Physics Education 1, no. 2 (January 16, 2020): 41–46. http://dx.doi.org/10.30998/npjpe.v1i2.198.
Повний текст джерелаАнотація:
In this research, a data logger has been created to record the measurement results of current and electric voltage from a solar power system and wind power. This study aims to make a current and voltage measurement data recorder automatically so that the data retrieval process is easier and more accurate. Data loggers have 10bit ADC accuracy and data can be stored in a Micro SD Card. Data recording by a data logger is done every 100 ms for twenty-four hours then the data is plotted. The results of seven days of collecting current and voltage data for solar power plants obtained graphs such as square waves with maximum voltage and current are 33 volts and 537 mA, for wind power systems the maximum voltage and current were 26 volts and 273 mA. The memory used to record for one day is 5.2MB so the data logger is able to measure the current and voltage of the power generation system and record the measurement data for twenty-four hours continuously
40
Lefeuvre, F., M. Parrot, J. L. Rauch, B. Poirier, A. Masson, and M. Mogilevsky. "Preliminary results from the MEMO multicomponent measurements of waves on-board INTERBALL 2." Annales Geophysicae 16, no. 9 (September 30, 1998): 1117–36. http://dx.doi.org/10.1007/s00585-998-1117-3.
Повний текст джерелаАнотація:
Abstract. The MEMO (MEsure Multicomposante des Ondes) experiment is a part of the INTERBALL 2 wave consortium. It is connected to a total of six electric and nine magnetic independent sensors. It provides waveforms associated with the measurement of two to five components in three frequency bands: ELF (5–1000 Hz), VLF (1–20 kHz), LF (20–250 kHz). Preliminary analyses of low and high resolution data are presented. The emphasis is put on the estimation of the propagation characteristics of the observed waves.VLF hiss emissions are shown to be mainly whistler mode emissions, but other modes are present. An accurate estimation of the local plasma frequency is proposed when the low L = 0 cutoff frequency is identified. AKR emissions observed just above source regions are studied. R-X and L-O modes are found: the first at the lowest frequencies and the second at the highest. Both propagate with wave normal directions weakly oblique or quasi-parallel to the Earth's magnetic field direction. Propagation characteristics are also determined for a (non-drifting) fine structure of AKR. There is no fundamental difference with structurless events. Nightside and dayside bursts of ELF electromagnetic emissions are presented. It is not clear whether the two emissions belong to the "lion roar" emissions or not.Key words. Magnetospheric physics (auroral phenomena; plasma waves and instabilities; instruments and techniques)
41
Xu, Chen Yan, Ikuo Ihara, Kohmei Kenzaki, and Manabu Takahashi. "Non-Contact Measurement of Nugget Size of Spot Welding Using Focused Air-Coupled Ultrasound." Applied Mechanics and Materials 83 (July 2011): 151–56. http://dx.doi.org/10.4028/www.scientific.net/amm.83.151.
Повний текст джерелаАнотація:
Spot welding is widely used in the various fields of engineering and industries. Since the size, shape and mechanical properties of a nugget which is a zone melted and re-solidified during welding are closely related to the strength of the welded structure, quantitative evaluations of them are strongly required. In this work, an air-coupled ultrasound technique with focused transducers has been used for non-contact measurements of spot welds of steel plates. One-dimensional scanning in transmission configuration using a pair of focused air-coupled ultrasonic transducers operating with tone burst waves at 0.3 MHz is performed to obtain the amplitude profile of the transmitted ultrasound through the nugget area of a spot weld. A simple method for determining the nugget size from the profile of the transmitted ultrasound is proposed. To verify the validity of the method, calibration samples which imitate spot welds having different sizes of nuggets are prepared and used for demonstrating nugget size determinations. In addition, the proposed method has been applied to evaluate several spot welds fabricated with different electric currents (5 kA – 9 kA).
42
Santolík, O., F. Němec, K. Gereová, E. Macúšová, Y. de Conchy, and N. Cornilleau-Wehrlin. "Systematic analysis of equatorial noise below the lower hybrid frequency." Annales Geophysicae 22, no. 7 (July 14, 2004): 2587–95. http://dx.doi.org/10.5194/angeo-22-2587-2004.
Повний текст джерелаАнотація:
Abstract. We report results of a systematic analysis of a large number of observations of equatorial noise between the local proton cyclotron frequency and the local lower hybrid frequency. The analysis is based on the data collected by the STAFF-SA instruments on board the four Cluster spacecraft. The data set covers their first two years of measurement in the equatorial magnetosphere at radial distances between 3.9 and 5 Earth radii. Inspection of 781 perigee passages shows that the occurrence rate of equatorial noise is approximately 60%. We identify equatorial noise by selecting data with nearly linearly polarized magnetic field fluctuations. These waves are found within 10° of the geomagnetic equator, consistent with the published past observations. Our results show that equatorial noise has the most intense magnetic field fluctuations among all the natural emissions in the given interval of frequencies and latitudes. Electric field fluctuations of equatorial noise are also more intense compared to the average of all detected waves. Equatorial noise thus can play a non-negligible role in the dynamics of the internal magnetosphere.
43
Waara, M., H. Nilsson, R. Slapak, M. André, and G. Stenberg. "Oxygen ion energization by waves in the high altitude cusp and mantle." Annales Geophysicae 30, no. 9 (September 3, 2012): 1309–14. http://dx.doi.org/10.5194/angeo-30-1309-2012.
Повний текст джерелаАнотація:
Abstract. We present a comparative study of low frequency electric field spectral densities and temperatures observed by the Cluster spacecraft in the high altitude cusp/mantle region. We compare the relation between the O+ temperature and wave intensity at the oxygen gyrofrequency at each measurement point and find a clear correlation. The trend of the correlation agrees with the predictions by both an asymptotic mean-particle theory and a test-particle approach. The perpendicular to parallel temperature ratio is also consistent with the predictions of the asymptotic mean-particle theory. At times the perpendicular temperature is significantly higher than predicted by the models. A simple study of the evolution of the particle distributions (conics) at these altitudes indicates that enhanced perpendicular temperatures would be observed over many RE after heating ceases. Therefore, sporadic intense heating is the likely explanation for cases with high temperature and comparably low wave activity. We observe waves of sufficient amplitude to explain the highest observed temperatures, while the theory in general overestimates the temperature associated with the highest observed wave activity, indicating that such high wave activity is very sporadic.
44
Li, Lin, and Hongliang Zheng. "Numerical simulation of ultrasonic heat meter by multiphysics coupling finite-element simulation software." Thermal Science 24, no. 5 Part B (2020): 3309–217. http://dx.doi.org/10.2298/tsci191106122l.
Повний текст джерелаАнотація:
Objective: To increase heat calculation accuracy, the numerical simulation of the ultrasonic heat meter is explored by multiphysics coupling. Methods: The COMSOL, a multiphysics coupling finite-element simulation software, is used to build the coupling model of the sound field, structure field, and electric field. The propagation of ultrasonic waves in heat meters is simulated, and its sound field distribution in pure water is analyzed. According to the operating conditions of ultrasonic heat meters, the influence of impurities with different concentrations on ultrasonic propagation is analyzed. The end-face sound pressure levels of the incident transducer and the receiving transducer are compared to obtain the attenuation laws of ultrasonic waves in the liquid-solid two-phase flow. Results: The main lobe and multiple side lobes exist during the propagation of ultrasonic waves. The energy of the main lobe is higher than that of the side lobes. Bubbles resonate under the action of the sound field. Also, bubbles of different diameters correspond to different resonance frequencies, which have larger sound pressure than that of the incident sound field. Most of the sound waves are reflected at the liquid-solid interface, while some of them continue to propagate through the media, affecting the sound pressure distribution on the end-face of the receiving transducer, thereby affecting the measurement accuracy of the ultrasonic heat meter. Conclusion: The reliability and detection efficiency of the heat meter is improved, which is significant and theoretically valuable.
45
Yu, Hui Min. "Characteristics Analysis for the Spherical Antenna of a Seismometer." Advanced Materials Research 171-172 (December 2010): 458–61. http://dx.doi.org/10.4028/www.scientific.net/amr.171-172.458.
Повний текст джерелаАнотація:
A seismometer for vertical electric field component of natural ELF and ULF electromagnetic waves measurement by using spherical antenna is introduced. The goal of the proposed seismometer is to provide continuous observation of the natural electromagnetic emissions related to the coupling of seismic activity with the outer spaces and ionosphere, which utilize a spherical aluminum electrode 78mm in diameter with embedded enhanced preamplifier circuits that built to mount flush with the ground so as to preserve the configuration in which the antenna operates. The presented seismometer has a wide frequency response at low frequencies, it's typical sensitivity in the frequency range DC to 30MHz are shown to be and ,the dynamical range is >50dB in ELF and VLF and about 25dB in HF.
46
Yokoyama, T., M. Yamamoto, S. Fukao, T. Takahashi, and M. Tanaka. "Numerical simulation of mid-latitude ionospheric <i>E</i>-region based on SEEK and SEEK-2 observations." Annales Geophysicae 23, no. 7 (October 13, 2005): 2377–84. http://dx.doi.org/10.5194/angeo-23-2377-2005.
Повний текст джерелаАнотація:
Abstract. Observational campaigns of the mid-latitude ionospheric E-region with sounding rockets and ground-based instruments were conducted in 1996 (SEEK) and 2002 (SEEK-2). Both of them were successfully conducted to bring important findings about the mid-latitude E-region and quasi-periodic (QP) VHF radar echoes. The observational results in the SEEK and the SEEK-2 are compared with numerical simulations and discussed in this paper. While sporadic-E (Es)-layers are actually formed by the observed neutral wind, it is difficult for the constant wind shear to produce the sharp Es-layer gradient. However, once they are formed in the lower E-region, they cannot easily be dissipated by the simple diffusive motion. The polarization electric field, calculated under the condition at the rocket launch time, shows similar amplitude and structure to the measurement around the Es-layer altitude. The structure of the plasma density and the electric field above the Es-layer observed in the SEEK-2 showed a wave-like pattern up to an altitude of 150 km. Considering a mapping of the polarization electric field generated within the Es-layers, gravity waves are the possible source of the wave-like structure of the measured electric fields and sub-peaks of the electron density above the main Es-layers. Fluctuation of the measured magnetic field is reproduced by Hall or field-aligned current driven by the polarization electric field. The current theoretical models for QP echoes and the polarization electric field are basically verified by the discussion in this paper. Keywords. Ionospheric irregularities – Mid-latitude ionosphere – Numerical simulation studies
47
Shoimatussururoh and Bagus Dwi cahyono. "Pemeliharaan Lightning Arrester (LA) pada Gardu Induk Saketi 150kv di PT. PLN (Persero) ULTG Rangkasbitung." INSOLOGI: Jurnal Sains dan Teknologi 1, no. 5 (October 29, 2022): 520–31. http://dx.doi.org/10.55123/insologi.v1i5.869.
Повний текст джерелаАнотація:
Air transmission lines are very susceptible to lightning strikes resulting in traveling waves that can enter electrical equipment. Surge propagation can cause damage to existing electrical equipment on the transmission line of the substation. One component that has an important role in the substation is the Lightning Arrester (LA) as a protection system from lightning strikes. The purpose of this research is to determine the performance of lightning arresters that are more than 10 years old. Therefore, to ensure the safety of the electric power system from surge voltages and keep the lightning arrester performance reliable, it is necessary to carry out maintenance activities on the lightning arrester. The maintenance carried out is testing Leakage Current Measurement (LCM) and replacing lightning arresters. The research method used is the observation research method in the industrial field with interviews, data collection and analysis and literature study. The results of the LCM test on the old R phase lightning arrester are 112.7 A with a percentage of 86.69% in monitor conditions. So it is necessary to replace the old lightning arresters with new conditions. As for the results of the LCM test on the replacement R phase lightning arrester (new) of 33.4 A with a percentage of 25.69% in good condition.
48
Blum, Maren-Christina, Lilly Leydolph, and Sascha Klee. "Influence of electric field orientation on the effect of ocular current stimulation using full field electroretinogram." Current Directions in Biomedical Engineering 7, no. 2 (October 1, 2021): 167–70. http://dx.doi.org/10.1515/cdbme-2021-2043.
Повний текст джерелаАнотація:
Abstract Ocular current stimulation (CS) exhibits potential for the treatment of neurodegenerative ocular diseases. For a full field electroretinogram (ffERG) we found no CS effect on the characteristic waves (a-wave, b’-wave, and b-wave). To investigate whether the orientation of the generated electric field has an influence on the CS effect, this study repeated the previous ffERG study with changing one CS electrode position and compared the results of both studies. In the first study 15 (8 m, 27.5 ± 4.5 years) and in the second study 17 (7 m, 22.0 ± 1.9 years) healthy volunteers were stimulated with an anodal, cathodal, and sham direct CS of 800 μA for 5 min in three sessions (randomized, different days). For both studies, a cut-sized ring rubber electrode was placed around the eye. A square rubber electrode was placed for the first study at the ipsilateral temple and for the second study at the visual cortex. Before (ERG 1) and during (ERG 2) the CS, the ffERG was measured. For both studies, the difference between the ERG 1 and ERG 2 measurement (CS effect) for the three characteristic waves was analyzed and compared between the studies. For statistical analysis, the Mann-Whitney U test with Bonferroni correction was applied (α = 0.05). The comparison of the data distribution showed only slight differences between the studies. The Mann-Whitney U test found no significant difference of the CS effect between the studies for all amplitudes and CS groups (p ≥ 0.0055). In the mean, the latency differences were smaller than the time resolution, therefore no statements for latency effects were possible. It can be concluded that the retinal cells generating the ffERG are not affected by ocular CS in either electrode montages tested.
49
WATANABE, Kajiro, Yoshiro IEIRI, and Kazuyuki KOBAYASHI. "Absolute Speed Measurement of Moving Objects by Using the Spatial Pattern of Electric Field Intensity Due to the Fading of Electromagnetic Waves." Transactions of the Society of Instrument and Control Engineers 26, no. 11 (1990): 1223–29. http://dx.doi.org/10.9746/sicetr1965.26.1223.
Повний текст джерела
50
Brainin, Boris P., Alexey A. Veselov, Vladimir O. Lomakin, Konstantin G. Mikheev, and Alexey I. Petrov. "The Study of the Sound Waves Transmission along the Fluid Line through the TsN-2 Electric Pump." Izvestiya MGTU MAMI 16, no. 2 (January 18, 2023): 149–59. http://dx.doi.org/10.17816/2074-0530-109243.
Повний текст джерелаАнотація:
BACKGROUND: Noise at production site or at any other place where technical equipment operates is a huge issue. It has a strong negative effect on human nervous system, reduces average lifespan and causes a number of severe diseases. That is why reduction of noise, produced by pumps, is one of the current priorities of hydraulic engineering.
AIMS: In this study, the experimental research of sound transmission through an operating pump and a non-operating pump was carried out. The aim of the research is to find out, whether the last stage of a multistage pump is the main source of hydrodynamic noise (HDN) in pressure line (or the first stage in suction line), or all stages somehow contribute to HDN.
METHODS: The experiment was carried out on the TsN-2 two-stage impeller pump. In order to generate a sinusoidal signal, an imbedded generator, a vibration test rig and a power amplifier were used. Data acquisition for measurement of HDN and vibrations was performed with use of a conditioning amplifier, a hydrophone and an accelerometer. A 4-channel spectrum analyzer served as a device for processing the studied signal. In addition, a theoretical calculation, considering some physical assumptions, was carried out in order to obtain a more general and accurate concept.
RESULTS: After completing the experiment, hydrodynamic noise levels and differences for three cases were obtained. These cases are for the switched-on pump, the switched-off pump and for the pump with the removed stage. The data obtained with hydrophones (hydrodynamic noise levels) was correlated with the data obtained with accelerometers (vibration levels). As the correlated data analysis result, the sound insolation distribution over the spectrum was obtained.
CONCLUSIONS: According to the study results, it can be concluded that the absence of one of two stages ambiguously affected on the sound-insolation properties of the pump. Moreover, no firm conclusions can be drawn about the pump operation influence on the change in its sound-insolation properties.