Analysis of Arguments Constructed by First-Year Engineering Students Addressing Electromagnetic Induction Problems

ERIC Educational Resources Information Center

Almudi, Jose Manuel; Ceberio, Mikel

2015-01-01

This study explored the quality of arguments used by first-year engineering university students enrolled in a traditional physics course dealing with electromagnetic induction and related problem solving where they had to assess whether the electromagnetic induction phenomenon would occur. Their conclusions were analyzed for the relevance of the…

The Search for Electromagnetic Induction (1820-1831). Experiment No. 20.

ERIC Educational Resources Information Center

Devons, Samuel

This paper focuses on the search for electromagnetic induction from 1820 to 1831 and the efforts by Augustin Fresnel's colleague, Andre Marie Ampere, in electric and magnetic induction. Faraday's work is discussed with excerpts from his diary on electromagnetism. A variety of different experiments by researchers including Francoise Jean Arago,…

AC induction field heating of graphite foam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klett, James W.; Rios, Orlando; Kisner, Roger

A magneto-energy apparatus includes an electromagnetic field source for generating a time-varying electromagnetic field. A graphite foam conductor is disposed within the electromagnetic field. The graphite foam when exposed to the time-varying electromagnetic field conducts an induced electric current, the electric current heating the graphite foam. An energy conversion device utilizes heat energy from the heated graphite foam to perform a heat energy consuming function. A device for heating a fluid and a method of converting energy are also disclosed.

Electromagnetic Remote Sensing. Low Frequency Electromagnetics

DTIC Science & Technology

1989-01-01

biased superconducting point - contact quantum devices", J.Appl.Phys. 41, p.1572, 1970. [40] A.Yariv and H.Winsor, "Proposal for detection of magnetic ... magnetics , electromagnetic induc- tion, electrostatics) 2. Nondestructive testing (electromagnetic induction, neutron tomography, x-ray imaging) 3...Detection of submarines from aircraft or ships ( magnetics , electromagnetic induction) 4. Detection of land vehicles using buried sensors ( magnetics

Preliminary design of a Primary Loop Pump Assembly (PLPA), using electromagnetic pumps

NASA Technical Reports Server (NTRS)

Moss, T. A.; Matlin, G.; Donelan, L.; Johnson, J. L.; Rowe, I.

1972-01-01

A preliminary design study of flight-type dc conduction-permanent magnetic, ac helical induction, and ac linear induction pumps for circulating 883 K (1130 F) NaK at 9.1 kg/sec (20 lb/sec) is described. Various electromagnetic pump geometrics are evaluated against hydraulic performance, and the effects of multiple windings and numbers of pumps per assembly on overall reliability were determined. The methods used in the electrical-hydraulic, stress, and thermal analysis are discussed, and the high temperature electrical materials selected for the application are listed.

Finite Element Analysis in the Estimation of Air-Gap Torque and Surface Temperature of Induction Machine

NASA Astrophysics Data System (ADS)

Mr., J. Ravi Kumar; Banakara, Basavaraja, Dr.

2017-08-01

This paper presents electromagnetic and thermal behavior of Induction Motor (IM) through the modeling and analysis by applying multiphysics coupled Finite Element Analysis (FEA). Therefore prediction of the magnetic flux, electromagnetic torque, stator and rotor losses and temperature distribution inside an operating electric motor are the most important issues during its design. Prediction and estimation of these parameters allows design engineers to decide capability of the machine for the proposed load, temperature rating and its application for which it is being designed ensuring normal motor operation at rated conditions. In this work, multiphysics coupled electromagnetic - thermal modeling and analysis of induction motor at rated and high frequency has carried out applying Arkkio’s torque method. COMSOL Multiphysics software is used for modeling and finite element analysis of IM. Transient electromagnetic torque, magnetic field distribution, speed-torque characteristics of IM were plotted and studied at different frequencies. This proposed work helps in the design and prediction of accurate performance of induction motor specific to various industrial drive applications. Results obtained are also validated with experimental analysis. The main purpose of this model is to use it as an integral part of the design aiming to system optimization of Variable Speed Drive (VSD) and its components using coupled simulations.

Application of Electromagnetic Induction Technique to Measure the Void Fraction in Oil/Gas Two Phase Flow

NASA Astrophysics Data System (ADS)

Wahhab, H. A. Abdul; Aziz, A. R. A.; Al-Kayiem, H. H.; Nasif, M. S.; Reda, M. N.

2018-03-01

In this work, electromagnetic induction technique of measuring void fraction in liquid/gas fuel flow was utilized. In order to improve the electric properties of liquid fuel, an iron oxide Fe3O4 nanoparticles at 3% was blended to enhance the liquid fuel magnetization. Experiments have been conducted for a wide range of liquid and gas superficial velocities. From the experimental results, it was realized that there is an existing linear relationship between the void fraction and the measured electromotive force, when induction coils were connected in series for excitation coils, regardless of increase or decrease CNG bubbles distribution in liquid fuel flow. Therefore, it was revealed that the utilized method yielded quite reasonable account for measuring the void fraction, showing good agreement with the other available measurement techniques in the two-phase flow, and also with the published literature of the bubbly flow pattern. From the results of the present investigation, it has been proven that the electromagnetic induction is a feasible technique for the actual measurement of void fraction in a Diesel/CNG fuel flow.

Joseph Henry’s role in the discovery of electromagnetic induction

NASA Astrophysics Data System (ADS)

Smith, Glenn S.

2017-01-01

The discovery of electromagnetic induction in the early part of the 19th century is one of the greatest scientific achievements of all time, and it has had tremendous technological consequences. The credit for this discovery rightfully goes to the great English experimental physicist Michael Faraday. However, the American physicist Joseph Henry made some observations comparable to Faraday’s at nearly the same time, and for that reason, Faraday and Henry are often considered to be co-discoverers of some aspects of electromagnetic induction. We examine Henry’s early research on electromagnetism, starting from his efforts to improve the electromagnet, which led directly to his investigations of induction. We describe his earliest experiments on both mutual and self-induction, and pay particular attention to the relationship of Henry’s research to that of Faraday. The approach is one in which the experiments are described and then analysed using modern theory and terminology.

High speed displacement measurement based on electro-magnetic induction applied to electromagnetically driven ring expansion

NASA Astrophysics Data System (ADS)

Han, Xiaotao; Wu, Jiawei; Huang, Lantao; Qiu, Lei; Chen, Qi; Cao, Quanliang; Herlach, Fritz; Li, Liang

2017-11-01

Investigating the mechanism of electromagnetic forming (EMF) becomes a hot topic in the field of metal forming. The high speed up to 200 m/s in EMF makes it a real challenge to capture the forming process. To this end, a new method for measuring displacement at high speed based on electromagnetic induction has been developed. Specifically this is used to measure the displacement of an expanding metal ring driven by a pulsed magnetic field; this is one of the basic EMF processes. The new method is simple and practical, and it combines high-speed response with adequate precision. The new measurement system consists of a printed circuit board (PCB) and a Rogowski probe. Eleven coaxial annular detecting probes are arranged in the PCB plate to acquire induced voltage at different positions, and a Rogowski probe is used to measure the current in the driving coil. The displacement of the ring is deduced by analyzing the output voltages of the detecting probes and the Rogowski probe. The feasibility of the method is verified by comparing the results with pictures from a high speed camera taken simultaneously.

Energy Efficiency of Induction Motors Running Off Frequency Converters with Pulse-Width Voltage Modulation{sup 1}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shvetsov, N. K., E-mail: elmash@em.ispu.ru

2016-11-15

The results of calculations of the increase in losses in an induction motor with frequency control and different forms of the supply voltage are presented. The calculations were performed by an analytic method based on harmonic analysis of the supply voltage as well as numerical calculation of the electromagnetic processes by the finite-element method.

Determining Detection and Classification Potential of Munitions using Advanced EMI Sensors in the Underwater Environment

DTIC Science & Technology

2016-11-01

focuses on characterizing Electromagnetic Induction (EMI) responses in the underwater setting through numerical and experimental studies with the...marine EMI sensing. 15. SUBJECT TERMS Munitions Response, Electromagnetic Induction, Unexploded Ordnance, Classification 16. SECURITY CLASSIFICATION...using Advanced EMI Sensors in the Underwater Environment.” The project focuses on characterizing Electromagnetic Induction (EMI) responses in the

Inductive System for Reliable Magnesium Level Detection in a Titanium Reduction Reactor

NASA Astrophysics Data System (ADS)

Krauter, Nico; Eckert, Sven; Gundrum, Thomas; Stefani, Frank; Wondrak, Thomas; Frick, Peter; Khalilov, Ruslan; Teimurazov, Andrei

2018-05-01

The determination of the Magnesium level in a Titanium reduction retort by inductive methods is often hampered by the formation of Titanium sponge rings which disturb the propagation of electromagnetic signals between excitation and receiver coils. We present a new method for the reliable identification of the Magnesium level which explicitly takes into account the presence of sponge rings with unknown geometry and conductivity. The inverse problem is solved by a look-up-table method, based on the solution of the inductive forward problems for several tens of thousands parameter combinations.

Induction heating apparatus and methods of operation thereof

DOEpatents

Richardson, John G.

2006-08-01

Methods of operation of an induction melter include providing material within a cooled crucible proximate an inductor. A desired electromagnetic flux skin depth for heating the material within the crucible may be selected, and a frequency of an alternating current for energizing the inductor and for producing the desired skin depth may be selected. The alternating current frequency may be adjusted after energizing the inductor to maintain the desired electromagnetic flux skin depth. The desired skin depth may be substantially maintained as the temperature of the material varies. An induction heating apparatus includes a sensor configured to detect changes in at least one physical characteristic of a material to be heated in a crucible, and a controller configured for selectively varying a frequency of an alternating current for energizing an inductor at least partially in response to changes in the physical characteristic to be detected by the sensor.

ESTCP Munitions Response Live Site Demonstrations, Former Southwestern Proving Ground, Arkansas Demonstration Report

DTIC Science & Technology

2015-07-01

electromagnetic induction (EMI) sensor. A total of 2,116 targets were selected from the dynamic data for cued investigation, and 1,398 targets were...geophysical mapping DSB Defense Science Board EE/CA Engineering Evaluation/Cost Analysis EMI electromagnetic induction ESTCP Environmental Security...performed a live site demonstration project using the Geometrics MetalMapper advanced electromagnetic induction (EMI) sensor at the former Southwestern

Infrared signal generation from AC induction field heating of graphite foam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klett, James W.; Rios, Orlando

A magneto-energy apparatus includes an electromagnetic field source for generating a time-varying electromagnetic field. A graphite foam conductor is disposed within the electromagnetic field. The graphite foam when exposed to the time-varying electromagnetic field conducts an induced electric current, the electric current heating the graphite foam to produce light. An energy conversion device utilizes light energy from the heated graphite foam to perform a light energy consuming function. A device for producing light and a method of converting energy are also disclosed.

Generation of electromagnetic energy in a magnetic cumulation generator with the use of inductively coupled circuits with a variable coupling coefficient

NASA Astrophysics Data System (ADS)

Gilev, S. D.; Prokopiev, V. S.

2017-07-01

A method of generation of electromagnetic energy and magnetic flux in a magnetic cumulation generator is proposed. The method is based on dynamic variation of the circuit coupling coefficient. This circuit is compared with other available circuits of magnetic energy generation with the help of magnetic cumulation (classical magnetic cumulation generator, generator with transformer coupling, and generator with a dynamic transformer). It is demonstrated that the proposed method allows obtaining high values of magnetic energy. The proposed circuit is found to be more effective than the known transformer circuit. Experiments on electromagnetic energy generation are performed, which demonstrate the efficiency of the proposed method.

Quality Control Methodologies for Advanced EMI Sensor Data Acquisition and Anomaly Classification - Former Southwestern Proving Ground, Arkansas

DTIC Science & Technology

2015-07-01

concentrations. A total of 11.23 acres of dynamic surveys were conducted using MetalMapper advanced electromagnetic induction (EMI) sensor. A total of...centimeter DGM digital geophysical mapping DSB Defense Science Board EE/CA Engineering Evaluation/Cost Analysis EMI electromagnetic induction...performed a live site demonstration project using the Geometrics MetalMapper advanced electromagnetic induction (EMI) sensor at the former

Portable Electromagnetic Induction Sensor with Integrated Positioning

DTIC Science & Technology

2013-08-20

Subsurface electromagnetic induction imaging for unexploded ordnance detection. Journal of Applied Geophysics, 79:38 – 45, 2012. ISSN 09269851. URL http...Portable Electromagnetic Induction Sensor with Integrated Positioning MR-1712 Final Report Submitted to Strategic Environmental Research and...19a. NAME OF RESPONSIBLE PERSON 19b. TELEPHONE NUMBER (include area code) Standard Form 298 (Rev. 8–98) Prescribed by ANSI Std. Z39.18 06–25–2013

University Students' Understanding of Electromagnetic Induction

ERIC Educational Resources Information Center

Guisasola, Jenaro; Almudi, Jose M.; Zuza, Kristina

2013-01-01

This study examined engineering and physical science students' understanding of the electromagnetic induction (EMI) phenomena. It is assumed that significant knowledge of the EMI theory is a basic prerequisite when students have to think about electromagnetic phenomena. To analyse students' conceptions, we have taken into account the fact that…

Status and Prospects for Developing Electromagnetic Methods and Facilities for Engineer Reconnaissance in Russia

NASA Astrophysics Data System (ADS)

Potekaev, A. I.; Donchenko, V. A.; Zambalov, S. D.; Parvatov, G. N.; Smirnov, I. M.; Svetlichnyi, V. A.; Yakubov, V. P.; Yakovlev, I. A.

2018-03-01

An analysis of the most effective methods, techniques and scientific-research developments of induction mine detectors is performed, their comparative tactical-technical characteristics are reported, and priority avenues for further research are outlined.

Superconducting-electromagnetic hybrid bearing using YBCO bulk blocks for passive axial levitation

NASA Astrophysics Data System (ADS)

Nicolsky, R.; de Andrade, R., Jr.; Ripper, A.; David, D. F. B.; Santisteban, J. A.; Stephan, R. M.; Gawalek, W.; Habisreuther, T.; Strasser, T.

2000-06-01

A superconducting/electromagnetic hybrid bearing has been designed using active radial electromagnetic positioning and a superconducting passive axial levitator. This bearing has been tested for an induction machine with a vertical shaft. The prototype was conceived as a four-pole, two-phase induction machine using specially designed stator windings for delivering torque and radial positioning simultaneously. The radial bearing uses four eddy-current sensors, displaced 90° from each other, for measuring the shaft position and a PID control system for feeding back the currents. The stator windings have been adapted from the ones of a standard induction motor. The superconducting axial bearing has been assembled with commercial NdFeB permanent magnets and a set of seven top-seeded-melt-textured YBCO large-grain cylindrical blocks. The bearing set-up was previously simulated by a finite element method for different permanent magnet-superconductor block configurations. The stiffness of the superconducting axial bearing has been investigated by measuring by a dynamic method the vertical and transversal elastic constants for different field cooling processes. The resulting elastic constants show a linear dependence on the air gap, i.e. the clearance between the permanent magnet assembly and the set of superconducting large-grain blocks, which is dependent on cooling distance.

Impact of Electromagnetic Field upon Temperature Measurement of Induction Heated Charges

NASA Astrophysics Data System (ADS)

Smalcerz, A.; Przylucki, R.

2013-04-01

The use of thermoelements is a commonly applied method in industry and engineering. It provides a wide measurement range of temperature, a direct voltage signal from the transducer, low cost of the thermoelement, and its resistance to many unfavorable factors which occur in an industrial environment. Unfortunately, thermoelements may not be resistant to interferences of a strong electromagnetic field because of the nature and design of a transducer. Induction heating is the most commonly used type of heating, at present, for metals. In order to guarantee the correctness of the carried out heating process, it is essential to control the temperature of the heated element. The impact of a strong electromagnetic field upon the thermocouple temperature measurement of the inductively heated elements has been analyzed in this paper. The experiment includes dozens of measurements where the following parameters have been varied: frequency of the current which feeds the heating inductor, power supplied to the heating system, geometry of heat inductor, and the charge material and its geometrical dimensions. Interferences of the power-line frequency have been eliminated in part of the carried out measurements.

Investigating Electromagnetic Induction through a Microcomputer-Based Laboratory.

ERIC Educational Resources Information Center

Trumper, Ricardo; Gelbman, Moshe

2000-01-01

Describes a microcomputer-based laboratory experiment designed for high school students that very accurately analyzes Faraday's law of electromagnetic induction, addressing each variable separately while the others are kept constant. (Author/CCM)

Analysis of Power Supply Heating Effect during High Temperature Experiments Based on the Electromagnetic Steel Teeming Technology

NASA Astrophysics Data System (ADS)

He, Ming; Wang, Qiang; Liu, Xin'an; Shi, Chunyang; Liu, Tie; He, Jicheng

2017-04-01

For further lowering inclusions and improving the quality of steel, a new electromagnetic steel-teeming technology based on electromagnetic induction heating was proposed. To assess the proposed technology, an experimental platform that imitates the actual production condition of steelmakers was established. High temperature experiments were performed to investigate the melting length of Fe-C alloy under different power and frequency conditions. The heating effect was analyzed, and the method of magnetic shielding to reduce the power loss of power supply was put forward. The results show that when the power is 40 kW and frequency is 25 kHz, the melting length of the Fe-C alloy is 89.2 mm in 120 s, which meets the requirements of steel teeming. In addition, when magnetic shielding material is installed under the induction coil, the power loss is reduced by about 64 %, effectively improving the heating effect of power supply.

Fuel saver based on electromagnetic induction for automotive engine

NASA Astrophysics Data System (ADS)

Siregar, Houtman P.; Sibarani, Maradu

2007-12-01

In the considered research is designed and analyzed the performance of the fuel saver which is based on electromagnetic induction for automotive diesel engine. The fuel saver which is based on permanent magnet has sold in market and its performance has tested. In comparison to the former fuel saver, in the proposed work is produced fuel saver which is based on electromagnetic induction. The considered research is the continuation of my former work. Performance of the produced fuel saver which is installed in the fuel line of internal combustion engine rig is compared to the performance of the standard internal combustion engine rig Speed of the engine, wire diameter of coil, and number of coil which is coiled in the winding of the the fuel saver are chosen as the testing variables. The considered research has succeeded to design the fuel saver which is based on electromagnetic induction for saving the automotive fuel consumption. Results of the research show that the addition of the fuel saver which is based on electromagnetic induction to the flow of the diesel fuel can significantly save the automative fuel consumption. In addition the designed fuel saver can reduce the opacity of the emission gas.

Analytical estimation on divergence and flutter vibrations of symmetrical three-phase induction stator via field-synchronous coordinates

NASA Astrophysics Data System (ADS)

Xia, Ying; Wang, Shiyu; Sun, Wenjia; Xiu, Jie

2017-01-01

The electromagnetically induced parametric vibration of the symmetrical three-phase induction stator is examined. While it can be analyzed by an approximate analytical or numerical method, more accurate and simple analytical method is desirable. This work proposes a new method based on the field-synchronous coordinates. A mechanical-electromagnetic coupling model is developed under this frame such that a time-invariant governing equation with gyroscopic term can be developed. With the general vibration theory, the eigenvalue is formulated; the transition curves between the stable and unstable regions, and response are all determined as closed-form expressions of basic mechanical-electromagnetic parameters. The dependence of these parameters on the instability behaviors is demonstrated. The results imply that the divergence and flutter instabilities can occur even for symmetrical motors with balanced, constant amplitude and sinusoidal voltage. To verify the analytical predictions, this work also builds up a time-variant model of the same system under the conventional inertial frame. The Floquét theory is employed to predict the parametric instability and the numerical integration is used to obtain the parametric response. The parametric instability and response are both well compared against those under the field-synchronous coordinates. The proposed field-synchronous coordinates allows a quick estimation on the electromagnetically induced vibration. The convenience offered by the body-fixed coordinates is discussed across various fields.

A Simulation Study on Optimal Design Parameters of 200V Class Induction Range using Finite Element Method

NASA Astrophysics Data System (ADS)

Ohchi, Masashi; Furukawa, Tatsuya

Induction heating has found a new feasibility in domestic appliances. Its application is known as an “induction range” or an “induction heating oven”. Conventional design schemes of them have depended on the experience and insight of designers. In the paper, the authors treat it as an electromagnetic device to investigate the mechanism of power dissipation using the Finite Element Method, where an impressed voltage supply is taken account of and the constant V/f condition is imposed for the constant impressed magnetic flux. Furthermore the authors will examine how to heat an aluminum pan and discuss the optimal frequency of a power supply.

Approximate analytical solution for induction heating of solid cylinders

DOE PAGES

Jankowski, Todd Andrew; Pawley, Norma Helen; Gonzales, Lindsey Michal; ...

2015-10-20

An approximate solution to the mathematical model for induction heating of a solid cylinder in a cylindrical induction coil is presented here. The coupled multiphysics model includes equations describing the electromagnetic field in the heated object, a heat transfer simulation to determine temperature of the heated object, and an AC circuit simulation of the induction heating power supply. A multiple-scale perturbation method is used to solve the multiphysics model. The approximate analytical solution yields simple closed-form expressions for the electromagnetic field and heat generation rate in the solid cylinder, for the equivalent impedance of the associated tank circuit, and formore » the frequency response of a variable frequency power supply driving the tank circuit. The solution developed here is validated by comparing predicted power supply frequency to both experimental measurements and calculated values from finite element analysis for heating of graphite cylinders in an induction furnace. The simple expressions from the analytical solution clearly show the functional dependence of the power supply frequency on the material properties of the load and the geometrical characteristics of the furnace installation. In conclusion, the expressions developed here provide physical insight into observations made during load signature analysis of induction heating.« less

Inductive Interference in Rapid Transit Signaling Systems. Volume 3. Data and Test Results.

DOT National Transportation Integrated Search

1986-11-01

This report presents comparative inductive interference data obtained from four U.S. rapid transit systems employing chopper propulsion control, as part of the Rail Transit Electromagnetic Interference/Electromagnetic Compatibility program conducted ...

Analysis of the mechanical stresses on a squirrel cage induction motor by the finite element method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jun, C.H.; Nicolas, A.

1999-05-01

The mechanical deformations and stresses have been analyzed by the Finite Element Method (FEM) in 3 dimensions on the rotor bars of a small squirrel cage induction motor. The authors considered the magnetic forces and the centrifugal forces as sources which provoked the deformations and stresses on the rotor bars. The mechanical calculations have been performed after doing the electromagnetic Finite Element modeling on the motor in steady states with various slip conditions.

Evaluation of Discrimination Technologies and Classification Results Live Site Demonstration: Former Waikoloa Maneuver Area

DTIC Science & Technology

2015-06-01

National Instruments. The National Instruments DAQ is a full-featured PC running Windows 7. The DAQ, electromagnetic transmitter , and batteries for the... electromagnetic induction Environet Environet, Inc. ESTCP Environmental Security Technology Certification Program ftp file transfer protocol FUDS formerly used...capabilities of a currently available advanced electromagnetic induction sensor developed specifically for discrimination on real sites under operational

The measurement of heats of solution of high melting metallic systems in an electromagnetic levitation field. Ph.D. Thesis - Tech. Univ. Berlin - 1979

NASA Technical Reports Server (NTRS)

Frohberg, M. G.; Betz, G.

1982-01-01

A method was tested for measuring the enthalpies of mixing of liquid metallic alloying systems, involving the combination of two samples in the electromagnetic field of an induction coil. The heat of solution is calculated from the pyrometrically measured temperature effect, the heat capacity of the alloy, and the heat content of the added sample. The usefulness of the method was tested experimentally with iron-copper and niobium-silicon systems. This method should be especially applicable to high-melting alloys, for which conventional measurements have failed.

Coupling and power transfer efficiency enhancement of modular and array of planar coils using in-plane ring-shaped inner ferrites for inductive heating applications

NASA Astrophysics Data System (ADS)

Kilic, V. T.; Unal, E.; Demir, H. V.

2017-07-01

We propose and demonstrate a highly effective method of enhancing coupling and power transfer efficiency in inductive heating systems composed of planar coils. The proposed method is based on locating ring-shaped ferrites in the inner side of the coils in the same plane. Measurement results of simple inductive heating systems constructed with either a single or a pair of conventional circular coils show that, with the in-plane inner ferrites, the total dissipated power of the system is increased by over 65%. Also, with three-dimensional full electromagnetic solutions, it is found that power transfer efficiency of the system is increased up to 92% with the inner ferrite placement. The proposed method is promising to be used for efficiency enhancement in inductive heating applications, especially in all-surface induction hobs.

Development of a low noise induction magnetic sensor using magnetic flux negative feedback in the time domain.

PubMed

Wang, X G; Shang, X L; Lin, J

2016-05-01

Time-domain electromagnetic system can implement great depth detection. As for the electromagnetic system, the receiver utilized an air coil sensor, and the matching mode of the sensor employed the resistance matching method. By using the resistance matching method, the vibration of the coil in the time domain can be effectively controlled. However, the noise of the sensor, especially the noise at the resonance frequency, will be increased as well. In this paper, a novel design of a low noise induction coil sensor is proposed, and the experimental data and noise characteristics are provided. The sensor is designed based on the principle that the amplified voltage will be converted to current under the influence of the feedback resistance of the coil. The feedback loop around the induction coil exerts a magnetic field and sends the negative feedback signal to the sensor. The paper analyses the influence of the closed magnetic feedback loop on both the bandwidth and the noise of the sensor. The signal-to-noise ratio is improved dramatically.

Localized mold heating with the aid of selective induction for injection molding of high aspect ratio micro-features

NASA Astrophysics Data System (ADS)

Park, Keun; Lee, Sang-Ik

2010-03-01

High-frequency induction is an efficient, non-contact means of heating the surface of an injection mold through electromagnetic induction. Because the procedure allows for the rapid heating and cooling of mold surfaces, it has been recently applied to the injection molding of thin-walled parts or micro/nano-structures. The present study proposes a localized heating method involving the selective use of mold materials to enhance the heating efficiency of high-frequency induction heating. For localized induction heating, a composite injection mold of ferromagnetic material and paramagnetic material is used. The feasibility of the proposed heating method is investigated through numerical analyses in terms of its heating efficiency for localized mold surfaces and in terms of the structural safety of the composite mold. The moldability of high aspect ratio micro-features is then experimentally compared under a variety of induction heating conditions.

Control of electromagnetic stirring by power focusing in large induction crucible furnaces

NASA Astrophysics Data System (ADS)

Frizen, V. E.; Sarapulov, F. N.

2011-12-01

An approach is proposed for the calculation of the operating conditions of an induction crucible furnace at the final stage of melting with the power focused in various regions of melted metal. The calculation is performed using a model based on the method of detailed magnetic equivalent circuits. The combination of the furnace and a thyristor frequency converter is taken into account in modeling.

Nutrient Estimation Using Subsurface Sensing Methods

USDA-ARS?s Scientific Manuscript database

This report investigates the use of precision management techniques for measuring soil conductivity on feedlot surfaces to estimate nutrient value for crop production. An electromagnetic induction soil conductivity meter was used to collect apparent soil electrical conductivity (ECa) from feedlot p...

A Double Layer Model of the Electromagnetic and Thermal Processes in Induction Heating of Ferromagnetic Material

NASA Astrophysics Data System (ADS)

Gilev, B.; Kraev, G.; Venkov, G. I.

2007-10-01

This paper presents the modeling of electromagnetic and heating processes in an inductor, where cylindrical ferromagnetic material has been placed. In the first part the electromagnetic mathematical problem is solved, as a result the power density is obtained. The power density takes part in the heat conduction equation. In the second part the thermal mathematical problem is solved, as a result the alteration of the temperature of the ferromagnetic material during the heating process is obtained. The parameters in both mathematical problems depend on the temperature. Because of that the stitching method is used for their finding. In [3, 4] the same mathematical problems are solved by the finite elements method. Comparing our results to those from [3] shows that they are similar. In contrast to [3, 4] our method allows the continuation of the analysis with the finding of the load power during the heating process. Thus result permits the determination of the load power alteration in the supplying inverter [1]. It is well-known that during the induction hardening it is necessary to maintain constant current amplitude in the load circuit of the inverter. So the next aim of this research is to build up a controller, based on the developed model, which will procure the necessary mode.

Perform MetalMapper Classification Treatability Investigations as Part of Remedial Investigation/Feasibility Studies: Live Site Demonstrations: Pueblo Chemical Depot

DTIC Science & Technology

2016-03-14

DoD Department of Defense EMI electromagnetic induction ESTCP Environmental Security Technology Certification Program ft. foot GPS global...three primary objectives:  Test and validate detection and discrimination capabilities of a currently available advanced electromagnetic induction ... induction (EMI) sensors in dynamic and static data acquisition modes and associated analysis software. To achieve these objectives, a controlled test was

The Teaching of Electromagnetic Induction at Sixth Form Level

ERIC Educational Resources Information Center

Archenhold, W. F.

1974-01-01

Presents some ideas about teaching electromagnetic induction at sixth form level, including educational objectives, learning difficulties, syllabus requirements, selection of unit system, and sequence of material presentation. Suggests the Education Group of the Institute of Physics hold further discussions on these aspects before including the…

Chapter 9.5: Electromagnetic induction to manage cattle feedlot waste

USDA-ARS?s Scientific Manuscript database

This book chapter summarizes results of waste management research that utilized electromagnetic induction (EMI) tools for the purposes of: 1) collection of solid waste from feedlot surfaces to be utilized by crops 2) control and utilization of nutrient laden liquid runoff, and 3) feedlot surface man...

Study on magnetic force of electromagnetic levitation circular knitting machine

NASA Astrophysics Data System (ADS)

Wu, X. G.; Zhang, C.; Xu, X. S.; Zhang, J. G.; Yan, N.; Zhang, G. Z.

2018-06-01

The structure of the driving coil and the electromagnetic force of the test prototype of electromagnetic-levitation (EL) circular knitting machine are studied. In this paper, the driving coil’s structure and working principle of the EL circular knitting machine are firstly introduced, then the mathematical modelling analysis of the driving electromagnetic force is carried out, and through the Ansoft Maxwell finite element simulation software the coil’s magnetic induction intensity and the needle’s electromagnetic force is simulated, finally an experimental platform is built to measure the coil’s magnetic induction intensity and the needle’s electromagnetic force. The results show that the theoretical analysis, the simulation analysis and the results of the test are very close, which proves the correctness of the proposed model.

Application of Advanced Concepts and Techniques in Electromagnetic Topology Based Simulations: CRIPTE and Related Codes

DTIC Science & Technology

2008-12-01

multiconductor transmission line theory. The per-unit capacitance, inductance , and characteristic impedance matrices generated from the companion LAPLACE...code based on the Method of Moments application, by meshing different sections of the multiconductor cable for capacitance and inductance matrices [21...conductors held together in four pairs and resided in the cable jacket. Each of eight conductors was also designed with the per unit length resistance

Electromagnetic induction and radiation-induced abnormality of wave propagation in excitable media

NASA Astrophysics Data System (ADS)

Ma, Jun; Wu, Fuqiang; Hayat, Tasawar; Zhou, Ping; Tang, Jun

2017-11-01

Continuous wave emitting from sinus node of the heart plays an important role in wave propagating among cardiac tissue, while the heart beating can be terminated when the target wave is broken into turbulent states by electromagnetic radiation. In this investigation, local periodical forcing is applied on the media to induce continuous target wave in the improved cardiac model, which the effect of electromagnetic induction is considered by using magnetic flux, then external electromagnetic radiation is imposed on the media. It is found that target wave propagation can be blocked to stand in a local area and the excitability of media is suppressed to approach quiescent but homogeneous state when electromagnetic radiation is imposed on the media. The sampled time series for membrane potentials decrease to quiescent state due to the electromagnetic radiation. It could accounts for the mechanism of abnormality in heart failure exposed to continuous electromagnetic field.

Electromagnetic Propulsion

NASA Technical Reports Server (NTRS)

Schafer, Charles

2000-01-01

The design and development of an Electromagnetic Propulsion is discussed. Specific Electromagnetic Propulsion Topics discussed include: (1) Technology for Pulse Inductive Thruster (PIT), to design, develop, and test of a multirepetition rate pulsed inductive thruster, Solid-State Switch Technology, and Pulse Driver Network and Architecture; (2) Flight Weight Magnet Survey, to determine/develop light weight high performance magnetic materials for potential application Advanced Space Flight Systems as these systems develop; and (3) Magnetic Flux Compression, to enable rapid/robust/reliable omni-planetary space transportation within realistic development and operational costs constraints.

Effects of Gender and Collaborative Learning Approach on Students' Conceptual Understanding of Electromagnetic Induction

ERIC Educational Resources Information Center

Adolphus, Telima; Omeodu, Doris

2016-01-01

The study investigates the effect of gender and collaborative learning approach on students' conceptual understanding of electromagnetic induction in Secondary Schools in Nigeria. Three research questions and 2 hypotheses were formulated to guide the research. The research design adopted for this study is the quasi-experimental design. In…

Addressing Students' Difficulties with Faraday's Law: A Guided Problem Solving Approach

ERIC Educational Resources Information Center

Zuza, Kristina; Almudí, José-Manuel; Leniz, Ane; Guisasola, Jenaro

2014-01-01

In traditional teaching, the fundamental concepts of electromagnetic induction are usually quickly analyzed, spending most of the time solving problems in a more or less rote manner. However, physics education research has shown that the fundamental concepts of the electromagnetic induction theory are barely understood by students. This article…

Introduction to the special section ‘Applications of electromagnetic induction to digital soil mapping’

USDA-ARS?s Scientific Manuscript database

Use of electromagnetic induction (EMI) instruments has increased as a tool to map soils because it provides a means of locating suitable sampling sites that provide the basis for mapping the spatial variability of various soil properties either directly or indirectly measured with EMI, including sa...

Electricity and Magnetism

NASA Astrophysics Data System (ADS)

Glazebrook, R. T.

2016-10-01

1. Electrostatics: fundamental facts; 2. Electricity as a measurable quantity; 3. Measurement of electric force and potential; 4. Condensers; 5. Electrical machines; 6. Measurement of potential and electric force; 7. Magnetic attraction and repulsion; 8. Laws of magnetic force; 9. Experiments with magnets; 10. Magnetic calculations; 11. Magnetic measurements; 12. Terrestrial magnetism; 13. The electric current; 14. Relation between electromagnetic force and current; 15. Measurement of current; 16. Measurement of resistance and electromotive force; 17. Measurement of quantity of electricity, condensers; 18. Thermal activity of a current; 19. The voltaic cell (theory); 20. Electromagnetism; 21. Magnetisation of iron; 22. Electromagnetic instruments; 23. Electromagnetic induction; 24. Applications of electromagnetic induction; 25. Telegraphy and telephony; 26. Electric waves; 27. Transference of electricity through gases: corpuscles and electrons; Answers to examples; Index.

Snow Depth Calibrations for Electromagnetic Induction Investigations at a Former Munitions Waste Disposal Site in Alaska

NASA Astrophysics Data System (ADS)

Glaser, D. R., II; Wagner, A. M.; Gelvin, A.; Saari, S.; Staples, A.; Larsen, G.

2017-12-01

A US Army legacy munitions waste site was identified adjacent to a river near a small arms range in Alaska. As part of remediation efforts, geophysical studies were conducted to characterize the extent of buried metal debris at the site. Time-domain electromagnetic surveys were completed over the site to meet the regulatory guidance for site cleanup. Time-domain and frequency-domain electromagnetic induction, magnetic gradiometry, and ground penetrating radar subsurface geophysical studies were deployed over soil, water, and snow surface conditions throughout the impacted area. The time-domain electromagnetic induction results acquired during summer months, presented clear indications of trenches located directly perpendicular to and adjacent to the river. However, in the follow up investigation where the snow-pack was greater than one meter, the response amplitude of the metallic debris was dampened and possible targets were missed. This was confirmed by the subsequent magnetic gradiometry survey which identified a suspected extension of one of the trenches through the river on to the seasonal sand bar island. The region is subject to extremely cold temperatures as well as significant snow pack and permafrost soil conditions. The snow presented a negative impact to the accurate assessment of the site by changing the effective investigation depth. To address this we developed an approach using ground penetrating radar data calibrated with physical snow depth measurements to generate continuous estimates of snow depth and spatially correct the electromagnetic induction data to the corresponding regulatory amplitude limit as if the snow were not present. Limitations of the approach as related to the signal floor of the electromagnetic induction response were also assessed.

Inductive dielectric analyzer

NASA Astrophysics Data System (ADS)

Agranovich, Daniel; Polygalov, Eugene; Popov, Ivan; Ben Ishai, Paul; Feldman, Yuri

2017-03-01

One of the approaches to bypass the problem of electrode polarization in dielectric measurements is the free electrode method. The advantage of this technique is that, the probing electric field in the material is not supplied by contact electrodes, but rather by electromagnetic induction. We have designed an inductive dielectric analyzer based on a sensor comprising two concentric toroidal coils. In this work, we present an analytic derivation of the relationship between the impedance measured by the sensor and the complex dielectric permittivity of the sample. The obtained relationship was successfully employed to measure the dielectric permittivity and conductivity of various alcohols and aqueous salt solutions.

On the relevance of source effects in geomagnetic pulsations for induction soundings

NASA Astrophysics Data System (ADS)

Neska, Anne; Tadeusz Reda, Jan; Leszek Neska, Mariusz; Petrovich Sumaruk, Yuri

2018-03-01

This study is an attempt to close a gap between recent research on geomagnetic pulsations and their usage as source signals in electromagnetic induction soundings (i.e., magnetotellurics, geomagnetic depth sounding, and magnetovariational sounding). The plane-wave assumption as a precondition for the proper performance of these methods is partly violated by the local nature of field line resonances which cause a considerable portion of pulsations at mid latitudes. It is demonstrated that and explained why in spite of this, the application of remote reference stations in quasi-global distances for the suppression of local correlated-noise effects in induction arrows is possible in the geomagnetic pulsation range. The important role of upstream waves and of the magnetic equatorial region for such applications is emphasized. Furthermore, the principal difference between application of reference stations for local transfer functions (which result in sounding curves and induction arrows) and for inter-station transfer functions is considered. The preconditions for the latter are much stricter than for the former. Hence a failure to estimate an inter-station transfer function to be interpreted in terms of electromagnetic induction, e.g., because of field line resonances, does not necessarily prohibit use of the station pair for a remote reference estimation of the impedance tensor.

Magneto-therapy of human joint cartilage.

PubMed

Wierzcholski, Krzysztof; Miszczak, Andrzej

2017-01-01

The topic of the present paper concerns the human joint cartilage therapy performed by the magnetic induction field. There is proved the thesis that the applied magnetic field for concrete cartilage illness should depend on the proper relative and concrete values of applied magnetic induction, intensity as well the time of treatment duration. Additionally, very important are frequencies and amplitudes of magnetic field as well as magnetic permeability of the synovial fluid. The research methods used in this paper include: magnetic induction field produced by a new Polish and German magneto electronic devices for the therapy of human joint cartilage diseases, stationary and movable magnetic applicators, magnetic bandage, ferrofluid injections, author's experience gained in Germany research institutes and practical results after measurements and information from patients. The results of this paper concern concrete parameters of time dependent electro-magnetic field administration during the joint cartilage therapy duration and additionally concern the corollaries which are implied from reading values gained on the magnetic induction devices. The main conclusions obtained in this paper are as follows: Time dependent magnetic induction field increases the dynamic viscosity of movable synovial fluid and decreases symptoms of cartilage illness for concrete intensity of magnetic field and concrete field line architecture. The ferrofluid therapy and phospholipids bilayer simultaneously with the administrated external electromagnetic field, increases the dynamic viscosity of movable synovial fluid.

A seafloor electromagnetic receiver for marine magnetotellurics and marine controlled-source electromagnetic sounding

NASA Astrophysics Data System (ADS)

Chen, Kai; Wei, Wen-Bo; Deng, Ming; Wu, Zhong-Liang; Yu, Gang

2015-09-01

In planning and executing marine controlled-source electromagnetic methods, seafloor electromagnetic receivers must overcome the problems of noise, clock drift, and power consumption. To design a receiver that performs well and overcomes the abovementioned problems, we performed forward modeling of the E-field abnormal response and established the receiver's characteristics. We describe the design optimization and the properties of each component, that is, low-noise induction coil sensor, low-noise Ag/AgCl electrode, low-noise chopper amplifier, digital temperature-compensated crystal oscillator module, acoustic telemetry modem, and burn wire system. Finally, we discuss the results of onshore and offshore field tests to show the effectiveness of the developed seafloor electromagnetic receiver and its performance: typical E-field noise of 0.12 nV/m/rt(Hz) at 0.5 Hz, dynamic range higher than 120 dB, clock drift lower than 1 ms/day, and continuous operation of at least 21 days.

Parameters assessment of the inductively-coupled circuit for wireless power transfer

NASA Astrophysics Data System (ADS)

Isaev, Yu N.; Vasileva, O. V.; Budko, A. A.; Lefebvre, S.

2017-02-01

In this paper, a wireless power transfer model through the example of inductively-coupled coils of irregular shape in software package COMSOL Multiphysics is studied. Circuit parameters, such as inductance, coil resistance and self-capacitance were defined through electromagnetic energy by the finite-element method. The study was carried out according to Helmholtz equation. Spatial distribution of current per unit depending on frequency and the coupling coefficient for analysis of resonant frequency and spatial distribution of the vector magnetic potential at different distances between coils were presented. The resulting algorithm allows simulating the wireless power transfer between the inductively coupled coils of irregular shape with the assessment of the optimal parameters.

Some Student Conceptions of Electromagnetic Induction

ERIC Educational Resources Information Center

Thong, Wai Meng; Gunstone, Richard

2008-01-01

Introductory electromagnetism is a central part of undergraduate physics. Although there has been some research into student conceptions of electromagnetism, studies have been sparse and separated. This study sought to explore second year physics students' conceptions of electromagnetism, to investigate to what extent the results from the present…

A Datalogger Demonstration of Electromagnetic Induction with a Falling, Oscillating and Swinging Magnet

ERIC Educational Resources Information Center

Wong, Darren; Lee, Paul; Foong, See Kit

2010-01-01

We investigate the electromagnetic induction phenomenon for a "falling," "oscillating" and "swinging" magnet and a coil, with the help of a datalogger. For each situation, we discuss the salient aspects of the phenomenon, with the aid of diagrams, and relate the motion of the magnet to its mathematical and graphical representations. Using various…

Using a PC and External Media to Quantitatively Investigate Electromagnetic Induction

ERIC Educational Resources Information Center

Bonanno, A.; Bozzo, G.; Camarca, M.; Sapia, P.

2011-01-01

In this article we describe an experimental learning path about electromagnetic induction which uses an Atwood machine where one of the two hanging bodies is a cylindrical magnet falling through a plexiglass guide, surrounded either by a coil or by a copper pipe. The first configuration (magnet falling across a coil) allows students to…

Improved methods for nightside time domain Lunar Electromagnetic Sounding

NASA Astrophysics Data System (ADS)

Fuqua-Haviland, H.; Poppe, A. R.; Fatemi, S.; Delory, G. T.; De Pater, I.

2017-12-01

Time Domain Electromagnetic (TDEM) Sounding isolates induced magnetic fields to remotely deduce material properties at depth. The first step of performing TDEM Sounding at the Moon is to fully characterize the dynamic plasma environment, and isolate geophysically induced currents from concurrently present plasma currents. The transfer function method requires a two-point measurement: an upstream reference measuring the pristine solar wind, and one downstream near the Moon. This method was last performed during Apollo assuming the induced fields on the nightside of the Moon expand as in an undisturbed vacuum within the wake cavity [1]. Here we present an approach to isolating induction and performing TDEM with any two point magnetometer measurement at or near the surface of the Moon. Our models include a plasma induction model capturing the kinetic plasma environment within the wake cavity around a conducting Moon, and a geophysical forward model capturing induction in a vacuum. The combination of these two models enable the analysis of magnetometer data within the wake cavity. Plasma hybrid models use the upstream plasma conditions and interplanetary magnetic field (IMF) to capture the wake current systems formed around the Moon. The plasma kinetic equations are solved for ion particles with electrons as a charge-neutralizing fluid. These models accurately capture the large scale lunar wake dynamics for a variety of solar wind conditions: ion density, temperature, solar wind velocity, and IMF orientation [2]. Given the 3D orientation variability coupled with the large range of conditions seen within the lunar plasma environment, we characterize the environment one case at a time. The global electromagnetic induction response of the Moon in a vacuum has been solved numerically for a variety of electrical conductivity models using the finite-element method implemented within the COMSOL software. This model solves for the geophysically induced response in vacuum to any driving transient event for any specified 3D conductivity profile. Our models fit the analytic solutions to a Root-Mean-Square Error of better than 1%. Solutions are non-unique, however, serve to better understand and constrain the global interior composition and 3D structure of the Moon. [1] Dyal & Parkin (1971) JGR; [2] Fatemi et al. (2013) GRL.

AC losses in horizontally parallel HTS tapes for possible wireless power transfer applications

NASA Astrophysics Data System (ADS)

Shen, Boyang; Geng, Jianzhao; Zhang, Xiuchang; Fu, Lin; Li, Chao; Zhang, Heng; Dong, Qihuan; Ma, Jun; Gawith, James; Coombs, T. A.

2017-12-01

This paper presents the concept of using horizontally parallel HTS tapes with AC loss study, and the investigation on possible wireless power transfer (WPT) applications. An example of three parallel HTS tapes was proposed, whose AC loss study was carried out both from experiment using electrical method; and simulation using 2D H-formulation on the FEM platform of COMSOL Multiphysics. The electromagnetic induction around the three parallel tapes was monitored using COMSOL simulation. The electromagnetic induction and AC losses generated by a conventional three turn coil was simulated as well, and then compared to the case of three parallel tapes with the same AC transport current. The analysis demonstrates that HTS parallel tapes could be potentially used into wireless power transfer systems, which could have lower total AC losses than conventional HTS coils.

Apparatus for and method of operating a cylindrical pulsed induction mass launcher

DOEpatents

Cowan, M. Jr.; Duggin, B.W.; Widner, M.M.

1992-06-30

An electromagnetic cylindrical projectile mass launcher and a method of operation is provided which includes a cylindrical projectile having a conducting armature, a cylindrical barrel in which the armature is received, a plurality of electromagnetic drive coil stages, a plurality of pulse energy sources, and a pulsed power arrangement for generating magnetic pulses forming a pulsed magnetic wave along the length of the launcher barrel. The pulsed magnetic wave provides a propelling force on the projectile along the drive coil. The pulsed magnetic wave of the drive coil stages is advanced along the armature faster than the projectile to thereby generate an induced current wave in the armature. The pulsed generation of the magnetic wave minimizes electromagnetic heating of the projectile and provides for smooth acceleration of the projectile through the barrel of the launcher. 2 figs.

Apparatus for and method of operating a cylindrical pulsed induction mass launcher

DOEpatents

Cowan, Jr., Maynard; Duggin, Billy W.; Widner, Melvin M.

1992-01-01

An electromagnetic cylindrical projectile mass launcher and a method of operation is provided which includes a cylindrical projectile having a conducting armature, a cylindrical barrel in which the armature is received, a plurality of electromagnetic drive coil stages, a plurality of pulse energy sources, and a pulsed power arrangement for generating magnetic pulses forming a pulsed magnetic wave along the length of the launcher barrel. The pulsed magnetic wave provides a propelling force on the projectile along the drive coil. The pulsed magnetic wave of the drive coil stages is advanced along the armature faster than the projectile to thereby generate an induced current wave in the armature. The pulsed generation of the magnetic wave minimizes electromagnetic heating of the projectile and provides for smooth acceleration of the projectile through the barrel of the launcher.

Seasonal variation in apparent conductivity and soil salinity at two Narragansett Bay salt marshes

EPA Science Inventory

Measurement of the apparent conductivity of salt marsh sediments using electromagnetic induction (EMI) is a rapid alternative to traditional methods of salinity determination that can be used to map soil salinity across a marsh surface. Soil salinity measures can provide informat...

Mapping Pesticide Partition Coefficients By Electromagnetic Induction

USDA-ARS?s Scientific Manuscript database

A potential method for reducing pesticide leaching is to base application rates on the leaching potential of a specific chemical and soil combination. However, leaching is determined in part by the partitioning of the chemical between the soil and soil solution, which varies across a field. Standard...

Modelling natural electromagnetic interference in man-made conductors for space weather applications

NASA Astrophysics Data System (ADS)

Trichtchenko, Larisa

2016-04-01

Power transmission lines above the ground, cables and pipelines in the ground and under the sea, and in general all man-made long grounded conductors are exposed to the variations of the natural electromagnetic field. The resulting currents in the networks (commonly named geomagnetically induced currents, GIC), are produced by the conductive and/or inductive coupling and can compromise or even disrupt system operations and, in extreme cases, cause power blackouts, railway signalling mis-operation, or interfere with pipeline corrosion protection systems. To properly model the GIC in order to mitigate their impacts it is necessary to know the frequency dependence of the response of these systems to the geomagnetic variations which naturally span a wide frequency range. For that, the general equations of the electromagnetic induction in a multi-layered infinitely long cylinder (representing cable, power line wire, rail or pipeline) embedded in uniform media have been solved utilising methods widely used in geophysics. The derived electromagnetic fields and currents include the effects of the electromagnetic properties of each layer and of the different types of the surrounding media. This exact solution then has been used to examine the electromagnetic response of particular samples of long conducting structures to the external electromagnetic wave for a wide range of frequencies. Because the exact solution has a rather complicated structure, simple approximate analytical formulas have been proposed, analysed and compared with the results from the exact model. These approximate formulas show good coincidence in the frequency range spanning from geomagnetic storms (less than mHz) to pulsations (mHz to Hz) to atmospherics (kHz) and above, and can be recommended for use in space weather applications.

Induction conductivity and natural gamma logs collected in 15 wells at Camp Stanley Storage Activity, Bexar County, Texas

USGS Publications Warehouse

Stanton, Gregory P.

2005-01-01

The U.S. Geological Survey, in cooperation with the Camp Stanley Storage Activity conducted electromagnetic induction conductivity and natural gamma logging of 15 selected wells on the Camp Stanley Storage Activity, located in northern Bexar County, Texas, during March 28–30, 2005. In late 2004, a helicopter electromagnetic survey was flown of the Camp Stanley Storage Activity as part of a U.S. Geological Survey project to better define subsurface geologic units, the structure, and the catchment area of the Trinity aquifer. The electromagnetic induction conductivity and natural gamma log data in this report were collected to constrain the calculation of resistivity depth sections and to provide subsurface controls for interpretation of the helicopter electromagnetic data collected for the Camp Stanley Storage Activity. Logs were recorded digitally while moving the probe in an upward direction to maintain proper depth control. Logging speed was no greater than 30 feet per minute. During logging, a repeat section of at least 100 feet was recorded to check repeatability of log responses. Several of the wells logged were completed with polyvinyl chloride casing that can be penetrated by electromagnetic induction fields and allows conductivity measurement. However, some wells were constructed with steel centralizers and stainless steel screen that caused spikes on both conductivity and resulting resistivity log curves. These responses are easily recognizable and appear at regular intervals on several logs.

Science 101: What Causes Electromagnetic Induction?

ERIC Educational Resources Information Center

Robertson, Bill

2013-01-01

Electromagnetic induction is the technical name for the fact that, when a wire is moved near a magnet or a magnet is moved near a wire, an electric current flows in the wire. Although Bill Robertson honestly admits to not knowing why this happens, he does say that it is possible to get a deeper understanding of what's going on in terms of…

A physical model for low-frequency electromagnetic induction in the near field based on direct interaction between transmitter and receiver electrons

PubMed Central

Smith, Ray T.; Jjunju, Fred P. M.; Young, Iain S.; Taylor, Stephen

2016-01-01

A physical model of electromagnetic induction is developed which relates directly the forces between electrons in the transmitter and receiver windings of concentric coaxial finite coils in the near-field region. By applying the principle of superposition, the contributions from accelerating electrons in successive current loops are summed, allowing the peak-induced voltage in the receiver to be accurately predicted. Results show good agreement between theory and experiment for various receivers of different radii up to five times that of the transmitter. The limitations of the linear theory of electromagnetic induction are discussed in terms of the non-uniform current distribution caused by the skin effect. In particular, the explanation in terms of electromagnetic energy and Poynting’s theorem is contrasted with a more direct explanation based on variable filament induction across the conductor cross section. As the direct physical model developed herein deals only with forces between discrete current elements, it can be readily adapted to suit different coil geometries and is widely applicable in various fields of research such as near-field communications, antenna design, wireless power transfer, sensor applications and beyond. PMID:27493580

A physical model for low-frequency electromagnetic induction in the near field based on direct interaction between transmitter and receiver electrons.

PubMed

Smith, Ray T; Jjunju, Fred P M; Young, Iain S; Taylor, Stephen; Maher, Simon

2016-07-01

A physical model of electromagnetic induction is developed which relates directly the forces between electrons in the transmitter and receiver windings of concentric coaxial finite coils in the near-field region. By applying the principle of superposition, the contributions from accelerating electrons in successive current loops are summed, allowing the peak-induced voltage in the receiver to be accurately predicted. Results show good agreement between theory and experiment for various receivers of different radii up to five times that of the transmitter. The limitations of the linear theory of electromagnetic induction are discussed in terms of the non-uniform current distribution caused by the skin effect. In particular, the explanation in terms of electromagnetic energy and Poynting's theorem is contrasted with a more direct explanation based on variable filament induction across the conductor cross section. As the direct physical model developed herein deals only with forces between discrete current elements, it can be readily adapted to suit different coil geometries and is widely applicable in various fields of research such as near-field communications, antenna design, wireless power transfer, sensor applications and beyond.

A new electromagnetic NDI-technique based on the measurement of source-sample reaction forces

NASA Astrophysics Data System (ADS)

Fitzpatrick, G. L.; Skaugset, R. L.; Shih, W. C. L.

2001-04-01

Faraday's law of induction, Lenz's law, the Lorentz force law and Newton's third law, taken together, insure that sources (e.g., coil sources) of time-dependent electromagnetic fields, and nearby "nonmagnetic" electrical conductors (e.g., aluminum), always experience mutually repulsive (source-conductor) forces. This fact forms the basis for a new method for detecting cracks and corrosion in (aging) multi-layer airframes. The presence of cracks or corrosion (e.g., material thinning) in these structures is observed to reduce (second-harmonic) source-conductor reaction forces.

Utilizing electromagnetic radiation for hair growth: a critical review of phototrichogenesis.

PubMed

Kalia, Sunil; Lui, Harvey

2013-01-01

Hair loss has a high prevalence in the general population and can have significant medical and psychological sequelae. Pattern hair loss and alopecia areata represent the major reasons patients present to dermatologists in relation to hair loss. Because conventional treatment options are generally incompletely effective, novel methods for hair grown induction are being developed. The role of using electromagnetic radiation, including low-level laser therapy for the management of hair loss through phototrichogenesis, is reviewed in this article. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

Advancements in Transmitters and Sensors for Biological Tissue Imaging in Magnetic Induction Tomography

PubMed Central

Zakaria, Zulkarnay; Rahim, Ruzairi Abdul; Mansor, Muhammad Saiful Badri; Yaacob, Sazali; Ayub, Nor Muzakkir Nor; Muji, Siti Zarina Mohd.; Rahiman, Mohd Hafiz Fazalul; Aman, Syed Mustafa Kamal Syed

2012-01-01

Magnetic Induction Tomography (MIT), which is also known as Electromagnetic Tomography (EMT) or Mutual Inductance Tomography, is among the imaging modalities of interest to many researchers around the world. This noninvasive modality applies an electromagnetic field and is sensitive to all three passive electromagnetic properties of a material that are conductivity, permittivity and permeability. MIT is categorized under the passive imaging family with an electrodeless technique through the use of excitation coils to induce an electromagnetic field in the material, which is then measured at the receiving side by sensors. The aim of this review is to discuss the challenges of the MIT technique and summarize the recent advancements in the transmitters and sensors, with a focus on applications in biological tissue imaging. It is hoped that this review will provide some valuable information on the MIT for those who have interest in this modality. The need of this knowledge may speed up the process of adopted of MIT as a medical imaging technology. PMID:22969341

An electromagnetic induction method for underground target detection and characterization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bartel, L.C.; Cress, D.H.

1997-01-01

An improved capability for subsurface structure detection is needed to support military and nonproliferation requirements for inspection and for surveillance of activities of threatening nations. As part of the DOE/NN-20 program to apply geophysical methods to detect and characterize underground facilities, Sandia National Laboratories (SNL) initiated an electromagnetic induction (EMI) project to evaluate low frequency electromagnetic (EM) techniques for subsurface structure detection. Low frequency, in this case, extended from kilohertz to hundreds of kilohertz. An EMI survey procedure had already been developed for borehole imaging of coal seams and had successfully been applied in a surface mode to detect amore » drug smuggling tunnel. The SNL project has focused on building upon the success of that procedure and applying it to surface and low altitude airborne platforms. Part of SNL`s work has focused on improving that technology through improved hardware and data processing. The improved hardware development has been performed utilizing Laboratory Directed Research and Development (LDRD) funding. In addition, SNL`s effort focused on: (1) improvements in modeling of the basic geophysics of the illuminating electromagnetic field and its coupling to the underground target (partially funded using LDRD funds) and (2) development of techniques for phase-based and multi-frequency processing and spatial processing to support subsurface target detection and characterization. The products of this project are: (1) an evaluation of an improved EM gradiometer, (2) an improved gradiometer concept for possible future development, (3) an improved modeling capability, (4) demonstration of an EM wave migration method for target recognition, and a demonstration that the technology is capable of detecting targets to depths exceeding 25 meters.« less

Counterpulse railgun energy recovery circuit

DOEpatents

Honig, E.M.

1984-09-28

The invention presented relates to a high-power pulsing circuit and more particularly to a repetitive pulse inductive energy storage and transfer circuit for an electromagnetic launcher. In an electromagnetic launcher such as a railgun for propelling a projectile at high velocity, a counterpulse energy recovery circuit is employed to transfer stored inductive energy from a source inductor to the railgun inductance to propel the projectile down the railgun. Switching circuitry and an energy transfer capacitor are used to switch the energy back to the source inductor in readiness for a repetitive projectile propelling cycle.

Overpulse railgun energy recovery circuit

DOEpatents

Honig, E.M.

1984-09-28

The invention presented relates to a high-power pulsing circuit and more particularly to a repetitive pulse inductive energy storage and transfer circuit for an electromagnetic launcher. In an electromagnetic launcher such as a railgun for propelling a projectile at high velocity, an overpulse energy recovery circuit is employed to transfer stored inductive energy from a source inductor to the railgun inductance to propel the projectile down the railgun. Switching circuitry and an energy transfer capacitor are used to switch the energy back to the source inductor in readiness for a repetitive projectile propelling cycle.

Electromagnetic Induction Sensing of UneXploded Ordnance with Pedemis

DTIC Science & Technology

2012-10-22

Pasion , L. R., “A unified approach to uxo discrimination using the method of auxiliary sources,” tech. rep. (2006). [19] Barrowes, B. E., O’Neill, K...inversion and classification using advanced emi models,” (2010). SERDP-MR-1572. [27] Pasion , L., “Uxo discrimination using full coverage and cued

Geophysical Surveys for Locating Buried Utilities, Lake Pontchartrain Levees, New Orleans

DTIC Science & Technology

2014-06-01

4 Figure 3. GPR concepts...this study. Electromagnetic (EM) induction, magnetic, and ground penetrating radar ( GPR ) geophysical methods were evaluated to determine which...surveys GPR is a ground-based geophysical instrument that transmits high- frequency EM pulses into the subsurface. The GPR system consists of a

The detection of brain oedema with frequency-dependent phase shift electromagnetic induction.

PubMed

González, César A; Rubinsky, Boris

2006-06-01

The spectroscopic distribution of inductive phase shift in the brain as a function of the relative volume of oedema was evaluated with theoretical and experimental methods in the frequency range 1 to 8 MHz. The theoretical study employed a simple mathematical model of electromagnetic induction in tissue and brain tissue data available from the literature to calculate the phase shift as a function of oedema in the bulk of the brain. Experimental data were generated from bulk measurements of ex vivo homogenized pig brain tissue mixed with various volumes of physiological saline in a volume sample typical of the human brain. There is good agreement between the analytical and the experimental results. Detectable changes in phase shift begin from a frequency of about 3 MHz to 4 MHz in the tested compositions and volume. The phase shift increases with frequency and fluid content. The results suggest that measuring phase shift in the bulk of the brain has the potential for becoming a robust means for non-contact detection of oedema in the brain.

Introduction to the JEEG Agricultural Geophysics Special Issue

USGS Publications Warehouse

Allred, Barry J.; Smith, Bruce D.

2010-01-01

Near-surface geophysical methods have become increasingly important tools in applied agricultural practices and studies. The great advantage of geophysical methods is their potential rapidity, low cost, and spatial continuity when compared to more traditional methods of assessing agricultural land, such as sample collection and laboratory analysis. Agricultural geophysics investigations commonly focus on obtaining information within the soil profile, which generally does not extend much beyond 2 meters beneath the ground surface. Although the depth of interest oftentimes is rather shallow, the area covered by an agricultural geophysics survey can vary widely in scale, from experimental plots (10 s to 100 s of square meters), to farm fields (10 s to 100 s of hectares), up to the size of watersheds (10 s to 100 s of square kilometers). To date, three predominant methods—resistivity, electromagnetic induction (EMI), and ground-penetrating radar (GPR)—have been used to obtain surface-based geophysical measurements within agricultural settings. However, a recent conference on agricultural geophysics (Bouyoucos Conference on Agricultural Geophysics, September 8–10, 2009, Albuquerque, New Mexico; www.ag-geophysics.org) illustrated that other geophysical methods are being applied or developed. These include airborne electromagnetic induction, magnetometry, seismic, and self-potential methods. Agricultural geophysical studies are also being linked to ground water studies that utilize deeper penetrating geophysical methods than normally used.

Physics Almost Saved the President! Electromagnetic Induction and the Assassination of James Garfield: A Teaching Opportunity in Introductory Physics

ERIC Educational Resources Information Center

Overduin, James; Molloy, Dana; Selway, Jim

2014-01-01

Electromagnetic induction is probably one of the most challenging subjects for students in the introductory physics sequence, especially in algebra-based courses. Yet it is at the heart of many of the devices we rely on today. To help students grasp and retain the concept, we have put together a simple and dramatic classroom demonstration that…

Inductive shearing of drilling pipe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ludtka, Gerard M.; Wilgen, John; Kisner, Roger

Induction shearing may be used to cut a drillpipe at an undersea well. Electromagnetic rings may be built into a blow-out preventer (BOP) at the seafloor. The electromagnetic rings create a magnetic field through the drillpipe and may transfer sufficient energy to change the state of the metal drillpipe to shear the drillpipe. After shearing the drillpipe, the drillpipe may be sealed to prevent further leakage of well contents.

Response of Electrical Activity in an Improved Neuron Model under Electromagnetic Radiation and Noise

PubMed Central

Zhan, Feibiao; Liu, Shenquan

2017-01-01

Electrical activities are ubiquitous neuronal bioelectric phenomena, which have many different modes to encode the expression of biological information, and constitute the whole process of signal propagation between neurons. Therefore, we focus on the electrical activities of neurons, which is also causing widespread concern among neuroscientists. In this paper, we mainly investigate the electrical activities of the Morris-Lecar (M-L) model with electromagnetic radiation or Gaussian white noise, which can restore the authenticity of neurons in realistic neural network. First, we explore dynamical response of the whole system with electromagnetic induction (EMI) and Gaussian white noise. We find that there are slight differences in the discharge behaviors via comparing the response of original system with that of improved system, and electromagnetic induction can transform bursting or spiking state to quiescent state and vice versa. Furthermore, we research bursting transition mode and the corresponding periodic solution mechanism for the isolated neuron model with electromagnetic induction by using one-parameter and bi-parameters bifurcation analysis. Finally, we analyze the effects of Gaussian white noise on the original system and coupled system, which is conducive to understand the actual discharge properties of realistic neurons. PMID:29209192

Response of Electrical Activity in an Improved Neuron Model under Electromagnetic Radiation and Noise.

PubMed

Zhan, Feibiao; Liu, Shenquan

2017-01-01

Electrical activities are ubiquitous neuronal bioelectric phenomena, which have many different modes to encode the expression of biological information, and constitute the whole process of signal propagation between neurons. Therefore, we focus on the electrical activities of neurons, which is also causing widespread concern among neuroscientists. In this paper, we mainly investigate the electrical activities of the Morris-Lecar (M-L) model with electromagnetic radiation or Gaussian white noise, which can restore the authenticity of neurons in realistic neural network. First, we explore dynamical response of the whole system with electromagnetic induction (EMI) and Gaussian white noise. We find that there are slight differences in the discharge behaviors via comparing the response of original system with that of improved system, and electromagnetic induction can transform bursting or spiking state to quiescent state and vice versa. Furthermore, we research bursting transition mode and the corresponding periodic solution mechanism for the isolated neuron model with electromagnetic induction by using one-parameter and bi-parameters bifurcation analysis. Finally, we analyze the effects of Gaussian white noise on the original system and coupled system, which is conducive to understand the actual discharge properties of realistic neurons.

Integrating surface and borehole geophysics in ground water studies - an example using electromagnetic soundings in south Florida

USGS Publications Warehouse

Paillet, Frederick; Hite, Laura; Carlson, Matthew

1999-01-01

Time domain surface electromagnetic soundings, borehole induction logs, and other borehole logging techniques are used to construct a realistic model for the shallow subsurface hydraulic properties of unconsolidated sediments in south Florida. Induction logs are used to calibrate surface induction soundings in units of pore water salinity by correlating water sample specific electrical conductivity with the electrical conductivity of the formation over the sampled interval for a two‐layered aquifer model. Geophysical logs are also used to show that a constant conductivity layer model is appropriate for the south Florida study. Several physically independent log measurements are used to quantify the dependence of formation electrical conductivity on such parameters as salinity, permeability, and clay mineral fraction. The combined interpretation of electromagnetic soundings and induction logs was verified by logging three validation boreholes, confirming quantitative estimates of formation conductivity and thickness in the upper model layer, and qualitative estimates of conductivity in the lower model layer.

The turbulent recirculating flow field in a coreless induction furnace. A comparison of theoretical predictions with measurements

NASA Technical Reports Server (NTRS)

El-Kaddah, N.; Szekely, J.

1982-01-01

A mathematical representation for the electromagnetic force field and the fluid flow field in a coreless induction furnace is presented. The fluid flow field was represented by writing the axisymmetric turbulent Navier-Stokes equation, containing the electromagnetic body force term. The electromagnetic body force field was calculated by using a technique of mutual inductances. The kappa-epsilon model was employed for evaluating the turbulent viscosity and the resultant differential equations were solved numerically. Theoretically predicted velocity fields are in reasonably good agreement with the experimental measurements reported by Hunt and Moore; furthermore, the agreement regarding the turbulent intensities are essentially quantitative. These results indicate that the kappa-epsilon model provides a good engineering representation of the turbulent recirculating flows occurring in induction furnaces. At this stage it is not clear whether the discrepancies between measurements and the predictions, which were not very great in any case, are attributable either to the model or to the measurement techniques employed.

If Maxwell had worked between Ampère and Faraday: An historical fable with a pedagogical moral

NASA Astrophysics Data System (ADS)

Jammer, Max; Stachel, John

1980-01-01

If one drops the Faraday induction term from Maxwell's equations, they become exactly Galilei invariant. This suggests that if Maxwell had worked between Ampère and Faraday, he could have developed this Galilei-invariant electromagnetic theory so that Faraday's discovery would have confronted physicists with the dilemma: give up the Galileian relativity principle for electromagnetism (ether hypothesis), or modify it (special relativity). This suggests a new pedagogical approach to electromagnetic theory, in which the displacement current and the Galileian relativity principle are introduced before the induction term is discussed.

Response simulation and theoretical calibration of a dual-induction resistivity LWD tool

NASA Astrophysics Data System (ADS)

Xu, Wei; Ke, Shi-Zhen; Li, An-Zong; Chen, Peng; Zhu, Jun; Zhang, Wei

2014-03-01

In this paper, responses of a new dual-induction resistivity logging-while-drilling (LWD) tool in 3D inhomogeneous formation models are simulated by the vector finite element method (VFEM), the influences of the borehole, invaded zone, surrounding strata, and tool eccentricity are analyzed, and calibration loop parameters and calibration coefficients of the LWD tool are discussed. The results show that the tool has a greater depth of investigation than that of the existing electromagnetic propagation LWD tools and is more sensitive to azimuthal conductivity. Both deep and medium induction responses have linear relationships with the formation conductivity, considering optimal calibration loop parameters and calibration coefficients. Due to the different depths of investigation and resolution, deep induction and medium induction are affected differently by the formation model parameters, thereby having different correction factors. The simulation results can provide theoretical references for the research and interpretation of the dual-induction resistivity LWD tools.

Preliminary investigation of structural controls of ground-water movement in Pipe Spring National Monument, Arizona

USGS Publications Warehouse

Truini, Margot; Fleming, John B.; Pierce, Herb A.

2004-01-01

Pipe Spring National Monument, near the border of Arizona and Utah, includes several low-discharge springs that are the primary natural features of the monument. The National Park Service is concerned about the declines in spring discharge. Seismic-refraction and frequency-domain electromagnetic-induction methods were employed in an attempt to better understand the relation between spring discharge and geologic structure. The particular method used for the seismic-refraction surveys was unable to resolve structural features in the monument. Electromagnetic surveys delineated differences in apparent conductivity of the shallow subsurface deposits. The differences are attributable to differences in saturation, lithology, and structure of these deposits.

An analysis of how electromagnetic induction and Faraday's law are presented in general physics textbooks, focusing on learning difficulties

NASA Astrophysics Data System (ADS)

Guisasola, Jenaro; Zuza, Kristina; Almudi, José-Manuel

2013-07-01

Textbooks are a very important tool in the teaching-learning process and influence important aspects of the process. This paper presents an analysis of the chapter on electromagnetic induction and Faraday's law in 19 textbooks on general physics for first-year university courses for scientists and engineers. This analysis was based on criteria formulated from the theoretical framework of electromagnetic induction in classical physics and students' learning difficulties concerning these concepts. The aim of the work presented here is not to compare a textbook against the ideal book, but rather to try and find a series of explanations, examples, questions, etc that provide evidence on how the topic is presented in relation to the criteria above. It concludes that despite many aspects being covered properly, there are others that deserve greater attention.

Spin Pit Application of Image Derotated Holographic Interferometry.

DTIC Science & Technology

1980-09-01

temperatures resulting from induction heating of the test structuore through the interaction of the electromagnets and the magnetic ring. Subsequent...reference beam, and a Tektronix Model 7633 storage oscilloscope. When the laser is fired, a trigger signal from the laser power supply initiates the...rapid induction heating of the test structure due to the interaction of the electromagnets and the magnetic ring was evi(lent with the switch from dc to

Subsurface Electromagnetic Induction Imaging for Unexploded Ordnance Detection

DTIC Science & Technology

2012-01-01

Baum, 1999; Pasion and Oldenburg, 2001). The EMI- response problem has been solved analytically for spheroids (Ao et al., 2002; Barrowes et al., 2004...components. We also have made explicit the fact that the polarizabilities are always positive ( Pasion et al., 2008); we impose this constraint in the...Wiley-Blackwell, Chichester, UK. Pasion , L.R., Oldenburg, D.W., 2001. A discrimination algorithm for UXO using time- domain electromagnetic induction

EM61-MK2 Response of Three Munitions Surrogates

DTIC Science & Technology

2009-03-12

time-domain electromagnetic induction sensors, it produces a pulsed magnetic field (primary field) that induces a secondary field in metallic objects...selected and marked as potential metal targets. This initial list of anomalies is used as input to an analysis step that selects anomalies for digging...response of a metallic object to an Electromagnetic Induction sensor is most simply modeled as an induced dipole moment represented by a magnetic

Promoting Conceptual Development in Physics Teacher Education: Cognitive-Historical Reconstruction of Electromagnetic Induction Law

ERIC Educational Resources Information Center

Mantyla, Terhi

2013-01-01

In teaching physics, the history of physics offers fruitful starting points for designing instruction. I introduce here an approach that uses historical cognitive processes to enhance the conceptual development of pre-service physics teachers' knowledge. It applies a method called cognitive-historical approach, introduced to the cognitive sciences…

Contiguous metallic rings: an inductive mesh with high transmissivity, strong electromagnetic shielding, and uniformly distributed stray light.

PubMed

Tan, Jiubin; Lu, Zhengang

2007-02-05

This paper presents the experimental study on an inductive mesh composed of contiguous metallic rings fabricated using UV-lithography on quartz glass. Experimental results indicate that, at the same period and linewidth as square mesh, ring mesh has better transmissivity for its higher obscuration ratio, stronger electromagnetic shielding performance for its smaller maximum aperture, and less degradation of imaging quality for its lower ratio and uniform distribution of high order diffraction energy. It is therefore concluded that this kind of ring mesh can be used as high-pass filters to provide electromagnetic shielding of optical transparent elements.

40 CFR Appendix D to Subpart S of... - Steady-State Short Test Equipment

Code of Federal Regulations, 2011 CFR

2011-07-01

... range of low scale, for five minutes without adjustment. (7) Electromagnetic isolation and interference. Electromagnetic signals found in an automotive service environment shall not cause malfunctions or changes in the... vary as a result of electromagnetic radiation and induction devices normally found in the automotive...

40 CFR Appendix D to Subpart S of... - Steady-State Short Test Equipment

Code of Federal Regulations, 2013 CFR

2013-07-01

... range of low scale, for five minutes without adjustment. (7) Electromagnetic isolation and interference. Electromagnetic signals found in an automotive service environment shall not cause malfunctions or changes in the... vary as a result of electromagnetic radiation and induction devices normally found in the automotive...

40 CFR Appendix D to Subpart S of... - Steady-State Short Test Equipment

Code of Federal Regulations, 2014 CFR

2014-07-01

... range of low scale, for five minutes without adjustment. (7) Electromagnetic isolation and interference. Electromagnetic signals found in an automotive service environment shall not cause malfunctions or changes in the... vary as a result of electromagnetic radiation and induction devices normally found in the automotive...

40 CFR Appendix D to Subpart S of... - Steady-State Short Test Equipment

Code of Federal Regulations, 2010 CFR

2010-07-01

... range of low scale, for five minutes without adjustment. (7) Electromagnetic isolation and interference. Electromagnetic signals found in an automotive service environment shall not cause malfunctions or changes in the... vary as a result of electromagnetic radiation and induction devices normally found in the automotive...

40 CFR Appendix D to Subpart S of... - Steady-State Short Test Equipment

Code of Federal Regulations, 2012 CFR

2012-07-01

... range of low scale, for five minutes without adjustment. (7) Electromagnetic isolation and interference. Electromagnetic signals found in an automotive service environment shall not cause malfunctions or changes in the... vary as a result of electromagnetic radiation and induction devices normally found in the automotive...

Characterization of printed planar electromagnetic coils using digital extrusion and roll-to-roll flexographic processes

NASA Astrophysics Data System (ADS)

Rickard, Scott

Electromagnets are a crucial component in a wide range of more complex electrical devices due to their ability to turn electrical energy into mechanical energy and vice versa. The trend for electronics becoming smaller and lighter has led to increased interest in using flat, planar electromagnetic coils, which have been shown to perform better at scaled down sizes. The two-dimensional geometry of a planar electromagnetic coil yields itself to be produced by a roll-to-roll additive manufacturing process. The emergence of the printed electronics field, which uses traditional printing processes to pattern functional inks, has led to new methods of mass-producing basic electrical components. The ability to print a planar electromagnetic coil using printed electronics could rival the traditional subtractive and semi-subtractive PCB process of manufacturing. The ability to print lightweight planar electromagnetic coils on flexible substrates could lead to their inclusion into intelligent packaging applications and could have specific use in actuating devices, transformers, and electromagnetic induction applications such as energy harvesting or wireless charging. In attempts to better understand the limitations of printing planar electromagnetic coils, the effect that the design parameters of the planar coils have on the achievable magnetic field strength were researched. A comparison between prototyping methods of digital extrusion and manufacturing scale flexographic printing are presented, discussing consistency in the printed coils and their performance in generating magnetic fields. A method to predict the performance of these planar coils is introduced to allow for design within required needs of an application. Results from the research include a demonstration of a printed coil being used in a flat speaker design, working off of actuating principles.

Advanced high-temperature electromagnetic pump

NASA Technical Reports Server (NTRS)

Gahan, J. W.; Powell, A. H.

1972-01-01

Three phase helical, electromagnetic induction pump for use as boiler feed pump in potassium Rankine-cycle power system is described. Techniques for fabricating components of pump are discussed. Specifications of pump are analyzed.

Separation of Electric Fields Into Potential and Inductive Parts, and Implications for Radial Diffusion

NASA Astrophysics Data System (ADS)

Chan, A. A.; Ilie, R.; Elkington, S. R.; Albert, J.; Huie, W.

2017-12-01

It has been traditional to separate radiation belt radial-diffusion coefficients into two contributions: an "electrostatic" diffusion coefficient, which is assumed to be due to a potential (non-inductive) electric field, and an "electromagnetic" diffusion coefficient , which is assumed to be due to the combined effect of an inductive electric field and the corresponding time-dependent magnetic field. One difficulty in implementing this separation when using magnetospheric fields obtained from measurements, or from MHD simulations, is that only the total electric field is given; the separation of the electric field into potential and inductive parts is not readily available. In this work we separate the electric field using a numerical method based on the Helmholtz decomposition of the total motional electric field calculated by the BATS-R-US MHD code. The inner boundary for the electric potential is based on the Ridley Ionospheric Model solution and we assume floating boundary conditions in the solar wind. Using different idealized solar wind drivers, including a solar wind density that is oscillating at a single frequency or with a broad spectrum of frequencies, we calculate potential and inductive electric fields, electric and magnetic power spectral densities, and corresponding radial diffusion coefficients. Simulations driven by idealized solar wind conditions show a clear separation of the potential and inductive contributions to the power spectral densities and diffusion coefficients. Simulations with more realistic solar wind drivers are underway to better assess the use of electrostatic and electromagnetic diffusion coefficients in understanding ULF wave-particle interactions in Earth's radiation belts.

Cone-shaped source characteristics and inductance effect of transient electromagnetic method

NASA Astrophysics Data System (ADS)

Yang, Hai-Yan; Li, Feng-Ping; Yue, Jian-Hua; Guo, Fu-Sheng; Liu, Xu-Hua; Zhang, Hua

2017-03-01

Small multi-turn coil devices are used with the transient electromagnetic method (TEM) in areas with limited space, particularly in underground environments such as coal mines roadways and engineering tunnels, and for detecting shallow geological targets in environmental and engineering fields. However, the equipment involved has strong mutual inductance coupling, which causes a lengthy turn-offtime and a deep "blind zone". This study proposes a new transmitter device with a conical-shape source and derives the radius formula of each coil and the mutual inductance coefficient of the cone. According to primary field characteristics, results of the two fields created, calculation of the conical-shaped source in a uniform medium using theoretical analysis, and a comparison of the inductance of the new device with that of the multi-turn coil, show that inductance of the multi-turn coil is nine times greater than that of the conical source with the same equivalent magnetic moment of 926.1 A·m2. This indicates that the new source leads to a much shallower "blind zone." Furthermore, increasing the bottom radius and turn of the cone creates a larger mutual inductance but increasing the cone height results in a lower mutual inductance. Using the superposition principle, the primary and secondary magnetic fields for a conical source in a homogeneous medium are calculated; results indicate that the magnetic behavior of the cone is the same as that of the multi-turn coils, but the transient responses of the secondary field and the total field are more stronger than those of the multi-turn coils. To study the transient response characteristics using a cone-shaped source in a layered earth, a numerical filtering algorithm is then developed using the fast Hankel transform and the improved cosine transform, again using the superposition principle. During development, an average apparent resistivity inverted from the induced electromotive force using each coil is defined to represent the comprehensive resistivity of the conical source. To verify the forward calculation method, the transient responses of H type models and KH type models are calculated, and data are inverted using a "smoke ring" inversion. The results of inversion have good agreement with original models and show that the forward calculation method is effective. The results of this study provide an option for solving the problem of a deep "blind zone" and also provide a theoretical indicator for further research.

A Missile-Borne Angular Velocity Sensor Based on Triaxial Electromagnetic Induction Coils

PubMed Central

Li, Jian; Wu, Dan; Han, Yan

2016-01-01

Aiming to solve the problem of the limited measuring range for angular motion parameters of high-speed rotating projectiles in the field of guidance and control, a self-adaptive measurement method for angular motion parameters based on the electromagnetic induction principle is proposed. First, a framework with type bent “I-shape” is used to design triaxial coils in a mutually orthogonal way. Under the condition of high rotational speed of a projectile, the induction signal of the projectile moving across a geomagnetic field is acquired by using coils. Second, the frequency of the pulse signal is adjusted self-adaptively. Angular velocity and angular displacement are calculated in the form of periodic pulse counting and pulse accumulation, respectively. Finally, on the basis of that principle prototype of the sensor is researched and developed, performance of measuring angular motion parameters are tested on the sensor by semi-physical and physical simulation experiments, respectively. Experimental results demonstrate that the sensor has a wide measuring range of angular velocity from 1 rps to 100 rps with a measurement error of less than 0.3%, and the angular displacement measurement error is lower than 0.2°. The proposed method satisfies measurement requirements for high-speed rotating projectiles with an extremely high dynamic range of rotational speed and high precision, and has definite value to engineering applications in the fields of attitude determination and geomagnetic navigation. PMID:27706039

A Missile-Borne Angular Velocity Sensor Based on Triaxial Electromagnetic Induction Coils.

PubMed

Li, Jian; Wu, Dan; Han, Yan

2016-09-30

Aiming to solve the problem of the limited measuring range for angular motion parameters of high-speed rotating projectiles in the field of guidance and control, a self-adaptive measurement method for angular motion parameters based on the electromagnetic induction principle is proposed. First, a framework with type bent "I-shape" is used to design triaxial coils in a mutually orthogonal way. Under the condition of high rotational speed of a projectile, the induction signal of the projectile moving across a geomagnetic field is acquired by using coils. Second, the frequency of the pulse signal is adjusted self-adaptively. Angular velocity and angular displacement are calculated in the form of periodic pulse counting and pulse accumulation, respectively. Finally, on the basis of that principle prototype of the sensor is researched and developed, performance of measuring angular motion parameters are tested on the sensor by semi-physical and physical simulation experiments, respectively. Experimental results demonstrate that the sensor has a wide measuring range of angular velocity from 1 rps to 100 rps with a measurement error of less than 0.3%, and the angular displacement measurement error is lower than 0.2°. The proposed method satisfies measurement requirements for high-speed rotating projectiles with an extremely high dynamic range of rotational speed and high precision, and has definite value to engineering applications in the fields of attitude determination and geomagnetic navigation.

Ship-borne electromagnetic induction sounding of sea-ice thickness in the southern Sea of Okhotsk

NASA Astrophysics Data System (ADS)

Uto, Shotaro; Toyota, Takenobu; Shimoda, Haruhito; Tateyama, Kazutaka; Shirasawa, Kunio

Recent observations have revealed that dynamical thickening is dominant in the growth process of sea ice in the southern Sea of Okhotsk. That indicates the importance of understanding the nature of thick deformed ice in this area. The objective of the present paper is to establish a ship-based method for observing the thickness of deformed ice with reasonable accuracy. Since February 2003, one of the authors has engaged in the core sampling using a small basket from the icebreaker Soya. Based on these results, we developed a new model which expressed the internal structure of pack ice in the southern Sea of Okhotsk, as a one-dimensional multilayered structure. Since 2004, the electromagnetic (EM) inductive sounding of sea-ice thickness has been conducted on board Soya. By combining the model and theoretical calculations, a new algorithm was developed for transforming the output of the EM inductive instrument to ice + snow thickness (total thickness). Comparison with total thickness by drillhole observations showed fair agreement. The probability density functions of total thickness in 2004 and 2005 showed some difference, which reflected the difference of fractions of thick deformed ice.

Experimenting with wires, batteries, bulbs and the induction coil: Narratives of teaching and learning physics in the electrical investigations of Laura, David, Jamie, myself and the nineteenth century experimenters. Our developments and instruments

NASA Astrophysics Data System (ADS)

Cavicchi, Elizabeth Mary

Physics is conventionally taught as a fixed curriculum which students must master. This thesis changes that: curriculum emerges from what learners try and question in experiments they invent. The thesis narrates: three adult students exploring wires, batteries and bulbs with me as teacher; nineteenth century investigations of electromagnetism; my laboratory work replicating historic instruments. In each case, learning arose through activity with materials. Evidences of this are analyzed within narratives and reflections. I used teaching-research, a method developed by Duckworth from Piaget's clinical interviewing, to research and simultaneously extend students' evolving understandings. What I learned through questioning students informed my next interactions; what they learned extended their experimenting. Similarly, I researched historical accounts interactively: improvising experiments to develop my understandings. Studying my own learning deepened my interpretations of students' learning. My students Laura, David and Jamie experimented by: soldering bulbs to wires, making series and parallel circuits, inserting resistive wire that dimmed bulbs, conducting electricity through salt water They noticed bulb brightness and battery heat, compared electricity's paths, questioned how voltage and current relate. They inferred electricity's effects manifest magnitudes of material properties. They found their experiences while learning were inseparable from what they learned. I researched investigations connected with Cavendish's leather fish, Galvani's frogs, Schweigger's wire spiraled around a compass needle, Henry's electromagnets, Faraday's induction ring, induction devices of Page, Callan, Hearder. Experimentally, I made galvanometers, electromagnets, induction rings, induction coil. I observed effects of electromagnetism, internal resistance, induced sparking. Across these investigations, learning developed with instrumental innovations; confusions were productive for further explorations. This thesis has implications for profoundly changing physics instruction. Physics education research seeks to supplant students' 'misconceptions' with correct explanations; by contrast, this thesis shows that students' original thinking provides their beginnings for moving to new understandings. Students and historic experimenters form and reform new, tentative understandings through many engagements with phenomena. As learners' questioning deepens in detail, its inclusiveness broadens. Evolving understandings are unique and consistent with nature. Wonder empowers continued learning. This thesis is a resource to inspire teachers in exploring the many possibilities within their learning, their students' learning, and physical phenomena.

Efficiency Measurement Using a Motor-Dynamo Module

ERIC Educational Resources Information Center

Ng, Pun-hon; Wong, Siu-ling; Mak, Se-yuen

2009-01-01

In this article, we describe a simple method which can be used to measure the efficiency of a low power dc motor, a motor-converted dynamo and a coupled motor-dynamo module as a function of the speed of rotation. The result can also be used to verify Faraday's law of electromagnetic induction. (Contains 1 table and 8 figures.)

Demonstration of ROV-based Underwater Electromagnetic Array Technology

DTIC Science & Technology

2017-05-25

Volume Magnetic Source Model that Was Modified to Address EM Propagation through a Conductive Seawater Medium...16  Figure 7. Still Shots of the Integrated ROV- EM System (left) and the EM Sensor (right) Performing Bottom Following...of Defense DVL Doppler Velocity Log E Easting EOD Explosive Ordnance Disposal EM Electromagnetic EMI Electromagnetic Induction EMF

Use of electromagnetic induction methods to monitor remediation at the University of Connecticut landfill: 2004–2011

USGS Publications Warehouse

Johnson, Carole D.; White, Eric A.; Joesten, Peter K.

2012-01-01

Time‐lapse geophysical surveys using frequency‐domain electromagnetics (FDEM) can indirectly measure time‐varying hydrologic parameters such as fluid saturation or solute concentration. Monitoring of these processes provides insight into aquifer properties and the effectiveness of constructed controls (such as leachate interceptor trenches), as well as aquifer responses to natural or induced stresses. At the University of Connecticut landfill, noninvasive, electromagnetic induction (EMI) methods were used to monitor changes in subsurface electrical conductivity that were related to the landfill‐closure activities. After the landfill was closed, EMI methods were used to monitor changes in water saturation and water quality. As part of a long‐term monitoring plan to observe changes associated with closure, redevelopment, and remediation of the former landfill, EMI data were collected to supplement information from groundwater samples collected in wells to the south and north of the landfill. In comparison to single‐point measurements that could have been collected by conventional installation of additional monitoring wells, the EMI methods provided increased spatial coverage, and were less invasive and therefore less destructive to the wetland north of the landfill. To monitor effects of closure activities on the subsurface conductivity, EMI measurements were collected from 2004 to 2011 along discrete transects north and south of the landfill prior to, during, and after the landfill closure. In general, the results indicated an overall decline in subsurface electrical conductivity with time and with distance from the former landfill. This decline in electrical conductivity indicated that the closure and remediation efforts reduced the amount of leachate that originated from the landfill and that entered the drainages to the north and south of the landfill.

Transcranial magnetic stimulation assisted by neuronavigation of magnetic resonance images

NASA Astrophysics Data System (ADS)

Viesca, N. Angeline; Alcauter, S. Sarael; Barrios, A. Fernando; González, O. Jorge J.; Márquez, F. Jorge A.

2012-10-01

Technological advance has improved the way scientists and doctors can learn about the brain and treat different disorders. A non-invasive method used for this is Transcranial Magnetic Stimulation (TMS) based on neuron excitation by electromagnetic induction. Combining this method with functional Magnetic Resonance Images (fMRI), it is intended to improve the localization technique of cortical brain structures by designing an extracranial localization system, based on Alcauter et al. work.

Contactless Inductive Bubble Detection in a Liquid Metal Flow

PubMed Central

Gundrum, Thomas; Büttner, Philipp; Dekdouk, Bachir; Peyton, Anthony; Wondrak, Thomas; Galindo, Vladimir; Eckert, Sven

2016-01-01

The detection of bubbles in liquid metals is important for many technical applications. The opaqueness and the high temperature of liquid metals set high demands on the measurement system. The high electrical conductivity of the liquid metal can be exploited for contactless methods based on electromagnetic induction. We will present a measurement system which consists of one excitation coil and a pickup coil system on the opposite sides of the pipe. With this sensor we were able to detect bubbles in a sodium flow inside a stainless steel pipe and bubbles in a column filled with a liquid Gallium alloy. PMID:26751444

A fully-implicit Particle-In-Cell Monte Carlo Collision code for the simulation of inductively coupled plasmas

NASA Astrophysics Data System (ADS)

Mattei, S.; Nishida, K.; Onai, M.; Lettry, J.; Tran, M. Q.; Hatayama, A.

2017-12-01

We present a fully-implicit electromagnetic Particle-In-Cell Monte Carlo collision code, called NINJA, written for the simulation of inductively coupled plasmas. NINJA employs a kinetic enslaved Jacobian-Free Newton Krylov method to solve self-consistently the interaction between the electromagnetic field generated by the radio-frequency coil and the plasma response. The simulated plasma includes a kinetic description of charged and neutral species as well as the collision processes between them. The algorithm allows simulations with cell sizes much larger than the Debye length and time steps in excess of the Courant-Friedrichs-Lewy condition whilst preserving the conservation of the total energy. The code is applied to the simulation of the plasma discharge of the Linac4 H- ion source at CERN. Simulation results of plasma density, temperature and EEDF are discussed and compared with optical emission spectroscopy measurements. A systematic study of the energy conservation as a function of the numerical parameters is presented.

Integration of GIS, Electromagnetic and Electrical Methods in the Delimitation of Groundwater Polluted by Effluent Discharge (Salamanca, Spain): A Case Study.

PubMed

Montes, Rubén Vidal; Martínez-Graña, Antonio Miguel; Martínez Catalán, José Ramón; Arribas, Puy Ayarza; Sánchez San Román, Francisco Javier; Zazo, Caridad

2017-11-10

The present work envisages the possible geometry of a contaminated plume of groundwater near hospital facilities by combining GIS (Geographic Information System) and geophysical methods. The rock underlying the soil and thin sedimentary cover of the study area is moderately fractured quartzite, which makes aquifers vulnerable to pollution. The GIS methodology is used to calculate the area that would be affected by the effluent source of residual water, based on algorithms that consider ground surface mapping (slopes, orientations, accumulated costs and cost per distance). Geophysical methods (electromagnetic induction and electric resistivity tomography) use changes in the electrical conductivity or resistivity of the subsurface to determine the geometry of the discharge and the degree of contamination. The model presented would allow a preliminary investigation regarding potential corrective measures.

Integration of GIS, Electromagnetic and Electrical Methods in the Delimitation of Groundwater Polluted by Effluent Discharge (Salamanca, Spain): A Case Study

PubMed Central

Montes, Rubén Vidal; Sánchez San Román, Francisco Javier; Zazo, Caridad

2017-01-01

The present work envisages the possible geometry of a contaminated plume of groundwater near hospital facilities by combining GIS (Geographic Information System) and geophysical methods. The rock underlying the soil and thin sedimentary cover of the study area is moderately fractured quartzite, which makes aquifers vulnerable to pollution. The GIS methodology is used to calculate the area that would be affected by the effluent source of residual water, based on algorithms that consider ground surface mapping (slopes, orientations, accumulated costs and cost per distance). Geophysical methods (electromagnetic induction and electric resistivity tomography) use changes in the electrical conductivity or resistivity of the subsurface to determine the geometry of the discharge and the degree of contamination. The model presented would allow a preliminary investigation regarding potential corrective measures. PMID:29125556

Experimental Study for Reduction of Noises and Vibrations in Hermetic Type Compressor

NASA Astrophysics Data System (ADS)

Sano, Kiyoshi; Kawahara, Sadao; Akazawa, Teruyuki; Ishii, Noriaki

A brushless DC motor with a permanent magnet rotor has been adopted for a scroll compressor for domestic-use air-conditioners because of a demand for compressor high efficiency. A waveform of the driving voltage in the inverter power supply unit is chopped by the PWM signal. Its duty ratio is increased/decreased to control the DC voltage in order to provide a wide range of rotation frequencies for the compressor. The driving voltage includes the carrier frequency and its harmonic components, which produce an electro-magnetic force in the moter, resulting in high electro-magnetic noise. In the present report, the author clarifies the relationships between the noise and the waveform of driving voltage and frequency response function of the motor. A method to improve the frequency response function by changing the stator shape in order to reduce electro-magnetic noise is presented. Subsequently, the influence on electro-magnetic noise from the waveform of driving voltage is examined. Furthermore, the electro-magnetic noises during inverter driving of an induction motor are presented.

Torque-mixing magnetic resonance spectroscopy (Conference Presentation)

NASA Astrophysics Data System (ADS)

Losby, Joseph; Fani Sani, Fatemeh; Grandmont, Dylan T.; Diao, Zhu; Belov, Miro; Burgess, Jacob A.; Compton, Shawn R.; Hiebert, Wayne K.; Vick, Doug; Mohammad, Kaveh; Salimi, Elham; Bridges, Gregory E.; Thomson, Douglas J.; Freeman, Mark R.

2016-10-01

An optomechanical platform for magnetic resonance spectroscopy will be presented. The method relies on frequency mixing of orthogonal RF fields to yield a torque amplitude (arising from the transverse component of a precessing dipole moment, in analogy to magnetic resonance detection by electromagnetic induction) on a miniaturized resonant mechanical torsion sensor. In contrast to induction, the method is fully broadband and allows for simultaneous observation of the equilibrium net magnetic moment alongside the associated magnetization dynamics. To illustrate the method, comprehensive electron spin resonance spectra of a mesoscopic, single-crystal YIG disk at room temperature will be presented, along with situations where torque spectroscopy can offer complimentary information to existing magnetic resonance detection techniques. The authors are very grateful for support from NSERC, CRC, AITF, and NINT. Reference: Science 350, 798 (2015).

Electromagnetic containerless processing requirements and recommended facility concept and capabilities for space lab

NASA Technical Reports Server (NTRS)

Frost, R. T.; Bloom, H. L.; Napaluch, L. J.; Stockhoff, E. H.; Wouch, G.

1974-01-01

Containerless melting, reaction, and solidification experiments and processes which potentially can lead to new understanding of material science and production of new or improved materials in the weightless space environment are reviewed in terms of planning for spacelab. Most of the experiments and processes discussed are amenable to the employment of electromagnetic position control and electromagnetic induction or electron beam heating and melting. The spectrum of relevant properties of materials, which determine requirements for a space laboratory electromagnetic containerless processing facility are reviewed. Appropriate distributions and associated coil structures are analyzed and compared on the basis of efficiency, for providing the functions of position sensing, control, and induction heating. Several coil systems are found capable of providing these functions. Exchangeable modular coils in appropriate sizes are recommended to achieve the maximum power efficiencies, for a wide range of specimen sizes and resistivities, in order to conserve total facility power.

Use of Permanent Magnets in Electromagnetic Facilities for the Treatment of Aluminum Alloys

NASA Astrophysics Data System (ADS)

Beinerts, Toms; Bojarevičs, Andris; Bucenieks, Imants; Gelfgat, Yuri; Kaldre, Imants

2016-06-01

The possibility of applying the electromagnetic induction pump with permanent magnets for the transportation and stirring of aluminum melts in metallurgical furnaces is investigated. The electromagnetic and hydraulic characteristics of the pump have been investigated theoretically and experimentally with regard to its position in the furnace. The results of the experiments performed with a model in a eutectic InGaSn melt are in good agreement with the calculation data. Extrapolation of the experimental results on the physical characteristics of aluminum melts allows recommending such pumps for contactless control of motion and heat/mass transfer in aluminum melts in different technological processes. A high temperature and the aggressive properties of aluminum alloys make it complicated to use different mechanical devices to solve technological problems, such as liquid metal transportation, dosing, stirring, etc. In this case, any device units or elements moving in or contacting with the melt suffer from corrosion polluting the melt. Therefore, of more importance and topicality are contactless electromagnetic methods for processing of molten metals.

Sensors for noncontact vibration diagnostics in rotating machinery

NASA Astrophysics Data System (ADS)

Procházka, Pavel

2016-06-01

The paper deals with electromagnetic sensors for noncontact vibration diagnostics in rotating machinery. The sensors were designed for operational measurements in turbomachinery by means of the tip-timing method. The main properties of eddy-current, Hall effect, induction and magnetoresistive sensors are described and compared. Possible arrangements of the experimental systems for static and dynamic calibration of the sensors are suggested and discussed.

The application of magnetic gradiometry and electromagnetic induction at a former radioactive waste disposal site.

PubMed

Rucker, Dale Franklin

2010-04-01

A former radioactive waste disposal site is surveyed with two non-intrusive geophysical techniques, including magnetic gradiometry and electromagnetic induction. Data were gathered over the site by towing the geophysical equipment mounted to a non-electrically conductive and non-magnetic fibre-glass cart. Magnetic gradiometry, which detects the location of ferromagnetic material, including iron and steel, was used to map the existence of a previously unknown buried pipeline formerly used in the delivery of liquid waste to a number of surface disposal trenches and concrete vaults. The existence of a possible pipeline is reinforced by historical engineering drawing and photographs. The electromagnetic induction (EMI) technique was used to map areas of high and low electrical conductivity, which coincide with the magnetic gradiometry data. The EMI also provided information on areas of high electrical conductivity unrelated to a pipeline network. Both data sets demonstrate the usefulness of surface geophysical surveillance techniques to minimize the risk of exposure in the event of future remediation efforts.

A linearly controlled direct-current power source for high-current inductive loads in a magnetic suspension wind tunnel

NASA Technical Reports Server (NTRS)

Tripp, John S.; Daniels, Taumi S.

1990-01-01

The NASA Langley 6 inch magnetic suspension and balance system (MSBS) requires an independently controlled bidirectional DC power source for each of six positioning electromagnets. These electromagnets provide five-degree-of-freedom control over a suspended aerodynamic test model. Existing power equipment, which employs resistance coupled thyratron controlled rectifiers as well as AC to DC motor generator converters, is obsolete, inefficient, and unreliable. A replacement six phase bidirectional controlled bridge rectifier is proposed, which employs power MOSFET switches sequenced by hybrid analog/digital circuits. Full load efficiency is 80 percent compared to 25 percent for the resistance coupled thyratron system. Current feedback provides high control linearity, adjustable current limiting, and current overload protection. A quenching circuit suppresses inductive voltage impulses. It is shown that 20 kHz interference from positioning magnet power into MSBS electromagnetic model position sensors results predominantly from capacitively coupled electric fields. Hence, proper shielding and grounding techniques are necessary. Inductively coupled magnetic interference is negligible.

Flow-field differences and electromagnetic-field properties of air and N2 inductively coupled plasmas

NASA Astrophysics Data System (ADS)

Yu, Minghao; Yamada, Kazuhiko; Takahashi, Yusuke; Liu, Kai; Zhao, Tong

2016-12-01

A numerical model for simulating air and nitrogen inductively coupled plasmas (ICPs) was developed considering thermochemical nonequilibrium and the third-order electron transport properties. A modified far-field electromagnetic model was introduced and tightly coupled with the flow field equations to describe the Joule heating and inductive discharge phenomena. In total, 11 species and 49 chemical reactions of air, which include 5 species and 8 chemical reactions of nitrogen, were employed to model the chemical reaction process. The internal energy transfers among translational, vibrational, rotational, and electronic energy modes of chemical species were taken into account to study thermal nonequilibrium effects. The low-Reynolds number Abe-Kondoh-Nagano k-ɛ turbulence model was employed to consider the turbulent heat transfer. In this study, the fundamental characteristics of an ICP flow, such as the weak ionization, high temperature but low velocity in the torch, and wide area of the plasma plume, were reproduced by the developed numerical model. The flow field differences between the air and nitrogen ICP flows inside the 10-kW ICP wind tunnel were made clear. The interactions between the electromagnetic and flow fields were also revealed for an inductive discharge.

Maxwell's inductions from Faraday's induction law

NASA Astrophysics Data System (ADS)

Redžić, D. V.

2018-03-01

In article 598 of his Treatise on Electricity and Magnetism (Maxwell 1891 A Treatise on Electricity and Magnetism (Oxford: Clarendon)), Maxwell gives a seminal analysis of Faraday's law of electromagnetic induction. We present a detailed account of the analysis, attempting to reconstruct the missing steps, and discuss some related matters.

ELECTROMAGNETIC AND ELECTROSTATIC GENERATORS: ANNOTATED BIBLIOGRAPHY.

DTIC Science & Technology

generator with split poles, ultrasonic-frequency generator, unipolar generator, single-phase micromotors , synchronous motor, asynchronous motor...asymmetrical rotor, magnetic circuit, dc micromotors , circuit for the automatic control of synchronized induction motors, induction torque micromotors , electric

Advanced Measurement Devices for the Microgravity Electromagnetic Levitation Facility EML

NASA Technical Reports Server (NTRS)

Brillo, Jurgen; Fritze, Holger; Lohofer, Georg; Schulz, Michal; Stenzel, Christian

2012-01-01

This paper reports on two advanced measurement devices for the microgravity electromagnetic levitation facility (EML), which is currently under construction for the use onboard the "International Space Station (ISS)": the "Sample Coupling Electronics (SCE)" and the "Oxygen Sensing and Control Unit (OSC)". The SCE measures by a contactless, inductive method the electrical resistivity and the diameter of a spherical levitated metallic droplet by evaluating the voltage and electrical current applied to the levitation coil. The necessity of the OSC comes from the insight that properties like surface tension or, eventually, viscosity cannot seriously be determined by the oscillating drop method in the EML facility without knowing the conditions of the surrounding atmosphere. In the following both measurement devices are explained and laboratory test results are presented.

Compact, Low-Noise Magnetic Sensor with Fluxgate (DC) and Induction (AC) Modes of Operation

DTIC Science & Technology

2009-07-01

induction sensor and the fluxgate magnetometer . ......................................... 2 Figure 3.1 - Impulse response of a 4” long coil (#6...Block diagram of the Year 2, Task 2 fluxgate magnetometer . ................................... 6 Figure 3.3 - FIS-prototype magnetic-field...and demonstrated an innovative dual-mode, fluxgate -induction sensor (FIS) that combines a fluxgate magnetometer and an electromagnetic (EM) induction

Magnetic antenna using metallic glass

NASA Technical Reports Server (NTRS)

Desch, Michael D. (Inventor); Farrell, William M. (Inventor); Houser, Jeffrey G. (Inventor)

1996-01-01

A lightweight search-coil antenna or sensor assembly for detecting magnetic fields and including a multi-turn electromagnetic induction coil wound on a spool type coil form through which is inserted an elongated coil loading member comprised of metallic glass material wrapped around a dielectric rod. The dielectric rod consists of a plastic or a wooden dowel having a length which is relatively larger than its thickness so as to provide a large length-to-diameter ratio. A tri-axial configuration includes a housing in which is located three substantially identical mutually orthogonal electromagnetic induction coil assemblies of the type described above wherein each of the assemblies include an electromagnetic coil wound on a dielectric spool with an elongated metallic glass coil loading member projecting therethrough.

Assisted of electromagnetic fields in glucose production from cassava stems

NASA Astrophysics Data System (ADS)

Lismeri, Lia; Haryati, Sri; Djoni Bustan, M.; Darni, Yuli

2018-03-01

Decrease in fossil fuel reserves that led to high price has become major problem in many countries around the world. To acquire the sustainability of energy reserves, the renewable energies obtained from plant biomass will therefore have to play an increasing role in fulfilling energy demand throughout the century. Renewable energy source must be explored by innovative techniques which is safe to the environment and low in energy consumptions. This research conducted to produce glucose from cassava stems assisted by electromagnetic field inductions process. The parameters used in this research were pretreatment solvent, concentration, temperature and electrical currents. The electromagnetic field inductions could be applied to increase glucose productivity with the maximum yield of glucose was 47.43%.

Scaling and characterisation of a 2-DoF velocity amplified electromagnetic vibration energy harvester

NASA Astrophysics Data System (ADS)

O’Donoghue, D.; Frizzell, R.; Punch, J.

2018-07-01

Vibration energy harvesters (VEHs) offer an alternative to batteries for the autonomous operation of low-power electronics. Understanding the influence of scaling on VEHs is of great importance in the design of reduced scale harvesters. The nonlinear harvesters investigated here employ velocity amplification, a technique used to increase velocity through impacts, to improve the power output of multiple-degree-of-freedom VEHs, compared to linear resonators. Such harvesters, employing electromagnetic induction, are referred to as velocity amplified electromagnetic generators (VAEGs), with gains in power achieved by increasing the relative velocity between the magnet and coil in the transducer. The influence of scaling on a nonlinear 2-DoF VAEG is presented. Due to the increased complexity of VAEGs, compared to linear systems, linear scaling theory cannot be directly applied to VAEGs. Therefore, a detailed nonlinear scaling method is utilised. Experimental and numerical methods are employed. This nonlinear scaling method can be used for analysing the scaling behaviour of all nonlinear electromagnetic VEHs. It is demonstrated that the electromagnetic coupling coefficient degrades more rapidly with scale for systems with larger displacement amplitudes, meaning that systems operating at low frequencies will scale poorly compared to those operating at higher frequencies. The load power of the 2-DoF VAEG is predicted to scale as {P}L\\propto {s}5.51 (s = volume1/3), suggesting that achieving high power densities in a VAEG with low device volume is extremely challenging.

Geophysical investigation of Red Devil mine using direct-current resistivity and electromagnetic induction, Red Devil, Alaska, August 2010

USGS Publications Warehouse

Burton, Bethany L.; Ball, Lyndsay B.

2011-01-01

Red Devil Mine, located in southwestern Alaska near the Village of Red Devil, was the state's largest producer of mercury and operated from 1933 to 1971. Throughout the lifespan of the mine, various generations of mills and retort buildings existed on both sides of Red Devil Creek, and the tailings and waste rock were deposited across the site. The mine was located on public Bureau of Land Management property, and the Bureau has begun site remediation by addressing mercury, arsenic, and antimony contamination caused by the minerals associated with the ore deposit (cinnabar, stibnite, realgar, and orpiment). In August 2010, the U.S. Geological Survey completed a geophysical survey at the site using direct-current resistivity and electromagnetic induction surface methods. Eight two-dimensional profiles and one three-dimensional grid of direct-current resistivity data as well as about 5.7 kilometers of electromagnetic induction profile data were acquired across the site. On the basis of the geophysical data and few available soil borings, there is not sufficient electrical or electromagnetic contrast to confidently distinguish between tailings, waste rock, and weathered bedrock. A water table is interpreted along the two-dimensional direct-current resistivity profiles based on correlation with monitoring well water levels and a relatively consistent decrease in resistivity typically at 2-6 meters depth. Three settling ponds used in the last few years of mine operation to capture silt and sand from a flotation ore processing technique possessed conductive values above the interpreted water level but more resistive values below the water level. The cause of the increased resistivity below the water table is unknown, but the increased resistivity may indicate that a secondary mechanism is affecting the resistivity structure under these ponds if the depth of the ponds is expected to extend below the water level. The electromagnetic induction data clearly identified the three monofills and indicate, in conjunction with the three-dimensional resistivity data, additional possible landfill features on the north side of Red Devil Creek. No obvious shallow feature was identified as a possible source for a spring that is feeding into Red Devil Creek from the north bank. However, a discrete, nearly vertical conductive feature observed on the direct-current resistivity line that passes within 5 meters of the spring may be worth investigating. Additional deep soil borings that better differentiate between tailings, waste rock, and weathered bedrock may be very useful in more confidently identifying these rock types in the direct-current resistivity data.

Design and testing of a coil-unit barrel for helical coil electromagnetic launcher

NASA Astrophysics Data System (ADS)

Yang, Dong; Liu, Zhenxiang; Shu, Ting; Yang, Lijia; Ouyang, Jianming

2018-01-01

A coil-unit barrel for a helical coil electromagnetic launcher is described. It provides better features of high structural strength and flexible adjustability. It is convenient to replace the damaged coil units and easy to adjust the number of turns in the stator coils due to the modular design. In our experiments, the highest velocity measured for a 4.5-kg projectile is 47.3 m/s and the mechanical reinforcement of the launcher could bear 35 kA peak current. The relationship between the energy conversion efficiency and the inductance gradient of the launcher is also studied. In the region of low inductance gradient, the efficiency is positively correlated with the inductance gradient. However, in the region of high inductance gradient, the inter-turn arc erosion becomes a major problem of limiting the efficiency and velocity of the launcher. This modular barrel allows further studies in the inter-turn arc and the variable inductance gradient helical coil launcher.

Design and testing of a coil-unit barrel for helical coil electromagnetic launcher.

PubMed

Yang, Dong; Liu, Zhenxiang; Shu, Ting; Yang, Lijia; Ouyang, Jianming

2018-01-01

A coil-unit barrel for a helical coil electromagnetic launcher is described. It provides better features of high structural strength and flexible adjustability. It is convenient to replace the damaged coil units and easy to adjust the number of turns in the stator coils due to the modular design. In our experiments, the highest velocity measured for a 4.5-kg projectile is 47.3 m/s and the mechanical reinforcement of the launcher could bear 35 kA peak current. The relationship between the energy conversion efficiency and the inductance gradient of the launcher is also studied. In the region of low inductance gradient, the efficiency is positively correlated with the inductance gradient. However, in the region of high inductance gradient, the inter-turn arc erosion becomes a major problem of limiting the efficiency and velocity of the launcher. This modular barrel allows further studies in the inter-turn arc and the variable inductance gradient helical coil launcher.

Physics Almost Saved the President! Electromagnetic Induction and the Assassination of James Garfield: A Teaching Opportunity in Introductory Physics

NASA Astrophysics Data System (ADS)

Overduin, James; Molloy, Dana; Selway, Jim

2014-03-01

Electromagnetic induction is probably one of the most challenging subjects for students in the introductory physics sequence, especially in algebra-based courses. Yet it is at the heart of many of the devices we rely on today. To help students grasp and retain the concept, we have put together a simple and dramatic classroom demonstration that combines sight and sound with a compelling personal story from U.S. history. Other classroom activities dealing with induction have been discussed in this journal, but we believe that this one will be especially likely to attract and retain student interest, particularly in courses geared toward medical, biological, and other non-physics majors.

Faraday's first dynamo: A retrospective

NASA Astrophysics Data System (ADS)

Smith, Glenn S.

2013-12-01

In the early 1830s, Michael Faraday performed his seminal experimental research on electromagnetic induction, in which he created the first electric dynamo—a machine for continuously converting rotational mechanical energy into electrical energy. His machine was a conducting disc, rotating between the poles of a permanent magnet, with the voltage/current obtained from brushes contacting the disc. In his first dynamo, the magnetic field was asymmetric with respect to the axis of the disc. This is to be contrasted with some of his later symmetric designs, which are the ones almost invariably discussed in textbooks on electromagnetism. In this paper, a theoretical analysis is developed for Faraday's first dynamo. From this analysis, the eddy currents in the disc and the open-circuit voltage for arbitrary positioning of the brushes are determined. The approximate analysis is verified by comparing theoretical results with measurements made on an experimental recreation of the dynamo. Quantitative results from the analysis are used to elucidate Faraday's qualitative observations, from which he learned so much about electromagnetic induction. For the asymmetric design, the eddy currents in the disc dissipate energy that makes the dynamo inefficient, prohibiting its use as a practical generator of electric power. Faraday's experiments with his first dynamo provided valuable insight into electromagnetic induction, and this insight was quickly used by others to design practical generators.

Electromagnetic Performance Calculation of HTS Linear Induction Motor for Rail Systems

NASA Astrophysics Data System (ADS)

Liu, Bin; Fang, Jin; Cao, Junci; Chen, Jie; Shu, Hang; Sheng, Long

2017-07-01

According to a high temperature superconducting (HTS) linear induction motor (LIM) designed for rail systems, the influence of electromagnetic parameters and mechanical structure parameters on the electromagnetic horizontal thrust, vertical force of HTS LIM and the maximum vertical magnetic field of HTS windings are analyzed. Through the research on the vertical field of HTS windings, the development regularity of the HTS LIM maximum input current with different stator frequency and different thickness value of the secondary conductive plate is obtained. The theoretical results are of great significance to analyze the stability of HTS LIM. Finally, based on theory analysis, HTS LIM test platform was built and the experiment was carried out with load. The experimental results show that the theoretical analysis is correct and reasonable.

Influence of groundwater on distribution of dwarf wedgemussels (Alasmidonta heterodon) in the upper reaches of the Delaware River, northeastern USA

USGS Publications Warehouse

Rosenberry, Donald O.; Briggs, Martin A.; Voytek, Emily B.; Lane, John W.

2016-01-01

The remaining populations of the endangered dwarf wedgemussel (DWM) (Alasmidonta heterodon) in the upper Delaware River, northeastern USA, were hypothesized to be located in areas of greater-than-normal groundwater discharge to the river. We combined physical (seepage meters, monitoring wells and piezometers), thermal (fiber-optic distributed temperature sensing, infrared, vertical bed-temperature profiling), and geophysical (electromagnetic-induction) methods at several spatial scales to characterize known DWM habitat and explore this hypothesis. Numerous springs were observed using visible and infrared imaging along the river banks at all three known DWM-populated areas, but not in adjacent areas where DWM were absent. Vertical and lateral groundwater gradients were toward the river along all three DWM-populated reaches, with median upward gradients 3 to 9 times larger than in adjacent reaches. Point-scale seepage-meter measurements indicated that upward seepage across the riverbed was faster and more consistently upward at DWM-populated areas. Discrete and areally distributed riverbed-temperature measurements indicated numerous cold areas of groundwater discharge during warm summer months; all were within areas populated by DWM. Electromagnetic-induction measurements, which may indicate riverbed geology, showed patterning but little correlation between bulk streambed electromagnetic conductivity and areal distribution of DWM. In spite of complexity introduced by hyporheic exchange, multiple lines of research provide strong evidence that DWM are located within or directly downstream of areas of substantial focused groundwater discharge to the river. Broad scale thermal-reconnaissance methods (e.g., infrared) may be useful in locating and protecting other currently unknown mussel populations.

Agricultural Electricity. Electric Motors. Student Manual.

ERIC Educational Resources Information Center

Benson, Robert T.

Addressed to the student, this manual, which includes supplementary diagrams, discusses the following topics and principles: Electromagnetic fields, electromagnets, parts of an electric motor, determining speed of an electric motor, types of electric motors in common use (split-phase, capacitor, repulsion-induction, three-phase), the electric…

Multi-frequency Electromagnetic Induction Survey for Archaeological Prospection: Approach and Results in Han Hangu Pass and Xishan Yang in China

NASA Astrophysics Data System (ADS)

Tang, Panpan; Chen, Fulong; Jiang, Aihui; Zhou, Wei; Wang, Hongchao; Leucci, Giovanni; de Giorgi, Lara; Sileo, Maria; Luo, Rupeng; Lasaponara, Rosa; Masini, Nicola

2018-04-01

This study presents the potential of multi-frequency electromagnetic induction (EMI) in archaeology. EMI is currently less employed for archaeological prospection with respect to other geophysical techniques. It is capable of identifying shallow subsurface relics by simultaneously measuring the apparent electrical conductivity (ECa) and apparent magnetic susceptibility (MSa). Moreover, frequency sounding is able to quantify the depths and vertical shapes of buried structures. In this study, EMI surveys with five frequencies were performed at two heritage sites with different geological conditions: Han Hangu Pass characterized by cinnamon soil and Xishan Yang by sandy loams. In the first site, high ECa values were observed with variations in depth correlated to archaeological remains. Moreover, electromagnetic anomalies related to an ancient road and five kiln caves were identified. In the second site, an ancient tomb, indicating extremely low ECa and high MSa, was discovered. Its electromagnetic properties are attributed to the cavity and ferroferric oxides.

A Simple and Accurate Analysis of Conductivity Loss in Millimeter-Wave Helical Slow-Wave Structures

NASA Astrophysics Data System (ADS)

Datta, S. K.; Kumar, Lalit; Basu, B. N.

2009-04-01

Electromagnetic field analysis of a helix slow-wave structure was carried out and a closed form expression was derived for the inductance per unit length of the transmission-line equivalent circuit of the structure, taking into account the actual helix tape dimensions and surface current on the helix over the actual metallic area of the tape. The expression of the inductance per unit length, thus obtained, was used for estimating the increment in the inductance per unit length caused due to penetration of the magnetic flux into the conducting surfaces following Wheeler’s incremental inductance rule, which was subsequently interpreted for the attenuation constant of the propagating structure. The analysis was computationally simple and accurate, and accrues the accuracy of 3D electromagnetic analysis by allowing the use of dispersion characteristics obtainable from any standard electromagnetic modeling. The approach was benchmarked against measurement for two practical structures, and excellent agreement was observed. The analysis was subsequently applied to demonstrate the effects of conductivity on the attenuation constant of a typical broadband millimeter-wave helical slow-wave structure with respect to helix materials and copper plating on the helix, surface finish of the helix, dielectric loading effect and effect of high temperature operation - a comparative study of various such aspects are covered.

Influence of Vertical Electromagnetic Brake on the Steel/Slag Interface Behavior in a Slab Mold

NASA Astrophysics Data System (ADS)

Li, Zhuang; Wang, Engang; Zhang, Lintao; Xu, Yu; Deng, Anyuan

2017-10-01

The steel/slag interface behavior under a new type of electromagnetic brake (EMBr), vertical electromagnetic brake (V-EMBr), was investigated. The influence of the magnetic induction intensity, the submerged entry nozzle (SEN) immersion depth, and the port angle of the SEN are investigated numerically. The effect of magnetic induction intensity on the meniscus fluctuation of molten alloy is further studied by the experiments. The results show that the meniscus fluctuation is depressed as the magnetic induction intensity is increased, especially for the region in the vicinity of the narrow face of the slab mold. This result is validated by the following experiments. For the influence of the SEN immersion depth and the port angle, the results show that the meniscus fluctuation is suppressed as the values of the immersion depth and the port angle are increased (absolute values for the port angle). However, the influence of the immersion depth and the port angle are not as sensitive as those in the other type of EMBr, e.g., EMBr Ruler. The industrial application of V-EMBr could benefit from this result.

Pulsed magnetic field excitation sensitivity of match-type electric blasting caps

NASA Astrophysics Data System (ADS)

Parson, Jonathan; Dickens, James; Walter, John; Neuber, Andreas A.

2010-10-01

This paper presents a study on energy deposition and electromagnetic compatibility of match-type electroexplosive devices (EEDs), which recently have found more usage in pulsed power environments with high electromagnetic interference (EMI) background. The sensitivity of these devices makes them dangerous to intended and unintended radiation produced by devices commonly used in pulsed power environments. Match-type EEDs have been found to be susceptible to such low levels of energy (7-8 mJ) that safe operation of these EEDs is vital when in use near devices that produce high levels of pulsed EMI. The scope of this paper is to provide an investigation that incorporates results of similar studies to provide detonation characteristics of these EEDs. The three topics included in this study are sensitivity testing, modeling of the thermodynamic heat propagation, and electromagnetic compatibility from pulsed electromagnetic radiation. The thermodynamic joule heating of the primary explosive has been modeled by a solution to the 1D heat equation. A simple pulsed generator, Marx generator with an inductive load, was used for the electromagnetic compatibility assessment of the coupled field between the pulse generator and shorted EED. The results of the electromagnetic compatibility assessment relate the resistive, inductive, and capacitive components of the pulse generator to the area of the shorted EED.

Pulsed magnetic field excitation sensitivity of match-type electric blasting caps.

PubMed

Parson, Jonathan; Dickens, James; Walter, John; Neuber, Andreas A

2010-10-01

This paper presents a study on energy deposition and electromagnetic compatibility of match-type electroexplosive devices (EEDs), which recently have found more usage in pulsed power environments with high electromagnetic interference (EMI) background. The sensitivity of these devices makes them dangerous to intended and unintended radiation produced by devices commonly used in pulsed power environments. Match-type EEDs have been found to be susceptible to such low levels of energy (7-8 mJ) that safe operation of these EEDs is vital when in use near devices that produce high levels of pulsed EMI. The scope of this paper is to provide an investigation that incorporates results of similar studies to provide detonation characteristics of these EEDs. The three topics included in this study are sensitivity testing, modeling of the thermodynamic heat propagation, and electromagnetic compatibility from pulsed electromagnetic radiation. The thermodynamic joule heating of the primary explosive has been modeled by a solution to the 1D heat equation. A simple pulsed generator, Marx generator with an inductive load, was used for the electromagnetic compatibility assessment of the coupled field between the pulse generator and shorted EED. The results of the electromagnetic compatibility assessment relate the resistive, inductive, and capacitive components of the pulse generator to the area of the shorted EED.

Numerical and Experimental Investigation on the Attenuation of Electromagnetic Waves in Unmagnetized Plasmas Using Inductively Coupled Plasma Actuator

NASA Astrophysics Data System (ADS)

Lin, Min; Xu, Haojun; Wei, Xiaolong; Liang, Hua; Song, Huimin; Sun, Quan; Zhang, Yanhua

2015-10-01

The attenuation of electromagnetic (EM) waves in unmagnetized plasma generated by an inductively coupled plasma (ICP) actuator has been investigated both theoretically and experimentally. A numerical study is conducted to investigate the propagation of EM waves in multilayer plasma structures which cover a square flat plate. Experimentally, an ICP actuator with dimensions of 20 cm×20 cm×4 cm is designed to produce a steady plasma slab. The attenuation of EM waves in the plasma generated by the ICP actuator is measured by a reflectivity arch test method at incident waves of 2.3 GHz and 10.1 GHz, respectively. A contrastive analysis of calculated and measured results of these incident wave frequencies is presented, which suggests that the experiment accords well with our theory. As expected, the plasma slab generated by the ICP actuator can effectively attenuate the EM waves, which may have great potential application prospects in aircraft stealth. supported by National Natural Science Foundation of China (Nos. 51276197, 11472306 and 11402301)

Electromagnetic deep-probing (100-1000 KMS) of the Earth's interior from artificial satellites: Constraints on the regional emplacement of crustal resources

NASA Technical Reports Server (NTRS)

Hermance, J. F. (Principal Investigator)

1982-01-01

The two stages of analysis of MAGSAT magnetic data which are designed to evaluate electromagnetic induction effects are described. The first stage consists of comparison of data from contiguous orbit passes over large scale geologic boundaries, such as ocean-land interfaces, at several levels of magnetic disturbance. The purpose of these comparisons is to separate induction effects from effects of lithospheric magnetization. The procdure for reducing the data includes: (1) identifying and subtracting quiet time effects; (2) modelling and subtracting first order ring current effects; and (3) projecting an orbit track onto a map as a nearly straight line so it can serve as an axis on which to plot the corresponding orbit pass data in the context of geography. The second stage consists of comparison of MAGSAT data with standard hourly observatory data. The purpose is to constrain the time evolution of ionospheric and magnetospheric current systems. Qualitative features of the ground based dataset are discussed. Methods for reducing the ground based data are described.

Electromagnetic induction heating for single crystal graphene growth: morphology control by rapid heating and quenching

NASA Astrophysics Data System (ADS)

Wu, Chaoxing; Li, Fushan; Chen, Wei; Veeramalai, Chandrasekar Perumal; Ooi, Poh Choon; Guo, Tailiang

2015-03-01

The direct observation of single crystal graphene growth and its shape evolution is of fundamental importance to the understanding of graphene growth physicochemical mechanisms and the achievement of wafer-scale single crystalline graphene. Here we demonstrate the controlled formation of single crystal graphene with varying shapes, and directly observe the shape evolution of single crystal graphene by developing a localized-heating and rapid-quenching chemical vapor deposition (CVD) system based on electromagnetic induction heating. Importantly, rational control of circular, hexagonal, and dendritic single crystalline graphene domains can be readily obtained for the first time by changing the growth condition. Systematic studies suggest that the graphene nucleation only occurs during the initial stage, while the domain density is independent of the growth temperatures due to the surface-limiting effect. In addition, the direct observation of graphene domain shape evolution is employed for the identification of competing growth mechanisms including diffusion-limited, attachment-limited, and detachment-limited processes. Our study not only provides a novel method for morphology-controlled graphene synthesis, but also offers fundamental insights into the kinetics of single crystal graphene growth.

"Non-Contact Ultrasonic Treatment of Metals in a Magnetic Field"

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ludtka, Gerard Michael; Wilgen, John B; Kisner, Roger A

2007-01-01

A concept has been originated for non-contact ultrasonic treatment of metals based on the use of an induction coil located in a high-field superconducting magnet. An advantage of using a high magnetic field environment (> 9 T) is that this allows the induced surface current in the sample to be decreased proportionately. As a result, the incidental induction heating associated with the use of the EMAT (Electromagnetic Acoustical Transducer) is greatly reduced, which improves the energy efficiency of the EMAT approach. The method can be coupled with high-field magnetic processing, but can also be used where only ultrasonic treatment ismore » beneficial. In the proof-of-principle experiments, a high-field EMAT was used for non-contact ultrasonic processing of aluminum samples during solidification. The magnetic field for the EMAT was supplied by a high-field (20 Tesla) resistive magnet, and the current was provided by an induction coil. This resulted in a highly efficient EMAT that delivered 0.5 MPa (~5 atmospheres) of acoustic drive to the surface of the sample while coupling less than 100 watts of incidental induction heating. The exceptionally high energy efficiency of the electromagnetic transducer is due to the use of the high magnetic field, which reduces the current needed to achieve the same acoustic pressure. In these initial experiments, aluminum samples of A356 alloy were heated to the liquid state and allowed to solidify at a controlled cooling rate while subjected to the non-contact ultrasonic stimulation (0.5 MPa @ 165 kHz) provided by an induction coil located within the 200 mm (~8-inch) bore of a 20-T Bitter resistive magnet.« less

Coil design considerations for a high-frequency electromagnetic induction sensing instrument

NASA Astrophysics Data System (ADS)

Sigman, John B.; Barrowes, Benjamin E.; Wang, Yinlin; Bennett, Hollis J.; Simms, Janet E.; Yule, Donald E.; O'Neill, Kevin; Shubitidze, Fridon

2016-05-01

Intermediate electrical conductivity (IEC) materials (101S/m < σ < 104S/m), such as carbon fiber (CF), have recently been used to make smart bombs. In addition, homemade improvised explosive devices (IED) can be produced with low conducting materials (10-4S/m < σ < 1S/m), such as Ammonium Nitrate (AN). To collect unexploded ordnance (UXO) from military training ranges and thwart deadly IEDs, the US military has urgent need for technology capable of detection and identification of subsurface IEC objects. Recent analytical and numerical studies have showed that these targets exhibit characteristic quadrature response peaks at high induction frequencies (100kHz - 15MHz, the High Frequency Electromagnetic Induction (HFEMI) band), and they are not detectable with traditional ultra wideband (UWB) electromagnetic induction (EMI) metal detectors operating between 100Hz - 100kHz. Using the HFEMI band for induction sensing is not so simple as driving existing instruments at higher frequencies, though. At low frequency, EMI systems use more wire turns in transmit and receive coils to boost signal-to-noise ratios (SNR), but at higher frequencies, the transmitter current has non-uniform distribution along the coil length. These non-uniform currents change the spatial distribution of the primary magnetic field and disturb axial symmetry and thwart established approaches for inferring subsurface metallic object properties. This paper discusses engineering tradeoffs for sensing with a broader band of frequencies ever used for EMI sensing, with particular focus on coil geometries.

Thermoacoustic inductor for heavy oil extraction

NASA Astrophysics Data System (ADS)

Tyncherov, K. T.; Mukhametshin, V. Sh; Paderin, M. G.; Selivanova, M. V.; Shokurov, I. V.; Almukhametova, E. M.

2018-03-01

The problem of enhancing heavy oil reservoir performance is a matter of relevance for many years. Among the technologies aimed at solving this problem, the technology of the bottom-hole and well casing heating is the most interesting. This is a real possibility to transform thickened hydrocarbon into a recoverable state, as well as to solve the tasks of cleaning the borehole from asphaltenes, resins, and paraffin sediments. In both cases, the borehole area is generally warmed up and the product is then pumped out by the known techniques. The type of the equipment, the way of the well operation, the stage of reservoir development, physical and chemical properties of paraffin sediments, etc. are taken into consideration. In the article, basing on the electromagnetic induction method and the Joule effect, the advantages of induction heating compared to the traditional resistive and steam methods are presented. It is shown that under the induction exposure, the heat is not focused on the apparatus, but on heating the oily product. Basing on the method, a thermoacoustic inductor with unique technical characteristics has been developed.

Electromagnetic induction pump for pumping liquid metals and other conductive liquids

DOEpatents

Smither, R.K.

1993-05-11

An electromagnetic induction pump is described in which an electrically conductive liquid is made to flow by means of a force created by interaction of a permanent magnetic field and a DC current. The pump achieves high efficiency through combination of: powerful permanent magnet materials which provide a high strength field that is uniform and constant; steel tubing formed into a coil which is constructed to carry conducting liquids with minimal electrical resistance and heat; and application of a voltage to induce a DC current which continuously produces a force in the direction of the desired flow.

Electromagnetic induction pump for pumping liquid metals and other conductive liquids

DOEpatents

Smither, Robert K.

1993-01-01

An electromagnetic induction pump in which an electrically conductive liquid is made to flow by means of a force created by interaction of a permanent magnetic field and a DC current. The pump achieves high efficiency through combination of: powerful permanent magnet materials which provide a high strength field that is uniform and constant; steel tubing formed into a coil which is constructed to carry conducting liquids with minimal electrical resistance and heat; and application of a voltage to induce a DC current which continuously produces a force in the direction of the desired flow.

Subcritical Hopf Bifurcation and Stochastic Resonance of Electrical Activities in Neuron under Electromagnetic Induction

PubMed Central

Fu, Yu-Xuan; Kang, Yan-Mei; Xie, Yong

2018-01-01

The FitzHugh–Nagumo model is improved to consider the effect of the electromagnetic induction on single neuron. On the basis of investigating the Hopf bifurcation behavior of the improved model, stochastic resonance in the stochastic version is captured near the bifurcation point. It is revealed that a weak harmonic oscillation in the electromagnetic disturbance can be amplified through stochastic resonance, and it is the cooperative effect of random transition between the resting state and the large amplitude oscillating state that results in the resonant phenomenon. Using the noise dependence of the mean of interburst intervals, we essentially suggest a biologically feasible clue for detecting weak signal by means of neuron model with subcritical Hopf bifurcation. These observations should be helpful in understanding the influence of the magnetic field to neural electrical activity. PMID:29467642

Summary of sensor evaluation for the Fusion Electromagnetic Induction Experiment (FELIX)

NASA Astrophysics Data System (ADS)

Knott, M. J.

1982-08-01

As part of the First Wall/Blanket/Shield Engineering Test Program, a test bed called FELIX (fusion electromagnetic induction experiment) is under construction. Its purpose is to test, evaluate, and develop computer codes for the prediction of electromagnetically induced phenomenon in a magnetic environment modeling that of a fusion reaction. Crucial to this process is the sensing and recording of the various induced effects. Sensor evaluation for FELIX reached the point where most sensor types were evaluated and preliminary decisions are being made as to type and quantity for the initial FELIX experiments. These early experiments, the first, flat plate experiment in particular, will be aimed at testing the sensors as well as the pertinent theories involved. The reason for these evaluations, decisions, and proof tests is the harsh electrical and magnetic environment that FELIX presents.

Subcritical Hopf Bifurcation and Stochastic Resonance of Electrical Activities in Neuron under Electromagnetic Induction.

PubMed

Fu, Yu-Xuan; Kang, Yan-Mei; Xie, Yong

2018-01-01

The FitzHugh-Nagumo model is improved to consider the effect of the electromagnetic induction on single neuron. On the basis of investigating the Hopf bifurcation behavior of the improved model, stochastic resonance in the stochastic version is captured near the bifurcation point. It is revealed that a weak harmonic oscillation in the electromagnetic disturbance can be amplified through stochastic resonance, and it is the cooperative effect of random transition between the resting state and the large amplitude oscillating state that results in the resonant phenomenon. Using the noise dependence of the mean of interburst intervals, we essentially suggest a biologically feasible clue for detecting weak signal by means of neuron model with subcritical Hopf bifurcation. These observations should be helpful in understanding the influence of the magnetic field to neural electrical activity.

Monitoring scale-specific and temporal variation in electromagnetic conductivity images

USDA-ARS?s Scientific Manuscript database

In the semi-arid and arid landscapes of southwest USA, irrigation sustains agricultural activity; however, there are increasing demands on water resources. As such spatial temporal variation of soil moisture needs to be monitored. One way to do this is to use electromagnetic (EM) induction instrumen...

Influence of the aging process on the dealloying activity of an induction salt bath

NASA Astrophysics Data System (ADS)

Simonenko, A. N.

1992-12-01

The process of dealloying of the surface of high-alloy steels in heating in induction salt baths with a graphite crucible is neutralized by the process of carburizing and electrochemical interaction in a high-frequency electromagnetic field.

Electro-quasistatic analysis of an electrostatic induction micromotor using the cell method.

PubMed

Monzón-Verona, José Miguel; Santana-Martín, Francisco Jorge; García-Alonso, Santiago; Montiel-Nelson, Juan Antonio

2010-01-01

An electro-quasistatic analysis of an induction micromotor has been realized by using the Cell Method. We employed the direct Finite Formulation (FF) of the electromagnetic laws, hence, avoiding a further discretization. The Cell Method (CM) is used for solving the field equations at the entire domain (2D space) of the micromotor. We have reformulated the field laws in a direct FF and analyzed physical quantities to make explicit the relationship between magnitudes and laws. We applied a primal-dual barycentric discretization of the 2D space. The electric potential has been calculated on each node of the primal mesh using CM. For verification purpose, an analytical electric potential equation is introduced as reference. In frequency domain, results demonstrate the error in calculating potential quantity is neglected (<3‰). In time domain, the potential value in transient state tends to the steady state value.

Electro-Quasistatic Analysis of an Electrostatic Induction Micromotor Using the Cell Method

PubMed Central

Monzón-Verona, José Miguel; Santana-Martín, Francisco Jorge; García–Alonso, Santiago; Montiel-Nelson, Juan Antonio

2010-01-01

An electro-quasistatic analysis of an induction micromotor has been realized by using the Cell Method. We employed the direct Finite Formulation (FF) of the electromagnetic laws, hence, avoiding a further discretization. The Cell Method (CM) is used for solving the field equations at the entire domain (2D space) of the micromotor. We have reformulated the field laws in a direct FF and analyzed physical quantities to make explicit the relationship between magnitudes and laws. We applied a primal-dual barycentric discretization of the 2D space. The electric potential has been calculated on each node of the primal mesh using CM. For verification purpose, an analytical electric potential equation is introduced as reference. In frequency domain, results demonstrate the error in calculating potential quantity is neglected (<3‰). In time domain, the potential value in transient state tends to the steady state value. PMID:22163397

Correlation of Noise Signature to Pulsed Power Events at the HERMES III Accelerator.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lewis, Barbara; Joseph, Nathan Ryan; Salazar, Juan Diego

2016-11-01

The HERMES III accelerator, which is located at Sandia National Laboratories' Tech Area IV, is the largest pulsed gamma X-ray source in the world. The accelerator is made up of 20 inductive cavities that are charged to 1 MV each by complex pulsed power circuitry. The firing time of the machine components ranges between the microsecond and nanosecond timescales. This results in a variety of electromagnetic frequencies when the accelerator fires. Testing was done to identify the HERMES electromagnetic noise signal and to map it to the various accelerator trigger events. This report will show the measurement methods used tomore » capture the noise spectrum produced from the machine and correlate this noise signature with machine events.« less

The Study of Residual Voltage of Induction Motor and the Influence of Various Parameters on the Residual Voltage

NASA Astrophysics Data System (ADS)

Zhang, Shuping; Zhao, Chen; Tan, Weipu

2017-05-01

The majority important load of industrial area is mainly composed of induction motor, it is more common that induction motor becomes sluggishness and even tripping due to the lose of power supply or other malfunction in the practical work. In this paper, space vector method is used to establish a reduced order model of induction motor, and then study the changes of motor electromagnetic after losing electricity. Based on motion equations of the rotor and magnetic flux conservation principle, it uses mathematical methods to deduce the expression of rotor current, rotor flux, the stator flux and the residual voltage of stator side. In addition, relying on thermal power plants, it uses the actual data of power plants, takes DIgsilent software to simulate the residual voltage of motor after losing electricity. analyses the influence on the residual voltage with the changes of the moment of inertia, load ratio, initial size of slip and the load characteristic of induction motor. By analysis of these, it has a more detailed understanding about the changes of residual voltage in practical application, in additional, it is more beneficial to put into standby power supply safely and effectively, moreover, reduce the influence of the input process to the whole system.

Electric Field Feature of Moving Magnetic Field

NASA Astrophysics Data System (ADS)

Chen, You Jun

2001-05-01

A new fundamental relationship of electric field with magnetic field has been inferred from the fundamental experimental laws and theories of classical electromagnetics. It can be described as moving magnetic field has or gives electric feature. When a field with magnetic induction of B moves in the velocity of V, it will show electric field character, the electric field intensity E is E = B x V and the direction of E is in the direction of the vector B x V. It is improper to use the time-varying electromagnetics theories as the fundamental theory of the electromagnetics and group the electromagnetic field into static kind and time-varying kind for the static is relative to motional not only time-varying. The relationship of time variation of magnetic field induction or magnetic flux with electric field caused by magnetic field is fellowship not causality. Thus time-varying magnetic field can cause electric field is not a nature principle. Sometime the time variation of magnetic flux is equal to the negative electromotive force or the time variation of magnetic field induction is equal to the negative curl of electric field caused by magnetic field motion, but not always. And not all motion of magnetic field can cause time variation of magnetic field. Therefore Faraday-Lenz`s law can only be used as mathematics tool to calculate the quantity relation of the electricity with the magnetism in some case like the magnetic field moving in uniform medium. Faraday-Lenz`s law is unsuitable to be used in moving uniform magnetic field or there is magnetic shield. Key word: Motional magnetic field, Magnetic induction, Electric field intensity, Velocity, Faraday-Lenz’s law

Effect of 900 MHz Electromagnetic Radiation on the Induction of ROS in Human Peripheral Blood Mononuclear Cells

PubMed Central

Kazemi, E.; Mortazavi, S. M. J.; Ali-Ghanbari, A.; Sharifzadeh, S.; Ranjbaran, R.; Mostafavi-pour, Z.; Zal, F.; Haghani, M.

2015-01-01

Background Despite numerous studies over a decade, it still remains controversial about the biological effects of RF EMF emitted by mobile phone telephony. Objective Here we investigated the effect of 900 MHz GSM on the induction of oxidative stress and the level of intracellular reactive oxygen species (ROS) in human mononuclear cells, monocytes and lymphocytes as defence system cells. Method 6 ml Peripheral Blood samples were obtained from 13 healthy volunteers (21-30 year-old). Each sample was devided into 2 groups: one was exposed RF radiation emitted from a mobile phone simulator for 2 hour and the other used as control group which was not exposed to any fields. After that, mononuclear cells were isolated from peripheral blood by density gradient centrifugation in Ficoll-Paque. The intracellular ROS content in monocytes and lymphocytes was measured by the CM-H2DCFDA fluorescence probe using flowcytometry technique. Results Our results showed significant increase in  ROS production after exposure in population rich in monocytes. This effect was not significant in population rich in lymphocytes in comparison with non exposed cells. Conclusion The results obtained in this study clearly showed the oxidative stress induction capability of RF electromagnetic field in the portion of PBMCs mostly in monocytes, like the case of exposure to micro organisms, although the advantages or disadvantages of this effect should be evaluated. PMID:26396966

Magnetostriction measurement by four probe method

NASA Astrophysics Data System (ADS)

Dange, S. N.; Radha, S.

2018-04-01

The present paper describes the design and setting up of an indigenouslydevelopedmagnetostriction(MS) measurement setup using four probe method atroom temperature.A standard strain gauge is pasted with a special glue on the sample and its change in resistance with applied magnetic field is measured using KeithleyNanovoltmeter and Current source. An electromagnet with field upto 1.2 tesla is used to source the magnetic field. The sample is placed between the magnet poles using self designed and developed wooden probe stand, capable of moving in three mutually perpendicular directions. The nanovoltmeter and current source are interfaced with PC using RS232 serial interface. A software has been developed in for logging and processing of data. Proper optimization of measurement has been done through software to reduce the noise due to thermal emf and electromagnetic induction. The data acquired for some standard magnetic samples are presented. The sensitivity of the setup is 1microstrain with an error in measurement upto 5%.

Design and test of a simple fast electromagnetic inductive gas valve for planar pulsed inductive plasma thruster

NASA Astrophysics Data System (ADS)

Guo, Dawei; Cheng, Mousen; Li, Xiaokang

2017-10-01

In support of our planar pulsed inductive plasma thruster research, a fast electromagnetic inductive valve for a gas propellant injection system has been built and tested. A new and important design feature is the use of a conical diaphragm as the action part, which greatly contributes to the virtue of simplicity for adopting the resultant force of the diaphragm deformation as the closing force. An optical transmission technique is adopted to measure the opening and closing characters of the valve while the gas throughput is determined by measuring the pressure change per pulse in a test chamber with a capacitance manometer. The experimental results revealed that the delay time before the valve reaction is less than 40 μs, and the valve pulse width is no longer than 160 μs full width at half maximum. The valve delivers 0-2.5 mg of argon gas per pulse varied by adjusting the drive voltage and gas pressure.

Design and test of a simple fast electromagnetic inductive gas valve for planar pulsed inductive plasma thruster.

PubMed

Guo, Dawei; Cheng, Mousen; Li, Xiaokang

2017-10-01

In support of our planar pulsed inductive plasma thruster research, a fast electromagnetic inductive valve for a gas propellant injection system has been built and tested. A new and important design feature is the use of a conical diaphragm as the action part, which greatly contributes to the virtue of simplicity for adopting the resultant force of the diaphragm deformation as the closing force. An optical transmission technique is adopted to measure the opening and closing characters of the valve while the gas throughput is determined by measuring the pressure change per pulse in a test chamber with a capacitance manometer. The experimental results revealed that the delay time before the valve reaction is less than 40 μs, and the valve pulse width is no longer than 160 μs full width at half maximum. The valve delivers 0-2.5 mg of argon gas per pulse varied by adjusting the drive voltage and gas pressure.

Frequency domain electromagnetic induction survey in the intertidal zone: Limitations of low-induction-number and depth of exploration

NASA Astrophysics Data System (ADS)

Delefortrie, Samuël; Saey, Timothy; Van De Vijver, Ellen; De Smedt, Philippe; Missiaen, Tine; Demerre, Ine; Van Meirvenne, Marc

2014-01-01

Subsurface investigation in the Belgian intertidal zone is severely complicated due to high heterogeneity and tides. Near-surface geophysical techniques can offer assistance since they allow fast surveying and collection of high spatial density data and frequency domain electromagnetic induction (EMI) was chosen for archaeological prospection on the Belgian shore. However, in the intertidal zone the effects of extreme salinity compromise validity of low-induction-number (LIN) approximated EMI data. In this paper, the effects of incursion of seawater on multi-receiver EMI data are investigated by means of survey results, field observations, cone penetration tests and in-situ electrical conductivity measurements. The consequences of LIN approximation breakdown were researched. Reduced depth of investigation of the quadrature-phase (Qu) response and a complex interpretation of the in-phase response were confirmed. Nonetheless, a high signal-to-noise ratio of the Qu response and viable data with regard to shallow subsurface investigation were also evidenced, allowing subsurface investigation in the intertidal zone.

Apparent resistivity for transient electromagnetic induction logging and its correction in radial layer identification

NASA Astrophysics Data System (ADS)

Meng, Qingxin; Hu, Xiangyun; Pan, Heping; Xi, Yufei

2018-04-01

We propose an algorithm for calculating all-time apparent resistivity from transient electromagnetic induction logging. The algorithm is based on the whole-space transient electric field expression of the uniform model and Halley's optimisation. In trial calculations for uniform models, the all-time algorithm is shown to have high accuracy. We use the finite-difference time-domain method to simulate the transient electromagnetic field in radial two-layer models without wall rock and convert the simulation results to apparent resistivity using the all-time algorithm. The time-varying apparent resistivity reflects the radially layered geoelectrical structure of the models and the apparent resistivity of the earliest time channel follows the true resistivity of the inner layer; however, the apparent resistivity at larger times reflects the comprehensive electrical characteristics of the inner and outer layers. To accurately identify the outer layer resistivity based on the series relationship model of the layered resistance, the apparent resistivity and diffusion depth of the different time channels are approximately replaced by related model parameters; that is, we propose an apparent resistivity correction algorithm. By correcting the time-varying apparent resistivity of radial two-layer models, we show that the correction results reflect the radially layered electrical structure and the corrected resistivities of the larger time channels follow the outer layer resistivity. The transient electromagnetic fields of radially layered models with wall rock are simulated to obtain the 2D time-varying profiles of the apparent resistivity and corrections. The results suggest that the time-varying apparent resistivity and correction results reflect the vertical and radial geoelectrical structures. For models with small wall-rock effect, the correction removes the effect of the low-resistance inner layer on the apparent resistivity of the larger time channels.

An innovative experimental sequence on electromagnetic induction and eddy currents based on video analysis and cheap data acquisition

NASA Astrophysics Data System (ADS)

Bonanno, A.; Bozzo, G.; Sapia, P.

2017-11-01

In this work, we present a coherent sequence of experiments on electromagnetic (EM) induction and eddy currents, appropriate for university undergraduate students, based on a magnet falling through a drilled aluminum disk. The sequence, leveraging on the didactical interplay between the EM and mechanical aspects of the experiments, allows us to exploit the students’ awareness of mechanics to elicit their comprehension of EM phenomena. The proposed experiments feature two kinds of measurements: (i) kinematic measurements (performed by means of high-speed video analysis) give information on the system’s kinematics and, via appropriate numerical data processing, allow us to get dynamic information, in particular on energy dissipation; (ii) induced electromagnetic field (EMF) measurements (by using a homemade multi-coil sensor connected to a cheap data acquisition system) allow us to quantitatively determine the inductive effects of the moving magnet on its neighborhood. The comparison between experimental results and the predictions from an appropriate theoretical model (of the dissipative coupling between the moving magnet and the conducting disk) offers many educational hints on relevant topics related to EM induction, such as Maxwell’s displacement current, magnetic field flux variation, and the conceptual link between induced EMF and induced currents. Moreover, the didactical activity gives students the opportunity to be trained in video analysis, data acquisition and numerical data processing.

A Novel Shape Memory Plate Osteosynthesis for Noninvasive Modulation of Fixation Stiffness in a Rabbit Tibia Osteotomy Model

PubMed Central

Müller, Christian W.; Pfeifer, Ronny; Meier, Karen; Decker, Sebastian; Reifenrath, Janin; Gösling, Thomas; Wesling, Volker; Krettek, Christian; Krämer, Manuel

2015-01-01

Nickel-titanium shape memory alloy (NiTi-SMA) implants might allow modulating fracture healing, changing their stiffness through alteration of both elastic modulus and cross-sectional shape by employing the shape memory effect (SME). Hypotheses: a novel NiTi-SMA plate stabilizes tibia osteotomies in rabbits. After noninvasive electromagnetic induction heating the alloy exhibits the SME and the plate changes towards higher stiffness (inverse dynamization) resulting in increased fixation stiffness and equal or better bony healing. In 14 rabbits, 1.0 mm tibia osteotomies were fixed with our experimental plate. Animals were randomised for control or induction heating at three weeks postoperatively. Repetitive X-ray imaging and in vivo measurements of bending stiffness were performed. After sacrifice at 8 weeks, macroscopic evaluation, µCT, and post mortem bending tests of the tibiae were carried out. One death and one early implant dislocation occurred. Following electromagnetic induction heating, radiographic and macroscopic changes of the implant proved successful SME activation. All osteotomies healed. In the treatment group, bending stiffness increased over time. Differences between groups were not significant. In conclusion, we demonstrated successful healing of rabbit tibia osteotomies using our novel NiTi-SMA plate. We demonstrated shape-changing SME in-vivo through transcutaneous electromagnetic induction heating. Thus, future orthopaedic implants could be modified without additional surgery. PMID:26167493

Using a PC and external media to quantitatively investigate electromagnetic induction

NASA Astrophysics Data System (ADS)

Bonanno, A.; Bozzo, G.; Camarca, M.; Sapia, P.

2011-07-01

In this article we describe an experimental learning path about electromagnetic induction which uses an Atwood machine where one of the two hanging bodies is a cylindrical magnet falling through a plexiglass guide, surrounded either by a coil or by a copper pipe. The first configuration (magnet falling across a coil) allows students to quantitatively study the Faraday-Neumann-Lenz law, while the second configuration (falling through a copper pipe) permits learners to investigate the complex phenomena of induction by quantifying the amount of electric power dissipated through the pipe as a result of Foucault eddy currents, when the magnet travels through the pipe. The magnet's fall acceleration can be set by adjusting the counterweight of the Atwood machine so that both the kinematic quantities associated with it and the electromotive force induced within the coil are continuously and quantitatively monitored (respectively, by a common personal computer (PC) equipped with a webcam and by freely available software that makes it possible to use the audio card to convert the PC into an oscilloscope). Measurements carried out when the various experimental parameters are changed provide a useful framework for a thorough understanding and clarification of the conceptual nodes related to electromagnetic induction. The proposed learning path is under evaluation in various high schools participating in the project 'Lauree Scientifiche' promoted by the Italian Department of Education.

Calculation of electromagnetic force in electromagnetic forming process of metal sheet

NASA Astrophysics Data System (ADS)

Xu, Da; Liu, Xuesong; Fang, Kun; Fang, Hongyuan

2010-06-01

Electromagnetic forming (EMF) is a forming process that relies on the inductive electromagnetic force to deform metallic workpiece at high speed. Calculation of the electromagnetic force is essential to understand the EMF process. However, accurate calculation requires complex numerical solution, in which the coupling between the electromagnetic process and the deformation of workpiece needs be considered. In this paper, an appropriate formula has been developed to calculate the electromagnetic force in metal work-piece in the sheet EMF process. The effects of the geometric size of coil, the material properties, and the parameters of discharge circuit on electromagnetic force are taken into consideration. Through the formula, the electromagnetic force at different time and in different positions of the workpiece can be predicted. The calculated electromagnetic force and magnetic field are in good agreement with the numerical and experimental results. The accurate prediction of the electromagnetic force provides an insight into the physical process of the EMF and a powerful tool to design optimum EMF systems.

A Novel Angular Acceleration Sensor Based on the Electromagnetic Induction Principle and Investigation of Its Calibration Tests

PubMed Central

Zhao, Hao; Feng, Hao

2013-01-01

An angular acceleration sensor can be used for the dynamic analysis of human and joint motions. In this paper, an angular acceleration sensor with novel structure based on the principle of electromagnetic induction is designed. The method involves the construction of a constant magnetic field by the excitation windings of sensor, and the cup-shaped rotor that cut the magnetic field. The output windings of the sensor generate an electromotive force, which is directly proportional to the angular acceleration through the electromagnetic coupling when the rotor has rotational angular acceleration. The mechanical structure and the magnetic working circuit of the sensor are described. The output properties and the mathematical model including the transfer function and state-space model of the sensor are established. The asymptotical stability of the sensor when it is working is verified by the Lyapunov Theorem. An angular acceleration calibration device based on the torsional pendulum principle is designed. The method involves the coaxial connection of the angular acceleration sensor, torsion pendulum and a high-precision angle sensor, and then an initial external force is applied to the torsion pendulum to produce a periodic damping angle oscillation. The angular acceleration sensor and the angle sensor will generate two corresponding electrical signals. The sensitivity coefficient of the angular acceleration sensor can be obtained after processing these two-channel signals. The experiment results show that the sensitivity coefficient of the sensor is about 17.29 mv/Krad·s2. Finally, the errors existing in the practical applications of the sensor are discussed and the corresponding improvement measures are proposed to provide effective technical support for the practical promotion of the novel sensor. PMID:23941911

USSR Report, Electronics and Electrical Engineering, No. 104

DTIC Science & Technology

1983-06-13

shaping of silicon crystals during their growth is a modification of inductive contactless forming of rods and tubes directly from the melt on a...MANUFACTURING TECHNOLOGY Induction Systems for Electromagnetic Shaping of Silicon Crystal During.Growth (L. R. Lev; ELEKTROTEKHNIKA, Feb 83) • • • x...et al.; IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY: ELEKTROMEKHANIKA, Dec 82) 18 Basic Design of Linear- Induction Traction Motors for High-Speed

MR 201104: Evaluation of Discrimination Technologies and Classification Results and MR 201157: Demonstration of MetalMapper Static Data Acquisition and Data Analysis

DTIC Science & Technology

2016-09-23

Acquisition and Data Analysis). EMI sensors, MetalMapper, man-portable Time-domain Electromagnetic Multi-sensor Towed Array Detection System (TEMTADS...California Department of Toxic Substances Control EM61 EM61-MK2 EMI electromagnetic induction ESTCP Environmental Security Technology Certification...SOP Standard Operating Procedure v TEMTADS Time-domain Electromagnetic Multi-sensor Towed Array Detection System man-portable 2x2 TOI target(s

Electromagnetic induction imaging of concealed metallic objects by means of resonating circuits

NASA Astrophysics Data System (ADS)

Guilizzoni, R.; Watson, J. C.; Bartlett, P. A.; Renzoni, F.

2016-05-01

An electromagnetic induction system, suitable for 2D imaging of metallic samples of different electrical conductivities, has been developed. The system is based on a parallel LCR circuit comprising a ferrite-cored coil (7.8 mm x 9.5 mm, L=680 μH at 1 KHz), a variable resistor and capacitor. The working principle of the system is based on eddy current induction inside a metallic sample when this is introduced into the AC magnetic field created by the coil. The inductance of the LCR circuit is modified due to the presence of the sample, to an extent that depends on its conductivity. Such modification is known to increase when the system is operated at its resonant frequency. Characterizing different metals based on their values of conductivity is therefore possible by utilizing a suitable system operated at resonance. Both imaging and material characterization were demonstrated by means of the proposed electromagnetic induction technique. Furthermore, the choice of using a system with an adjustable resonant frequency made it possible to select resonances that allow magnetic-field penetration through conductive screens. Investigations on the possibility of imaging concealed metals by penetrating such shields have been carried out. A penetration depth of δ~3 mm through aluminium (Al) was achieved. This allowed concealed metallic samples- having conductivities ranging from 0.54 to 59.77 MSm-1 and hidden behind 1.5-mm-thick Al shields- to be imaged. Our results demonstrate that the presence of the concealed metallic objects can be revealed. The technique was thus shown to be a promising detection tool for security applications.

Electromagnetic deep-probing (100-1000 kms) of the Earth's interior from artificial satellites: Constraints on the regional emplacement of crustal resources

NASA Technical Reports Server (NTRS)

Hermance, J. F.

1983-01-01

The reconnaissance phase of using satellite observtions to studying electromagnetic induction in the solid earth is summarized. Several points are made: (1) satellite data apparently suffer far less from the effects of near surface lateral heterogeneities in the earth than do ground-based data; (2) zonal ionospheric currents during the recovery phase of major magnetic storms appear to be minimal, at least in the dawn and dusk sectors wher MAGSAT was flown; hence the internal contributions that satellites observe during these times is in fact due primarily to induction in the Earth with little or no contribution from ionospheric currents; and (3) the interpretation of satellite data in terms of primitive electromagnetic response functions, while grossly over-simplified, results in a surprisingly well-resolved radius for an equivalent super-conductor representing the conductivity region of the Earth's interior (5,370 + or - 120 km).

High-voltage pulse generator developed for wide-gap spark chambers

NASA Technical Reports Server (NTRS)

Keller, L. P.; Walschon, E. G.

1968-01-01

Low-inductance, high-capacitance Marx pulse generator provides for minimization of internal inductance and suppression of external electromagnetic radiation. The spark gaps of the generator are enclosed in a pressurized nitrogen atmosphere which allows the charging voltage to be varied by changing the nitrogen pressure.

Nuclear Electromagnetic Pulse Review

NASA Astrophysics Data System (ADS)

Dinallo, Michael

2011-04-01

Electromagnetic Pulse (EMP) from nuclear detonations have been observed for well over half a century. Beginning in the mid-to-late 1950s, the physics and modeling of EMP has been researched and will continue into the foreseeable future. The EMP environment propagates hundreds of miles from its origins and causes interference for all types of electronic instrumentation. This includes military, municipal and industry based electronic infrastructures such as power generation and distribution, command and control systems, systems used in financial and emergency services, electronic monitoring and communications networks, to mention some key infrastructure elements. Research into EMP has included originating physics, propagation and electromagnetic field coupling analyses and measurement-sensor development. Several methods for calculating EMP induced transient interference (voltage and current induction) will be briefly discussed and protection techniques reviewed. These methods can be mathematically simple or involve challenging boundary value solution techniques. A few illustrative calculations will demonstrate the concern for electronic system operability. Analyses such as the Wunsch-Bell model for electronic upset or damage, and the Singularity Expansion Method (SEM) put forth by Dr. Carl Baum, will facilitate the concern for EMP effects. The SEM determines the voltages and currents induced from transient electromagnetic fields in terms of natural modes of various types of electronic platforms (aerospace vehicles or land-based assets - fixed or mobile). Full-scale facility and laboratory simulation and response measurement approaches will be discussed. The talk will conclude with a discussion of some present research activities.

Pedemis: a portable electromagnetic induction sensor with integrated positioning

NASA Astrophysics Data System (ADS)

Barrowes, Benjamin E.; Shubitidze, Fridon; Grzegorczyk, Tomasz M.; Fernández, Pablo; O'Neill, Kevin

2012-06-01

Pedemis (PortablE Decoupled Electromagnetic Induction Sensor) is a time-domain handheld electromagnetic induction (EMI) instrument with the intended purpose of improving the detection and classification of UneXploded Ordnance (UXO). Pedemis sports nine coplanar transmitters (the Tx assembly) and nine triaxial receivers held in a fixed geometry with respect to each other (the Rx assembly) but with that Rx assembly physically decoupled from the Tx assembly allowing flexible data acquisition modes and deployment options. The data acquisition (DAQ) electronics consists of the National Instruments (NI) cRIO platform which is much lighter and more energy efficient that prior DAQ platforms. Pedemis has successfully acquired initial data, and inversion of the data acquired during these initial tests has yielded satisfactory polarizabilities of a spherical target. In addition, precise positioning of the Rx assembly has been achieved via position inversion algorithms based solely on the data acquired from the receivers during the "on-time" of the primary field. Pedemis has been designed to be a flexible yet user friendly EMI instrument that can survey, detect and classify targets in a one pass solution. In this paper, the Pedemis instrument is introduced along with its operation protocols, initial data results, and current status.

Research on Stabilization Properties of Inductive-Capacitive Transducers Based on Hybrid Electromagnetic Elements

NASA Astrophysics Data System (ADS)

Konesev, S. G.; Khazieva, R. T.; Kirllov, R. V.; Konev, A. A.

2017-01-01

Some electrical consumers (the charge system of storage capacitor, powerful pulse generators, electrothermal systems, gas-discharge lamps, electric ovens, plasma torches) require constant power consumption, while their resistance changes in the limited range. Current stabilization systems (CSS) with inductive-capacitive transducers (ICT) provide constant power, when the load resistance changes over a wide range and increaseы the efficiency of high-power loads’ power supplies. ICT elements are selected according to the maximum load, which leads to exceeding a predetermined value of capacity. The paper suggests carrying load power by the ICT based on multifunction integrated electromagnetic components (MIEC) to reduce the predetermined capacity of ICT elements and CSS weights and dimensions. The authors developed and patented ICT based on MIEC that reduces the CSS weights and dimensions by reducing components number with the possibility of device’s electric energy transformation and resonance frequency changing. An ICT mathematical model was produced. The model determines the width of the load stabilization range. Electromagnetic processes study model was built with the MIEC integral parameters (full inductance of the electrical lead, total capacity, current of electrical lead). It shows independence of the load current from the load resistance for different ways of MIEC connection.

Intracerebral hemorrhage (ICH) evaluation with a novel magnetic induction sensor: a preliminary study using the Chinese head model.

PubMed

Zhang, Ziyi; Liu, Peiguo; Zhou, Dongming; Zhang, Liang; Lei, Hengdong

2014-01-01

Biomedical magnetic induction measurement is a promising method for the detection of intracerebral hemorrhage (ICH), especially in China. Aiming at overcoming the problem of low sensitivity, a magnetic induction sensor is chosen to replace the conventional sensors. It uses a two-arm Archimedean spiral coil as the exciter and a circular coil as the receiver. In order to carry out high-fidelity simulations, the Chinese head model with real anatomical structure is introduced into this novel sensor for the first time. Simulations have been carried out upon early stage ICH measurements. By calculating the state sensitivity and time sensitivity of the perturbation phase of two types of sensors using the electromagnetic software, we conclude that the primary signal received can be largely reduced using the novel sensor, which could effectively increase the time and state sensitivity simultaneously.

Determination of efficiencies, loss mechanisms, and performance degradation factors in chopper controlled dc vehical motors. Section 2: The time dependent finite element modeling of the electromagnetic field in electrical machines: Methods and applications. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Hamilton, H. B.; Strangas, E.

1980-01-01

The time dependent solution of the magnetic field is introduced as a method for accounting for the variation, in time, of the machine parameters in predicting and analyzing the performance of the electrical machines. The method of time dependent finite element was used in combination with an also time dependent construction of a grid for the air gap region. The Maxwell stress tensor was used to calculate the airgap torque from the magnetic vector potential distribution. Incremental inductances were defined and calculated as functions of time, depending on eddy currents and saturation. The currents in all the machine circuits were calculated in the time domain based on these inductances, which were continuously updated. The method was applied to a chopper controlled DC series motor used for electric vehicle drive, and to a salient pole sychronous motor with damper bars. Simulation results were compared to experimentally obtained ones.

Regularized solution of a nonlinear problem in electromagnetic sounding

NASA Astrophysics Data System (ADS)

Piero Deidda, Gian; Fenu, Caterina; Rodriguez, Giuseppe

2014-12-01

Non destructive investigation of soil properties is crucial when trying to identify inhomogeneities in the ground or the presence of conductive substances. This kind of survey can be addressed with the aid of electromagnetic induction measurements taken with a ground conductivity meter. In this paper, starting from electromagnetic data collected by this device, we reconstruct the electrical conductivity of the soil with respect to depth, with the aid of a regularized damped Gauss-Newton method. We propose an inversion method based on the low-rank approximation of the Jacobian of the function to be inverted, for which we develop exact analytical formulae. The algorithm chooses a relaxation parameter in order to ensure the positivity of the solution and implements various methods for the automatic estimation of the regularization parameter. This leads to a fast and reliable algorithm, which is tested on numerical experiments both on synthetic data sets and on field data. The results show that the algorithm produces reasonable solutions in the case of synthetic data sets, even in the presence of a noise level consistent with real applications, and yields results that are compatible with those obtained by electrical resistivity tomography in the case of field data. Research supported in part by Regione Sardegna grant CRP2_686.

Application of induction heating in food processing and cooking: A Review

USDA-ARS?s Scientific Manuscript database

Induction heating is an electromagnetic heating technology that has several advantages such as high safety, scalability, and high energy efficiency. It has been applied for a long time in metal processing, medical applications, and cooking. However, the application of this technology in the food pro...

Demonstration of Lenz's Law with an Induction Motor

ERIC Educational Resources Information Center

Kraftmakher, Yaakov

2005-01-01

The interaction of a conductor with a time-dependent magnetic field is an important topic of electromagnetic theory. A computerized classroom demonstration shows how the eddy currents induced in the rotor of an induction motor cause its rotation or braking. Both phenomena are directly related to Lenz's law.

Demonstration of LenzÂ's law with an induction motor

NASA Astrophysics Data System (ADS)

Kraftmakher, Yaakov

2005-03-01

The interaction of a conductor with a time-dependent magnetic field is an important topic of electromagnetic theory. A computerized classroom demonstration shows how the eddy currents induced in the rotor of an induction motor cause its rotation or braking. Both phenomena are directly related to Lenz’s law.

Low-inductance bus lines

NASA Technical Reports Server (NTRS)

Kernick, A.

1977-01-01

Laminated bus strips and bifilar litz cable connectors for high-power rectifiers, thrisistors, and transistors provide low inductance and eliminate electromagnetic interference in high-power circuits. These techniques offer significant cost advantages because of ease of assembly and consistent high quality of product. Effectiveness makes general usage in static power conversion likely.

Future Directions of Electromagnetic Methods for Hydrocarbon Applications

NASA Astrophysics Data System (ADS)

Strack, K. M.

2014-01-01

For hydrocarbon applications, seismic exploration is the workhorse of the industry. Only in the borehole, electromagnetic (EM) methods play a dominant role, as they are mostly used to determine oil reserves and to distinguish water from oil-bearing zones. Throughout the past 60 years, we had several periods with an increased interest in EM. This increased with the success of the marine EM industry and now electromagnetics in general is considered for many new applications. The classic electromagnetic methods are borehole, onshore and offshore, and airborne EM methods. Airborne is covered elsewhere (see Smith, this issue). Marine EM material is readily available from the service company Web sites, and here I will only mention some future technical directions that are visible. The marine EM success is being carried back to the onshore market, fueled by geothermal and unconventional hydrocarbon applications. Oil companies are listening to pro-EM arguments, but still are hesitant to go through the learning exercises as early adopters. In particular, the huge business drivers of shale hydrocarbons and reservoir monitoring will bring markets many times bigger than the entire marine EM market. Additional applications include support for seismic operations, sub-salt, and sub-basalt, all areas where seismic exploration is costly and inefficient. Integration with EM will allow novel seismic methods to be applied. In the borehole, anisotropy measurements, now possible, form the missing link between surface measurements and ground truth. Three-dimensional (3D) induction measurements are readily available from several logging contractors. The trend to logging-while-drilling measurements will continue with many more EM technologies, and the effort of controlling the drill bit while drilling including look-ahead-and-around the drill bit is going on. Overall, the market for electromagnetics is increasing, and a demand for EM capable professionals will continue. The emphasis will be more on application and data integration (bottom-line value increase) and less on EM technology and modeling exercises.

Low Frequency Radio-wave System for subsurface investigation

NASA Astrophysics Data System (ADS)

Soldovieri, Francesco; Gennarelli, Gianluca; Kudelya, Anatoliy; Denisov, Alexander

2015-04-01

Low frequency radio-wave methods (RWM) allow subsurface investigations in terms of lithological structure characterization, detection of filtration flows of ground water, anthropogenic and natural cavities. In this contribution, we present a RWM that exploits two coils working at frequencies of few MHz as transmitting and receiving antennas. The basic principle of this inductive method is as follows. The primary alternating electromagnetic field radiated by the transmitting coil induces eddy currents in the subsurface mainly due to the conductivity anomalies. These eddy currents generate a secondary (scattered) magnetic field which overlaps to the incident magnetic field and is detected by the receiving coil. Despite the simple operation of the system, the complexity of the electromagnetic scattering phenomenon at hand must be properly modeled to achieve adequate performance. Therefore, an advanced data processing technique, belonging to the class of the inverse scattering approaches, has been developed by the authors in a full 3D geometry. The proposed method allows to deal with data collected on a scanning surface under a dipole inductive profiling (DIP) modality, where the transmitting/receiving coils are moved simultaneously with fixed offset (multi-bistatic configuration). The hardware, called Dipole Inductive Radio-wave System (DIRS), is composed by an electronic unit and transmitting and receiving loop antennas radiating at frequencies of few MHz (2-4 MHz), which are installed on theodolite supports. The compactness of DIRS and its robustness to external electromagnetic interference offers the possibility to perform geophysical research up to the depth of some tens of meters and under several types of ground and water surfaces, vegetation, and weather conditions. The light weight and small size of system (the single antenna with support weights about 5 kg and has a diameter of 0.5m) allows two operators to perform geophysical research without disturbing the surface integrity of investigated ground massif. The value of base and the value of voltage induced on the digital voltmeter of the receiver are stored in memory on a SD-card for a subsequent visualization and processing. Realistic cases of application of the DIRS system enhanced by the inverse scattering approach will be presented at the conference with regard to the geological characterization of a mine shaft and an archaeological site.

On coincident loop transient electromagnetic induction logging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swidinsky, Andrei; Weiss, Chester J.

Coincident loop transient induction wireline logging is examined as the borehole analog of the well-known land and airborne time-domain electromagnetic (EM) method. The concept of whole-space late-time apparent resistivity is modified from the half-space version commonly used in land and airborne geophysics and applied to the coincident loop voltages produced from various formation, borehole, and invasion models. Given typical tool diameters, off-time measurements with such an instrument must be made on the order of nanoseconds to microseconds — much more rapidly than for surface methods. Departure curves of the apparent resistivity for thin beds, calculated using an algorithm developed tomore » model the transient response of a loop in a multilayered earth, indicate that the depth of investigation scales with the bed thickness. Modeled resistivity logs are comparable in accuracy and resolution with standard frequency-domain focused induction logs. However, if measurement times are longer than a few microseconds, the thicknesses of conductors can be overestimated, whereas resistors are underestimated. Thin-bed resolution characteristics are explained by visualizing snapshots of the EM fields in the formation, where a conductor traps the electric field while two current maxima are produced in the shoulder beds surrounding a resistor. Radial profiling is studied using a concentric cylinder earth model. Results found that true formation resistivity can be determined in the presence of either oil- or water-based mud, although in the latter case, measurements must be taken several orders of magnitude later in time. Lastly, the ability to determine true formation resistivity is governed by the degree that the EM field heals after being distorted by borehole fluid and invasion, a process visualized and particularly evident in the case of conductive water-based mud.« less

On coincident loop transient electromagnetic induction logging

DOE PAGES

Swidinsky, Andrei; Weiss, Chester J.

2017-05-31

Coincident loop transient induction wireline logging is examined as the borehole analog of the well-known land and airborne time-domain electromagnetic (EM) method. The concept of whole-space late-time apparent resistivity is modified from the half-space version commonly used in land and airborne geophysics and applied to the coincident loop voltages produced from various formation, borehole, and invasion models. Given typical tool diameters, off-time measurements with such an instrument must be made on the order of nanoseconds to microseconds — much more rapidly than for surface methods. Departure curves of the apparent resistivity for thin beds, calculated using an algorithm developed tomore » model the transient response of a loop in a multilayered earth, indicate that the depth of investigation scales with the bed thickness. Modeled resistivity logs are comparable in accuracy and resolution with standard frequency-domain focused induction logs. However, if measurement times are longer than a few microseconds, the thicknesses of conductors can be overestimated, whereas resistors are underestimated. Thin-bed resolution characteristics are explained by visualizing snapshots of the EM fields in the formation, where a conductor traps the electric field while two current maxima are produced in the shoulder beds surrounding a resistor. Radial profiling is studied using a concentric cylinder earth model. Results found that true formation resistivity can be determined in the presence of either oil- or water-based mud, although in the latter case, measurements must be taken several orders of magnitude later in time. Lastly, the ability to determine true formation resistivity is governed by the degree that the EM field heals after being distorted by borehole fluid and invasion, a process visualized and particularly evident in the case of conductive water-based mud.« less

Analysis of non-equilibrium phenomena in inductively coupled plasma generators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, W.; Panesi, M., E-mail: mpanesi@illinois.edu; Lani, A.

This work addresses the modeling of non-equilibrium phenomena in inductively coupled plasma discharges. In the proposed computational model, the electromagnetic induction equation is solved together with the set of Navier-Stokes equations in order to compute the electromagnetic and flow fields, accounting for their mutual interaction. Semi-classical statistical thermodynamics is used to determine the plasma thermodynamic properties, while transport properties are obtained from kinetic principles, with the method of Chapman and Enskog. Particle ambipolar diffusive fluxes are found by solving the Stefan-Maxwell equations with a simple iterative method. Two physico-mathematical formulations are used to model the chemical reaction processes: (1) Amore » Local Thermodynamics Equilibrium (LTE) formulation and (2) a thermo-chemical non-equilibrium (TCNEQ) formulation. In the TCNEQ model, thermal non-equilibrium between the translational energy mode of the gas and the vibrational energy mode of individual molecules is accounted for. The electronic states of the chemical species are assumed in equilibrium with the vibrational temperature, whereas the rotational energy mode is assumed to be equilibrated with translation. Three different physical models are used to account for the coupling of chemistry and energy transfer processes. Numerical simulations obtained with the LTE and TCNEQ formulations are used to characterize the extent of non-equilibrium of the flow inside the Plasmatron facility at the von Karman Institute. Each model was tested using different kinetic mechanisms to assess the sensitivity of the results to variations in the reaction parameters. A comparison of temperatures and composition profiles at the outlet of the torch demonstrates that the flow is in non-equilibrium for operating conditions characterized by pressures below 30 000 Pa, frequency 0.37 MHz, input power 80 kW, and mass flow 8 g/s.« less

Analysis of non-equilibrium phenomena in inductively coupled plasma generators

NASA Astrophysics Data System (ADS)

Zhang, W.; Lani, A.; Panesi, M.

2016-07-01

This work addresses the modeling of non-equilibrium phenomena in inductively coupled plasma discharges. In the proposed computational model, the electromagnetic induction equation is solved together with the set of Navier-Stokes equations in order to compute the electromagnetic and flow fields, accounting for their mutual interaction. Semi-classical statistical thermodynamics is used to determine the plasma thermodynamic properties, while transport properties are obtained from kinetic principles, with the method of Chapman and Enskog. Particle ambipolar diffusive fluxes are found by solving the Stefan-Maxwell equations with a simple iterative method. Two physico-mathematical formulations are used to model the chemical reaction processes: (1) A Local Thermodynamics Equilibrium (LTE) formulation and (2) a thermo-chemical non-equilibrium (TCNEQ) formulation. In the TCNEQ model, thermal non-equilibrium between the translational energy mode of the gas and the vibrational energy mode of individual molecules is accounted for. The electronic states of the chemical species are assumed in equilibrium with the vibrational temperature, whereas the rotational energy mode is assumed to be equilibrated with translation. Three different physical models are used to account for the coupling of chemistry and energy transfer processes. Numerical simulations obtained with the LTE and TCNEQ formulations are used to characterize the extent of non-equilibrium of the flow inside the Plasmatron facility at the von Karman Institute. Each model was tested using different kinetic mechanisms to assess the sensitivity of the results to variations in the reaction parameters. A comparison of temperatures and composition profiles at the outlet of the torch demonstrates that the flow is in non-equilibrium for operating conditions characterized by pressures below 30 000 Pa, frequency 0.37 MHz, input power 80 kW, and mass flow 8 g/s.

AUTOMOTIVE DIESEL MAINTENANCE 2. UNIT XI, INTRODUCTION TO ELECTRICAL MAINTENANCE FOR OFF-HIGHWAY VEHICLES.

ERIC Educational Resources Information Center

Human Engineering Inst., Cleveland, OH.

THIS MODULE OF A 25-MODULE COURSE IS DESIGNED TO FAMILIARIZE THE TRAINEE WITH THE FUNDAMENTALS OF ELECTRICITY AND MAGNETISM AS THEY RELATE TO DIESEL POWERED EQUIPMENT. TOPICS ARE (1) FUNDAMENTALS OF ELECTRICITY AND MAGNETISM, (2) ELECTROMAGNETIC FIELDS, (3) MAGNETIC FORCE ON A CONDUCTOR, (4) ELECTROMAGNETIC INDUCTION, (5) OHM'S LAW, (6) METER…

A Novel Tactile Sensor with Electromagnetic Induction and Its Application on Stick-Slip Interaction Detection

PubMed Central

Liu, Yanjie; Han, Haijun; Liu, Tao; Yi, Jingang; Li, Qingguo; Inoue, Yoshio

2016-01-01

Real-time detection of contact states, such as stick-slip interaction between a robot and an object on its end effector, is crucial for the robot to grasp and manipulate the object steadily. This paper presents a novel tactile sensor based on electromagnetic induction and its application on stick-slip interaction. An equivalent cantilever-beam model of the tactile sensor was built and capable of constructing the relationship between the sensor output and the friction applied on the sensor. With the tactile sensor, a new method to detect stick-slip interaction on the contact surface between the object and the sensor is proposed based on the characteristics of friction change. Furthermore, a prototype was developed for a typical application, stable wafer transferring on a wafer transfer robot, by considering the spatial magnetic field distribution and the sensor size according to the requirements of wafer transfer. The experimental results validate the sensing mechanism of the tactile sensor and verify its feasibility of detecting stick-slip on the contact surface between the wafer and the sensor. The sensing mechanism also provides a new approach to detect the contact state on the soft-rigid surface in other robot-environment interaction systems. PMID:27023545

Electromagnetic Induction Spectroscopy for the Detection of Subsurface Targets

DTIC Science & Technology

2012-12-01

curves of the proposed method and that of Fails et al.. For the kNN ROC curve, k = 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81...et al. [6] and Ramachandran et al. [7] both demonstrated success in detecting mines using the k-nearest-neighbor ( kNN ) algorithm based on the EMI...error is also included in the feature vector. The kNN labels an unknown target based on the closest targets in a training set. Collins et al. [2] and

Electromagnetic geophysical observation with controlled source

NASA Astrophysics Data System (ADS)

Hachay, Olga; Khachay, Oleg

2016-04-01

In the paper the new theoretical and methodical approaches are examined for detailed investigations of the structure and state of the geological medium, and its behavior as a dynamic system in reaction to external man-made influences. To solve this problem it is necessary to use geophysical methods that have sufficient resolution and that are built on more complicated models than layered or layered-block models. One of these methods is the electromagnetic induction frequency-geometrical method with controlled sources. Here we consider new approaches using this method for monitoring rock shock media by means of natural experiments and interpretation of the practical results. That method can be used by oil production in mines, where the same events of non stability can occur. The key ideas of twenty first century geophysics from the point of view of geologist academician A.N. Dmitrievskiy [Dmitrievskiy, 2009] are as follows. "The geophysics of the twenty first century is an understanding that the Earth is a self-developing, self-supporting geo-cybernetic system, in which the role of the driving mechanism is played by the field gradients; the evolution of geological processes is a continuous chain of transformations and the interaction of geophysical fields in the litho- hydro- and atmosphere. The use of geophysical principles of a hierarchical quantum of geophysical space, non-linear effects, and the effects of reradiating geophysical fields will allow the creation of a new geophysics. The research, in which earlier only pure geophysical processes and technologies were considered, nowadays tends to include into consideration geophysical-chemical processes and technologies. This transformation will allow us to solve the problems of forecasting geo-objects and geo-processes in previously unavailable geological-technological conditions." The results obtained allow us to make the following conclusions, according to the key ideas of academician A.N. Dmitrievskiy: the rock massif is a multi-ranked hierarchical structure. Research of the massif state dynamics, its structure and the effects of self-organization in it can be provided by geophysical methods, which are built upon the model of such medium. The use of the planshet multi-level induction electromagnetic method with a controlled source of excitation and a corresponding method of processing and interpretation has allowed us to reveal the disintegration zones which are indicators of massif stability and understand the causes of low productivity of oil recovery from boreholes.

Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers

DOEpatents

Danby, G.T.; Jackson, J.W.

1990-03-19

A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations (dB/dt) in the particle beam.

Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers

DOEpatents

Danby, Gordon T.; Jackson, John W.

1991-01-01

A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations in the particle beam.

Electromagnetic Compatibility of Devices on Hybrid Electromagnetic Components

NASA Astrophysics Data System (ADS)

Konesev, S. G.; Khazieva, R. T.; Kirillov, R. V.; Gainutdinov, I. Z.; Kondratyev, E. Y.

2018-01-01

There is a general tendency to reduce the weight and dimensions, the consumption of conductive and electrical insulating materials, increase the reliability and energy efficiency of electrical devices. In recent years, designers have been actively developing devices based on hybrid electromagnetic components (HEMC) such as inductive-capacitive converters (ICC), voltages pulse generators (VPG), secondary power supplies (SPS), capacitive storage devices (CSD), induction heating systems (IHS). Sources of power supplies of similar electrical devices contain, as a rule, links of increased frequency and function in key (pulse) modes, which leads to an increase in electromagnetic interference (EMI). Nonlinear and periodic (impulse) loads, non-sinusoidal (pulsation) of the electromotive force and nonlinearity of the internal parameters of the source and input circuits of consumers distort the shape of the input voltage lead to an increase in thermal losses from the higher harmonic currents, aging of the insulation, increase in the weight of the power supply filter units, resonance at higher harmonics. The most important task is to analyze the operation of electrotechnical devices based on HEMC from the point of view of creating EMIs and assessing their electromagnetic compatibility (EMC) with power supply systems (PSS). The article presents the results of research on the operation of an IHS, the operation principle of a secondary power supply source of which is based on the operation of a half-bridge autonomous inverter, the switching circuit of which is made in the form of a HEMC, called the «multifunctional integrated electromagnetic component»" (MIEC).

Comparing the magnetic resonant coupling radiofrequency stimulation to the traditional approaches: Ex-vivo tissue voltage measurement and electromagnetic simulation analysis

NASA Astrophysics Data System (ADS)

Yeung, Sai Ho; Pradhan, Raunaq; Feng, Xiaohua; Zheng, Yuanjin

2015-09-01

Recently, the design concept of magnetic resonant coupling has been adapted to electromagnetic therapy applications such as non-invasive radiofrequency (RF) stimulation. This technique can significantly increase the electric field radiated from the magnetic coil at the stimulation target, and hence enhancing the current flowing through the nerve, thus enabling stimulation. In this paper, the developed magnetic resonant coupling (MRC) stimulation, magnetic stimulation (MS) and transcutaneous electrical nerve stimulation (TENS) are compared. The differences between the MRC RF stimulation and other techniques are presented in terms of the operating mechanism, ex-vivo tissue voltage measurement and electromagnetic simulation analysis. The ev-vivo tissue voltage measurement experiment is performed on the compared devices based on measuring the voltage induced by electromagnetic induction at the tissue. The focusing effect, E field and voltage induced across the tissue, and the attenuation due to the increase of separation between the coil and the target are analyzed. The electromagnetic stimulation will also be performed to obtain the electric field and magnetic field distribution around the biological medium. The electric field intensity is proportional to the induced current and the magnetic field is corresponding to the electromagnetic induction across the biological medium. The comparison between the MRC RF stimulator and the MS and TENS devices revealed that the MRC RF stimulator has several advantages over the others for the applications of inducing current in the biological medium for stimulation purposes.

Comparing the magnetic resonant coupling radiofrequency stimulation to the traditional approaches: Ex-vivo tissue voltage measurement and electromagnetic simulation analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yeung, Sai Ho; Pradhan, Raunaq; Feng, Xiaohua

Recently, the design concept of magnetic resonant coupling has been adapted to electromagnetic therapy applications such as non-invasive radiofrequency (RF) stimulation. This technique can significantly increase the electric field radiated from the magnetic coil at the stimulation target, and hence enhancing the current flowing through the nerve, thus enabling stimulation. In this paper, the developed magnetic resonant coupling (MRC) stimulation, magnetic stimulation (MS) and transcutaneous electrical nerve stimulation (TENS) are compared. The differences between the MRC RF stimulation and other techniques are presented in terms of the operating mechanism, ex-vivo tissue voltage measurement and electromagnetic simulation analysis. The ev-vivo tissuemore » voltage measurement experiment is performed on the compared devices based on measuring the voltage induced by electromagnetic induction at the tissue. The focusing effect, E field and voltage induced across the tissue, and the attenuation due to the increase of separation between the coil and the target are analyzed. The electromagnetic stimulation will also be performed to obtain the electric field and magnetic field distribution around the biological medium. The electric field intensity is proportional to the induced current and the magnetic field is corresponding to the electromagnetic induction across the biological medium. The comparison between the MRC RF stimulator and the MS and TENS devices revealed that the MRC RF stimulator has several advantages over the others for the applications of inducing current in the biological medium for stimulation purposes.« less

Emergent spin electromagnetism induced by magnetization textures in the presence of spin-orbit interaction (invited)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tatara, Gen, E-mail: gen.tatara@riken.jp; Nakabayashi, Noriyuki; Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397 Japan

2014-05-07

Emergent electromagnetic field which couples to electron's spin in ferromagnetic metals is theoretically studied. Rashba spin-orbit interaction induces spin electromagnetic field which is in the linear order in gradient of magnetization texture. The Rashba-induced effective electric and magnetic fields satisfy in the absence of spin relaxation the Maxwell's equations as in the charge-based electromagnetism. When spin relaxation is taken into account besides spin dynamics, a monopole current emerges generating spin motive force via the Faraday's induction law. The monopole is expected to play an important role in spin-charge conversion and in the integration of spintronics into electronics.

The Safety of Aircraft Exposed to Electromagnetic Fields: HIRF Testing of Aircraft Using Direct Current Injection

DTIC Science & Technology

2007-06-01

massive RF power to the antenna feed points without providing an inductive path to earth. Given all the above challenges, and especially the... circuit theory currents are flowing limited by the three parallel 50 ohm resistances and low inductive reactance. This plateaus at eigencurrent...relative to nett TEM cell input power has been calculated: Figure 86 Expected power output from probe, neglecting probe inductance DSTO-RR-0329

iSOIL: Interactions between soil related sciences - Linking geophysics, soil science and digital soil mapping

NASA Astrophysics Data System (ADS)

Dietrich, Peter; Werban, Ulrike; Sauer, Uta

2010-05-01

High-resolution soil property maps are one major prerequisite for the specific protection of soil functions and restoration of degraded soils as well as sustainable land use, water and environmental management. To generate such maps the combination of digital soil mapping approaches and remote as well as proximal soil sensing techniques is most promising. However, a feasible and reliable combination of these technologies for the investigation of large areas (e.g. catchments and landscapes) and the assessment of soil degradation threats is missing. Furthermore, there is insufficient dissemination of knowledge on digital soil mapping and proximal soil sensing in the scientific community, to relevant authorities as well as prospective users. As one consequence there is inadequate standardization of techniques. At the poster we present the EU collaborative project iSOIL within the 7th framework program of the European Commission. iSOIL focuses on improving fast and reliable mapping methods of soil properties, soil functions and soil degradation risks. This requires the improvement and integration of advanced soil sampling approaches, geophysical and spectroscopic measuring techniques, as well as pedometric and pedophysical approaches. The focus of the iSOIL project is to develop new and to improve existing strategies and innovative methods for generating accurate, high resolution soil property maps. At the same time the developments will reduce costs compared to traditional soil mapping. ISOIL tackles the challenges by the integration of three major components: (i)high resolution, non-destructive geophysical (e.g. Electromagnetic Induction EMI; Ground Penetrating Radar, GPR; magnetics, seismics) and spectroscopic (e.g., Near Surface Infrared, NIR) methods, (ii)Concepts of Digital Soil Mapping (DSM) and pedometrics as well as (iii)optimized soil sampling with respect to profound soil scientific and (geo)statistical strategies. A special focus of iSOIL lies on the sustainable dissemination of technologies and concepts developed in the projects through workshops for stakeholders and the publication of a handbook "Methods and Technologies for Mapping of Soil Properties, Function and Threat Risks". Besides, the CEN Workshop offers a new mechanism and approach to standardization. During the project we decided that the topic of the CEN Workshop should focus on a voluntary standardization of electromagnetic induction measurement to ensure that results can be evaluated and processed under uniform circumstances and can be comparable. At the poster we will also present the idea and the objectives of our CEN Workshop "Best Practice Approach for electromagnetic induction measurements of the near surface"and invite every interested person to participate.

Measurement and control systems for an imaging electromagnetic flow metre.

PubMed

Zhao, Y Y; Lucas, G; Leeungculsatien, T

2014-03-01

Electromagnetic flow metres based on the principles of Faraday's laws of induction have been used successfully in many industries. The conventional electromagnetic flow metre can measure the mean liquid velocity in axisymmetric single phase flows. However, in order to achieve velocity profile measurements in single phase flows with non-uniform velocity profiles, a novel imaging electromagnetic flow metre (IEF) has been developed which is described in this paper. The novel electromagnetic flow metre which is based on the 'weight value' theory to reconstruct velocity profiles is interfaced with a 'Microrobotics VM1' microcontroller as a stand-alone unit. The work undertaken in the paper demonstrates that an imaging electromagnetic flow metre for liquid velocity profile measurement is an instrument that is highly suited for control via a microcontroller. © 2013 ISA Published by ISA All rights reserved.

Neodymium Magnets.

ERIC Educational Resources Information Center

Wida, Sam

1992-01-01

Uses extremely strong neodymium magnets to demonstrate several principles of physics including electromagnetic induction, Lenz's Law, domain theory, demagnetization, the Curie point, and magnetic flux lines. (MDH)

Influence of winding construction on starter-generator thermal processes

NASA Astrophysics Data System (ADS)

Grachev, P. Yu; Bazarov, A. A.; Tabachinskiy, A. S.

2018-01-01

Dynamic processes in starter-generators features high winding are overcurrent. It can lead to insulation overheating and fault operation mode. For hybrid and electric vehicles, new high efficiency construction of induction machines windings is proposed. Stator thermal processes need be considered in the most difficult operation modes. The article describes construction features of new compact stator windings, electromagnetic and thermal models of processes in stator windings and explains the influence of innovative construction on thermal processes. Models are based on finite element method.

A solid-state controllable power supply for a magnetic suspension wind tunnel

NASA Technical Reports Server (NTRS)

Daniels, Taumi S.; Tripp, John S.

1991-01-01

The NASA Langley 6-inch Magnetic Suspension and Balance System (6-in. MSBS) requires an independently controlled bidirectional dc power source for each of six positioning electromagnets. These electromagnets provide five-degree-of-freedom control over a suspended aerodynamic test model. Existing power equipment, which employs resistance-coupled thyratron-controlled rectifiers as well as ac to dc motor-generator converters, is obsolete, inefficient, and unreliable. A replacement six-phase bidirectional controlled bridge rectifier is proposed, which employs power MOSFET switches sequenced by hybrid analog/digital circuits. Full-load efficiency is 80 percent compared with 25 percent for the resistance-coupled thyratron system. Current feedback provides high control linearity, adjustable current limiting, and current overload protection. A quenching circuit suppresses inductive voltage impulses. It is shown that 20-kHz interference from positioning magnet power into MSBS electromagnetic model position sensors results predominantly from capacitively coupled electric fields. Hence, proper shielding and grounding techniques are necessary. Inductively coupled magnetic interference is negligible.

Global simulation of the induction heating TSSG process of SiC for the effects of Marangoni convection, free surface deformation and seed rotation

NASA Astrophysics Data System (ADS)

Yamamoto, Takuya; Okano, Yasunori; Ujihara, Toru; Dost, Sadik

2017-07-01

A global numerical simulation was performed for the induction heating Top-Seeded Solution Growth (TSSG) process of SiC. Analysis included the furnace and growth melt. The effects of interfacial force due to free surface tension gradient, the RF coil-induced electromagnetic body force, buoyancy, melt free surface deformation, and seed rotation were examined. The simulation results showed that the contributions of free surface tension gradient and the electromagnetic body force to the melt flow are significant. Marangoni convection affects the growth process adversely by making the melt flow downward in the region under the seed crystal. This downward flow reduces carbon flux into the seed and consequently lowers growth rate. The effects of free surface deformation and seed rotation, although positive, are not so significant compared with those of free surface tension gradient and the electromagnetic body force. Due to the small size of the melt the contribution of buoyancy is also small.

A Theoretical Model to Predict Both Horizontal Displacement and Vertical Displacement for Electromagnetic Induction-Based Deep Displacement Sensors

PubMed Central

Shentu, Nanying; Zhang, Hongjian; Li, Qing; Zhou, Hongliang; Tong, Renyuan; Li, Xiong

2012-01-01

Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type) to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA) to describe its sensing characters. However in many landslide and related geological engineering cases, both horizontal displacement and vertical displacement vary apparently and dynamically so both may require monitoring. In this study, a II-type deep displacement sensor is designed by revising our I-type sensor to simultaneously monitor the deep horizontal displacement and vertical displacement variations at different depths within a sliding mass. Meanwhile, a new theoretical modeling called the numerical integration-based equivalent loop approach (NIELA) has been proposed to quantitatively depict II-type sensors’ mutual inductance properties with respect to predicted horizontal displacements and vertical displacements. After detailed examinations and comparative studies between measured mutual inductance voltage, NIELA-based mutual inductance and EELA-based mutual inductance, NIELA has verified to be an effective and quite accurate analytic model for characterization of II-type sensors. The NIELA model is widely applicable for II-type sensors’ monitoring on all kinds of landslides and other related geohazards with satisfactory estimation accuracy and calculation efficiency. PMID:22368467

A theoretical model to predict both horizontal displacement and vertical displacement for electromagnetic induction-based deep displacement sensors.

PubMed

Shentu, Nanying; Zhang, Hongjian; Li, Qing; Zhou, Hongliang; Tong, Renyuan; Li, Xiong

2012-01-01

Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type) to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA) to describe its sensing characters. However in many landslide and related geological engineering cases, both horizontal displacement and vertical displacement vary apparently and dynamically so both may require monitoring. In this study, a II-type deep displacement sensor is designed by revising our I-type sensor to simultaneously monitor the deep horizontal displacement and vertical displacement variations at different depths within a sliding mass. Meanwhile, a new theoretical modeling called the numerical integration-based equivalent loop approach (NIELA) has been proposed to quantitatively depict II-type sensors' mutual inductance properties with respect to predicted horizontal displacements and vertical displacements. After detailed examinations and comparative studies between measured mutual inductance voltage, NIELA-based mutual inductance and EELA-based mutual inductance, NIELA has verified to be an effective and quite accurate analytic model for characterization of II-type sensors. The NIELA model is widely applicable for II-type sensors' monitoring on all kinds of landslides and other related geohazards with satisfactory estimation accuracy and calculation efficiency.

Electromagnetic pulsed thermography for natural cracks inspection

NASA Astrophysics Data System (ADS)

Gao, Yunlai; Tian, Gui Yun; Wang, Ping; Wang, Haitao; Gao, Bin; Woo, Wai Lok; Li, Kongjing

2017-02-01

Emerging integrated sensing and monitoring of material degradation and cracks are increasingly required for characterizing the structural integrity and safety of infrastructure. However, most conventional nondestructive evaluation (NDE) methods are based on single modality sensing which is not adequate to evaluate structural integrity and natural cracks. This paper proposed electromagnetic pulsed thermography for fast and comprehensive defect characterization. It hybrids multiple physical phenomena i.e. magnetic flux leakage, induced eddy current and induction heating linking to physics as well as signal processing algorithms to provide abundant information of material properties and defects. New features are proposed using 1st derivation that reflects multiphysics spatial and temporal behaviors to enhance the detection of cracks with different orientations. Promising results that robust to lift-off changes and invariant features for artificial and natural cracks detection have been demonstrated that the proposed method significantly improves defect detectability. It opens up multiphysics sensing and integrated NDE with potential impact for natural understanding and better quantitative evaluation of natural cracks including stress corrosion crack (SCC) and rolling contact fatigue (RCF).

Non-contact electromagnetic induction heating for eradicating bacteria and yeasts on biomaterials and possible relevance to orthopaedic implant infections: In vitro findings.

PubMed

Pijls, B G; Sanders, I M J G; Kuijper, E J; Nelissen, R G H H

2017-05-01

Infection of implants is a major problem in elective and trauma surgery. Heating is an effective way to reduce the bacterial load in food preparation, and studies on hyperthermia treatment for cancer have shown that it is possible to heat metal objects with pulsed electromagnetic fields selectively (PEMF), also known as induction heating. We therefore set out to answer the following research question: is non-contact induction heating of metallic implants effective in reducing bacterial load in vitro ? Titanium alloy cylinders (Ti6Al4V) were exposed to PEMF from an induction heater with maximum 2000 watts at 27 kHz after being contaminated with five different types of micro-organisms: Staphylococcus epidermidis; Staphylococcus aureus; Pseudomonas aeruginosa ; spore-forming Bacillus cereus; and yeast Candida albicans . The cylinders were exposed to incremental target temperatures (35°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C) for up to 3.5 minutes. There was an average linear heating rate of 0.39°C per second up to the target temperature, and thereafter the target temperature was maintained until the end of the experiment. At 60°C and higher (duration 3.5 minutes), there was a 6-log reduction or higher for every micro-organism tested. At 60°C, we found that the shortest duration of effective induction heating was 1.5 minutes. This resulted in a 5-log reduction or higher for every micro-organism tested. Non-contact induction heating of a titanium disk is effective in reducing bacterial load in vitro . These promising results can be further explored as a new treatment modality for infections of metal orthopaedic implants. Cite this article : B. G. Pijls, I. M. J. G. Sanders, E. J. Kuijper, R. G. H. H. Nelissen. Non-contact electromagnetic induction heating for eradicating bacteria and yeasts on biomaterials and possible relevance to orthopaedic implant infections: In vitro findings. Bone Joint Res 2017;6:323-330. DOI: 10.1302/2046-3758.65.BJR-2016-0308.R1. © 2017 Pijls et al.

Overview of Advanced Electromagnetic Propulsion Development at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Pencil, Eric J.; Kamhawi, Hani; Gilland, James H.; Arrington, Lynn A.

2005-01-01

NASA Glenn Research Center s Very High Power Electric Propulsion task is sponsored by the Energetics Heritage Project. Electric propulsion technologies currently being investigated under this program include pulsed electromagnetic plasma thrusters, magnetoplasmadynamic thrusters, helicon plasma sources as well as the systems models for high power electromagnetic propulsion devices. An investigation and evaluation of pulsed electromagnetic plasma thruster performance at energy levels up to 700 Joules is underway. On-going magnetoplasmadynamic thruster experiments will investigate applied-field performance characteristics of gas-fed MPDs. Plasma characterization of helicon plasma sources will provide additional insights into the operation of this novel propulsion concept. Systems models have been developed for high power electromagnetic propulsion concepts, such as pulsed inductive thrusters and magnetoplasmadynamic thrusters to enable an evaluation of mission-optimized designs.

Comparative study of two commercially pure titanium casting methods

PubMed Central

RODRIGUES, Renata Cristina Silveira; FARIA, Adriana Claudia Lapria; ORSI, Iara Augusta; de MATTOS, Maria da Gloria Chiarello; MACEDO, Ana Paula; RIBEIRO, Ricardo Faria

2010-01-01

The interest in using titanium to fabricate removable partial denture (RPD) frameworks has increased, but there are few studies evaluating the effects of casting methods on clasp behavior. Objective This study compared the occurrence of porosities and the retentive force of commercially pure titanium (CP Ti) and cobalt-chromium (Co-Cr) removable partial denture circumferential clasps cast by induction/centrifugation and plasma/vacuum-pressure. Material and Methods 72 frameworks were cast from CP Ti (n=36) and Co-Cr alloy (n=36; control group). For each material, 18 frameworks were casted by electromagnetic induction and injected by centrifugation, whereas the other 18 were casted by plasma and injected by vacuum-pressure. For each casting method, three subgroups (n=6) were formed: 0.25 mm, 0.50 mm, and 0.75 mm undercuts. The specimens were radiographed and subjected to an insertion/removal test simulating 5 years of framework use. Data were analyzed by ANOVA and Tukey's to compare materials and cast methods (α=0.05). Results Three of 18 specimens of the induction/centrifugation group and 9 of 18 specimens of plasma/vacuum-pressure cast presented porosities, but only 1 and 7 specimens, respectively, were rejected for simulation test. For Co-Cr alloy, no defects were found. Comparing the casting methods, statistically significant differences (p<0.05) were observed only for the Co-Cr alloy with 0.25 mm and 0.50 mm undercuts. Significant differences were found for the 0.25 mm and 0.75 mm undercuts dependent on the material used. For the 0.50 mm undercut, significant differences were found when the materials were induction casted. Conclusion Although both casting methods produced satisfactory CP Ti RPD frameworks, the occurrence of porosities was greater in the plasma/vacuum-pressure than in the induction/centrifugation method, the latter resulting in higher clasp rigidity, generating higher retention force values. PMID:21085805

Genotoxic effects of exposure to radiofrequency electromagnetic fields (RF-EMF) in HL-60 cells are not reproducible.

PubMed

Speit, Günter; Gminski, Richard; Tauber, Rudolf

2013-08-15

Conflicting results have been published regarding the induction of genotoxic effects by exposure to radiofrequency electromagnetic fields (RF-EMF). Various results indicating a genotoxic potential of RF-EMF were reported by the collaborative EU-funded REFLEX (Risk Evaluation of Potential Environmental Hazards From Low Energy Electromagnetic Field Exposure Using Sensitive in vitro Methods) project. There has been a long-lasting scientific debate about the reliability of the reported results and an attempt to reproduce parts of the results obtained with human fibroblasts failed. Another part of the REFLEX study was performed in Berlin with the human lymphoblastoid cell line HL-60; genotoxic effects of RF-EMF were measured by means of the comet assay and the micronucleus test. The plausibility and reliability of these results were also questioned. In order to contribute to a clarification of the biological significance of the reported findings, a repeat study was performed, involving scientists of the original study. Comet-assay experiments and micronucleus tests were performed under the same experimental conditions that had led to genotoxic effects in the REFLEX study. Here we report that the attempts to reproduce the induction of genotoxic effects by RF-EMF in HL-60 cells failed. No genotoxic effects of RF-EMF were measured in the repeat experiments. We could not find an explanation for the conflicting results. However, the negative repeat experiments suggest that the biological significance of genotoxic effects of RF-EMF reported by the REFLEX study should be re-assessed. Copyright © 2013 Elsevier B.V. All rights reserved.

Theory of topological insulator waveguides: polarization control and the enhancement of the magneto-electric effect

NASA Astrophysics Data System (ADS)

Crosse, J. A.

2017-02-01

Topological insulators subject to a time-reversal-symmetry-breaking perturbation are predicted to display a magneto-electric effect that causes the electric and magnetic induction fields to mix at the material’s surface. This effect induces polarization rotations of between ≈1-10 mrad per interface in an incident plane-polarized electromagnetic wave normal to a multilayered structure. Here we show, theoretically and numerically, that by using a waveguide geometry with a topological insulator guide layer and magneto-dielectric cladding it is possible to achieve rotations of ≈100 mrad and generate an elliptical polarization with only a three-layered structure. This geometry is beneficial, not only as a way to enhance the magneto-electric effect, rendering it easier to observe, but also as a method for controlling the polarization of electromagnetic radiation.

A multiphysics and multiscale model for low frequency electromagnetic direct-chill casting

NASA Astrophysics Data System (ADS)

Košnik, N.; Guštin, A. Z.; Mavrič, B.; Šarler, B.

2016-03-01

Simulation and control of macrosegregation, deformation and grain size in low frequency electromagnetic (EM) direct-chill casting (LFEMC) is important for downstream processing. Respectively, a multiphysics and multiscale model is developed for solution of Lorentz force, temperature, velocity, concentration, deformation and grain structure of LFEMC processed aluminum alloys, with focus on axisymmetric billets. The mixture equations with lever rule, linearized phase diagram, and stationary thermoelastic solid phase are assumed, together with EM induction equation for the field imposed by the coil. Explicit diffuse approximate meshless solution procedure [1] is used for solving the EM field, and the explicit local radial basis function collocation method [2] is used for solving the coupled transport phenomena and thermomechanics fields. Pressure-velocity coupling is performed by the fractional step method [3]. The point automata method with modified KGT model is used to estimate the grain structure [4] in a post-processing mode. Thermal, mechanical, EM and grain structure outcomes of the model are demonstrated. A systematic study of the complicated influences of the process parameters can be investigated by the model, including intensity and frequency of the electromagnetic field. The meshless solution framework, with the implemented simplest physical models, will be further extended by including more sophisticated microsegregation and grain structure models, as well as a more realistic solid and solid-liquid phase rheology.

Autonomous Sea-Ice Thickness Survey

DTIC Science & Technology

2016-06-01

to tow an electromagnetic induction meter over sea ice in McMurdo Sound, Antarctica. This proof-of-concept survey aimed to demonstrate improved...EM31 electromagnetic ice-thickness meter along the Pegasus Cut- Off Road near McMurdo Station, Antarctic, on 11 November 2014...supported the GPS antenna (white disk). The orange 200 MHz antenna and smaller 400 MHz antenna (not visible) mounted in front of the black case. The

ALLTEM Multi-Axis Electromagnetic Induction System Demonstration and Validation

DTIC Science & Technology

2012-08-01

threshold T-high higher threshold TMGS Tensor Magnetic Gradiometer System TOI target of interest Tx ALLTEM transmitter USGS U.S. Geological...the Tensor Magnetic Gradiometer System ( TMGS ) and two prototype EMI instruments, the Very Early Time-domain ElectroMagnetic (VETEM) system and the...project one prototype magnetic system, the TMGS , and two prototype EMI instruments, VETEM and the High Frequency Sounder, were evaluated. Subsequent

Velocity damper for electromagnetically levitated materials

DOEpatents

Fox, Richard J.

1994-01-01

A system for damping oscillatory and spinning motions induced in an electromagnetically levitated material. Two opposed field magnets are located orthogonally to the existing levitation coils for providing a DC quadrupole field (cusp field) around the material. The material used for generating the DC quadrupole field must be nonconducting to avoid eddy-current heating and of low magnetic permeability to avoid distorting the induction fields providing the levitation.

[Pulse-modulated Electromagnetic Radiation of Extremely High Frequencies Protects Cellular DNA against Damaging Effect of Physico-Chemical Factors in vitro].

PubMed

Gapeyev, A B; Lukyanova, N A

2015-01-01

Using a comet assay technique, we investigated protective effects of. extremely high frequency electromagnetic radiation in combination with the damaging effect of X-ray irradiation, the effect of damaging agents hydrogen peroxide and methyl methanesulfonate on DNA in mouse whole blood leukocytes. It was shown that the preliminary exposure of the cells to low intensity pulse-modulated electromagnetic radiation (42.2 GHz, 0.1 mW/cm2, 20-min exposure, modulation frequencies of 1 and 16 Hz) caused protective effects decreasing the DNA damage by 20-45%. The efficacy of pulse-modulated electromagnetic radiation depended on the type of genotoxic agent and increased in a row methyl methanesulfonate--X-rays--hydrogen peroxide. Continuous electromagnetic radiation was ineffective. The mechanisms of protective effects may be connected with an induction of the adaptive response by nanomolar concentrations of reactive oxygen species formed by pulse-modulated electromagnetic radiation.

Numerical study of the inductive plasma coupling to ramp up the plasma density for the Linac4 H- ion source

NASA Astrophysics Data System (ADS)

Ohta, M.; Mattei, S.; Yasumoto, M.; Hatayama, A.; Lettry, J.

2014-02-01

In the Linac4 H- ion source, the plasma is generated by an RF antenna operated at 2 MHz. In order to investigate the conditions necessary for ramping up the plasma density of the Linac4 H- ion source in the low plasma density, a numerical study has been performed for a wide range of parameter space of RF coil current and initial pressure from H2 gas injection. We have employed an Electromagnetic Particle in Cell model, in which the collision processes have been calculated by a Monte Carlo method. The results have shown that the range of initial gas pressure from 2 to 3 Pa is suitable for ramping up plasma density via inductive coupling.

Modelling of resonant MEMS magnetic field sensor with electromagnetic induction sensing

NASA Astrophysics Data System (ADS)

Liu, Song; Xu, Huaying; Xu, Dehui; Xiong, Bin

2017-06-01

This paper presents an analytical model of resonant MEMS magnetic field sensor with electromagnetic induction sensing. The resonant structure vibrates in square extensional (SE) mode. By analyzing the vibration amplitude and quality factor of the resonant structure, the magnetic field sensitivity as a function of device structure parameters and encapsulation pressure is established. The developed analytical model has been verified by comparing calculated results with experiment results and the deviation between them is only 10.25%, which shows the feasibility of the proposed device model. The model can provide theoretical guidance for further design optimization of the sensor. Moreover, a quantitative study of the magnetic field sensitivity is conducted with respect to the structure parameters and encapsulation pressure based on the proposed model.

Electromagnetic interference with cardiac pacemakers and implantable cardioverter-defibrillators from low-frequency electromagnetic fields in vivo.

PubMed

Tiikkaja, Maria; Aro, Aapo L; Alanko, Tommi; Lindholm, Harri; Sistonen, Heli; Hartikainen, Juha E K; Toivonen, Lauri; Juutilainen, Jukka; Hietanen, Maila

2013-03-01

Electromagnetic interference (EMI) can pose a danger to workers with pacemakers and implantable cardioverter-defibrillators (ICDs). At some workplaces electromagnetic fields are high enough to potentially inflict EMI. The purpose of this in vivo study was to evaluate the susceptibility of pacemakers and ICDs to external electromagnetic fields. Eleven volunteers with a pacemaker and 13 with an ICD were exposed to sine, pulse, ramp, and square waveform magnetic fields with frequencies of 2-200 Hz using Helmholtz coil. The magnetic field flux densities varied to 300 µT. We also tested the occurrence of EMI from an electronic article surveillance (EAS) gate, an induction cooktop, and a metal inert gas (MIG) welding machine. All pacemakers were tested with bipolar settings and three of them also with unipolar sensing configurations. None of the bipolar pacemakers or ICDs tested experienced interference in any of the exposure situations. The three pacemakers with unipolar settings were affected by the highest fields of the Helmholtz coil, and one of them also by the EAS gate and the welding cable. The induction cooktop did not interfere with any of the unipolarly programmed pacemakers. Magnetic fields with intensities as high as those used in this study are rare even in industrial working environments. In most cases, employees can return to work after implantation of a bipolar pacemaker or an ICD, after an appropriate risk assessment. Pacemakers programmed to unipolar configurations can cause danger to their users in environments with high electromagnetic fields, and should be avoided, if possible.

Through-Metal-Wall Power Delivery and Data Transmission for Enclosed Sensors: A Review

PubMed Central

Yang, Ding-Xin; Hu, Zheng; Zhao, Hong; Hu, Hai-Feng; Sun, Yun-Zhe; Hou, Bao-Jian

2015-01-01

The aim of this review was to assess the current viable technologies for wireless power delivery and data transmission through metal barriers. Using such technologies sensors enclosed in hermetical metal containers can be powered and communicate through exterior power sources without penetration of the metal wall for wire feed-throughs. In this review, we first discuss the significant and essential requirements for through-metal-wall power delivery and data transmission and then we: (1) describe three electromagnetic coupling based techniques reported in the literature, which include inductive coupling, capacitive coupling, and magnetic resonance coupling; (2) present a detailed review of wireless ultrasonic through-metal-wall power delivery and/or data transmission methods; (3) compare various ultrasonic through-metal-wall systems in modeling, transducer configuration and communication mode with sensors; (4) summarize the characteristics of electromagnetic-based and ultrasound-based systems, evaluate the challenges and development trends. We conclude that electromagnetic coupling methods are suitable for through thin non-ferromagnetic metal wall power delivery and data transmission at a relatively low data rate; piezoelectric transducer-based ultrasonic systems are particularly advantageous in achieving high power transfer efficiency and high data rates; the combination of more than one single technique may provide a more practical and reliable solution for long term operation. PMID:26694392

Closed inductively coupled plasma cell

DOEpatents

Manning, Thomas J.; Palmer, Byron A.; Hof, Douglas E.

1990-01-01

A closed inductively coupled plasma cell generates a relatively high power, low noise plasma for use in spectroscopic studies. A variety of gases can be selected to form the plasma to minimize spectroscopic interference and to provide a electron density and temperature range for the sample to be analyzed. Grounded conductors are placed at the tube ends and axially displaced from the inductive coil, whereby the resulting electromagnetic field acts to elongate the plasma in the tube. Sample materials can be injected in the plasma to be excited for spectroscopy.

Synchronization stability and pattern selection in a memristive neuronal network.

PubMed

Wang, Chunni; Lv, Mi; Alsaedi, Ahmed; Ma, Jun

2017-11-01

Spatial pattern formation and selection depend on the intrinsic self-organization and cooperation between nodes in spatiotemporal systems. Based on a memory neuron model, a regular network with electromagnetic induction is proposed to investigate the synchronization and pattern selection. In our model, the memristor is used to bridge the coupling between the magnetic flux and the membrane potential, and the induction current results from the time-varying electromagnetic field contributed by the exchange of ion currents and the distribution of charged ions. The statistical factor of synchronization predicts the transition of synchronization and pattern stability. The bifurcation analysis of the sampled time series for the membrane potential reveals the mode transition in electrical activity and pattern selection. A formation mechanism is outlined to account for the emergence of target waves. Although an external stimulus is imposed on each neuron uniformly, the diversity in the magnetic flux and the induction current leads to emergence of target waves in the studied network.

Synchronization stability and pattern selection in a memristive neuronal network

NASA Astrophysics Data System (ADS)

Wang, Chunni; Lv, Mi; Alsaedi, Ahmed; Ma, Jun

2017-11-01

Spatial pattern formation and selection depend on the intrinsic self-organization and cooperation between nodes in spatiotemporal systems. Based on a memory neuron model, a regular network with electromagnetic induction is proposed to investigate the synchronization and pattern selection. In our model, the memristor is used to bridge the coupling between the magnetic flux and the membrane potential, and the induction current results from the time-varying electromagnetic field contributed by the exchange of ion currents and the distribution of charged ions. The statistical factor of synchronization predicts the transition of synchronization and pattern stability. The bifurcation analysis of the sampled time series for the membrane potential reveals the mode transition in electrical activity and pattern selection. A formation mechanism is outlined to account for the emergence of target waves. Although an external stimulus is imposed on each neuron uniformly, the diversity in the magnetic flux and the induction current leads to emergence of target waves in the studied network.

Development of induction current acquisition device based on ARM

NASA Astrophysics Data System (ADS)

Ji, Yanju; Liu, Xiyang; Huang, Wanyu; Yao, Jiang; Yuan, Guiyang; Hui, Luan; Guan, Shanshan

2018-03-01

We design an induction current acquisition device based on ARM in order to realize high resolution and high sampling rate of acquisition for the induction current in wire-loop. Considering its characteristics of fast attenuation and small signal amplitude, we use the method of multi-path fusion for noise suppression. In the paper, the design is carried out from three aspects of analog circuit and device selection, independent power supply structure and the electromagnetic interference suppression of high frequency. DMA and ping-pong buffer, as a new data transmission technology, solves real time storage problem of massive data. The performance parameters of ARM acquisition device are tested. The comparison test of ARM acquisition device and cRIO acquisition device is performed at different time constants. The results show that it has 120dB dynamic range, 47kHz bandwidth, 96kHz sampling rate, 5μV the smallest resolution, and its average error value is not more than 4%, which proves the high accuracy and stability of the device.

Endocardial Energy Harvesting by Electromagnetic Induction.

PubMed

Zurbuchen, Adrian; Haeberlin, Andreas; Bereuter, Lukas; Pfenniger, Alois; Bosshard, Simon; Kernen, Micha; Philipp Heinisch, Paul; Fuhrer, Juerg; Vogel, Rolf

2018-02-01

cardiac pacemakers require regular medical follow-ups to ensure proper functioning. However, device replacements due to battery depletion are common and account for ∼25% of all implantation procedures. Furthermore, conventional pacemakers require pacemaker leads which are prone to fractures, dislocations or isolation defects. The ensuing surgical interventions increase risks for the patients and costs that need to be avoided. in this study, we present a method to harvest energy from endocardial heart motions. We developed a novel generator, which converts the heart's mechanical into electrical energy by electromagnetic induction. A mathematical model has been introduced to identify design parameters strongly related to the energy conversion efficiency of heart motions and fit the geometrical constraints for a miniaturized transcatheter deployable device. The implemented final design was tested on the bench and in vivo. the mathematical model proved an accurate method to estimate the harvested energy. For three previously recorded heart motions, the model predicted a mean output power of 14.5, 41.9, and 16.9 μW. During an animal experiment, the implanted device harvested a mean output power of 0.78 and 1.7 μW at a heart rate of 84 and 160 bpm, respectively. harvesting kinetic energy from endocardial motions seems feasible. Implanted at an energetically favorable location, such systems might become a welcome alternative to extend the lifetime of cardiac implantable electronic device. the presented endocardial energy harvesting concept has the potential to turn pacemakers into battery- and leadless systems and thereby eliminate two major drawbacks of contemporary systems.

Perform Experiments on LINUS-O and LTX Imploding Liquid Liner Fusion Systems.

DTIC Science & Technology

1982-08-27

EXPERIMENTS .. .. .. ... 3 III. HOMOPOLAR GENERATOR/INDUCTOR POWER SUPPLY EXPERIMENTS. 11 IV. PLASMA SWITCH EXPERIMENTS. .. .. .. .... . ..... 18 V... homopolar generator (HPG) inductive load system. 0 Conduct an electromagnetic pulse (EMP) simulation demonstration using the NRL HPG/inductive storage...suggest solutions to the unstable flow problem, the research was suspended due to the program redirection. -10- IT III. HOMOPOLAR GENERATOR/INDUCTOR POWER

The Use of Electromagnetic Induction Techniques for Soil Mapping

NASA Astrophysics Data System (ADS)

Brevik, Eric C.; Doolittle, Jim

2015-04-01

Soils have high natural spatial variability. This has been recognized for a long time, and many methods of mapping that spatial variability have been investigated. One technique that has received considerable attention over the last ~30 years is electromagnetic induction (EMI). Particularly when coupled with modern GPS and GIS systems, EMI techniques have allowed the rapid and relatively inexpensive collection of large spatially-related data sets that can be correlated to soil properties that either directly or indirectly influence electrical conductance in the soil. Soil electrical conductivity is directly controlled by soil water content, soluble salt content, clay content and mineralogy, and temperature. A wide range of indirect controls have been identified, such as soil organic matter content and bulk density; both influence water relationships in the soil. EMI techniques work best in areas where there are large changes in one soil property that influences soil electrical conductance, and don't work as well when soil properties that influence electrical conductance are largely homogenous. This presentation will present examples of situations where EMI techniques were successful as well as a couple of examples of situations where EMI was not so useful in mapping the spatial variability of soil properties. Reasons for both the successes and failures will be discussed.

Dipole Models for UXO Discrimination at Live Sites

DTIC Science & Technology

2017-05-01

Discriminator CCR Combined Classifier Ranking cm Centimeter(s) EM Electromagnetic EMI Electromagnetic Induction ESTCP Environmental Security Technology...fraction of the anomalies as arising from non-hazardous items that could be safely left in the ground. Of particular note, the contractor EM -61-MK2 cart...use of classification metrics applied to production quality EM - 61 data, it was possible to significantly reduce the number of clutter items excavated

Update on Phelix Pulsed-Power Hydrodynamics Experiments and Modeling

DTIC Science & Technology

2013-06-01

underway to assess the feasibility of using the PHELIX driver as an electromagnetic launcher for planer shock-physics experiments. I. INTRODUCTION...inductance loads. Cylindrical liners or planer flyer plates can achieve km/s velocities and kbar pressures. A schematic of PHELIX is shown in Figure 1. Each...using the PHELIX driver as an electromagnetic launcher for planer shock-physics experiments. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17

Velocity damper for electromagnetically levitated materials

DOEpatents

Fox, R.J.

1994-06-07

A system for damping oscillatory and spinning motions induced in an electromagnetically levitated material is disclosed. Two opposed field magnets are located orthogonally to the existing levitation coils for providing a DC quadrupole field (cusp field) around the material. The material used for generating the DC quadrupole field must be nonconducting to avoid eddy-current heating and of low magnetic permeability to avoid distorting the induction fields providing the levitation. 1 fig.

Practical UXO Classification: Enhanced Data Processing Strategies for Technology Transition - Fort Ord: Dynamic and Cued Metalmapper Processing and Classification

DTIC Science & Technology

2017-06-06

OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for...Geophysical Mapping, Electromagnetic Induction, Instrument Verification Strip, Time Domain Electromagnetic, Unexploded Ordnance 16. SECURITY...Munitions Response QA Quality Assurance QC Quality Control ROC Receiver Operating Characteristic RTK Real- time Kinematic s Second SNR

Transformer modeling for low- and mid-frequency electromagnetic transients simulation

NASA Astrophysics Data System (ADS)

Lambert, Mathieu

In this work, new models are developed for single-phase and three-phase shell-type transformers for the simulation of low-frequency transients, with the use of the coupled leakage model. This approach has the advantage that it avoids the use of fictitious windings to connect the leakage model to a topological core model, while giving the same response in short-circuit as the indefinite admittance matrix (BCTRAN) model. To further increase the model sophistication, it is proposed to divide windings into coils in the new models. However, short-circuit measurements between coils are never available. Therefore, a novel analytical method is elaborated for this purpose, which allows the calculation in 2-D of short-circuit inductances between coils of rectangular cross-section. The results of this new method are in agreement with the results obtained from the finite element method in 2-D. Furthermore, the assumption that the leakage field is approximately 2-D in shell-type transformers is validated with a 3-D simulation. The outcome of this method is used to calculate the self and mutual inductances between the coils of the coupled leakage model and the results are showing good correspondence with terminal short-circuit measurements. Typically, leakage inductances in transformers are calculated from short-circuit measurements and the magnetizing branch is calculated from no-load measurements, assuming that leakages are unimportant for the unloaded transformer and that magnetizing current is negligible during a short-circuit. While the core is assumed to have an infinite permeability to calculate short-circuit inductances, and it is a reasonable assumption since the core's magnetomotive force is negligible during a short-circuit, the same reasoning does not necessarily hold true for leakage fluxes in no-load conditions. This is because the core starts to saturate when the transformer is unloaded. To take this into account, a new analytical method is developed in this dissertation, which removes the contributions of leakage fluxes to properly calculate the magnetizing branches of the new models. However, in the new analytical method for calculating short-circuit inductances (as with other analytical methods), eddy-current losses are neglected. Similarly, winding losses are omitted in the coupled leakage model and in the new analytical method to remove leakage fluxes to calculate core parameters from no-load tests. These losses will be taken into account in future work. Both transformer models presented in this dissertation are based on the classical hypothesis that flux can be discretized into flux tubes, which is also the assumption used in a category of models called topological models. Even though these models are physically-based, there exist many topological models for a given transformer geometry. It is shown in this work that these differences can be explained in part through the concepts of divided and integral fluxes, and it is explained that divided approach is the result of mathematical manipulations, while the integral approach is more "physically-accurate". Furthermore, it is demonstrated, for the special case of a two-winding single-phase transformer, that the divided leakage inductances have to be nonlinear for both approaches to be equivalent. Even between models of the divided or integral approach models, there are differences, which arise from the particular choice of so-called flux paths" (tubes). This arbitrariness comes from the fact that with the classical hypothesis that magnetic flux can be confined into predefined flux tubes (leading to classical magnetic circuit theory), it is assumed that flux cannot leak from the sides of flux tubes. Therefore, depending on the transformer's operation conditions (degree of saturation, short-circuit, etc.), this can lead to different choices of flux tubes and different models. In this work, a new theoretical framework is developed to allow flux to leak from the sides of the tube, and generalized to include resistances and capacitances in what is called electromagnetic circuit theory. Also, it is explained that this theory is actually equivalent to what is called finite formulations (such as the finite element method), which bridges the gap between circuit theory and discrete electromagnetism. Therefore, this enables not only to develop topologically-correct transformer models, where electric and magnetic circuits are defined on dual meshes, but also rotating machine and transmission lines models (wave propagation can be taken into account).

An overview of landmine detection with emphasis on electromagnetic approaches

NASA Astrophysics Data System (ADS)

Das, Yogadhish

2003-04-01

Human suffering caused by antipersonnel landmines left over from previous conflicts has only recently received significant public exposure. However, considerable amount of research on how to detect and deal with buried landmines has been carried out at least since the second world war. The research has encompassed a wide range of technologies and large sums of money have been spent. Despite these efforts there is still no operationally satisfactory solution, especially to the detection problem. This lack of success is attributable to the difficulty of the problem and the high degree of effectiveness demanded of any proposed solution. The many landmine detection approaches can be divided into two broad categories: (1)approaches primarily aimed at detecting the casing of the landmine (physical properties of its explosive content may also have some influence) and (2)approaches aimed at directly detecting the explosive contents. Examples of techniques belonging to the first group are electromagnetic induction, ground probing radar and other high frequency electromagnetic techniques, acoustics and other mechanical techniques, and infrared. Trace explosive vapour detection, thermalneutron activation and nuclear quadrupole resonance are examples of the second group. Following a brief introduction to nature of the landmine problem and the many technologies that have been explored to solve it, the presentation will focus on some of the detection approaches based on electromagnetic techniques. In particular, the state of the art in electromagnetic induction detection will be reviewed and required future research and development in this area will be presented.

Nonsmooth, nonconvex regularizers applied to linear electromagnetic inverse problems

NASA Astrophysics Data System (ADS)

Hidalgo-Silva, H.; Gomez-Trevino, E.

2017-12-01

Tikhonov's regularization method is the standard technique applied to obtain models of the subsurface conductivity distribution from electric or electromagnetic measurements by solving UT (m) = | F (m) - d |2 + λ P(m). The second term correspond to the stabilizing functional, with P (m) = | ∇ m |2 the usual approach, and λ the regularization parameter. Due to the roughness penalizer inclusion, the model developed by Tikhonov's algorithm tends to smear discontinuities, a feature that may be undesirable. An important requirement for the regularizer is to allow the recovery of edges, and smooth the homogeneous parts. As is well known, Total Variation (TV) is now the standard approach to meet this requirement. Recently, Wang et.al. proved convergence for alternating direction method of multipliers in nonconvex, nonsmooth optimization. In this work we present a study of several algorithms for model recovering of Geosounding data based on Infimal Convolution, and also on hybrid, TV and second order TV and nonsmooth, nonconvex regularizers, observing their performance on synthetic and real data. The algorithms are based on Bregman iteration and Split Bregman method, and the geosounding method is the low-induction numbers magnetic dipoles. Non-smooth regularizers are considered using the Legendre-Fenchel transform.

Research on a New Method of Estimating the Potential Depth of Slope Failure Using the Airborne Electromagnetic Survey

NASA Astrophysics Data System (ADS)

Seto, Shuji; Takahara, Teruyoshi; Kinoshita, Atsuhiko; Mizuno, Hideaki; Kawato, Katsushi; Okumura, Minoru; Kageura, Ryouta

2017-04-01

In Japan, at Ontake volcano in 1984 and Kurikoma volcano in 2008, parts of the volcanoes collapsed and large-scale sediment-related disasters occurred. These disasters were unrelated to volcanic eruption directly. We conducted the case studies by using the airborne electromagnetic surveys to investigate the slopes likely to induce landslides on such volcanoes. The airborne electromagnetic surveys are the effective exploration tool when we investigate in extreme environments that person can't enter and it's necessary to investigate with wide range by a short time. The surveys were conducted by using a helicopter carrying the survey instruments; this method of non-contact investigation acquires resistivity data by the electromagnetic induction. In Japan, the surveys were conducted of 15 active volcanoes where volcanic disasters could have serious social implications. These cases focused on the seeking for the possible slopes that landslides would occur. However, the depth of the slope failure was not evaluated. Therefore in the study, we proposed a new method to determine the potential depth of slope failure. First, we categorized the three characteristics as the cap rock type, the extended collapse type, and the landslide type on the basis of collapsed cases and paid attention to the slope of the cap rock type and also defined the collapse range based on the topography and geological properties. Second, we analyzed resistivity structure about collapsed cases with the differential filter and made clear that collapse occurred in the depth which resistivity suddenly changes. In other volcanoes, we could estimate failure depth by extracting the part which resistivity suddenly changes. In the study, we use the three volcanoes as the main cases, Hokkaido Komagatake, Asama Volcano, and Ontake volcano.

Electromagnetic interference reduction using electromagnetic bandgap structures in packages, enclosures, cavities, and antennas

NASA Astrophysics Data System (ADS)

Mohajer Iravani, Baharak

Electromagnetic interference (EMI) is a source of noise problems in electronic devices. The EMI is attributed to coupling between sources of radiation and components placed in the same media such as package or chassis. This coupling can be either through conducting currents or through radiation. The radiation of electromagnetic (EM) fields is supported by surface currents. Thus, minimizing these surface currents is considered a major and critical step to suppress EMI. In this work, we present novel strategies to confine surface currents in different applications including packages, enclosures, cavities, and antennas. The efficiency of present methods of EM noise suppression is limited due to different drawbacks. For example, the traditional use of lossy materials and absorbers suffers from considerable disadvantages including mechanical and thermal reliability leading to limited life time, cost, volume, and weight. In this work, we consider the use of Electromagnetic Band Gap (EBG) structures. These structures are suitable for suppressing surface currents within a frequency band denoted as the bandgap. Their design is straight forward, they are inexpensive to implement, and they do not suffer from the limitations of the previous methods. A new method of EM noise suppression in enclosures and cavity-backed antennas using mushroom-type EBG structures is introduced. The effectiveness of the EBG as an EMI suppresser is demonstrated using numerical simulations and experimental measurements. To allow integration of EBGs in printed circuit boards and packages, novel miniaturized simple planar EBG structures based on use of high-k dielectric material (epsilonr > 100) are proposed. The design consists of meander lines and patches. The inductive meander lines serve to provide current continuity bridges between the capacitive patches. The high-k dielectric material increases the effective capacitive load substantially in comparison to commonly used material with much lower dielectric constant. Meander lines can increase the effective inductive load which pushes down the lower edge of bandgap, thus resulting in a wider bandgap. Simulation results are included to show that the proposed EBG structures provide very wide bandgap (˜10GHz) covering the multiple harmonics of of currently available microprocessors and its harmonics. To speed up the design procedure, a model based on combination of lumped elements and transmission lines is proposed. The derived model predicts accurately the starting edge of bandgap. This result is verified with full-wave analysis. Finally, another novel compact wide band mushroom-type EBG structure using magneto-dielectric materials is designed. Numerical simulations show that the proposed EBG structure provides in-phase reflection bandgap which is several times greater than the one obtained from a conventional EBG operating at the same frequency while its cell size is smaller. This type of EBG structure can be used efficiently as a ground plane for low-profile wideband antennas.

Multimode electromagnetic target discriminator: preliminary data results

NASA Astrophysics Data System (ADS)

Black, Christopher J.; McMichael, Ian T.; Nelson, Carl V.

2004-09-01

This paper describes the Multi-mode Electromagnetic Target Discriminator (METD) sensor and presents preliminary results from recent field experiments. The METD sensor was developed for the US Army RDECOM NVESD by The Johns Hopkins University Applied Physics Laboratory. The METD, based on the technology of the previously developed Electromagnetic Target Discriminator (ETD), is a spatial scanning electromagnetic induction (EMI) sensor that uses both the time-domain (TD) and the frequency-domain (FD) for target detection and classification. Data is collected with a custom data acquisition system and wirelessly transmitted to a base computer. We show that the METD has a high signal-to-noise ratio (SNR), the ability to detect voids created by plastic anti-tank (AT) mines, and is practical for near real-time data processing.

Famous optician: James Clerk Maxwell

NASA Astrophysics Data System (ADS)

Haidar, Riad

2018-04-01

Mainly known for his unifying theory of electricity, magnetism and induction, James Clerk Maxwell also concluded that light was an electromagnetic wave, and was responsible for the first true colour photograph.

Designs for improving electromagnetic acoustic transducers’ excitation performance

NASA Astrophysics Data System (ADS)

He, Jianpeng; Xu, Ke; Ren, Weiping

2018-06-01

The main drawback of electromagnetic acoustic transducers (EMATs) is their low energy transition efficiency. For the purpose of increasing the amplitude of the received signal, a ferrite core (FC) and a bias magnet (BM) are utilized respectively to improve the EMAT’s excitation performance in this paper. It indicates that the new configurations can increase the peak-to-peak amplitude of the received signal by a factor of 2.7 and 2.9, respectively. The reasons for the signal enhancement are also investigated through simulation and experimental methods. For the FC EMAT, improvement is achieved due to the enhancement of the dynamic magnetic field and the increase of coil inductance. In comparison, the change of the magnetostrictive transduction mechanism leads to the signal enhancement for the BM EMAT. The bias magnet magnetized the surface of the steel plate, which changes the signal excitation mechanism from domain wall movement to reversible domain rotations.

Theory of topological insulator waveguides: polarization control and the enhancement of the magneto-electric effect

PubMed Central

Crosse, J. A.

2017-01-01

Topological insulators subject to a time-reversal-symmetry-breaking perturbation are predicted to display a magneto-electric effect that causes the electric and magnetic induction fields to mix at the material’s surface. This effect induces polarization rotations of between ≈1–10 mrad per interface in an incident plane-polarized electromagnetic wave normal to a multilayered structure. Here we show, theoretically and numerically, that by using a waveguide geometry with a topological insulator guide layer and magneto-dielectric cladding it is possible to achieve rotations of ≈100 mrad and generate an elliptical polarization with only a three-layered structure. This geometry is beneficial, not only as a way to enhance the magneto-electric effect, rendering it easier to observe, but also as a method for controlling the polarization of electromagnetic radiation. PMID:28220875

Particle-in-cell simulations of electron beam control using an inductive current divider

DOE PAGES

Swanekamp, S. B.; Angus, J. R.; Cooperstein, G.; ...

2015-11-18

Kinetic, time-dependent, electromagnetic, particle-in-cell simulations of the inductive current divider are presented. The inductive current divider is a passive method for controlling the trajectory of an intense, hollow electron beam using a vacuum structure that inductively splits the beam’s return current. The current divider concept was proposed and studied theoretically in a previous publication [Phys. Plasmas 22, 023107 (2015)] A central post carries a portion of the return current (I 1) while the outer conductor carries the remainder (I 2) with the injected beam current given by I b=I 1+I 2. The simulations are in agreement with the theory whichmore » predicts that the total force on the beam trajectory is proportional to (I 2-I 1) and the force on the beam envelope is proportional to I b. For a fixed central post, the beam trajectory is controlled by varying the outer conductor radius which changes the inductance in the return-current path. The simulations show that the beam emittance is approximately constant as the beam propagates through the current divider to the target. As a result, independent control over both the current density and the beam angle at the target is possible by choosing the appropriate return-current geometry.« less

The gravitational analog of Faraday's induction law

NASA Astrophysics Data System (ADS)

Zile, Daniel; Overduin, James

2015-04-01

Michael Faraday, the discoverer of electromagnetic induction, was convinced that there must also be a gravitational analog of this law, and he carried out drop-tower experiments in 1849 to look for the electric current induced in a coil by changes in gravitational flux through the coil. This work, now little remembered, was in some ways the first investigation of what we would now call a unified-field theory. We revisit Faraday's experiments in the light of current knowledge and ask what might be learned if they were to be performed today. We then review the gravitational analog for Faraday's law that arises within the vector (or gravito-electromagnetic) approximation to Einstein's theory of general relativity in the weak-field, low-velocity limit. This law relates spinning masses and induced ``mass currents'' rather than spinning charges and electric currents, but is otherwise remarkably similar to its electromagnetic counterpart. The predicted effects are completely unobservable in everyday settings like those envisioned by Faraday, but are thought to be relevant in astrophysical contexts like the accretion disks around collapsed stars, thus bearing out Faraday's remarkable intuition. Undergraduate student.

Field coupling-induced pattern formation in two-layer neuronal network

NASA Astrophysics Data System (ADS)

Qin, Huixin; Wang, Chunni; Cai, Ning; An, Xinlei; Alzahrani, Faris

2018-07-01

The exchange of charged ions across membrane can generate fluctuation of membrane potential and also complex effect of electromagnetic induction. Diversity in excitability of neurons induces different modes selection and dynamical responses to external stimuli. Based on a neuron model with electromagnetic induction, which is described by magnetic flux and memristor, a two-layer network is proposed to discuss the pattern control and wave propagation in the network. In each layer, gap junction coupling is applied to connect the neurons, while field coupling is considered between two layers of the network. The field coupling is approached by using coupling of magnetic flux, which is associated with distribution of electromagnetic field. It is found that appropriate intensity of field coupling can enhance wave propagation from one layer to another one, and beautiful spatial patterns are formed. The developed target wave in the second layer shows some difference from target wave triggered in the first layer of the network when two layers are considered by different excitabilities. The potential mechanism could be pacemaker-like driving from the first layer will be encoded by the second layer.

ELECTROMAGNETIC STIRRING IN ZONE REFINING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Braun, I.; Frank, F.C.; Marshall, S.

1958-02-01

The efficiency of the zone refining process can obviously be increased by stirring the molten zone to disperse the impurity-rich layer at the solid- liquid surface. Induction heating is sometimes preferred to radiant heat because it produces more convection, but no marked improvement has been reported. Pfann and Dorsi(1967) have described a method of stirring the melt by passing an electric current through the ingot and compressing a magnetic field across the molten zone. Preliminary results obtained by using a rotating magnetic field us the stirring agent during the purification of aluminum are described. (A.C.)

EM Induction Experiment to Determine the Moment of a Magnet

ERIC Educational Resources Information Center

Najiya Maryam, K. M.

2014-01-01

If we drop a magnet through a coil, an emf is induced in the coil according to Faraday's law of electromagnetic induction. Here, such an experiment is done using expEYES kit. The plot of emf versus time has a specific shape with two peaks. A theoretical analysis of this graph is discussed here for both short and long cylindrical magnets.…

Overpulse railgun energy recovery circuit

DOEpatents

Honig, Emanuel M.

1989-01-01

In an electromagnetic launcher such as a railgun for propelling a projectile at high velocity, an overpulse energy recovery circuit is employed to transfer stored inductive energy from a source inductor to the railgun inductance to propel the projectile down the railgun. Switching circuitry and an energy transfer capacitor are used to switch the energy back to the source inductor in readiness for a repetitive projectile propelling cycle.

Counterpulse railgun energy recovery circuit

DOEpatents

Honig, Emanuel M.

1986-01-01

In an electromagnetic launcher such as a railgun for propelling a projectile at high velocity, a counterpulse energy recovery circuit is employed to transfer stored inductive energy from a source inductor to the railgun inductance to propel the projectile down the railgun. Switching circuitry and an energy transfer capacitor are used to switch the energy back to the source inductor in readiness for a repetitive projectile propelling cycle.

VLF electromagnetic investigations of the crater and central dome of Mount St. Helens, Washington

USGS Publications Warehouse

Towle, J.N.

1983-01-01

A very low frequency (VLF) electromagnetic induction survey in the crater of Mount St. Helens has identified several electrically conductive structures that appear to be associated with thermal anomalies and ground water within the crater. The most interesting of these conductive structures lies beneath the central dome. It is probably a partial melt of dacite similar to that comprising the June 1981 lobe of the central dome. ?? 1983.

Closed inductively coupled plasma cell

DOEpatents

Manning, T.J.; Palmer, B.A.; Hof, D.E.

1990-11-06

A closed inductively coupled plasma cell generates a relatively high power, low noise plasma for use in spectroscopic studies is disclosed. A variety of gases can be selected to form the plasma to minimize spectroscopic interference and to provide a electron density and temperature range for the sample to be analyzed. Grounded conductors are placed at the tube ends and axially displaced from the inductive coil, whereby the resulting electromagnetic field acts to elongate the plasma in the tube. Sample materials can be injected in the plasma to be excited for spectroscopy. 1 fig.

Design of Circular, Square, Single, and Multi-layer Induction Coils for Electromagnetic Priming Using Inductance Estimates

NASA Astrophysics Data System (ADS)

Fritzsch, Robert; Kennedy, Mark W.; Aune, Ragnhild E.

2018-02-01

Special induction coils used for electro magnetic priming of ceramic foam filters in liquid metal filtration have been designed using a combination of analytical and finite element modeling. Relatively simple empirical equations published by Wheeler in 1928 and 1982 have been used during the design process. The equations were found to accurately predict the z-component of the magnetic flux densities of both single- and multi-layer coils as verified both experimentally and by using COMSOL® 5.1 multiphysics simulations.

[Saccharomyces cerevisiae as a model organism for studying the carcinogenicity of non-ionizing electromagnetic fields and radiation].

PubMed

Voĭchuk, S I

2014-01-01

Medical and biological aspects of the effects of non-ionizing electromagnetic (EM) fields and radiation on human health are the important issues that have arisen as a result of anthropogenic impact on the biosphere. Safe use of man-made sources of non-ionizing electromagnetic fields and radiation in a broad range of frequencies--static, radio-frequency and microwave--is a subject of discussions and speculations. The main problem is the lack of understanding of the mechanism(s) of reception of EMFs by living organisms. In this review we have analyzed the existing literature data regarding the effects of the electromagnetic radiation on the model eukaryotic organism--yeast Saccharomyces cerevisiae. An attempt was made to estimate the probability of induction of carcinogenesis in humans under the influence of magnetic fields and electromagnetic radiation of extremely low frequency, radio frequency and microwave ranges.

Some Student Conceptions of Electromagnetic Induction

NASA Astrophysics Data System (ADS)

Thong, Wai Meng; Gunstone, Richard

2008-01-01

Introductory electromagnetism is a central part of undergraduate physics. Although there has been some research into student conceptions of electromagnetism, studies have been sparse and separated. This study sought to explore second year physics students’ conceptions of electromagnetism, to investigate to what extent the results from the present study are similar to these results from other studies, and to uncover any new forms of alternative conceptions. Data for this study came from 15 in-depth interviews. Three previously unreported alternative conceptions were identified in the study: 1) induced current varies proportionately with current in solenoid; 2) there must be contact between magnetic flux and the external coil in order for any emf to be induced in the coil; 3) coulombic or electrostatic potential difference is present in an induced electric field. These alternative conceptions were manifested in these students’ explanations of electromagnetic phenomena presented to them during the interviews.

Conversion of electromagnetic energy in Z-pinch process of single planar wire arrays at 1.5 MA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liangping, Wang; Mo, Li; Juanjuan, Han

The electromagnetic energy conversion in the Z-pinch process of single planar wire arrays was studied on Qiangguang generator (1.5 MA, 100 ns). Electrical diagnostics were established to monitor the voltage of the cathode-anode gap and the load current for calculating the electromagnetic energy. Lumped-element circuit model of wire arrays was employed to analyze the electromagnetic energy conversion. Inductance as well as resistance of a wire array during the Z-pinch process was also investigated. Experimental data indicate that the electromagnetic energy is mainly converted to magnetic energy and kinetic energy and ohmic heating energy can be neglected before the final stagnation. Themore » kinetic energy can be responsible for the x-ray radiation before the peak power. After the stagnation, the electromagnetic energy coupled by the load continues increasing and the resistance of the load achieves its maximum of 0.6–1.0 Ω in about 10–20 ns.« less

Hydrogeological Characterization of the Upper Camp Bird III Rock Glacier in the San Juan Mountains, Colorado Using Electromagnetic Induction

NASA Astrophysics Data System (ADS)

Granados-Aguilar, R.; Giardino, J. R.; Everett, M. E.; Pondthai, P.; Ramsey, C. E.; Mmasa, D.; Witek, M.; Rodriguez, R.

2017-12-01

Global change is the set of variations in environmental conditions that significantly impact the Earth systems. Climate, sea level, land-use/land-cover, and atmospheric composition changes are the most recognized environmental global changes. Impacts of climatic variability can include decreased rainfall, snowpack, shorter snow seasons, and changes in the timing, frequency, and intensity of precipitation events in some areas of the world, whereas other regions can suffer from the opposite effects leading to events such as landslides, flooding and extraordinary snowfall. The proposed research intends to provide a characterization of the internal structure, including water storages, pathways, and thresholds, as well as an estimation of the volume of ice stored within a rock glacier to evaluate its potential as a freshwater resources. The area of study corresponds to the third level of Camp Bird Mine in Ouray, Colorado. The tongue-shaped active rock glacier of interest, Upper Camp Bird III, has not been previously studied in detail. The predominant lithologies in the study area are Mesozoic and Cenozoic. Orogenic events caused alteration of sedimentary and intrusive igneous rock as mineral rich, hydrothermal fluids deposited economically valuable minerals in the region. Traditional geological and geomorphological mapping techniques will be complemented with the use of unmanned aerial vehicles (UAV). To obtain a detailed representation of the internal structure and determine the boundaries between resistive (rocks, sediment, and ice) and conductive materials (water and ore deposits) of the rock glacier, time-domain and frequency-domain methods will be implemented. The G-TEM by Geonics Ltd. is an innovative controlled-source time-domain electromagnetic induction system. Using the G-TEM, the distribution of electrical conductivity in the subsurface can be mapped in order to characterize the internal structure of the rock glacier from 5-10 m depth and below. The EM Profiler is a frequency-domain electromagnetic induction system that will be used for the investigation of the uppermost layers of the rock glacier. For the proposed research, the use of two different systems will provide continuity across the data sets and will help validate the measurements recorded with the new equipment.

Optimal design of a for middle-low-speed maglev trains

NASA Astrophysics Data System (ADS)

Xiao, Song; Zhang, Kunlun; Liu, Guoqing; Jing, Yongzhi; Sykulski, Jan K.

2018-04-01

A middle-low-speed maglev train is supported by an electromagnetic force between the suspension electromagnet (EM) and the steel rail and is driven by a linear induction motor. The capability of the suspension system has a direct bearing on safety and the technical and economic performance of the train. This paper focuses on the dependence of the electromagnetic force on the structural configuration of the EM with the purpose of improving performance of a conventional EM. Finally, a novel configuration is proposed of a hybrid suspension magnet, which combines permanent magnets and coils, in order to increase the suspension force while reducing the suspension power loss.

Electromagnetic mapping of buried paleochannels in eastern Abu Dhabi Emirate, U.A.E.

USGS Publications Warehouse

Fitterman, D.V.; Menges, C.M.; Al Kamali, A.M.; Essa, Jama F.

1991-01-01

Transient electromagnetic soundings and terrain conductivity meter measurements were used to map paleochannel geometry in the Al Jaww Plain of eastern Abu Dhabi Emirate, U.A.E. as part of an integrated hydrogeologic study of the Quaternary alluvial aquifer system. Initial interpretation of the data without benefit of well log information was able to map the depth to a conductive clay layer of Tertiary age that forms the base of the aquifer. Comparison of the results with induction logs reveals that a resistive zone exists that was incorporated into the interpretation and its lateral extent mapped with the transient electromagnetic sounding data. ?? 1991.

Physics Notes

ERIC Educational Resources Information Center

School Science Review, 1972

1972-01-01

Twelve ideas are presented for physics teachers to implement in the laboratory or classroom. Topics covered include electromagnetic induction, microbalance, capacitors, determination of light velocity, and the compound pendulum. Information regarding laboratory equipment is also provided. (PS)

Effect of Inductive Coil Geometry on the Thrust Efficiency of a Microwave Assisted Discharge Inductive Plasma Accelerator

NASA Technical Reports Server (NTRS)

Hallock, Ashley; Polzin, Kurt; Emsellem, Gregory

2012-01-01

Pulsed inductive plasma thrusters [1-3] are spacecraft propulsion devices in which electrical energy is capacitively stored and then discharged through an inductive coil. The thruster is electrodeless, with a time-varying current in the coil interacting with a plasma covering the face of the coil to induce a plasma current. Propellant is accelerated and expelled at a high exhaust velocity (O(10-100 km/s)) by the Lorentz body force arising from the interaction of the magnetic field and the induced plasma current. While this class of thruster mitigates the life-limiting issues associated with electrode erosion, pulsed inductive plasma thrusters require high pulse energies to inductively ionize propellant. The Microwave Assisted Discharge Inductive Plasma Accelerator (MAD-IPA) [4, 5] is a pulsed inductive plasma thruster that addressees this issue by partially ionizing propellant inside a conical inductive coil via an electron cyclotron resonance (ECR) discharge. The ECR plasma is produced using microwaves and permanent magnets that are arranged to create a thin resonance region along the inner surface of the coil, restricting plasma formation, and in turn current sheet formation, to a region where the magnetic coupling between the plasma and the inductive coil is high. The use of a conical theta-pinch coil is under investigation. The conical geometry serves to provide neutral propellant containment and plasma plume focusing that is improved relative to the more common planar geometry of the Pulsed Inductive Thruster (PIT) [2, 3], however a conical coil imparts a direct radial acceleration of the current sheet that serves to rapidly decouple the propellant from the coil, limiting the direct axial electromagnetic acceleration in favor of an indirect acceleration mechanism that requires significant heating of the propellant within the volume bounded by the current sheet. In this paper, we describe thrust stand measurements performed to characterize the performance (specific impulse, thrust efficiency) of the MAD-IPA thruster. Impulse data are obtained at various pulse energies, mass flow rates and inductive coil. geometries. Dependencies on these experimental parameters are discussed in the context of the current sheet formation and electromagnetic plasma acceleration processes.

Electromagnetic receiver with capacitive electrodes and triaxial induction coil for tunnel exploration

NASA Astrophysics Data System (ADS)

Kai, Chen; Sheng, Jin; Wang, Shun

2017-09-01

A new type of electromagnetic (EM) receiver has been developed by integrating four capacitive electrodes and a triaxial induction coil with an advanced data logger for tunnel exploration. The new EM receiver can conduct EM observations in tunnels, which is one of the principal goals of surface-tunnel-borehole EM detection for deep ore deposit mapping. The use of capacitive electrodes enables us to record the electrical field (E-field) signals from hard rock surfaces, which are high-resistance terrains. A compact triaxial induction coil integrates three independent induction coils for narrow-tunnel exploration applications. A low-time-drift-error clock source is developed for tunnel applications where GPS signals are unavailable. The three main components of our tunnel EM receiver are: (1) four capacitive electrodes for measuring the E-field signal without digging in hard rock regions; (2) a triaxial induction coil sensor for audio-frequency magnetotelluric and controlled-source audio-frequency magnetotelluric signal measurements; and (3) a data logger that allows us to record five-component MT signals with low noise levels, low time-drift-error for the clock source, and high dynamic range. The proposed tunnel EM receiver was successfully deployed in a mine that exhibited with typical noise characteristics. [Figure not available: see fulltext. Caption: The new EM receiver can conduct EM observations in tunnels, which is one of the principal goals of the surface-tunnel-borehole EM (STBEM) detection for deep ore deposit mapping. The use of a capacitive electrode enables us to record the electrical field (E-field) signals from hard rock surfaces. A compact triaxial induction coil integrated three induction coils, for narrow-tunnel applications.

Electromagnetic pulsed thermography for natural cracks inspection

PubMed Central

Gao, Yunlai; Tian, Gui Yun; Wang, Ping; Wang, Haitao; Gao, Bin; Woo, Wai Lok; Li, Kongjing

2017-01-01

Emerging integrated sensing and monitoring of material degradation and cracks are increasingly required for characterizing the structural integrity and safety of infrastructure. However, most conventional nondestructive evaluation (NDE) methods are based on single modality sensing which is not adequate to evaluate structural integrity and natural cracks. This paper proposed electromagnetic pulsed thermography for fast and comprehensive defect characterization. It hybrids multiple physical phenomena i.e. magnetic flux leakage, induced eddy current and induction heating linking to physics as well as signal processing algorithms to provide abundant information of material properties and defects. New features are proposed using 1st derivation that reflects multiphysics spatial and temporal behaviors to enhance the detection of cracks with different orientations. Promising results that robust to lift-off changes and invariant features for artificial and natural cracks detection have been demonstrated that the proposed method significantly improves defect detectability. It opens up multiphysics sensing and integrated NDE with potential impact for natural understanding and better quantitative evaluation of natural cracks including stress corrosion crack (SCC) and rolling contact fatigue (RCF). PMID:28169361

Performance of Flow and Heat Transfer in a Hot-Dip Round Coreless Galvanizing Bath

NASA Astrophysics Data System (ADS)

Yue, Qiang; Zhang, Chengbo; Xu, Yong; Zhou, Li; Kong, Hui; Wang, Jia

2017-04-01

Flow field in a coreless hot-dip galvanizing pot was investigated through a water modeling experiment. The corresponding velocity vector was measured using an acoustic Doppler velocimeter. The flow field of molten zinc in the bath was also analyzed. Steel strip velocities from 1.7 to 2.7 m/s were adopted to determine the effect of steel strip velocity on the molten zinc flow in the bath. A large vortex filled the space at the right side of the sink roll, under linear speed from 1.0 to 2.7 m/s and width from 1.0 to 1.3 m of the steel strip, because of the effects of wall and shear stress. The results of the water modeling experiment were compared with those of numerical simulations. In the simulation, Maxwell equations were solved using finite element method to obtain magnetic flux density, electromagnetic force, and Joule heating. The Joule heating rate reached the maximum and minimum values near the side wall and at the core of the bath, respectively, because of the effect of skin and proximity. In an industrial-sized model, the molten zinc flow and temperature fields driven by electromagnetic force and Joule heating in the inductor of a coreless galvanizing bath were numerically simulated. The results indicated that the direction of electromagnetic force concentrated at the center of the galvanizing pot horizontal planes and exerted a pinch effect on molten zinc. Consequently, molten zinc in the pot was stirred by electromagnetic force. Under molten zinc flow and electromagnetic force stirring, the temperature of the molten zinc became homogeneous throughout the bath. This study provides a basis for optimizing electromagnetic fields in coreless induction pot and fine-tuning the design of steel strip parameters.

Project MANTIS: A MANTle Induction Simulator for coupling geodynamic and electromagnetic modeling

NASA Astrophysics Data System (ADS)

Weiss, C. J.

2009-12-01

A key component to testing geodynamic hypotheses resulting from the 3D mantle convection simulations is the ability to easily translate the predicted physiochemical state to the model space relevant for an independent geophysical observation, such as earth's seismic, geodetic or electromagnetic response. In this contribution a new parallel code for simulating low-frequency, global-scale electromagnetic induction phenomena is introduced that has the same Earth discretization as the popular CitcomS mantle convection code. Hence, projection of the CitcomS model into the model space of electrical conductivity is greatly simplified, and focuses solely on the node-to-node, physics-based relationship between these Earth parameters without the need for "upscaling", "downscaling", averaging or harmonizing with some other model basis such as spherical harmonics. Preliminary performance tests of the MANTIS code on shared and distributed memory parallel compute platforms shows favorable scaling (>70% efficiency) for up to 500 processors. As with CitcomS, an OpenDX visualization widget (VISMAN) is also provided for 3D rendering and interactive interrogation of model results. Details of the MANTIS code will be briefly discussed here, focusing on compatibility with CitcomS modeling, as will be preliminary results in which the electromagnetic response of a CitcomS model is evaluated. VISMAN rendering of electrical tomography-derived electrical conductivity model overlain by an a 1x1 deg crustal conductivity map. Grey scale represents the log_10 magnitude of conductivity [S/m]. Arrows are horiztonal components of a hypothetical magnetospheric source field used to electromagnetically excite the conductivity model.

Effect of Inductive Coil Geometry and Current Sheet Trajectory of a Conical Theta Pinch Pulsed Inductive Plasma Accelerator

NASA Technical Reports Server (NTRS)

Hallock, Ashley K.; Polzin, Kurt A.; Bonds, Kevin W.; Emsellem, Gregory D.

2011-01-01

Results are presented demonstrating the e ect of inductive coil geometry and current sheet trajectory on the exhaust velocity of propellant in conical theta pinch pulsed induc- tive plasma accelerators. The electromagnetic coupling between the inductive coil of the accelerator and a plasma current sheet is simulated, substituting a conical copper frustum for the plasma. The variation of system inductance as a function of plasma position is obtained by displacing the simulated current sheet from the coil while measuring the total inductance of the coil. Four coils of differing geometries were employed, and the total inductance of each coil was measured as a function of the axial displacement of two sep- arate copper frusta both having the same cone angle and length as the coil but with one compressed to a smaller size relative to the coil. The measured relationship between total coil inductance and current sheet position closes a dynamical circuit model that is used to calculate the resulting current sheet velocity for various coil and current sheet con gura- tions. The results of this model, which neglects the pinching contribution to thrust, radial propellant con nement, and plume divergence, indicate that in a conical theta pinch ge- ometry current sheet pinching is detrimental to thruster performance, reducing the kinetic energy of the exhausting propellant by up to 50% (at the upper bound for the parameter range of the study). The decrease in exhaust velocity was larger for coils and simulated current sheets of smaller half cone angles. An upper bound for the pinching contribution to thrust is estimated for typical operating parameters. Measurements of coil inductance for three di erent current sheet pinching conditions are used to estimate the magnetic pressure as a function of current sheet radial compression. The gas-dynamic contribution to axial acceleration is also estimated and shown to not compensate for the decrease in axial electromagnetic acceleration that accompanies the radial compression of the plasma in conical theta pinches.

Hand-Held EMI Sensor Combined with Inertial Positioning for Cued UXO Discrimination - APG Standardized UXO Test Site

DTIC Science & Technology

2013-04-01

Measurement Tracking System (SAINT) with an advanced hand-held, time-domain electromagnetic sensor (TEM-HH) and document classification performance at...rejecting 77% of the clutter. 15. SUBJECT TERMS EMI, electromagnetic induction, UXO classification, UXO, IMU, inertial measurement unit, 16. SECURITY...U c. THIS PAGE U UU 19b. TELEPHONE NUMBER (include area code) 919-677-1560 Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. Z39.18

Ultra-high-frequency microwave response from flexible transparent Au electromagnetic metamaterial nanopatterned antenna.

PubMed

Liu, Dingxin; Niu, Jiebin; Zhu, Haolin; Zhang, Jianyong

2018-02-09

Flexible transparent materials are a hot spot in current research but also a key technical difficulty in industry. They are playing an increasingly important role in flexible transparent display applications such as organic light-emitting diodes, transparent electrodes, and so on. On the other hand, the present research on nanopatterned antennas is mainly concentrated on the optical frequency but rarely on the microwave (such as 3G, 4G, and 5G) and terahertz frequency band communications, where nanopatterned antennas can have many novel applications. To the authors' knowledge, this is the first paper that presents a method for preparing a flexible transparent Au electromagnetic metamaterial nanopatterned antenna. We study its free-space performance at ultra-high frequency and its application in electronic products such as smartphones, tablets, personal computers, and wearable devices (such as smart watches) which have the function of mobile communication. The experimental results showed that the transparency of the antenna designed and fabricated in this work can be as high as 94%, and its efficiency can reach 74.5%-91.9% of antennas commonly seen at present in academia and industry. By adjusting the capacitive and inductive reactance of the nanopatterned antenna's matching circuit, combined with its measured efficiency and 3D electromagnetic simulation results, we speculate on the mechanism of the Au electromagnetic metamaterial nanopatterned antenna with good performance.

Ultra-high-frequency microwave response from flexible transparent Au electromagnetic metamaterial nanopatterned antenna

NASA Astrophysics Data System (ADS)

Liu, Dingxin; Niu, Jiebin; Zhu, Haolin; Zhang, Jianyong

2018-02-01

Flexible transparent materials are a hot spot in current research but also a key technical difficulty in industry. They are playing an increasingly important role in flexible transparent display applications such as organic light-emitting diodes, transparent electrodes, and so on. On the other hand, the present research on nanopatterned antennas is mainly concentrated on the optical frequency but rarely on the microwave (such as 3G, 4G, and 5G) and terahertz frequency band communications, where nanopatterned antennas can have many novel applications. To the authors’ knowledge, this is the first paper that presents a method for preparing a flexible transparent Au electromagnetic metamaterial nanopatterned antenna. We study its free-space performance at ultra-high frequency and its application in electronic products such as smartphones, tablets, personal computers, and wearable devices (such as smart watches) which have the function of mobile communication. The experimental results showed that the transparency of the antenna designed and fabricated in this work can be as high as 94%, and its efficiency can reach 74.5%-91.9% of antennas commonly seen at present in academia and industry. By adjusting the capacitive and inductive reactance of the nanopatterned antenna’s matching circuit, combined with its measured efficiency and 3D electromagnetic simulation results, we speculate on the mechanism of the Au electromagnetic metamaterial nanopatterned antenna with good performance.

The magnetic fields generated by the tsunami of February 27, 2010

NASA Astrophysics Data System (ADS)

Nair, M. C.; Maus, S.; Neetu, S.; Kuvshinov, A. V.; Chulliat, A.

2010-12-01

It has long been speculated that tsunamis produce measurable perturbations in the magnetic field. Recent deployments of highly accurate magnetometers and the exceptionally deep solar minimum provided ideal conditions to identify these small signals for the tsunami resulting from the strong Chilean earthquake on February 27, 2010. We find that the magnetic observatory measurements on Easter Island, 3500 km west of the epicenter, show a periodic signal of 1 nT, coincident in time with recordings from the local tide gauge. The amplitude of this signal is consistent with the sea level variation caused by the tsunami in the open ocean near Easter Island through a scaling method proposed by Tyler (2005). In order to have a better understanding of this process, we predict the magnetic fields induced by the Chile tsunami using a barotropic-shallow-water model along with a three-dimensional electromagnetic induction code (Kuvshinov et al., 2002). Initial results indicate good agreement between the predicted and observed magnetic signals at Easter Island. The detection of these magnetic signals represents a milestone in understanding tsunami-induced electromagnetic effects. However, magnetospheric disturbances could limit the practical utility of tsunami electromagnetic monitoring to periods of low solar activity.

Two-Stage Design Method for Enhanced Inductive Energy Transmission with Q-Constrained Planar Square Loops.

PubMed

Eteng, Akaa Agbaeze; Abdul Rahim, Sharul Kamal; Leow, Chee Yen; Chew, Beng Wah; Vandenbosch, Guy A E

2016-01-01

Q-factor constraints are usually imposed on conductor loops employed as proximity range High Frequency Radio Frequency Identification (HF-RFID) reader antennas to ensure adequate data bandwidth. However, pairing such low Q-factor loops in inductive energy transmission links restricts the link transmission performance. The contribution of this paper is to assess the improvement that is reached with a two-stage design method, concerning the transmission performance of a planar square loop relative to an initial design, without compromise to a Q-factor constraint. The first stage of the synthesis flow is analytical in approach, and determines the number and spacing of turns by which coupling between similar paired square loops can be enhanced with low deviation from the Q-factor limit presented by an initial design. The second stage applies full-wave electromagnetic simulations to determine more appropriate turn spacing and widths to match the Q-factor constraint, and achieve improved coupling relative to the initial design. Evaluating the design method in a test scenario yielded a more than 5% increase in link transmission efficiency, as well as an improvement in the link fractional bandwidth by more than 3%, without violating the loop Q-factor limit. These transmission performance enhancements are indicative of a potential for modifying proximity HF-RFID reader antennas for efficient inductive energy transfer and data telemetry links.

An approach to calculating metal particle detection in lubrication oil based on a micro inductive sensor

NASA Astrophysics Data System (ADS)

Wu, Yu; Zhang, Hongpeng

2017-12-01

A new microfluidic chip is presented to enhance the sensitivity of a micro inductive sensor, and an approach to coil inductance change calculation is introduced for metal particle detection in lubrication oil. Electromagnetic knowledge is used to establish a mathematical model of an inductive sensor for metal particle detection, and the analytic expression of coil inductance change is obtained by a magnetic vector potential. Experimental verification is carried out. The results show that copper particles 50-52 µm in diameter have been detected; the relative errors between the theoretical and experimental values are 7.68% and 10.02% at particle diameters of 108-110 µm and 50-52 µm, respectively. The approach presented here can provide a theoretical basis for an inductive sensor in metal particle detection in oil and other areas of application.

Low-Cost HTS Based Magnet System with an Inductively Coupled Pulsed Energy Extraction Protection System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agustsson, Ronald

In this project, RadiaBeam Technologies was tasked with developing a novel solution for a cost effective quench protection based on fast expansion of the normal zone. By inductively coupling a strong electromagnetic pulse via a resonant LC circuit, we attempted to demonstrate accelerated normal zone propagation. The AC field induces currents in the superconducting layer with the current density exceeding that of the critical current density, J c. This creates a large normal zone, uniformly distributing the dissipation through the magnet body. The method does not rely on thermal heating of the conductor, thus enabling nearly instantaneous protection. Through themore » course of the Phase II project, RadiaBeam Technologies continued extensive numerical modeling of the inductive quench system, re-designed and built several iterations of the POC system for testing and observed evidence of a transient partial quench being induced. However the final device was not fabricated. This was a consequence of the fundamentally complex nature of the energy extraction process and the challenges associated even with demonstrating the proof of concept in a bench top device.« less

Interpretation of deep directional resistivity measurements acquired in high-angle and horizontal wells using 3-D inversion

NASA Astrophysics Data System (ADS)

Puzyrev, Vladimir; Torres-Verdín, Carlos; Calo, Victor

2018-05-01

The interpretation of resistivity measurements acquired in high-angle and horizontal wells is a critical technical problem in formation evaluation. We develop an efficient parallel 3-D inversion method to estimate the spatial distribution of electrical resistivity in the neighbourhood of a well from deep directional electromagnetic induction measurements. The methodology places no restriction on the spatial distribution of the electrical resistivity around arbitrary well trajectories. The fast forward modelling of triaxial induction measurements performed with multiple transmitter-receiver configurations employs a parallel direct solver. The inversion uses a pre-conditioned gradient-based method whose accuracy is improved using the Wolfe conditions to estimate optimal step lengths at each iteration. The large transmitter-receiver offsets, used in the latest generation of commercial directional resistivity tools, improve the depth of investigation to over 30 m from the wellbore. Several challenging synthetic examples confirm the feasibility of the full 3-D inversion-based interpretations for these distances, hence enabling the integration of resistivity measurements with seismic amplitude data to improve the forecast of the petrophysical and fluid properties. Employing parallel direct solvers for the triaxial induction problems allows for large reductions in computational effort, thereby opening the possibility to invert multiposition 3-D data in practical CPU times.

Metallurgical technologies, energy conversion, and magnetohydrodynamic flows

NASA Astrophysics Data System (ADS)

Branover, Herman; Unger, Yeshajahu

The present volume discusses metallurgical applications of MHD, R&D on MHD devices employing liquid working medium for process applications, electromagnetic (EM) modulation of molten metal flow, EM pump performance of superconducting MHD devices, induction EM alkali-metal pumps, a physical model for EM-driven flow in channel-induction furnaces, grain refinement in Al alloys via EM vibrational method, dendrite growth of solidifying metal in dc magnetic field, MHD for mass and heat transfer in single-crystal melt growth, inverse EM shaping, and liquid-metal MHD development in Israel. Also discussed are the embrittlement of steel by lead, an open cycle MHD disk generator, the acceleration of gas-liquid piston flows for molten-metal MHD generators, MHD flow around a cylinder, new MHD drag coefficients, liquid-metal MHD two-phase flow, and two-phase liquid gas mixers for MHD energy conversion. (No individual items are abstracted in this volume)

Analysis of the impact of modification of cold crucible design on the efficiency of the cold crucible induction furnace

NASA Astrophysics Data System (ADS)

Przylucki, R.; Golak, S.; Bulinski, P.; Smolka, J.; Palacz, M.; Siwiec, G.; Lipart, J.; Blacha, L.

2018-05-01

The article includes numerical simulation results for two induction furnace with cold crucible (IFCC). Induction furnaces differ in cold crucible design, while the inductor geometry was preserved for both variants. Numerical simulations were conducted as three dimensional one, with coupled analysis of electromagnetic, thermal and fluid dynamics fields. During the experiment, six calculation variants, differ in amount of molten titanium (three different weights of titanium for each type of cold crucible) were considered. Main parameters controlled during the calculations were: electrical efficiency of the IFCC and the meniscus shape of liquid metal.

Electromagnetic induction imaging with a radio-frequency atomic magnetometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deans, Cameron; Marmugi, Luca, E-mail: l.marmugi@ucl.ac.uk; Hussain, Sarah

2016-03-07

We report on a compact, tunable, and scalable to large arrays imaging device, based on a radio-frequency optically pumped atomic magnetometer operating in magnetic induction tomography modality. Imaging of conductive objects is performed at room temperature, in an unshielded environment and without background subtraction. Conductivity maps of target objects exhibit not only excellent performance in terms of shape reconstruction but also demonstrate detection of sub-millimetric cracks and penetration of conductive barriers. The results presented here demonstrate the potential of a future generation of imaging instruments, which combine magnetic induction tomography and the unmatched performance of atomic magnetometers.

Application of advanced geophysical logging methods in the characterization of a fractured-sedimentary bedrock aquifer, Ventura County, California

USGS Publications Warehouse

Williams, John H.; Lane, John W.; Singha, Kamini; Haeni, F. Peter

2002-01-01

An integrated suite of advanced geophysical logging methods was used to characterize the geology and hydrology of three boreholes completed in fractured-sedimentary bedrock in Ventura County, California. The geophysical methods included caliper, gamma, electromagnetic induction, borehole deviation, optical and acoustic televiewer, borehole radar, fluid resistivity, temperature, and electromagnetic flowmeter. The geophysical logging 1) provided insights useful for the overall geohydrologic characterization of the bedrock and 2) enhanced the value of information collected by other methods from the boreholes including core-sample analysis, multiple-level monitoring, and packer testing.The logged boreholes, which have open intervals of 100 to 200 feet, penetrate a sequence of interbedded sandstone and mudstone with bedding striking 220 to 250 degrees and dipping 15 to 40 degrees to the northwest. Fractures intersected by the boreholes include fractures parallel to bedding and fractures with variable strike that dip moderately to steeply. Two to three flow zones were detected in each borehole. The flow zones consist of bedding-parallel or steeply dipping fractures or a combination of bedding-parallel fractures and moderately to steeply dipping fractures. About 75 to more than 90 percent of the measured flow under pumped conditions was produced by only one of the flow zones in each borehole.

Report for the MPV Demonstration at New Boston Air Force Base, New Hampshire: UXO Characterization in Challenging Survey Environments Using the MPV

DTIC Science & Technology

2017-04-28

EM Electromagnetic EMI Electromagnetic Induction ERDC Engineering Research and Development Center ESTCP Environmental Security Technology... bombs , HE bombs and incendiary bombs . The site hosted demonstrations with the MPV and the 2x2 TEMTADS, both with crews from CH2MHill. Each study...array of five receiver units that measure all three components of the EM field (Figure 2). This second-generation MPV is specifically designed to

Applicator modeling for electromagnetic thermotherapy of cervix cancer.

PubMed

Rezaeealam, Behrooz

2015-03-01

This report proposes an induction heating coil design that can be used for producing strong magnetic fields around ferromagnetic implants located in the cervix of uterus. The effect of coil design on the uniformity and extent of heat generation ability is inspected. Also, a numerical model of the applicator is developed that includes the ferromagnetic implants, and is coupled to the bioheat transfer model of the body tissue. Then, the ability of the proposed applicator for electromagnetic thermotherapy is investigated.

An AC-electromagnetic bearing for flywheel energy storage in space

NASA Technical Reports Server (NTRS)

Nikolajsen, Jorgen L.

1993-01-01

A repulsive type AC-electromagnetic bearing was developed and tested. It was conceived on the basis of the so-called Magnetic River suspension for high-speed trains. The appearance of the bearing is similar to the traditional DC-type electromagnetic bearing but the operating principle is different. The magnets are fed with alternating current instead of direct current and the rotor is fitted with a conducting sleeve (e.g. aluminum) instead of a ferromagnetic sleeve. The repulsion is due to induction of eddy-currents in the conducting sleeve. The bearing is inherently stable and requires no feedback control. It provides support in five degrees of freedom such that a short rotor may be fully supported by a single bearing. These capabilities were demonstrated experimentally. On the down side, the load carrying capacity and the damping obtained so far were quite low compared to the DC-type bearing. Also, significant heating of the conducting sleeve was experienced. The AC-bearing is essentially a modified induction motor and there are strong indications that it can be run both as a motor and as a generator with no commutator requirements. It is therefore considered to be a good candidate for support of energy storage flywheels in space.

Vertical Soil Profiling Using a Galvanic Contact Resistivity Scanning Approach

PubMed Central

Pan, Luan; Adamchuk, Viacheslav I.; Prasher, Shiv; Gebbers, Robin; Taylor, Richard S.; Dabas, Michel

2014-01-01

Proximal sensing of soil electromagnetic properties is widely used to map spatial land heterogeneity. The mapping instruments use galvanic contact, capacitive coupling or electromagnetic induction. Regardless of the type of instrument, the geometrical configuration between signal transmitting and receiving elements typically defines the shape of the depth response function. To assess vertical soil profiles, many modern instruments use multiple transmitter-receiver pairs. Alternatively, vertical electrical sounding can be used to measure changes in apparent soil electrical conductivity with depth at a specific location. This paper examines the possibility for the assessment of soil profiles using a dynamic surface galvanic contact resistivity scanning approach, with transmitting and receiving electrodes configured in an equatorial dipole-dipole array. An automated scanner system was developed and tested in agricultural fields with different soil profiles. While operating in the field, the distance between current injecting and measuring pairs of rolling electrodes was varied continuously from 40 to 190 cm. The preliminary evaluation included a comparison of scan results from 20 locations to shallow (less than 1.2 m deep) soil profiles and to a two-layer soil profile model defined using an electromagnetic induction instrument. PMID:25057135

A Review of High-Performance Computational Strategies for Modeling and Imaging of Electromagnetic Induction Data

NASA Astrophysics Data System (ADS)

Newman, Gregory A.

2014-01-01

Many geoscientific applications exploit electrostatic and electromagnetic fields to interrogate and map subsurface electrical resistivity—an important geophysical attribute for characterizing mineral, energy, and water resources. In complex three-dimensional geologies, where many of these resources remain to be found, resistivity mapping requires large-scale modeling and imaging capabilities, as well as the ability to treat significant data volumes, which can easily overwhelm single-core and modest multicore computing hardware. To treat such problems requires large-scale parallel computational resources, necessary for reducing the time to solution to a time frame acceptable to the exploration process. The recognition that significant parallel computing processes must be brought to bear on these problems gives rise to choices that must be made in parallel computing hardware and software. In this review, some of these choices are presented, along with the resulting trade-offs. We also discuss future trends in high-performance computing and the anticipated impact on electromagnetic (EM) geophysics. Topics discussed in this review article include a survey of parallel computing platforms, graphics processing units to multicore CPUs with a fast interconnect, along with effective parallel solvers and associated solver libraries effective for inductive EM modeling and imaging.

The Noise Level Optimization for Induction Magnetometer of SEP System

NASA Astrophysics Data System (ADS)

Zhu, W.; Fang, G.

2011-12-01

The Surface Electromagnetic Penetration (SEP) System, subsidized by the SinoProbe Plan in China, is designed for 3D conductivity imaging in geophysical mineral exploration, underground water distribution exploration, oil and gas reservoir exploration. Both the Controlled Source Audio Magnetotellurics (CSAMT) method and Magnetotellurics (MT) method can be surveyed by SEP system. In this article, an optimization design is introduced, which can minimize the noise level of the induction magnetometer for SEP system magnetic field's acquisition. The induction magnetometer transfers the rate of the magnetic field's change to voltage signal by induction coil, and amplified it by Low Noise Amplifier The noise parts contributed to the magnetometer are: the coil's thermal noise, the equivalent input voltage and current noise of the pre-amplifier. The coil's thermal noise is decided by coil's DC resistance. The equivalent input voltage and current noise of the pre-amplifier depend on the amplifier's type and DC operation condition. The design here optimized the DC operation point of pre-amplifier, adjusted the DC current source, and realized the minimum of total noise level of magnetometer. The calculation and test results show that: the total noise is about 1pT/√Hz, the thermal noise of coils is 1.7nV/√Hz, the preamplifier equivalent input voltage and current noise is 3nV/ √Hz and 0.1pA/√Hz, the weight of the magnetometer is 4.5kg and meet the requirement of SEP system.

The electromagnetic force field, fluid flow field and temperature profiles in levitated metal droplets

NASA Technical Reports Server (NTRS)

El-Kaddah, N.; Szekely, J.

1982-01-01

A mathematical representation was developed for the electromagnetic force field, the flow field, the temperature field (and for transport controlled kinetics), in a levitation melted metal droplet. The technique of mutual inductances was employed for the calculation of the electromagnetic force field, while the turbulent Navier - Stokes equations and the turbulent convective transport equations were used to represent the fluid flow field, the temperature field and the concentration field. The governing differential equations, written in spherical coordinates, were solved numerically. The computed results were in good agreement with measurements, regarding the lifting force, and the average temperature of the specimen and carburization rates, which were transport controlled.

Electromagnetic flat sheet forming by spiral type actuator coil

NASA Astrophysics Data System (ADS)

Akbar, S.; Aleem, M. A.; Sarwar, M. N.; Zillohu, A. U.; Awan, M. S.; Haider, A.; Ahmad, Z.; Akhtar, S.; Farooque, M.

2016-08-01

Focus of present work is to develop a setup for high strain rate electromagnetic forming of thin aluminum sheets (0.5, 1.0, 1.5 and 2.0 mm) and optimization of forming parameters. Flat spiral coil of 99.9% pure Cu strip (2.5x8.0 mm) with self-inductance 11 μH, 13 no. of turns and resultant outer diameter of 130mm has been fabricated and was coupled to a capacitor bank of energy, voltage and capacitance of 9 kJ, 900 V and 22.8 mF, respectively. To optimize the coil design, a commercially available software FEMM-4.2 was used to simulate the electromagnetic field profile generated by the coils of different pitch but same number of turns. Results of electromagnetic field intensity proposed by simulation agree in close proximity with those of theoretical as well as experimental data. The calculation of electromagnetic force and magnetic couplings between the coil and metal sheet are made. Forming parameters were optimized for different sheet thicknesses. Electromagnetic field intensity's profile plays a principal role in forming of typical shapes and patterns in sheets.

Applicability of CHSST Maglev technology for U.S. urban transportation

DOT National Transportation Integrated Search

2003-06-01

This report discusses the Chubu HSST technology applicability to U.S. urban transportation. This low speed system based on the principle of electromagnetic levitation by attractive suspension and propulsion by vehicle mounted linear induction motors ...

Technical data on new engineering products

NASA Astrophysics Data System (ADS)

1985-02-01

New grades of permanently magnetic materials; automatic digital radiolocator; bench winder; analog induction gauge; programmable pulse generator; portable defibrillators; pipe welders; two-component electromagnetic log; sulphur content analyzer; peristaltic pumps; function generators; welding manipulator; and tonsiometer are described.

The experimental-theoretical model of the jet HF induction discharge of atmospheric pressure

NASA Astrophysics Data System (ADS)

Gainullin, R.; Kirpichnikov, A.

2017-11-01

The paper considers theexperimental-theoretical model devised to determine the regularities of the quasi-stationary electromagnetic field structure of the HFI discharge burning in the inductor of finite dimensions at atmospheric pressure.

Effect of inductive and capacitive coupling on the current–voltage characteristic and electromagnetic radiation from a system of Josephson junctions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rahmonov, I. R., E-mail: rahmonov@theor.jinr.ru, E-mail: ilhom-tj@inbox.ru; Shukrinov, Yu. M.; Atanasova, P. Kh.

We have studied the current–voltage characteristic of a system of long Josephson junctions taking into account the inductive and capacitive coupling. The dependence of the average time derivative of the phase difference on the bias current and spatiotemporal dependences of the phase difference and magnetic field in each junction are considered. The possibility of branching of the current–voltage characteristic in the region of zero field step, which is associated with different numbers of fluxons in individual Josephson junctions, is demonstrated. The current–voltage characteristic of the system of Josephson junctions is compared with the case of a single junction, and itmore » is shown that the observed branching is due to coupling between the junctions. The intensity of electromagnetic radiation associated with motion of fluxons is calculated, and the effect of coupling between junctions on the radiation power is analyzed.« less

Feasibility study of a swept frequency electromagnetic probe (SWEEP) using inductive coupling for the determination of subsurface conductivity of the earth and water prospecting in arid regions

NASA Technical Reports Server (NTRS)

Latorraca, G. A.; Bannister, L. H.

1974-01-01

Techniques developed for electromagnetic probing of the lunar interior, and techniques developed for the generation of high power audio frequencies were combined to make practical a magnetic inductive coupling system for the rapid measurement of ground conductivity profiles which are helpful when prospecting for the presence and quality of subsurface water. A system which involves the measurement of the direction, intensity, and time phase of the magnetic field observed near the surface of the earth at a distance from a horizontal coil energized so as to create a field that penetrates the earth was designed and studied to deduce the conductivity and stratification of the subsurface. Theoretical studies and a rudimentary experiment in an arid region showed that the approach is conceptually valid and that this geophysical prospecting technique can be developed for the economical exploration of subterranean water resources.

Urban soil exploration through multi-receiver electromagnetic induction and stepped-frequency ground penetrating radar.

PubMed

Van De Vijver, Ellen; Van Meirvenne, Marc; Vandenhaute, Laura; Delefortrie, Samuël; De Smedt, Philippe; Saey, Timothy; Seuntjens, Piet

2015-07-01

In environmental assessments, the characterization of urban soils relies heavily on invasive investigation, which is often insufficient to capture their full spatial heterogeneity. Non-invasive geophysical techniques enable rapid collection of high-resolution data and provide a cost-effective alternative to investigate soil in a spatially comprehensive way. This paper presents the results of combining multi-receiver electromagnetic induction and stepped-frequency ground penetrating radar to characterize a former garage site contaminated with petroleum hydrocarbons. The sensor combination showed the ability to identify and accurately locate building remains and a high-density soil layer, thus demonstrating the high potential to investigate anthropogenic disturbances of physical nature. In addition, a correspondence was found between an area of lower electrical conductivity and elevated concentrations of petroleum hydrocarbons, suggesting the potential to detect specific chemical disturbances. We conclude that the sensor combination provides valuable information for preliminary assessment of urban soils.

Consideration of some fundamental erosion processes encountered in hypervelocity electromagnetic propulsion

NASA Astrophysics Data System (ADS)

Buckingham, A. C.; Hawke, R. S.

1982-09-01

Experimental and theoretical research was conducted jointly at the Livermore and Los Alamos National laboratories on dc electromagnetic railgun Lorentz accelerators. Pellets weighing a few grams to tens of grams were launched at velocities up to better than 11 km/s. The research is addressed to attaining repeated launches of samples at hypervelocity in target impact experiments. In these experiments, shock-induced pressure in the tens of megabars range are obtained for high pressure equations of state research. Primary energy sources of the order of several hundred kJ to a MJ and induction currents of the order of 1 or more MA are necessary for these launches. Erosion and deformation of the conductor rails and the accelerated sample material are continuing problems. The beating, stress, and erosion resulting from simultaneous imposition of rail induction current, dense plasma (armature) interaction, current distribution, magnetic field stresses and projectile/rail contact friction are examined.

Magnetic Field, Force, and Inductance Computations for an Axially Symmetric Solenoid

NASA Technical Reports Server (NTRS)

Lane, John E.; Youngquist, Robert C.; Immer, Christopher D.; Simpson, James C.

2001-01-01

The pumping of liquid oxygen (LOX) by magnetic fields (B field), using an array of electromagnets, is a current topic of research and development at Kennedy Space Center, FL. Oxygen is paramagnetic so that LOX, like a ferrofluid, can be forced in the direction of a B field gradient. It is well known that liquid oxygen has a sufficient magnetic susceptibility that a strong magnetic gradient can lift it in the earth's gravitational field. It has been proposed that this phenomenon can be utilized in transporting (i.e., pumping) LOX not only on earth, but on Mars and in the weightlessness of space. In order to design and evaluate such a magnetic pumping system, it is essential to compute the magnetic and force fields, as well as inductance, of various types of electromagnets (solenoids). In this application, it is assumed that the solenoids are air wrapped, and that the current is essentially time independent.

An electromagnetic modulator based on electrically controllable metamaterial analogue to electromagnetically induced transparency.

PubMed

Fan, Yuancheng; Qiao, Tong; Zhang, Fuli; Fu, Quanhong; Dong, Jiajia; Kong, Botao; Li, Hongqiang

2017-01-16

Electromagnetically induced transparency (EIT) is a promising technology for the enhancement of light-matter interactions, and recent demonstrations of the EIT analogue realized in artificial micro-structured medium have remarkably reduced the extreme requirement for experimental observation of EIT spectrum. In this paper, we propose to electrically control the EIT-like spectrum in a metamaterial as an electromagnetic modulator. A diode acting as a tunable resistor is loaded in the gap of paired wires to inductively tune the magnetic resonance, which induces remarkable modulation on the EIT-like spectrum through the metamaterial sample. The experimental measurements confirmed that the prediction of electromagnetic modulation in three narrow bands on the EIT-like spectrum, and a modulation contrast of up to 31 dB was achieved on the transmission through the metamaterial. Our results may facilitate the study on active/dynamical technology in translational metamaterials, which connect extraordinary manipulations on the flow of light in metamaterials, e.g., the exotic EIT, and practical applications in industry.

Nondestructive corrosion detection in concrete through integrated heat induction and IR thermography

NASA Astrophysics Data System (ADS)

Kwon, Seung-Jun; Xue, Henry; Feng, Maria Q.; Baek, Seunghoon

2011-04-01

Steel corrosion in concrete is a main cause of deterioration and early failure of concrete structures. A novel integration of electromagnetic heat induction and infrared (IR) thermography is proposed for nondestructive detection of steel corrosion in concrete, by taking advantage of the difference in thermal characteristics of corroded and non-corroded steel. This paper focuses on experimental investigation of the concept. An inductive heater is developed to remotely heat the steel rebar from concrete surface, which is integrated with an IR camera. Bare rebar and concrete samples with different cover depths are prepared. Each concrete sample is embedded with a single steel rebar in the middle, resulting an identical cover depth from the front and the back surfaces, which enables heat induction from one surface and IR thermogrphay from the other simultaneously. The impressed current method is adopted to induce accelerated corrosion on the rebar. IR video images are recorded during both heating and cooling periods. The test results demonstrate a clear difference in thermal characteristics between corroded and non-corroded samples. The corroded samples show higher rates of heating and cooling as well as a higher peak IR intensity than those of the non-corroded samples. This study demonstrates a potential for nondestructive detection of rebar corrosion in concrete.

First Stage of a Highly Reliable Reusable Launch System

NASA Technical Reports Server (NTRS)

Kloesel, Kurt J.; Pickrel, Jonathan B.; Sayles, Emily L.; Wright, Michael; Marriott, Darin; Holland, Leo; Kuznetsov, Stephen

2009-01-01

Electromagnetic launch assist has the potential to provide a highly reliable reusable first stage to a space access system infrastructure at a lower overall cost. This paper explores the benefits of a smaller system that adds the advantages of a high specific impulse air-breathing stage and supersonic launch speeds. The method of virtual specific impulse is introduced as a tool to emphasize the gains afforded by launch assist. Analysis shows launch assist can provide a 278-s virtual specific impulse for a first-stage solid rocket. Additional trajectory analysis demonstrates that a system composed of a launch-assisted first-stage ramjet plus a bipropellant second stage can provide a 48-percent gross lift-off weight reduction versus an all-rocket system. The combination of high-speed linear induction motors and ramjets is identified, as the enabling technologies and benchtop prototypes are investigated. The high-speed response of a standard 60 Hz linear induction motor was tested with a pulse width modulated variable frequency drive to 150 Hz using a 10-lb load, achieving 150 mph. A 300-Hz stator-compensated linear induction motor was constructed and static-tested to 1900 lbf average. A matching ramjet design was developed for use on the 300-Hz linear induction motor.

Energy harvesting for the implantable biomedical devices: issues and challenges.

PubMed

Hannan, Mahammad A; Mutashar, Saad; Samad, Salina A; Hussain, Aini

2014-06-20

The development of implanted devices is essential because of their direct effect on the lives and safety of humanity. This paper presents the current issues and challenges related to all methods used to harvest energy for implantable biomedical devices. The advantages, disadvantages, and future trends of each method are discussed. The concept of harvesting energy from environmental sources and human body motion for implantable devices has gained a new relevance. In this review, the harvesting kinetic, electromagnetic, thermal and infrared radiant energies are discussed. Current issues and challenges related to the typical applications of these methods for energy harvesting are illustrated. Suggestions and discussion of the progress of research on implantable devices are also provided. This review is expected to increase research efforts to develop the battery-less implantable devices with reduced over hole size, low power, high efficiency, high data rate, and improved reliability and feasibility. Based on current literature, we believe that the inductive coupling link is the suitable method to be used to power the battery-less devices. Therefore, in this study, the power efficiency of the inductive coupling method is validated by MATLAB based on suggested values. By further researching and improvements, in the future the implantable and portable medical devices are expected to be free of batteries.

Energy harvesting for the implantable biomedical devices: issues and challenges

PubMed Central

2014-01-01

The development of implanted devices is essential because of their direct effect on the lives and safety of humanity. This paper presents the current issues and challenges related to all methods used to harvest energy for implantable biomedical devices. The advantages, disadvantages, and future trends of each method are discussed. The concept of harvesting energy from environmental sources and human body motion for implantable devices has gained a new relevance. In this review, the harvesting kinetic, electromagnetic, thermal and infrared radiant energies are discussed. Current issues and challenges related to the typical applications of these methods for energy harvesting are illustrated. Suggestions and discussion of the progress of research on implantable devices are also provided. This review is expected to increase research efforts to develop the battery-less implantable devices with reduced over hole size, low power, high efficiency, high data rate, and improved reliability and feasibility. Based on current literature, we believe that the inductive coupling link is the suitable method to be used to power the battery-less devices. Therefore, in this study, the power efficiency of the inductive coupling method is validated by MATLAB based on suggested values. By further researching and improvements, in the future the implantable and portable medical devices are expected to be free of batteries. PMID:24950601

Multiphysics analysis of liquid metal annular linear induction pumps: A project overview

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maidana, Carlos Omar; Nieminen, Juha E.

Liquid metal-cooled fission reactors are both moderated and cooled by a liquid metal solution. These reactors are typically very compact and they can be used in regular electric power production, for naval and space propulsion systems or in fission surface power systems for planetary exploration. The coupling between the electromagnetics and thermo-fluid mechanical phenomena observed in liquid metal thermo-magnetic systems for nuclear and space applications gives rise to complex engineering magnetohydrodynamics and numerical problems. It is known that electromagnetic pumps have a number of advantages over rotating mechanisms: absence of moving parts, low noise and vibration level, simplicity of flowmore » rate regulation, easy maintenance and so on. However, while developing annular linear induction pumps, we are faced with a significant problem of magnetohydrodynamic instability arising in the device. The complex flow behavior in this type of devices includes a time-varying Lorentz force and pressure pulsation due to the time-varying electromagnetic fields and the induced convective currents that originates from the liquid metal flow, leading to instability problems along the device geometry. The determinations of the geometry and electrical configuration of liquid metal thermo-magnetic devices give rise to a complex inverse magnetohydrodynamic field problem were techniques for global optimization should be used, magnetohydrodynamics instabilities understood –or quantified- and multiphysics models developed and analyzed. Lastly, we present a project overview as well as a few computational models developed to study liquid metal annular linear induction pumps using first principles and the a few results of our multi-physics analysis.« less

Multiphysics analysis of liquid metal annular linear induction pumps: A project overview

DOE PAGES

Maidana, Carlos Omar; Nieminen, Juha E.

2016-03-14

Liquid metal-cooled fission reactors are both moderated and cooled by a liquid metal solution. These reactors are typically very compact and they can be used in regular electric power production, for naval and space propulsion systems or in fission surface power systems for planetary exploration. The coupling between the electromagnetics and thermo-fluid mechanical phenomena observed in liquid metal thermo-magnetic systems for nuclear and space applications gives rise to complex engineering magnetohydrodynamics and numerical problems. It is known that electromagnetic pumps have a number of advantages over rotating mechanisms: absence of moving parts, low noise and vibration level, simplicity of flowmore » rate regulation, easy maintenance and so on. However, while developing annular linear induction pumps, we are faced with a significant problem of magnetohydrodynamic instability arising in the device. The complex flow behavior in this type of devices includes a time-varying Lorentz force and pressure pulsation due to the time-varying electromagnetic fields and the induced convective currents that originates from the liquid metal flow, leading to instability problems along the device geometry. The determinations of the geometry and electrical configuration of liquid metal thermo-magnetic devices give rise to a complex inverse magnetohydrodynamic field problem were techniques for global optimization should be used, magnetohydrodynamics instabilities understood –or quantified- and multiphysics models developed and analyzed. Lastly, we present a project overview as well as a few computational models developed to study liquid metal annular linear induction pumps using first principles and the a few results of our multi-physics analysis.« less

Energy Harvesting from the Stray Electromagnetic Field around the Electrical Power Cable for Smart Grid Applications

PubMed Central

2016-01-01

For wireless sensor node (WSN) applications, this paper presents the harvesting of energy from the stray electromagnetic field around an electrical power line. Inductive and capacitive types of electrodynamic energy harvesters are developed and reported. For the produced energy harvesters, solid core and split-core designs are adopted. The inductive energy harvester comprises a copper wound coil which is produced on a mild steel core. However, the capacitive prototypes comprise parallel, annular discs separated by Teflon spacers. Moreover, for the inductive energy harvesters' wound coil and core, the parametric analysis is also performed. A Teflon housing is incorporated to protect the energy harvester prototypes from the harsh environmental conditions. Among the inductive energy harvesters, prototype-5 has performed better than the other harvesters and produces a maximum rms voltage of 908 mV at the current level of 155 A in the power line. However, at the same current flow, the capacitive energy harvesters produce a maximum rms voltage of 180 mV. The alternating output of the prototype-5 is rectified, and a super capacitor (1 F, 5.5 V) and rechargeable battery (Nickel-Cadmium, 3.8 V) are charged with it. Moreover, with the utilization of a prototype-5, a self-powered wireless temperature sensing and monitoring system for an electrical transformer is also developed and successfully implemented. PMID:27579343

Energy Harvesting from the Stray Electromagnetic Field around the Electrical Power Cable for Smart Grid Applications.

PubMed

Khan, Farid Ullah

For wireless sensor node (WSN) applications, this paper presents the harvesting of energy from the stray electromagnetic field around an electrical power line. Inductive and capacitive types of electrodynamic energy harvesters are developed and reported. For the produced energy harvesters, solid core and split-core designs are adopted. The inductive energy harvester comprises a copper wound coil which is produced on a mild steel core. However, the capacitive prototypes comprise parallel, annular discs separated by Teflon spacers. Moreover, for the inductive energy harvesters' wound coil and core, the parametric analysis is also performed. A Teflon housing is incorporated to protect the energy harvester prototypes from the harsh environmental conditions. Among the inductive energy harvesters, prototype-5 has performed better than the other harvesters and produces a maximum rms voltage of 908 mV at the current level of 155 A in the power line. However, at the same current flow, the capacitive energy harvesters produce a maximum rms voltage of 180 mV. The alternating output of the prototype-5 is rectified, and a super capacitor (1 F, 5.5 V) and rechargeable battery (Nickel-Cadmium, 3.8 V) are charged with it. Moreover, with the utilization of a prototype-5, a self-powered wireless temperature sensing and monitoring system for an electrical transformer is also developed and successfully implemented.

Design and Development of Micro-Power Generating Device for Biomedical Applications of Lab-on-a-Disc.

PubMed

Joseph, Karunan; Ibrahim, Fatimah; Cho, Jongman; Thio, Tzer Hwai Gilbert; Al-Faqheri, Wisam; Madou, Marc

2015-01-01

The development of micro-power generators for centrifugal microfluidic discs enhances the platform as a green point-of-care diagnostic system and eliminates the need for attaching external peripherals to the disc. In this work, we present micro-power generators that harvest energy from the disc's rotational movement to power biomedical applications on the disc. To implement these ideas, we developed two types of micro-power generators using piezoelectric films and an electromagnetic induction system. The piezoelectric-based generator takes advantage of the film's vibration during the disc's rotational motion, whereas the electromagnetic induction-based generator operates on the principle of current generation in stacks of coil exposed to varying magnetic flux. We have successfully demonstrated that at the spinning speed of 800 revolutions per minute (RPM) the piezoelectric film-based generator is able to produce up to 24 microwatts using 6 sets of films and the magnetic induction-based generator is capable of producing up to 125 milliwatts using 6 stacks of coil. As a proof of concept, a custom made localized heating system was constructed to test the capability of the magnetic induction-based generator. The heating system was able to achieve a temperature of 58.62 °C at 2200 RPM. This development of lab-on-a-disc micro power generators preserves the portability standards and enhances the future biomedical applications of centrifugal microfluidic platforms.

Detecting Underground Mine Voids Using Complex Geophysical Techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaminski, V. F.; Harbert, W. P.; Hammack, R. W.

2006-12-01

In July 2006, the National Energy Technology Laboratory in collaboration with Department of Geology and Planetary Science, University of Pittsburgh conducted complex ground geophysical surveys of an area known to be underlain by shallow coal mines. Geophysical methods including electromagnetic induction, DC resistivity and seismic reflection were conducted. The purpose of these surveys was to: 1) verify underground mine voids based on a century-old mine map that showed subsurface mine workings georeferenced to match with present location of geophysical test-site located on the territory of Bruceton research center in Pittsburgh, PA, 2) deliniate mine workings that may be potentially filledmore » with electrically conductive water filtrate emerging from adjacent groundwater collectors and 3) establish an equipment calibration site for geophysical instruments. Data from electromagnetic and resistivity surveys were further processed and inverted using EM1DFM, EMIGMA or Earthimager 2D capablilities in order to generate conductivity/depth images. Anomaly maps were generated, that revealed the locations of potential mine openings.« less

NONDESTRUCTIVE TESTING (NDT) TECHNIQUES TO DETECT CONTAINED SUBSURFACE HAZARDOUS WASTE

EPA Science Inventory

The project involves the detection of buried containers with NDT (remote-sensing) techniques. Seventeen techniques were considered and four were ultimately decided upon. They were: electromagnetic induction (EMI); metal detection (MD); magnetometer (MAG); and ground penetrating r...

Electromagnetic connector

NASA Technical Reports Server (NTRS)

Gardner, W. C.

1973-01-01

Connector pair consists of two iron cores brought together a short distance from each other. Each core is wound with insulated wire. Ac signal is connected through the pair across the gap by magnetic induction. Device can be used underwater or in flammable atmosphere.

A Newtonian approach to extraordinarily strong negative refraction.

PubMed

Yoon, Hosang; Yeung, Kitty Y M; Umansky, Vladimir; Ham, Donhee

2012-08-02

Metamaterials with negative refractive indices can manipulate electromagnetic waves in unusual ways, and can be used to achieve, for example, sub-diffraction-limit focusing, the bending of light in the 'wrong' direction, and reversed Doppler and Cerenkov effects. These counterintuitive and technologically useful behaviours have spurred considerable efforts to synthesize a broad array of negative-index metamaterials with engineered electric, magnetic or optical properties. Here we demonstrate another route to negative refraction by exploiting the inertia of electrons in semiconductor two-dimensional electron gases, collectively accelerated by electromagnetic waves according to Newton's second law of motion, where this acceleration effect manifests as kinetic inductance. Using kinetic inductance to attain negative refraction was theoretically proposed for three-dimensional metallic nanoparticles and seen experimentally with surface plasmons on the surface of a three-dimensional metal. The two-dimensional electron gas that we use at cryogenic temperatures has a larger kinetic inductance than three-dimensional metals, leading to extraordinarily strong negative refraction at gigahertz frequencies, with an index as large as -700. This pronounced negative refractive index and the corresponding reduction in the effective wavelength opens a path to miniaturization in the science and technology of negative refraction.

Mass sensitivity studies for an inductively driven railgun

NASA Astrophysics Data System (ADS)

Scanlon, J. J., III; Young, A. F.

1991-01-01

Those areas which result in substantial system mass reductions for an HPG (homopolar generator) driven EML (electromagnetic launcher) are identified. Sensitivity studies are performed by varying launch mass, peak acceleration, launcher efficiency, inductance gradient, injection velocity, barrel mass per unit length, fuel tankage and pump estimates, and component energy and power densities. Two major contributors to the system mass are the allowed number of shots per barrel versus the number required for the mission, and the barrel length. The effects of component performance parameters, such as friction coefficient, injection velocity, ablation coefficient, rail resistivity, armature voltage, peak acceleration, and inductance gradient on these two areas, are addressed.

Results from Sandia National Laboratories/Lockheed Martin Electromagnetic Missile Launcher (EMML).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lockner, Thomas Ramsbeck; Skurdal, Ben; Gaigler, Randy

2005-05-01

Sandia national laboratories (SNL) and lockheed martin MS2 are designing an electromagnetic missile launcher (EMML) for naval applications. The EMML uses an induction coilgun topology with the requirement of launching a 3600 lb. missile up to a velocity of 40 m/s. To demonstrate the feasibility of the electromagnetic propulsion design, a demonstrator launcher was built that consists of approximately 10% of the propulsion coils needed for a tactical design. The demonstrator verified the design by launching a 1430 lb weighted sled to a height of 24 ft in mid-December 2004 (Figure 1). This paper provides the general launcher design, specificmore » pulsed power system component details, system operation, and demonstration results.« less

On the analysis of using 3-coil wireless power transfer system in retinal prosthesis.

PubMed

Bai, Shun; Skafidas, Stan

2014-01-01

Designing a wireless power transmission system(WPTS) using inductive coupling has been investigated extensively in the last decade. Depending on the different configurations of the coupling system, there have been various designing methods to optimise the power transmission efficiency based on the tuning circuitry, quality factor optimisation and geometrical configuration. Recently, a 3-coil WPTS was introduced in retinal prosthesis to overcome the low power transferring efficiency due to low coupling coefficient. Here we present a method to analyse this 3-coil WPTS using the S-parameters to directly obtain maximum achievable power transferring efficiency. Through electromagnetic simulation, we brought a question on the condition of improvement using 3-coil WPTS in powering retinal prosthesis.

Radiated interference in rapid transit systems. volume 2. suggested test procedures.

DOT National Transportation Integrated Search

1987-06-30

The purpose of this report is to present a suggested test procedure for measuring the radiated electromagnetic interference (EMI) emanating from rail transit systems. This report points out that, unlike inductive and conductive EMI, radiated EMI has ...

Low-frequency pulsed electromagnetic fields significantly improve time of closure and proliferation of human tendon fibroblasts

PubMed Central

2014-01-01

Background The promotion of the healing process following musculoskeletal injuries comprises growth factor signalling, migration, proliferation and apoptosis of cells. If these processes could be modulated, the healing of tendon tissue may be markedly enhanced. Here, we report the use of the Somagen™ device, which is certified for medical use according to European laws. It generates low-frequency pulsed electromagnetic fields that trigger effects of a nature that are yet to be determined. Methods A 1.5-cm wide, linear scrape was introduced into patellar tendon fibroblast cultures (N = 5 donors). Treatment was carried out every second day. The regimen was applied three times in total with 30 minutes comprising pulsed electromagnetic field packages with two fundamental frequencies (10 minutes of 33 Hz, 20 minutes of 7.8 Hz). Control cells remained untreated. All samples were analyzed for gap closure time, proliferation and apoptosis one week after induction of the scrape wound. Results The mean time for bridging the gap in the nontreated cells was 5.05 ± 0.33 days, and in treated cells, it took 3.35 ± 0.38 days (P <0.001). For cell cultures with scrape wounds, a mean value for BrdU incorporation of OD = 0.70 ± 0.16 was found. Whereas low-frequency pulsed electromagnetic fields treated samples showed OD = 1.58 ± 0.24 (P <0.001). However, the percentage of apoptotic cells did not differ between the two groups. Conclusions Our data demonstrate that low-frequency pulsed electromagnetic fields emitted by the Somagen™ device influences the in vitro wound healing of patellar tendon fibroblasts and, therefore, possibly increases wound healing potential. PMID:24996421

Electromagnetic studies of global geodynamic processes

NASA Astrophysics Data System (ADS)

Tarits, Pascal

1994-03-01

The deep electromagnetic sounding (DES) technique is one of the few geophysical methods, along with seismology, gravity, heat flow, which may be use to probe the structure of the Earth's mantle directly. The interpretation of the DESs may provide electrical conductivity profiles down to the upper part of the lower mantle. The electrical conductivity is extremely sensitive to most of the thermodynamic processes we believe are acting in the Earth's mantle (temperature increases, partial melting, phase transition and to a lesser extent pressure). Therefore, in principle, results from DES along with laboratory measurements could be used to constrain models of these processes. The DES technique is reviewed in the light of recent results obtained in a variety of domains: data acquisition and analysis, global induction modeling and data inversion and interpretation. The mechanisms and the importance of surface distortions of the DES data are reviewed and techniques to model them are discussed. The recent results in terms of the conductivity distribution in the mantle from local and global DES are presented and a tentative synthesis is proposed. The geodynamic interpretations of the deep conductivity structures are reviewed. The existence of mantle lateral heterogeneities in conductivity at all scales and depths for which electromagnetic data are available is now well documented. A comparison with global results from seismology is presented.

Weak low-frequency electromagnetic oscillations in water.

PubMed

Liboff, A R; Poggi, Claudio; Pratesi, Piero

2017-01-01

Recent observations of low-frequency electromagnetic oscillations in water suggest an inductive structural component. Accordingly, we assume a helical basis enabling us to model water as an LC tuned oscillator. A proposed tetrahedral structure consisting of three water molecules and one hydronium ion is incorporated into the Boerdijk-Coxeter tetrahelix to form long water chains that are shown to have resonance frequencies consistent with observation. This model also serves to explain separately reported claims of ion cyclotron resonance of hydronium ions, in that the tetrahelix provides a built-in path for helical proton-hopping.

Borehole-geophysical investigation of the University of Connecticut landfill, Storrs, Connecticut

USGS Publications Warehouse

Johnson, Carole D.; Haeni, F.P.; Lane, John W.; White, Eric A.

2002-01-01

A borehole-geophysical investigation was conducted to help characterize the hydrogeology of the fractured-rock aquifer and the distribution of unconsolidated glacial deposits near the former landfill and chemical waste-disposal pits at the University of Connecticut in Storrs, Connecticut. Eight bedrock boreholes near the landfill and three abandoned domestic wells located nearby were logged using conventional and advanced borehole-geophysical methods from June to October 1999. The conventional geophysical-logging methods included caliper, gamma, fluid temperature, fluid resistivity, and electromagnetic induction. The advanced methods included deviation, optical and acoustic imaging of the borehole wall, heat-pulse flowmeter, and directional radar reflection. Twenty-one shallow piezometers (less than 50-feet deep) were logged with gamma and electromagnetic induction tools to delineate unconsolidated glacial deposits. Five additional shallow bedrock wells were logged with conventional video camera, caliper, electromagnetic induction, and fluid resistivity and temperature tools. The rock type, foliation, and fracturing of the site were characterized from high-resolution optical-televiewer (OTV) images of rocks penetrated by the boreholes. The rocks are interpreted as fine- to medium-grained quartz-feldspar-biotite-garnet gneiss and schist with local intrusions of quartz diorite and pegmatite and minor concentrations of sulfide mineralization similar to rocks described as the Bigelow Brook Formation on regional geologic maps. Layers containing high concentrations of sulfide minerals appear as high electrical conductivity zones on electromagnetic-induction and borehole-radar logs. Foliation in the rocks generally strikes to the northeast-southwest and dips to the west, consistent with local outcrop observations. The orientation of foliation and small-scale gneissic layering in the rocks, however, varies locally and with depth in some of the boreholes. In two of the boreholes, the foliation strikes predominantly to the northwest and dips to the northeast. Although small-scale faults and lithologic discontinuities were observed in the OTV data, no large-scale faults were observed that appear on regional geologic maps. Fractures were located and characterized through the use of conventional geophysical, OTV, acoustic-televiewer (ATV), and borehole-radar logs. The orientation of fractures varies considerably across the site; some fractures are parallel to the foliation, whereas others cross-cut the foliation. Many of the transmissive fractures in the bedrock boreholes strike about N170?E and N320?E with dips of less than 45?. Other transmissive fractures strike about N60?E with dips of more than 60?. Most of the transmissive fractures in the domestic wells strike about N60?E and N22?E with dips of more than 45?. The strike of N60?E is parallel to the trend of a thrust fault that appears on regional geologic maps. Vertical flow in the boreholes was measured with the heat-pulse flowmeter under ambient and (or) pumping conditions. Results of ATV, OTV, and conventional logs were used to locate specific zones for flowmeter testing. Ambient downflow was measured in three boreholes, ambient upflow was measured in two other boreholes, and both ambient downflow and upflow were measured in a sixth borehole. The other five bedrock boreholes and domestic wells did not have measurable vertical flow. The highest rate of ambient flow was measured in the background borehole in which upflow and downflow converged and exited the borehole at a fracture zone near a depth of 62 feet. Ambient flow of about 340 gallons per day was measured. In the other five wells, ambient flow of about 20 to 35 gallons per day was measured. Under low-rate pumping (0.25 to 1 gallon per minute), one to six inflow zones were identified in each well. Usually the fractures that are active under ambient conditions contribute to the well under pumping conditions. To prevent

The History of Electromagnetic Induction Techniques in Soil Survey

NASA Astrophysics Data System (ADS)

Brevik, Eric C.; Doolittle, Jim

2014-05-01

Electromagnetic induction (EMI) has been used to characterize the spatial variability of soil properties since the late 1970s. Initially used to assess soil salinity, the use of EMI in soil studies has expanded to include: mapping soil types; characterizing soil water content and flow patterns; assessing variations in soil texture, compaction, organic matter content, and pH; and determining the depth to subsurface horizons, stratigraphic layers or bedrock, among other uses. In all cases the soil property being investigated must influence soil apparent electrical conductivity (ECa) either directly or indirectly for EMI techniques to be effective. An increasing number and diversity of EMI sensors have been developed in response to users' needs and the availability of allied technologies, which have greatly improved the functionality of these tools. EMI investigations provide several benefits for soil studies. The large amount of georeferenced data that can be rapidly and inexpensively collected with EMI provides more complete characterization of the spatial variations in soil properties than traditional sampling techniques. In addition, compared to traditional soil survey methods, EMI can more effectively characterize diffuse soil boundaries and identify included areas of dissimilar soils within mapped soil units, giving soil scientists greater confidence when collecting spatial soil information. EMI techniques do have limitations; results are site-specific and can vary depending on the complex interactions among multiple and variable soil properties. Despite this, EMI techniques are increasingly being used to investigate the spatial variability of soil properties at field and landscape scales.

Enhancement of mesenchymal stem cell chondrogenesis with short-term low intensity pulsed electromagnetic fields.

PubMed

Parate, Dinesh; Franco-Obregón, Alfredo; Fröhlich, Jürg; Beyer, Christian; Abbas, Azlina A; Kamarul, Tunku; Hui, James H P; Yang, Zheng

2017-08-25

Pulse electromagnetic fields (PEMFs) have been shown to recruit calcium-signaling cascades common to chondrogenesis. Here we document the effects of specified PEMF parameters over mesenchymal stem cells (MSC) chondrogenic differentiation. MSCs undergoing chondrogenesis are preferentially responsive to an electromagnetic efficacy window defined by field amplitude, duration and frequency of exposure. Contrary to conventional practice of administering prolonged and repetitive exposures to PEMFs, optimal chondrogenic outcome is achieved in response to brief (10 minutes), low intensity (2 mT) exposure to 6 ms bursts of magnetic pulses, at 15 Hz, administered only once at the onset of chondrogenic induction. By contrast, repeated exposures diminished chondrogenic outcome and could be attributed to calcium entry after the initial induction. Transient receptor potential (TRP) channels appear to mediate these aspects of PEMF stimulation, serving as a conduit for extracellular calcium. Preventing calcium entry during the repeated PEMF exposure with the co-administration of EGTA or TRP channel antagonists precluded the inhibition of differentiation. This study highlights the intricacies of calcium homeostasis during early chondrogenesis and the constraints that are placed on PEMF-based therapeutic strategies aimed at promoting MSC chondrogenesis. The demonstrated efficacy of our optimized PEMF regimens has clear clinical implications for future regenerative strategies for cartilage.

An electromagnetic induced transparency-like scheme for wireless power transfer using dielectric resonators

NASA Astrophysics Data System (ADS)

Elnaggar, Sameh Y.

2017-02-01

Similar to the hybridization of three atoms, three coupled resonators interact to form bonding, anti-bonding, and non-bonding modes. The non-bonding mode enables an electromagnetic induced transparency like transfer of energy. Here, the non-bonding mode, resulting from the strong electric coupling of two dielectric resonators and an enclosure, is exploited to show that it is feasible to transfer power over a distance comparable to the operating wavelength. In this scheme, the enclosure acts as a mediator. The strong coupling permits the excitation of the non-bonding mode with high purity. This approach is different from resonant inductive coupling, which works in the sub-wavelength regime. Optimal loads and the corresponding maximum efficiency are determined using two independent methods: Coupled Mode Theory and Circuit modelling. It is shown that, unlike resonant inductive coupling, the figure of merit depends on the enclosure quality and not on the load, which emphasizes the role of the enclosure as a mediator. Briefly after the input excitation is turned on, the energy in the receiver builds up via all coupled and spurious modes. As time elapses, all modes except the non-bonding cease to sustain. Due to the strong coupling between the dielectrics and the enclosure, such systems have unique properties such as high and uniform efficiency over large distances and minimal fringing fields. These properties suggest that electromagnetic induced transparency like schemes that rely on the use of dielectric resonators can be used to power autonomous systems inside an enclosure or find applications when exposure to the fields needs to be minimal. Finite Element computations are used to verify the theoretical predictions by determining the transfer efficiency, field profile, and coupling coefficients for two different systems. It is shown that the three resonators must be present for efficient power transfer; if one or more are removed, the transfer efficiency reduces significantly.

Terahertz electromagnetic fields (0.106 THz) do not induce manifest genomic damage in vitro.

PubMed

Hintzsche, Henning; Jastrow, Christian; Kleine-Ostmann, Thomas; Kärst, Uwe; Schrader, Thorsten; Stopper, Helga

2012-01-01

Terahertz electromagnetic fields are non-ionizing electromagnetic fields in the frequency range from 0.1 to 10 THz. Potential applications of these electromagnetic fields include the whole body scanners, which currently apply millimeter waves just below the terahertz range, but future scanners will use higher frequencies in the terahertz range. These and other applications will bring along human exposure to these fields. Up to now, only a limited number of investigations on biological effects of terahertz electromagnetic fields have been performed. Therefore, research is strongly needed to enable reliable risk assessment.Cells were exposed for 2 h, 8 h, and 24 h with different power intensities ranging from 0.04 mW/cm(2) to 2 mW/cm(2), representing levels below, at, and above current safety limits. Genomic damage on the chromosomal level was measured as micronucleus formation. DNA strand breaks and alkali-labile sites were quantified with the comet assay. No DNA strand breaks or alkali-labile sites were observed as a consequence of exposure to terahertz electromagnetic fields in the comet assay. The fields did not cause chromosomal damage in the form of micronucleus induction.

Terahertz Electromagnetic Fields (0.106 THz) Do Not Induce Manifest Genomic Damage In Vitro

PubMed Central

Hintzsche, Henning; Jastrow, Christian; Kleine-Ostmann, Thomas; Kärst, Uwe; Schrader, Thorsten; Stopper, Helga

2012-01-01

Terahertz electromagnetic fields are non-ionizing electromagnetic fields in the frequency range from 0.1 to 10 THz. Potential applications of these electromagnetic fields include the whole body scanners, which currently apply millimeter waves just below the terahertz range, but future scanners will use higher frequencies in the terahertz range. These and other applications will bring along human exposure to these fields. Up to now, only a limited number of investigations on biological effects of terahertz electromagnetic fields have been performed. Therefore, research is strongly needed to enable reliable risk assessment. Cells were exposed for 2 h, 8 h, and 24 h with different power intensities ranging from 0.04 mW/cm2 to 2 mW/cm2, representing levels below, at, and above current safety limits. Genomic damage on the chromosomal level was measured as micronucleus formation. DNA strand breaks and alkali-labile sites were quantified with the comet assay. No DNA strand breaks or alkali-labile sites were observed as a consequence of exposure to terahertz electromagnetic fields in the comet assay. The fields did not cause chromosomal damage in the form of micronucleus induction. PMID:23029508

Modulated wave formation in myocardial cells under electromagnetic radiation

NASA Astrophysics Data System (ADS)

Takembo, Clovis N.; Mvogo, A.; Ekobena Fouda, H. P.; Kofané, T. C.

2018-06-01

We exclusively analyze the onset and condition of formation of modulated waves in a diffusive FitzHugh-Nagumo model for myocardial cell excitations. The cells are connected through gap junction coupling. An additive magnetic flux variable is used to describe the effect of electromagnetic induction, while electromagnetic radiation is imposed on the magnetic flux variable as a periodic forcing. We used the discrete multiple scale expansion and obtained, from the model equations, a single differential-difference amplitude nonlinear equation. We performed the linear stability analysis of this equation and found that instability features are importantly influenced by the induced electromagnetic gain. We present the unstable and stable regions of modulational instability (MI). The resulting analytic predictions are confirmed by numerical experiments of the generic equations. The results reveal that due to MI, an initial steady state that consisted of a plane wave with low amplitude evolves into a modulated localized wave patterns, soliton-like in shape, with features of synchronization. Furthermore, the formation of periodic pulse train with breathing motion presents a disappearing pattern in the presence of electromagnetic radiation. This could provide guidance and better understanding of sudden heart failure exposed to heavily electromagnetic radiation.

Design optimization of high frequency transformer with controlled leakage inductance for current fed dual active bridge converter

NASA Astrophysics Data System (ADS)

Jung, Tae-Uk; Kim, Myung-Hwan; Yoo, Jin-Hyung

2018-05-01

Current fed dual active bridge converters for photovoltaic generation may typically require a given leakage or extra inductance in order to provide proper control of the currents. Therefore, the many researches have been focused on the leakage inductance control of high frequency transformer to integrate an extra inductor. In this paper, an asymmetric winding arrangement to get the controlled leakage inductance for the high frequency transformer is proposed to improve the efficiency of the current fed dual active bridge converter. In order to accurate analysis, a coupled electromagnetic analysis model of transformer connected with high frequency switching circuit is used. A design optimization procedure for high efficiency is also presented using design analysis model, and it is verified by the experimental result.

Experimental observation of the inductive electric field and related plasma nonuniformity in high frequency capacitive discharge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahn, S. K.; Chang, H. Y.

To elucidate plasma nonuniformity in high frequency capacitive discharges, Langmuir probe and B-dot probe measurements were carried out in the radial direction in a cylindrical capacitive discharge driven at 90 MHz with argon pressures of 50 and 400 mTorr. Through the measurements, a significant inductive electric field (i.e., time-varying magnetic field) was observed at the radial edge, and it was found that the inductive electric field creates strong plasma nonuniformity at high pressure operation. The plasma nonuniformity at high pressure operation is physically similar to the E-H mode transition typically observed in inductive discharges. This result agrees well with themore » theories of electromagnetic effects in large area and/or high frequency capacitive discharges.« less

Welding quality evaluation of resistance spot welding using the time-varying inductive reactance signal

NASA Astrophysics Data System (ADS)

Zhang, Hongjie; Hou, Yanyan; Yang, Tao; Zhang, Qian; Zhao, Jian

2018-05-01

In the spot welding process, a high alternating current is applied, resulting in a time-varying electromagnetic field surrounding the welder. When measuring the welding voltage signal, the impedance of the measuring circuit consists of two parts: dynamic resistance relating to weld nugget nucleation event and inductive reactance caused by mutual inductance. The aim of this study is to develop a method to acquire the dynamic reactance signal and to discuss the possibility of using this signal to evaluate the weld quality. For this purpose, a series of experiments were carried out. The reactance signals under different welding conditions were compared and the results showed that the morphological feature of the reactance signal was closely related to the welding current and it was also significantly influenced by some abnormal welding conditions. Some features were extracted from the reactance signal and combined to construct weld nugget strength and diameter prediction models based on the radial basis function (RBF) neural network. In addition, several features were also used to monitor the expulsion in the welding process by using Fisher linear discriminant analysis. The results indicated that using the dynamic reactance signal to evaluate weld quality is possible and feasible.

Design and analysis of a flux intensifying permanent magnet embedded salient pole wind generator

NASA Astrophysics Data System (ADS)

Guo, Yujing; Jin, Ping; Lin, Heyun; Yang, Hui; Lyu, Shukang

2018-05-01

This paper presents an improved flux intensifying permanent magnet embedded salient pole wind generator (FI-PMESPWG) with mirror symmetrical magnetizing directions permanent magnet (PM) for improving generator's performances. The air-gap flux densities, the output voltage, the cogging torque and the d- and q-axis inductances of FI-PMESPWG are all calculated and analyzed by using the finite element method (FEM). To highlight the advantages of the proposed FI-PMESPWG, an original permanent magnet embedded salient pole wind generator (PMESPWG) model is adopted for comparison under the same operating conditions. The calculating results show that the air-gap flux densities of FI-PMESPWG are intensified with the same magnet amounts because the PMs are set in a form of V shape in each pole. The difference between d-axis inductance and q-axis inductance of the proposed FI-PMESPWG is reduced. Thus, the output power of the proposed FI-PMESPWG reaches a higher value than that of the original PMESPWG at the same current phase angle. The cogging torque is diminished because the flux path is changed. All the analysis results indicate that the electromagnetic characteristics of the proposed FI-PMESPWG are significantly better than that of the original PMESPWG.

Improvement in magnetic field immunity of externally-coupled transcutaneous energy transmission system for a totally implantable artificial heart.

PubMed

Yamamoto, Takahiko; Koshiji, Kohji; Homma, Akihiko; Tatsumi, Eisuke; Taenaka, Yoshiyuki

2008-01-01

Transcutaneous energy transmission (TET) that uses electromagnetic induction between the external and internal coils of a transformer is the most promising method to supply driving energy to a totally implantable artificial heart without invasion. Induction-heating (IH) cookers generate magnetic flux, and if a cooker is operated near a transcutaneous transformer, the magnetic flux generated will link with the external and internal coils of the transcutaneous transformer. This will affect the performance of the TET and the artificial heart system. Hence, it is necessary to improve the magnetic field immunity of the TET system. During operation of the system, if the transcutaneous transformer is in close proximity to an IH cooker, the electric power generated by the cooker and coupled to the transformer can drive the artificial heart system. To prevent this coupling, the external coil was shielded with a conductive shield that had a slit in it. This reduces the coupling between the transformer and the magnetic field generated by the induction cooker. However, the temperature of the shield increased due to heating by eddy currents. The temperature of the shield can be reduced by separating the IH cooker and the shield.

Advanced electric motor technology flux mapping

NASA Technical Reports Server (NTRS)

Doane, George B., III; Campbell, Warren; Dean, Garvin

1993-01-01

Design of electric motors which fulfill the needs of Thrust Vector Control (TVC) actuators used in large rocket propelled launch vehicles is covered. To accomplish this end the methodology of design is laid out in some detail. In addition a point design of a motor to fulfill the requirements of a certain actuator specified by MSFC is accomplished and reported upon. In the course of this design great stress has been placed on ridding the actuator of internally generated heat. To conduct the heat out of the motor use is made of the unique properties of the in house MSFC designed driving electronics. This property is that as along as they are operated in a quasi-linear mode the electronics nullify the effects of armature inductance as far as the phase of the armature current versus the rotor position is concerned. Actually the additional inductance due to the extended end turns in this design is of benefit because in the shorted armature failure mode the armature current in the fault (caused by the rotor flux sweeping past the armature) is diminished at a given rotor speed when compared to a more conventional motor with lower inductance. The magnetic circuit is analyzed using electromagnetic finite element methods.

Experiments with a Differential Transformer

ERIC Educational Resources Information Center

Aguilar, Horacio Munguía

2016-01-01

An experiment with an electric transformer based on single coils shows how electromagnetic induction changes when the magnetic coupling between coils is adjusted. This transformer has two secondary outputs which are taken differentially. This is the basis for a widely used position transducer known as LVDT.

Electromagnetic Induction E-Sensor for Underwater UXO Detection

DTIC Science & Technology

2011-12-01

EMF Electromotive force FET Field Effect Transitor Hz Hertz ms millisecond nV nanoVolt QFS QUASAR Federal...processing. Statistical discrimination techniques based on model analysis, such as the Time-Domain Three Dipole (TD3D) model, can separate UXO-like objects

Hybridizing triboelectrification and electromagnetic induction effects for high-efficient mechanical energy harvesting.

PubMed

Hu, Youfan; Yang, Jin; Niu, Simiao; Wu, Wenzhuo; Wang, Zhong Lin

2014-07-22

The recently introduced triboelectric nanogenerator (TENG) and the traditional electromagnetic induction generator (EMIG) are coherently integrated in one structure for energy harvesting and vibration sensing/isolation. The suspended structure is based on two oppositely oriented magnets that are enclosed by hollow cubes surrounded with coils, which oscillates in response to external disturbance and harvests mechanical energy simultaneously from triboelectrification and electromagnetic induction. It extends the previous definition of hybrid cell to harvest the same type of energy with multiple approaches. Both the sliding-mode TENG and contact-mode TENG can be achieved in the same structure. In order to make the TENG and EMIG work together, transformers are used to match the output impedance between these two power sources with very different characteristics. The maximum output power of 7.7 and 1.9 mW on the same load of 5 kΩ was obtained for the TENG and EMIG, respectively, after impedance matching. Benefiting from the rational design, the output signal from the TENG and the EMIG are in phase. They can be added up directly to get an output voltage of 4.6 V and an output current of 2.2 mA in parallel connection. A power management circuit was connected to the hybrid cell, and a regulated voltage of 3.3 V with constant current was achieved. For the first time, a logic operation was carried out on a half-adder circuit by using the hybrid cell working as both the power source and the input digit signals. We also demonstrated that the hybrid cell can serve as a vibration isolator. Further applications as vibration dampers, triggers, and sensors are all promising.

Design and Development of Micro-Power Generating Device for Biomedical Applications of Lab-on-a-Disc

PubMed Central

Joseph, Karunan; Ibrahim, Fatimah; Cho, Jongman; Thio, Tzer Hwai Gilbert; Al-Faqheri, Wisam; Madou, Marc

2015-01-01

The development of micro-power generators for centrifugal microfluidic discs enhances the platform as a green point-of-care diagnostic system and eliminates the need for attaching external peripherals to the disc. In this work, we present micro-power generators that harvest energy from the disc’s rotational movement to power biomedical applications on the disc. To implement these ideas, we developed two types of micro-power generators using piezoelectric films and an electromagnetic induction system. The piezoelectric-based generator takes advantage of the film’s vibration during the disc’s rotational motion, whereas the electromagnetic induction-based generator operates on the principle of current generation in stacks of coil exposed to varying magnetic flux. We have successfully demonstrated that at the spinning speed of 800 revolutions per minute (RPM) the piezoelectric film-based generator is able to produce up to 24 microwatts using 6 sets of films and the magnetic induction-based generator is capable of producing up to 125 milliwatts using 6 stacks of coil. As a proof of concept, a custom made localized heating system was constructed to test the capability of the magnetic induction-based generator. The heating system was able to achieve a temperature of 58.62°C at 2200 RPM. This development of lab-on-a-disc micro power generators preserves the portability standards and enhances the future biomedical applications of centrifugal microfluidic platforms. PMID:26422249

Low-frequency electrical dosimetry: research agenda of the IEEE International Committee on Electromagnetic Safety.

PubMed

Reilly, J Patrick; Hirata, Akimasa

2016-06-21

This article treats unsettled issues in the use of numerical models of electrical dosimetry as applied to international limits on human exposure to low-frequency (typically  <  100 kHz) electromagnetic fields and contact current. The perspective in this publication is that of Subcommittee 6 of IEEE-ICES (International Committee on Electromagnetic Safety) Technical Committee 95. The paper discusses 25 issues needing attention, fitting into three general categories: induction models; electrostimulation models; and human exposure limits. Of these, 9 were voted as 'high priority' by members of Subcommittee 6. The list is presented as a research agenda for refinements in numerical modeling with applications to human exposure limits. It is likely that such issues are also important in medical and electrical product safety design applications.

Effect of bird maneuver on frequency-domain helicopter EM response

USGS Publications Warehouse

Fitterman, D.V.; Yin, C.

2004-01-01

Bird maneuver, the rotation of the coil-carrying instrument pod used for frequency-domain helicopter electromagnetic surveys, changes the nominal geometric relationship between the bird-coil system and the ground. These changes affect electromagnetic coupling and can introduce errors in helicopter electromagnetic, (HEM) data. We analyze these effects for a layered half-space for three coil configurations: vertical coaxial, vertical coplanar, and horizontal coplanar. Maneuver effect is shown to have two components: one that is purely geometric and another that is inductive in nature. The geometric component is significantly larger. A correction procedure is developed using an iterative approach that uses standard HEM inversion routines. The maneuver effect correction reduces inversion misfit error and produces laterally smoother cross sections than obtained from uncorrected data. ?? 2004 Society of Exploration Geophysicists. All rights reserved.

The ringer - An efficient, high repetition rate circuit for electromagnetic launchers

NASA Astrophysics Data System (ADS)

Giorgi, D.; Helava, H.; Lindner, K.; Long, J.; Zucker, O.

1989-01-01

The Meatgrinder is an efficient, current-multiplying circuit which can be used to optimize the energy transfer to various electromagnetic gun configurations. The authors present a simple variant of the Meatgrinder circuit which permits a first-order current profiling into the gun and recovery of the inductive energy in the barrel at a high repetition rate. The circuit is basically a one-stage Meatgrinder which utilizes the ringing of the energy storage capacitor (less than 40 percent reversal) to perform the opening switch function and a solid-state diode as the crowbar switch between the two mutually coupled inductors. With resonant charging, this results in a completely passive, high-repetiton-rate electromagnetic-gun power supply. Since most of the barrel energy is recovered, a railgun with negligible muzzle flash can be realized.

An Electromagnetic Induction Flashlight Experiment

ERIC Educational Resources Information Center

Alden, Emily; Kennedy, Mark; Lorenzon, Wolfgang; Smith, Warren

2007-01-01

In the last several years, the electronics industry has released hand generator-powered flashlights, which are advertised as the end of battery-powered flashlights. This has become possible because of recent advances in capacitor, magnet, and LED technology. Nevertheless, the physics behind these flashlights is fairly simple.

Electromagnetic Induction

ERIC Educational Resources Information Center

Yochum, Hank; Vinion-Dubiel, Arlene; Granger, Jill; Lindsay, Lynne; Maass, Teresa; Mayhew, Sarah

2013-01-01

Engaging children in authentic investigation opens the doors for them to gain deep conceptual understanding in science. As students engage in investigation, they experience the practices employed by scientists and engineers, as highlighted in the Next Generation Science Standards (Achieve Inc. 2013). They also begin to understand the nature of…

Simplified spatiotemporal electromagnetic induction - salinity multi-field calibration

USDA-ARS?s Scientific Manuscript database

Salinity-affected farmlands are common in arid and semi-arid regions. To assure long-term sustainability of farming practices in these areas, soil salinity (ECe) should be routinely mapped and monitored. Salinity can be measured through soil sampling directed by geospatial measurements of apparent s...

Electromagnetic Induction: A Computer-Assisted Experiment

ERIC Educational Resources Information Center

Fredrickson, J. E.; Moreland, L.

1972-01-01

By using minimal equipment it is possible to demonstrate Faraday's Law. An electronic desk calculator enables sophomore students to solve a difficult mathematical expression for the induced EMF. Polaroid pictures of the plot of induced EMF, together with the computer facility, enables students to make comparisons. (PS)

Geophysical investigation of the June 6, 1944 D-Day invasion site at Pointe du Hoc, Normandy, France

NASA Astrophysics Data System (ADS)

Everett, M. E.; Pierce, C. J.; Warden, R. R.; Burt, R. A.

2005-05-01

A near-surface geophysical survey at the D-Day invasion site atop the cliffs at Pointe du Hoc, Normandy, France was carried out using ground-penetrating radar, electromagnetic induction, and magnetic gradiometry equipment. The subsurface targets of investigation are predominantly buried concrete and steel structures and earthworks associated with the German coastal fortifications at this stronpoint of Hitler's Atlantic Wall. The targets are readily detectable embedded within the vadose zone of a weakly magnetic, electrically resistive loess soil cover. The radar and electromagnetic induction responses lend themselves to plan-view imaging of the subsurface, while the magnetics data reveal the presence of buried magnetic bodies in a more subtle fashion. Several intriguing geophysical signatures were discovered, including what may be the buried remains of a railway turntable, ordnance fragments in the bomb craters, a buried steel-reinforced concrete trench, and a linear chain of machine gun firing positins. Geophysical prospecting is shown to be a very powerful tool for historical battlefield characterization.

Ballistocardiogram of avian eggs determined by an electromagnetic induction coil.

PubMed

Ono, H; Akiyama, R; Sakamoto, Y; Pearson, J T; Tazawa, H

1997-07-01

As an avian embryo grows within an eggshell, the whole egg is moved by embryonic activity and also by the embryonic heartbeat. A technical interest in detecting minute biological movements has prompted the development of techniques and systems to measure the cardiogenic ballistic movement of the egg or ballistocardiogram (BCG). In this context, there is interest in using an electromagnetic induction coil (solenoid) as another simple sensor to measure the BCG and examining its possibility for BCG measurement. A small permanent magnet is attached tightly to the surface of an incubated egg, and then the egg with the magnet is placed in a solenoid. Preliminary model analysis is made to design a setup of the egg, magnet and solenoid coupling system. Then, simultaneous measurement with a laser displacement measuring system, developed previously, is made for chicken eggs, indicating that the solenoid detects the minute cardiogenic ballistic movements and that the BCG determined is a measure of the velocity of egg movements.

Induction machine bearing faults detection based on a multi-dimensional MUSIC algorithm and maximum likelihood estimation.

PubMed

Elbouchikhi, Elhoussin; Choqueuse, Vincent; Benbouzid, Mohamed

2016-07-01

Condition monitoring of electric drives is of paramount importance since it contributes to enhance the system reliability and availability. Moreover, the knowledge about the fault mode behavior is extremely important in order to improve system protection and fault-tolerant control. Fault detection and diagnosis in squirrel cage induction machines based on motor current signature analysis (MCSA) has been widely investigated. Several high resolution spectral estimation techniques have been developed and used to detect induction machine abnormal operating conditions. This paper focuses on the application of MCSA for the detection of abnormal mechanical conditions that may lead to induction machines failure. In fact, this paper is devoted to the detection of single-point defects in bearings based on parametric spectral estimation. A multi-dimensional MUSIC (MD MUSIC) algorithm has been developed for bearing faults detection based on bearing faults characteristic frequencies. This method has been used to estimate the fundamental frequency and the fault related frequency. Then, an amplitude estimator of the fault characteristic frequencies has been proposed and fault indicator has been derived for fault severity measurement. The proposed bearing faults detection approach is assessed using simulated stator currents data, issued from a coupled electromagnetic circuits approach for air-gap eccentricity emulating bearing faults. Then, experimental data are used for validation purposes. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Noninvasive inductive stent heating: alternative approach to prevent instent restenosis?

PubMed

Floren, Michael G; Günther, Rolf W; Schmitz-Rode, Thomas

2004-05-01

To test noninvasive inductive heating of implanted vascular stents as an alternative approach for reduction or prevention of neointimal hyperplasia. Calorimetric pretests were performed to get an orientation on the different parameters of influence for inductive heating of stents. The field strength was set to a maximum of 90 kA/m within a frequency range from 80 kHz to 320 kHz. The electromagnetic field was emitted by a custom-made water-cooled copper winding antenna. A flow model for stent heating was set up to assess the increase in temperature of an expanded 316L stainless steel stent with typical coronary stent dimensions of 3.5 mm diameter and 14.5 mm in length, and in a second setup with 4.5 mm diameter and 13 mm in length, respectively. The stent was located in a bioartificial artery, simulated by a fibrinogen matrix with a defined number of vital cells. The system was exposed to a pulsating perfusion and to an electromagnetic field of 200 kHz over a period of 20 minutes and in a second setup to an electromagnetic field of 300 kHz and increasing intensity up to maximum power-output. Afterward, the artificial vessel was sliced and examined by fluorescence microscopy to evaluate the number and location of damaged cells. The calorimetric tests show an exponential correlation of energy uptake in the stent with an increase in frequency and a constant generator output. At a frequency of 80 kHz, the power uptake accounts for 0.1 W (250 kHz 1.0 W; 320 kHz 1.9 W, respectively). The flow tests confirmed feasibility to elevate the stent temperature from 37 degrees C body temperature to 44 degrees C at 200 kHz within 55 seconds. The temperature increase of the fluid passing the heated vessel region was only marginal (maximum of 0.5 degrees C). Cell necrosis after 20 minutes of treatment was not observed. In a second set-up with 4.5 mm stent diameter, a frequency of 300 kHz and with maximum power output, the stent temperature was increased to 80 degrees C and there was extensive necrosis area around the stent. Treatment time and stent temperature were optimized in further tests. Selective noninvasive energy transfer to coronary stainless steel stents by inductive heating is possible within a wide range of power. By thermal conduction, vital cells close to the stent struts can be affected. The frequency of 200 kHz turned out to be favorable. There is still room for further optimization of energy dosage with regard to material and stent design, to induce controlled cell death. The method has potential to serve as an alternative approach for prevention of instent restenosis.

Single step vacuum-free and hydrogen-free synthesis of graphene

NASA Astrophysics Data System (ADS)

Orellana, Christian; Cunha, Thiago; Fantini, Cristiano; Jaques, Alonso; Häberle, Patricio

2017-08-01

We report a modified method to grow graphene in a single-step process. It is based on chemical vapor deposition and considers the use of methane under extremely adverse synthesis conditions, namely in an open chamber without requiring the addition of gaseous hydrogen in any of the synthesis stages. The synthesis occurs between two parallel Cu plates, heated up via electromagnetic induction. The inductive heating yields a strong thermal gradient between the catalytic substrates and the surrounding environment, promoting the enrichment of hydrogen generated as fragments of the methane molecules within the volume confined by the Cu foils. This induced density gradient is due to thermo-diffusion, also known as the Soret effect. Hydrogen and other low mass molecular fractions produced during the process inhibit oxidative effects and simultaneously reduce the native oxide on the Cu surface. As a result, high quality graphene is obtained on the inner surfaces of the Cu sheets as confirmed by Raman spectroscopy.

Design and analysis of a new flux-intensifying permanent magnet brushless motor with multilayer flux barriers

NASA Astrophysics Data System (ADS)

Yang, Shen; Zhu, Xiaoyong; Xiang, Zixuan; Fan, Deyang; Wu, Wenye; Yin, Jianing

2017-05-01

This paper proposes a new flux-intensifying permanent magnet brushless motor for potential application in electric vehicles. The key of the proposed motor is to adopt the concept of flux-intensifying effect, thus the preferable flux-weakening ability and extended speed range can be achieved. The usage of segmented and relatively thinner permanent magnet (PM) in the proposed motor contributes to the increase of d-axis inductance Ld. In addition, the multilayer flux barriers along q-axis flux path will effectively decrease q-axis inductance Lq. As a result, the unique feature of Ld>Lq can be obtained, which is beneficial to extending the speed range of the proposed motor. Furthermore, the flux-intensifying effect can reduce the risk of irreversible demagnetization in PMs. The electromagnetic performances of the proposed motor are analyzed and investigated in details by using the finite element methods, which demonstrate the excellent flux-weakening capability and wide speed range can be achieved in the proposed FI-PMBL motor.

Modular Approaches to Earth Science Scientific Computing: 3D Electromagnetic Induction Modeling as an Example

NASA Astrophysics Data System (ADS)

Tandon, K.; Egbert, G.; Siripunvaraporn, W.

2003-12-01

We are developing a modular system for three-dimensional inversion of electromagnetic (EM) induction data, using an object oriented programming approach. This approach allows us to modify the individual components of the inversion scheme proposed, and also reuse the components for variety of problems in earth science computing howsoever diverse they might be. In particular, the modularity allows us to (a) change modeling codes independently of inversion algorithm details; (b) experiment with new inversion algorithms; and (c) modify the way prior information is imposed in the inversion to test competing hypothesis and techniques required to solve an earth science problem. Our initial code development is for EM induction equations on a staggered grid, using iterative solution techniques in 3D. An example illustrated here is an experiment with the sensitivity of 3D magnetotelluric inversion to uncertainties in the boundary conditions required for regional induction problems. These boundary conditions should reflect the large-scale geoelectric structure of the study area, which is usually poorly constrained. In general for inversion of MT data, one fixes boundary conditions at the edge of the model domain, and adjusts the earth?s conductivity structure within the modeling domain. Allowing for errors in specification of the open boundary values is simple in principle, but no existing inversion codes that we are aware of have this feature. Adding a feature such as this is straightforward within the context of the modular approach. More generally, a modular approach provides an efficient methodology for setting up earth science computing problems to test various ideas. As a concrete illustration relevant to EM induction problems, we investigate the sensitivity of MT data near San Andreas Fault at Parkfield (California) to uncertainties in the regional geoelectric structure.

Increased nitric oxide synthase activity is essential for electromagnetic-pulse-induced blood-retinal barrier breakdown in vivo.

PubMed

Lu, Lianjun; Xu, Hui; Wang, Xiaowu; Guo, Guozhen

2009-04-06

To examine whether electromagnetic pulses (EMPs) affected the permeability of the blood-retinal barrier (BRB), gene expression of occludin and activity of nitric oxide synthase (NOS). Sprague-Dawley (SD) rats were used and randomized into EMP and control groups. Retinas were removed immediately, and 2 h or 24 h after EMP radiation. BRB permeability was analyzed by transmission electron microscopy and Evans Blue staining. Retinal NOS activity and concentrations of nitrite and nitrate were measured. Occludin mRNA and protein levels were detected by RT-PCR and Western blotting. Exposure of SD rats to EMP resulted in increased BRB permeability, with the greatest decrease in occludin at 24 h. Moreover, this permeability defect was also correlated with significant increases in the formation of NO and induction of NOS activity in SD rats. Furthermore, we found that treatment with NOS inhibitor N-nitro-L-arginine methyl ester (L-NAME) blocked BRB breakdown and prevented the increase in NO formation and induction of NOS activity, as well as the decrease in occluding expression. Taken together, these results support the view that NOS-dependent NO production is an important factor that contributes to EMP-induced BRB dysfunction, and suggests that NOS induction may play an important role in BRB breakdown.

The Circuit Theory Behind Coupled-Mode Magnetic Resonance-Based Wireless Power Transmission.

PubMed

Kiani, Mehdi; Ghovanloo, Maysam

2012-09-01

Inductive coupling is a viable scheme to wirelessly energize devices with a wide range of power requirements from nanowatts in radio frequency identification tags to milliwatts in implantable microelectronic devices, watts in mobile electronics, and kilowatts in electric cars. Several analytical methods for estimating the power transfer efficiency (PTE) across inductive power transmission links have been devised based on circuit and electromagnetic theories by electrical engineers and physicists, respectively. However, a direct side-by-side comparison between these two approaches is lacking. Here, we have analyzed the PTE of a pair of capacitively loaded inductors via reflected load theory (RLT) and compared it with a method known as coupled-mode theory (CMT). We have also derived PTE equations for multiple capacitively loaded inductors based on both RLT and CMT. We have proven that both methods basically result in the same set of equations in steady state and either method can be applied for short- or midrange coupling conditions. We have verified the accuracy of both methods through measurements, and also analyzed the transient response of a pair of capacitively loaded inductors. Our analysis shows that the CMT is only applicable to coils with high quality factor ( Q ) and large coupling distance. It simplifies the analysis by reducing the order of the differential equations by half compared to the circuit theory.

The Circuit Theory Behind Coupled-Mode Magnetic Resonance-Based Wireless Power Transmission

PubMed Central

Kiani, Mehdi; Ghovanloo, Maysam

2014-01-01

Inductive coupling is a viable scheme to wirelessly energize devices with a wide range of power requirements from nanowatts in radio frequency identification tags to milliwatts in implantable microelectronic devices, watts in mobile electronics, and kilowatts in electric cars. Several analytical methods for estimating the power transfer efficiency (PTE) across inductive power transmission links have been devised based on circuit and electromagnetic theories by electrical engineers and physicists, respectively. However, a direct side-by-side comparison between these two approaches is lacking. Here, we have analyzed the PTE of a pair of capacitively loaded inductors via reflected load theory (RLT) and compared it with a method known as coupled-mode theory (CMT). We have also derived PTE equations for multiple capacitively loaded inductors based on both RLT and CMT. We have proven that both methods basically result in the same set of equations in steady state and either method can be applied for short- or midrange coupling conditions. We have verified the accuracy of both methods through measurements, and also analyzed the transient response of a pair of capacitively loaded inductors. Our analysis shows that the CMT is only applicable to coils with high quality factor (Q) and large coupling distance. It simplifies the analysis by reducing the order of the differential equations by half compared to the circuit theory. PMID:24683368

L-C Measurement Acquisition Method for Aerospace Systems

NASA Technical Reports Server (NTRS)

Woodard, Stanley E.; Taylor, B. Douglas; Shams, Qamar A.; Fox, Robert L.

2003-01-01

This paper describes a measurement acquisition method for aerospace systems that eliminates the need for sensors to have physical connection to a power source (i.e., no lead wires) or to data acquisition equipment. Furthermore, the method does not require the sensors to be in proximity to any form of acquisition hardware. Multiple sensors can be interrogated using this method. The sensors consist of a capacitor, C(p), whose capacitance changes with changes to a physical property, p, electrically connected to an inductor, L. The method uses an antenna to broadcast electromagnetic energy that electrically excites one or more inductive-capacitive sensors via Faraday induction. This method facilitates measurements that were not previously possible because there was no practical means of providing power and data acquisition electrical connections to a sensor. Unlike traditional sensors, which measure only a single physical property, the manner in which the sensing element is interrogated simultaneously allows measurement of at least two unrelated physical properties (e.g., displacement rate and fluid level) by using each constituent of the L-C element. The key to using the method for aerospace applications is to increase the distance between the L-C elements and interrogating antenna; develop all key components to be non-obtrusive and to develop sensing elements that can easily be implemented. Techniques that have resulted in increased distance between antenna and sensor will be presented. Fluid-level measurements and pressure measurements using the acquisition method are demonstrated in the paper.

Coupled oscillators: interesting experiments for high school students

NASA Astrophysics Data System (ADS)

Kodejška, Č.; Lepil, O.; Sedláčková, H.

2018-07-01

This work deals with the experimental demonstration of coupled oscillators using simple tools in the form of mechanical coupled pendulums, magnetically coupled elastic strings or electromagnetic oscillators. For the evaluation of results the data logger Lab Quest Vernier and video analysis in the Tracker program were used. In the first part of this work, coupled mechanical oscillators of different types are shown and the data analysis by the Tracker or Vernier Logger Pro programs. The second part describes a measurement using two LC circuits with inductively or capacitive coupled electromagnetic oscillators and the obtained experimental results.

Numerical simulation of the alloying process during impulse induction heating of the metal substrate

NASA Astrophysics Data System (ADS)

Popov, V. N.

2017-10-01

2D numerical modeling of the processes during the alloying of the substrate surface metal layer is carried out. Heating, phase transition, heat and mass transfer in the molten metal, solidification of the melt are considered with the aid the proposed mathematical model. Under study is the applicability of the high-frequency electromagnetic field impulse for metal heating and melting. The distribution of the electromagnetic energy in the metal is described by empirical formulas. According to the results of numerical experiments, the flow structure in the melt and distribution of the alloying substances is evaluated.

Design and operation of a fast electromagnetic inductive massive gas injection valve for NSTX-U.

PubMed

Raman, R; Jarboe, T R; Nelson, B A; Gerhardt, S P; Lay, W-S; Plunkett, G J

2014-11-01

Results from the operation of an electromagnetic valve, that does not incorporate ferromagnetic materials, are presented. Image currents induced on a conducting disc placed near a pancake solenoid cause it to move away from the solenoid and open the vacuum seal. A new and important design feature is the use of Lip Seals for the sliding piston. The pressure rise in the test chamber is measured directly using a fast time response Baratron gauge. The valve injects over 200 Torr l of nitrogen in less than 3 ms, which remains unchanged at moderate magnetic fields.

Design and operation of a fast electromagnetic inductive massive gas injection valve for NSTX-U

NASA Astrophysics Data System (ADS)

Raman, R.; Jarboe, T. R.; Nelson, B. A.; Gerhardt, S. P.; Lay, W.-S.; Plunkett, G. J.

2014-11-01

Results from the operation of an electromagnetic valve, that does not incorporate ferromagnetic materials, are presented. Image currents induced on a conducting disc placed near a pancake solenoid cause it to move away from the solenoid and open the vacuum seal. A new and important design feature is the use of Lip Seals for the sliding piston. The pressure rise in the test chamber is measured directly using a fast time response Baratron gauge. The valve injects over 200 Torr l of nitrogen in less than 3 ms, which remains unchanged at moderate magnetic fields.

High-frequency magnetodielectric response in yttrium iron garnet at room temperature

NASA Astrophysics Data System (ADS)

Zhu, Jie; Liu, Yuan; Jia, Longfei; Zhang, Baoshan; Yang, Yi; Tang, Dongming

2018-05-01

Magnetic and dielectric properties of Yttrium Iron Garnet are measured over a frequency ranging from 0.5 GHz to 10 GHz with a magnetic field applied parallel to the propagation direction of the microwave. At the same time, the magnetodielectric phenomena are detected quantitatively. The maximum amplitude of the magnetodielectric coefficient is acquired at the ferromagnetic resonance frequency, and the value is up to 1.2% with the magnetic field of 1500 Oe applied. The phenomena have been explained by the Faraday's electromagnetic induction of the precession of the magnetic moments in the electromagnetic field at the ferromagnetic resonance frequency.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang Yu; Liu Jinliang; Fan Xuliang

In this paper, the electromagnetic dispersion theory and the classic telegraph equations were combined to calculate the important parameters of the helical Blumlein pulse forming line (BPFL) of accelerator based on tape helix. In the work band of the BPFL at several hundred ns range, electromagnetic dispersion characteristics were almost determined by the zeroth harmonic. In order to testify the dispersion theory of BPFL in this paper, filling dielectrics, such as de-ionized water, transformer oil, and air were employed in the helical BPFL, respectively. Parameters such as capacitance, inductance, characteristic impedance, and pulse duration of the BPFL were calculated. Effectsmore » of dispersion on these parameters were analyzed. Circuit simulation and electromagnetic simulation were carried out to prove these parameters of BPFL filled with these three kinds of dielectrics, respectively. The accelerator system was set up, and experimental results also corresponded to the theoretical calculations. The average theoretical errors of impedances and pulse durations were 3.5% and 3.4%, respectively, which proved the electromagnetic dispersion analyses in this paper.« less

Magma oceans and enhanced volcanism on TRAPPIST-1 planets due to induction heating

NASA Astrophysics Data System (ADS)

Kislyakova, K. G.; Noack, L.; Johnstone, C. P.; Zaitsev, V. V.; Fossati, L.; Lammer, H.; Khodachenko, M. L.; Odert, P.; Guedel, M.

2017-10-01

Low-mass M stars are plentiful in the Universe and often host small, rocky planets detectable with the current instrumentation. Recently, seven small planets have been discovered orbiting the ultracool dwarf TRAPPIST-1 te{Gillon16,Gillon17}. We examine the role of electromagnetic induction heating of these planets, caused by the star's rotation and the planet's orbital motion. If the stellar rotation and magnetic dipole axes are inclined with respect to each other, induction heating can melt the upper mantle and enormously increase volcanic activity, sometimes producing a magma ocean below the planetary surface. We show that induction heating leads the three innermost planets, one of which is in the habitable zone, to either evolve towards a molten mantle planet, or to experience increased outgassing and volcanic activity, while the four outermost planets remain mostly unaffected.

Every Day a New 3D Printing Material

ERIC Educational Resources Information Center

Hughes, Bill; Mona, Lynn; Wilson, Greg; Seamans, Jeff; McAninch, Steve; Stout, Heath

2017-01-01

A handful of technological episodes: fire, wheel and axle, Industrial Revolution, Faraday's discovery of electromagnetic induction, the transistor, and the digital age, have historically altered humanity. We are now witnessing/participating in the next transformational technology: 3D printing. Although dating back nearly 30 years, the technology…

A simplified regional-scale electromagnetic induction - Salinity calibration model using ANOCOVA modeling techniques

USDA-ARS?s Scientific Manuscript database

Directed soil sampling based on geospatial measurements of apparent soil electrical conductivity (ECa) is a potential means of characterizing the spatial variability of any soil property that influences ECa including soil salinity, water content, texture, bulk density, organic matter, and cation exc...

Ultra-Wideband EMI Sensing: Non-Metallic Target Detection and Automatic Classification of Unexploded Ordnance

NASA Astrophysics Data System (ADS)

Sigman, John Brevard

Buried explosive hazards present a pressing problem worldwide. Millions of acres and thousands of sites are contaminated in the United States alone [1, 2]. There are three categories of explosive hazards: metallic, intermediate-electrical conducting (IEC), and non-conducting targets. Metallic target detection and classification by electromagnetic (EM) signature has been the subject of research for many years. Key to the success of this research is modern multi-static Electromagnetic Induction (EMI) sensors, which are able to measure the wideband EMI response from metallic buried targets. However, no hardware solutions exist which can characterize IEC and non-conducting targets. While high-conducting metallic targets exhibit a quadrature peak response for frequencies in a traditional EMI regime under 100 kHz, the response of intermediate-conducting objects manifests at higher frequencies, between 100 kHz and 15 MHz. In addition to high-quality electromagnetic sensor data and robust electromagnetic models, a classification procedure is required to discriminate Targets of Interest (TOI) from clutter. Currently, costly human experts are used for this task. This expense and effort can be spared by using statistical signal processing and machine learning. This thesis has two main parts. In the first part, we explore using the high frequency EMI (HFEMI) band (100 kHz-15 MHz) for detection of carbon fiber UXO, voids, and of materials with characteristics that may be associated with improvised explosive devices (IED). We constructed an HFEMI sensing instrument, and apply the techniques of metal detection to sensing in a band of frequencies which are the transition between the induction and radar bands. In this transition domain, physical considerations and technological issues arise that cannot be solved via the approaches used in either of the bracketing lower and higher frequency ranges. In the second half of this thesis, we present a procedure for automatic classification of UXO. For maximum generality, our algorithm is robust and can handle sparse training examples of multi-class data. This procedure uses an unsupervised starter, semi-supervised techniques to gather training data, and concludes with supervised learning until all TOI are found. Additionally, an inference method for estimating the number of remaining true positives from a partial Receiver Operating Characteristic (ROC) curve is presented and applied to live-site dig histories.

Collection, processing, and quality assurance of time-series electromagnetic-induction log datasets, 1995–2016, south Florida

USGS Publications Warehouse

Prinos, Scott T.; Valderrama, Robert

2016-12-13

Time-series electromagnetic-induction log (TSEMIL) datasets are collected from polyvinyl-chloride cased or uncased monitoring wells to evaluate changes in water conductivity over time. TSEMIL datasets consist of a series of individual electromagnetic-induction logs, generally collected at a frequency of once per month or once per year that have been compiled into a dataset by eliminating small uniform offsets in bulk conductivity between logs probably caused by minor variations in calibration. These offsets are removed by selecting a depth at which no changes are apparent from year to year, and by adjusting individual logs to the median of all logs at the selected depth. Generally, the selected depths are within the freshwater saturated part of the aquifer, well below the water table. TSEMIL datasets can be used to monitor changes in water conductivity throughout the full thickness of an aquifer, without the need for long open-interval wells which have, in some instances, allowed vertical water flow within the well bore that has biased water conductivity profiles. The TSEMIL dataset compilation process enhances the ability to identify small differences between logs that were otherwise obscured by the offsets. As a result of TSEMIL dataset compilation, the root mean squared error of the linear regression between bulk conductivity of the electromagnetic-induction log measurements and the chloride concentration of water samples decreased from 17.4 to 1.7 millisiemens per meter in well G–3611 and from 3.7 to 2.2 millisiemens per meter in well G–3609. The primary use of the TSEMIL datasets in south Florida is to detect temporal changes in bulk conductivity associated with saltwater intrusion in the aquifer; however, other commonly observed changes include (1) variations in bulk conductivity near the water table where water saturation of pore spaces might vary and water temperature might be more variable, and (2) dissipation of conductive water in high-porosity rock layers, which might have entered these layers during drilling. Although TSEMIL dataset processing of even a few logs improves evaluations of the differences between the logs that are related to changes in the salinity, about 16 logs are needed to estimate the bulk conductivity within ±2 millisiemens per meter. Unlike many other types of data published by the U.S. Geological Survey, the median of TSEMIL datasets should not be considered final until 16 logs are collected and the median of the dataset is stable.

Modelling high frequency phenomena in the rotor of induction motors under no-load test conditions

NASA Astrophysics Data System (ADS)

Boglietti, Aldo; Bottauscio, Oriano; Chiampi, Mario; Lazzari, Mario

2003-01-01

The paper aims to deep the electromagnetic phenomena in the rotor of induction motors produced during the no-load test by the high-order harmonics of the spatial distribution of magnetic flux. The analysis is carried out by a flux driven finite element procedure, which can take into account the hysteresis of magnetic material, the induced currents in rotor cage and the eddy currents in the laminations. The computed results, including losses and local waveforms of electrical and magnetic quantities, are finally discussed.

High Frequency Electromagnetic Impedance Measurements for Characterization, Monitoring and Verification Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ki Ha; Becker, Alex; Framgos, William

1999-06-01

Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic measurements at frequencies between 1 and 100 MHz are important for such applications, because the induction number of many targets is small and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high-resolution imaging, accurate measurements are necessary so the field data can bemore » mapped into the space of the subsurface parameters. We are developing a non-invasive method for accurately imaging the electrical conductivity and dielectric permittivity of the shallow subsurface using the plane wave impedance approach. Electric and magnetic sensors are being tested in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques.« less

High-Frequency Electromagnetic Impedance Measurements for Characterization, Monitoring and Verification Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ki Ha; Becker, Alex; Tseng, Hung-Wen

2002-11-20

Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic (EM) measurements at frequencies between 1 and 100 MHz are important for such applications, because the induction number of many targets is small and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high-resolution imaging, accurate measurements are necessary so the field data canmore » be mapped into the space of the subsurface parameters. We are developing a non-invasive method for accurately mapping the electrical conductivity and dielectric permittivity of the shallow subsurface using the EM impedance approach (Frangos, 2001; Lee and Becker, 2001; Song et al., 2002). Electric and magnetic sensors are being tested in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques.« less

High-Frequency Electromagnetic Impedance Measurements for Characterization, Monitoring, and Verification Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ki Ha; Becker, Alex

2000-06-01

Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic measurements at frequencies between 1 and 100 MHz are important for such applications, because the induction number of many targets is small and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high-resolution imaging, accurate measurements are necessary so the field data can bemore » mapped into the space of the subsurface parameters. We are developing a non-invasive method for accurately imaging the electrical conductivity and dielectric permittivity of the shallow subsurface using the plane wave impedance approach (Song et al., 1997). Electric and magnetic sensors are being tested in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques.« less

High-Frequency Electromagnetic Impedance Measurements for Characterization, Monitoring and Verification Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ki Ha; Becker, Alex; Tseng, Hung-Wen

2001-06-10

Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic (EM) measurements at frequencies between 1 and 100 MHz are important for such applications, because the induction number of many targets is small and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high-resolution imaging, accurate measurements are necessary so the field data canmore » be mapped into the space of the subsurface parameters. We are developing a non-invasive method for accurately mapping the electrical conductivity and dielectric permittivity of the shallow subsurface using the EM impedance approach (Frangos, 2001; Lee and Becker, 2001). Electric and magnetic sensors are being tested in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques.« less

The birth of the electric machines: a commentary on Faraday (1832) 'Experimental researches in electricity'.

PubMed

Al-Khalili, Jim

2015-04-13

The history of science is filled with examples of key discoveries and breakthroughs that have been published as landmark texts or journal papers, and to which one can trace the origins of whole disciplines. Such paradigm-shifting publications include Copernicus' De revolutionibus orbium coelestium (1543), Isaac Newton's Philosophiæ Naturalis Principia Mathematica (1687) and Albert Einstein's papers on relativity (1905 and 1915). Michael Faraday's 1832 paper on electromagnetic induction sits proudly among these works and in a sense can be regarded as having an almost immediate effect in transforming our world in a very real sense more than any of the others listed. Here we review the status of the subject-the relationship between magnetism and electricity both before and after Faraday's paper and delve into the details of the key experiments he carried out at the Royal Institution outlining clearly how he discovered the process of electromagnetic induction, whereby an electric current could be induced to flow through a conductor that experiences a changing magnetic field. His ideas would not only enable Maxwell's later development of his theory of classical electromagnetism, but would directly lead to the development of the electric dynamo and electric motor, two technological advances that are the very foundations of the modern world. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society.

Electromagnetic Basis of Metabolism and Heredity

NASA Technical Reports Server (NTRS)

Freund, Friedemann; Stolc, Viktor

2016-01-01

Living organisms control their cellular biological clocks to maintain functional oscillation of the redox cycle, also called the "metabolic cycle" or "respiratory cycle". Organization of cellular processes requires parallel processing on a synchronized time-base. These clocks coordinate the timing of all biochemical processes in the cell, including energy production, DNA replication, and RNA transcription. When this universal time keeping function is perturbed by exogenous induction of reactive oxygen species (ROS), the rate of metabolism changes. This causes oxidative stress, aging and mutations. Therefore, good temporal coordination of the redox cycle not only actively prevents chemical conflict between the reductive and oxidative partial reactions; it also maintains genome integrity and lifespan. Moreover, this universal biochemical rhythm can be disrupted by ROS induction in vivo. This in turn can be achieved by blocking the electron transport chain either endogenously or exogenously by various metabolites, e.g. hydrogen sulfide (H2S), highly diffusible drugs, and carbon monoxide (CO). Alternatively, the electron transport in vivo can be attenuated via a coherent or interfering transfer of energy from exogenous ultralow frequency (ULF) and extremely low frequency (ELF) electromagnetic (EM) fields, suggesting that-on Earth-such ambient fields are an omnipresent (and probably crucially important) factor for the time-setting basis of universal biochemical reactions in living cells. Our work demonstrated previously un-described evidence for quantum effects in biology by electromagnetic coupling below thermal noise at the universal electron transport chain (ETC) in vivo.

The birth of the electric machines: a commentary on Faraday (1832) ‘Experimental researches in electricity’

PubMed Central

Al-Khalili, Jim

2015-01-01

The history of science is filled with examples of key discoveries and breakthroughs that have been published as landmark texts or journal papers, and to which one can trace the origins of whole disciplines. Such paradigm-shifting publications include Copernicus' De revolutionibus orbium coelestium (1543), Isaac Newton's Philosophiæ Naturalis Principia Mathematica (1687) and Albert Einstein's papers on relativity (1905 and 1915). Michael Faraday's 1832 paper on electromagnetic induction sits proudly among these works and in a sense can be regarded as having an almost immediate effect in transforming our world in a very real sense more than any of the others listed. Here we review the status of the subject—the relationship between magnetism and electricity both before and after Faraday's paper and delve into the details of the key experiments he carried out at the Royal Institution outlining clearly how he discovered the process of electromagnetic induction, whereby an electric current could be induced to flow through a conductor that experiences a changing magnetic field. His ideas would not only enable Maxwell's later development of his theory of classical electromagnetism, but would directly lead to the development of the electric dynamo and electric motor, two technological advances that are the very foundations of the modern world. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society. PMID:25750145

Exploring soils and ecohydrological structure in small watersheds using electromagnetic induction

USDA-ARS?s Scientific Manuscript database

Soil moisture sensors generally strive to use the real permittivity as the basis for estimating soil water content from measured electrical properties of soil. It has been shown that a reasonably good general calibration can be developed for mineral soils on this basis. However, at the low measureme...

Experimental Confirmation of Lenz's Law

ERIC Educational Resources Information Center

Mayer, V. V.; Varaksina, E. I.

2017-01-01

The paper presents a series of experiments that demonstrate the phenomenon of electromagnetic induction. These make it possible to determine the direction of the induced current and so confirm Lenz's Law. The simple experiments can be reproduced in a school laboratory and can be recommended for students' project activity.

Hall Effect in a Moving Liquid

ERIC Educational Resources Information Center

Di Lieto, Alberto; Giuliano, Alessia; Maccarrone, Francesco; Paffuti, Giampiero

2012-01-01

A simple experiment, suitable for performing in an undergraduate physics laboratory, illustrates electromagnetic induction through the water entering into a cylindrical rubber tube by detecting the voltage developed across the tube in the direction transverse both to the flow velocity and to the magnetic field. The apparatus is a very simple…

Using electromagnetic induction technology to predict volatile fatty acid, source area differences

USDA-ARS?s Scientific Manuscript database

Subsurface sampling techniques have been adapted to measure manure accumulation on feedlot surface. Objectives of this study were to determine if sensor data could be used to predict differences in volatile fatty acids (VFA) and other volatiles produced on the feedlot surface three days following a...

75 FR 22031 - Energy Conservation Program for Consumer Products and Certain Commercial and Industrial Equipment...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-27

..., including induction and fluorescent. Non-HID technologies are achieving market penetration in lighting... the electromagnetic (magnetic) type. The industry-accepted life of magnetic ballasts is 50,000 hours... analysis for today's proposed determination, DOE only considered magnetic ballasts because they are the...

Experimental confirmation of Lenz’s law

NASA Astrophysics Data System (ADS)

Mayer, V. V.; Varaksina, E. I.

2017-11-01

The paper presents a series of experiments that demonstrate the phenomenon of electromagnetic induction. These make it possible to determine the direction of the induced current and so confirm Lenz’s Law. The simple experiments can be reproduced in a school laboratory and can be recommended for students’ project activity.

Bipolar square-wave current source for transient electromagnetic systems based on constant shutdown time

NASA Astrophysics Data System (ADS)

Wang, Shilong; Yin, Changchun; Lin, Jun; Yang, Yu; Hu, Xueyan

2016-03-01

Cooperative work of multiple magnetic transmitting sources is a new trend in the development of transient electromagnetic system. The key is the bipolar current waves shutdown, concurrently in the inductive load. In the past, it was difficult to use the constant clamping voltage technique to realize the synchronized shutdown of currents with different peak values. Based on clamping voltage technique, we introduce a new controlling method with constant shutdown time. We use the rising time to control shutdown time and use low voltage power source to control peak current. From the viewpoint of the circuit energy loss, by taking the high-voltage capacitor bypass resistance and the capacitor of the passive snubber circuit into account, we establish the relationship between the rising time and the shutdown time. Since the switch is not ideal, we propose a new method to test the shutdown time by the low voltage, the high voltage and the peak current. Experimental results show that adjustment of the current rising time can precisely control the value of the clamp voltage. When the rising time is fixed, the shutdown time is unchanged. The error for shutdown time deduced from the energy consumption is less than 6%. The new controlling method on current shutdown proposed in this paper can be used in the cooperative work of borehole and ground transmitting system.

Bipolar square-wave current source for transient electromagnetic systems based on constant shutdown time.

PubMed

Wang, Shilong; Yin, Changchun; Lin, Jun; Yang, Yu; Hu, Xueyan

2016-03-01

Cooperative work of multiple magnetic transmitting sources is a new trend in the development of transient electromagnetic system. The key is the bipolar current waves shutdown, concurrently in the inductive load. In the past, it was difficult to use the constant clamping voltage technique to realize the synchronized shutdown of currents with different peak values. Based on clamping voltage technique, we introduce a new controlling method with constant shutdown time. We use the rising time to control shutdown time and use low voltage power source to control peak current. From the viewpoint of the circuit energy loss, by taking the high-voltage capacitor bypass resistance and the capacitor of the passive snubber circuit into account, we establish the relationship between the rising time and the shutdown time. Since the switch is not ideal, we propose a new method to test the shutdown time by the low voltage, the high voltage and the peak current. Experimental results show that adjustment of the current rising time can precisely control the value of the clamp voltage. When the rising time is fixed, the shutdown time is unchanged. The error for shutdown time deduced from the energy consumption is less than 6%. The new controlling method on current shutdown proposed in this paper can be used in the cooperative work of borehole and ground transmitting system.

[Changes in the chromatin structure of lymphoid cells under the influence of low-intensity extremely high-frequency electromagnetic radiation against the background of inflammatory process].

PubMed

Gapeev, A B; Romanova, N A; Chemeris, N K

2011-01-01

Using the alkaline single cell gel electrophoresis technique (comet assay), changes in chromatin structure of peripheral blood leukocytes and peritoneal neutrophils have been studied in mice exposed to low-intensity extremely high-frequency electromagnetic radiation (42.2 GHz, 0.1 mW/cm2, 20 min at 1 h after induction of inflammation) against the background of the systemic inflammatory process. It was revealed that the exposure of mice with the developing inflammation leads to a pronounced decrease in the level of DNA damage to peripheral blood leukocytes and peritoneal neutrophils. It is supposed that the changes in the chromatin structure of lymphoid cells have a genoprotective character in the inflammatory process and can underlie the mechanisms of realization of antiinflammatory effects of the electromagnetic radiation.

Mapping patterns of soil properties and soil moisture using electromagnetic induction to investigate the impact of land use changes on soil processes

NASA Astrophysics Data System (ADS)

Robinet, Jérémy; von Hebel, Christian; van der Kruk, Jan; Govers, Gerard; Vanderborght, Jan

2016-04-01

As highlighted by many authors, classical or geophysical techniques for measuring soil moisture such as destructive soil sampling, neutron probes or Time Domain Reflectometry (TDR) have some major drawbacks. Among other things, they provide point scale information, are often intrusive and time-consuming. ElectroMagnetic Induction (EMI) instruments are often cited as a promising alternative hydrogeophysical methods providing more efficiently soil moisture measurements ranging from hillslope to catchment scale. The overall objective of our research project is to investigate whether a combination of geophysical techniques at various scales can be used to study the impact of land use change on temporal and spatial variations of soil moisture and soil properties. In our work, apparent electrical conductivity (ECa) patterns are obtained with an EM multiconfiguration system. Depth profiles of ECa were subsequently inferred through a calibration-inversion procedure based on TDR data. The obtained spatial patterns of these profiles were linked to soil profile and soil water content distributions. Two catchments with contrasting land use (agriculture vs. natural forest) were selected in a subtropical region in the south of Brazil. On selected slopes within the catchments, combined EMI and TDR measurements were carried out simultaneously, under different atmospheric and soil moisture conditions. Ground-truth data for soil properties were obtained through soil sampling and auger profiles. The comparison of these data provided information about the potential of the EMI technique to deliver qualitative and quantitative information about the variability of soil moisture and soil properties.

Design Optimization of an Electromagnetic Energy Harvester Backpack for Utilization of Human Walking Energy

NASA Astrophysics Data System (ADS)

Mullen, Christopher

Implementation of energy harvesting technology can provide a sustainable, remote power source for soldiers by reducing the battery weight and allowing them to stay in the field for longer periods of time. Among multiple energy conversion principles, electromagnetic induction can scavenge energy from wasted kinematic and vibration energy found from human motion. Hip displacement during human gait acts as a base excitation for an energy harvesting backpack system. The placement of a permanent magnet in this vibration environment results in relative motion of the magnet to the coil of copper wire, which induces an electric current. This current can be saved to a battery or capacitor bank installed on the backpack to be used to power electronic devices. The purpose of this research is to construct a reliable simulation model for an electromagnetic vibration energy harvester and use it for a multi-variable optimization algorithm to identify an optimal coil and magnet layout for highest power output. Key components of the coupled equations of motion such as the magnetic flux density and coil inductance are obtained using ANSYS multi-physics software or by measuring them. These components are fed into a harvester simulation model (e.g. coupled field equations of motion for the backpack harvester) that generates the electrical power output. The developed simulation model is verified with multiple case studies including an experimental test. Then the optimal design parameters in the simulation model (e.g., magnet layout, coil width, outer coil diameter, external load resistance) are identified for maximum power. Results from this study will pave the way for a more efficient energy harvesting backpack while providing better insight into the efficiency of magnet and coil layout for electromagnetic applications.

Experimental verification and optimization of a linear electromagnetic energy harvesting device

NASA Astrophysics Data System (ADS)

Mullen, Christopher; Lee, Soobum

2017-04-01

Implementation of energy harvesting technology can provide a sustainable, remote power source for soldiers by reducing the battery weight and allowing them to stay in the field for longer periods of time. Among multiple energy conversion principles, electromagnetic induction can scavenge energy from wasted kinematic and vibration energy found from human motion. Hip displacement during human gait acts as a base excitation for an energy harvesting backpack system. The placement of a permanent magnet in this vibration environment results in relative motion of the magnet to the coil of copper wire, which induces an electric current. This current can be saved to a battery or capacitor bank installed on the backpack to be used to power electronic devices. The purpose of this research is to construct a reliable simulation model for an electromagnetic vibration energy harvester and use it for a multi-variable optimization algorithm to identify an optimal coil and magnet layout for highest power output. Key components of the coupled equations of motion such as the magnetic flux density and coil inductance are obtained using ANSYS multi-physics software or by measuring them. These components are fed into a harvester simulation model (e.g. coupled field equations of motion for the backpack harvester) that generates the electrical power output. The developed simulation model is verified with a case study including an experimental test. Then the optimal design parameters in the simulation model (e.g., magnet layout, coil width, outer coil diameter, external load resistance) are identified for maximum power. Results from this study will pave the way for a more efficient energy harvesting backpack while providing better insight into the efficiency of magnet and coil layout for electromagnetic applications.

The detection of brain ischaemia in rats by inductive phase shift spectroscopy.

PubMed

González, C A; Villanueva, C; Vera, C; Flores, O; Reyes, R D; Rubinsky, B

2009-08-01

Ischaemia in the brain is an important clinical problem that is often monitored and studied with expensive devices such as MRI and PET, which are not readily available in low economical resource parts of the world. We have developed a new less expensive tool for non-invasive monitoring of ischaemia in the brain. This is a first feasibility study describing the concept. The system is based on the hypothesis that electromagnetic properties of the tissue change during ischaemia and that measuring the electromagnetic properties of the bulk of the brain with non-contact means can detect these changes. The apparatus we have built and whose design we describe here consists of two electromagnetic coils placed around the head. The system measures the bulk change in time of the phase difference between the electromagnetic signal on the two coils in a range of frequencies. A mathematical model simulating the device and the measurement is also introduced. Ischaemia was induced in the brain of rats by occlusion of the right cerebral and carotid arteries. Experimental subjects were monitored for 24 h. Inductive phase shift measurements were made at five frequencies in the range of 0.1-50 MHz eight times during the observation period. An ex vivo estimation of the percentage of necrosis in the ischemic subjects at t = 24 h was done. The mathematical model was also applied to the experimental tested situation. The results of both experiments and theory show significant phase shifts increase as a function of frequency and ischaemia time. The theoretical and experimental results suggest that the tested technique has the potential to detect the processes and level of ischaemia in the brain by non-invasive, continuous, bulk volumetric monitoring with a simple and inexpensive apparatus.

The Scientific Papers of James Prescott Joule 2 Volume Set

NASA Astrophysics Data System (ADS)

Prescott Joule, James

2011-03-01

Volume 1: Description of an electro-magnetic engine; Description of an electro-magnetic engine, with experiments; On the use of electro-magnets made of iron wire for the electro-magnetic engine; Investigations in magnetism and electro-magnetism; Investigations in magnetism and electro-magnetism; Description of an electro-magnetic engine; On electro-magnetic forces; On electro-magnetic forces; On electro-magnetic forces; Description of a new electro-magnet; On a new class of magnetic forces; On voltaic apparatus; On the production of heat by voltaic electricity; On the heat evolved by metallic conductors of electricity, and in the cells of a battery during electrolysis; On the electric origin of the heat of combustion; On the electrical origin of chemical heat; On Sir G. C. Haughton's experiments; On the heat evolved during the electrolysis of water; On the calorific effects of magneto-electricity, and on the mechanical value of heat; On the intermittent character of the voltaic current in certain cases of electrolysis; and on the intensities of various voltaic arrangements; On the changes of temperature produced by the rarefaction and condensation of air; On specific heat; On a new method for ascertaining the specific heat of bodies; Note on the employment of electrical currents for ascertaining the specific heat of bodies; On the mechanical equivalent of heat; On the existence of an equivalent relation between heat and the ordinary forms of mechanical power; On the heat disengaged in chemical combinations; On the effects of magnetism upon the dimensions of iron and steel bars; On matter, living force, and heat; On the mechanical equivalent of heat, as determined from the heat evolved by the function of fluids; On the theoretical velocity of sound; Expériences sur l'identité entre le calorique et la force méchanique. Détermination de l'équivalent par la chaleur dégagée pendant la friction du mercure; On shooting-stars; On the mechanical equivalent of heat, and on the constitution of elastic fluids; Some remarks on heat and the constitution of elastic fluids; On the mechanical equivalent of heat; On a remarkable appearance of lightning; On some amalgams; On the air-engine; Account of experiments with a powerful electro-magnet; On the economical production of mechanical effect from chemical forces; An account of some experiments with a large electro-magnet; Introductory research on the induction of magnetism by electric currents; On the fusion of metals by voltaic electricity; Note on Dalton's determination of the expansion of air by heat; On the utilization of the sewage of London and other large towns; Notice of experiments on the heat developed by friction in air; On the intensity of light during the recent solar eclipse; On an improved galvanometer; On the thermo-electricity of ferruginous metals, and on the thermal effects of stretching solid bodies; On the thermal effects of longitudinal compression of solids, with an investigation on the alterations of temperature accompanying changes of pressure in fluids; On some thermo-dynamic properties of solids; On the thermal effects of compressing fluids; On a method of testing the strength of steam-boilers; Experiments on the total heat of steam; Experiments on the passage of air through pipes and apertures in thin plates; On some amalgams; On the probable cause of electric storms; On the surface-condensation of steam; Notice of a compressing air-pump; Note on a mirage at Douglas; On a sensitive barometer; On a sensitive thermometer; Note on the meteor of February 6th, 1818; On a method of hardening steel wires for magnetic needles; On an instrument for showing rapid changes in magnetic declination; Determination of the dynamical equivalent of heat from the thermal effects of electric currents; Observations on the alteration of the freezing-point in thermometers; On a new

Induction plasma tube

DOEpatents

Hull, D.E.

1982-07-02

An induction plasma tube having a segmented, fluid-cooled internal radiation shield is disclosed. The individual segments are thick in cross-section such that the shield occupies a substantial fraction of the internal volume of the plasma enclosure, resulting in improved performance and higher sustainable plasma temperatures. The individual segments of the shield are preferably cooled by means of a counterflow fluid cooling system wherein each segment includes a central bore and a fluid supply tube extending into the bore. The counterflow cooling system results in improved cooling of the individual segments and also permits use of relatively larger shield segments which permit improved electromagnetic coupling between the induction coil and a plasma located inside the shield. Four embodiments of the invention, each having particular advantages, are disclosed.

Induction plasma tube

DOEpatents

Hull, Donald E.

1984-01-01

An induction plasma tube having a segmented, fluid-cooled internal radiation shield is disclosed. The individual segments are thick in cross-section such that the shield occupies a substantial fraction of the internal volume of the plasma enclosure, resulting in improved performance and higher sustainable plasma temperatures. The individual segments of the shield are preferably cooled by means of a counterflow fluid cooling system wherein each segment includes a central bore and a fluid supply tube extending into the bore. The counterflow cooling system results in improved cooling of the individual segments and also permits use of relatively larger shield segments which permit improved electromagnetic coupling between the induction coil and a plasma located inside the shield. Four embodiments of the invention, each having particular advantages, are disclosed.

Experiments and Demonstrations in Physics: Bar-Ilan Physics Laboratory (2nd Edition)

NASA Astrophysics Data System (ADS)

Kraftmakher, Yaakov

2014-08-01

The following sections are included: * Data-acquisition systems from PASCO * ScienceWorkshop 750 Interface and DataStudio software * 850 Universal Interface and Capstone software * Mass on spring * Torsional pendulum * Hooke's law * Characteristics of DC source * Digital storage oscilloscope * Charging and discharging a capacitor * Charge and energy stored in a capacitor * Speed of sound in air * Lissajous patterns * I-V characteristics * Light bulb * Short time intervals * Temperature measurements * Oersted's great discovery * Magnetic field measurements * Magnetic force * Magnetic braking * Curie's point I * Electric power in AC circuits * Faraday's law of induction I * Self-inductance and mutual inductance * Electromagnetic screening * LCR circuit I * Coupled LCR circuits * Probability functions * Photometric laws * Kirchhoff's rule for thermal radiation * Malus' law * Infrared radiation * Irradiance and illuminance

A combined joint diagonalization-MUSIC algorithm for subsurface targets localization

NASA Astrophysics Data System (ADS)

Wang, Yinlin; Sigman, John B.; Barrowes, Benjamin E.; O'Neill, Kevin; Shubitidze, Fridon

2014-06-01

This paper presents a combined joint diagonalization (JD) and multiple signal classification (MUSIC) algorithm for estimating subsurface objects locations from electromagnetic induction (EMI) sensor data, without solving ill-posed inverse-scattering problems. JD is a numerical technique that finds the common eigenvectors that diagonalize a set of multistatic response (MSR) matrices measured by a time-domain EMI sensor. Eigenvalues from targets of interest (TOI) can be then distinguished automatically from noise-related eigenvalues. Filtering is also carried out in JD to improve the signal-to-noise ratio (SNR) of the data. The MUSIC algorithm utilizes the orthogonality between the signal and noise subspaces in the MSR matrix, which can be separated with information provided by JD. An array of theoreticallycalculated Green's functions are then projected onto the noise subspace, and the location of the target is estimated by the minimum of the projection owing to the orthogonality. This combined method is applied to data from the Time-Domain Electromagnetic Multisensor Towed Array Detection System (TEMTADS). Examples of TEMTADS test stand data and field data collected at Spencer Range, Tennessee are analyzed and presented. Results indicate that due to its noniterative mechanism, the method can be executed fast enough to provide real-time estimation of objects' locations in the field.

Realistic Subsurface Anomaly Discrimination Using Electromagnetic Induction and an SVM Classifier

NASA Astrophysics Data System (ADS)

Pablo Fernández, Juan; Shubitidze, Fridon; Shamatava, Irma; Barrowes, Benjamin E.; O'Neill, Kevin

2010-12-01

The environmental research program of the United States military has set up blind tests for detection and discrimination of unexploded ordnance. One such test consists of measurements taken with the EM-63 sensor at Camp Sibert, AL. We review the performance on the test of a procedure that combines a field-potential (HAP) method to locate targets, the normalized surface magnetic source (NSMS) model to characterize them, and a support vector machine (SVM) to classify them. The HAP method infers location from the scattered magnetic field and its associated scalar potential, the latter reconstructed using equivalent sources. NSMS replaces the target with an enclosing spheroid of equivalent radial magnetization whose integral it uses as a discriminator. SVM generalizes from empirical evidence and can be adapted for multiclass discrimination using a voting system. Our method identifies all potentially dangerous targets correctly and has a false-alarm rate of about 5%.

Three-dimensional sensitivity distribution and sample volume of low-induction-number electromagnetic-induction instruments

USGS Publications Warehouse

Callegary, J.B.; Ferré, T.P.A.; Groom, R.W.

2012-01-01

There is an ongoing effort to improve the understanding of the correlation of soil properties with apparent soil electrical conductivity as measured by low-induction-number electromagnetic-induction (LIN FEM) instruments. At a minimum, the dimensions of LIN FEM instruments' sample volume, the spatial distribution of sensitivity within that volume, and implications for surveying and analyses must be clearly defined and discussed. Therefore, a series of numerical simulations was done in which a conductive perturbation was moved systematically through homogeneous soil to elucidate the three-dimensional sample volume of LIN FEM instruments. For a small perturbation with electrical conductivity similar to that of the soil, instrument response is a measure of local sensitivity (LS). Our results indicate that LS depends strongly on the orientation of the instrument's transmitter and receiver coils and includes regions of both positive and negative LS. Integration of the absolute value of LS from highest to lowest was used to contour cumulative sensitivity (CS). The 90% CS contour was used to define the sample volume. For both horizontal and vertical coplanar coil orientations, the longest dimension of the sample volume was at the surface along the main instrument axis with a length of about four times the intercoil spacing (s) with maximum thicknesses of about 1 and 0.3 s, respectively. The imaged distribution of spatial sensitivity within the sample volume is highly complex and should be considered in conjunction with the expected scale of heterogeneity before the use and interpretation of LIN FEM for mapping and profiling. ?? Soil Science Society of America.

Split Octonion Reformulation for Electromagnetic Chiral Media of Massive Dyons

NASA Astrophysics Data System (ADS)

Chanyal, B. C.

2017-12-01

In an explicit, unified, and covariant formulation of an octonion algebra, we study and generalize the electromagnetic chiral fields equations of massive dyons with the split octonionic representation. Starting with 2×2 Zorn’s vector matrix realization of split-octonion and its dual Euclidean spaces, we represent the unified structure of split octonionic electric and magnetic induction vectors for chiral media. As such, in present paper, we describe the chiral parameter and pairing constants in terms of split octonionic matrix representation of Drude-Born-Fedorov constitutive relations. We have expressed a split octonionic electromagnetic field vector for chiral media, which exhibits the unified field structure of electric and magnetic chiral fields of dyons. The beauty of split octonionic representation of Zorn vector matrix realization is that, the every scalar and vector components have its own meaning in the generalized chiral electromagnetism of dyons. Correspondingly, we obtained the alternative form of generalized Proca-Maxwell’s equations of massive dyons in chiral media. Furthermore, the continuity equations, Poynting theorem and wave propagation for generalized electromagnetic fields of chiral media of massive dyons are established by split octonionic form of Zorn vector matrix algebra.

Electromagnetic pulses bone healing booster

NASA Astrophysics Data System (ADS)

Sintea, S. R.; Pomazan, V. M.; Bica, D.; Grebenisan, D.; Bordea, N.

2015-11-01

Posttraumatic bone restoration triggered by the need to assist and stimulate compensatory bone growth in periodontal condition. Recent studies state that specific electromagnetic stimulation can boost the bone restoration, reaching up to 30% decrease in recovery time. Based on the existing data on the electromagnetic parameters, a digital electronic device is proposed for intra oral mounting and bone restoration stimulation in periodontal condition. The electrical signal is applied to an inductive mark that will create and impregnate magnetic field in diseased tissue. The device also monitors the status of the electromagnetic field. Controlled wave forms and pulse frequency signal at programmable intervals are obtained with optimized number of components and miniaturized using surface mounting devices (SMD) circuits and surface mounting technology (SMT), with enhanced protection against abnormal current growth, given the intra-oral environment. The system is powered by an autonomous power supply (battery), to limit the problems caused by powering medical equipment from the main power supply. Currently the device is used in clinical testing, in cycles of six up to twelve months. Basic principles for the electrical scheme and algorithms for pulse generation, pulse control, electromagnetic field control and automation of current monitoring are presented, together with the friendly user interface, suitable for medical data and patient monitoring.

Plasma Generator Using Spiral Conductors

NASA Technical Reports Server (NTRS)

Szatkowski, George N. (Inventor); Dudley, Kenneth L. (Inventor); Ticatch, Larry A. (Inventor); Smith, Laura J. (Inventor); Koppen, Sandra V. (Inventor); Nguyen, Truong X. (Inventor); Ely, Jay J. (Inventor)

2016-01-01

A plasma generator includes a pair of identical spiraled electrical conductors separated by dielectric material. Both spiraled conductors have inductance and capacitance wherein, in the presence of a time-varying electromagnetic field, the spiraled conductors resonate to generate a harmonic electromagnetic field response. The spiraled conductors lie in parallel planes and partially overlap one another in a direction perpendicular to the parallel planes. The geometric centers of the spiraled conductors define endpoints of a line that is non-perpendicular with respect to the parallel planes. A voltage source coupled across the spiraled conductors applies a voltage sufficient to generate a plasma in at least a portion of the dielectric material.

Effect of 900 MHz Electromagnetic Radiation on the Induction of ROS in Human Peripheral Blood Mononuclear Cells.

PubMed

Kazemi, E; Mortazavi, S M J; Ali-Ghanbari, A; Sharifzadeh, S; Ranjbaran, R; Mostafavi-Pour, Z; Zal, F; Haghani, M

2015-09-01

Despite numerous studies over a decade, it still remains controversial about the biological effects of RF EMF emitted by mobile phone telephony. Here we investigated the effect of 900 MHz GSM on the induction of oxidative stress and the level of intracellular reactive oxygen species (ROS) in human mononuclear cells, monocytes and lymphocytes as defence system cells. 6 ml Peripheral Blood samples were obtained from 13 healthy volunteers (21-30 year-old). Each sample was devided into 2 groups: one was exposed RF radiation emitted from a mobile phone simulator for 2 hour and the other used as control group which was not exposed to any fields. After that, mononuclear cells were isolated from peripheral blood by density gradient centrifugation in Ficoll-Paque. The intracellular ROS content in monocytes and lymphocytes was measured by the CM-H2DCFDA fluorescence probe using flowcytometry technique. Our results showed significant increase in  ROS production after exposure in population rich in monocytes. This effect was not significant in population rich in lymphocytes in comparison with non exposed cells. The results obtained in this study clearly showed the oxidative stress induction capability of RF electromagnetic field in the portion of PBMCs mostly in monocytes, like the case of exposure to micro organisms, although the advantages or disadvantages of this effect should be evaluated.

Bats Avoid Radar Installations: Could Electromagnetic Fields Deter Bats from Colliding with Wind Turbines?

PubMed Central

Nicholls, Barry; Racey, Paul A.

2007-01-01

Large numbers of bats are killed by collisions with wind turbines, and there is at present no direct method of reducing or preventing this mortality. We therefore determine whether the electromagnetic radiation associated with radar installations can elicit an aversive behavioural response in foraging bats. Four civil air traffic control (ATC) radar stations, three military ATC radars and three weather radars were selected, each surrounded by heterogeneous habitat. Three sampling points matched for habitat type and structure, dominant vegetation species, altitude and surrounding land class were located at increasing distances from each station. A portable electromagnetic field meter measured the field strength of the radar at three distances from the source: in close proximity (<200 m) with a high electromagnetic field (EMF) strength >2 volts/metre, an intermediate point within line of sight of the radar (200–400 m) and with an EMF strength <2 v/m, and a control site out of sight of the radar (>400 m) and registering an EMF of zero v/m. At each radar station bat activity was recorded three times with three independent sampling points monitored on each occasion, resulting in a total of 90 samples, 30 of which were obtained within each field strength category. At these sampling points, bat activity was recorded using an automatic bat recording station, operated from sunset to sunrise. Bat activity was significantly reduced in habitats exposed to an EMF strength of greater than 2 v/m when compared to matched sites registering EMF levels of zero. The reduction in bat activity was not significantly different at lower levels of EMF strength within 400 m of the radar. We predict that the reduction in bat activity within habitats exposed to electromagnetic radiation may be a result of thermal induction and an increased risk of hyperthermia. PMID:17372629

Magnetoacoustic Tomography with Magnetic Induction for Electrical Conductivity based Tissue imaging

NASA Astrophysics Data System (ADS)

Mariappan, Leo

Electrical conductivity imaging of biological tissue has attracted considerable interest in recent years owing to research indicating that electrical properties, especially electrical conductivity and permittivity, are indicators of underlying physiological and pathological conditions in biological tissue. Also, the knowledge of electrical conductivity of biological tissue is of interest to researchers conducting electromagnetic source imaging and in design of devices that apply electromagnetic energy to the body such as MRI. So, the need for a non-invasive, high resolution impedance imaging method is highly desired. To address this need we have studied the magnetoacoustic tomography with magnetic induction (MAT-MI) method. In MAT-MI, the object is placed in a static and a dynamic magnetic field giving rise to ultrasound waves. The dynamic field induces eddy currents in the object, and the static field leads to generation of acoustic vibrations from Lorentz force on the induced currents. The acoustic vibrations are at the same frequency as the dynamic magnetic field, which is chosen to match the ultrasound frequency range. These ultrasound signals can be measured by ultrasound probes and are used to reconstruct MAT-MI acoustic source images using possible ultrasound imaging approaches .The reconstructed high spatial resolution image is indicative of the object's electrical conductivity contrast. We have investigated ultrasound imaging methods to reliably reconstruct the MAT-MI image under the practical conditions of limited bandwidth and transducer geometry. The corresponding imaging algorithm, computer simulation and experiments are developed to test the feasibility of these different methods. Also, in experiments, we have developed a system with the strong static field of an MRI magnet and a strong pulsed magnetic field to evaluate MAT-MI in biological tissue imaging. It can be seen from these simulations and experiments that conductivity boundary images with millimeter resolution can be reliably reconstructed with MAT-MI. Further, to estimate the conductivity distribution throughout the object, we reconstruct a vector source image corresponding to the induced eddy currents. As the current source is uniformly present throughout the object, we are able to reliably estimate the internal conductivity distribution for a more complete imaging. From the computer simulations and experiments it can be seen that MAT-MI method has the potential to be a clinically applicable, high resolution, non-invasive method for electrical conductivity imaging.

Air-Cored Linear Induction Motor for Earth-to-Orbit Systems

NASA Technical Reports Server (NTRS)

Zabar, Zivan; Levi, Enrico; Birenbaum, Leo

1996-01-01

The need for lowering the cost of Earth-to-Orbit (ETO) launches has prompted consideration of electromagnetic launchers. A preliminary design based on the experience gained in an advanced type of coilgun and on innovative ideas shows that such a launcher is technically feasible with almost off-the-shelf components.

Multi-Sensor Systems Development for UXO Detection and Discrimination: Hand-Held Dual Magnetic/Electromagnetic Induction Sensor

DTIC Science & Technology

2008-04-01

5 Fluxgate magnetometer ... magnetometer into digital format, and transmitted as a single serial data string to log the Cs and fluxgate magnetometer data. After procurement...Hardware The system hardware comprises an EMI sensor, Cs vapor magnetometer , fluxgate magnetometer , hand-held data acquisition computer, integrated

Pedemis: A Portable Electromagnetic Induction Sensor with Integrated Positioning

DTIC Science & Technology

2012-04-27

International Society for Optical Engineering 5794(Part I), 346 – 357 (2005). [18] Pasion , L. R., “A unified approach to uxo discrimination using the...B., and O’Neill, K., “Camp butner uxo data inversion and classification using advanced emi models,” (2010). SERDP-MR-1572. [27] Pasion , L., “Uxo

Comparative Demonstration and Evaluation of Classification Technologies: Closed Castner Range, Fort Bliss, Texas

DTIC Science & Technology

2017-01-23

of classification technologies for Munitions Response (MR). This demonstration was designed to evaluate advanced classification methodology at the...advanced electromagnetic induction sensors and static, cued surveys to classify anomalies as either targets of interest (TOI) or non -TOI. Static data...17  5.1  Conceptual Experimental Design

EMI-Sensor Data to Identify Areas of Manure Accumulation on a Feedlot Surface

USDA-ARS?s Scientific Manuscript database

A study was initiated to test the validity of using electromagnetic induction (EMI) survey data, a prediction-based sampling strategy and ordinary linear regression modeling to predict spatially variable feedlot surface manure accumulation. A 30 m × 60 m feedlot pen with a central mound was selecte...

ESTCP Pilot Program. Classification Approaches in Munitions Response, San Luis Obispo, California

DTIC Science & Technology

2010-05-01

geology. Electromagnetic induction sensors detect ferrous and nonferrous metallic objects and can be effective in geology that challenges...34  5.3  Metal Mapper...correspond to munitions, but rather to other harmless metallic objects or geology: field experience indicates that often in excess of 90% of objects

Faraday's Investigation of Electromagnetic Induction. Experiment No. 21.

ERIC Educational Resources Information Center

Devons, Samuel

This paper focuses on Michael Faraday's experimental research in electricity in the 1830's. Historical notes related to his work are included as well as experiments, his objectives, and illustrations of equipment for the experiments. Examples from his diary are given so that students can attempt to emulate his honest and systematic manner of…

If Maxwell Had Worked between Ampere and Faraday: An Historical Fable with a Pedagogical Moral.

ERIC Educational Resources Information Center

Jammer, Max; Stachel, John

1980-01-01

Describes a new pedagogical approach to electromagnetic theory, in which the displacement current and the Galilean relativity principle are introduced before discussion of the Faraday induction term. Rationale for the alternate order of introducing these concepts and laws is explained, relative to their historical development. (CS)

Various Paths to Faraday's Law

ERIC Educational Resources Information Center

Redzic, Dragan V.

2008-01-01

In a recent note, the author presented a derivation of Faraday's law of electromagnetic induction for a closed filamentary circuit C(t) which is moving at relativistic velocities and also changing its shape as it moves via the magnetic vector potential. Recently, Kholmetskii et al, while correcting an error in an equation, showed that it can be…

Borehole geophysical logs at Naval Weapons Industrial Reserve Plant, Dallas, Texas

USGS Publications Warehouse

Braun, Christopher L.; Anaya, Roberto; Kuniansky, Eve L.

2000-01-01

A shallow alluvial aquifer at the Naval Weapons Industrial Reserve Plant near Dallas, Texas, has been contaminated by organic solvents used in the fabrication and assembly of aircraft and aircraft parts. Natural gamma-ray and electromagnetic-induction borehole geophysical logs were obtained from 162 poly vinyl-chloride-cased wells at the plant and were integrated with existing lithologic data to improve site characterization of the subsurface alluvium. Software was developed for filtering and classifying the log data and for processing, analyzing, and creating graphical output of the digital data. The alluvium consists of mostly fine-grained low-permeability sediments; however for this study, the alluvium was classified into low, intermediate, and high clay-content sediments on the basis of the gamma-ray logs. The low clay-content sediments were interpreted as being relatively permeable, whereas the high clay-content sediments were interpreted as being relatively impermeable. Simple statistics were used to identify zones of potentially contaminated sediments on the basis of the gamma-ray log classifications and the electromagnetic-induction log conductivity data.

Electromagnetic heating of minor planets in the early solar system

NASA Technical Reports Server (NTRS)

Herbert, F.; Sonett, C. P.

1979-01-01

Electromagnetic processes occurring in the primordial solar system are likely to have significantly affected planetary evolution. In particular, electrical coupling of the kinetic energy of a dense T-Tauri-like solar wind into the interior of the smaller planets could have been a major driver of thermal metamorphism. Accordingly a grid of asteroid models of various sizes and solar distances was constructed using dc transverse magnetic induction theory. Plausible parameterizations with no requirement for a high environmental temperature led to complete melting for Vesta with no melting for Pallas and Ceres. High temperatures were reached in the Pallas model, perhaps implying nonmelting thermal metamorphosis as a cause of its anomalous spectrum. A reversal of this temperature sequence seems implausible, suggesting that the Ceres-Pallas-Vesta dichotomy is a natural outcome of the induction mechanism. Highly localized heating is expected to arise due to an instability in the temperature-controlled current distribution. Localized metamorphosis resulting from this effect may be relevant to the production and evolution of pallasites, the large presumed metal component of S object spectra, and the formation of the lunar magma ocean.

Geophysical Investigation of Buried Slag at the Parrot Tailings Site, Butte, Montana

NASA Astrophysics Data System (ADS)

Ha, C. D. M.; Shepherd, K.; Mack, A.; Rutherford, B. S.; Speece, M. A.

2016-12-01

Butte, Montana, has served as an important mining district for more than 120 years. This area contains historic mine waste from decades of unregulated mining practices. In July 1881, the Parrot smelter in Butte started operations and was soon processing ore and producing copper. The Parrot smelter also had a concentrating plant that treated the ore prior to smelting. The Parrot smelter wastes (slag and tailings) were later covered with Berkeley Pit crushed quartz monzonite overburden. The slag is bricked because it was deposited hot and, as a consequence forms a laterally extensive, cohesive, hard body that is difficult to remove without blasting. With the mine waste being covered by unknown quantities of overburden and soil throughout the area, and core data being limited and expensive to retrieve, the only economical method of discovery is geophysics. Several geophysical techniques were used to determine the lateral boundaries and depth of the buried slag body. The geophysical methods used were seismic, gravity, electromagnetic induction, and magnetics. Not all of these geophysical surveys produced useful results due to the nature of the slag. For instance, electromagnetic induction could not distinguish between the slag and adjacent tailings; and, the microgravity profiles showed only a small gravitational field variation caused by the density contrast between slag and the surrounding tailings, sediment and granitic cover. On the other hand, the seismic surveys resulted in unexpected first arrival times that distinctly showed velocity variations due to the slag. In addition, the slag body produced a large magnetic response. Unpublished, proprietary well data allowed us to model the slag body from our magnetic data. This model was confirmed by projecting velocity tomograms, that we created using seismic diving waves, onto our magnetic models. Model results were combined to form a three-dimensional image of the slag body. These results will be used to help construct a remediation plan to remove the slag along with the associated tailings.

Using the Electromagnetic Induction Method to Connect Spatial Vegetation Distributions with Soil Water and Salinity Dynamics on Steppe Grassland

NASA Astrophysics Data System (ADS)

Jiang, Z.; Li, X.; Wu, H.

2014-12-01

In arid and semi-arid areas, plant growth and productivity are obviously affected by soil water and salinity. But it is not easy to acquire the spatial and temporal dynamics of soil water and salinity by traditional field methods because of the heterogeneity in their patterns. Electromagnetic induction (EMI), for its rapid character, can provide a useful way to solve this problem. Grassland dominated by Achnatherum splendens is an important ecosystem near the Qinghai-Lake watershed on the Qinghai-Tibet Plateau in northwestern China. EMI surveys were conducted for electrical conductivity (ECa) at an intermediate habitat scale (a 60×60 m experimental area) of A. splendens steppe for 18 times (one day only for one time) during the 2013 growing season. And twenty sampling points were established for the collection of soil samples for soil water and salinity, which were used for calibration of ECa. In addition, plant species, biomass and spatial patterns of vegetation were also sampled. The results showed that ECa maps exhibited distinctly spatial differences because of variations in soil moisture. And soil water was the main factor to drive salinity patterns, which in turn affected ECa values. Moreover, soil water and salinity could explain 82.8% of ECa changes due to there was a significant correlation (P<0.01) between ECa, soil water and salinity. Furthermore, with higher ECa values closer to A. splendens patches at the experimental site, patterns of ECa images showed clearly temporal stability, which were extremely corresponding with the spatial pattern of vegetation. A. splendens patches that accumulated infiltrating water and salinity and thus changed long-term soil properties, which were considered as "reservoirs" and were deemed responsible for the temporal stability of ECa images. Hence, EMI could be an indicator to locate areas of decreasing or increasing of water and to reveal soil water and salinity dynamics through repeated ECa surveys.

Initial Results from Lunar Electromagnetic Sounding with ARTEMIS

NASA Astrophysics Data System (ADS)

Fuqua, H.; Fatemi, S.; Poppe, A. R.; Delory, G. T.; Grimm, R. E.; De Pater, I.

2016-12-01

Electromagnetic Sounding constrains conducting layers of the lunar interior by observing variations in the Interplanetary Magnetic Field. Here, we focus our analysis on the time domain transfer function method locating transient events observed by two magnetometers near the Moon. We analyze ARTEMIS and Apollo magnetometer data. This analysis assumes the induced field responds undisturbed in a vacuum. In actuality, the dynamic plasma environment interacts with the induced field. Our models indicate distortion but not confinement occurs in the nightside wake cavity. Moreover, within the deep wake, near-vacuum region, distortion of the induced dipole fields due to the interaction with the wake is minimal depending on the magnitude of the induced field, the geometry of the upstream fields, and the upstream plasma parameters such as particle densities, solar wind velocity, and temperatures. Our results indicate the assumption of a vacuum dipolar response is reasonable within this minimally disturbed zone. We then interpret the ATEMIS magnetic field signal through a geophysical forward model capturing the induced response based on prescribed electrical conductivity models. We demonstrate our forward model passes benchmarking analyses and solves the magnetic induction response for any input signal as well as any 2 or 3 dimensional conductivity profile. We locate data windows according to the following criteria: (1) probe locations such that the wake probe is within 500km altitude within the wake cavity and minimally disturbed zone, and the second probe is in the free streaming solar wind; (2) a transient event consisting of an abrupt change in the magnetic field occurs enabling the observation of induction; (3) cross correlation analysis reveals the magnetic field signals are well correlated between the two probes and distances observed. Here we present initial ARTEMIS results providing further insight into the lunar interior structure. This method and modeling results are applicable to any airless body with a conducting interior, interacting directly with the solar wind in the absence of a parent body magnetic field as well as any two point magnetometer constellation.

Hall effect in a moving liquid

NASA Astrophysics Data System (ADS)

Di Lieto, Alberto; Giuliano, Alessia; Maccarrone, Francesco; Paffuti, Giampiero

2012-01-01

A simple experiment, suitable for performing in an undergraduate physics laboratory, illustrates electromagnetic induction through the water entering into a cylindrical rubber tube by detecting the voltage developed across the tube in the direction transverse both to the flow velocity and to the magnetic field. The apparatus is a very simple example of an electromagnetic flowmeter, a device which is commonly used both in industrial and physiological techniques. The phenomenology observed is similar to that of the Hall effect in the absence of an electric current in the direction of motion of the carriers. The experimental results show a dependence on the intensity of the magnetic field and on the carrier velocity, in good agreement with the theory. Discussion of the system, based on classical electromagnetism, indicates that the effect depends only on the flow rate, and is independent both of the velocity profile and of the electrical conductivity of the medium.

A general theory of DC electromagnetic launchers

NASA Astrophysics Data System (ADS)

Engel, Thomas G.; Timpson, Erik J.

2015-08-01

The non-linear, transient operation of DC electromagnetic launchers (EMLs) complicates their theoretical understanding and prevents scaling studies and performance comparisons without the aid of detailed numerical models. This paper presents a general theory for DC electromagnetic launchers that has simplified these tasks by identifying critical EML parameters and relationships affecting the EML's voltage, current, and power scaling, as well as its performance and energy conversion efficiency. EML parameters and relationships discussed in this paper include the specific force, the operating mode, the launcher constant, the launcher characteristic velocity, the contact characteristic velocity, the energy conversion efficiency, and the kinetic power and voltage-current scaling relationship. The concepts of the ideal EML, same-scale comparisons, and EML impedance are discussed. This paper defines conditions needed for the EML to operate in the steady-state. A comparison of the general theory with experimental results of several different types of DC (i.e., non-induction) electromagnetic launchers ranging from medium velocity (100's m/s) to high velocity (1000's m/s) is performed. There is good agreement between the general theory and the experimental results.

REVIEWS OF TOPICAL PROBLEMS: "Magnetized" black holes

NASA Astrophysics Data System (ADS)

Aliev, A. N.; Gal'tsov, D. V.

1989-01-01

Physical aspects of the theory of black holes in an external electromagnetic field are reviewed. The "magnetized" black hole model is currently widely discussed in astrophysics because it provides a basis for the explanation of the high energy activity of galactic cores and quasars. The particular feature of this model is that it predicts unusual "gravimagnetic" phenomena that arise as a result of a natural combination of effects in electrodynamics and gravitation, namely, the appearance of an inductive potential difference during the rotation of a black hole in a magnetic field, the drift of a black hole in an external electromagnetic field, the change in the chemical potential of the event horizon, the creation of an effective ergosphere of a black hole in a magnetic field, and so on. Questions relating to the description of electromagnetic fields in Kerr space-time are examined, including their influence on the space-time metric, the interaction between a rotating charged black hole and an external electromagnetic field, the motion of charged particles near "magnetized" black holes, including their spontaneous and stimulated emission, and the influence of magnetic fields on quantum-mechanical processes in black holes.

Influence of extremely low frequency electromagnetic fields on growth performance, innate immune response, biochemical parameters and disease resistance in rainbow trout, Oncorhynchus mykiss.

PubMed

Nofouzi, Katayoon; Sheikhzadeh, Najmeh; Mohamad-Zadeh Jassur, Davood; Ashrafi-Helan, Javad

2015-06-01

The effects of extremely low frequency electromagnetic fields on rainbow trout growth performance, innate immunity and biochemical parameters were studied. Rainbow trout (17-18 g) were exposed to electromagnetic fields (15 Hz) at 0.01, 0.1, 0.5, 5 and 50 µT, for 1 h daily over period of 60 days. Growth performance of fish improved in different treatment groups, especially at 0.1, 0.5, 5 and 50 µT. Immunological parameters, specifically hemagglutinating titer, total antiprotease and α1-antiprotease levels in treatment groups, were also enhanced. Total protein and globulin contents in the serum of fish exposed to 0.1, 0.5, 5 and 50 µT were significantly higher than those in the control group. No significant differences were found in serum enzyme activities, namely aspartate aminotransferase and alanine aminotransferase of fish in all treatment groups. Conversely, alkaline phosphatase level decreased in fish exposed to 0.01 and 50 µT electromagnetic fields. Meanwhile, electromagnetic induction at 0.1, 0.5, 5 and 50 µT enhanced fish protection against Yersinia ruckeri. These results indicated that these specific electromagnetic fields had possible effects on growth performance, nonspecific immunity and disease resistance of rainbow trout.

Design synthesis and optimization of permanent magnet synchronous machines based on computationally-efficient finite element analysis

NASA Astrophysics Data System (ADS)

Sizov, Gennadi Y.

In this dissertation, a model-based multi-objective optimal design of permanent magnet ac machines, supplied by sine-wave current regulated drives, is developed and implemented. The design procedure uses an efficient electromagnetic finite element-based solver to accurately model nonlinear material properties and complex geometric shapes associated with magnetic circuit design. Application of an electromagnetic finite element-based solver allows for accurate computation of intricate performance parameters and characteristics. The first contribution of this dissertation is the development of a rapid computational method that allows accurate and efficient exploration of large multi-dimensional design spaces in search of optimum design(s). The computationally efficient finite element-based approach developed in this work provides a framework of tools that allow rapid analysis of synchronous electric machines operating under steady-state conditions. In the developed modeling approach, major steady-state performance parameters such as, winding flux linkages and voltages, average, cogging and ripple torques, stator core flux densities, core losses, efficiencies and saturated machine winding inductances, are calculated with minimum computational effort. In addition, the method includes means for rapid estimation of distributed stator forces and three-dimensional effects of stator and/or rotor skew on the performance of the machine. The second contribution of this dissertation is the development of the design synthesis and optimization method based on a differential evolution algorithm. The approach relies on the developed finite element-based modeling method for electromagnetic analysis and is able to tackle large-scale multi-objective design problems using modest computational resources. Overall, computational time savings of up to two orders of magnitude are achievable, when compared to current and prevalent state-of-the-art methods. These computational savings allow one to expand the optimization problem to achieve more complex and comprehensive design objectives. The method is used in the design process of several interior permanent magnet industrial motors. The presented case studies demonstrate that the developed finite element-based approach practically eliminates the need for using less accurate analytical and lumped parameter equivalent circuit models for electric machine design optimization. The design process and experimental validation of the case-study machines are detailed in the dissertation.

An Algorithm Framework for Isolating Anomalous Signals in Electromagnetic Data

NASA Astrophysics Data System (ADS)

Kappler, K. N.; Schneider, D.; Bleier, T.; MacLean, L. S.

2016-12-01

QuakeFinder and its international collaborators have installed and currently maintain an array of 165 three-axis induction magnetometer instrument sites in California, Peru, Taiwan, Greece, Chile and Sumatra. Based on research by Bleier et al. (2009), Fraser-Smith et al. (1990), and Freund (2007), the electromagnetic data from these instruments are being analyzed for pre-earthquake signatures. This analysis consists of both private research by QuakeFinder, and institutional collaborators (PUCP in Peru, NCU in Taiwan, NOA in Greece, LASP at University of Colorado, Stanford, UCLA, NASA-ESI, NASA-AMES and USC-CSEP). QuakeFinder has developed an algorithm framework aimed at isolating anomalous signals (pulses) in the time series. Results are presented from an application of this framework to induction-coil magnetometer data. Our data driven approach starts with sliding windows applied to uniformly resampled array data with a variety of lengths and overlap. Data variance (a proxy for energy) is calculated on each window and a short-term average/ long-term average (STA/LTA) filter is applied to the variance time series. Pulse identification is done by flagging time intervals in the STA/LTA filtered time series which exceed a threshold. Flagged time intervals are subsequently fed into a feature extraction program which computes statistical properties of the resampled data. These features are then filtered using a Principal Component Analysis (PCA) based method to cluster similar pulses. We explore the extent to which this approach categorizes pulses with known sources (e.g. cars, lightning, etc.) and the remaining pulses of unknown origin can be analyzed with respect to their relationship with seismicity. We seek a correlation between these daily pulse-counts (with known sources removed) and subsequent (days to weeks) seismic events greater than M5 within 15km radius. Thus we explore functions which map daily pulse-counts to a time series representing the likelihood of a seismic event occurring at some future time. These "pseudo-probabilities" can in turn be represented as Molchan diagrams. The Molchan curve provides an effective cost function for optimization and allows for a rigorous statistical assessment of the validity of pre-earthquake signals in the electromagnetic data.

Development of Numerical Codes for Modeling Electromagnetic Behavior at High Frequencies Near Large Objects

NASA Technical Reports Server (NTRS)

Joshi, R. P.; Deshpande, M. D. (Technical Monitor)

2003-01-01

A study into the problem of determining electromagnetic solutions at high frequencies for problems involving complex geometries, large sizes and multiple sources (e.g. antennas) has been initiated. Typical applications include the behavior of antennas (and radiators) installed on complex conducting structures (e.g. ships, aircrafts, etc..) with strong interactions between antennas, the radiation patterns, and electromagnetic signals is of great interest for electromagnetic compatibility control. This includes the overall performance evaluation and control of all on-board radiating systems, electromagnetic interference, and personnel radiation hazards. Electromagnetic computational capability exists at NASA LaRC, and many of the codes developed are based on the Moment Method (MM). However, the MM is computationally intensive, and this places a limit on the size of objects and structures that can be modeled. Here, two approaches are proposed: (i) a current-based hybrid scheme that combines the MM with Physical optics, and (ii) an Alternating Direction Implicit-Finite Difference Time Domain (ADI-FDTD) method. The essence of a hybrid technique is to split the overall scattering surface(s) into two regions: (a) a MM zone (MMZ) which can be used over any part of the given geometry, but is most essential over irregular and "non-smooth" geometries, and (b) a PO sub-region (POSR). Currents induced on the scattering and reflecting surfaces can then be computed in two ways depending on whether the region belonged to the MMZ or was part of the POSR. For the MMZ, the current calculations proceed in terms of basis functions with undetermined coefficients (as in the usual MM method), and the answer obtained by solving a system of linear equations. Over the POSR, conduction is obtained as a superposition of two contributions: (i) currents due to the incident magnetic field, and (ii) currents produced by the mutual induction from conduction within the MMZ. This effectively leads to a reduction in the size of linear equations from N to N - Npo with N being the total number of segments for the entire surface and Npo the number of segments over the POSR. The scheme would be appropriate for relatively large, flat surfaces, and at high frequencies. The ADI-FDTD scheme provides for both transient and steady state analyses. The restrictive Courant-Friedrich-Levy (CFL) condition on the time-step is removed, and so large time steps can be chosen even though the spatial grids are small. This report includes the problem definition, a detailed discussion of both the numerical techniques, and numerical implementations for simple surface geometries. Numerical solutions have been derived for a few simple situations.

Spatial relationship between the productivity of cane sugar and soil electrical conductivity measured by electromagnetic induction

NASA Astrophysics Data System (ADS)

Siqueira, Glecio; Silva, Jucicléia; Bezerra, Joel; Silva, Enio; Montenegro, Abelardo

2013-04-01

The cultivation of sugar cane in Brazil occupies a prominent place in national production chain, because the country is the main world producer of sugar and ethanol. Accordingly, studies are needed that allow an integrated production and technified, and especially that estimates of crops are consistent with the actual production of each region. The objective of this study was to determine the spatial relationship between the productivity of cane sugar and soil electrical conductivity measured by electromagnetic induction. The field experiment was conducted at an agricultural research site located in Goiana municipality, Pernambuco State, north-east of Brazil (Latitude 07 ° 34 '25 "S, Longitude 34 ° 55' 39" W). The surface of the studied field is 6.5 ha, and its mean height 8.5 m a.s.l. This site has been under sugarcane (Saccharum officinarum sp.) monoculture during the last 24 years and it was managed burning the straw each year after harvesting, renewal of plantation was performed every 7 years. Studied the field is located 10 km east from Atlantic Ocean and it is representative of the regional landscape lowlands, whose soils are affected by salinity seawater, sugarcane plantations with the main economical activity. Soil was classified an orthic the Podsol. The productivity of cane sugar and electrical conductivity were measured in 90 sampling points. The productivity of cane sugar was determined in each of the sampling points in plots of 9 m2. The Apparent soil electrical conductivity (ECa, mS m-1) was measured with an electromagnetic induction device EM38-DD (Geonics Limited). The equipment consists of two units of measurement, one in a horizontal dipole (ECa-H) to provide effective measurement distance of 1.5 m approximately and other one in vertical dipole (ECa-V) with an effective measurement depth of approximately 0.75 m. Data were analyzed using descriptive statistics and geostatistical tools. The results showed that productivity in the study area reached values above 200 t ha-1, with higher values of productivity are concentrated in the region northern terrain. The maps of soil electrical conductivity (ECa-V and ECa-H) showed behavior similar to the productivity of cane sugar. The linear correlation showed values of 0.74 (yield x ECa-H) and 0.85 (yield x ECa-V). The adjusted semivariograms showed no similarity in the spatial pattern of pairs of semivariance. The electrical conductivity measured by electromagnetic induction has been shown as an important tool for predicting the productivity of sugar cane, however more studies are needed to determine the magnitude of the differences between such attributes.

Airborne thickness and freeboard measurements over the McMurdo Ice Shelf, Antarctica, and implications for ice density

NASA Astrophysics Data System (ADS)

Rack, Wolfgang; Haas, Christian; Langhorne, Pat J.

2013-11-01

We present airborne measurements to investigate the thickness of the western McMurdo Ice Shelf in the western Ross Sea, Antarctica. Because of basal accretion of marine ice and brine intrusions conventional radar systems are limited in detecting the ice thickness in this area. In November 2009, we used a helicopter-borne laser and electromagnetic induction sounder (EM bird) to measure several thickness and freeboard profiles across the ice shelf. The maximum electromagnetically detectable ice thickness was about 55 m. Assuming hydrostatic equilibrium, the simultaneous measurement of ice freeboard and thickness was used to derive bulk ice densities ranging from 800 to 975 kg m-3. Densities higher than those of pure ice can be largely explained by the abundance of sediments accumulated at the surface and present within the ice shelf, and are likely to a smaller extent related to the overestimation of ice thickness by the electromagnetic induction measurement related to the presence of a subice platelet layer. The equivalent thickness of debris at a density of 2800 kg m-3 is found to be up to about 2 m thick. A subice platelet layer below the ice shelf, similar to what is observed in front of the ice shelf below the sea ice, is likely to exist in areas of highest thickness. The thickness and density distribution reflects a picture of areas of basal freezing and supercooled Ice Shelf Water emerging from below the central ice shelf cavity into McMurdo Sound.

Circuit models and three-dimensional electromagnetic simulations of a 1-MA linear transformer driver stage

NASA Astrophysics Data System (ADS)

Rose, D. V.; Miller, C. L.; Welch, D. R.; Clark, R. E.; Madrid, E. A.; Mostrom, C. B.; Stygar, W. A.; Lechien, K. R.; Mazarakis, M. A.; Langston, W. L.; Porter, J. L.; Woodworth, J. R.

2010-09-01

A 3D fully electromagnetic (EM) model of the principal pulsed-power components of a high-current linear transformer driver (LTD) has been developed. LTD systems are a relatively new modular and compact pulsed-power technology based on high-energy density capacitors and low-inductance switches located within a linear-induction cavity. We model 1-MA, 100-kV, 100-ns rise-time LTD cavities [A. A. Kim , Phys. Rev. ST Accel. Beams 12, 050402 (2009)PRABFM1098-440210.1103/PhysRevSTAB.12.050402] which can be used to drive z-pinch and material dynamics experiments. The model simulates the generation and propagation of electromagnetic power from individual capacitors and triggered gas switches to a radially symmetric output line. Multiple cavities, combined to provide voltage addition, drive a water-filled coaxial transmission line. A 3D fully EM model of a single 1-MA 100-kV LTD cavity driving a simple resistive load is presented and compared to electrical measurements. A new model of the current loss through the ferromagnetic cores is developed for use both in circuit representations of an LTD cavity and in the 3D EM simulations. Good agreement between the measured core current, a simple circuit model, and the 3D simulation model is obtained. A 3D EM model of an idealized ten-cavity LTD accelerator is also developed. The model results demonstrate efficient voltage addition when driving a matched impedance load, in good agreement with an idealized circuit model.

An Assessment of Hazards Caused by Electromagnetic Interaction on Humans Present near Short-Wave Physiotherapeutic Devices of Various Types Including Hazards for Users of Electronic Active Implantable Medical Devices (AIMD)

PubMed Central

Gryz, Krzysztof

2013-01-01

Leakage of electromagnetic fields (EMF) from short-wave radiofrequency physiotherapeutic diathermies (SWDs) may cause health and safety hazards affecting unintentionally exposed workers (W) or general public (GP) members (assisting patient exposed during treatment or presenting there for other reasons). Increasing use of electronic active implantable medical devices (AIMDs), by patients, attendants, and workers, needs attention because dysfunctions of these devices may be caused by electromagnetic interactions. EMF emitted by 12 SWDs (with capacitive or inductive applicators) were assessed following international guidelines on protection against EMF exposure (International Commission on Nonionizing Radiation Protection for GP and W, new European directive 2013/35/EU for W, European Recommendation for GP, and European Standard EN 50527-1 for AIMD users). Direct EMF hazards for humans near inductive applicators were identified at a distance not exceeding 45 cm for W or 62 cm for GP, but for AIMD users up to 90 cm (twice longer than that for W and 50% longer than that for GP because EMF is pulsed modulated). Near capacitive applicators emitting continuous wave, the corresponding distances were: 120 cm for W or 150 cm for both—GP or AIMD users. This assessment does not cover patients who undergo SWD treatment (but it is usually recommended for AIMD users to be careful with EMF treatment). PMID:24089662

Imaging cerebral haemorrhage with magnetic induction tomography: numerical modelling.

PubMed

Zolgharni, M; Ledger, P D; Armitage, D W; Holder, D S; Griffiths, H

2009-06-01

Magnetic induction tomography (MIT) is a new electromagnetic imaging modality which has the potential to image changes in the electrical conductivity of the brain due to different pathologies. In this study the feasibility of detecting haemorrhagic cerebral stroke with a 16-channel MIT system operating at 10 MHz was investigated. The finite-element method combined with a realistic, multi-layer, head model comprising 12 different tissues, was used for the simulations in the commercial FE package, Comsol Multiphysics. The eddy-current problem was solved and the MIT signals computed for strokes of different volumes occurring at different locations in the brain. The results revealed that a large, peripheral stroke (volume 49 cm(3)) produced phase changes that would be detectable with our currently achievable instrumentation phase noise level (17 m degrees ) in 70 (27%) of the 256 exciter/sensor channel combinations. However, reconstructed images showed that a lower noise level than this, of 1 m degrees , was necessary to obtain good visualization of the strokes. The simulated MIT measurements were compared with those from an independent transmission-line-matrix model in order to give confidence in the results.

Study on coupled shock absorber system using four electromagnetic dampers

NASA Astrophysics Data System (ADS)

Fukumori, Y.; Hayashi, R.; Okano, H.; Suda, Y.; Nakano, K.

2016-09-01

Recently, the electromagnetic damper, which is composed of an electric motor, a ball screw, and a nut, was proposed. The electromagnetic damper has high responsiveness, controllability, and energy saving performance. It has been reported that it improved ride comfort and drivability. In addition, the authors have proposed a coupling method of two electromagnetic dampers. The method enables the characteristics of bouncing and rolling or pitching motion of a vehicle to be tuned independently. In this study, the authors increase the number of coupling of electromagnetic dampers from two to four, and propose a method to couple four electromagnetic dampers. The proposed method enables the characteristics of bouncing, rolling and pitching motion of a vehicle to be tuned independently. Basic experiments using proposed circuit and motors and numerical simulations of an automobile equipped with the proposed coupling electromagnetic damper are carried out. The results indicate the proposed method is effective.

Assessment of multi-frequency electromagnetic induction for determining soil moisture patterns at the hillslope scale

NASA Astrophysics Data System (ADS)

Tromp-van Meerveld, H. J.; McDonnell, J. J.

2009-04-01

SummaryHillslopes are fundamental landscape units, yet represent a difficult scale for measurements as they are well-beyond our traditional point-scale techniques. Here we present an assessment of electromagnetic induction (EM) as a potential rapid and non-invasive method to map soil moisture patterns at the hillslope scale. We test the new multi-frequency GEM-300 for spatially distributed soil moisture measurements at the well-instrumented Panola hillslope. EM-based apparent conductivity measurements were linearly related to soil moisture measured with the Aqua-pro capacitance sensor below a threshold conductivity and represented the temporal patterns in soil moisture well. During spring rainfall events that wetted only the surface soil layers the apparent conductivity measurements explained the soil moisture dynamics at depth better than the surface soil moisture dynamics. All four EM frequencies (7.290, 9.090, 11.250, and 14.010 kHz) were highly correlated and linearly related to each other and could be used to predict soil moisture. This limited our ability to use the four different EM frequencies to obtain a soil moisture profile with depth. The apparent conductivity patterns represented the observed spatial soil moisture patterns well when the individually fitted relationships between measured soil moisture and apparent conductivity were used for each measurement point. However, when the same (master) relationship was used for all measurement locations, the soil moisture patterns were smoothed and did not resemble the observed soil moisture patterns very well. In addition the range in calculated soil moisture values was reduced compared to observed soil moisture. Part of the smoothing was likely due to the much larger measurement area of the GEM-300 compared to the soil moisture measurements.

Determining if an axially rotated solenoid will induce a radial EMF

NASA Astrophysics Data System (ADS)

MacDermott, Dustin R.

The nature of the electromagnetic field of an axially rotated solenoid or magnet is investigated. The investigations reviewed suggest the possibility of a radially emitted electric field by either: axially rotated magnetic field lines, or a relativistic change in charge of the electron. For a very long solenoid a relativistic change in charge leaves no electric field inside while leaving an electric field outside. The concept of axially rotating magnetic field lines gives an opposite prediction. They both seem to be in contradiction to the standard model of induction, which gives no change in the electric field for a rotated solenoid or magnet. An experiment by Joseph B. Tate [48], [49] conducted in 1968 seemed to have measured a change in charge outside of a rotated solenoid. Another experiment by Barnett [3] in 1912 reported measuring no electric field inside of a rotated solenoid. Further experimentation was decided necessary and the method decided upon to attempt detection of the radial E or EMF induced by an axially rotating B field or change in charge is two concentric capacitor plates, one inside and the other outside an axially rotated solenoid. The solenoid was rotated on a lathe for the test. A concentric capacitor around an axially rotated permanent neodymium magnet was also used as a test. These experiments proved very challenging because of the small magnitude of the predicted effect. Nevertheless, the bulk of the evidence obtained indicates that no induced E arises when a magnetic source is rotated about its magnetic axis, thus supporting the standard field model of electromagnetic induction, and casting doubt on the alternative theories of magnetic field line rotation or relativistic charge enhancement.

Impact evaluation of conducted UWB transients on loads in power-line networks

NASA Astrophysics Data System (ADS)

Li, Bing; Månsson, Daniel

2017-09-01

Nowadays, faced with the ever-increasing dependence on diverse electronic devices and systems, the proliferation of potential electromagnetic interference (EMI) becomes a critical threat for reliable operation. A typical issue is the electronics working reliably in power-line networks when exposed to electromagnetic environment. In this paper, we consider a conducted ultra-wideband (UWB) disturbance, as an example of intentional electromagnetic interference (IEMI) source, and perform the impact evaluation at the loads in a network. With the aid of fast Fourier transform (FFT), the UWB transient is characterized in the frequency domain. Based on a modified Baum-Liu-Tesche (BLT) method, the EMI received at the loads, with complex impedance, is computed. Through inverse FFT (IFFT), we obtain time-domain responses of the loads. To evaluate the impact on loads, we employ five common, but important quantifiers, i.e., time-domain peak, total signal energy, peak signal power, peak time rate of change and peak time integral of the pulse. Moreover, to perform a comprehensive analysis, we also investigate the effects of the attributes (capacitive, resistive, or inductive) of other loads connected to the network, the rise time and pulse width of the UWB transient, and the lengths of power lines. It is seen that, for the loads distributed in a network, the impact evaluation of IEMI should be based on the characteristics of the IEMI source, and the network features, such as load impedances, layout, and characteristics of cables.

Finite Element Modeling of the Bulk Magnitization of Railroad Wheels to Improve Test Conditions for Magnetoacoustic Residual Stress Measurements

NASA Technical Reports Server (NTRS)

Fulton, J. P.; Wincheski, B.; Namkung, M.; Utrata, D.

1992-01-01

The magnetoacoustic measurement technique has been used successfully for residual stress measurements in laboratory samples. However, when used to field test samples with complex geometries, such as railroad wheels, the sensitivity of the method declines dramatically. It has been suggested that the decrease in performance may be due, in part, to an insufficient or nonuniform magnetic induction in the test sample. The purpose of this paper is to optimize the test conditions by using finite element modeling to predict the distribution of the induced bulk magnetization of railroad wheels. The results suggest that it is possible to obtain a sufficiently large and uniform bulk magnetization by altering the shape of the electromagnet used in the tests. Consequently, problems associated with bulk magnetization can be overcome, and should not prohibit the magnetoacoustic technique from being used to make residual stress measurements in railroad wheels. We begin by giving a brief overview of the magnetoacoustic technique as it applies to residual stress measurements of railroad wheels. We then define the finite element model used to predict the behavior of the current test configuration along with the nonlinear constitutive relations which we obtained experimentally through measurements on materials typically used to construct both railroad wheels and electromagnets. Finally, we show that by modifying the pole of the electromagnet it is possible to obtain a significantly more uniform bulk magnetization in the region of interest.

Effect of electromagnetic radiation on the coils used in aneurysm embolization.

PubMed

Lv, Xianli; Wu, Zhongxue; Li, Youxiang

2014-06-01

This study evaluated the effects of electromagnetic radiation in our daily lives on the coils used in aneurysm embolization. Faraday's electromagnetic induction principle was applied to analyze the effects of electromagnetic radiation on the coils used in aneurysm embolization. To induce a current of 0.5mA in less than 5 mm platinum coils required to stimulate peripheral nerves, the minimum magnetic field will be 0.86 μT. To induce a current of 0.5 mA in platinum coils by a hair dryer, the minimum aneurysm radius is 2.5 mm (5 mm aneurysm). To induce a current of 0.5 mA in platinum coils by a computer or TV, the minimum aneurysm radius is 8.6 mm (approximate 17 mm aneurysm). The minimum magnetic field is much larger than the flux densities produced by computer and TV, while the minimum aneurysm radius is much larger than most aneurysm sizes to levels produced by computer and TV. At present, the effects of electromagnetic radiation in our daily lives on intracranial coils do not produce a harmful reaction. Patients with coiled aneurysm are advised to avoid using hair dryers. This theory needs to be proved by further detailed complex investigations. Doctors should give patients additional instructions before the procedure, depending on this study.

Effect of Electromagnetic Radiation on the Coils Used in Aneurysm Embolization

PubMed Central

Lv, Xianli; Wu, Zhongxue; Li, Youxiang

2014-01-01

Summary This study evaluated the effects of electromagnetic radiation in our daily lives on the coils used in aneurysm embolization. Faraday’s electromagnetic induction principle was applied to analyze the effects of electromagnetic radiation on the coils used in aneurysm embolization. To induce a current of 0.5mA in less than 5 mm platinum coils required to stimulate peripheral nerves, the minimum magnetic field will be 0.86 μT. To induce a current of 0.5 mA in platinum coils by a hair dryer, the minimum aneurysm radius is 2.5 mm (5 mm aneurysm). To induce a current of 0.5 mA in platinum coils by a computer or TV, the minimum aneurysm radius is 8.6 mm (approximate 17 mm aneurysm). The minimum magnetic field is much larger than the flux densities produced by computer and TV, while the minimum aneurysm radius is much larger than most aneurysm sizes to levels produced by computer and TV. At present, the effects of electromagnetic radiation in our daily lives on intracranial coils do not produce a harmful reaction. Patients with coiled aneurysm are advised to avoid using hair dryers. This theory needs to be proved by further detailed complex investigations. Doctors should give patients additional instructions before the procedure, depending on this study. PMID:24976203

A tightly coupled non-equilibrium model for inductively coupled radio-frequency plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Munafò, A., E-mail: munafo@illinois.edu; Alfuhaid, S. A., E-mail: alfuhai2@illinois.edu; Panesi, M., E-mail: mpanesi@illinois.edu

2015-10-07

The objective of the present work is the development of a tightly coupled magneto-hydrodynamic model for inductively coupled radio-frequency plasmas. Non Local Thermodynamic Equilibrium (NLTE) effects are described based on a hybrid State-to-State approach. A multi-temperature formulation is used to account for thermal non-equilibrium between translation of heavy-particles and vibration of molecules. Excited electronic states of atoms are instead treated as separate pseudo-species, allowing for non-Boltzmann distributions of their populations. Free-electrons are assumed Maxwellian at their own temperature. The governing equations for the electro-magnetic field and the gas properties (e.g., chemical composition and temperatures) are written as a coupled systemmore » of time-dependent conservation laws. Steady-state solutions are obtained by means of an implicit Finite Volume method. The results obtained in both LTE and NLTE conditions over a broad spectrum of operating conditions demonstrate the robustness of the proposed coupled numerical method. The analysis of chemical composition and temperature distributions along the torch radius shows that: (i) the use of the LTE assumption may lead to an inaccurate prediction of the thermo-chemical state of the gas, and (ii) non-equilibrium phenomena play a significant role close the walls, due to the combined effects of Ohmic heating and macroscopic gradients.« less

The detection of chronic cerebral hemorrhage in rabbits with magnetic induction

NASA Astrophysics Data System (ADS)

Sun, Jian; Jin, Gui; Qin, Mingxin; Wan, Zibing; Wang, Jinbao; ChaoWang; Guo, Wanyou; Xu, Lin; Ning, Xu; Xu, Jia; Pu, Xianjie; Chen, Mingsheng; Zhao, Hongmei

2012-12-01

Chronic cerebral hemorrhage (CCH) in the brain is an important clinical problem that is often monitored and studied with expensive devices such as MRI and PET, which are not readily available in low economical resource parts of the world. We have developed a less expensive tool for non-contact monitoring of CCH in the brain. The system measures the phase shift between the electromagnetic signals on the two coils. CCH was induced in the brain of rabbits by stereotactic method. Intracranial pressure (ICP) and Electrocardiograph (ECG) of subjects were monitored for 1.5h. Signals were continuously monitored up to t=1.5h at exciting frequency 10.7MHz. From 0.8 to 2.4 ml of autologous blood was injected (each injection quantity of 0.8 ml, the interval time for 30 minutes). The results show significant phase shifts increase as a function of injection volume. ICP and phase shift were directly proportional to the related, while HRV were stable around 200beats*min-1. Our system has high sensitivity that even 0.8 ml can also be detected. In this study, the curves of inductive phase shift are significantly related to ICP. This observation suggests that the method could be valuable, in addition to continuous monitoring, also for early warning in emergency medicine and critical care units.

Integrated induction coil and fluxgate magnetometers for EM analysis and monitoring

NASA Astrophysics Data System (ADS)

Hanstein, T.; Strack, K.; Jiang, J.

2013-12-01

The concept of a full field array electromagnetic system is an ideal tool to support hydrocarbon and geothermal E & P as well as various engineering monitoring applications. Some of the key questions are defining the reservoir, mapping of the fractures and reservoir depletion monitoring. The reservoirs are all too often relative thin and give an anomalous electromagnetic (EM) response, which is often small in amplitude and challenging for the EM measuring system. A digital fluxgate magnetometer (32-bit) is connected to the KMS magnetotelluric acquisition system with analogue induction coils and electrodes to extend the range of application of a single recording site. Since the noise level is above that of the induction coil for periods shorter than 20 s, the apparent resistivity is biased. For longer periods the apparent resistivity is consistent and eventually better than the induction coil. However, phase and tipper are not biased and agree well with the induction data even for shorter periods. This allows us to develop algorithms that significantly extend the range of application of the fluxgate beyond what was done in the past. The highest frequency of the fluxgate magnetometer is about 180 Hz and the hightest sampling of the FG-board is 4 kHz.The different induction coils and fluxgate magnetometer have intensively been tested in the magnetic chamber and at the field test site near Houston for noise performance by parallel recordings. They show that even in an environment with high cultural noise, the specification can be met. In Northeast China, a 30-day monitoring test with MT was carried out for seismologic applications. Acquisitition schedule included different recordings times and sampling rates. Daily, the data was collected and processed via the internet from either Europe or the US. Even with long recording, we still had to select the time windows for data averaging and coherences are not a good threshhold criteria in this case. During another MT sounding in India, an earthquake with magnitude 5 at a distance of about 200 km was recorded. The event is very strong in amplitude and visible in all magnetic and electric field components.

Demonstration of an Enhanced Vertical Magnetic Gradient System for UXO

DTIC Science & Technology

2008-12-01

fluxgate magnetometers , data recording console, laser altimeter, and acoustic altimeters were tested to ensure proper operation and performance. The VG...Simultaneous Electromagnetic Induction and Magnetometer System WAA wide area assessment ACKNOWLEDGEMENTS We wish to express our sincere...sensors. The benefits of vertical gradient (VG) configurations in magnetometer systems are common knowledge, and these configurations are routinely

Multi-Sensor Systems Development for UXO Detection and Discrimination: Man-Portable Dual Magnetic/Electromagnetic Induction Sensor

DTIC Science & Technology

2008-02-01

of the magnetic data to constrain the target depth using joint or cooperative inversions ( Pasion et al. 2002). ERDC/EL TR-08-9 24 Figure 15. EM...baseline ordnance classification test site at Blossom Pt. Naval Research Laboratory. NRL/MR/6110-00-8437, March 20, 1998. Pasion , L., S. Billings, and

Module Two: Voltage; Basic Electricity and Electronics Individualized Learning System.

ERIC Educational Resources Information Center

Bureau of Naval Personnel, Washington, DC.

In this module the student will study and learn what voltage is, how it is generated, what AC (alternating current) and DC (direct current) are and why both kinds are needed, and how to measure voltages. The module is divided into six lessons: EMF (electromotive force) from chemical action, magnetism, electromagnetic induction, AC voltage, the…

Students' Conceptual Change in Electricity and Magnetism Using Simulations: A Comparison of Cognitive Perturbation and Cognitive Conflict

ERIC Educational Resources Information Center

Dega, Bekele Gashe; Kriek, Jeanne; Mogese, Temesgen Fereja

2013-01-01

The purpose of this study was to investigate Ethiopian physics undergraduate students' conceptual change in the concepts of electric potential and energy (EPE) and electromagnetic induction (EMI). A quasi-experimental design was used to study the effect of cognitive perturbation using physics interactive simulations (CPS) in relation to cognitive…

Vector Potential, Electromagnetic Induction and "Physical Meaning"

ERIC Educational Resources Information Center

Giuliani, G.

2010-01-01

A forgotten experiment by Andre Blondel (1914) proves, as held on the basis of theoretical arguments in a previous paper, that the time variation of the magnetic flux is not the cause of the induced emf; the physical agent is instead the vector potential through the term [equation omitted] (when the induced circuit is at rest). The "good…

Electromagnetic Induction with Neodymium Magnets

ERIC Educational Resources Information Center

Wood, Deborah; Sebranek, John

2013-01-01

In April 1820, Hans Christian Ørsted noticed that the needle of a nearby compass deflected briefly from magnetic north each time the electric current of the battery he was using for an unrelated experiment was turned on or off. Upon further investigation, he showed that an electric current flowing through a wire produces a magnetic field. In 1831…

High frequency electromagnetic impedance measurements for characterization, monitoring and verification efforts. 1998 annual progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, K.H.; Pellerin, L.; Becker, A.

1998-06-01

'Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic measurements at frequencies between 1 and 100 MHz are important for such applications, because the induction number of many targets is small due, and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high resolution imaging, accurate measurements are necessary so the field datamore » can be mapped into the space of the subsurface parameters. The authors are developing a non-invasive method for accurately imaging the electrical conductivity and dielectric permittivity of the shallow subsurface using the plane wave impedance approach, known as the magnetotelluric (MT) method at low frequencies. Electric and magnetic sensors are being tested in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques. The summary of the work to date is divided into three sections: equipment procurement, instrumentation, and theoretical developments. For most earth materials, the frequency range from 1 to 100 MHz encompasses a very difficult transition zone between the wave propagation of displacement currents and the diffusive behavior of conduction currents. Test equipment, such as signal generators and amplifiers, does not cover the entire range except at great expense. Hence the authors have divided the range of investigation into three sub-ranges: 1--10 MHz, 10--30 MHz, and 30--100 MHz. Results to date are in the lowest frequency range of 1--10 MHz. Even though conduction currents dominate in this range, as in traditional electromagnetic exploration methods, little work has been done by the geophysical community above 500 kHz.'« less

Fabrication and test of a space power boiler feed electromagnetic pump. Part 1: Design and manufacture of pump

NASA Technical Reports Server (NTRS)

Gahan, J. W.; Powell, A. H.; Pileggi, P. T.; Thompson, S. P.

1972-01-01

A three-phase helical induction electromagnetic (EM) pump has been designed and built. This pump was designed for use as the boiler-feed pump of a potassium Rankine-cycle space electric power system. The pump is constructed of high temperature materials including a T-111 duct, Hiperco 27 magnetic material, nickel clad silver conductor wire, and a completely inorganic insulation system. The pump is designed to deliver 3.25 lb/sec potassium at 1000 F with a developed head of 240 psi while being cooled by 800 F NaK. At these conditions, the overall pump efficiency is expected to be 18%.

A current-carrying coil design with improved liquid cooling arrangement

NASA Astrophysics Data System (ADS)

Ricci, Leonardo; Martini, Luca Matteo; Franchi, Matteo; Bertoldi, Andrea

2013-06-01

The design of an electromagnet requires the compliance with a number of constraints such as power supply characteristics, coil inductance and resistance, and, above all, heat dissipation, which poses the limit to the maximum achievable magnetic field. A common solution consists in using copper tubes in which a coolant flows. This approach, however, introduces further hydrodynamic concerns. To overcome these difficulties, we developed a new kind of electromagnet in which the pipe concept is replaced by a duct formed by the windings. Here we report on the realization and characterization of a compact model system in which the conductors carry a current that is one order of magnitude higher than the current allowable with conventional designs.

Liquid Metal Pump Technologies for Nuclear Surface Power

NASA Technical Reports Server (NTRS)

Polzin, Kurt A.

2007-01-01

Multiple liquid metal pump options are reviewed for the purpose of determining the technologies that are best suited for inclusion in a nuclear reactor thermal simulator intended to rest prototypical space nuclear surface power system components. Conduction, induction and thermoelectric electromagnetic pumps are evaluated based on their performance characteristics and the technical issues associated with incorporation into a reactor system. A thermoelectric electromagnetic pump is selected as the best option for use in NASA-MSFC's Fission Surface Power-Primary Test Circuit reactor simulator based on its relative simplicity, low power supply mass penalty, flight heritage, and the promise of increased pump efficiency over those earlier pump designs through the use of skutterudite thermoelectric elements.

Electromagnetic containerless undercooling facility and experiments for the Shuttle

NASA Technical Reports Server (NTRS)

Frost, R. T.; Flemings, M. C.; Szekely, J.; El-Kaddah, N.; Shiohara, Y.

1984-01-01

An electromagnetic furnace is being prepared for flights aboard the Space Shuttle. This apparatus is capable of melting metals and alloys up to 1400 C melting point by induction heating with subsequent solidification of the freely levitated melt without contact with any container. The solidification can be carried out with greatly reduced fields resulting in minimal heating and stirring of the free melt. Sequential specimens can be processed during flight. Several experiments are planned for a series of flights, beginning in 1985 with an undercooling experiment of NiSn alloys. These will be interspersed with detailed studies of fluid flow caused by low and high field levels in order to quantify the corresponding effect upon the solidification process.

Possible application of electromagnetic guns to impact fusion

NASA Astrophysics Data System (ADS)

Kostoff, R. N.; Peaslee, A. T., Jr.; Ribe, F. L.

1982-01-01

The possible application of electromagnetic guns to impact fusion for the generation of electric power is discussed, and advantages of impact fusion over the more conventional inertial confinement fusion concepts are examined. It is shown that impact fusion can achieve the necessary high yields, of the order of a few gigajoules, which are difficult to achieve with lasers except at unrealistically high target gains. The rail gun accelerator is well adapted to the delivery of some 10-100 megajoules of energy to the fusion target, and the electrical technology involved is relatively simple: inductive storage or rotating machinery and capacitors. It is concluded that the rail gun has the potential of developing into an impact fusion macroparticle accelerator.

Motional Induction by Tsunamis and Ocean Tides: 10 Years of Progress

NASA Astrophysics Data System (ADS)

Minami, Takuto

2017-09-01

Motional induction is the process by which the motion of conductive seawater in the ambient geomagnetic main field generates electromagnetic (EM) variations, which are observable on land, at the seafloor, and sometimes at satellite altitudes. Recent years have seen notable progress in our understanding of motional induction associated with tsunamis and with ocean tides. New studies of tsunami motional induction were triggered by the 2004 Sumatra earthquake tsunami and further promoted by subsequent events, such as the 2010 Chile earthquake and the 2011 Tohoku earthquake. These events yielded observations of tsunami-generated EM variations from land and seafloor stations. Studies of magnetic fields generated by ocean tides attracted interest when the Swarm satellite constellation enabled researchers to monitor tide-generated magnetic variations from low Earth orbit. Both avenues of research benefited from the advent of sophisticated seafloor instruments, by which we may exploit motional induction for novel applications. For example, seafloor EM measurements can serve as detectors of vector properties of tsunamis, and seafloor EM data related to ocean tides have proved useful for sounding Earth's deep interior. This paper reviews and discusses the progress made in motional induction studies associated with tsunamis and ocean tides during the last decade.

Detection of contaminant plumes by bore­ hole geophysical logging

USGS Publications Warehouse

Mack, Thomas J.

1993-01-01

Two borehole geophysical methods—electromagnetic induction and natural gamma radiation logs—were used to vertically delineate landfill leachate plumes in a glacial aquifer. Geophysical logs of monitoring wells near two land-fills in a glacial aquifer in west-central Vermont show that borehole geophysical methods can aid in interpretation of geologic logs and placement of monitoring well screens to sample landfill leachate plumes.Zones of high electrical conductance were delineated from the electromagnetic log in wells near two landfills. Some of these zones were found to correlate with silt and clay units on the basis of drilling and gamma logs. Monitoring wells were screened specifically in zones of high electrical conductivity that did not correlate to a silt or clay unit. Zones of high electrical conductivity that did not correlate to a silt or clay unit were caused by the presence of ground water with a high specific conductance, generally from 1000 to 2370 μS/cm (microsiemens per centimeter at 25 degrees Celsius). Ambient ground water in the study area has a specific conductance of approximately 200 to 400 μS/cm. Landfill leachate plumes were found to be approximately 5 to 20 feet thick and to be near the water table surface.

An electrical bio-chip to transfer and detect electromagnetic stimulation on the cells based on vertically aligned carbon nanotubes.

PubMed

Rafizadeh-Tafti, Saeed; Haqiqatkhah, Mohammad Hossein; Saviz, Mehrdad; Janmaleki, Mohsen; Faraji Dana, Reza; Zanganeh, Somayeh; Abdolahad, Mohammad

2017-01-01

A highly sensitive impedimetric bio-chip based on vertically aligned multiwall carbon nanotubes (VAMWCNTs), was applied in direct interaction with lung cancer cells. Our tool provided both inducing and monitoring the bioelectrical changes in the cells initiated by electromagnetic (EM) wave stimulation. EM wave of 940MHz frequency with different intensities was used. Here, wave ablation might accumulate electrical charge on the tips of nanotubes penetrated into cell's membrane. The charge might induce ionic exchanges into the cell and cause alterations in electrical states of the membrane. Transmembrane electrostatic/dynamic states would be strongly affected due to such exchanges. Our novel modality was that, the cells' vitality changes caused by charge inductions were electrically detected with the same nanotubes in the architecture of electrodes for impedance measurement. The responses of the sensor were confirmed by electron and florescent microscopy images as well as biological assays. In summation, our method provided an effective biochip for enhancing and detecting external EM stimulation on the cells useful for future diagnostic and therapeutic applications, such as wave-guided drug-resistance breakage. Copyright © 2016 Elsevier B.V. All rights reserved.

High-Frequency Electromagnetic Impedance Measurements for Characterization, Monitoring and Verification Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ki Ha; Becker, Alex; Tseng, Hung-Wen

2004-06-16

Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic (EM) measurements at frequencies between 0.1 and 100 MHz are important for such applications, because the induction number of many targets is small and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high-resolution imaging, accurate measurements are necessary so the field data canmore » be mapped into the space of the subsurface parameters. We are developing a non-invasive method for accurately mapping the electrical conductivity and dielectric permittivity of the shallow subsurface using the EM impedance approach (Frangos, 2001; Lee and Becker, 2001; Song et al., 2002, Tseng et al., 2003). Electric and magnetic sensors are being tested and calibrated on sea water and in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques.« less

Electromagnetic disturbance of electric drive system signal is extracted based on PLS

NASA Astrophysics Data System (ADS)

Wang, Yun; Wang, Chuanqi; Yang, Weidong; Zhang, Xu; Jiang, Li; Hou, Shuai; Chen, Xichen

2018-05-01

At present ISO11452 and GB/T33014 specified by electromagnetic immunity are narrowband electromagnetic radiation, but our exposure to electromagnetic radiation at ordinary times is not only a narrowband electromagnetic radiation, and some broadband electromagnetic radiation, and even some of the more complex electromagnetic environment. In terms of Electric vehicles, electric drive system is a kind of complex electromagnetic disturbance source, is not only a narrow-band signal, there are a lot of broadband signal, this paper puts forward PLS data processing method is adopted to analyze the electric drive system of electromagnetic disturbance, this kind of method to extract the data can be provide reliable data support for future standards.

Average value of the shape and direction factor in the equation of refractive index

NASA Astrophysics Data System (ADS)

Zhang, Tao

2017-10-01

The theoretical calculation of the refractive indices is of great significance for the developments of new optical materials. The calculation method of refractive index, which was deduced from the electron-cloud-conductor model, contains the shape and direction factor 〈g〉. 〈g〉 affects the electromagnetic-induction energy absorbed by the electron clouds, thereby influencing the refractive indices. It is not yet known how to calculate 〈g〉 value of non-spherical electron clouds. In this paper, 〈g〉 value is derived by imaginatively dividing the electron cloud into numerous little volume elements and then regrouping them. This paper proves that 〈g〉 = 2/3 when molecules’ spatial orientations distribute randomly. The calculations of the refractive indices of several substances validate this equation. This result will help to promote the application of the calculation method of refractive index.

Simulation of superconducting tapes and coils with convex quadratic programming method

NASA Astrophysics Data System (ADS)

Zhang, Yan; Song, Yuntao; Wang, Lei; Liu, Xufeng

2015-08-01

Second-generation (2G) high-temperature superconducting coated conductors are playing an increasingly important role in power applications due to their large current density under high magnetic fields. In this paper, we conclude and explore the ability and possible potential of J formulation from the mathematical modeling point of view. An equivalent matrix form of J formulation has been presented and a relation between electromagnetic quantities and Karush-Kuhn-Tucker (KKT) conditions in optimization theory has been discovered. The use of the latest formulae to calculate inductance in a coil system and the primal-dual interior-point method algorithm is a trial to make the process of modeling stylized and build a bridge to commercial optimization solvers. Two different dependences of the critical current density on the magnetic field have been used in order to make a comparison with those published papers.

Design and manufacture of a D-shape coil-based toroid-type HTS DC reactor using 2nd generation HTS wire

NASA Astrophysics Data System (ADS)

Kim, Kwangmin; Go, Byeong-Soo; Sung, Hae-Jin; Park, Hea-chul; Kim, Seokho; Lee, Sangjin; Jin, Yoon-Su; Oh, Yunsang; Park, Minwon; Yu, In-Keun

2014-09-01

This paper describes the design specifications and performance of a real toroid-type high temperature superconducting (HTS) DC reactor. The HTS DC reactor was designed using 2G HTS wires. The HTS coils of the toroid-type DC reactor magnet were made in the form of a D-shape. The target inductance of the HTS DC reactor was 400 mH. The expected operating temperature was under 20 K. The electromagnetic performance of the toroid-type HTS DC reactor magnet was analyzed using the finite element method program. A conduction cooling method was adopted for reactor magnet cooling. Performances of the toroid-type HTS DC reactor were analyzed through experiments conducted under the steady-state and charge conditions. The fundamental design specifications and the data obtained from this research will be applied to the design of a commercial-type HTS DC reactor.

Experience of ALCOA-KOFEM with MHD induction stirrer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petho, S.

1996-10-01

Every ingot cast shop makes an effort to reduce the costs and to increase the productivity. The MHD stirrer is an adequate tool to achieve a more economical production. The electromagnetic stirrer accelerates the melting rate of the charge, reduces the metal loss and improves the consistency of ingot quality. The Ingot Business Unit of ALCOA-KOFEM operates seven melting furnaces. Each furnace is equipped with a POTOK type MHD induction stirrer in order to achieve a more profitable melting operation. Magnetohydrodynamic stirrers were installed between 1988 and 1990 on melting furnaces ranging in capacity from 25 to 60 tons ofmore » molten metal.« less

Inductive displacement sensors with a notch filter for an active magnetic bearing system.

PubMed

Chen, Seng-Chi; Le, Dinh-Kha; Nguyen, Van-Sum

2014-07-15

Active magnetic bearing (AMB) systems support rotating shafts without any physical contact, using electromagnetic forces. Each radial AMB uses two pairs of electromagnets at opposite sides of the rotor. This allows the rotor to float in the air gap, and the machine to operate without frictional losses. In active magnetic suspension, displacement sensors are necessary to detect the radial and axial movement of the suspended object. In a high-speed rotating machine equipped with an AMB, the rotor bending modes may be limited to the operating range. The natural frequencies of the rotor can cause instability. Thus, notch filters are a useful circuit for stabilizing the system. In addition, commercial displacement sensors are sometimes not suitable for AMB design, and cannot filter the noise caused by the natural frequencies of rotor. Hence, implementing displacement sensors based on the AMB structure is necessary to eliminate noises caused by natural frequency disturbances. The displacement sensor must be highly sensitive in the desired working range, and also exhibit a low interference noise, high stability, and low cost. In this study, we used the differential inductive sensor head and lock-in amplifier for synchronous demodulation. In addition, an active low-pass filter and a notch filter were used to eliminate disturbances, which caused by natural frequencies. As a consequence, the inductive displacement sensor achieved satisfactory linearity, high sensitivity, and disturbance elimination. This sensor can be easily produced for AMB applications. A prototype of these displacement sensors was built and tested.

Molten metal feed system controlled with a traveling magnetic field

DOEpatents

Praeg, Walter F.

1991-01-01

A continuous metal casting system in which the feed of molten metal is controlled by means of a linear induction motor capable of producing a magnetic traveling wave in a duct that connects a reservoir of molten metal to a caster. The linear induction motor produces a traveling magnetic wave in the duct in opposition to the pressure exerted by the head of molten metal in the reservoir so that p.sub.c =p.sub.g -p.sub.m where p.sub.c is the desired pressure in the caster, p.sub.g is the gravitational pressure in the duct exerted by the force of the head of molten metal in the reservoir, and p.sub.m is the electromagnetic pressure exerted by the force of the magnetic field traveling wave produced by the linear induction motor. The invention also includes feedback loops to the linear induction motor to control the casting pressure in response to measured characteristics of the metal being cast.

Design of a Low-Energy FARAD Thruster

NASA Technical Reports Server (NTRS)

Polzin, K. A.; Rose, M. F.; Miller, R.; Best, S.; Owens, T.; Dankanich, J.

2007-01-01

The design of an electrodeless thruster that relies on a pulsed, rf-assisted discharge and electromagnetic acceleration using an inductive coil is presented. The thruster design is optimized using known performance,scaling parameters, and experimentally-determined design rules, with design targets for discharge energy, plasma exhaust velocity; and thrust efficiency of 100 J/pulse, 25 km/s, and 50%, respectively. Propellant is injected using a high-speed gas valve and preionized by a pulsed-RF signal supplied by a vector inversion generator, allowing for current sheet formation at lower discharge voltages and energies relative to pulsed inductive accelerators that do not employ preionization. The acceleration coil is designed to possess an inductance of at least 700 nH while the target stray (non-coil) inductance in the circuit is 70 nH. A Bernardes and Merryman pulsed power train or a pulse compression power train provide current to the acceleration coil and solid-state components are used to switch both powertrains.

Neutron detection using the superconducting Nb-based current-biased kinetic inductance detector

NASA Astrophysics Data System (ADS)

Shishido, Hiroaki; Yamaguchi, Hiroyuki; Miki, Yuya; Miyajima, Shigeyuki; Oikawa, Kenichi; Harada, Masahide; Hidaka, Mutsuo; Oku, Takayuki; Arai, Masatoshi; Fujimaki, Akira; Ishida, Takekazu

2017-09-01

We demonstrate neutron detection using a solid-state 3He-free superconducting current-biased kinetic inductance detector (CB-KID), which consists of a superconducting Nb meander line and 10B neutron absorption layer. The CB-KID is based on the transient process of kinetic inductance of Cooper pairs induced by the nuclear reaction between 10B and neutrons. Therefore, the CB-KID can be operated in a wide superconducting region in the bias current-temperature diagram, as demonstrated in this paper. The transient change of the kinetic inductance induces the electromagnetic wave pulse under a DC bias current. The signal propagates along the meander line toward both sides with opposite polarity, where the signal polarity is dominated by the bias current direction. The full width at half maximum of the signals remains on the order of a few tens of ns, which confirms the high-speed operation of our detectors. We determine the neutron incident position within 1.3 mm accuracy in one dimension using the multichannel CB-KIDs.

Empirical Evaluation of Advanced Electromagnetic Induction Systems - Factors Affecting Classification Effectiveness in Challenging Geologic Environments

DTIC Science & Technology

2016-10-01

Figure 2-2). The array structure is fabricated from PVC and Garolite fiberglass. The array is normally deployed on a set of wheels, resulting in a sensor...Low branches were cleared to 8 feet above ground to reduce obstruction of the RTS prism; large logs and fallen timber were not removed. CH2M also

A Comparison of Electromagnetic Induction Mapping to Measurements of Maximum Effluent Flow Depth for Assessing Flow Paths in Vegetative Treatment Areas

USDA-ARS?s Scientific Manuscript database

Vegetative treatment systems (VTSs) are one type of control structure that has shown potential to control runoff from open feedlots. To achieve maximum performance, sheet-flow over the width of the vegetative treatment area (VTA) is required. Tools, such as maps of flow paths through the VTA, are ne...

Radiation and Electromagnetic Induction Data Fusion for Detection of Buried Radioactive Metal Waste - 12282

DOE Office of Scientific and Technical Information (OSTI.GOV)

Long, Zhiling; Wei, Wei; Turlapaty, Anish

2012-07-01

At the United States Army's test sites, fired penetrators made of Depleted Uranium (DU) have been buried under ground and become hazardous waste. Previously, we developed techniques for detecting buried radioactive targets. We also developed approaches for locating buried paramagnetic metal objects by utilizing the electromagnetic induction (EMI) sensor data. In this paper, we apply data fusion techniques to combine results from both the radiation detection and the EMI detection, so that we can further distinguish among DU penetrators, DU oxide, and non- DU metal debris. We develop a two-step fusion approach for the task, and test it with surveymore » data collected on simulation targets. In this work, we explored radiation and EMI data fusion for detecting DU, oxides, and non-DU metals. We developed a two-step fusion approach based on majority voting and a set of decision rules. With this approach, we fuse results from radiation detection based on the RX algorithm and EMI detection based on a 3-step analysis. Our fusion approach has been tested successfully with data collected on simulation targets. In the future, we will need to further verify the effectiveness of this fusion approach with field data. (authors)« less

Multiconfiguration electromagnetic induction survey for paleochannel internal structure imaging: a case study in the alluvial plain of the River Seine, France

NASA Astrophysics Data System (ADS)

Rejiba, Fayçal; Schamper, Cyril; Chevalier, Antoine; Deleplancque, Benoit; Hovhannissian, Gaghik; Thiesson, Julien; Weill, Pierre

2018-01-01

The La Bassée floodplain area is a large groundwater reservoir controlling most of the water exchanged between local aquifers and hydrographic networks within the Seine River basin (France). Preferential flows depend essentially on the heterogeneity of alluvial plain infilling, whose characteristics are strongly influenced by the presence of mud plugs (paleomeander clayey infilling). These mud plugs strongly contrast with the coarse sand material that composes most of the alluvial plain, and can create permeability barriers to groundwater flows. A detailed knowledge of the global and internal geometry of such paleomeanders can thus lead to a comprehensive understanding of the long-term hydrogeological processes of the alluvial plain. A geophysical survey based on the use of electromagnetic induction was performed on a wide paleomeander, situated close to the city of Nogent-sur-Seine in France. In the present study we assess the advantages of combining several spatial offsets, together with both vertical and horizontal dipole orientations (six apparent conductivities), thereby mapping not only the spatial distribution of the paleomeander derived from lidar data but also its vertical extent and internal variability.

In situ determination of the static inductance and resistance of a plasma focus capacitor bank.

PubMed

Saw, S H; Lee, S; Roy, F; Chong, P L; Vengadeswaran, V; Sidik, A S M; Leong, Y W; Singh, A

2010-05-01

The static (unloaded) electrical parameters of a capacitor bank are of utmost importance for the purpose of modeling the system as a whole when the capacitor bank is discharged into its dynamic electromagnetic load. Using a physical short circuit across the electromagnetic load is usually technically difficult and is unnecessary. The discharge can be operated at the highest pressure permissible in order to minimize current sheet motion, thus simulating zero dynamic load, to enable bank parameters, static inductance L(0), and resistance r(0) to be obtained using lightly damped sinusoid equations given the bank capacitance C(0). However, for a plasma focus, even at the highest permissible pressure it is found that there is significant residual motion, so that the assumption of a zero dynamic load introduces unacceptable errors into the determination of the circuit parameters. To overcome this problem, the Lee model code is used to fit the computed current trace to the measured current waveform. Hence the dynamics is incorporated into the solution and the capacitor bank parameters are computed using the Lee model code, and more accurate static bank parameters are obtained.

In situ determination of the static inductance and resistance of a plasma focus capacitor bank

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saw, S. H.; Institute for Plasma Focus Studies, 32 Oakpark Drive, Chadstone, Victoria 3148; Lee, S.

2010-05-15

The static (unloaded) electrical parameters of a capacitor bank are of utmost importance for the purpose of modeling the system as a whole when the capacitor bank is discharged into its dynamic electromagnetic load. Using a physical short circuit across the electromagnetic load is usually technically difficult and is unnecessary. The discharge can be operated at the highest pressure permissible in order to minimize current sheet motion, thus simulating zero dynamic load, to enable bank parameters, static inductance L{sub 0}, and resistance r{sub 0} to be obtained using lightly damped sinusoid equations given the bank capacitance C{sub 0}. However, formore » a plasma focus, even at the highest permissible pressure it is found that there is significant residual motion, so that the assumption of a zero dynamic load introduces unacceptable errors into the determination of the circuit parameters. To overcome this problem, the Lee model code is used to fit the computed current trace to the measured current waveform. Hence the dynamics is incorporated into the solution and the capacitor bank parameters are computed using the Lee model code, and more accurate static bank parameters are obtained.« less

Design Considerations and Experimental Verification of a Rail Brake Armature Based on Linear Induction Motor Technology

NASA Astrophysics Data System (ADS)

Sakamoto, Yasuaki; Kashiwagi, Takayuki; Hasegawa, Hitoshi; Sasakawa, Takashi; Fujii, Nobuo

This paper describes the design considerations and experimental verification of an LIM rail brake armature. In order to generate power and maximize the braking force density despite the limited area between the armature and the rail and the limited space available for installation, we studied a design method that is suitable for designing an LIM rail brake armature; we considered adoption of a ring winding structure. To examine the validity of the proposed design method, we developed a prototype ring winding armature for the rail brakes and examined its electromagnetic characteristics in a dynamic test system with roller rigs. By repeating various tests, we confirmed that unnecessary magnetic field components, which were expected to be present under high speed running condition or when a ring winding armature was used, were not present. Further, the necessary magnetic field component and braking force attained the desired values. These studies have helped us to develop a basic design method that is suitable for designing the LIM rail brake armatures.

Universal 'imaginary closed circuit method' and formula for determination of direction of induced emf/current

NASA Astrophysics Data System (ADS)

Balaram Atram, Dattatraya

2011-01-01

Fleming's right-hand rule and the right-flat-hand rule are generally applied for determining the direction of flow of induced emf/current in straight conductors. The right-hand-fingers rule is applied for coils only. The right-hand-thumb rule can be applied for either straight conductors or coils. Different rules have to be applied for different situations. Also, a formula for determining the direction of induced emf/current does not exist on the basis of these rules. In this article, based on Faraday's law of electromagnetic induction and Lenz's law, an 'imaginary closed circuit method' and a formula for determination of direction of induced emf/current has been proposed. The method is universal in the sense that it is applicable for conductors of any shape, for any kind of relative motion of the conductor with respect to the magnetic flux, and moreover it is applicable for the case of varying magnetic flux.

Co-Design Method and Wafer-Level Packaging Technique of Thin-Film Flexible Antenna and Silicon CMOS Rectifier Chips for Wireless-Powered Neural Interface Systems.

PubMed

Okabe, Kenji; Jeewan, Horagodage Prabhath; Yamagiwa, Shota; Kawano, Takeshi; Ishida, Makoto; Akita, Ippei

2015-12-16

In this paper, a co-design method and a wafer-level packaging technique of a flexible antenna and a CMOS rectifier chip for use in a small-sized implantable system on the brain surface are proposed. The proposed co-design method optimizes the system architecture, and can help avoid the use of external matching components, resulting in the realization of a small-size system. In addition, the technique employed to assemble a silicon large-scale integration (LSI) chip on the very thin parylene film (5 μm) enables the integration of the rectifier circuits and the flexible antenna (rectenna). In the demonstration of wireless power transmission (WPT), the fabricated flexible rectenna achieved a maximum efficiency of 0.497% with a distance of 3 cm between antennas. In addition, WPT with radio waves allows a misalignment of 185% against antenna size, implying that the misalignment has a less effect on the WPT characteristics compared with electromagnetic induction.

Co-Design Method and Wafer-Level Packaging Technique of Thin-Film Flexible Antenna and Silicon CMOS Rectifier Chips for Wireless-Powered Neural Interface Systems

PubMed Central

Okabe, Kenji; Jeewan, Horagodage Prabhath; Yamagiwa, Shota; Kawano, Takeshi; Ishida, Makoto; Akita, Ippei

2015-01-01

In this paper, a co-design method and a wafer-level packaging technique of a flexible antenna and a CMOS rectifier chip for use in a small-sized implantable system on the brain surface are proposed. The proposed co-design method optimizes the system architecture, and can help avoid the use of external matching components, resulting in the realization of a small-size system. In addition, the technique employed to assemble a silicon large-scale integration (LSI) chip on the very thin parylene film (5 μm) enables the integration of the rectifier circuits and the flexible antenna (rectenna). In the demonstration of wireless power transmission (WPT), the fabricated flexible rectenna achieved a maximum efficiency of 0.497% with a distance of 3 cm between antennas. In addition, WPT with radio waves allows a misalignment of 185% against antenna size, implying that the misalignment has a less effect on the WPT characteristics compared with electromagnetic induction. PMID:26694407

A software solution to dynamically reduce metallic distortions of electromagnetic tracking systems for image-guided surgery.

PubMed

Li, Mengfei; Hansen, Christian; Rose, Georg

2017-09-01

Electromagnetic tracking systems (EMTS) have achieved a high level of acceptance in clinical settings, e.g., to support tracking of medical instruments in image-guided interventions. However, tracking errors caused by movable metallic medical instruments and electronic devices are a critical problem which prevents the wider application of EMTS for clinical applications. We plan to introduce a method to dynamically reduce tracking errors caused by metallic objects in proximity to the magnetic sensor coil of the EMTS. We propose a method using ramp waveform excitation based on modeling the conductive distorter as a resistance-inductance circuit. Additionally, a fast data acquisition method is presented to speed up the refresh rate. With the current approach, the sensor's positioning mean error is estimated to be 3.4, 1.3 and 0.7 mm, corresponding to a distance between the sensor and center of the transmitter coils' array of up to 200, 150 and 100 mm, respectively. The sensor pose error caused by different medical instruments placed in proximity was reduced by the proposed method to a level lower than 0.5 mm in position and [Formula: see text] in orientation. By applying the newly developed fast data acquisition method, we achieved a system refresh rate up to approximately 12.7 frames per second. Our software-based approach can be integrated into existing medical EMTS seamlessly with no change in hardware. It improves the tracking accuracy of clinical EMTS when there is a metallic object placed near the sensor coil and has the potential to improve the safety and outcome of image-guided interventions.

[Electromagnetic fields of mobile telephone systems--thresholds, effects and risks for cochlear implant patients and healthy people].

PubMed

Bischof, F; Langer, J; Begall, K

2008-11-01

Every day life is detectably affected by manifold natural sources of electromagnetic fields (EMF), e. g. infrared radiation, light and the terrestrial magnetic field. However, there is still uncertainty about the consequences or hazards of artificial EMF, which emerge from mobile phone or wireless network (wireless local area network [WLAN]) services, for instance. Following recommendations of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) the German Commission on Radiation Protection (SSK) defined corresponding thresholds for high frequency electromagnetic fields (HF-EMF) in 2003. By observing those thresholds HF-EMF is thought to be innocent so far. However, there is still controversial discussion about induction of cancer or neurovegetative symptoms due to inconsistent study results. Patients with cochlea implants are of particular interest within the speciality of otorhinolaryngology due to specific hazards, which arise during mobile telephone use from the distance between brain and inductive metal implants (electrode) on the one hand and the electronic system of the cochlear implant and the source of HF-EMF on the other hand. Besides many studies about the impact of HF-EMF on common welfare, there are only very few surveys (n = 6) covering the effects on patients with cochlear implants. The purpose of this paper is to overview sources, thresholds and subsequently harmful or harmless effects of HFEMF. Due to the current state of knowledge about the impact of mobile phone use on health, we assume, that HF-EMF are harmless both for healthy people and patients with cochlea implants, provided that legal thresholds are observed.

Near Surface Investigation of Agricultural Soils using a Multi-Frequency Electromagnetic Sensor

NASA Astrophysics Data System (ADS)

Sadatcharam, K.; Unc, A.; Krishnapillai, M.; Cheema, M.; Galagedara, L.

2017-12-01

Electromagnetic induction (EMI) sensors have been used as precision agricultural tools over decades. They are being used to measure spatiotemporal variability of soil properties and soil stratification in the sense of apparent electrical conductivity (ECa). We mapped the ECa variability by horizontal coplanar (HCP) and by vertical coplanar (VCP) orientation of a multi-frequency EMI sensor and identified its interrelation with physical properties of soil. A broadband, multi-frequency handheld EMI sensor (GEM-2) was used on a loamy sand soil cultivated with silage-corn in western Newfoundland, Canada. Log and line spaced, three frequency ranges (weak, low, and high), based on the factory calibration were tested using HCP and VCP orientation to produce spatiotemporal data of ECa. In parallel, we acquired data on soil moisture content, texture and bulk density. We then assessed the statistical significance of the relationship between ECa and soil physical properties. The test site had three areas of distinct soil properties corresponding to the elevation, in particular. The same spatial variability was also identified by ECa mapping at different frequencies and the two modes of coil orientations. Data analysis suggested that the high range frequency (38 kHz (log-spaced) and 49 kHz (line-spaced)) for both HCP and VCP orientations produced accurate ECa maps, better than the weak and low range frequencies tested. Furthermore, results revealed that the combined effects of soil texture, moisture content and bulk density affect ECameasurements as obtained by both frequencies and two coil orientations. Keywords: Apparent electrical conductivity, Electromagnetic induction, Horizontal coplanar, Soil properties, Vertical coplanar

Broadband EIT borehole measurements with high phase accuracy using numerical corrections of electromagnetic coupling effects

NASA Astrophysics Data System (ADS)

Zhao, Y.; Zimmermann, E.; Huisman, J. A.; Treichel, A.; Wolters, B.; van Waasen, S.; Kemna, A.

2013-08-01

Electrical impedance tomography (EIT) is gaining importance in the field of geophysics and there is increasing interest for accurate borehole EIT measurements in a broad frequency range (mHz to kHz) in order to study subsurface properties. To characterize weakly polarizable soils and sediments with EIT, high phase accuracy is required. Typically, long electrode cables are used for borehole measurements. However, this may lead to undesired electromagnetic coupling effects associated with the inductive coupling between the double wire pairs for current injection and potential measurement and the capacitive coupling between the electrically conductive shield of the cable and the electrically conductive environment surrounding the electrode cables. Depending on the electrical properties of the subsurface and the measured transfer impedances, both coupling effects can cause large phase errors that have typically limited the frequency bandwidth of field EIT measurements to the mHz to Hz range. The aim of this paper is to develop numerical corrections for these phase errors. To this end, the inductive coupling effect was modeled using electronic circuit models, and the capacitive coupling effect was modeled by integrating discrete capacitances in the electrical forward model describing the EIT measurement process. The correction methods were successfully verified with measurements under controlled conditions in a water-filled rain barrel, where a high phase accuracy of 0.8 mrad in the frequency range up to 10 kHz was achieved. The corrections were also applied to field EIT measurements made using a 25 m long EIT borehole chain with eight electrodes and an electrode separation of 1 m. The results of a 1D inversion of these measurements showed that the correction methods increased the measurement accuracy considerably. It was concluded that the proposed correction methods enlarge the bandwidth of the field EIT measurement system, and that accurate EIT measurements can now be made in the mHz to kHz frequency range. This increased accuracy in the kHz range will allow a more accurate field characterization of the complex electrical conductivity of soils and sediments, which may lead to the improved estimation of saturated hydraulic conductivity from electrical properties. Although the correction methods have been developed for a custom-made EIT system, they also have potential to improve the phase accuracy of EIT measurements made with commercial systems relying on multicore cables.

Effect of extremely low frequency electromagnetic field on brain histopathology of Caspian Sea Cyprinus carpio.

PubMed

Samiee, Farzaneh; Samiee, Keivandokht

2017-01-01

There is limited research on the effect of electromagnetic field on aquatic organisms, especially freshwater fish species. This study was conducted to evaluate the effect of extremely low frequency electromagnetic field (ELF-EMF) (50 Hz) exposure on brain histopathology of Cyprinus carpio, one of the important species of Caspian Sea with significant economic value. A total of 200 healthy fish were used in this study. They were classified randomly in two groups: sham-exposed group and experimental group, which were exposed to five different magnetic field intensities (0.1, 1, 3, 5, and 7 mT) at two different exposure times (0.5 and 1 h). Histologic results indicate that exposure of C. carpio to artificial ELF-EMF caused severe histopathological changes in the brain at field intensities ≥3 mT leading to brain necrosis. Field intensity and duration of exposure were key parameters in induction of lesion in the brain. Further studies are needed to elucidate exact mechanism of EMF exposure on the brain.

Current distribution measurements inside an electromagnetic plasma gun operated in a gas-puff mode.

PubMed

Poehlmann, Flavio R; Cappelli, Mark A; Rieker, Gregory B

2010-12-01

Measurements are presented of the time-dependent current distribution inside a coaxial electromagnetic plasma gun. The measurements are carried out using an array of six axially distributed dual-Rogowski coils in a balanced circuit configuration. The radial current distributions indicate that operation in the gas-puff mode, i.e., the mode in which the electrode voltage is applied before injection of the gas, results in a stationary ionization front consistent with the presence of a plasma deflagration. The effects of varying the bank capacitance, transmission line inductance, and applied electrode voltage were studied over the range from 14 to 112 μF, 50 to 200 nH, and 1 to 3 kV, respectively.

Current distribution measurements inside an electromagnetic plasma gun operated in a gas-puff mode

PubMed Central

Poehlmann, Flavio R.; Cappelli, Mark A.; Rieker, Gregory B.

2010-01-01

Measurements are presented of the time-dependent current distribution inside a coaxial electromagnetic plasma gun. The measurements are carried out using an array of six axially distributed dual-Rogowski coils in a balanced circuit configuration. The radial current distributions indicate that operation in the gas-puff mode, i.e., the mode in which the electrode voltage is applied before injection of the gas, results in a stationary ionization front consistent with the presence of a plasma deflagration. The effects of varying the bank capacitance, transmission line inductance, and applied electrode voltage were studied over the range from 14 to 112 μF, 50 to 200 nH, and 1 to 3 kV, respectively. PMID:21267082

SURFACE GEOPHYSICAL EXPLORATION OF B & BX & BY TANK FARMS AT THE HANFORD SITE RESULTS OF BACKGROUND CHARACTERIZATION WITH MAGNETICS AND ELECTROMAGNETICS

DOE Office of Scientific and Technical Information (OSTI.GOV)

MYERS DA

This report documents the results of preliminary surface geophysical exploration activities performed between October and December 2006 at the B, BX, and BY tank farms (B Complex). The B Complex is located in the 200 East Area of the U. S. Department of Energy's Hanford Site in Washington State. The objective of the preliminary investigation was to collect background characterization information with magnetic gradiometry and electromagnetic induction to understand the spatial distribution of metallic objects that could potentially interfere with the results from high resolution resistivity survey. Results of the background characterization show there are several areas located around themore » site with large metallic subsurface debris or metallic infrastructure.« less

Electromagnetic propulsion for spacecraft

NASA Technical Reports Server (NTRS)

Myers, Roger M.

1993-01-01

Three electromagnetic propulsion technologies, solid propellant pulsed plasma thrusters (PPT), magnetoplasmadynamic (MPD) thrusters, and pulsed inductive thrusters (PIT) have been developed for application to auxiliary and primary spacecraft propulsion. Both the PPT and MPD thrusters have been flown in space, though only PPTs have been used on operational satellites. The performance of operational PPTs is quite poor, providing only about 8 percent efficiency at about 1000 sec specific impulse. Laboratory PPTs yielding 34 percent efficiency at 5170 sec specific impulse have been demonstrated. Laboratory MPD thrusters have been demonstrated with up to 70 percent efficiency and 7000 sec specific impulse. Recent PIT performance measurements using ammonia and hydrazine propellants are extremely encouraging, reaching 50 percent efficiency for specific impulses between 4000 and 8000 sec.

Conductive Fabric-Based Stretchable Hybridized Nanogenerator for Scavenging Biomechanical Energy.

PubMed

Zhang, Kewei; Wang, Zhong Lin; Yang, Ya

2016-04-26

We demonstrate a stretchable hybridized nanogenerator based on a highly conductive fabric of glass fibers/silver nanowires/polydimethylsiloxane. Including a triboelectric nanogenerator and an electromagnetic generator, the hybridized nanogenerator can deliver output voltage/current signals from stretchable movements by both triboelectrification and electromagnetic induction, maximizing the efficiency of energy scavenging from one motion. Compared to the individual energy-harvesting units, the hybridized nanogenerator has a better charging performance, where a 47 μF capacitor can be charged to 2.8 V in only 16 s. The hybridized nanogenerator can be integrated with a bus grip for scavenging wasted biomechanical energy from human body movements to solve the power source issue of some electric devices in the pure electric bus.