Electric Field Meter Research Articles

Triboelectric surface field strength of wood after brushing

Mechanical friction causes electrical surface charges on wooden surfaces. In this research, triboelectric activation of solid wood surfaces was investigated by using a wood brushing machine. The extent of activation and the potential influence of machine parameters, or the influence of various wood species are questions so far unanswered. The electrical surface field strengths were continuously detected by means of an electric field meter. Machine settings, such as feed rate and brush pressure, have been varied to better understand the effects on the resulting surface charges. Data showed that nylon and tynex brushes lead to strong positive electric surface field strengths while natural fibers lead to less positive surface field strengths. In contrast, steel wire brushes showed negative electrical field strengths for oak wood, slightly positive field strengths for beech wood and stronger positive field strengths for softwoods. Overall, the tendency that a higher brush pressure led to higher recorded electrical surface field strengths while a faster feed rate reduced the field strengths was observed. As these findings were influenced by wood species and brushing materials, a better understanding of specific triboelectric interactions is essential for future applications. Tailoring surface charges can be an asset for new technical applications, such as chemistry-free primer treatments prior to wood coating.

Development of a portable device for preventing injuries due to a loss of grounding and broken neutral

Any discontinuity in the power cords of electrical devices can lead to electric shock, injury, and even death. This article presents a portable device that, when placed in the proximity of handheld tools, prevents such injuries. The principal operation of this device is based on electric and magnetic field meters and display segment LEDs. When the grounding conductor of a portable tool with a metal enclosure is broken, the electric field around it is increased. In the same way, when the neutral conductor is broken, the magnetic field is increased. The device detects any variations in electric or magnetic fields and displays a warning signal for alert.

南京地区大气电特征及电场仪预警效果的分析研究

南京地区大气电特征及电场仪预警效果的分析研究

Fair weather electric field meter for atmospheric science platforms

A miniature field meter is described for measuring fair weather electric fields (of magnitude ~100 Vm-1). It is a brushless field mill constructed from machine-cut parts, driven by a computer fan motor. It resolves fair weather fields at ~1 mV per (Vm−1), with a time response of 0.65 s. It implements self-calibration through combining a mechanical shutter with a programmable bipolar calibration electrode. It has a mass of 86 g, dimensions 4 cm × 4 cm x 8 cm and consumes <100 mA at 6 V. This design will facilitate new climate-related measurements using balloons and remotely piloted aircraft.

Investigation of ecogeophysical factors of the environment of Vladikavkaz

A study of ecogeophysical factors of the environment in Vladikavkaz was carried out at 126 points: indicators of noise pollution, electric fields and the level of gamma radiation were measured. The noise level was determined with the help of noise and vibration meter Ekogeofizika-110A of the domestic company Oktava. It has been defined that the population of Vladikavkaz is subjected to a significant noise period of time, which exceeds the permissible level, which can negatively affect the health of citizens. Measurements of gamma radiation level were made using a gamma radiation dosimeter DBGA-OCHA. According to the obtained data, the population of Vladikavkaz is exposed to the gamma radiation in the range of 0.05–0.18 µSv/h and with an average value of 0.11 µSv/h, which is below the maximum permissible level. In order to study the electric fields, the measurements were carried out by the electric field meter IEP-05. The electric field strength reached up to 1400 V/m at individual measurement points, at an acceptable level of 800 V/m; this indicator exceeds the maximum permissible values.

On the Triggering Mechanisms of Upward Lightning

Upward lightning studies took place in Rapid City, South Dakota, USA and S. Paulo, Brazil during the summer thunderstorm seasons from 2011 to 2016. One of the main objectives of these campaigns was to evaluate and characterize the triggering of upward positive leaders from tall objects due to preceding nearby flash activity. 110 upward flashes were observed with a combination of high- and standard-speed video and digital still cameras, electric field meters, fast electric-field antenna systems, and for two seasons, a Lightning Mapping Array. These data were analyzed, along with correlated lightning location system data, to determine the triggering flash type responsible for the initiation of upward leaders from towers. In this paper, we describe the various processes during flash activity that can trigger upward leaders from tall objects in the USA and in Brazil. We conclude that the most effective triggering component is the propagation of the in-cloud negative leader during the continuing current that follows a positive return stroke.

Inversion of a Thunderstorm Cloud Charging Model Based on a 3D Atmospheric Electric Field

The measurement of the atmospheric electric field is of great significance for the study of thunderstorm cloud charge models. Traditional electric field meters can only measure the vertical component of the atmospheric electric field, and thus it is difficult to invert the structure of the thunderstorm cloud. A three-dimensional atmospheric electric field meter was developed to simultaneously measure the horizontal and vertical components of the atmospheric electric field in this paper. The effective measurement linearly relates the measured electric field to the induced voltage, and the nonlinear equations of the three-dimensional atmospheric electric field and the thunderstorm cloud-charging model parameters were derived. The particle swarm optimization algorithm (PSO) and the three-dimensional atmospheric electric field were used to invert the thunderstorm clouds. Experimental observations of the three-dimensional electric field in a cloud during a thunderstorm were analyzed. Combined with the typical charged structure model, parameters such as the charge and relative distance of the thunderstorm cloud were determined. The results showed that the value of the inversion fitness function reached 0.7288, and the charge structure was even. The measurement of the three-dimensional atmospheric electric field provides a new means of observation for the study of atmospheric electricity.

Calibration of electric field data of DEMETER satellite

ABSTRACTIn this paper, based on the data measured by the space-borne ICE (Instrument Champ Electrique) electric field meters of the DEMETER (Detection of Electro-Magnetic Emission Transmitted from Earthquake Regions) satellite, the induced electric fields generated by the electric antennas of ICE when they cut the Earth’s geomagnetic lines during the satellite’s motion are computed, and the electrostatic field data in the range of ultra low frequency (ULF: f < 3 kHz) are calibrated. The numerical results indicate that the induced electric fields generated by the electric antennas of the space-borne electric field meters account for a considerable proportion among the data of electric fields measured by the DEMETER satellite. Besides, a more conspicuous regularity is presented as the magnitude of the modified electric fields varies with the Earth’s latitudes and longitudes.

An atmospheric electric field meter

The Ryabina atmospheric electric-field meter is described. Results of its comparative tests are presented, which demonstrate that it is superior to its foreign analog, that is, the EFM550 electric-field meter (from Vaisala, Finland), in a number of parameters. The dynamic range of the meter is ±30 000 V/m, the discreteness of measurable values is 1 V/m, and the measurement rate is 10 s–1.

An overview of the 29 May 2012 Kingfisher supercell during DC3

AbstractOn 29–30 May 2012, the Deep Convective Clouds and Chemistry experiment observed a supercell thunderstorm on the southern end of a broken line of severe storms in Oklahoma. This study focuses on an approximately 70 min period during which three mobile Doppler radars operated and a balloon‐borne electric field meter, radiosonde, and particle imager flew through the storm. An overview of the relationships among flash rates, very high frequency (VHF) source densities, and Doppler‐radar‐derived storm parameters is presented. Furthermore, the evolution of the flash distribution relative to the midlevel storm's kinematics and microphysics is examined at two times during a period of rapid storm intensification. The timing of increases in VHF counts in the 8–10 km above ground level (agl) layer, which contained the largest VHF source counts, is similar to the timing of increases in updraft mass flux, in updraft volume, and in graupel volume at approximately 5–9 km agl. Although some increases in VHF source counts had little or no corresponding increase in one or more of the other storm parameters, at least one other parameter had an increase near the time of every VHF increase, a pattern which suggests a common dependence on updraft pulses, as expected from the noninductive graupel‐ice electrification mechanism. A classic bounded weak lightning region was observed initially during storm intensification, but late in the period it appeared to be due to a wake in the flow around the updraft, rather than due to a precipitation cascade around the updraft core as is usually observed.

A measurement method for atmospheric ion mobilities based on cylindrical electrodes in direct current corona discharge

Ion mobility is one of fundamental parameters to describe the motion of ions in an electric field and a significant quantity to calculate the ionized field and ion current density of ultrahigh‐voltage direct current (UHVDC) power lines. This paper presents a measurement method for atmospheric ion mobilities in a DC corona discharge. An apparatus with coaxial cylindrical electrodes is designed and utilized. A vibrating electric field meter is employed to measure the ionized field of the electrode. Experimental results show that under atmospheric conditions, the average positive and negative ion mobilities are 1.76 × 10−4 and 1.88 × 10−4m2·V−1·s−1, respectively. The proposed method is compared with previous works of others. The impact of fluctuations of the measured ionized field and ion current density on the results of ion mobilities is also analyzed. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley &amp; Sons, Inc.

Impact of Space Charges From Direct Current Corona Discharge on the Measurement by the Rotating Electric-Field Meter

The ionized field is one of significant parameters to evaluate the electromagnetic environment of ultra-high-voltage direct current (UHVDC) transmission lines. The field mill is usually utilized to measure the ionized field on the ground level under the UHVDC power lines. In order to investigate the distortion characteristics of the ionized field with the presence of spaces charges near the probe of the field mill, Poisson's equation and current continuity equation are solved, respectively, based on the finite-element method and Gauss's law in the cylindrical coordinate system. The ionized fields on the surface of the probe are calculated under different ion current densities. An experimental apparatus with corona wire net and ground plate is designed and used to measure the ionized field and ion current density. Experimental results have shown that the measured data are consistent with the calculated ones, which verify the validity of the algorithm presented. The impact of the space charges on the field mill may provide valuable reference for the measurement of the electromagnetic environment of UHVDC projects.

Design and implementation of a low-cost prototype system for continuous monitoring of electric fields generated by mobile base stations in the 850 MHz and 1900 MHz frequency bands

This paper describes the development of a scalable, autonomous and inexpensive monitoring system of electric fields generated by mobile phone base stations in the 850 MHz and 1900 MHz frequency bands, in Peru. The developed system is scalable because it consists of a ZigBee wireless network with electric field strength sensor and repeater nodes in a mesh topology with a dynamic routing mechanism. Sensor and repeater nodes are autonomous because they get their power from a small photovoltaic system. All electronic circuits were developed using low-cost technology. To manage the system elements and to store the information captured by the sensors, a web platform was developed. Tests in laboratory and field were performed to assess the accuracy of the sensor node. For this, a calibrated isotropic Narda SRM 3000 electric field meter was used. The results were very satisfactory for 1900 MHz frequency band but not for 850 MHz; some recommendations are given to improve the accuracy in the latter case. The performance of the sensor node's photovoltaic system was also assessed through the monitoring of the continuity of the system operation over time. It was verified that the sensor node was kept operating continuously without failures during a three-month test.

First results of atmospheric electricity measurements by CS110 electric field meter at Paratunka observatory, Kamchatka

The results of continuous measurements of AEF potential gradient by CS110 fluxmeter at Paratunka observatory are presented.

Long‐duration X‐ray emissions observed in thunderstorms

AbstractIn 1995, a series of four balloon flights with an X‐ray spectrometer and an electric field meter were conducted to examine if strong electric fields could accelerate, and perhaps multiply, cosmic ray secondary electrons and produce bremsstrahlung X‐rays. X‐ray intensities between 10 and 1000 times that of normal background were observed in conjunction with strong electric fields. Both negative and positive polarity electric fields (as referenced to the vertical field) produced X‐rays, which lasted for time scales on the order of tens of seconds. It was also observed that the increased X‐ray intensity would return to near background levels after lightning reduced the local electric field. The observations indicate that X‐rays observed above background are most likely produced by a runaway electron process occurring in the strong static electric field present in thunderstorms. The production of runaway electrons can occur over long periods of time without causing an electrical breakdown. This may provide a leakage current that limits the large scale electric field to values near the runaway threshold, especially in regions where the thunderstorm charging rate is low.

Coordinated lightning, balloon‐borne electric field, and radar observations of triggered lightning flashes in North Florida

AbstractThis study examines coordinated storm and triggered lightning observations made in July–August 2013 at the International Center for Lightning Research and Testing to determine why triggered flashes in Florida typically transition from an upward vertical channel entering the cloud to horizontal structure near the storm's melting level. Data from a balloon‐borne electric field meter, a mobile 5 cm wavelength radar, and a small‐baseline VHF Lightning Mapping Array acquired during a period in which three flashes were triggered on 1 August confirmed the hypothesis that the transition to horizontal lightning structure just above the melting level occurred in a layer of negative charge. This experiment was the first to provide vertical profiles of the electric field in Florida storms, from which their vertical charge distribution could be inferred. Three dissipating storms observed on different days all had negative charge near the melting level, but a growing mature storm had positive charge there.

All Sky Camera, LIDAR and Electric Field Meter: Auxiliary instruments for the ASTRI SST-2M prototype

ASTRI SST-2M is the end-to-end prototype telescope of the Italian National Institute of Astrophysics, INAF, designed to investigate the 10–100 TeV band in the framework of the Cherenkov Telescope Array, CTA. The ASTRI SST-2M telescope has been installed in Italy in September 2014, at the INAF observing station located at Serra La Nave on Mount Etna. The telescope is foreseen to be completed and fully operative in spring 2015 including auxiliary instrumentation needed to support both operations and data analysis. In this contribution we present the current status of a sub-set of the auxiliary instruments that are being used at the Serra La Nave site, namely an All Sky Camera, an Electric Field Meter and a Raman Lidar devoted, together with further instrumentation, to the monitoring of the atmospheric and environmental conditions. The data analysis techniques under development for these instruments could be applied at the CTA sites, where similar auxiliary instrumentation will be installed.

Measurements of Electric and Magnetic Field Intensities at 50 Hz Mains Frequency and Comparison of Measurement Results to ICNIRP’s Reference Levels for General Public Exposure

International Commission on Non-Ionizing Radiation Protection (ICNIRP) accepted by many countries as well as Turkey is a commission which determines reference levels for general public and occupational exposure to electromagnetic fields and has intensive works on these issues. ICNIRP has published separately a low frequency band (0-100 kHz) and a high frequency band (100 kHz-300 GHz) guidelines which investigate the biological and potential health hazard effects of electric, magnetic and electromagnetic fields. In this study, measurements of low frequency electric and magnetic fields were taken in 30 different locations in the city center of Diyarbakir. Some locations exceeding the reference levels for general public exposure specified by ICNIRP were determined in the measurements of low frequency electric and magnetic fields and then some assessments were made about them. Low frequency electric and magnetic field meter device which is named EHP-50C was used in the measurements. The measurement results were calculated as an average value of 6 minute measurements. In addition, under a high voltage power line during 60 minutes, electric and magnetic field intensity values were recorded in the same manner. As a result of recordings, changes in the electric and magnetic field intensity values were observed, and then these changes were shown on the charts.

A Solvatochromic Model Calibrates Nitriles’ Vibrational Frequencies to Electrostatic Fields

Electrostatic interactions provide a primary connection between a protein's three-dimensional structure and its function. Infrared probes are useful because vibrational frequencies of certain chemical groups, such as nitriles, are linearly sensitive to local electrostatic field and can serve as a molecular electric field meter. IR spectroscopy has been used to study electrostatic changes or fluctuations in proteins, but measured peak frequencies have not been previously mapped to total electric fields, because of the absence of a field-frequency calibration and the complication of local chemical effects such as H-bonds. We report a solvatochromic model that provides a means to assess the H-bonding status of aromatic nitrile vibrational probes and calibrates their vibrational frequencies to electrostatic field. The analysis involves correlations between the nitrile's IR frequency and its (13)C chemical shift, whose observation is facilitated by a robust method for introducing isotopes into aromatic nitriles. The method is tested on the model protein ribonuclease S (RNase S) containing a labeled p-CN-Phe near the active site. Comparison of the measurements in RNase S against solvatochromic data gives an estimate of the average total electrostatic field at this location. The value determined agrees quantitatively with molecular dynamics simulations, suggesting broader potential for the use of IR probes in the study of protein electrostatics.

Probing ultrafast charge separation at organic donor/acceptor interfaces by a femtosecond electric field meter

Charge separation at organic donor/acceptor interfaces is a key step in the functioning of an organic photovoltaic cell, but experimental techniques that uniquely probe the interface on ultrafast time scales are absent. Here, we apply a technique sensitive to interfacial charge separation based on four-wave mixing to follow the transient electric field at the donor/acceptor interface. Examining the model system of copper phthalocyannine (CuPc) and fullerene (C60) bilayers, we observe ultrafast electron transfer from photoexcited CuPc to C60 on a 80 ± 20 fs time scale.