Magnetic Field Meter Research Articles

EFEKTIVITAS MEDIA PEMBELAJARAN MAGNETIC FIELD METER BERBASIS ARDUINO UNTUK MENINGKATKAN HASIL BELAJAR FISIKA SISWA SMA/MA

The Effectiveness of Arduino-Based Magnetic Field Meter as Learning Media to Improve Physics Learning Outcomes of SMA/MA Students. This study aims to determine the effectiveness of Arduino-based magnetic field meter as learning media to improve physics learning outcomes for SMA/MA students. This research is an experimental research with one group pretest posttest research design. The sample of this research was 24 students of XII MIPA from one of the MA in Garut. Data were analyzed using the <g> calculation to determine the level of improvement in student learning outcomes. Based on the data analysis, the result of the calculation <g> was 0.9118, which means that the increase in student learning outcomes was in the high category. It can be concluded that the Arduino-based magnetic field meter as learning media is effective for improving student learning outcomes in magnetic field subject.

Frequency Response Extension of a Pulsed Magnetic Field Meter Based on an RL Integrator

Introduction. Measurements of the amplitude-time characteristics of pulsed magnetic fields are required in various research and technology areas. Such measurements are carried out during pulsed magnetic field immunity testing, with the magnetic field pulse rise time being hundreds of ns, and the pulse duration to its half initial value (halfdroop) being hundreds of µs.Aim. To develop a meter of magnetic field strength with a linear conversion characteristic for measuring the pulse rise time, the pulse duration to its half-droop, and the peak value of the pulsed magnetic field strength.Materials and methods. Among several available methods for measuring pulsed magnetic field parameters, the induction method was selected. To obtain a signal proportional to the pulsed magnetic field strength, a signal from the induction transducer is integrated using a self-integrating induction transducer (RL integration) or by using an external RC integrator. The former method shows good results when measuring signals with a duration of hundreds of ns; however, this method is inefficient when measuring the parameters of longer-duration pulses. The latter method is used to determine the parameters of signals with a duration of hundreds of µs and ms; however, this method gives a large error when measuring the parameters of signals with a duration of hundreds of ns and less. The consecutive use of the two integration methods leads to an additional error in the measurement of the pulse duration to its half-drop.Results. A setup for determining the required magnetic field pulse parameters using a pulse magnetic field meter based on an RL integrator was developed. The relative measurement errors comprised 10, 10, and 9 %, respectively. The developed setup eliminates the error caused by losses in the active resistance of an induction transducer, thus enabling the pulse duration to its half-droop to be measured without additional errors under the pulse rise time of hundreds of ns and the pulse droop time of hundreds of µs.Conclusion. The development of a functional converter made it possible to extend the frequency response of a pulsed magnetic field meter based on an RL integrator to the low-frequency region.

A calibration standard for low-frequency environmental magnetic field meters

In this paper, we present the establishment of a magnetic flux density standard in the national calibration laboratory in Croatia. A single-layer Helmholtz coil was constructed as a magnetic field source at frequencies from 25 Hz to 100 kHz to calibrate magnetic field meters up to field limits for occupational exposure. First, the calibration error margin was determined for probes up to 100 cm2 of the cross-sectional area with respect to the predefined calibration volume inside the coil. Next, the equivalent electrical model of the assembled standard was parameterized as a multiple resonance circuit to estimate the correction of the reference field with frequency. Finally, the calculated correction was experimentally verified using a single-turn induction loop with an amplifier. The resulting uncertainty budget of the standard confirms the laboratory's capability to calibrate environmental magnetometers with the best relative uncertainty of 0.8 %.

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.

Some algorithms related to the orientation of satellites and unmanned aerial vehicles

The stabilization of unmanned aerial vehicles and its orientation in a given direction is provided by the orientation system. One of the important stages in the development of UAV orientation systems is the development of object orientation algorithms. The problem of orientation of objects in the magnetic field is based on the estimation of the discrepancies between the model Bmod and the measured Bmeas components of the Earth's magnetic field. Accordingly, the paper discusses some algorithms related to the orientation of satellites and unmanned aerial vehicles. It is shown that limiting the model to the first 13 harmonics can lead to errors in the representation of the Earth's main magnetic field of about 15 nT. A mathematical proof of this fact is carried out based on the consideration of the equation of an ideal magnetic field meter. The work analytically proves that the Jacobian matrix of the magnetic field measurement vector in the earth's coordinate system has a determinant equal to zero, which means that, having knowledge of the magnetic field measurement vector H-1, it is impossible to uniquely determine the vector of the orientation angles of the meter {f, o, y }t-. Thus, the paper shows an algorithm for calculating the orientation angles depending on the values of the measured and model values of the Earth's magnetic field.

Electrical Compensation for Magnetization Distortion of Magnetic Fluxgate Current Sensor

Current sensors based on the fluxgate magnetic field meter and feedback zero-field operating principle have excellent current measurement accuracy and linearity in a large range of up to thousands of amperes. An excitation current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{e}$ </tex-math></inline-formula> ) is employed in a magnetic fluxgate sensor to magnetize the magnetic core periodically, which will generate magnetization distortion that affects the performance of the sensor. This article proposes a novel scheme for suppressing the magnetization distortion through electrical compensation. The source of the magnetization distortion is theoretically derived and analyzed. It is found that the magnetization distortion is a function of the excitation current <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{e}$ </tex-math></inline-formula> and is not affected by the primary current. Since <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{e}$ </tex-math></inline-formula> is a periodical current that is determined by the parameters of the sensor itself, it is feasible to inject a specified periodical current to the output port of the sensor to cancel the magnetization distortion. Compared with the magnetization distortion compensation method with an additional core and coil, this method does not need to pair the cores or coils, which significantly reduces the complexity of the production process and saves space for the sensor. A prototype sensor with electrical compensation is designed, fabricated, and tested. Experimental results show that the compensation setting significantly suppresses the magnetization distortion signal. The amplitude of the basic frequency component is reduced from 24 to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$6.8 ~\mu \text{V}$ </tex-math></inline-formula> . The other odd harmonics of the magnetization distortion are also reduced. The electrical compensation method works properly in a large current range from −1.5 to 1.5 kA. The scale accuracy of the prototype sensor is less than 5.7 ppm (parts per million). The compensation method can suppress the magnetization distortion to a similar level with operating temperature changes from room temperature to 50 °C.

Assessing the Health Risk Due to Exposure to Non-ionizing Radiation in the Form of Magnetic Field from Electrical Power Lines

We are all exposed to electromagnetic fields from electrical appliances, electric power transmission lines, distribution lines and power substations. This study was focused on investigating the possible risks to human health due to exposure to extremely low frequency varying magnetic fields from 330 kV, 132 kV, 33 kV and 11kV power lines in southeastern Nigeria. To determine the risks, a magnetic field meter was used to take measurements of magnetic flux from these power lines. From which, the induced current density due to exposure to varying magnetic fields was obtained using a model of the human body known as the prolate spheroid model. The maximum mean magnetic field and current density induced as obtained from the study were 4.790 µT and 0.04214 mA/m², which were obtained from the 330 kV power line. The study results are well below the reference levels of the International Commission for Non-Ionizing Radiation Protection, which are used for comparison, indicating that there is very low exposure risk to people living near these electric power transmission lines.

Prospective empirical test suite for energy practitioners

ObjectiveTo design a set of measures which were portable and cost-effective that scientists could use to determine competence of Energy Practitioners so that qualified practitioners could be employed in improving ongoing research accuracy. DesignThis was a prospective study with sample of convenience. Subjects213 subjects, 185 women and 28 men, were tested in this study. Outcome MeasuresEmpirical outcome measures included Triaxial Extra Low Frequency Magnetic Field meter, Data Logging Multimeter, RF Field Spectrum Analyzer, Acoustimeter, Broadcast Frequency counter, digital pH meter, digital TDS meter, GDV and physiology suite including heart rate variability, galvanic skin response, respiration, EMG, EKG, temperature and blood volume pulse. Additional questions on ethics and body reading were included in the test. ResultsResults suggest a range of tests which could be used to determine practitioner competence. Many of the energy practitioners tested consistently produced changes in the areas being measured past the error rate of the devices being used. Across the 13 measures, practitioner success ranged from 56.8% on the Acoustimeter to 100% on the Broadcast Frequency Counter measures with 95% CI. Tri Axial ELF magnetic field meter showed significance with practitioners producing oscillations of amplitude from the L hand at p< 0.01 with and effect size D of 1.5 and R hand p< 0.001 and an effect size D of 1.6. Practitioners demonstrated the ability to produce a change in pH beyond ±.1pH in 10 minutes at a Mean of 0.5 and a SD of 0.4 at a 95% CI of 0.48-0.58 and changes in TDS beyond+/-2% at a Mean of 36.7 and a SD of 35.2 at a 95% CI of 31.9-41.5. Other measures are discussed in detail. ConclusionsThis test presents a possible way to demonstrate a level of practitioner competence and improve the selection of energy practitioners for use in scientific studies of energy healing in the areas of full spectrum healing, laying-on-of-hands healing, Reiki, Qi Gong and Tai Chi.

Hand-Held Magnetic Field Meter Based on Colossal Magnetoresistance-B-Scalar Sensor

This paper describes a newly developed hand-held magnetic field meter, which enables the measurement of the magnitude of pulsed, alternating, or permanent magnetic flux density in a range from 0.06 up to 10 T. The device measures the magnitude of magnetic flux density independent of the field direction (B-scalar) and its measurement frequency ranges from dc to 100 kHz. This magnetometer consists of a hand-held magnetic field measurement meter and a pluggable probe whose main element is a spintronic sensor based on the colossal magnetoresistance (CMR) phenomenon. The new design of a probe containing a temperature sensor and a CMR-B-scalar sensor made from two manganite films with different resistivity versus temperature dependences ensures a reduced response signal dependence on temperature and thus increased the accuracy of the measurements. The hand-held meter has a graphical color touch screen for the display of the waveforms and provides measurements without the use of external oscilloscopes or other analog graphing devices. This magnetometer can be used for various industrial and scientific applications such as for the investigation of high-power electrical motors, fast high electrical current transients appearing in cases of the commutation of pulsed power circuits, for the measurement of pulsed magnetic fields in magnetic coils, or for measuring the dynamics of magnetic fields during electromagnetic metal forming and welding.

MONITORING THE AFR OF THE INFORMATION SIGNAL FILTER OF A FLUX-GATE MAGNETOMETER ON THE EXAMPLE OF A SINGLE LINK BUTTERWORTH FILTER

The content of this paper relates to the field of monitoring the parameters of a magnetic field (MF) meter with a MF a fluxgate sensor. The article directly discusses the control method for the amplitude frequency response (AFR) of the second harmonic filter of an EMF fluxgate meter. The purpose of the work is to minimize the workplace (WP) equipment for magnetometer monitoring. We suggest an AFR monitoring method based on three readings. As an input signal source, while monitoring an AFR filter, we suggest the use of a WP fluxgate meter. The fluxgate meter is installed in a magnetic screen. The method consists in generating the filter input signal using the magnetometer. The essence of the suggested method is to analyze the AFR symmetry. As the base filter, we use a second-order Butterworth filter with a narrowband symmetric AFR. The effect of the electrical element filter ratings is systematized in the form of a correspondence table: an electric element – an AFR parameter. We present the AFR sufficiency control analysis in terms of its symmetry. The AFR monitoring, in terms of its symmetry, has been supplemented with the Kр(f0) monitoring using the personal computer. We demonstrate the peculiarities of using a fluxgate meter as an input signal source. We derived the ratio of the magnetometer electronic part parameters that affect the accuracy (discreteness) of the filter’s input signal generation. We present an algorithm with a description of the magnetometer operation in the AFR monitoring mode.

Steel fiber confined graphite concrete for pavement deicing

Electric heating concrete is a specialized concrete containing electrically conductive components to attain stable conduction of electricity. Due to its electrical resistance, a thin electric heating concrete overlay can generate heat to prevent ice formation on a concrete roadway when connected to a power source.This electric heating concrete (EHC) deicing technology has been implemented in China at a large scale for the first time. Steel fibers and graphites had been used at conductive fillers in fabricating EHC. A 3.5-in. (9 cm) thick electric heating concrete layer was cast on the top of two existing parking ramps in Harbin. The East Ramp is 135 feet (41 m) long and 18.5 feet (5.6 m) wide and the North Ramp is 135 feet (41 m) long and 25 feet (7.6 m) wide, both having a steep slope of 15%. The overlay on each parking ramp was divided into 20 blocks.The electric heating concrete overlays were cast in place. Transformers converting 220 V AC to 48 V AC were used for the power source. Steel angle structural shapes were embedded in the electric heating concrete for electrodes. Some electric wires were pulled off from the electrodes during the construction. As a result, the power to a few blocks on each ramp was cut. A hand-held magnetic field meter was used to troubleshoot the disconnection locations. Based on measurements of the magnetic field strengths, all the disconnected wires in the hardened concrete were detected and reattached to the electrodes. The drilled holes were patched with carbon cement paste. Subsequent testing showed that good heating performance was successfully restored.

50 Hz pulse magnetic field measurements - metrological possibilities of magnetic field meters

50 Hz pulse magnetic field measurements - metrological possibilities of magnetic field meters

Method of standard field for LF magnetic field meter calibration

Abstract In this paper, a measurement system applied to calibrate LF (low frequency) magnetic field meters is described. The mechanism of generating a calculable standard LF magnetic field basing on circular Helmholtz coils is explained, than the measurement system is designed. The self-designed major components are introduced and their properties have been analyzed, several techniques are considered to improve the performance of the system. The sources of standard uncertainty related to calibration are analyzed, and the expanded uncertainty at 100 kHz is evaluated for example. In addition, the system is validated by comparing the calibration results with the results obtained by other laboratories.

AN INDUCTION SENSOR FOR MEASURING CURRENTS OF NANOSECOND RANGE

Purpose. A current meter based on the principle of electromagnetic induction is designed to register the current flowing in the rod lightning. The aim of the article is to describe the way of increasing the sensitivity of the converter by means of their serial communication. Methodology . The recorded current is in the nanosecond range. If compared with other methods, meters based on the principle of electromagnetic induction have several advantages, such as simplicity of construction, reliability, low cost, no need in a power source, relatively high sensitivity. Creation of such a meter is necessary, because in some cases there is no possibility to use a shunt. Transient properties of a meter are determined by the number of turns and the constant of integration. Sensitivity is determined by measuring the number of turns, the coil sectional area, the core material and the integration constant. For measuring the magnetic field pulses with a rise time of 5 ns to 50 ns a meter has turns from 5 to 15. The sensitivity of such a meter is low. When the number of turns is increased, the output signal and the front increase. Earlier described dependencies were used to select the main parameters of the converter. It was based on generally accepted and widely known equivalent circuit. The experience of created earlier pulse magnetic field meters was considered both for measuring the magnetic fields, and large pulse current. Originality. Series connection of converters has the property of a long line. The level of the transient response of the meter is calculated. The influence of parasitic parameters on the type of meter transient response is examined. The shown construction was not previously described. Practical value. The results of meter implementation are given. The design peculiarities of the given measuring instruments are shown.

Review of the Strain Modulation Methods Used in Fiber Bragg Grating Sensors

Fiber Bragg grating (FBG) is inherently sensitive to temperature and strain. By modulating FBG’s strain, various FBG sensors have been developed, such as sensors with enhanced or reduced temperature sensitivity, strain/displacement sensors, inclinometers, accelerometers, pressure meters, and magnetic field meters. This paper reviews the strain modulation methods used in these FBG sensors and categorizes them according to whether the strain of an FBG is changed evenly. Then, those even-strain-change methods are subcategorized into (1) attaching/embedding an FBG throughout to a base and (2) fixing the two ends of an FBG and (2.1) changing the distance between the two ends or (2.2) bending the FBG by applying a transverse force at the middle of the FBG. This review shows that the methods of “fixing the two ends” are prominent because of the advantages of large tunability and frequency modulation.

Examples of extremely low-frequency magnetic fields in a Finnish metro station

The aim of this pilot study was to present examples of extremely low-frequency (ELF) magnetic fields in a Finnish metro station. The metro trains are powered by 750 V DC voltage supplied through a conductor rail next to the running rails. We measured magnetic fields with a magnetic field meter MFM 3000 in 17 cases when a train was leaving the platform in the same metro station. The maximum measured magnetic field was 5400 nT (at 1 m height and 4.3 m from the conductor rail). The magnetic field stayed at this level for a very short time after the metro left the platform. It is possible that there are also DC magnetic fields near the metro as the train leaves the station because the trains are powered by DC voltage. Therefore, it is also important to measure DC fields and DC currents in the future.

Differential twin receiving fiber-optic magnetic field and electric current sensor utilizing a microfiber coupler.

A magnetic field and electric current meter is proposed based on a differential twin receiving microfiber coupler (MC) sensor. The sensor is fabricated by bonding a MC and an aluminium (Al) wire together. With the small diameter of several micrometers, the output power at each port of the coupler shows high sensitivity to the distortion of Al wire from the Lorentz force induced by the magnetic field or the thermal expansion caused by the electric current. The ratio of the difference to the sum of the output signals from the two output ports can be used to eliminate the variation in the sensitivity. Using our proposed sensor, we measured a magnetic field sensitivity of ~0.0496 mT(-1), current sensitivity of ~1.0899 A(-1) without any magnetic field, and good repeatability are also shown in this paper.

Correlation between exposure to magnetic fields and embryonic development in the first trimester.

ObjectiveTo explore the correlation between maternal magnetic field (MF) exposure in daily life and embryonic development.MethodsA cross-sectional study was conducted among 149 pregnant women who were seeking induced abortion of unwanted pregnancies. Participating women were asked to wear an EMDEX Lite magnetic field meter for a 24-h period to obtain MF exposure level within 4 weeks following the abortion. Embryonic bud and sac lengths were measured through B-mode ultrasound before the surgical abortion. Embryo sections were prepared and examined for histological changes, and the apoptosis status of the deciduas was examined using the TUNEL apoptosis assay.ResultsEmbryonic bud length was inversely associated with maternal daily MF exposure level; the association was statistically significant at the time-weighted-average and 75th percentile of MF exposure levels, with coefficients of −3.09 (P = 0.0479) and −3.07(P = 0.0228), respectively. Logistic regression for examining the risk of higher MF exposure indicated that women with her 75th percentile of daily MF measurements ≥0.82 mG had a 3.95-fold risk of having a fetus with a shorter embryonic bud length than those whose daily MF exposure were <0.82 mG. MF exposure was associated with a higher degree of apoptosis, but the association was not statistically significant. We failed to find a statistical correlation between MF exposure and embryonic sac length and histological changes in the first trimester.ConclusionPrenatal MF exposure may have an adverse effect on embryonic development.

Assessment of Ambient Magnetic Field Exposure Emitted from Underground Transmission Lines in Some Areas of Riyadh

The purpose of this work is to measure the magnetic emitted from underground transmission lines and camper with international limit. The measurements of magnetic field were performed with the aid of TRIAXIAL ELF Magnetic Field Meter. The level of magnetic field were found in the range 1 to 197 with mean value of 51.6 ± 44.2 mG. The survey of magnetic field measurements revealed that the level of radiation dose found to be far below than the standard dose limit for the public exposure set by the International Commission on Non-Ionizing Radiation Protection ICNIRP 830.

Magnetoencephalography: Basic principles.

Magnetoencephalography (MEG) is the measurement of the magnetic field generated by the electrical activity of neurons. It is usually combined with a magnetic resonance imaging to get what is called magnetic source imaging. The technology that has helped record these minute magnetic fields is super-conducting quantum interference detector which is like a highly sensitive magnetic field meter. To attenuate the external magnetic noise the MEG is housed inside a magnetically shielded room. The actual sensors recording magnetic fields are magnetometers and/or gradiometers. MEG fields pass through the head without any distortion. This is a significant advantage of MEG over electroencephalography. MEG provides a high spatial and temporal resolution. The recording and identification information should be according to the American Clinical Magnetoencephalography Society guidelines published in 2011. MEG currently has two approved indications in the United States, one is for pre-operative brain mapping and the other is for use in epilepsy surgery. MEG studies have shown functional brain tissue inside brain tumors.