WorldWideScience

Sample records for electrically small magnetic

  1. Minimum Q Electrically Small Spherical Magnetic Dipole Antenna - Practice

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.; Breinbjerg, Olav

    2009-01-01

    Practical aspects of applying a magnetic core to approach the Chu lower bound for the radiation Q factor of an electrically small magnetic dipole antenna are considered. It is shown that although a magnetic core does reduce the Q factor, its effect is not as strong as predicted by Wheeler...

  2. Low-Q Electrically Small Spherical Magnetic Dipole Antennas

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.

    2010-01-01

    Three novel electrically small antenna configurations radiating a TE10 spherical mode corresponding to a magnetic dipole are presented and investigated: multiarm spherical helix (MSH) antenna, spherical split ring resonator (S-SRR) antenna, and spherical split ring (SSR) antenna. All three antennas...... are self-resonant, with the input resistance tuned to 50 ohms by an excitation curved dipole/monopole. A prototype of the SSR antenna has been fabricated and measured, yielding results that are consistent with the numerical simulations. Radiation quality factors (Q) of these electrically small antennas (in...

  3. Electrically Small Magnetic Dipole Antennas with Magnetic Core

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.; Breinbjerg, Olav

    2010-01-01

    This work extends the theory of a spherical magnetic dipole antenna with magnetic core by numerical results for practical antenna configurations that excite higher-order modes besides the main TE10 spherical mode. The multiarm spherical helix (MSH) and the spherical split ring (SSR) antennas...

  4. Minimum Q Electrically Small Spherical Magnetic Dipole Antenna - Theory

    DEFF Research Database (Denmark)

    Breinbjerg, Olav; Kim, Oleksiy S.

    2009-01-01

    The stored energies, radiated power, and quality factor of a magnetic-dipole antenna, consisting of a spherical electrical surface current density enclosing a magnetic core, is obtained through direct spatial integration of the internally and externally radiated field expressed in terms...... of spherical vector waves. The obtained quality factor agrees with that of Wheeler and Thal for vanishing free-space electric radius but holds also for larger radii and facilitates the optimal choice of permeability in the presence of the resonances....

  5. Lower Bound for the Radiation $Q$ of Electrically Small Magnetic Dipole Antennas With Solid Magnetodielectric Core

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.; Breinbjerg, Olav

    2011-01-01

    A new lower bound for the radiation $Q$ of electrically small spherical magnetic dipole antennas with solid magnetodielectric core is derived in closed form using the exact theory. The new bound approaches the Chu lower bound from above as the antenna electrical size decreases. For $ka, the new...... bound is lower than the bounds for spherical magnetic as well as electric dipole antennas composed of impressed electric currents in free space....

  6. Quality factor of an electrically small magnetic dipole antenna with magneto-dielectric core

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.; Breinbjerg, Olav

    2010-01-01

    In this work, we investigate the radiation Q of electrically small magnetic dipole antennas with magneto-dielectric core versus the antenna electrical size, permittivity and permeability of the core. The investigation is based on the exact theory for a spherical magnetic dipole antenna...

  7. Non-foster impedance matching sensitivity of electrically small electric and magnetic spherical dipole antennas

    DEFF Research Database (Denmark)

    Yoon, Ick-Jae; Christensen, S.; Zhurbenko, Vitaliy

    2016-01-01

    The impedance bandwidth (BW) improvement property of a self-resonant folded spherical helix electric dipole and a spherical split ring (SSR) magnetic dipole is compared when a negative reactance element is loaded on the parasitic resonator of the antennas. They have the same electrical size of ka...

  8. Electrically Small Magnetic Dipole Antennas With Quality Factors Approaching the Chu Lower Bound

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.; Breinbjerg, Olav; Yaghjian, Arthur D.

    2010-01-01

    We investigate the quality factor Q for electrically small current distributions and practical antenna designs radiating the TE10 magnetic dipole field. The current distributions and the antenna designs employ electric currents on a spherical surface enclosing a magneto-dielectric material...... numerically. It is found that for a given antenna size and permittivity there is an optimum permeability that ensures the lowest possible Q, and this optimum permeability is inversely proportional to the square of the antenna electrical radius. When the relative permittivity is equal to 1, the optimum...... permeability yields the quality factor Q that constitutes the lower bound for a magnetic dipole antenna with a magneto-dielectric core. Furthermore, the smaller the antenna the closer its quality factor Q can approach the Chu lower bound. Simulated results for the TE10-mode multiarm spherical helix antenna...

  9. MMS Multipoint Electric Field Observations of Small-Scale Magnetic Holes

    Science.gov (United States)

    Goodrich, Katherine A.; Ergun, Robert E.; Wilder, Frederick; Burch, James; Torbert, Roy; Khotyaintsev, Yuri; Lindqvist, Per-Arne; Russell, Christopher; Strangeway, Robert; Magnus, Werner

    2016-01-01

    Small-scale magnetic holes (MHs), local depletions in magnetic field strength, have been observed multiple times in the Earths magnetosphere in the bursty bulk flow (BBF) braking region. This particular subset of MHs has observed scale sizes perpendicular to the background magnetic field (B) less than the ambient ion Larmor radius (p(sib i)). Previous observations by Time History of Events and Macroscale Interactions during Substorms (THEMIS) indicate that this subset of MHs can be supported by a current driven by the E x B drift of electrons. Ions do not participate in the E x B drift due to the small-scale size of the electric field. While in the BBF braking region, during its commissioning phase, the Magnetospheric Multiscale (MMS) spacecraft observed a small-scale MH. The electric field observations taken during this event suggest the presence of electron currents perpendicular to the magnetic field. These observations also suggest that these currents can evolve to smaller spatial scales.

  10. Minimum Q Electrically Small Antennas

    DEFF Research Database (Denmark)

    Kim, O. S.

    2012-01-01

    Theoretically, the minimum radiation quality factor Q of an isolated resonance can be achieved in a spherical electrically small antenna by combining TM1m and TE1m spherical modes, provided that the stored energy in the antenna spherical volume is totally suppressed. Using closed-form expressions...... for a multiarm spherical helix antenna confirm the theoretical predictions. For example, a 4-arm spherical helix antenna with a magnetic-coated perfectly electrically conducting core (ka=0.254) exhibits the Q of 0.66 times the Chu lower bound, or 1.25 times the minimum Q....

  11. Measured surface magnetic field attenuation of shielded windows and wire mesh over an electrically small enclosure

    International Nuclear Information System (INIS)

    Hoeft, L.O.; Hofstra, J.S.; Karaskiewicz, R.J.; Wiser, G.

    1984-01-01

    The surface magnetic field attenuation of five types of shielded transparency (window) material was measured over the frequency range 10 kHz to 100 MHz by installing them on an .61 m x .61 m x .2 m enclosure, placing the enclosure on the wall of a TEM cell and measuring the surface and interior magnetic fields using a computer-controlled network analyzer system. The samples included two thicknesses of conductive grids on acrylic, hardware, cloth with 1/8 and 1/4-inch mesh, and a fine mesh laminated optical display window. These measurements are indicative of an enclosure with aperture coupling; namely, they become frequency-independent at high frequencies. Coarse mesh samples (1/8-1/4-inch mesh) were able to provide 50 to 60 dB of magnetic field reduction at tens of MHz, whereas the finer mesh did slightly better. This behavior is consistent with magnetic polarizability theory. Material thickness did not have an appreciable effect for frequencies above a MHz

  12. Electricity and magnetism

    CERN Document Server

    Robertson, William C

    2005-01-01

    Shocked by static? Mixed up about magnets? Curious about currents? This book will help you get beyond memorizing electricity-related formulas, rules, and procedures so you can understand the topic at a deep level deep enough to teach it with confidence and comfort. By covering the basics of static electricity, current electricity, and magnetism, the book develops a scientific model showing that electricity and magnetism are really the same phenomenon in different forms. A bonus feature: access to interactive software that you can download from the NSTA Web site. The software will help you investigate electrical circuits from simple to complex without having to buy a lot of expensive materials (or risking electrocution!). Electricity and Magnetism is the fifth title in the award-winning NSTA Press Stop Faking It! Series. As author Bill Robertson writes, The book you have in your hands is not a textbook. It is, however, designed to help you get science at a level you never thought possible, and also to bring yo...

  13. Novel Electrically Small Spherical Electric Dipole Antenna

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.

    2010-01-01

    This paper introduces a novel electrically small spherical meander antenna. Horizontal sections of the meander are composed of wire loops, radii of which are chosen so that the whole structure is conformal to a sphere of radius a. To form the meander the loops are connected by wires at a meridian...

  14. Magnet management in electric machines

    Science.gov (United States)

    Reddy, Patel Bhageerath; El-Refaie, Ayman Mohamed Fawzi; Huh, Kum Kang

    2017-03-21

    A magnet management method of controlling a ferrite-type permanent magnet electrical machine includes receiving and/or estimating the temperature permanent magnets; determining if that temperature is below a predetermined temperature; and if so, then: selectively heating the magnets in order to prevent demagnetization and/or derating the machine. A similar method provides for controlling magnetization level by analyzing flux or magnetization level. Controllers that employ various methods are disclosed. The present invention has been described in terms of specific embodiment(s), and it is recognized that equivalents, alternatives, and modifications, aside from those expressly stated, are possible and within the scope of the appending claims.

  15. Electrically Controllable Magnetism in Twisted Bilayer Graphene.

    Science.gov (United States)

    Gonzalez-Arraga, Luis A; Lado, J L; Guinea, Francisco; San-Jose, Pablo

    2017-09-08

    Twisted graphene bilayers develop highly localized states around AA-stacked regions for small twist angles. We show that interaction effects may induce either an antiferromagnetic or a ferromagnetic (FM) polarization of said regions, depending on the electrical bias between layers. Remarkably, FM-polarized AA regions under bias develop spiral magnetic ordering, with a relative 120° misalignment between neighboring regions due to a frustrated antiferromagnetic exchange. This remarkable spiral magnetism emerges naturally without the need of spin-orbit coupling, and competes with the more conventional lattice-antiferromagnetic instability, which interestingly develops at smaller bias under weaker interactions than in monolayer graphene, due to Fermi velocity suppression. This rich and electrically controllable magnetism could turn twisted bilayer graphene into an ideal system to study frustrated magnetism in two dimensions.

  16. Minimum Q circularly polarized electrically small spherical antennas

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.

    2011-01-01

    The radiation problem for the TM10- and TE10-mode electric current densities on the surface of a spherical magnetic-coated PEC core is solved analytically. The combination of the electric and magnetic dipole modes reduces the radiation Q of the antenna. Moreover, with an appropriately designed...... magnetic-coated PEC core the stored energies of these modes balance each other making the antenna self-resonant and at the same time ensuring a perfect circularly polarized radiation. Numerical results for a practical dual-mode electrically small antenna confirm the theoretical predictions. A 4-arm...

  17. Electrical measurements during magnet construction

    International Nuclear Information System (INIS)

    Sintchak, G.; Ganetis, G.; Cottingham, G.

    1989-01-01

    Throughout the construction phase of the cold mass for SSC magnets, electrical tests are made to determine that no faults in the coil structure have developed. These tests include ones designed to measure turn-to-turn voltage hold-off, hypot tests to ground, coil resistance, and instrumentation checks. These various tests will be described and the test parameters that are used will be covered. 4 figs

  18. Phonon-assisted transitions in crossed electric and magnetic fields

    International Nuclear Information System (INIS)

    Hassan, A.R.

    1980-05-01

    A theory of the effect of a crossed electric, E, and magnetic, H, fields in the indirect transitions in semiconductors is developed. A semi-classical treatment is adopted where the electric field is considered as a small perturbation. A numerical application to GaP gives the limiting values of E/H valid to this approach. (author)

  19. Classical theory of electric and magnetic fields

    CERN Document Server

    Good, Roland H

    1971-01-01

    Classical Theory of Electric and Magnetic Fields is a textbook on the principles of electricity and magnetism. This book discusses mathematical techniques, calculations, with examples of physical reasoning, that are generally applied in theoretical physics. This text reviews the classical theory of electric and magnetic fields, Maxwell's Equations, Lorentz Force, and Faraday's Law of Induction. The book also focuses on electrostatics and the general methods for solving electrostatic problems concerning images, inversion, complex variable, or separation of variables. The text also explains ma

  20. Electrical, Magnetic, and Optical Measurement Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Provides tools necessary for electrical, magnetic, and optical characterization of bulk and thin-film materials. This includes the ability to determine the...

  1. Small polaron hopping in magnetic semiconductors

    International Nuclear Information System (INIS)

    Emin, D.; Liu, N.L.H.

    1978-01-01

    In a number of magnetic insulators it has been hypothesized that the charge carriers form small polarons. The transfer of an electron between magnetic sites and how the magnetic nature of the material affects the rate which characterizes small-polaron hops between magnetic sites were studied. The basic transfer processes are addressed from a many-electron point in which the itinerant electron is treated as indistinguishable from those which contribute unpaired spins at the magnetic sites

  2. 3D Printing Electrically Small Spherical Antennas

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.

    2013-01-01

    3D printing is applied for rapid prototyping of an electrically small spherical wire antenna. The model is first printed in plastic and subsequently covered with several layers of conductive paint. Measured results are in good agreement with simulations.......3D printing is applied for rapid prototyping of an electrically small spherical wire antenna. The model is first printed in plastic and subsequently covered with several layers of conductive paint. Measured results are in good agreement with simulations....

  3. Magnetism and Electricity Activity "Attracts" Student Interest

    Science.gov (United States)

    Roman, Harry T.

    2010-01-01

    Electricity and magnetism are intimately linked, this relationship forming the basis of the modern electric utility system and the generation of bulk electrical energy. There is rich literature from which to teach students the basics, but nothing drives the point home like having them learn from firsthand experience--and that is what this…

  4. Structural peculiarities in magnetic small particles

    International Nuclear Information System (INIS)

    Haneda, K.; Morrish, A.H.

    1993-01-01

    Nanostructured magnetic materials, consisting of nanometer-sized crystallites, are currently a developing subject. Evidence has been accumulating that they possess properties that can differ substantially from those of bulk materials. This paper illustrates how Moessbauer spectroscopy can yield useful information on the structural peculiarities associated with these small particles. As illustrations, metallic iron and iron-oxide systems are considered in detail. The subjects discussed include: (1) Phase stabilities in small particles, (2) deformed or nonsymmetric atomic arrangements in small particles, and (3) peculiar magnetic structures or non-collinear spin arrangements in small magnetic oxide particles that are correlated with lower specific magnetizations as compared to the bulk values. (orig.)

  5. Behavior of small ferromagnetic particles in traveling magnetic field

    Science.gov (United States)

    Deych, V. G.; Terekhov, V. P.

    1985-03-01

    Forces and moments acting on a magnetizable body in a traveling magnetic field are calculated for a body with dimensions much smaller than the wavelength of the magnetic field. It is assumed that a particle of given linear dimension does not have a constant magnetic moment. The material of a particle is characterized by its magnetic permeability and electrical conductivity. The hypothesis that rotation plays a major role in the behavior of small particles is confirmed and the fact that a small particle rolls on a plane, without sliding, when the surface is perfectly rough, in the opposite direction from which the magnetic field travels is explained. Calculations are based on the magnetohydrodynamic equations for a quasi steady magnetic field, and the induced Foucault eddy currents are considered. The results are applicable to transport of ferrofluids and to such metallurgical devices as separators.

  6. Small and smart magnet design

    DEFF Research Database (Denmark)

    Frandsen, Cathrine; Beleggia, Marco; Brok, Erik

    2014-01-01

    Society faces an accumulated need to find ways to produce super strong magnets that can fulfill thegrowing demands for green technology products such as compact and efficient generators and motors. Next‐generation magnets could very likely be composite materials built bottom‐up from nanoparticles....... However, combining the nanoparticles into a compact magnetic material where all magnetic moments are aligned is an engineering challenge. We investigate ‐ with nanoparticle‐resolution – principles of assembly processes and particle arrangements that can generate optimal magnetic order in new materials...... (see e.g.Fig. 1). These studies are enabled by advanced transmission electron microscopy, magnetic modelling and new synthesis protocols. Examples of magnetic ordering and self‐organization will be given....

  7. Magnetic and Electrical Properties of Leachate

    Directory of Open Access Journals (Sweden)

    Kartika Kirana

    2011-11-01

    Full Text Available Heavy metals content as well as magnetic and electrical properties of leachate from Sarimukti, West Java were studied in an attempt to seek correlation between heavy metals content and magnetic/electrical properties. Such correlation is expected to open the way for the use of magnetic/electrical properties as proxy indicators for the concentration of heavy metals in the leachate. The number of leachate samples studied is 21; 15 were taken spatially at depth of 1 m while the remaining 6 samples were taken vertically at a particular point. Measurement results showed that the heavy metals content in the leachate has a smaller concentration, except for Fe. The correlation between magnetic susceptibility and heavy metals content was found to be not so significant. The best correlation coefficient between magnetic susceptibility with heavy metals in leachate was found in Zn. Correlation between electrical conductivity and heavy metal is also not so significant, except for Zn and Cd. The use of magnetic properties as proxy indicator for heavy metals content in leachate is plausible provided that the magnetic susceptibility exceeds certain threshold value. Correlation between magnetic susceptibility, electrical conductivity and heavy metal content would be good if each quantity has a large value.

  8. Magnetic Signature of Brushless Electric Motors

    National Research Council Canada - National Science Library

    Clarke, David

    2006-01-01

    Brushless electric motors are used in a number of underwater vehicles. When these underwater vehicles are used for mine clearance operations the magnetic signature of the brushless motors is important...

  9. Can (electric-magnetic) duality be gauged?

    International Nuclear Information System (INIS)

    Bunster, Claudio; Henneaux, Marc

    2011-01-01

    There exists a formulation of the Maxwell theory in terms of two vector potentials, one electric and one magnetic. The action is then manifestly invariant under electric-magnetic duality transformations, which are rotations in the two-dimensional internal space of the two potentials, and local. We ask the question: Can duality be gauged? The only known and battle-tested method of accomplishing the gauging is the Noether procedure. In its decanted form, it amounts to turning on the coupling by deforming the Abelian gauge group of the free theory, out of whose curvatures the action is built, into a non-Abelian group which becomes the gauge group of the resulting theory. In this article, we show that the method cannot be successfully implemented for electric-magnetic duality. We thus conclude that, unless a radically new idea is introduced, electric-magnetic duality cannot be gauged. The implication of this result for supergravity is briefly discussed.

  10. Mensuration of magnetic and electric characteristics

    International Nuclear Information System (INIS)

    Owen M, Eduardo; Sarria Navarro, Erika; Fula, Marco Antonio

    2000-01-01

    The paper presents the design of a virtual instrument (VI) that allows the quick and precise measure of the magnetic behavior (of the materials), under the magnetization cycle. Additionally, the (VI) will be in capacity of measuring the electric impedance of an element or electric circuit. The virtual instrument was elaborated in the tool of virtual instrumentation Lab View 4.0 of National Instruments

  11. Modified small angle magnetization rotation method in multilayer magnetic microwires

    International Nuclear Information System (INIS)

    Torrejon, J.; Badini, G.; Pirota, K.; Vazquez, M.

    2007-01-01

    The small angle magnetization rotation (SAMR) technique is a widely used method to quantify magnetostriction in elongated ultrasoft magnetic materials. In the present work, we introduce significant optimization of the method, particularly simplification of the required equipment, profiting of the very peculiar characteristics of a recently introduced family of multilayer magnetic microwires consisting of a soft magnetic core, insulating intermediate layer and a hard magnetic outer layer. The introduced modified SAMR method is used not only to determine the saturation magnetostriction constant of the soft magnetic nucleus but also the magnetoelastic and magnetostatic coupling. This new method has a great potential in multifunctional sensor applications

  12. Superconducting magnetic systems and electrical machines

    International Nuclear Information System (INIS)

    Glebov, I.A.

    1975-01-01

    The use of superconductors for magnets and electrical machines attracts close attention of designers and scientists. A description is given of an ongoing research program to create superconductive magnetic systems, commutator motors, homopolar machines, topological generators and turbogenerators with superconductive field windings. All the machines are tentative experimental models and serve as a basis for further developments

  13. Superconducting magnetic energy storage for electric utilities and fusion systems

    International Nuclear Information System (INIS)

    Rogers, J.D.; Boenig, H.J.; Hassenzahl, W.V.

    1978-01-01

    Superconducting inductors provide a compact and efficient means of storing electrical energy without an intermediate conversion process. Energy storage inductors are under development for load leveling and transmission line stabilization in electric utility systems and for driving magnetic confinement and plasma heating coils in fusion energy systems. Fluctuating electric power demands force the electric utility industry to have more installed generating capacity than the average load requires. Energy storage can increase the utilization of base-load fossil and nuclear power plants for electric utilities. The Los Alamos Scientific Laboratory and the University of Wisconsin are developing superconducting magnetic energy storage (SMES) systems, which will store and deliver electrical energy for load leveling, peak shaving, and the stabilization of electric utility networks. In the fusion area, inductive energy transfer and storage is being developed. Both 1-ms fast-discharge theta-pinch systems and 1-to-2-s slow energy transfer tokamak systems have been demonstrated. The major components and the method of operation of a SMES unit are described, and potential applications of different size SMES systems in electric power grids are presented. Results are given of a reference design for a 10-GWh unit for load leveling, of a 30-MJ coil proposed for system stabilization, and of tests with a small-scale, 100-kJ magnetic energy storage system. The results of the fusion energy storage and transfer tests are presented. The common technology base for the various storage systems is discussed

  14. 77 FR 26607 - Energy Conservation Program: Test Procedures for Electric Motors and Small Electric Motors

    Science.gov (United States)

    2012-05-04

    ... Conservation Program: Test Procedures for Electric Motors and Small Electric Motors; Final Rules #0;#0;Federal... Procedures for Electric Motors and Small Electric Motors AGENCY: Office of Energy Efficiency and Renewable... electric motors and small electric motors. That supplemental proposal, along with an earlier proposal from...

  15. Hofstadter spectrum in electric and magnetic fields

    International Nuclear Information System (INIS)

    Kunold, Alejandro; Torres, Manuel

    2005-01-01

    The problem of Bloch electrons in two dimensions subjected to magnetic and intense electric fields is investigated. Magnetic translations, electric evolution, and energy translation operators are used to specify the solutions of the Schroedinger equation. For rational values of the magnetic flux quanta per unit cell and commensurate orientations of the electric field relative to the original lattice, an extended superlattice can be defined and a complete set of mutually commuting space-time symmetry operators is obtained. Dynamics of the system is governed by a finite difference equation that exactly includes the effects of: an arbitrary periodic potential, an electric field orientated in a commensurable direction of the lattice, and coupling between Landau levels. A weak periodic potential broadens each Landau level in a series of minibands, separated by the corresponding minigaps. The addition of the electric field induces a series of avoided and exact crossing of the quasienergies, for sufficiently strong electric field the spectrum evolves into equally spaced discreet levels, in this 'magnetic Stark ladder' the energy separation is an integer multiple of hE/aB, with a the lattice parameter

  16. Magnetic nanoparticles studied by small angle X-ray scattering

    International Nuclear Information System (INIS)

    Oliveira, Cristiano Luis Pinto; Antonel, Soledad; Negri, Martin

    2011-01-01

    because they exhibit magnetic (ferromagnetic) and electrical properties in the same material. Then, the nickel nanoparticles could be used for the development of electroelastic materials. In this case, the electrical conductivity of the material can be strongly dependent on the applied magnetic field, for example the case of nickel metal nanoparticles dispersed in a polymer, resulting in an anisotropic material with combined piezomagnetic and piezoelectric properties. In order to investigate the structural characteristics of cobalt-iron oxides and nickel nanoparticles, powder samples of those magnetic materials were studied by Small-Angle X-Ray Scattering. As will be shown, from the analysis and modeling of the scattering data, structural information could be obtained, enabling a detailed description of the structural properties of the studied samples which could be directly correlated to the magnetic properties. (author)

  17. Magnetic nanoparticles studied by small angle X-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Cristiano Luis Pinto [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica. Grupo de Fluidos Complexos; Antonel, Soledad; Negri, Martin [Universidad de Buenos Aires (UBA) (Argentina). Facultad de Ciencias Exactas y Naturales. Dept. de Quimica Inorganica, Analitica y Quimica Fisica

    2011-07-01

    nanoparticles are very interesting because they exhibit magnetic (ferromagnetic) and electrical properties in the same material. Then, the nickel nanoparticles could be used for the development of electroelastic materials. In this case, the electrical conductivity of the material can be strongly dependent on the applied magnetic field, for example the case of nickel metal nanoparticles dispersed in a polymer, resulting in an anisotropic material with combined piezomagnetic and piezoelectric properties. In order to investigate the structural characteristics of cobalt-iron oxides and nickel nanoparticles, powder samples of those magnetic materials were studied by Small-Angle X-Ray Scattering. As will be shown, from the analysis and modeling of the scattering data, structural information could be obtained, enabling a detailed description of the structural properties of the studied samples which could be directly correlated to the magnetic properties. (author)

  18. Electric arc behaviour in dynamic magnetic fields

    International Nuclear Information System (INIS)

    Put'ko, V.F.

    2000-01-01

    The behaviour of an electric arc in different time-dependent (dynamic) magnetic fields was investigated. New possibilities were found for spatial and energy stabilisation of a discharge, for intensifying heat exchange, extending the electric arc and distributed control of electric arc plasma. Rotating, alternating and travelling magnetic fields were studied. It was found that under the effect of a relatively low frequency of variations of dynamic magnetic fields (f 1000 Hz) the arc stabilised at the axis of the discharge chamber, the pulsation level decreased and discharge stability increased. The borders between these two arc existence modes were formed by a certain critical field variation frequency the period of which was determined by the heat relaxation time of the discharge. (author)

  19. Electrically induced magnetic fields; a consistent approach

    Science.gov (United States)

    Batell, Brian; Ferstl, Andrew

    2003-09-01

    Electromagnetic radiation exists because changing magnetic fields induce changing electric fields and vice versa. This fact often appears inconsistent with the way some physics textbooks solve particular problems using Faraday's law. These types of problems often ask students to find the induced electric field given a current that does not vary linearly with time. A typical example involves a long solenoid carrying a sinusoidal current. This problem is usually solved as an example or assigned as a homework exercise. The solution offered by many textbooks uses the approximation that the induced, changing electric field produces a negligible magnetic field, which is only valid at low frequencies. If this approximation is not explicitly acknowledged, then the solution appears inconsistent with the description of electromagnetic radiation. In other cases, when the problem is solved without this approximation, the electric and magnetic fields are derived from the vector potential. We present a detailed calculation of the electric and magnetic fields inside and outside the long solenoid without using the vector potential. We then offer a comparison of our solution and a solution given in an introductory textbook.

  20. ELECTRIC AND MAGNETIC FIELDS ELECTRIC AND GASOLINE-POWERED VEHICLES.

    Science.gov (United States)

    Tell, Richard A; Kavet, Robert

    2016-12-01

    Measurements were conducted to investigate electric and magnetic fields (EMFs) from 120 Hz to 10 kHz and 1.2 to 100 kHz in 9 electric or hybrid vehicles and 4 gasoline vehicles, all while being driven. The range of fields in the electric vehicles enclosed the range observed in the gasoline vehicles. Mean magnetic fields ranged from nominally 0.6 to 3.5 µT for electric/hybrids depending on the measurement band compared with nominally 0.4 to 0.6 µT for gasoline vehicles. Mean values of electric fields ranged from nominally 2 to 3 V m -1 for electric/hybrid vehicles depending on the band, compared with 0.9 to 3 V m -1 for gasoline vehicles. In all cases, the fields were well within published exposure limits for the general population. The measurements were performed with Narda model EHP-50C/EHP-50D EMF analysers that revealed the presence of spurious signals in the EHP-50C unit, which were resolved with the EHP-50D model. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. Electric and Magnetic Dipole Moments

    CERN Document Server

    CERN. Geneva

    2005-01-01

    The stringent limit on the electric dipole moment of the neutron forced the issue on the strong CP-problem. The most elegant solution of which is the axion field proposed by Peccei and Quinn. The current limit on the QCD parameter theta coming from the limit on the neutron EDM is of order 10-10. I am going to describe the present status on the neutron EDM searches and further prospects on getting down to theta_qcd sensitivity of 10-13 with the new deuteron EDM in storage rings proposal. For completeness the current status and prospects of the muon g-2 experiment will also be given.

  2. 76 FR 647 - Energy Conservation Program: Test Procedures for Electric Motors and Small Electric Motors

    Science.gov (United States)

    2011-01-05

    ... Electric Motors and Small Electric Motors; Proposed Rule #0;#0;Federal Register / Vol. 76, No. 3... Motors and Small Electric Motors AGENCY: Office of Energy Efficiency and Renewable Energy, Department of... motors and small electric motors, clarify the scope of energy conservation standards for electric motors...

  3. Electric magnetic duality in string theory

    International Nuclear Information System (INIS)

    Sen, A.

    1992-07-01

    The electric-magnetic duality transformation in four dimensional heterotic string theory discussed by Shapere, Trivedi and Wilczek is shown to be an exact symmetry of the equations of motion of low energy effective field theory even after including the scalar and the vector fields, arising due to compactification, in the effective field theory. Using this duality transformation we construct rotating black hole solutions in the effective field theory carrying both electric and magnetic charges. The spectrum of extremal magnetically charged black holes turn out to be similar to that of electrically charged elementary string excitations lying on the leading Regge trajectory. We also discuss the possibility that the duality symmetry is an exact symmetry of the full string theory under which electrically charged elementary string excitations get exchanged with magnetically charged soliton like solutions. This proposal might be made concrete following the suggestion of Dabholkar et. al. that fundamental strings may be regarded as soliton like classical solutions in the effective field theory. (author). 20 refs

  4. Adopting small-scale production of electricity

    Energy Technology Data Exchange (ETDEWEB)

    Tengvard, Maria; Palm, Jenny (Linkoeping Univ., Dept. of Technology and Social Change, Linkoeping (Sweden)). e-mail: maria.tengvard@liu.se

    2009-07-01

    In Sweden in 2008, a 'new' concept for small-scale electricity production attracted massive media attention. This was mainly due to the efforts of Swedish company Egen El, which is marketing small-scale photovoltaics (PVs) and wind turbines to households, both homeowners and tenants. Their main selling point is simplicity: their products are so easy to install that everyone can do it. Autumn 2008 also saw IKEA announce that within three years it would market solar panels. How, then, do households perceive these products? Why would households choose to buy them? How do households think about producing their own electricity? Analysis of material based on in-depth interviews with members of 20 households reveals that environmental concerns supply the main motive for adopting PVs or micro wind power generation. In some cases, the adopting households have an extensively ecological lifestyle and such adoption represents a way to take action in the energy area. For some, this investment is symbolic: a way of displaying environmental consciousness or setting an example to others. For still others, the adoption is a protest against 'the system' with its large dominant actors or is a way to become self-sufficient. These microgeneration installations are rejected mainly on economic grounds; other motives are respect for neighbours and difficulties finding a place to install a wind turbine.

  5. Interaction of gravitational waves with magnetic and electric fields

    International Nuclear Information System (INIS)

    Barrabes, C.; Hogan, P. A.

    2010-01-01

    The existence of large-scale magnetic fields in the universe has led to the observation that if gravitational waves propagating in a cosmological environment encounter even a small magnetic field then electromagnetic radiation is produced. To study this phenomenon in more detail we take it out of the cosmological context and at the same time simplify the gravitational radiation to impulsive waves. Specifically, to illustrate our findings, we describe the following three physical situations: (1) a cylindrical impulsive gravitational wave propagating into a universe with a magnetic field, (2) an axially symmetric impulsive gravitational wave propagating into a universe with an electric field and (3) a 'spherical' impulsive gravitational wave propagating into a universe with a small magnetic field. In cases (1) and (3) electromagnetic radiation is produced behind the gravitational wave. In case (2) no electromagnetic radiation appears after the wave unless a current is established behind the wave breaking the Maxwell vacuum. In all three cases the presence of the magnetic or electric fields results in a modification of the amplitude of the incoming gravitational wave which is explicitly calculated using the Einstein-Maxwell vacuum field equations.

  6. The dynamic behavior of magnetic fluid adsorbed to small permanent magnet in alternating magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Sudo, Seiichi, E-mail: sudo@akita-pu.ac.j [Faculty of Systems Science and Technology, Akita Prefectural University, Ebinokuchi 84-4, Yurihonjo 015-0055 (Japan); Asano, Daisaku [Faculty of Systems Science and Technology, Akita Prefectural University, Ebinokuchi 84-4, Yurihonjo 015-0055 (Japan); Takana, Hidemasa; Nishiyama, Hideya [Institute of Fluid Science, Tohoku University, Katahira 2-1-1, Aobaku, Sendai 980-8577 (Japan)

    2011-05-15

    The dynamic behavior of a magnetic fluid adsorbed to a small NdFeB permanent magnet subjected to an alternating magnetic field was studied with a high speed video camera system. The directions of alternating magnetic field are parallel and opposite to that of the permanent magnet. It was found that the surface of magnetic fluid responds to the external alternating magnetic field in elongation and contraction with a lot of spikes. Generation of a capillary magnetic fluid jet was observed in the neighbourhood of a specific frequency of alternating field. The effect of gravitational force on surface phenomena of magnetic fluid adsorbed to the permanent magnet was revealed. - Research Highlights: Magnetic fluid of the system responds to alternating magnetic field with higher frequencies. Large-amplitude surface motions of magnetic fluid occur at the specific frequencies of the external field. Capillary jets of magnetic fluid are generated at the natural frequency of the system.

  7. Improving Students' Understanding of Electricity and Magnetism

    Science.gov (United States)

    Li, Jing

    2012-01-01

    Electricity and magnetism are important topics in physics. Research shows that students have many common difficulties in understanding concepts related to electricity and magnetism. However, research to improve students' understanding of electricity and magnetism is limited compared to introductory mechanics. This thesis explores issues…

  8. Magnetic bearing flywheels for electric storage

    Energy Technology Data Exchange (ETDEWEB)

    Poubeau, P C

    1981-01-01

    A magnetic bearing flywheel was designed. In order to have a simple, reliable system, magnetic suspension with a single servoloop for one degree of freedom of the rotor was used, four other degrees of freedom being controlled passively and the sixth one, corresponding to the rotation axis. The motor that transfers electric energy to the rotor is of the ironless brushless dc type with electronic commutation. It is operated alternatively for accelerating the wheel and then as a generator for delivering the stored energy. The use of high stress composite materials in the rotor greatly increases the operational limits of this equipment. Key characteristics of kinetic energy storage are mentioned along with a wide range of applications. Besides energy storage for satellites, these include power smoothing for solar and wind energy systems as well as backup power supplies, e.g., for electric vehicles.

  9. Electrical and magnetic fields of the power supply

    International Nuclear Information System (INIS)

    2017-01-01

    The availability of electrical energy in all areas of life is guaranteed by a widely ramified power grid. When electricity is transported, magnetic fields are created in addition to the electrical fields. In this brochure one will learn more about the causes and effects of electrical and magnetic fields as well as protection concepts and preventive measures. [de

  10. Electric polarization of magnetic textures: New horizons of micromagnetism

    International Nuclear Information System (INIS)

    Pyatakov, A.P.; Meshkov, G.A.; Zvezdin, A.K.

    2012-01-01

    A common scenario of magnetoelectric coupling in multiferroics is the electric polarization induced by spatially modulated spin structures. It is shown in this paper that the same mechanism works in magnetic dielectrics with inhomogeneous magnetization distribution: the domain walls and magnetic vortexes can be the sources of electric polarization. The electric field driven magnetic domain wall motion is observed in iron garnet films. The electric field induced nucleation of vortex state of magnetic nanodots is theoretically predicted and numerically simulated. From the practical point of view the electric field control of micromagnetic structures suggests a low-power approach for spintronics and magnonics.

  11. Electrical joints in the CMS superconducting magnet

    CERN Document Server

    Farinon, S; Curé, B; Fabbricatore, P; Greco, Michela; Musenich, R

    2002-01-01

    The Compact Muon Solenoid (CMS) is one of the general-purpose detectors to be provided for the LHC project at CERN. The design field of the CMS superconducting magnet is 4 T, the magnetic length is 12.5 m and the free bore is 6 m. The CMS coil consists of five independent modules each containing four winding layers. Each winding layer is composed of a single length of aluminum stabilized and aluminum alloy reinforced conductor. Each of the four conductor lengths within a module will be electrically joined after winding is completed, and each of the five modules will be connected to the magnet bus bars during module assembly. Due to the large dimensions of the conductor and to the high current it carries, the conductor joints are sources of substantial and nontrivial joule heating during nonsteady state operation of the magnet. In addition to steady-state conditions, three transient conditions have been analyzed. The first is related to the current diffusion during a magnet transient that results in a time dep...

  12. Small Satellite Passive Magnetic Attitude Control

    Science.gov (United States)

    Gerhardt, David T.

    Passive Magnetic Attitude Control (PMAC) is capable of aligning a satellite within 5 degrees of the local magnetic field at low resource cost, making it ideal for a small satellite. However, simulation attempts to date have not been able to predict the attitude dynamics at a level sufficient for mission design. Also, some satellites have suffered from degraded performance due to an incomplete understanding of PMAC system design. This dissertation alleviates these issues by discussing the design, inputs, and validation of PMAC systems for small satellites. Design rules for a PMAC system are defined using the Colorado Student Space Weather Experiment (CSSWE) CubeSat as an example. A Multiplicative Extended Kalman Filter (MEKF) is defined for the attitude determination of a PMAC satellite without a rate gyro. After on-orbit calibration of the off-the-shelf magnetometer and photodiodes and an on-orbit fit to the satellite magnetic moment, the MEKF regularly achieves a three sigma attitude uncertainty of 4 degrees or less. CSSWE is found to settle to the magnetic field in seven days, verifying its attitude design requirement. A Helmholtz cage is constructed and used to characterize the CSSWE bar magnet and hysteresis rods both individually and in the flight configuration. Fitted parameters which govern the magnetic material behavior are used as input to a PMAC dynamics simulation. All components of this simulation are described and defined. Simulation-based dynamics analysis shows that certain initial conditions result in abnormally decreased settling times; these cases may be identified by their dynamic response. The simulation output is compared to the MEKF output; the true dynamics are well modeled and the predicted settling time is found to possess a 20 percent error, a significant improvement over prior simulation.

  13. Interference between electric and magnetic concepts in introductory physics

    Directory of Open Access Journals (Sweden)

    Thomas M. Scaife

    2011-03-01

    Full Text Available We investigate student confusion of concepts of electric and magnetic force. At various times during a traditional university-level course, we administered a series of simple questions about the direction of force on a charged particle moving through either an electric or a magnetic field. We find that after electric force instruction but before magnetic force instruction most students answer electric force questions correctly, and we replicate well-known results that many students incorrectly answer that magnetic forces are in the same direction as the magnetic field. After magnetic force instruction, most students answer magnetic force questions correctly, but surprisingly many students incorrectly answer that electric forces are perpendicular to electric fields, as would happen if a student confused electric forces with magnetic forces. As a further indication of interference between electric and magnetic concepts, we also find that students’ responses depend on whether electric or magnetic force questions are posed first, and this effect depends on whether electric or magnetic force was most recently taught.

  14. Nuclear magnetic and electric dipole moments of neon-19

    International Nuclear Information System (INIS)

    MacArthur, D.W.

    1983-01-01

    This thesis presents a detailed discussion of a series of experiments designed to measure the magnetic and electric dipole moments of the β-emitting nucleus 19 Ne. The 19 Ne is generated in the reaction 19 F(p,n) 19 Ne and is polarized by a ''stern-Gerlach'' magnet in a rare gas atomic beams machine. The atoms are stored in a cell for many seconds without depolarizing. The parity violating asymmetry in the β angular distribution is used to monitor the nuclear polarization. The polarized atoms are stored in a cell in a uniform magnetic field. The β-asymmetry is monitored by a pair of β-detectors located on either side of the cell. Transitions between the M/sub J/ = +1/2 and M/sub J/ = -1/2 spin states are induced by an rf field generated by a small Helmholtz coil pair surrounding the cell. Nuclear magnetic resonance lines are observed and the magnetic moment of 19 Ne measured to be μ( 19 Ne) = -1.88542(8)μ/sub N/. A new magnet, cell and detectors were designed to give narrow resonance lines. The equipment is described in detail and several resonance line shapes are discussed. The narrowest resonance line achieved with this system was 0.043 Hz FWHM. This width is primarily due to the 19 Ne lifetime. Pulsed NMR lineshapes were also observed. The narrow NMR lines observed in the previous experiment were then used as a probe to look for an electric dipole moment (EDM) in 19 Ne. Any shift in the resonance frequency correlated with changes in an externally applied electric field would be evidence for an EDM. The EDM of the 19 Ne atom was measured to (7.2 +/- 6.2 X 10 -22 e-cm. This experiment and possible improvements are discussed in detail

  15. Rotating magnetizations in electrical machines: Measurements and modeling

    Directory of Open Access Journals (Sweden)

    Andreas Thul

    2018-05-01

    Full Text Available This paper studies the magnetization process in electrical steel sheets for rotational magnetizations as they occur in the magnetic circuit of electrical machines. A four-pole rotational single sheet tester is used to generate the rotating magnetic flux inside the sample. A field-oriented control scheme is implemented to improve the control performance. The magnetization process of different non-oriented materials is analyzed and compared.

  16. Rotating magnetizations in electrical machines: Measurements and modeling

    Science.gov (United States)

    Thul, Andreas; Steentjes, Simon; Schauerte, Benedikt; Klimczyk, Piotr; Denke, Patrick; Hameyer, Kay

    2018-05-01

    This paper studies the magnetization process in electrical steel sheets for rotational magnetizations as they occur in the magnetic circuit of electrical machines. A four-pole rotational single sheet tester is used to generate the rotating magnetic flux inside the sample. A field-oriented control scheme is implemented to improve the control performance. The magnetization process of different non-oriented materials is analyzed and compared.

  17. Effects of AC Electric Field on Small Laminar Nonpremixed Flames

    KAUST Repository

    Xiong, Yuan

    2015-01-01

    Electric field can be a viable method in controlling various combustion properties. Comparing to traditional actuators, an application of electric field requires very small power consumption. Especially, alternating current (AC) has received

  18. Control of magnetic relaxation by electric-field-induced ferroelectric phase transition and inhomogeneous domain switching

    Energy Technology Data Exchange (ETDEWEB)

    Nan, Tianxiang; Emori, Satoru; Wang, Xinjun; Hu, Zhongqiang; Xie, Li; Gao, Yuan; Lin, Hwaider; Sun, Nian, E-mail: n.sun@neu.edu [Department of Electrical and Computer Engineering, Northeastern University, Boston, Massachusetts 02115 (United States); Peng, Bin; Liu, Ming, E-mail: mingliu@mail.xjtu.edu.cn [Electronic Materials Research Laboratory, Xi' an Jiaotong University, Xi' an 710049 (China); Jiao, Jie; Luo, Haosu [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China); Budil, David [Department of Chemistry, Northeastern University, Boston, Massachusetts 02115 (United States); Jones, John G.; Howe, Brandon M.; Brown, Gail J. [Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States)

    2016-01-04

    Electric-field modulation of magnetism in strain-mediated multiferroic heterostructures is considered a promising scheme for enabling memory and magnetic microwave devices with ultralow power consumption. However, it is not well understood how electric-field-induced strain influences magnetic relaxation, an important physical process for device applications. Here, we investigate resonant magnetization dynamics in ferromagnet/ferroelectric multiferroic heterostructures, FeGaB/PMN-PT and NiFe/PMN-PT, in two distinct strain states provided by electric-field-induced ferroelectric phase transition. The strain not only modifies magnetic anisotropy but also magnetic relaxation. In FeGaB/PMN-PT, we observe a nearly two-fold change in intrinsic Gilbert damping by electric field, which is attributed to strain-induced tuning of spin-orbit coupling. By contrast, a small but measurable change in extrinsic linewidth broadening is attributed to inhomogeneous ferroelastic domain switching during the phase transition of the PMN-PT substrate.

  19. Magnetic self-assembly of small parts

    Science.gov (United States)

    Shetye, Sheetal B.

    used to characterize part-to-substrate MSA. It is shown that the assembly rate and the yield are most dependent on the rotational symmetry of the magnet pattern. Simultaneous and sequential heterogeneous assembly of two types of parts with selective bonding is also demonstrated, with the average assembly yield of 93% in 60 s and 99% in 3.5 min respectively. Finally, MSA with functional electrical interconnects is also demonstrated with a yield of 90.5%.

  20. Magnetic Properties of Electrically Contacted Fe4 Molecular Magnets

    Science.gov (United States)

    Burgess, Jacob; Malavolti, Luigi; Lanzilotto, Valeria; Mannini, Matteo; Totti, Frederico; Ninova, Silviya; Yan, Shichao; Choi, Deung-Jang; Rolf-Pissarczyk, Steffen; Cornia, Andrea; Sessoli, Roberta; Loth, Sebastian

    2015-03-01

    Single molecule magnets (SMMs) are often large and fragile molecules. This poses challenges for the construction of SMM based spintronics. Device geometries with two electronic leads contacting a molecule may be explored via scanning tunneling microscopy (STM). The Fe4 molecule stands out as a robust, thermally evaporable SMM, making it ideal for such an experiment. Here we present the first STM investigations of individual Fe4 molecules thermally evaporated onto a monolayer of Cu2N on a Cu (100) crystal. Using inelastic electron tunneling spectroscopy (IETS), spin excitations in single Fe4 molecules can be detected at meV energies. Analysis using a Spin Hamiltonian allows extraction of magnetic properties of individual Fe4 molecules, and investigation of the influence of the electronic leads. The tip and sample induce small changes in the magnetic properties of Fe4 molecules, making Fe4 a promising candidate for the development of spintronics devices based on SMMs.

  1. PHASE GRADIENT METHOD OF MAGNETIC FIELD MEASUREMENTS IN ELECTRIC VEHICLES

    Directory of Open Access Journals (Sweden)

    N. G. Ptitsyna

    2013-01-01

    Full Text Available Operation of electric and hybrid vehicles demands real time magnetic field control, for instance, for fire and electromagnetic safety. The article deals with a method of magnetic field measurements onboard electric cars taking into account peculiar features of these fields. The method is based on differential methods of measurements, and minimizes the quantity of magnetic sensors.

  2. Electric-magnetic duality in non-Abelian gauge theories

    International Nuclear Information System (INIS)

    Mizrachi, L.

    1982-03-01

    The duality transformation of the vacuum expectation value of the operator which creates magnetic vortices (the 't Hooft loop operator in the Higgs phase) is performed in the radial gauge (xsub(μ)Asub(μ)sup(a)(x)=0). It is found that in the weak coupling region (small g) of a pure Yang-Mills theory the dual operator creates electric vortices whose strength is 1/g. The theory is self dual in this region, and the effective coupling of the dual Lagrangian is 1/g. Thus the above duality transformation reduces to electric-magnetic duality where the electric field in the 't Hooft loop operator transforms into a magnetic field in the dual operator. In a spontaneously broken gauge theory these results are valid only within the region where the vortices (or the monopoles) are concentrated, or in directions of the algebra space of unbroken symmetry, as self duality holds only for this subset of fields. In the strong coupling region a strong coupling expansion in powers of 1/g is suggested. (author)

  3. Magnetic and electrical properties of Cr substituted Ni nano ferrites

    Directory of Open Access Journals (Sweden)

    Katrapally Vijaya Kumar

    2018-03-01

    Full Text Available Nano-ferrites with composition NiCrxFe2-xO4 (where x = 0.1, 0.3, 0.5, 0.7, 0.9, 1.0 were synthesized through citrate-gel auto combustion technique at moderately low temperature. X-ray analysis shows cubic spinel structure single phase without any impurity peak and average crystallite size in the range 8.5–10.5 nm. Magnetic properties were measured using a vibrating sample magnetometer at room temperature in the applied field of ±6 KOe. The obtained M-H loop area is very narrow, hence the synthesized nano ferrites are soft magnetic materials with small coercivity. Magnetic parameters such as saturation magnetization (Ms, coercivity (Hc, remanent magnetization (Mr and residual magnetization were measured and discussed with regard to Cr3+ ion concentration. Electrical properties were measured using two probe method from room temperature to well beyond transition temperature. The DC resistivity variation with temperature shows the semiconductor nature. Resistivity, drift mobility and activation energy values are measured and discussed with regard to composition. The Curie temperature was determined using DC resistivity data and Loria-Sinha method. The observed results can be explained in detail on the basis of composition.

  4. Ferro electricity from magnetic order by neutron measurement

    International Nuclear Information System (INIS)

    Kenzelmann, M.

    2009-01-01

    Magnetic insulators with competing exchange interactions can give rise to strong fluctuations and qualitatively new ground states. The proximity of such systems to quantum critical points can lead to strong cross-coupling between magnetic long-range order and the nuclear lattice. Case in point is a new class of multiferroic materials in which the magnetic and ferroelectric order parameters are directly coupled, and a magnetic field can suppress or switch the electric polarization [1]. Our neutron measurements reveal that ferro electricity is induced by magnetic order and emerges only if the magnetic structure creates a polar axis [2-5]. Our measurements provide evidence that commensurate magnetic order can produce ferro electricity with large electric polarization [6]. The spin dynamics and the field-temperature phase diagram of the ordered phases provide evidence that competing ground states are essential for ferro electricity. (author)

  5. Low frequency electric and magnetic fields

    Science.gov (United States)

    Spaniol, Craig

    1989-01-01

    Following preliminary investigations of the low frequency electric and magnetic fields that may exists in the Earth-ionospheric cavity, measurements were taken with state-of-the art spectrum analyzers. As a follow up to this activity, an investigation was initiated to determine sources and values for possible low frequency signal that would appear in the cavity. The lowest cavity resonance is estimated at about 8 Hz, but lower frequencies may be an important component of our electromagnetic environment. The potential field frequencies produced by the electron were investigated by a classical model that included possible cross coupling of the electric and gravitation fields. During this work, an interesting relationship was found that related the high frequency charge field with the extremely low frequency of the gravitation field. The results of numerical calculations were surprisingly accurate and this area of investigation is continuing. The work toward continued development of a standardized monitoring facility is continuing with the potential of installing the prototype at West Virginia State College early in 1990. This installation would be capable of real time monitoring of ELF signals in the Earth-ionoshpere cavity and would provide some directional information. A high gain, low noise, 1/f frequency corrected preamplifier was designed and tested for the ferrite core magnetic sensor. The potential application of a super conducting sensor for the ELF magnetic field detection is under investigation. It is hoped that a fully operational monitoring network could pinpoint the location of ELF signal sources and provide new information on where these signals originate and what causes them, assuming that they are natural in origin.

  6. Stored Energy of Coupled Electric and Magnetic Currents and the Lower Bound on Q

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.

    2015-01-01

    —New expressions for the stored energy and radiated power of an arbitrary combination of electric and magnetic currents in free space are presented. These expressions enable the calculation of the fundamental lower bound on Q for arbitraryshaped electrically small antennas of finite size....

  7. Magnetic dipole moment of a moving electric dipole

    OpenAIRE

    Hnizdo, V.

    2012-01-01

    The current density of a moving electric dipole is expressed as the sum of polarization and magnetization currents. The magnetic field due to the latter current is that of a magnetic dipole moment that is consistent with the relativistic transformations of the polarization and magnetization of macroscopic electrodynamics.

  8. Computation of the radiation Q of dielectric-loaded electrically small antennas in integral equation formulations

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.

    2016-01-01

    A new technique for estimating the impedance frequency bandwidth of electrically small antennas loaded with magneto-dielectric material from a single-frequency simulation in a surface integral equation solver is presented. The estimate is based on the inverse of the radiation Q computed using newly...... derived expressions for the stored energy and the radiated power of arbitrary coupled electric and magnetic currents in free space....

  9. Magnetic and Electric Properties of , ( Layered Perovskites

    Directory of Open Access Journals (Sweden)

    A. I. Ali

    2013-01-01

    Full Text Available The electric and magnetic properties of layered perovskites have been investigated systematically over the doping range . It was found that both Sr1.5Y0.5CoO4 and Sr1.4Y0.6CoO4 undergo ferromagnetic (FM transition around 145 K and 120 K, respectively. On the other hand, Sr1.3Y0.7CoO4 and Sr1.2Y0.8CoO4 compounds showed paramagnetic behavior over a wide range of temperatures. In addition, spin-glass transition ( was observed at 10 K for Sr1.3Y0.7CoO4. All investigated samples are semiconducting-like within the temperature range of 10–300 K. The temperature dependence of the electrical resistivity, , was described by two-dimensional variable range hopping (2D-VRH model at 50 K < ≤ 300 K. Comparison with other layered perovskites was discussed in this work.

  10. Assessing Students' Conceptual Knowledge of Electricity and Magnetism

    Science.gov (United States)

    McColgan, Michele W.; Finn, Rose A.; Broder, Darren L.; Hassel, George E.

    2017-01-01

    We present the Electricity and Magnetism Conceptual Assessment (EMCA), a new assessment aligned with second-semester introductory physics courses. Topics covered include electrostatics, electric fields, circuits, magnetism, and induction. We have two motives for writing a new assessment. First, we find other assessments such as the Brief…

  11. Fetal exposure to low frequency electric and magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Cech, R; Leitgeb, N; Pediaditis, M [Institute of Clinical Engineering, Graz University of Technology, Inffeldgasse 18, 8010 Graz (Austria)

    2007-02-21

    To investigate the interaction of low frequency electric and magnetic fields with pregnant women and in particular with the fetus, an anatomical voxel model of an 89 kg woman at week 30 of pregnancy was developed. Intracorporal electric current density distributions due to exposure to homogeneous 50 Hz electric and magnetic fields were calculated and results were compared with basic restrictions recommended by ICNIRP guidelines. It could be shown that the basic restriction is met within the central nervous system (CNS) of the mother at exposure to reference level of either electric or magnetic fields. However, within the fetus the basic restriction is considerably exceeded. Revision of reference levels might be necessary.

  12. Fetal exposure to low frequency electric and magnetic fields

    International Nuclear Information System (INIS)

    Cech, R; Leitgeb, N; Pediaditis, M

    2007-01-01

    To investigate the interaction of low frequency electric and magnetic fields with pregnant women and in particular with the fetus, an anatomical voxel model of an 89 kg woman at week 30 of pregnancy was developed. Intracorporal electric current density distributions due to exposure to homogeneous 50 Hz electric and magnetic fields were calculated and results were compared with basic restrictions recommended by ICNIRP guidelines. It could be shown that the basic restriction is met within the central nervous system (CNS) of the mother at exposure to reference level of either electric or magnetic fields. However, within the fetus the basic restriction is considerably exceeded. Revision of reference levels might be necessary

  13. Enhanced Dielectronic Recombination in Crossed Electric and Magnetic Fields

    International Nuclear Information System (INIS)

    Robicheaux, F.; Pindzola, M.S.

    1997-01-01

    The dependence of the dielectronic recombination cross section on crossed electric and magnetic fields is described. The enhancement of this cross section due to a static electric field is further increased when a magnetic field is added perpendicular to the electric field. Calculation of this field induced enhancement is presented for a realistic atomic model, and the mechanism for the enhancement is discussed. copyright 1997 The American Physical Society

  14. Electrical Machines Laminations Magnetic Properties: A Virtual Instrument Laboratory

    Science.gov (United States)

    Martinez-Roman, Javier; Perez-Cruz, Juan; Pineda-Sanchez, Manuel; Puche-Panadero, Ruben; Roger-Folch, Jose; Riera-Guasp, Martin; Sapena-Baño, Angel

    2015-01-01

    Undergraduate courses in electrical machines often include an introduction to their magnetic circuits and to the various magnetic materials used in their construction and their properties. The students must learn to be able to recognize and compare the permeability, saturation, and losses of these magnetic materials, relate each material to its…

  15. Electric-field switching of two-dimensional van der Waals magnets

    Science.gov (United States)

    Jiang, Shengwei; Shan, Jie; Mak, Kin Fai

    2018-05-01

    Controlling magnetism by purely electrical means is a key challenge to better information technology1. A variety of material systems, including ferromagnetic (FM) metals2-4, FM semiconductors5, multiferroics6-8 and magnetoelectric (ME) materials9,10, have been explored for the electric-field control of magnetism. The recent discovery of two-dimensional (2D) van der Waals magnets11,12 has opened a new door for the electrical control of magnetism at the nanometre scale through a van der Waals heterostructure device platform13. Here we demonstrate the control of magnetism in bilayer CrI3, an antiferromagnetic (AFM) semiconductor in its ground state12, by the application of small gate voltages in field-effect devices and the detection of magnetization using magnetic circular dichroism (MCD) microscopy. The applied electric field creates an interlayer potential difference, which results in a large linear ME effect, whose sign depends on the interlayer AFM order. We also achieve a complete and reversible electrical switching between the interlayer AFM and FM states in the vicinity of the interlayer spin-flip transition. The effect originates from the electric-field dependence of the interlayer exchange bias.

  16. Acceleration of auroral particles by magnetic-field aligned electric fields

    International Nuclear Information System (INIS)

    Block, L.P.

    1988-01-01

    Measurements on the S3-3 and Viking satellites appear to show that at least a large fraction of magnetic field-aligned potential drops are made up of multiple double layers. Solitons and double layers in U-shaped potential structures give rise to spiky electric fields also perpendicular to the magnetic field in agreement with satellite measurements. The large scale potential structures associated with inverted V-events are built up of many similar short-lived structures on a small scale. Viking measurements indicate that electric fields parallel to the magnetic field are almost always directed upward

  17. On the polarizability dyadics of electrically small, convex objects

    Science.gov (United States)

    Lakhtakia, Akhlesh

    1993-11-01

    This communication on the polarizability dyadics of electrically small objects of convex shapes has been prompted by a recent paper published by Sihvola and Lindell on the polarizability dyadic of an electrically gyrotropic sphere. A mini-review of recent work on polarizability dyadics is appended.

  18. Tripolar electric field Structure in guide field magnetic reconnection

    Science.gov (United States)

    Fu, Song; Huang, Shiyong; Zhou, Meng; Ni, Binbin; Deng, Xiaohua

    2018-03-01

    It has been shown that the guide field substantially modifies the structure of the reconnection layer. For instance, the Hall magnetic and electric fields are distorted in guide field reconnection compared to reconnection without guide fields (i.e., anti-parallel reconnection). In this paper, we performed 2.5-D electromagnetic full particle simulation to study the electric field structures in magnetic reconnection under different initial guide fields (Bg). Once the amplitude of a guide field exceeds 0.3 times the asymptotic magnetic field B0, the traditional bipolar Hall electric field is clearly replaced by a tripolar electric field, which consists of a newly emerged electric field and the bipolar Hall electric field. The newly emerged electric field is a convective electric field about one ion inertial length away from the neutral sheet. It arises from the disappearance of the Hall electric field due to the substantial modification of the magnetic field and electric current by the imposed guide field. The peak magnitude of this new electric field increases linearly with the increment of guide field strength. Possible applications of these results to space observations are also discussed.

  19. Tripolar electric field Structure in guide field magnetic reconnection

    Directory of Open Access Journals (Sweden)

    S. Fu

    2018-03-01

    Full Text Available It has been shown that the guide field substantially modifies the structure of the reconnection layer. For instance, the Hall magnetic and electric fields are distorted in guide field reconnection compared to reconnection without guide fields (i.e., anti-parallel reconnection. In this paper, we performed 2.5-D electromagnetic full particle simulation to study the electric field structures in magnetic reconnection under different initial guide fields (Bg. Once the amplitude of a guide field exceeds 0.3 times the asymptotic magnetic field B0, the traditional bipolar Hall electric field is clearly replaced by a tripolar electric field, which consists of a newly emerged electric field and the bipolar Hall electric field. The newly emerged electric field is a convective electric field about one ion inertial length away from the neutral sheet. It arises from the disappearance of the Hall electric field due to the substantial modification of the magnetic field and electric current by the imposed guide field. The peak magnitude of this new electric field increases linearly with the increment of guide field strength. Possible applications of these results to space observations are also discussed.

  20. Auroral zone electric fields from DE 1 and 2 at magnetic conjunctions

    Science.gov (United States)

    Weimer, D. R.; Goertz, C. K.; Gurnett, D. A.; Maynard, N. C.; Burch, J. L.

    1985-01-01

    Nearly simultaneous measurements of auroral zone electric fields are obtained by the Dynamics Explorer spacecraft at altitudes below 900 km and above 4,500 km during magnetic conjunctions. The measured electric fields are usually perpendicular to the magnetic field lines. The north-south meridional electric fields are projected to a common altitude by a mapping function which accounts for the convergence of the magnetic field lines. When plotted as a function of invariant latitude, graphs of the projected electric fields measured by both DE-1 and DE-2 show that the large-scale electric field is the same at both altitudes, as expected. Superimposed on the large-scale fields, however, are small-scale features with wavelengths less than 100 km which are larger in magnitude at the higher altitude. Fourier transforms of the electric fields show that the magnitudes depend on wavelength. Outside of the auroral zone the electric field spectrums are nearly identical. But within the auroral zone the high and low altitude electric fields have a ratio which increases with the reciprocal of the wavelength. The small-scale electric field variations are associated with field-aligned currents. These currents are measured with both a plasma instrument and magnetometer on DE-1.

  1. Electric and magnetic dipole moments of the neutron

    International Nuclear Information System (INIS)

    Ramsey, N.F.

    1977-01-01

    Experiments to measure the electric and magnetic dipole moments of the neutron are described. The apparatus used in this experiment is one to measure with high precision the precessional frequency of the neutron spin in a weak magnetic field with a neutron beam magnetic resonance apparatus similar to that used for measuring the magnetic moment of the neutron. Results of the measurement are presented. 52 references

  2. Electrical conductivity and magnetic permeability measurement of case hardened steels

    Science.gov (United States)

    Tian, Yong

    2015-03-01

    For case carburized steels, electrical conductivity and magnetic permeability profiles are needed to develop model-based case depth characterization techniques for the purpose of nondestructive quality control. To obtain fast and accurate measurement of these material properties, four-point potential drop approaches are applied on circular-shaped discs cut from steel rings with different case depths. First, a direct current potential drop (DCPD) approach is applied to measure electrical conductivity. Subsequently, an alternating current potential drop (ACPD) approach is used to measure magnetic permeability. Practical issues in measurement design and implementation are discussed. Depth profiles of electrical conductivity and magnetic permeability are reported.

  3. Electrical insulation for large multiaxis superconducting magnets

    International Nuclear Information System (INIS)

    Harvey, A.R.; Rinde, J.A.

    1975-01-01

    The selection of interturn and interlayer insulation for superconducting magnets is discussed. The magnet problems of the Baseball II device are described. Manufacture of the insulation and radiation damage are mentioned. A planned experimental program is outlined

  4. Electric and magnetic field measurements in an outdoor electric power substation

    Energy Technology Data Exchange (ETDEWEB)

    Safigianni, A.S.; Tsompanidou, C.G. [Democritus Univ. Thrace, Xanthi (Greece). Dept. of Electrical and Computer Engineering

    2006-07-01

    With the ever increasing environmental exposure to man-made electromagnetic fields (EMFs), public concern regarding the potential health hazards of exposure to electric and magnetic fields at extremely low frequencies (ELF) has also increased. This paper examined the ELF fields at a 150/20 kV outdoor electric power substation in Xanthi, Greece. Basic data regarding this substation was provided along with previous relevant research studies. The reference levels for safe general public and occupational exposure according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) was also presented. The instruments used to take the measurements were described and indicative results of the EMFs measurements in the substation were provided. In general, the measured magnetic flux density values were far below the reference level for safe public and occupational exposure. No significant differentiation was noted in these values in relation to body height. However, the levels were found to be in violation in two positions, near the capacitor banks. It was emphasized that these values greatly decreased with distance, and the positions where these high values were measured were not occupied by technicians when the capacitors were under voltage. In addition, it was emphasized that the measured magnetic flux density values were very small in the supervision room, where the supervisor of the substation works and in the ring zone where the public has access. All the measured electric field strength values were below the reference level for safe public and occupational exposure. It was concluded that the measured field values are within recognized guidelines and pose no danger for public or working personnel. 19 refs., 1 tab., 4 figs.

  5. Small-polaron formation and motion in magnetic semiconductors

    International Nuclear Information System (INIS)

    Emin, D.

    1979-01-01

    The fundamental physical processes associated with small-polaron formation are described with various magnetic semi-conductors being cited as examples. Attention is then directed toward the mechanisms of charge transfer and small-polaron hopping motion in magnetic semiconductors

  6. Should we be afraid of magnetic fields related to electricity?

    International Nuclear Information System (INIS)

    Souques, M.

    2009-01-01

    After having recalled that the main sources of 50 Hz electric field are high voltage lines while such a field around any electrical equipment is null because of a presence of insulation, the author comments the magnetic field level at the vicinity of common electrical equipment (refrigerator, hi-fi, computer, television, and so on) and at some distance (30 or 100 meters) of high-voltage and low-voltage lines. She comments the knowledge on the effects of exposure to a 50 Hz magnetic field, and recalls that a publication suggested in 1979 that there was a risk of leukaemia for children living close to electrical lines. More recent studies proposed to apply to magnetic fields an existing classification of products with respect to cancer risk (known, likely, possible, insufficient knowledge, not carcinogen). Some studies put the risk of leukaemia associated to magnetic fields into question again

  7. Strong electric and magnetic dipole excitations in deformed nuclei

    International Nuclear Information System (INIS)

    Kneissl, U.

    1993-01-01

    Systematic nuclear resonance fluorescence (NRF) experiments have been performed at the bremsstrahlung facility of the Stutgart dynamitron to investigate the distribution of magnetic and electric dipole excitations in deformed nuclei

  8. Interferometric methods for mapping static electric and magnetic fields

    DEFF Research Database (Denmark)

    Pozzi, Giulio; Beleggia, Marco; Kasama, Takeshi

    2014-01-01

    The mapping of static electric and magnetic fields using electron probes with a resolution and sensitivity that are sufficient to reveal nanoscale features in materials requires the use of phase-sensitive methods such as the shadow technique, coherent Foucault imaging and the Transport of Intensi......) the model-independent determination of the locations and magnitudes of field sources (electric charges and magnetic dipoles) directly from electron holographic data.......The mapping of static electric and magnetic fields using electron probes with a resolution and sensitivity that are sufficient to reveal nanoscale features in materials requires the use of phase-sensitive methods such as the shadow technique, coherent Foucault imaging and the Transport of Intensity...... on theoretical models that form the basis of the quantitative interpretation of electron holographic data. We review the application of electron holography to a variety of samples (including electric fields associated with p–n junctions in semiconductors, quantized magnetic flux in superconductors...

  9. Small-scale dynamo at low magnetic Prandtl numbers

    Science.gov (United States)

    Schober, Jennifer; Schleicher, Dominik; Bovino, Stefano; Klessen, Ralf S.

    2012-12-01

    The present-day Universe is highly magnetized, even though the first magnetic seed fields were most probably extremely weak. To explain the growth of the magnetic field strength over many orders of magnitude, fast amplification processes need to operate. The most efficient mechanism known today is the small-scale dynamo, which converts turbulent kinetic energy into magnetic energy leading to an exponential growth of the magnetic field. The efficiency of the dynamo depends on the type of turbulence indicated by the slope of the turbulence spectrum v(ℓ)∝ℓϑ, where v(ℓ) is the eddy velocity at a scale ℓ. We explore turbulent spectra ranging from incompressible Kolmogorov turbulence with ϑ=1/3 to highly compressible Burgers turbulence with ϑ=1/2. In this work, we analyze the properties of the small-scale dynamo for low magnetic Prandtl numbers Pm, which denotes the ratio of the magnetic Reynolds number, Rm, to the hydrodynamical one, Re. We solve the Kazantsev equation, which describes the evolution of the small-scale magnetic field, using the WKB approximation. In the limit of low magnetic Prandtl numbers, the growth rate is proportional to Rm(1-ϑ)/(1+ϑ). We furthermore discuss the critical magnetic Reynolds number Rmcrit, which is required for small-scale dynamo action. The value of Rmcrit is roughly 100 for Kolmogorov turbulence and 2700 for Burgers. Furthermore, we discuss that Rmcrit provides a stronger constraint in the limit of low Pm than it does for large Pm. We conclude that the small-scale dynamo can operate in the regime of low magnetic Prandtl numbers if the magnetic Reynolds number is large enough. Thus, the magnetic field amplification on small scales can take place in a broad range of physical environments and amplify week magnetic seed fields on short time scales.

  10. Small-scale dynamo at low magnetic Prandtl numbers.

    Science.gov (United States)

    Schober, Jennifer; Schleicher, Dominik; Bovino, Stefano; Klessen, Ralf S

    2012-12-01

    The present-day Universe is highly magnetized, even though the first magnetic seed fields were most probably extremely weak. To explain the growth of the magnetic field strength over many orders of magnitude, fast amplification processes need to operate. The most efficient mechanism known today is the small-scale dynamo, which converts turbulent kinetic energy into magnetic energy leading to an exponential growth of the magnetic field. The efficiency of the dynamo depends on the type of turbulence indicated by the slope of the turbulence spectrum v(ℓ)∝ℓ^{ϑ}, where v(ℓ) is the eddy velocity at a scale ℓ. We explore turbulent spectra ranging from incompressible Kolmogorov turbulence with ϑ=1/3 to highly compressible Burgers turbulence with ϑ=1/2. In this work, we analyze the properties of the small-scale dynamo for low magnetic Prandtl numbers Pm, which denotes the ratio of the magnetic Reynolds number, Rm, to the hydrodynamical one, Re. We solve the Kazantsev equation, which describes the evolution of the small-scale magnetic field, using the WKB approximation. In the limit of low magnetic Prandtl numbers, the growth rate is proportional to Rm^{(1-ϑ)/(1+ϑ)}. We furthermore discuss the critical magnetic Reynolds number Rm_{crit}, which is required for small-scale dynamo action. The value of Rm_{crit} is roughly 100 for Kolmogorov turbulence and 2700 for Burgers. Furthermore, we discuss that Rm_{crit} provides a stronger constraint in the limit of low Pm than it does for large Pm. We conclude that the small-scale dynamo can operate in the regime of low magnetic Prandtl numbers if the magnetic Reynolds number is large enough. Thus, the magnetic field amplification on small scales can take place in a broad range of physical environments and amplify week magnetic seed fields on short time scales.

  11. Study on a Haptic Sensor Using MCF (Magnetic Compound Fluid) Electric Conductive Rubber

    Science.gov (United States)

    Zheng, Yaoyang; Shimada, Kunio

    To provide a new composite material having a high degree of sensitivity regarding both electrical conduction and temperature for the field of robotics or sensing, we have developed magnetic rubber that contains a network-like magnetic cluster. We compared the temperature response of MCF rubber with others rubbers made under various experimental conditions, allowing us to find an optimum condition for making MCF rubber. The temperature response was obtained by an experimental equation. We also compared the electric conductivity of MCF rubber with that of ordinary electric conductive rubber and found that its electric sensitivity was lower at a small deformation, but increased at larger deformations. Therefore, MCF rubber has proven itself effective as a switching sensor when a small deformation is applied.

  12. Tripolar electric field Structure in guide field magnetic reconnection

    OpenAIRE

    S. Fu; S. Huang; M. Zhou; B. Ni; X. Deng

    2018-01-01

    It has been shown that the guide field substantially modifies the structure of the reconnection layer. For instance, the Hall magnetic and electric fields are distorted in guide field reconnection compared to reconnection without guide fields (i.e., anti-parallel reconnection). In this paper, we performed 2.5-D electromagnetic full particle simulation to study the electric field structures in magnetic reconnection under different initial guide fields (Bg). Once the amplit...

  13. Static and low frequency electric and magnetic fields

    International Nuclear Information System (INIS)

    Thommesen, G.; Tynes, T.

    1994-01-01

    The biological effects of exposure to low frequency electric and magnetic fields are reviewed with the objective of summarizing effects directly relevant to considerations of the health and safety of exposed people. Static and low frequency electric and magnetic fields may elicit biological reactions. Whether exposure to such fields may affect human health at field strengths present in everyday or occupational life is still unsettled. There is unsufficient knowledge to establish any dose concept relevant to health risk. 196 refs., 6 tabs

  14. Magnetic field compatibility of components for ITER electrical distribution systems

    International Nuclear Information System (INIS)

    Hourtoule, J.; Van Houtte, D.; Hertout, P.; Fejoz, P.

    2004-01-01

    The electrical distribution boards and control cubicles, installed inside the ITER Tokamak building, can be subject to a constant or slowly variable magnetic field up to 70 mT, 10 mT/s induced by ITER coils. This is a very unusual environmental condition and there are almost no data available on static magnetic field compatibility for the standard industrial electrical and electronic components that might be used inside standard low voltage distribution boards and standard control boards. CEA has especially taken in charge the test of electronic, control and signal conditioning units. For this purpose a test bed composed of a solenoid and a 30 V, 800 A power supply, has been developed at CEA Cadarache. Its characteristics are the following: - Magnetic field capability: 40 mT; - Variation of field: up to 10 mT/s. Useful dimensions for equipment under test: 500 x 500 x 500 mm. The list of the components to be tested has been identified trying to find common and recent components of different manufacturers. Test procedures have been written following the most relevant IEC standards and manufacturing recommendations and procedures. Magnetic compatibility tests on the basic components of standard low voltage control boards has been performed. All components tested are more or less sensitive to magnetic fields and the effect varies from the simple perturbation of the output signals to the partial destruction of some electronic card. The most sensitive are the ferromagnetic components like small power supplies transformers, relays, on inductors. For power supplies the most important consequence is the increase of the consumption (primary current). For most of the conditioning units the operational limits were found in the range of 30 mT (destruction of materials and overload of the supply) For PLC (Programme Logic Control) central units tested, the limit is in the order of 40 mT (components permanently out of service) Relays are limited to 15 mT (outputs oscillations, no

  15. Nano-Magnets and Additive Manufacturing for Electric Motors

    Science.gov (United States)

    Misra, Ajay K.

    2014-01-01

    High power density is required for application of electric motors in hybrid electric propulsion. Potential path to achieve high power density in electric motors include advanced materials, lightweight thermal management, lightweight structural concepts, high power density power electronics, and advanced manufacturing. This presentation will focus on two key technologies for achieving high power density, advanced magnets and additive manufacturing. The maximum energy product in current magnets is reaching their theoretical limits as a result of material and process improvements. Future improvements in the maximum energy product for magnets can be achieved through development of nanocomposite magnets combining the hard magnetic phase and soft magnetic phase at the nanoscale level. The presentation will provide an overview of the current state of development for nanocomposite magnets and the future path for doubling the maximum energy product. The other part of the presentation will focus on the role of additive manufacturing in fabrication of high power density electric motors. The presentation will highlight the potential opportunities for applying additive manufacturing to fabricate electric motors.

  16. Electrical protection of superconducting magnet systems

    International Nuclear Information System (INIS)

    Sutter, D.F.; Flora, R.H.

    1975-01-01

    The problem of dissipating the energy stored in the field of a superconducting magnet when a quench occurs has received considerable study. However, when the magnet becomes a system 4 miles in length whose normal operation is an ac mode, some re-examination of standard techniques for dissipating energy outside the magnets is in order. Data accumulated in the Fermilab Energy Doubler magnet development program shows that heating associated with the temporal and spatial development of quenches is highly localized and can result in temperatures damaging to the superconducting wire. The design and operation are discussed for several energy dumping schemes, compatible with the operation of ac superconducting magnets, wherein more than 70 percent of the stored energy can be dissipated outside the magnet. Instrumentation to detect quenches early in their development and circuits for dumping the field energy are described, and representative operating performance data for the dump circuits and data showing temporal development of quenches are presented. (auth)

  17. Linear magnetic motor/generator. [to generate electric energy using magnetic flux for spacecraft power supply

    Science.gov (United States)

    Studer, P. A. (Inventor)

    1982-01-01

    A linear magnetic motor/generator is disclosed which uses magnetic flux to provide mechanical motion or electrical energy. The linear magnetic motor/generator includes an axially movable actuator mechanism. A permament magnet mechanism defines a first magnetic flux path which passes through a first end portion of the actuator mechanism. Another permament magnet mechanism defines a second magnetic flux path which passes through a second end portion of the actuator mechanism. A drive coil defines a third magnetic flux path passing through a third central portion of the actuator mechanism. A drive coil selectively adds magnetic flux to and subtracts magnetic flux from magnetic flux flowing in the first and second magnetic flux path.

  18. Measurement of AC electrical characteristics of SSC superconducting dipole magnets

    International Nuclear Information System (INIS)

    Smedley, K.M.; Shafer, R.E.

    1992-01-01

    Experiments were conducted to measure the AC electrical characteristics of SSC superconducting dipole magnets over the frequency range of 0.1 Hz to 10 kHz. A magnet equivalent circuit representing the magnet DC inductance, eddy current losses, coil-to-ground and turn-to-turn capacitance, was synthesized from the experimental data. This magnet equivalent circuit can be used to predict the current ripple distribution along the superconducting magnet string and can provide dynamic information for the design of the collider current regulation loop

  19. Electric machines with axial magnetic flux

    Science.gov (United States)

    Nuca, I.; Ambros, T.; Burduniuc, M.; Deaconu, S. I.; Turcanu, A.

    2018-01-01

    The paper contains information on the performance of axial machines compared to cylindrical ones. At the same time, various constructive schemes of synchronous electromechanical converters with permanent magnets and asynchronous with short-circuited rotor are presented. In the developed constructions, the aim is to maximize the usage of the material of the stator windings. The design elements of the axial machine magnetic system are presented. The FEMM application depicted the array of the magnetic field of an axial machine.

  20. ion in crossed gradient electric and magnetic fields

    Indian Academy of Sciences (India)

    Photodetachment cross-section for variousexternal fields and the laser polarization are calculated and displayed. A comparison with the photodetachment cross-section in crossed uniform electric and magnetic fields or in a single gradient electric field has been made.The agreement of our results with the above two special ...

  1. Auroral-zone electric fields from DE-1 and -2 at magnetic conjuctions

    International Nuclear Information System (INIS)

    Weimer, D.R.

    1984-01-01

    Nearly simultaneous measurements of auroral zone electric fields are obtained by the Dynamics Explorer spacecraft at altitudes below 900 km and above 4500 km during magnetic conjuctions. The measured electric fields are approximately perpendicular to the magnetic field lines. The north-south meridional electric fields are projected to a common altitude by a mapping function. When plotted as a function of invariant latitude, graphs of the projected electric fields measured by DE-1 and DE-2 show that the large-scale electric field is the same at both altitudes. However, superimposed on the large-scale fields are small-scale features with wavelengths less than 100 km which are larger in magnitude at the higher altitude. Fourier transforms of the electric fields show that the magnitudes depend on wavelength. Outside of the auroral zone the electric field spectrums are nearly identical. But within the auroral zone the spectrums of the high and low altitude electric fields have a ratio which increases with the reciprocal of the wavelength. The small-scale electric field variations are associated with field-aligned currents. These currents are measured with both a plasma instrument and magnetometer on DE-1

  2. Electric Propellant Solid Rocket Motor Thruster Results Enabling Small Satellites

    OpenAIRE

    Koehler, Frederick; Langhenry, Mark; Summers, Matt; Villarreal, James; Villarreal, Thomas

    2017-01-01

    Raytheon Missile Systems has developed and tested true on/off/restart solid propellant thrusters which are controlled only by electrical current. This new patented class of energetic rocket propellant is safe, controllable and simple. The range of applications for this game changing technology includes attitude control systems and a safe alternative to higher impulse space satellite thrusters. Described herein are descriptions and performance data for several small electric propellant solid r...

  3. On a Correlation between the Ionospheric Electric Field and the Time Derivative of the Magnetic Field

    Directory of Open Access Journals (Sweden)

    R. R. Ilma

    2012-01-01

    Full Text Available A correlation of the ionospheric electric field and the time derivative of the magnetic field was noticed over thirty years ago and has yet to be explained. Here we report on another set of examples during the superstorm of November 2004. The electric field in the equatorial ionosphere, measured with the Jicamarca incoherent scatter radar, exhibited a 3 mV/m electric field pulse that was not seen in the interplanetary medium. It was, however, accompanied by a correlation with the time derivative of the magnetic field measured at two points in Peru. Our inclination was to assume that the field was inductive. However, the time scale of the pulse was too short for the magnetic field to penetrate the crust of the Earth. This means that the area threaded by ∂B/∂t was too small to create the observed electric field by induction. We suggest that the effect was caused by a modulation of the ring current location relative to the Earth due to the electric field. This electric field is required, as the magnetic field lines are considered frozen into the plasma in the magnetosphere. The closer location of the ring current to the Earth in turn increased the magnetic field at the surface.

  4. Magnetic and electric dipole constraints on extra dimensions and magnetic fluxes

    International Nuclear Information System (INIS)

    Roy, Aaron J.; Bander, Myron

    2009-01-01

    The propagation of charged particles and gauge fields in a compact extra dimension contributes to g-2 of the charged particles. In addition, a magnetic flux threading this extra dimension generates an electric dipole moment for these particles. We present constraints on the compactification size and on the possible magnetic flux imposed by the comparison of data and theory of the magnetic moment of the muon and from limits on the electric dipole moments of the muon, neutron and electron

  5. Electrically small circularly polarized spherical antenna with air core

    DEFF Research Database (Denmark)

    Kim, O. S.

    2013-01-01

    An electrically small circularly polarized self-resonant spherical antenna with air core is presented. The antenna is a modified multiarm spherical helix exciting TM10 and TE10 spherical modes with equal radiated power, and thus yielding perfect circular polarization over the entire far......-field sphere (except the polar regions, where the radiation is low). The self-resonance is achieved by exciting higher-order TM modes, which provide the necessary electric stored energy in the near-field, while contributing negligibly to the far-field radiation of the antenna. The antenna has electrical size...

  6. Magnetic and electrical properties of ITER vacuum vessel steels

    International Nuclear Information System (INIS)

    Mergia, K.; Apostolopoulos, G.; Gjoka, M.; Niarchos, D.

    2007-01-01

    Full text of publication follows: Ferritic steel AISI 430 is a candidate material for the lTER vacuum vessel which will be used to limit the ripple in the toroidal magnetic field. The magnetic and electrical properties and their temperature dependence in the temperature range 300 - 900 K of AISI 430 ferritic stainless steels are presented. The temperature variation of the coercive field, remanence and saturation magnetization as well as electrical resistivity and the effect of annealing on these properties is discussed. (authors)

  7. Development of electric discharge equipment for small specimen sampling

    International Nuclear Information System (INIS)

    Okamoto, Koji; Kitagawa, Hideaki; Kusumoto, Junichi; Kanaya, Akihiro; Kobayashi, Toshimi

    2009-01-01

    We have developed the on-site electric discharge sampling equipment that can effectively take samples such as small specimens from the surface portion of the plant components. Compared with the conventional sampling equipment, our sampling equipment can take samples that are thinner in depth and larger in area. In addition, the affection to the equipment can be held down to the minimum, and the thermally-affected zone of the material due to electric discharge is small, which is to be ignored. Therefore, our equipment is excellent in taking samples for various tests such as residual life evaluation.

  8. Nuclear Power as an Option in Electrical Generation Planning for Small Economy and Electricity Grid

    International Nuclear Information System (INIS)

    Tomsic, Z.

    2012-01-01

    Implementing a NPP in countries with relatively small total GDP (small economy) and usually with small electricity grid face two major problems and constrains: the ability to obtain the considerable financial resources required on reasonable terms and to connect large NPP to small electricity grid. Nuclear generation financing in developing countries involves complex issues that need to be fully understood and dealt with by all the parties involved. The main topics covered by paper will be the: special circumstances related to the financing of NPP, costs and economic feasibility of NPP, conventional approaches for financing power generation projects in developing countries, alternative approaches for mobilizing financial resources. The safe and economic operation of a nuclear power plant (NPP) requires the plant to be connected to an electrical grid system that has adequate capacity for exporting the power from the NPP, and for providing a reliable electrical supply to the NPP for safe start-up, operation and normal or emergency shut-down of the plant. Connection of any large new power plant to the electrical grid system in a country may require significant modification and strengthening of the grid system, but for NPPs there may be added requirements to the structure of the grid system and the way it is controlled and maintained to ensure adequate reliability. Paper shows the comparative assesment of differrent base load technologies as an option in electrical generation planning for small economy and electricity grid.(author).

  9. Electric vehicles, magnetic levitation and superconductive levitation in Japan

    International Nuclear Information System (INIS)

    Wyczalek, F.A.

    1988-01-01

    This is a technological assessment of electric automotive vehicles, high speed magnetic levitation trains and hyperspeed superconductive magnetic levitation trains in Japan. It includes conventional battery electric vehicles for the automotive application, conventional magnetic levitation trains with peak speeds of 300 km/h and superconductive levitation trains capable of speeds over 500 km/h in transcontinental service. These electric vehicles have been under development since 1971 and are now considered ready for introduction into intercity commercial service. Conventional magnetic levitation trains are targeted to connect New Chitose International Airport with Sapporo and shorter connections in LasVegas, Philadelphia and Miami. The first superconductive train is planned for the Osaka to Tokyo link by the year 2000, a distance of 515 km. The initial step has been taken with approval of funding for the first five year phase of construction beginning with the Kansai project near Osaka

  10. Magnetically insulated fission electric cells for direct energy conversion

    International Nuclear Information System (INIS)

    Slutz, S.A.; Seidel, D.B.; Lipinski, R.J.; Rochau, G.E.; Brown, L.C.

    2003-01-01

    The principles of fission electric cells are reviewed. A detailed Monte Carlo model of the efficiency of a fission electric cell is presented and a theory of magnetically insulated fission electric cells (MIFECs) is developed. It is shown that the low operating voltages observed in previous MIFEC experiments were due to nonoptimal magnetic field profiles. Improved magnetic field profiles are presented. It is further shown that the large electric field present in a MIFEC limits the structure of the cathode and can lead to a displacement instability of the cathode toward the anode. This instability places constraints on the number of cells that can be strung together without some external cathode support. The large electric field stress also leads to electrical surface breakdown of the cathode. It is shown that this leads to the formation of a virtual cathode resulting in geometry constraints for spherical cells. Finally it is shown that the requirements of magnetic insulation and high efficiency leads to very low average density of the fissile material. Thus a reactor using fission electric cells for efficient direct energy conversion will be large and require a very large number of cells. This could be mitigated somewhat by the use of exotic fuels

  11. Magnetic field generation device for magnetohydrodynamic electric power generation

    International Nuclear Information System (INIS)

    Kuriyama, Yoshihiko.

    1993-01-01

    An existent magnetic field generation device for magnetohydrodynamic electric power generation comprises at least a pair of permanent magnets disposed to an inner circumferential surface of a yoke having such a cross sectional area that two pairs of parallel sides are present, in which different magnetic poles are opposed while interposing a flow channel for a conductive fluid therebetween. Then, first permanent magnets which generate main magnetic fields are disposed each at a gap sandwiching a plane surface including a center axis of a flow channel for the conductive fluid. Second permanent magnets which generate auxiliary magnetic fields are disposed to an inner circumferential surface of a yoke intersecting the yoke to which the first permanent magnets are disposed. The magnetic poles on the side of the flow channel for the second permanent magnets have identical polarity with that of the magnetic poles of the adjacent first permanent magnets. As a result, a magnetic flux density in the flow channel for the conductive fluid can be kept homogeneous and at a high level from a position of the axial line of the flow channel to the outer circumference, thereby enabling to remarkably improve a power generation efficiency. (N.H.)

  12. Magnetic emission ranking of electrical appliances. A comprehensive market survey

    International Nuclear Information System (INIS)

    Leitgeb, N.; Cech, R.; Schroettner, J.; Lehofer, P.; Schmidpeter, U.; Rampetsreiter, M.

    2008-01-01

    Over the last decades emissions of magnetic fields from electric appliances have considerably changed. Based on a comprehensive market survey it could be shown that today magnetic emissions are usually characterised by complex frequency spectra while single-frequency emissions have become rare. Therefore, spectral assessment procedures play a critical role. Compared to frequency-weighted equivalent magnetic induction, rms values may underestimate emissions up to two orders of magnitudes. Therefore, rms measurements are not suitable and emission-ranking lists of devices need revision. Surface hot-spot measurements at nominal load conditions and 230 V/50 Hz supply involved 1146 new electrical devices of 166 different categories. High emissions were not rare. Magnetic emissions of devices of 73 different categories exceeded reference levels up to almost two orders of magnitudes above reference levels. Maximum values were higher than reported so far. Magnetic emissions were high enough to make even conformity with existing basic restrictions not self-evident. (authors)

  13. Electrical detection of magnetization dynamics via spin rectification effects

    Energy Technology Data Exchange (ETDEWEB)

    Harder, Michael, E-mail: michael.harder@umanitoba.ca; Gui, Yongsheng, E-mail: ysgui@physics.umanitoba.ca; Hu, Can-Ming, E-mail: hu@physics.umanitoba.ca

    2016-11-23

    The purpose of this article is to review the current status of a frontier in dynamic spintronics and contemporary magnetism, in which much progress has been made in the past decade, based on the creation of a variety of micro and nanostructured devices that enable electrical detection of magnetization dynamics. The primary focus is on the physics of spin rectification effects, which are well suited for studying magnetization dynamics and spin transport in a variety of magnetic materials and spintronic devices. Intended to be intelligible to a broad audience, the paper begins with a pedagogical introduction, comparing the methods of electrical detection of charge and spin dynamics in semiconductors and magnetic materials respectively. After that it provides a comprehensive account of the theoretical study of both the angular dependence and line shape of electrically detected ferromagnetic resonance (FMR), which is summarized in a handbook format easy to be used for analysing experimental data. We then review and examine the similarity and differences of various spin rectification effects found in ferromagnetic films, magnetic bilayers and magnetic tunnel junctions, including a discussion of how to properly distinguish spin rectification from the spin pumping/inverse spin Hall effect generated voltage. After this we review the broad applications of rectification effects for studying spin waves, nonlinear dynamics, domain wall dynamics, spin current, and microwave imaging. We also discuss spin rectification in ferromagnetic semiconductors. The paper concludes with both historical and future perspectives, by summarizing and comparing three generations of FMR spectroscopy which have been developed for studying magnetization dynamics.

  14. Magnetic resonance electrical impedance tomography for determining electric field distribution during electroporation

    International Nuclear Information System (INIS)

    Kranjc, Matej; Miklavcic, Damijan; Bajd, Franci; Serša, Igor

    2013-01-01

    Electroporation is a phenomenon caused by externally applied electric field to cells that results in an increase of cell membrane permeability to various molecules. Accurate coverage of the tissue with a sufficiently large electric field presents one of the most important conditions for successful membrane permeabilization. Applications based on electroporation would greatly benefit with a method for monitoring the electric field, especially if it could be done in situ. As the membrane electroporation is a consequence of an induced transmembrane potential, which is directly proportional to the local electric field, we have been investigating current density imaging and magnetic resonance electrical impedance tomography techniques to determine the electric field distribution during electroporation. In this paper, we present comparison of current density and electric field distribution in an agar phantom and in a liver tissue exposed to electroporation pulses. As expected, a region of increased electrical conductivity was observed in the liver tissue exposed to sufficiently high electric field but not in agar phantom.

  15. TPC track distortions: correction maps for magnetic and static electric inhomogeneities

    CERN Document Server

    Dydak, F; Nefedov, Y

    2003-01-01

    Inhomogeneities of the magnetic and electric fields in the active TPC volume lead to displacements of cluster coordinates, and therefore to track distortions. In case of good data taking conditions, the largest effects are expected from the inhomogeneity of the solenoidal magnetic field, and from a distortion of the electric field arising from a high voltage misalignment between the outer and inner field cages. Both effects are stable over the entire HARP data taking. The displacements are large compared to the azimuthal coordinate resolution but can be corrected with sufficient precision, except at small TPC radius. The high voltage misalignment between the outer and inner field cages is identified as the likely primary cause of sagitta distortions of TPC tracks. The position and the length of the target plays an important role. Based on a detailed modelling of the magnetic and static electric field inhomogeneities, precise correction maps for both effects have been calculated. Predictions from the correctio...

  16. 50-60 Hz electric and magnetic field effects on cognitive function in humans: A review

    International Nuclear Information System (INIS)

    Crasson, M.

    2003-01-01

    This paper reviews the effect of 50-60 Hz weak electric, magnetic and combined electric and magnetic field exposure on cognitive functions such as memory, attention, information processing and time perception, as determined by electroencephalographic methods and performance measures. Overall, laboratory studies, which have investigated the acute effects of power frequency fields on cognitive functioning in humans are heterogeneous, in terms of both electric and magnetic field (EMF) exposure and the experimental design and measures used. Results are inconsistent and difficult to interpret with regard to functional relevance for possible health risks. Statistically significant differences between field and control exposure, when they are found, are small, subtle, transitory, without any clear dose-response relationship and difficult to reproduce. The human performance or event related potentials (ERPs) measures that might specifically be affected by EMF exposure, as well as a possible cerebral structure or function that could be more sensitive to EMF, cannot be better determined. (author)

  17. Light scattering of rectangular slot antennas: parallel magnetic vector vs perpendicular electric vector

    Science.gov (United States)

    Lee, Dukhyung; Kim, Dai-Sik

    2016-01-01

    We study light scattering off rectangular slot nano antennas on a metal film varying incident polarization and incident angle, to examine which field vector of light is more important: electric vector perpendicular to, versus magnetic vector parallel to the long axis of the rectangle. While vector Babinet’s principle would prefer magnetic field along the long axis for optimizing slot antenna function, convention and intuition most often refer to the electric field perpendicular to it. Here, we demonstrate experimentally that in accordance with vector Babinet’s principle, the incident magnetic vector parallel to the long axis is the dominant component, with the perpendicular incident electric field making a small contribution of the factor of 1/|ε|, the reciprocal of the absolute value of the dielectric constant of the metal, owing to the non-perfectness of metals at optical frequencies.

  18. Quench tests of Nb3Al small racetrack magnets

    International Nuclear Information System (INIS)

    Yamada, R.; Kikuchi, A.; Tartaglia, Michael Albert; Ambrosio, G.; Andreev, N.; Barzi, E.; Carcagno, R.; Feher, S.; Kashikhin, V.V.; Kotelnikov, S.; Lamm, Michael J.; Fermilab; NIMC, Tsukuba; KEK, Tsukuba

    2007-01-01

    Two Cu stabilized Nb3Al strands, F1 (Nb matrixed) and F3 (Ta matrixed), have been made at NIMS and their Rutherford cables were made at Fermilab in collaboration with NIMS. A Small Race-track magnet using F1 Rutherford cable, the first Nb3Al dipole magnet in the world, was constructed and tested to full current at Fermilab. This magnet was tested extensively to full short sample data and its quench characteristics were studied and reported. The 3-D magnetic field calculation was done with ANSYS to find the peak field. The quench characteristics of the magnet are explained with the characteristics of the Nb3Al strand and Rutherford cable. The other Small Race-track magnet using Ta matrixed F3 strand was constructed and will be tested in the near future. The advantages and disadvantages of these Nb3Al cables are discussed

  19. Quench tests of Nb3Al small racetrack magnets

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, R.; Kikuchi, A.; Tartaglia, Michael Albert; Ambrosio, G.; Andreev, N.; Barzi, E.; Carcagno, R.; Feher, S.; Kashikhin, V.V.; Kotelnikov, S.; Lamm, Michael J.; /Fermilab /NIMC, Tsukuba /KEK, Tsukuba

    2007-08-01

    Two Cu stabilized Nb3Al strands, F1 (Nb matrixed) and F3 (Ta matrixed), have been made at NIMS and their Rutherford cables were made at Fermilab in collaboration with NIMS. A Small Race-track magnet using F1 Rutherford cable, the first Nb3Al dipole magnet in the world, was constructed and tested to full current at Fermilab. This magnet was tested extensively to full short sample data and its quench characteristics were studied and reported. The 3-D magnetic field calculation was done with ANSYS to find the peak field. The quench characteristics of the magnet are explained with the characteristics of the Nb3Al strand and Rutherford cable. The other Small Race-track magnet using Ta matrixed F3 strand was constructed and will be tested in the near future. The advantages and disadvantages of these Nb3Al cables are discussed.

  20. Rapid Prototyping of Electrically Small Spherical Wire Antennas

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.

    2014-01-01

    It is shown how modern rapid prototyping technologies can be applied for quick and inexpensive, but still accurate, fabrication of electrically small wire antennas. A well known folded spherical helix antenna and a novel spherical zigzag antenna have been fabricated and tested, exhibiting...

  1. Electrical characterization of small area devices for manufacturing

    International Nuclear Information System (INIS)

    Enzenroth, R.A.; Davies, A.; Reed, S.

    2011-01-01

    Uniformity of electrical performance is critical for thin film modules. The more uniformly that all areas of the module perform the better the overall efficiency will be. Total module performance tends towards the average of localized performance, skewed slightly lower by the width of localized performance distribution. Measurement of overall module efficiency does not give information about performance uniformity. Use of small area devices (SAD's) defined from the module allow standard electrical measurements including light and dark current-voltage (IV/JV) and quantum efficiency to be performed on a small scale. Data from these measurements allows mapping of electrical performance across the module. The structure of types of SAD's is discussed and some examples of efficiency data from JV measurements as used in the optimization of a thin film module manufacturing line are presented. Also a brief discussion of statistical analysis of the data is included.

  2. Small Wind Electric Systems: A U.S. Consumer's Guide

    International Nuclear Information System (INIS)

    O'Dell, K.

    2001-01-01

    The U.S. Consumer's Guide for Small Wind Electric systems provides consumers with enough information to help them determine if a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include: how to make your home more energy efficient, how to choose the right size turbine, the parts of a wind electric system, determining if there is enough wind resource on your site, choosing the best site for your turbine, connecting your system to the utility grid, and if it's possible to become independent of the utility grid using wind energy

  3. Small Wind Electric Systems An Alaska Consumer's Guide

    International Nuclear Information System (INIS)

    O'Dell, K.

    2001-01-01

    The Alaska Consumer's Guide for Small Wind Electric Systems provides consumers with enough information to help them determine if a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include: how to make your home more energy efficient, how to choose the right size turbine, the parts of a wind electric system, determining if there is enough wind resource on your site, choosing the best site for your turbine, connecting your system to the utility grid, and if it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a state wind resource map and a list of state incentives and state contacts for more information

  4. Small Wind Electric Systems: A Kansas Consumer's Guide

    International Nuclear Information System (INIS)

    O'Dell, K.

    2001-01-01

    The Kansas Consumer's Guide for Small Wind Electric Systems provides consumers with enough information to help them determine if a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include: how to make your home more energy efficient, how to choose the right size turbine, the parts of a wind electric system, determining if there is enough wind resource on your site, choosing the best site for your turbine, connecting your system to the utility grid, and if it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of state incentives and state contacts for more information

  5. Small Wind Electric Systems: A New Mexico Consumer's Guide

    International Nuclear Information System (INIS)

    O'Dell, K.

    2001-01-01

    The New Mexico Consumer's Guide for Small Wind Electric Systems provides consumers with enough information to help them determine if a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include: how to make your home more energy efficient, how to choose the right size turbine, the parts of a wind electric system, determining if there is enough wind resource on your site, choosing the best site for your turbine, connecting your system to the utility grid, and if it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a state wind resource map and a list of state incentives and state contacts for more information

  6. Small Wind Electric Systems: A Vermont Consumer's Guide

    International Nuclear Information System (INIS)

    O'Dell, K.

    2001-01-01

    The Vermont Consumer's Guide for Small Wind Electric Systems provides consumers with enough information to help them determine if a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include: how to make your home more energy efficient, how to choose the right size turbine, the parts of a wind electric system, determining if there is enough wind resource on your site, choosing the best site for your turbine, connecting your system to the utility grid, and if it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a state wind resource map and a list of state incentives and state contacts for more information

  7. Small Wind Electric Systems: A South Dakota Consumer's Guide

    International Nuclear Information System (INIS)

    O'Dell, K.

    2001-01-01

    The South Dakota Consumer's Guide for Small Wind Electric Systems provides consumers with enough information to help them determine if a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include: how to make your home more energy efficient, how to choose the right size turbine, the parts of a wind electric system, determining if there is enough wind resource on your site, choosing the best site for your turbine, connecting your system to the utility grid, and if it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a state wind resource map and a list of state incentives and state contacts for more information

  8. Plasma Flows in Crossed Magnetic and Electric Fields

    International Nuclear Information System (INIS)

    Belikov, A.G.

    2005-01-01

    The effect of the magnitude and direction of an external electric field on the plasma flowing through a magnetic barrier is studied by numerically solving two-fluid MHD equations. The drift velocity of the plasma flow and the distribution of the flow electrons over transverse velocities are found to depend on the magnitude and direction of the electric field. It is shown that the direction of the induced longitudinal electric field is determined by the direction of the external field and that the electric current generated by the plasma flow significantly disturbs the barrier field

  9. Pattern of mathematic representation ability in magnetic electricity problem

    Science.gov (United States)

    Hau, R. R. H.; Marwoto, P.; Putra, N. M. D.

    2018-03-01

    The mathematic representation ability in solving magnetic electricity problem gives information about the way students understand magnetic electricity. Students have varied mathematic representation pattern ability in solving magnetic electricity problem. This study aims to determine the pattern of students' mathematic representation ability in solving magnet electrical problems.The research method used is qualitative. The subject of this study is the fourth semester students of UNNES Physics Education Study Program. The data collection is done by giving a description test that refers to the test of mathematical representation ability and interview about field line topic and Gauss law. The result of data analysis of student's mathematical representation ability in solving magnet electric problem is categorized into high, medium and low category. The ability of mathematical representations in the high category tends to use a pattern of making known and asked symbols, writing equations, using quantities of physics, substituting quantities into equations, performing calculations and final answers. The ability of mathematical representation in the medium category tends to use several patterns of writing the known symbols, writing equations, using quantities of physics, substituting quantities into equations, performing calculations and final answers. The ability of mathematical representations in the low category tends to use several patterns of making known symbols, writing equations, substituting quantities into equations, performing calculations and final answer.

  10. Sparse Reconstruction of Electric Fields from Radial Magnetic Data

    International Nuclear Information System (INIS)

    Yeates, Anthony R.

    2017-01-01

    Accurate estimates of the horizontal electric field on the Sun’s visible surface are important not only for estimating the Poynting flux of magnetic energy into the corona but also for driving time-dependent magnetohydrodynamic models of the corona. In this paper, a method is developed for estimating the horizontal electric field from a sequence of radial-component magnetic field maps. This problem of inverting Faraday’s law has no unique solution. Unfortunately, the simplest solution (a divergence-free electric field) is not realistically localized in regions of nonzero magnetic field, as would be expected from Ohm’s law. Our new method generates instead a localized solution, using a basis pursuit algorithm to find a sparse solution for the electric field. The method is shown to perform well on test cases where the input magnetic maps are flux balanced in both Cartesian and spherical geometries. However, we show that if the input maps have a significant imbalance of flux—usually arising from data assimilation—then it is not possible to find a localized, realistic, electric field solution. This is the main obstacle to driving coronal models from time sequences of solar surface magnetic maps.

  11. Sparse Reconstruction of Electric Fields from Radial Magnetic Data

    Energy Technology Data Exchange (ETDEWEB)

    Yeates, Anthony R. [Department of Mathematical Sciences, Durham University, Durham, DH1 3LE (United Kingdom)

    2017-02-10

    Accurate estimates of the horizontal electric field on the Sun’s visible surface are important not only for estimating the Poynting flux of magnetic energy into the corona but also for driving time-dependent magnetohydrodynamic models of the corona. In this paper, a method is developed for estimating the horizontal electric field from a sequence of radial-component magnetic field maps. This problem of inverting Faraday’s law has no unique solution. Unfortunately, the simplest solution (a divergence-free electric field) is not realistically localized in regions of nonzero magnetic field, as would be expected from Ohm’s law. Our new method generates instead a localized solution, using a basis pursuit algorithm to find a sparse solution for the electric field. The method is shown to perform well on test cases where the input magnetic maps are flux balanced in both Cartesian and spherical geometries. However, we show that if the input maps have a significant imbalance of flux—usually arising from data assimilation—then it is not possible to find a localized, realistic, electric field solution. This is the main obstacle to driving coronal models from time sequences of solar surface magnetic maps.

  12. Electric control of wave vector filtering in a hybrid magnetic-electric-barrier nanostructure

    Science.gov (United States)

    Kong, Yong-Hong; Lu, Ke-Yu; He, Ya-Ping; Liu, Xu-Hui; Fu, Xi; Li, Ai-Hua

    2018-06-01

    We theoretically investigate how to manipulate the wave vector filtering effect by a traverse electric field for electrons across a hybrid magnetic-electric-barrier nanostructure, which can be experimentally realized by depositing a ferromagnetic stripe and a Schottky-metal stripe on top and bottom of a GaAs/Al x Ga1- x As heterostructure, respectively. The wave vector filtering effect is found to be related closely to the applied electric field. Moreover, the wave vector filtering efficiency can be manipulated by changing direction or adjusting strength of the traverse electric field. Therefore, such a nanostructure can be employed as an electrically controllable electron-momentum filter for nanoelectronics applications.

  13. Electric-Field-Induced Superconductivity Detected by Magnetization Measurements of an Electric-Double-Layer Capacitor

    NARCIS (Netherlands)

    Kasahara, Yuichi; Nishijima, Takahiro; Sato, Tatsuya; Takeuchi, Yuki; Ye, Jianting; Yuan, Hongtao; Shimotani, Hidekazu; Iwasa, Yoshihiro

    We report evidence for superconductivity induced by the application of strong electric fields onto the surface of a band insulator, ZrNCl, provided by the observation of a shielding diamagnetic signal. We introduced an electric-double-layer capacitor configuration and in situ magnetization

  14. A kitchen course in electricity and magnetism

    CERN Document Server

    Nightingale, David

    2014-01-01

    Electricity is all around us: cars, telephones, computers, lights -- the modern world runs entirely on electrons. But what are electrons? How do they behave? How do we control them? This book will show you how to build a battery, detect static electricity and construct a basic current meter, all using common items from your kitchen. Along the way you'll learn about the meaning of ""voltage"" and ""current"", what makes an LED work and the difference between AC and DC. The last chapter uses transistors -- the basic building blocks of every computer -- for lots of interesting experiments. With p

  15. The relationship between anatomically correct electric and magnetic field dosimetry and published electric and magnetic field exposure limits

    International Nuclear Information System (INIS)

    Kavet, R.; Dovan, T.; Patrick Reilly, J.

    2012-01-01

    Electric and magnetic field exposure limits published by International Commission for Non-Ionizing Radiation Protection and Inst. of Electrical and Electronics Engineers are aimed at protection against adverse electro-stimulation, which may occur by direct coupling to excitable tissue and, in the case of electric fields, through indirect means associated with surface charge effects (e.g. hair vibration, skin sensations), spark discharge and contact current. For direct coupling, the basic restriction (BR) specifies the not-to-be-exceeded induced electric field. The key results of anatomically based electric and magnetic field dosimetry studies and the relevant characteristics of excitable tissue were first identified. This permitted us to assess the electric and magnetic field exposure levels that induce dose in tissue equal to the basic restrictions, and the relationships of those exposure levels to the limits now in effect. We identify scenarios in which direct coupling of electric fields to peripheral nerve could be a determining factor for electric field limits. (authors)

  16. Gilbert's De Magnete: An early study of magnetism and electricity

    Science.gov (United States)

    Malin, Stuart; Barraclough, David

    Four hundred years might seem an excessively long time to wait for a book review, but there are reasons why a prompt review would have been difficult. Not only is De Magnete written in Latin, but it is also in the form of a scientific textbook. The language problem was overcome by Paul Fleury Mottelay and Silvanus P. Thompson, who translated the book into English in 1893 and 1900, respectively. The latter was published in connection with a beautiful tercentenary limited edition by the Chiswick Press that retains much of the flavor and appearance of the original. But the notion of a scientific textbook was unfamiliar when De Magnete first appeared in 1600. Certainly, scientific subjects and even geomagnetism had been written about (for example, by Petrus Peregrinus in his Epistola De Magnete, 1269), but as reports of equipment and phenomena rather than as in-depth investigations of a subject with experimental evidence and interpretation.

  17. Small angle neutron scattering measurements of magnetic cluster sizes in magnetic recorging disks

    CERN Document Server

    Toney, M

    2003-01-01

    We describe Small Angle Neutron Scattering measurements of the magnetic cluster size distributions for several longitudinal magnetic recording media. We find that the average magnetic cluster size is slightly larger than the average physical grain size, that there is a broad distribution of cluster sizes, and that the cluster size is inversely correlated to the media signal-to-noise ratio. These results show that intergranular magnetic coupling in these media is small and they provide empirical data for the cluster-size distribution that can be incorporated into models of magnetic recording.

  18. Roles of electric field on toroidal magnetic confinement

    International Nuclear Information System (INIS)

    Itoh, Kimitaka; Itoh, Sanae; Sanuki, Heiji; Fukuyama, Atsushi.

    1992-11-01

    Theoretical research on the influence of the electric field on the toroidal magnetic confinement is surveyed. The static electric field is first described. Physics pictures on the generation of the radial electric field and the influence on the confinement are shown. Neoclassical effects as well as the nonclassical processes are discussed. Emphasis is made on the connection with the improved confinement. Convective cell, i.e. the nonuniform potential on the magnetic surface is also discussed. The roles of the fluctuating electric field are then reviewed. The progress in the recent theories on the anomalous transport is addressed. Through these surveys, the impact of the experiments using the heavy ion beam probes on the modern plasma physics is illustrated. (author) 66 refs

  19. Small-scale Magnetic Flux Emergence in the Quiet Sun

    Science.gov (United States)

    Moreno-Insertis, F.; Martinez-Sykora, J.; Hansteen, V. H.; Muñoz, D.

    2018-06-01

    Small bipolar magnetic features are observed to appear in the interior of individual granules in the quiet Sun, signaling the emergence of tiny magnetic loops from the solar interior. We study the origin of those features as part of the magnetoconvection process in the top layers of the convection zone. Two quiet-Sun magnetoconvection models, calculated with the radiation-magnetohydrodynamic (MHD) Bifrost code and with domain stretching from the top layers of the convection zone to the corona, are analyzed. Using 3D visualization as well as a posteriori spectral synthesis of Stokes parameters, we detect the repeated emergence of small magnetic elements in the interior of granules, as in the observations. Additionally, we identify the formation of organized horizontal magnetic sheets covering whole granules. Our approach is twofold, calculating statistical properties of the system, like joint probability density functions (JPDFs), and pursuing individual events via visualization tools. We conclude that the small magnetic loops surfacing within individual granules in the observations may originate from sites at or near the downflows in the granular and mesogranular levels, probably in the first 1 or 1.5 Mm below the surface. We also document the creation of granule-covering magnetic sheet-like structures through the sideways expansion of a small subphotospheric magnetic concentration picked up and pulled out of the interior by a nascent granule. The sheet-like structures that we found in the models may match the recent observations of Centeno et al.

  20. Scattering Manipulation and Camouflage of Electrically Small Objects through Metasurfaces

    Science.gov (United States)

    Vellucci, S.; Monti, A.; Toscano, A.; Bilotti, F.

    2017-03-01

    In this paper, we discuss the intriguing possibility of tailoring the scattering response of an electrically small object for camouflage and illusion applications using metasurfaces. As a significant example, we focus our attention on the cylindrical geometry and derive the analytical conditions needed to camouflage the geometrical and electrical characteristics of dielectric and metallic cylinders coated with ideal metasurfaces. A closed-form expression of the camouflaging metasurface depending on the cylinder's characteristics is derived. Furthermore, the frequency behavior and the limitations of this technique are discussed with the aid of relevant examples. In order to overcome these limitations, a solution based on the use of lossy metasurfaces is proposed.

  1. Magnetic fluid droplet in a harmonic electric field

    Energy Technology Data Exchange (ETDEWEB)

    Kvasov, D., E-mail: kvasovdmitry@gmail.com [Lomonosov Moscow State University, Moscow (Russian Federation); Naletova, V. [Lomonosov Moscow State University, Moscow (Russian Federation); Beketova, E.; Dikanskii, Yu. [North-Caucasus Federal University, Stavropol (Russian Federation)

    2017-06-01

    A magnetic fluid droplet immersed in oil in an applied harmonic electric field is studied experimentally and theoretically. It is shown that deformations of the droplet observed experimentally are not described by the well-known theory. New double-layer droplet model which describes experimental data well is proposed. - Highlights: • The magnetic fluid droplet in the oil in a harmonic electric field is studied. • The paradoxical flattening effect of the droplet is observed experimentally. • For explaining this effect the model of the double-layer droplet is proposed. • Numerical and experimental data coincide qualitatively and quantitatively.

  2. Magnetoacoustic tomographic imaging of electrical impedance with magnetic induction

    Science.gov (United States)

    Xia, Rongmin; Li, Xu; He, Bin

    2007-08-01

    Magnetoacoustic tomography with magnetic induction (MAT-MI) is a recently introduced method for imaging tissue electrical impedance properties by integrating magnetic induction and ultrasound measurements. In the present study, the authors have developed a focused cylindrical scanning mode MAT-MI system and the corresponding reconstruction algorithms. Using this system, they demonstrated a three-dimensional MAT-MI imaging approach in a physical phantom, with cylindrical scanning combined with ultrasound focusing, and the ability of MAT-MI in imaging electrical conductivity properties of biological tissue.

  3. Single flexible nanofiber to simultaneously realize electricity-magnetism bifunctionality

    International Nuclear Information System (INIS)

    Yang, Ming; Sheng, Shujuan; Ma, Qianli; Lv, Nan; Yu, Wensheng; Wang, Jinxian; Dong, Xiangting; Liu, Guixia

    2016-01-01

    In order to develop new-typed multifunctional composite nanofibers, PANI/Fe 3 O 4 /PVP flexible bifunctional composite nanofibers with simultaneous electrical conduction and magnetism have been successfully fabricated via a facile electrospinning technology. Polyvinyl pyrrolidone (PVP) is used as a matrix to construct composite nanofibers containing different amounts of polyaniline (PANI) and Fe 3 O 4 nanoparticles (NPs). The bifunctional composite nanofibers simultaneously possess excellent electrical conductivity and magnetic properties. The electrical conductivity reaches up to the order of 10 -3 S·cm -1 . The electrical conductivity and saturation magnetization of the composite nanofibers can be respectively tuned by adding various amounts of PANI and Fe 3 O 4 NPs. The obtained electricity-magnetism bifunctional composite nanofibers are expected to possess many potential applications in areas such as electromagnetic interference shielding, special coating, microwave absorption, molecular electronics and future nanomechanics. More importantly, the design concept and construct technique are of universal significance to fabricate other bifunctional one-dimensional nanostructures. (author)

  4. Single flexible nanofiber to simultaneously realize electricity-magnetism bifunctionality

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ming; Sheng, Shujuan; Ma, Qianli; Lv, Nan; Yu, Wensheng; Wang, Jinxian; Dong, Xiangting; Liu, Guixia, E-mail: wenshengyu2009@sina.com, E-mail: dongxiangting888@163.com [Key Laboratory of Applied Chemistry and Nanotechnology at Universities of Jilin Province, Changchun University of Science and Technology, Changchun (China)

    2016-03-15

    In order to develop new-typed multifunctional composite nanofibers, PANI/Fe{sub 3}O{sub 4}/PVP flexible bifunctional composite nanofibers with simultaneous electrical conduction and magnetism have been successfully fabricated via a facile electrospinning technology. Polyvinyl pyrrolidone (PVP) is used as a matrix to construct composite nanofibers containing different amounts of polyaniline (PANI) and Fe{sub 3}O{sub 4} nanoparticles (NPs). The bifunctional composite nanofibers simultaneously possess excellent electrical conductivity and magnetic properties. The electrical conductivity reaches up to the order of 10{sup -3} S·cm{sup -1}. The electrical conductivity and saturation magnetization of the composite nanofibers can be respectively tuned by adding various amounts of PANI and Fe{sub 3}O{sub 4} NPs. The obtained electricity-magnetism bifunctional composite nanofibers are expected to possess many potential applications in areas such as electromagnetic interference shielding, special coating, microwave absorption, molecular electronics and future nanomechanics. More importantly, the design concept and construct technique are of universal significance to fabricate other bifunctional one-dimensional nanostructures. (author)

  5. Implementation of Permanent Magnet Motors in Electric Vehicles

    OpenAIRE

    Elvestad, Eirik

    2008-01-01

    This thesis has studied permanent magnet motors in electric vehicles (EVs) under the assumption that they are tractable due to a low weight and high compactness. The implementation has been investigated through a case study, which resulted in an EV simulation model. The model contains a maximal torque per ampere and a closed-loop field weakening controller. Abstract Faults are a special concern in permanent magnet motors. Fault sources and faulted behavior are addressed separately. The EV mo...

  6. Magnetoacoustic tomographic imaging of electrical impedance with magnetic induction

    OpenAIRE

    Xia, Rongmin; Li, Xu; He, Bin

    2007-01-01

    Magnetoacoustic tomography with magnetic induction (MAT-MI) is a recently introduced method for imaging tissue electrical impedance properties by integrating magnetic induction and ultrasound measurements. In the present study, we have developed a focused cylindrical scanning mode MAT-MI system and the corresponding reconstruction algorithms. Using this system, we demonstrated 3-dimensional MAT-MI imaging in a physical phantom, with cylindrical scanning combined with ultrasound focusing, and ...

  7. Electrical and magnetic transport properties of DyTiGe

    International Nuclear Information System (INIS)

    Dagula, W.; Tegus, O.; Li, X.W.; Zhang, L.; Brueck, E.; Boer, F.R. de; Buschow, K.H.J.

    2004-01-01

    Electrical resistivity and magnetoresistance of DyTiGe were investigated as a function of temperature and magnetic field. DyTiGe is an antiferromagnet with Neel temperature, T N , of 180 K. The electrical resistivity has an anomaly around T N . Below T N , the magnetoresistance of DyTiGe abruptly changes at a critical field. At 5 K, we observe a magnetoresistance reduction of about 20%

  8. Political determinants of electricity provision in small island developing states

    International Nuclear Information System (INIS)

    Boräng, Frida; Jagers, Sverker C.; Povitkina, Marina

    2016-01-01

    This paper approaches provision of affordable and reliable electricity in Small Island Developing States (SIDS) as a case of public good provision. It aims to contribute to our understanding of how regime type and the quality of implementing institutions within political systems affect the prerequisites for successful electrification in SIDS. More specifically, we analyse the independent and interdependent effects of level of democracy and control of corruption on per capita household electricity consumption in SIDS, using data from 34 SIDS over the period 1996–2009. The results show that although the independent effects of level of democracy and control of corruption are sensitive to model specification, these two factors do have an interdependent impact on per capita household electricity consumption: democratization has positive effects on provision of electricity to the general population only when there is a certain level of corruption control in place. The results imply a) that it is important for policy actors to acknowledge the interaction between regime type and the quality of implementing institutions, and b) when planning electrification projects in SIDS, it is necessary to have information about the social and political context in order to design the most effective projects. - Highlights: • Effects of political institutions on household electricity consumption in SIDS. • Electrification is seen as an example of public good provision. • Democracy has a positive impact on electricity consumption when corruption is low. • Electrification projects can gain from being sensitive to institutional context.

  9. Small Modular Reactors for Countries with Small to Medium Electric Grids - An Economically Sensible Solution

    International Nuclear Information System (INIS)

    Young, P.

    2012-01-01

    There has recently been a renewed interest throughout the world in small nuclear units for generating electricity and for other applications. A report by the World Nuclear Association discussing the advantages of small modular nuclear reactors (SMRs) over traditional nuclear reactor designs, states that ''modern small reactors for power generation are expected to have greater simplicity of design, economy of mass production, and reduced siting costs. Many are also designed for a high level of passive or inherent safety in the event of malfunction.'' Since the inception of nuclear power, the size of reactor units has grown from under 100 MWe to more than 1600 MWe. Today, due partly to the high capital cost of large power reactors and partly to the need to service small electricity grids, there is a move to develop smaller units. These may be built individually or as modules in a larger plant. SMRs are a good fit in markets where anticipated electricity demand is projected to increase incrementally, because SMRs could be built in series as needed. SMRs might be particularly attractive in countries that currently rely on diesel generators for producing electricity. Small reactors could make economic sense because of the high cost of diesel generation compared to the low marginal cost of producing electricity from nuclear energy. (Keeping in mind the initial investment costs and the need to establish a national regulatory program.) Some SMR designs are fabricated in a factory and then delivered to the site. This could be a solution for markets that lack the qualified engineers and skilled craft workers needed to construct large reactors on site. This paper will provide an overview of the types and attributes of SMRs in use or under development worldwide, describe the similarities and important differences between designs, discuss potential applications for SMRs, including baseload electricity generation, electricity generation for remote locations and areas with

  10. Magnetization reversal in circular vortex dots of small radius.

    Science.gov (United States)

    Goiriena-Goikoetxea, M; Guslienko, K Y; Rouco, M; Orue, I; Berganza, E; Jaafar, M; Asenjo, A; Fernández-Gubieda, M L; Fernández Barquín, L; García-Arribas, A

    2017-08-10

    We present a detailed study of the magnetic behavior of Permalloy (Ni 80 Fe 20 alloy) circular nanodots with small radii (30 nm and 70 nm) and different thicknesses (30 nm or 50 nm). Despite the small size of the dots, the measured hysteresis loops manifestly display the features of classical vortex behavior with zero remanence and lobes at high magnetic fields. This is remarkable because the size of the magnetic vortex core is comparable to the dot diameter, as revealed by magnetic force microscopy and micromagnetic simulations. The dot ground states are close to the border of the vortex stability and, depending on the dot size, the magnetization distribution combines attributes of the typical vortex, single domain states or even presents features resembling magnetic skyrmions. An analytical model of the dot magnetization reversal, accounting for the large vortex core size, is developed to explain the observed behavior, providing a rather good agreement with the experimental results. The study extends the understanding of magnetic nanodots beyond the classical vortex concept (where the vortex core spins have a negligible influence on the magnetic behavior) and can therefore be useful for improving emerging spintronic applications, such as spin-torque nano-oscillators. It also delimits the feasibility of producing a well-defined vortex configuration in sub-100 nm dots, enabling the intracellular magneto-mechanical actuation for biomedical applications.

  11. Electric and magnetic fields in medicine and biology

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    Papers Include: The effects of low frequency (50 Hz) magnetic fields on neuro-chemical transmission in vitro; Morphological changes in E Coli subjected to DC electrical fields; An investigation of some claimed biological effects of electromagnetic fields; Electrical phenomena and bone healing - a comparison of contemporary techniques; Clinical evaluations of a portable module emitting pulsed RF energy; The design, construction and performance of a magnetic nerve stimulator; The principle of electric field tomography and its application to selective read-out of information from peripheral nerves; Applied potential tomography - clinical applications; Impendance imaging using a linear electrode array; Mathematics as an aid to experiment: human body currents induced by power frequency electric fields; Effects of electric field near 750KV transmission line and protection against their harmful consequences; Leukemia and electromagnetic fields: a case-control study; Overhead power lines and childhood cancer; Magnetic measurement of nerve action currents - a new intraoperative recording technique; The potential use of electron spin resonance or impedance measurement to image neuronal electrical activity in the human brain

  12. Electrical detection of magnetization reversal without auxiliary magnets

    Czech Academy of Sciences Publication Activity Database

    Olejník, Kamil; Novák, Vít; Wunderlich, Joerg; Jungwirth, Tomáš

    2015-01-01

    Roč. 91, č. 18 (2015), , "180402-1"-"180402-5" ISSN 1098-0121 R&D Projects: GA MŠk(CZ) LM2011026; GA ČR GB14-37427G EU Projects: European Commission(XE) 268066 - 0MSPIN Institutional support: RVO:68378271 Keywords : spin Hall effect * magnetoresistance Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.736, year: 2014

  13. Electric-field control of magnetic domain-wall velocity in ultrathin cobalt with perpendicular magnetization.

    Science.gov (United States)

    Chiba, D; Kawaguchi, M; Fukami, S; Ishiwata, N; Shimamura, K; Kobayashi, K; Ono, T

    2012-06-06

    Controlling the displacement of a magnetic domain wall is potentially useful for information processing in magnetic non-volatile memories and logic devices. A magnetic domain wall can be moved by applying an external magnetic field and/or electric current, and its velocity depends on their magnitudes. Here we show that the applying an electric field can change the velocity of a magnetic domain wall significantly. A field-effect device, consisting of a top-gate electrode, a dielectric insulator layer, and a wire-shaped ferromagnetic Co/Pt thin layer with perpendicular anisotropy, was used to observe it in a finite magnetic field. We found that the application of the electric fields in the range of ± 2-3 MV cm(-1) can change the magnetic domain wall velocity in its creep regime (10(6)-10(3) m s(-1)) by more than an order of magnitude. This significant change is due to electrical modulation of the energy barrier for the magnetic domain wall motion.

  14. Approximating transcranial magnetic stimulation with electric stimulation in mouse: a simulation study.

    Science.gov (United States)

    Barnes, Walter L; Lee, Won Hee; Peterchev, Angel V

    2014-01-01

    Rodent models are valuable for preclinical examination of novel therapeutic techniques, including transcranial magnetic stimulation (TMS). However, comparison of TMS effects in rodents and humans is confounded by inaccurate scaling of the spatial extent of the induced electric field in rodents. The electric field is substantially less focal in rodent models of TMS due to the technical restrictions of making very small coils that can handle the currents required for TMS. We examine the electric field distributions generated by various electrode configurations of electric stimulation in an inhomogeneous high-resolution finite element mouse model, and show that the electric field distributions produced by human TMS can be approximated by electric stimulation in mouse. Based on these results and the limits of magnetic stimulation in mice, we argue that the most practical and accurate way to model focal TMS in mice is electric stimulation through either cortical surface electrodes or electrodes implanted halfway through the mouse cranium. This approach could allow much more accurate approximation of the human TMS electric field focality and strength than that offered by TMS in mouse, enabling, for example, focal targeting of specific cortical regions, which is common in human TMS paradigms.

  15. Electrical resistivity of UBe13 in high magnetic fields

    International Nuclear Information System (INIS)

    Schmiedeshoff, G.M.; Lacerda, A.; Fisk, Z.; Smith, J.L.

    1996-01-01

    We have measured the temperature dependent electrical resistivity of single and polycrystal samples of UBe 13 in high magnetic fields. Two maxima in the resistivity are observed at T M1 and T M2 . T M1 , the temperature of the colder maximum, increases quadratically with magnetic field H, a field dependence previously observed under hydrostatic pressure. The high temperature maximum at T M2 emerges in fields above about 4 T and increases linearly with H, a behavior which may be due to a sharpening of the crystal field levels associated with a depression of the Kondo effect by high magnetic fields. copyright 1996 The American Physical Society

  16. Method for Measuring Small Nonlinearities of Electric Characteristics

    DEFF Research Database (Denmark)

    Guldbrandsen, Tom; Meyer, Niels I; Schjær-Jacobsen, Jørgen

    1965-01-01

    A method is described for measuring very small deviations from linearity in electric characteristics. The measurement is based on the harmonics generated by the nonlinear element when subjected to a sine wave signal. A special bridge circuit is used to balance out the undesired harmonics...... of the signal generator together with the first harmonic frequency. The set-up measures the small-signal value and the first and second derivative with respect to voltage. The detailed circuits are given for measuring nonlinearities in Ohmic and capacitive components. In the Ohmic case, a sensitivity...

  17. Electric and magnetic properties of hot gluons

    International Nuclear Information System (INIS)

    Hansson, T.H.; Zahed, I.

    1987-01-01

    The dielectric constant ε and magnetic permeability μ for gluon plasma are calculated from the one-loop gauge-invariant effective action. The real parts are gauge-fixing independent and agree with earlier work. The imaginary part of μ/sup -1/ is zero in any covariant background-field gauge, while the imaginary part of ε is gauge-fixing dependent and negative definite. This result indicates that there is no consistent perturbative description of gluonic plasmons on scale ≥(g 2 T)/sup -1/

  18. Size and importance of small electrical end uses in households

    Energy Technology Data Exchange (ETDEWEB)

    Broderick, J R; Zogg, R A; Alberino, D L

    1998-07-01

    Miscellaneous end uses (an energy-consumption category in the residential sector) has recently emerged with more importance than ever before. Miscellaneous end uses are a collection of numerous end uses (often unrelated in technology or market characteristics) that individually are small consumers but when grouped together can become notable in size. The Annual Energy Outlook 1998, published by the Energy Information Administration (EIA), suggests that about 32% of residential electricity use in 1996 is attributable to miscellaneous end uses (21% from the Other Uses category and 11% from other miscellaneous categories). The EIA predicts this consumption will grow to about 47% of residential electricity use by 2010. Other studies have shown substantial consumption in this category, and forecast substantial future growth as well. However, it is not clear that the current accounting structure of the miscellaneous category is the most appropriate one, nor that the forecast growth in consumption will materialize. A bottom-up study on a collection of miscellaneous electric end uses was performed to better understand this complex, ill-defined category. Initial results show that many end uses can be categorized more appropriately, such as furnace fans, which belong in Space Heating. A recommended categorization reduces the Other Uses category from 21% to 12% of electric consumption estimated in 1996. Thus, the consumption from miscellaneous end uses is not nearly as large as thought. Furthermore, the growth rate associated with small end uses is projected to be lower relative to projections from other sources.

  19. Electric-field-induced superconductivity detected by magnetization measurements of an electric-double-layer capacitor

    International Nuclear Information System (INIS)

    Kasahara, Yuichi; Takeuchi, Yuki; Ye, Jianting; Yuan, Hongtao; Shimotani, Hidekazu; Iwasa, Yoshihiro; Nishimura, Takahiro; Sato, Tatsuya

    2010-01-01

    We report evidence for superconductivity induced by the application of strong electric fields onto the surface of a band insulator, ZrNCl, provided by the observation of a shielding diamagnetic signal. We introduced an electric-double-layer capacitor configuration and in situ magnetization measurements at low temperatures as a method to detect the novel electric-field-induced superconducting state. The results showed excellent agreement with a previous report using a transistor configuration, demonstrating that the present technique is a novel method for investigating the nonequilibrium phase induced by electric fields. (author)

  20. Electrically Controllable Spontaneous Magnetism in Nanoscale Mixed Phase Multiferroics

    Energy Technology Data Exchange (ETDEWEB)

    He, Q.; Chu, Y. H.; Heron, J. T.; Yang, S. Y.; Wang, C. H.; Kuo, C. Y.; Lin, H. J.; Yu, P.; Liang, C. W.; Zeches, R. J.; Chen, C. T.; Arenholz, E.; Scholl, A.; Ramesh, R.

    2010-08-02

    The emergence of enhanced spontaneous magnetic moments in self-assembled, epitaxial nanostructures of tetragonal (T-phase) and rhombohedral phases (R-phase) of the multiferroic BiFeO{sub 3} system is demonstrated. X-ray magnetic circular dichroism based photoemission electron microscopy (PEEM) was applied to investigate the local nature of this magnetism. We find that the spontaneous magnetization of the R-phase is significantly enhanced above the canted antiferromagnetic moment in the bulk phase, as a consequence of a piezomagnetic coupling to the adjacent T-phase and the epitaxial constraint. Reversible electric field control and manipulation of this magnetic moment at room temperature is shown using a combination of piezoresponse force microscopy and PEEM studies.

  1. Assessing students' conceptual knowledge of electricity and magnetism

    Science.gov (United States)

    McColgan, Michele W.; Finn, Rose A.; Broder, Darren L.; Hassel, George E.

    2017-12-01

    We present the Electricity and Magnetism Conceptual Assessment (EMCA), a new assessment aligned with second-semester introductory physics courses. Topics covered include electrostatics, electric fields, circuits, magnetism, and induction. We have two motives for writing a new assessment. First, we find other assessments such as the Brief Electricity and Magnetism Assessment and the Conceptual Survey on Electricity and Magnetism not well aligned with the topics and content depth of our courses. We want to test introductory physics content at a level appropriate for our students. Second, we want the assessment to yield scores and gains comparable to the widely used Force Concept Inventory (FCI). After five testing and revision cycles, the assessment was finalized in early 2015 and is available online. We present performance results for a cohort of 225 students at Siena College who were enrolled in our algebra- and calculus-based physics courses during the spring 2015 and 2016 semesters. We provide pretest, post-test, and gain analyses, as well as individual question and whole test statistics to quantify difficulty and reliability. In addition, we compare EMCA and FCI scores and gains, and we find that students' FCI scores are strongly correlated with their performance on the EMCA. Finally, the assessment was piloted in an algebra-based physics course at George Washington University (GWU). We present performance results for a cohort of 130 GWU students and we find that their EMCA scores are comparable to the scores of students in our calculus-based physics course.

  2. Sensing electric and magnetic fields with Bose-Einstein condensates

    DEFF Research Database (Denmark)

    Wildermuth, Stefan; Hofferberth, S.; Lesanovsky, Igor

    2006-01-01

    We experimentally demonstrate that one-dimensional Bose-Einstein condensates brought close to microfabricated wires on an atom chip are a very sensitive sensor for magnetic and electric fields reaching a sensitivity to potential variations of ∼ 10-14 eV at 3 μm spatial resolution. We measure a two...

  3. Electric charge quantization and the muon anomalous magnetic moment

    International Nuclear Information System (INIS)

    Pires, C.A.S. de; Rodrigues da Silva, P.S.

    2002-01-01

    We investigate some proposals to solve the electric charge quantization puzzle that simultaneously explain the recent measured deviation on the muon anomalous magnetic moment. For this we assess extensions of the electro-weak standard model spanning modifications on the scalar sector only. It is interesting to verify that one can have modest extensions which easily account for the solution for both problems

  4. Electric and magnetic fields at extremely low frequencies

    International Nuclear Information System (INIS)

    Anderson, L.E.; Kaune, W.T.

    1989-01-01

    Whole-body exposure to extremely low frequency (ELF, 30-300 Hz) electric fields may involve effects related to stimulation of the sensory apparatus at the body surface (hair vibration, possible direct neural stimulation) and effects within the body caused by the flow of current. Magnetic fields may interact predominantly by the induction of internal current flow. Biological effects observed in a living organism may depend on the electric fields induced inside the body, possibly on the magnetic fields penetrating into the body, and on the fields acting at the surface of the body. Areas in which effects have been observed often appear to be associated with the nervous system, including altered neuronal excitability and neurochemical changes, altered hormone levels, changes in behavioural responses, and changes in biological rhythms. No studies unequivocably demonstrate deleterious effects of ELF electric or magnetic field exposure on mammalian reproduction and development, but several suggest such effects. Exposure to ELF electric and magnetic fields does produce biological effects. However, except for fields strong enough to induce current densities above the threshold for the stimulation of nerve tissues, there is no consensus as to whether these effects constitute a hazard to human health. Human data from epidemiological studies, including reported effects on cancer promotion, congenital malformations, reproductive performance and general health, though somewhat suggestive of adverse health effects, are not conclusive. 274 refs, 13 figs, 6 tabs

  5. Anomalous Magnetic and Electric Dipole Moments of the $\\tau$

    CERN Document Server

    Taylor, L

    1998-01-01

    This paper reviews the theoretical predictions for and the experimental measurements of the anomalous magnetic and electric dipole moments of the tau lepton. In particular, recent analyses of the e/sup +/e/sup -/ to tau /sup +/ tau /sup -/ gamma process from the L3 and OPAL collaborations are described. The most precise results, from L3, for the anomalous magnetic and electric dipole moments respectively are: a/sub tau /=0.004+or-0.027+or-0.023 and d /sub tau /=(0.0+or-1.5+or-1.3)*10/sup -16/ e.cm. (22 refs). This paper reviews the theoretical predictions for and the experimental measurements of the anomalous magnetic and electric dipole moments of the tau lepton. In particular, recent analyses of the $\\eettg$ process from the L3 and OPAL collaborations are described. The most precise results, from L3, for the anomalous magnetic and electric dipole moments respectively are: $\\atau = 0.004 10^{-16}{e{\\cdot}\\mathrm{cm}}$.

  6. Calculation of the Magnetic Fields of the Electric Power Line

    Directory of Open Access Journals (Sweden)

    Patsiuk V.

    2016-12-01

    Full Text Available The task of calculation of per unit length parameters of multi-conductor electrical overhead transmission lines has been treated in the paper. The calculation of distribution of electric and magnetic fields has been performed by means of the finite volume method for entire span of the line. The theoretical justification of the method for calculation the parameters of electromagnetic field taking into account the change of the vector of magnetic potential along the line has been given. The problems of electrostatic and magnetostatic for a single electric conductor and unlimited long conductor with current have been solved. For the inner and total inductivities of a single conductor under the current have been obtained relationships and drawn dependences. Dependence between the speeds of light and of electromagnetic wave’s propagation has been presented. Based on the characteristics of distribution of electric and magnetic fields of multi-conductor lines has been provided the method of calculation of the matrix of own and mutual capacitances and inductivities the calculated values of per unit length parameters of compact 110 kV electric line which is in concordance with one of basic physical constant – the speed of light.

  7. Low frequency electric and magnetic fields - the topic of cancer

    International Nuclear Information System (INIS)

    Thommesen, G.

    1988-01-01

    A review is made of the literature about the biological effects of low frequency electric and magnetic fields. It is still an unsettled question whether extremely low frequency magnetic fields may increase the incidence of cancer. Experimental data arise mainly from exposure to field strengths or frequencies seldom or never encountered by people. The results give no clear explanation to the increase in cancer incidence reported in epidemiological works. The spectre of possible mechanisms imply that no simple dose/effect relationship should be expected, as conflicting mechanisms may dominate at different exposure levels. There is therefore no basis at present for giving numerical value to cancer risk from exposure to low frequency electric or magnetic fields

  8. On the radiation of electric, magnetic and toroidal dipoles

    International Nuclear Information System (INIS)

    Afanas'ev, G.N.; Stepanovskij, Yu.P.

    2002-01-01

    We consider the radiation of electric, magnetic and toroidal dipoles uniformly moving in unbounded medium (this corresponds to the Tamm-Frank problem). The densities of these dipoles are obtained from the corresponding charge-current densities in an infinitesimal limit. The behaviour of radiation intensities in the neighbourhood of the Cherenkov threshold β = 1/n is investigated. The frequency and velocity regions are defined where radiation intensities are maximal. The comparison with previous attempts is given. We consider also the radiation of electric, magnetic and toroidal dipoles uniformly moving in medium, in a finite space interval (this corresponds to the Tamm problem). The properties of radiation arising from the precession of a magnetic dipole are studied

  9. On the Radiation of Electric, Magnetic and Toroidal Dipoles

    CERN Document Server

    Afanasiev, G N

    2002-01-01

    We consider the radiation of electric, magnetic and toroidal dipoles uniformly moving in unbounded medium (this corresponds to the Tamm-Frank problem). The densities of these dipoles are obtained from the corresponding charge-current densities in an infinitesimal limit. The behaviour of radiation intensities in the neighbourhood of the Cherenkov threshold beta=1/n is investigated. The frequency and velocity regions are defined where radiation intensities are maximal. The comparison with previous attempts is given. We consider also the radiation of electric, magnetic and toroidal dipoles uniformly moving in medium, in a finite space interval (this corresponds to the Tamm problem). The properties of radiation arising from the precession of a magnetic dipole are studied.

  10. Electric and magnetic field reduction by alternative transmission line options

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, J.R. (Power Technologies, Inc., Schenectady, NY (United States)); Dale, S.J. (Oak Ridge National Lab., TN (United States)); Klein, K.W. (Energetics, Inc., Columbia, MD (United States))

    1991-01-01

    Ground level electric, and more recently magnetic, fields from overhead power transmission lines are increasingly important considerations in right of way specification, with states setting or planning to set edge of right of way limits. Research has been conducted in high phase order power transmission wherein six of twelve phases are used to transmit power in less physical space and with reduced electrical environmental effects than conventional designs. The first magnetic field testing, as reported in this paper, has verified predictive methods for determination of magnetic fields from high phase order lines. Based on these analytical methods, field profiles have been determined for lines of different phase order of comparable power capacity. Potential advantages of high phase order as a means of field mitigation are discussed. 10 refs., 12 figs., 3 tabs.

  11. Ionospheric midlatitude electric current density inferred from multiple magnetic satellites

    DEFF Research Database (Denmark)

    Shore, R. M.; Whaler, K. A.; Macmillan, S.

    2013-01-01

    A method for inferring zonal electric current density in the mid-to-low latitude F region ionosphere is presented. We describe a method of using near-simultaneous overflights of the Ørsted and CHAMP satellites to define a closed circuit for an application of Ampère's integral law to magnetic data...... for estimates of main and crustal magnetic fields. Current density in the range ±0.1 μA/m2 is resolved, with the distribution of electric current largely matching known features such as the Appleton anomaly. The currents appear unmodulated at times of either high-negative Dst or high F10.7, which has...... implications for any future efforts to model their effects. We resolve persistent current intensifications between geomagnetic latitudes of 30 and 50° in the postmidnight, predawn sector, a region typically thought to be relatively free of electric currents. The cause of these unexpected intensifications...

  12. EVALUATING EXTREMELY LOW FREQUENCY MAGNETIC FIELDS IN THE REAR SEATS OF THE ELECTRIC VEHICLES.

    Science.gov (United States)

    Lin, Jun; Lu, Meng; Wu, Tong; Yang, Lei; Wu, Tongning

    2018-03-23

    In the electric vehicles (EVs), children can sit on a safety seat installed in the rear seats. Owing to their smaller physical dimensions, their heads, generally, are closer to the underfloor electrical systems where the magnetic field (MF) exposure is the greatest. In this study, the magnetic flux density (B) was measured in the rear seats of 10 different EVs, for different driving sessions. We used the measurement results from different heights corresponding to the locations of the heads of an adult and an infant to calculate the induced electric field (E-field) strength using anatomical human models. The results revealed that measured B fields in the rear seats were far below the reference levels by the International Commission on Non-Ionizing Radiation Protection. Although small children may be exposed to higher MF strength, induced E-field strengths were much lower than that of adults due to their particular physical dimensions.

  13. ATLAS magnet common cryogenic, vacuum, electrical and control systems

    CERN Document Server

    Miele, P; Delruelle, N; Geich-Gimbel, C; Haug, F; Olesen, G; Pengo, R; Sbrissa, E; Tyrvainen, H; ten Kate, H H J

    2004-01-01

    The superconducting Magnet System for the ATLAS detector at the LHC at CERN comprises a Barrel Toroid, two End Cap Toroids and a Central Solenoid with overall dimensions of 20 m diameter by 26 m length and a stored energy of 1.6 GJ. Common proximity cryogenic and electrical systems for the toroids are implemented. The Cryogenic System provides the cooling power for the 3 toroid magnets considered as a single cold mass (600 tons) and for the CS. The 21 kA toroid and the 8 kA solenoid electrical circuits comprise both a switch-mode power supply, two circuit breakers, water cooled bus bars, He cooled current leads and the diode resistor ramp-down unit. The Vacuum System consists of a group of primary rotary pumps and sets of high vacuum diffusion pumps connected to each individual cryostat. The Magnet Safety System guarantees the magnet protection and human safety through slow and fast dump treatment. The Magnet Control System ensures control, regulation and monitoring of the operation of the magnets. The update...

  14. Current-voltage characteristics of a superconducting slab under a superimposed small AC magnetic field

    International Nuclear Information System (INIS)

    Matsushita, Teruo; Yamafuji, Kaoru; Sakamoto, Nobuyoshi.

    1977-01-01

    In case of applying superconductors to electric machinery or high intensity field magnets for fusion reactors, the superconductors are generally expected to be sensible to small field fluctuation besides DC magnetic field. The behavior of superconductors in DC magnetic field superimposed with small AC magnetic field has been investigated often experimentally, and the result has been obtained that the critical current at which DC flow voltage begins to appear extremely decreased or disappeared. Some theoretical investigations have been carried out on this phenomenon so far, however, their application has been limited to the region where frequency is sufficiently low or which is close to the critical magnetic field. Purpose of this report is to deal with the phenomenon in more unified way by analyzing the behavior of magnetic flux lines in a superconductor under a superimposed small AC field using the criticalstate model including viscous force. In order to solve the fundamental equation in this report, first the solution has been obtained in the quasi-static state neglecting viscous force, then about the cases that current density J is not more than Jc and J is larger than Jc, concerning the deviation from the quasi-static limit by employing successive approximation. Current-voltage characteristics have been determined by utilizing the above results. This method seems to be most promising at present except the case of extremely high frequency. (Wakatsuki, Y.)

  15. Cost of electricity from small scale co-generation of electricity and heat

    Energy Technology Data Exchange (ETDEWEB)

    Kjellstroem, Bjoern

    2012-07-15

    There is an increasing interest in Sweden for using also small heat loads for cogeneration of electricity and heat. Increased use of small CHP-plants with heat supply capacities from a few 100 kW(h) up to 10 MW(h) cannot change the structure of the electricity supply system significantly, but could give an important contribution of 2 - 6 TWh(e) annually. The objective of this study was to clarify under what conditions electricity can be generated in small wood fired CHP-plants in Sweden at costs that can compete with those for plants using fossil fuels or nuclear energy. The capacity range studied was 2 - 10 MW(h). The results should facilitate decisions about the meaningfulness of considering CHP as an option when new heat supply systems for small communities or sawmills are planned. At the price for green certificates in Sweden, 250 - 300 SEK/MWh(e), generation costs in small wood fired CHP-plants should be below about 775 SEK/MWh(e) to compete with new nuclear power plants and below about 925 SEK/MWh(e) to compete with generation using fossil fuels.

  16. Advanced Electric and Magnetic Material Models for FDTD Electromagnetic Codes

    CERN Document Server

    Poole, Brian R; Nelson, Scott D

    2005-01-01

    The modeling of dielectric and magnetic materials in the time domain is required for pulse power applications, pulsed induction accelerators, and advanced transmission lines. For example, most induction accelerator modules require the use of magnetic materials to provide adequate Volt-sec during the acceleration pulse. These models require hysteresis and saturation to simulate the saturation wavefront in a multipulse environment. In high voltage transmission line applications such as shock or soliton lines the dielectric is operating in a highly nonlinear regime, which requires nonlinear models. Simple 1-D models are developed for fast parameterization of transmission line structures. In the case of nonlinear dielectrics, a simple analytic model describing the permittivity in terms of electric field is used in a 3-D finite difference time domain code (FDTD). In the case of magnetic materials, both rate independent and rate dependent Hodgdon magnetic material models have been implemented into 3-D FDTD codes an...

  17. ADVANCED ELECTRIC AND MAGNETIC MATERIAL MODELS FOR FDTD ELECTROMAGNETIC CODES

    Energy Technology Data Exchange (ETDEWEB)

    Poole, B R; Nelson, S D; Langdon, S

    2005-05-05

    The modeling of dielectric and magnetic materials in the time domain is required for pulse power applications, pulsed induction accelerators, and advanced transmission lines. For example, most induction accelerator modules require the use of magnetic materials to provide adequate Volt-sec during the acceleration pulse. These models require hysteresis and saturation to simulate the saturation wavefront in a multipulse environment. In high voltage transmission line applications such as shock or soliton lines the dielectric is operating in a highly nonlinear regime, which require nonlinear models. Simple 1-D models are developed for fast parameterization of transmission line structures. In the case of nonlinear dielectrics, a simple analytic model describing the permittivity in terms of electric field is used in a 3-D finite difference time domain code (FDTD). In the case of magnetic materials, both rate independent and rate dependent Hodgdon magnetic material models have been implemented into 3-D FDTD codes and 1-D codes.

  18. ADVANCED ELECTRIC AND MAGNETIC MATERIAL MODELS FOR FDTD ELECTROMAGNETIC CODES

    International Nuclear Information System (INIS)

    Poole, B R; Nelson, S D; Langdon, S

    2005-01-01

    The modeling of dielectric and magnetic materials in the time domain is required for pulse power applications, pulsed induction accelerators, and advanced transmission lines. For example, most induction accelerator modules require the use of magnetic materials to provide adequate Volt-sec during the acceleration pulse. These models require hysteresis and saturation to simulate the saturation wavefront in a multipulse environment. In high voltage transmission line applications such as shock or soliton lines the dielectric is operating in a highly nonlinear regime, which require nonlinear models. Simple 1-D models are developed for fast parameterization of transmission line structures. In the case of nonlinear dielectrics, a simple analytic model describing the permittivity in terms of electric field is used in a 3-D finite difference time domain code (FDTD). In the case of magnetic materials, both rate independent and rate dependent Hodgdon magnetic material models have been implemented into 3-D FDTD codes and 1-D codes

  19. Electrically tuned magnetic order and magnetoresistance in a topological insulator.

    Science.gov (United States)

    Zhang, Zuocheng; Feng, Xiao; Guo, Minghua; Li, Kang; Zhang, Jinsong; Ou, Yunbo; Feng, Yang; Wang, Lili; Chen, Xi; He, Ke; Ma, Xucun; Xue, Qikun; Wang, Yayu

    2014-09-15

    The interplay between topological protection and broken time reversal symmetry in topological insulators may lead to highly unconventional magnetoresistance behaviour that can find unique applications in magnetic sensing and data storage. However, the magnetoresistance of topological insulators with spontaneously broken time reversal symmetry is still poorly understood. In this work, we investigate the transport properties of a ferromagnetic topological insulator thin film fabricated into a field effect transistor device. We observe a complex evolution of gate-tuned magnetoresistance, which is positive when the Fermi level lies close to the Dirac point but becomes negative at higher energies. This trend is opposite to that expected from the Berry phase picture, but is intimately correlated with the gate-tuned magnetic order. The underlying physics is the competition between the topology-induced weak antilocalization and magnetism-induced negative magnetoresistance. The simultaneous electrical control of magnetic order and magnetoresistance facilitates future topological insulator based spintronic devices.

  20. Tool for the control management of electric and magnetic fields of electrical companies

    International Nuclear Information System (INIS)

    Arnera, Patricia; Barbieri, Beatriz

    2008-01-01

    The use of electricity involves a wide range of activities that, because of its diversity, characteristics and relative importance causes different environmental impacts during the extraction, processing, transport and consuming activities. It is the role of the government to elaborate the rules for the incorporation of environmental aspects in the different segments of the market for different electrical energy sources and in all the stages of the process, from the initial evaluation to the construction and exploitation phases. Among the environmental key aspects to considerate, are the electric and magnetic fields, in which society has taken special interest as they are believed to be involved in health hazard. The faculties of the regulatory authority are dictate regulations and technique procedures to be fulfilled by the agents, and check their compliance. In the course of time since the mentioned obligations, the authority has gathered information regarding electric and magnetic fields that includes those planned in the Companies Environmental Planning and those obtained ad-hoc in the role of controller. In order to systematize this information, a data base has been designed considering different types of electric installations, the company which they belong to, equipment used in the measurements, representative layouts with measure points and profiles of the electric and magnetic fields that were obtained. (author)

  1. Tool for the control management of electric and magnetic fields of electrical companies

    Energy Technology Data Exchange (ETDEWEB)

    Arnera, Patricia; Barbieri, Beatriz [La Plata Univ. Nacional (Argentina). Facultad de Ingenieria, Instituto de Investigaciones Tecnologicas para Redes y Equipos; Turco, Joaquin; Messina, Juan; Postiglioni, Osvaldo [Ente Nacional Regulador de la Electricidad, Buenos Aires (Argentina)

    2008-07-01

    The use of electricity involves a wide range of activities that, because of its diversity, characteristics and relative importance causes different environmental impacts during the extraction, processing, transport and consuming activities. It is the role of the government to elaborate the rules for the incorporation of environmental aspects in the different segments of the market for different electrical energy sources and in all the stages of the process, from the initial evaluation to the construction and exploitation phases. Among the environmental key aspects to considerate, are the electric and magnetic fields, in which society has taken special interest as they are believed to be involved in health hazard. The faculties of the regulatory authority are dictate regulations and technique procedures to be fulfilled by the agents, and check their compliance. In the course of time since the mentioned obligations, the authority has gathered information regarding electric and magnetic fields that includes those planned in the Companies Environmental Planning and those obtained ad-hoc in the role of controller. In order to systematize this information, a data base has been designed considering different types of electric installations, the company which they belong to, equipment used in the measurements, representative layouts with measure points and profiles of the electric and magnetic fields that were obtained. (author)

  2. A corotation electric field model of the Earth derived from Swarm satellite magnetic field measurements

    Science.gov (United States)

    Maus, Stefan

    2017-08-01

    Rotation of the Earth in its own geomagnetic field sets up a primary corotation electric field, compensated by a secondary electric field of induced electrical charges. For the geomagnetic field measured by the Swarm constellation of satellites, a derivation of the global corotation electric field inside and outside of the corotation region is provided here, in both inertial and corotating reference frames. The Earth is assumed an electrical conductor, the lower atmosphere an insulator, followed by the corotating ionospheric E region again as a conductor. Outside of the Earth's core, the induced charge is immediately accessible from the spherical harmonic Gauss coefficients of the geomagnetic field. The charge density is positive at high northern and southern latitudes, negative at midlatitudes, and increases strongly toward the Earth's center. Small vertical electric fields of about 0.3 mV/m in the insulating atmospheric gap are caused by the corotation charges located in the ionosphere above and the Earth below. The corotation charges also flow outward into the region of closed magnetic field lines, forcing the plasmasphere to corotate. The electric field of the corotation charges further extends outside of the corotating regions, contributing radial outward electric fields of about 10 mV/m in the northern and southern polar caps. Depending on how the magnetosphere responds to these fields, the Earth may carry a net electric charge.

  3. Composite Materials with Magnetically Aligned Carbon Nanoparticles Having Enhanced Electrical Properties and Methods of Preparation

    Science.gov (United States)

    Hong, Haiping (Inventor); Peterson, G.P. (Bud) (Inventor); Salem, David R. (Inventor)

    2016-01-01

    Magnetically aligned carbon nanoparticle composites have enhanced electrical properties. The composites comprise carbon nanoparticles, a host material, magnetically sensitive nanoparticles and a surfactant. In addition to enhanced electrical properties, the composites can have enhanced mechanical and thermal properties.

  4. Torque vectoring for improving stability of small electric vehicles

    Science.gov (United States)

    Grzegożek, W.; Weigel-Milleret, K.

    2016-09-01

    The electric vehicles solutions based on the individually controlled electric motors propel a single wheel allow to improve the dynamic properties of the vehicle by varying the distribution of the driving torque. Most of the literature refer to the vehicles with a track typical for passenger cars. This paper examines whether the narrow vehicle (with a very small track) torque vectoring bring a noticeable change of the understeer characteristics and whether torque vectoring is possible to use in securing a narrow vehicle from roll over (roll mitigation). The paper contains road tests of the steering characteristics (steady state understeer characteristic quasi-static acceleration with a fixed steering wheel (SH = const) and on the constant radius track (R = const)) of the narrow vehicle. The vehicle understeer characteristic as a function of a power distribution is presented.

  5. Electric Conductivity and Dielectric-Breakdown Behavior for Polyurethane Magnetic Elastomers.

    Science.gov (United States)

    Sasaki, Shuhei; Tsujiei, Yuri; Kawai, Mika; Mitsumata, Tetsu

    2017-02-23

    The electric-voltage dependence of the electric conductivity for cross-linked and un-cross-linked magnetic elastomers was measured at various magnetic fields, and the effect of cross-linking on the electric conductivity and the dielectric-breakdown behavior was investigated. The electric conductivity for un-cross-linked elastomers at low voltages was independent of magnetic fields and the volume fraction of magnetic particles, indicating the electric conduction in the polyurethane matrix. At high voltages, the electric conductivity increased with the magnetic field, showing the electric conduction via chains of magnetic particles. On the other hand, the electric conductivity at low voltages for cross-linked elastomers with volume fractions below 0.06 was independent of the magnetic field, suggesting the electric conduction in the polyurethane matrix. At volume fractions above 0.14, the electric conductivity increased with the magnetic field, suggesting the electric conduction via chains of magnetic particles. At high voltages, the electric conductivity for cross-linked elastomers with a volume fraction of 0.02 was independent of the magnetic field, indicating the electric conduction through the polyurethane matrix. At volume fractions above 0.06, the electric conductivity suddenly increased at a critical voltage, exhibiting the dielectric breakdown at the bound layer of magnetic particles and/or the discontinuous part between chains.

  6. Effect of metallurgical factors on the bulk magnetic properties of non-oriented electrical steels

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Pampa, E-mail: pampaghosh@gmail.com [Department of Mining and Materials Engineering, McGill University, 3610 University Street, Montreal, Que., Canada H3A 0C5 (Canada); Chromik, Richard R., E-mail: richard.chromik@mcgill.ca [Department of Mining and Materials Engineering, McGill University, 3610 University Street, Montreal, Que., Canada H3A 0C5 (Canada); Knight, Andrew M. [Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alta., Canada T6G 2V4 (Canada); Wakade, Shekhar G. [GM Powertrain, General Motors Company, 823 Joslyn Avenue, Building B, 4AJ35, Pontiac, MI 48340-2920 (United States)

    2014-04-01

    Non-oriented electrical steel (NOES) is one of the most common material used in electrical motors. Core loss and permeability are the most important properties that the motor manufacturers look for. Both these properties are structure sensitive and depend on several metallurgical factors; such as chemistry, grain size, crystallographic texture, cleanliness and stress states in non-oriented electrical steels. It has been observed in this course of the study that the grain size and Si content of NOES are the primary controlling factors to core loss, especially at higher frequencies. On the contrary, crystallographic texture plays an important role at lower frequencies. At higher frequency, core loss increases with increasing grain size and decreasing Si content of the steels. Small difference in grain size (∼50 μm) at lower frequency range has little influence on the magnetic properties but has significant adverse effect as frequency reaches high enough. - Highlights: • Magnetic properties of a set of electrical steels were measured. • Crystallographic texture, chemistry and grain size were studied for their effects on core loss and permeability. • Structure–magnetic property relationships were identified for the electrical steels.

  7. Effect of metallic and hyperbolic metamaterial surface on electric and magnetic dipole emission

    DEFF Research Database (Denmark)

    Ni, Xingjie; Naik, Gururaj V.; Kildishev, Alexander V.

    2010-01-01

    Spontaneous emission patterns of electric and magnetic dipoles on different material surfaces were studied numerically and experimentally. The results show the modified behavior of electric and magnetic dipoles on metallic and HMM surfaces.......Spontaneous emission patterns of electric and magnetic dipoles on different material surfaces were studied numerically and experimentally. The results show the modified behavior of electric and magnetic dipoles on metallic and HMM surfaces....

  8. Investigation of transient electrical, magnetic, and mechanical phenomena in large superconducting magnet coils

    International Nuclear Information System (INIS)

    Sihler, C.

    1996-07-01

    The progress in the field of technology for superconducting magnets led to the necessity of transferring existing calculation methods from electrical power engineering, modifying these tools to satisfy the boundary conditions for superconducting magnets, and also developing new calculation methods for special purposes. In this work suitable calculation methods are elaborated. Their validity and applicability is demonstrated in employing these scientific engineering tools to actual developments of the Forschungszentrum Karlsruhe. In detail this work deals with: 1. calculating eddy current and force densities in the conducting environment of a superconducting magnet or magnet system. 2. the effects of eddy current forces in experimental engineering; 3. transient effects of electrical surges acting on new coil designs; and 4. the electrical and magnetic properties of superconducting cables. Especially, the magnetic properties can lead to an inhomogeneous current distribution in the cable and, thus, to a considerable reduction of the current carrying capacity of the whole magnet. These investigations demonstrate that a detailed analysis of electrodynamic phenomena is indispensable in order to find the optimum technical way to make use of the physical potential of superconductivity. (orig./MM) [de

  9. Influence of magneto-electric coefficient for magnetic and electric charge injection properties in magneto-electric MIS capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Yokota, T; Tsuboi, Y; Imura, R; Kito, S; Gomi, M, E-mail: yokota.takeshi@nitech.ac.jp [Department of Material Science and Engineering, Graduate School of Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya City, Aichi, 466-8555 (Japan)

    2011-10-29

    We investigated the electric charge injection properties of a floating-gate type metal-insulator Si capacitor having different-ME gate insulators. The samples showed charge-injection type behaviour in capacitance-voltage curves, and it was revealed that the amount of injected charges can be controlled by the application of an external magnetic field. The sample having a high-ME-coefficient gate insulator showed stepwise capacitance-voltage curves unlike the normal one. These results indicate that this capacitor, which employs a magnetic gate insulator, has the potential to be used in multilevel memory by the application of an external magnetic field.

  10. Improving sensitivity to magnetic fields and electric dipole moments by using measurements of individual magnetic sublevels

    Science.gov (United States)

    Tang, Cheng; Zhang, Teng; Weiss, David S.

    2018-03-01

    We explore ways to use the ability to measure the populations of individual magnetic sublevels to improve the sensitivity of magnetic field measurements and measurements of atomic electric dipole moments (EDMs). When atoms are initialized in the m =0 magnetic sublevel, the shot-noise-limited uncertainty of these measurements is 1 /√{2 F (F +1 ) } smaller than that of a Larmor precession measurement. When the populations in the even (or odd) magnetic sublevels are combined, we show that these measurements are independent of the tensor Stark shift and the second order Zeeman shift. We discuss the complicating effect of a transverse magnetic field and show that when the ratio of the tensor Stark shift to the transverse magnetic field is sufficiently large, an EDM measurement with atoms initialized in the superposition of the stretched states can reach the optimal sensitivity.

  11. Electric-magnetic duality as a secondary symmetry

    International Nuclear Information System (INIS)

    Brandt, R.A.; Young, K.

    1980-01-01

    In both the abelian and non-abelian classical point magnetic monopole theories, electric current conservation is a consequence of gauge invariance, but, since there is no magnetic gauge group, magnetic current conservation is not a Noether-type conservation law. In the abelian models, the equations of motion (but not the lagrangian) are invariant to the duality rotations in electric-magnetic charge space, but this is not the case in the non-abelian models. In an attempt to understand these and related points, we introduce a generalization of Noether's theorem. Consider a physical system described by a set of variables THETA and characterized by a lagrangian density L(THETA). A transormation law THETA → G THETA which leaves L invariant leads to a conserved current Jsub(μ)(THETA). We then call G a primary symmetry. A second transformation law THETA → D THETA which leaves the equations of motion, but not L, invariant then leads to another conserved current Jsub(μ)(D THETA). We then call D a secondary symmetra. Our main point is that Jsub(μ) (D THETA) may be conserved even if the equations of motion are not invariant under D. All that is required is that the change of the equations of motion under D is perpendicular (in the field space) to the change of the fields under G. Then we call D an incomplete secondary symmetry. We show that in both the abelian and non-abelian monopole theories, duality is an incomplete secondary symmetry whose associated conservation law is magnetic current conservation. Thus it is the interpretation of duality as a secondary symmetry which explains magnetic current conservation and which generalizes from the abelian theories to the non-abelian ones. This suggests that magnetic current conservation may remain valid in quantum field theory. (orig.)

  12. Probe branes thermalization in external electric and magnetic fields

    International Nuclear Information System (INIS)

    Ali-Akbari, M.; Ebrahim, H.; Rezaei, Z.

    2014-01-01

    We study thermalization on rotating probe branes in AdS 5 ×S 5 background in the presence of constant external electric and magnetic fields. In the AdS/CFT framework this corresponds to thermalization in the flavour sector in field theory. The horizon appears on the worldvolume of the probe brane due to its rotation in one of the sphere directions. For both electric and magnetic fields the behaviour of the temperature is independent of the probe brane dimension. We also study the open string metric and the fluctuations of the probe brane in such a set-up. We show that the temperatures obtained from open string metric and observed by the fluctuations are larger than the one calculated from the induced metric

  13. Quiver gauge theory and extended electric-magnetic duality

    International Nuclear Information System (INIS)

    Maruyoshi, Kazunobu

    2009-01-01

    We construct N = 1 A-D-E quiver gauge theory with the gauge kinetic term which depends on the adjoint chiral superfields, as a low energy effective theory on D5-branes wrapped on 2-cycles of Calabi-Yau 3-fold in IIB string theory. The field-dependent gauge kinetic term can be engineered by introducing B-field which holomorphically varies on the base space (complex plane) of Calabi-Yau. We consider Weyl reflection on A-D-E node, which acts non-trivially on the gauge kinetic term. It is known that Weyl reflection is related to N = 1 electric-magnetic duality. Therefore, the non-trivial action implies an extension of the electric-magnetic duality to the case with the field-dependent gauge kinetic term. We show that this extended duality is consistent from the field theoretical point of view. We also consider the duality map of the operators.

  14. p-brane dyons and electric-magnetic duality

    International Nuclear Information System (INIS)

    Deser, S.; Henneaux, M.; Teitelboim, C.

    1998-01-01

    We discuss dyons, charge quantization and electric-magnetic duality for self-interacting, abelian, p-form theories in the space-time dimensions D=2(p+1) where dyons can be present. The corresponding quantization conditions and duality properties are strikingly different depending on whether p is odd or even. If p is odd one has the familiar e anti g-g anti e=2πnℎ, whereas for even p one finds the opposite relative sign, e anti g+g anti e=2πnℎ. These conditions are obtained by introducing Dirac strings and taking due account of the multiple connectedness of the configuration space of the strings and the dyons. A two-potential formulation of the theory that treats the electric and magnetic sources on the same footing is also given. Our results hold for arbitrary gauge invariant self-interaction of the fields and are valid irrespective of their duality properties. (orig.)

  15. Small hydro-electric potential: west Poverty Bay region

    Energy Technology Data Exchange (ETDEWEB)

    1981-07-01

    This study has identified six schemes in the Bay of Plenty Electric Power Board area and two in the Poverty Bay Electric Power Board area, of which five and one, respectively, are below the economic limit of $2400/kW suggested by the Ministry of Works and Development as of December 1979. Of these, only three appear both economically and environmentally acceptable. The Takaputahi and Torere schemes are not likely to proceed if the Ministry of Works and Development continue with their plans to develop the Motu River. Furthermore, the Motu Falls scheme is unlikely to proceed for environmental reasons. The schemes identified are not very attractive on the national scale and could not be justified on local terms. However, a detailed feasibility study of the Takaputahi/Torere diversion should be undertaken prior to a decision being made to proceed with the Motu development, or if the proposals are dropped. The present low load and slow growth of the area is such that prior to a small hydro-electric scheme being built, there would need to be an established demand for power.

  16. Assessing students’ conceptual knowledge of electricity and magnetism

    Directory of Open Access Journals (Sweden)

    Michele W. McColgan

    2017-10-01

    Full Text Available We present the Electricity and Magnetism Conceptual Assessment (EMCA, a new assessment aligned with second-semester introductory physics courses. Topics covered include electrostatics, electric fields, circuits, magnetism, and induction. We have two motives for writing a new assessment. First, we find other assessments such as the Brief Electricity and Magnetism Assessment and the Conceptual Survey on Electricity and Magnetism not well aligned with the topics and content depth of our courses. We want to test introductory physics content at a level appropriate for our students. Second, we want the assessment to yield scores and gains comparable to the widely used Force Concept Inventory (FCI. After five testing and revision cycles, the assessment was finalized in early 2015 and is available online. We present performance results for a cohort of 225 students at Siena College who were enrolled in our algebra- and calculus-based physics courses during the spring 2015 and 2016 semesters. We provide pretest, post-test, and gain analyses, as well as individual question and whole test statistics to quantify difficulty and reliability. In addition, we compare EMCA and FCI scores and gains, and we find that students’ FCI scores are strongly correlated with their performance on the EMCA. Finally, the assessment was piloted in an algebra-based physics course at George Washington University (GWU. We present performance results for a cohort of 130 GWU students and we find that their EMCA scores are comparable to the scores of students in our calculus-based physics course.

  17. A preon model with hidden electric and magnetic type charges

    International Nuclear Information System (INIS)

    Pati, J.C.; Strathdee, J.

    1980-11-01

    The U(1) x U(1) binding forces in an earlier preonic composite model of quarks and leptons are interpreted as arising from hidden electric and magnetic type charges. The preons may possess intrinsic spin zero; the half-integer spins of the composites being contributed by the force field. The quark-lepton gauge symmetry is interpreted as an effective low-energy symmetry arising at the composite level. Some remarks are made regarding the possible composite nature of the graviton. (author)

  18. Impacts of Interior Permanent Magnet Machine Technology for Electric Vehicles

    Science.gov (United States)

    2012-01-01

    corrosion constraints of magnets  Minimum gear and more direct drive  Regenerative braking and short charging cycle of batteries  Impulse...be found in limited applications such as, antilock braking system (ABS) of the vehicles. Considering the performance enhancement and reliability of... system forms the backbone of modern society. Electricity and its accessibility is one of the major engineering achievements. In order to maintain and

  19. Energy harvesting concepts for small electric unmanned systems

    Science.gov (United States)

    Qidwai, Muhammad A.; Thomas, James P.; Kellogg, James C.; Baucom, Jared N.

    2004-07-01

    In this study, we identify and survey energy harvesting technologies for small electrically powered unmanned systems designed for long-term (>1 day) time-on-station missions. An environmental energy harvesting scheme will provide long-term, energy additions to the on-board energy source. We have identified four technologies that cover a broad array of available energy sources: solar, kinetic (wind) flow, autophagous structure-power (both combustible and metal air-battery systems) and electromagnetic (EM) energy scavenging. We present existing conceptual designs, critical system components, performance, constraints and state-of-readiness for each technology. We have concluded that the solar and autophagous technologies are relatively matured for small-scale applications and are capable of moderate power output levels (>1 W). We have identified key components and possible multifunctionalities in each technology. The kinetic flow and EM energy scavenging technologies will require more in-depth study before they can be considered for implementation. We have also realized that all of the harvesting systems require design and integration of various electrical, mechanical and chemical components, which will require modeling and optimization using hybrid mechatronics-circuit simulation tools. This study provides a starting point for detailed investigation into the proposed technologies for unmanned system applications under current development.

  20. 75 FR 17036 - Energy Conservation Program: Energy Conservation Standards for Small Electric Motors; Correction

    Science.gov (United States)

    2010-04-05

    ... Conservation Program: Energy Conservation Standards for Small Electric Motors; Correction AGENCY: Office of... standards for small electric motors, which was published on March 9, 2010. In that final rule, the U.S... titled ``Energy Conservation Standards for Small Electric Motors.'' 75 FR 10874. Since the publication of...

  1. 10 CFR 431.446 - Small electric motors energy conservation standards and their effective dates. [Reserved

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Small electric motors energy conservation standards and... CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Small Electric Motors Energy Conservation Standards § 431.446 Small electric motors energy conservation standards and their...

  2. Exploiting Electric and Magnetic Fields for Underwater Characterization

    Science.gov (United States)

    2011-03-01

    geophysical surveys are primarily limited to passive magnetic systems towed from a surface vessel. These systems utilize fluxgate , Overhauser, or atomic... magnetometer sensors, often deployed in arrays towed from the stern of small to moderate-size vessels. Active source electromagnetic methods have been

  3. Optimization of Photospheric Electric Field Estimates for Accurate Retrieval of Total Magnetic Energy Injection

    Science.gov (United States)

    Lumme, E.; Pomoell, J.; Kilpua, E. K. J.

    2017-12-01

    Estimates of the photospheric magnetic, electric, and plasma velocity fields are essential for studying the dynamics of the solar atmosphere, for example through the derivative quantities of Poynting and relative helicity flux and using the fields to obtain the lower boundary condition for data-driven coronal simulations. In this paper we study the performance of a data processing and electric field inversion approach that requires only high-resolution and high-cadence line-of-sight or vector magnetograms, which we obtain from the Helioseismic and Magnetic Imager (HMI) onboard Solar Dynamics Observatory (SDO). The approach does not require any photospheric velocity estimates, and the lacking velocity information is compensated for using ad hoc assumptions. We show that the free parameters of these assumptions can be optimized to reproduce the time evolution of the total magnetic energy injection through the photosphere in NOAA AR 11158, when compared to recent state-of-the-art estimates for this active region. However, we find that the relative magnetic helicity injection is reproduced poorly, reaching at best a modest underestimation. We also discuss the effect of some of the data processing details on the results, including the masking of the noise-dominated pixels and the tracking method of the active region, neither of which has received much attention in the literature so far. In most cases the effect of these details is small, but when the optimization of the free parameters of the ad hoc assumptions is considered, a consistent use of the noise mask is required. The results found in this paper imply that the data processing and electric field inversion approach that uses only the photospheric magnetic field information offers a flexible and straightforward way to obtain photospheric magnetic and electric field estimates suitable for practical applications such as coronal modeling studies.

  4. Nickel recovery from electric arc furnace slag by magnetic separation

    Directory of Open Access Journals (Sweden)

    Sakaroglou Marianna

    2017-01-01

    Full Text Available During the pyrometallurgical treatment of the nickel-bearing laterite in the plant of G.M.M. S.A. LARCO, slag is produced after treatment in electric-arc furnace (EAF that contains 0.10 to 0.20 % Ni. Taking into account the great quantity of slag produced per year, the recovery of nickel from the EAF slag will add benefits to the entire process. The target of the current work is to investigate the possibility of nickel recovery from EAF slag by magnetic separation. To meet the target, the effect of the following parameters was studied: grain size, magnetic field intensity, thickness of slag layer, moisture content, and re-grinding of the coarser slag particles. The results show that it is possible to obtain a magnetic product with nickel grade close to that of the primary raw material or even better, with sufficient nickel recovery.

  5. Developmental effects of extremely low frequency electric and magnetic fields

    International Nuclear Information System (INIS)

    Juutilainen, J.

    2003-01-01

    Developmental effects of extremely low frequency (ELF) electric and magnetic fields are briefly reviewed in this paper. The results of animal studies on ELF electric fields are rather consistent, and do not suggest adverse effects on development. The results of studies on ELF magnetic fields suggest effects on bird embryo development, but not consistently in all studies. Results from experiments with other non-mammalian species have also suggested effects on developmental stability. In mammals, pre-natal exposure to ELF magnetic fields does not result in strong adverse effects on development. The only finding that shows some consistency is increase of minor skeleton alterations. Epidemiological studies do not establish an association between human adverse pregnancy outcomes and maternal exposure to ELF fields, although a few studies have reported increased risks associated with some characteristics of magnetic field exposure. Taken as a whole, the results do not show strong adverse effects on development. However, additional studies on the suggested subtle effects on developmental stability might increase our understanding of the sensitivity of organisms to weak ELF fields. (author)

  6. Electrical and Magnetic Performance of the LHC Short Straight Sections

    CERN Document Server

    Sanfilippo, S; Bottura, L; Buzio, M; Coccoli, M; García-Pérez, J; Pugnat, P; Sammut, N; Siemko, A; Smirnov, N; Stafiniak, A; Wildner, E

    2006-01-01

    The Short Straight Section (SSS) for the Large Hadron Collider arcs, containing in a common cryostat the lattice quadrupoles and correction magnets, have now entered series production. The foremost features of the lattice quadrupole magnets are a two-in-one structure containing two 56 mm aperture, two-layers coils wound from 15.1 mm wide NbTi cables, enclosed by the stainless steel collars and ferromagnetic yoke, and inserted into the inertia tube. Systematic cryogenic tests are performed at CERN in order to qualify these magnets with respect to their cryogenic and electrical integrity, the quench performance and the field quality in all operating conditions. This paper reports the main results obtained during tests and measurements in superfluid helium. The electrical characteristics, the insulation measurements and the quench performance are compared to the specifications and expected performances for these magnets. The field in the main quadrupole is measured using three independent systems: 10-m lon...

  7. Peltier heat of a small polaron in a magnetic semiconductor

    International Nuclear Information System (INIS)

    Liu, N.H.; Emin, D.

    1985-01-01

    For the first time the heat transported with a small polaron in both antiferromagnetic and ferromagnetic semiconductors is calculated. This heat, the Peltier heat, π, is obtained from the change of the entropy of the total system upon introduction of a charge carrier. We explicitly consider both the intrasite and intersite exchange interactions between a small polaron and the interacting spins of a spin-1/2 magnet. There are two competing magnetic contributions to the Peltier heat. First, adding the carrier increases the spin entropy of the system. This provides a positive contribution to π. Second, the exchange between the carrier and the sites about it enhances the exchange binding between these sites. This reduces the energetically allowable spin configurations and provides a negative contribution to π. At extremely high temperatures when kT exceeds the intrasite exchange energy, the first effect dominates. Then π is simply augmented by kT ln 2. However, well below the magnetic transition temperature the second effect dominates. In the experimentally accessible range between these limits both effects are comparable and sizable. The net magnetic contribution to the Peltier heat rises with temperature. Thus, a carrier's interactions with its magnetic environment produces a significant and distinctive contribution to its Peltier heat

  8. Peltier heat of a small polaron in a magnetic semiconductor

    International Nuclear Information System (INIS)

    Liu, N.L.H.; Emin, D.

    1984-01-01

    The heat transported with a small polaron in both antiferromagnetic and ferromagnetic semiconductors is calculated. This heat, the Peltier heat, π, is obtained from the change of the entropy of the total system upon introduction of a charge carrier. We explicitly consider both the intrasite and intersite exchange interactions between a small polaron and the interacting spins of a spin-1/2 magnet. There are two competing magnetic contributions to the Peltier heat. First, adding the carrier increases the spin entropy of the system. This provides a positive contribution to π. Second, the exchange between the carrier and the sites about it enhances the exchange binding between these sites. This reduces the energetically allowable spin configurations and provides a negative contribution to π. At extremely high temperature when kT exceeds the intrasite exchange energy, the first effect dominates. Then π is simply augmented by kTln2. However, well below the magnetic transition temperature the second effect dominates. In the experimentally accessible range between these limits both effects are comparable and sizable. The net magnetic contribution to the Peltier heat rises with temperature. Thus, a carrier's interactions with its magnetic environment produces a significant and distinctive contribution to its Peltier heat

  9. Effect of small quantity of chromium on the electrical, magnetic and magnetocaloric properties of Pr{sub 0.7}Ca{sub 0.3}Mn{sub 0.98}Cr{sub 0.02}O{sub 3} manganite

    Energy Technology Data Exchange (ETDEWEB)

    Bettaibi, A.; Rahmouni, H. [Universite de Gabes, Laboratoire de Physique des Materiaux et des Nanomateriaux appliquee a l' Environnement, Faculte des Sciences de Gabes cite Erriadh, Gabes (Tunisia); M' nassri, R. [Kairouan University, Higher Institute of Applied Sciences and Technology of Kasserine, Kasserine (Tunisia); Universite de Monastir, Laboratoire de Physico-Chimie des Materiaux, Departement de Physique, Faculte des Sciences de Monastir, Monastir (Tunisia); Selmi, A.; Cheikhrouhou, A. [Sfax University, Laboratory of Physics of Materials, Faculty of Sciences of Sfax, Sfax (Tunisia); Khirouni, K. [Kairouan University, Higher Institute of Applied Sciences and Technology of Kasserine, Kasserine (Tunisia); Chniba Boudjada, N. [Institut NEEL, Grenoble Cedex 09 (France)

    2016-03-15

    Structural, electrical and thermomagnetic properties of Pr{sub 0.7}Ca{sub 0.3}Mn{sub 0.98}Cr{sub 0.02}O{sub 3} were investigated. Sample was prepared by solid-state reaction method. X-ray diffraction revealed that the sample crystallizes in the orthorhombic system with Pnma space group. Electrical conductivity and complex impedance studies of Pr{sub 0.7}Ca{sub 0.3}Mn{sub 0.98}Cr{sub 0.02}O{sub 3} system are analyzed. The investigated compound exhibits a semiconductor behavior in the whole explored temperature range. From 100 to 206 K, the increase in DC conductance is more than two decade. At higher temperatures, the conductance varies slowly and a saturation region appears. The conduction mechanism is found to be governed by small polaron hopping process which is explained by the short range thermally activated energy. Conductance spectrum is well described by Jonsher law, and the temperature dependence of the frequency exponent confirms that conduction mechanism is governed by hopping process of the localized carriers. Using complex impedance analysis, the compound is modeled by an electrical equivalent circuit. Also, such analysis confirms the contribution of grain boundary to the transport properties. The substitution of Mn by 2 % Cr destroyed the charge order state observed in the parent compound and induced a ferromagnetic phase at low temperatures. For a magnetic field change of 5 T, the material shows a maximum magnetic entropy change ∇S {sup max} = 2.69 J kg{sup -1} K{sup -1} with a full width at half maximum δ {sub TFWHM} = 145 K, and a relative cooling power RCP = 389 J kg{sup -1}. Pr{sub 0.7}Ca{sub 0.3}Mn{sub 0.98}Cr{sub 0.02}O{sub 3} material demonstrates potential proprieties to be used in electronic and thermal devices and as magnetic refrigerant. (orig.)

  10. Effect of electric and magnetic fields on current-voltage characteristics of a lyotropic liquid crystal

    International Nuclear Information System (INIS)

    Minasyants, M.Kh.; Badalyan, G. G.; Shahinian, A. A.

    1997-01-01

    The effect of electric and magnetic fields on current-voltage characteristics is studied for the lamellar phase in the lyotropic liquid-crystal sodium pentadecylsulfonate (SPDS)-water and lecithin-water systems. It has been found that the current-voltage characteristics of both systems have hysteresis. In the case of ionogenic SPDS, the hysteresis is formed due to ion current caused by the spatial reorientation of domains consisting of parallel lamellar fragments; in the case of lecithin, whose molecules contain dipoles, the hysteresis is formed due to the spatial reorientation of domains caused by the interaction of the resultant dipole moment of the domains with the electric field. It is shown that the introduction into lamellae of cetylpyridine bromide, which has an intrinsic magnetic moment, changes the resultant magnetic moment of domains and, thus, also the hysteresis loop of the current-voltage characteristic. The systems studied show the 'memory' effect with respect to both the electric and magnetic fields. Field-induced processes of domain reorientation were recorded by the method of small-angle x-ray scattering

  11. Magnetic and electric dipole moments of the H 3Δ1 state in ThO

    International Nuclear Information System (INIS)

    Vutha, A. C.; Kirilov, E.; DeMille, D.; Spaun, B.; Gurevich, Y. V.; Hutzler, N. R.; Doyle, J. M.; Gabrielse, G.

    2011-01-01

    The metastable H 3 Δ 1 state in the thorium monoxide (ThO) molecule is highly sensitive to the presence of a CP-violating permanent electric dipole moment of the electron (eEDM) [E. R. Meyer and J. L. Bohn, Phys. Rev. A 78, 010502 (2008)]. The magnetic dipole moment μ H and the molecule-fixed electric dipole moment D H of this state are measured in preparation for a search for the eEDM. The small magnetic moment μ H =8.5(5)x10 -3 μ B displays the predicted cancellation of spin and orbital contributions in a 3 Δ 1 paramagnetic molecular state, providing a significant advantage for the suppression of magnetic field noise and related systematic effects in the eEDM search. In addition, the induced electric dipole moment is shown to be fully saturated in very modest electric fields (<10 V/cm). This feature is favorable for the suppression of many other potential systematic errors in the ThO eEDM search experiment.

  12. Nonequilibrium Thermodynamic Treatment of a Warm Plasma in Strong Magnetic and Electric Fields

    International Nuclear Information System (INIS)

    Abourabia, A.M.; Shahein, R.A.

    2008-01-01

    In the framework of the irreversible thermodynamics we study a rarefied and collisional warm electron plasma under the effects of external strong magnetic and electric fields which generate small wave amplitudes. We adopt the linear theory and normal mode solution in the MHD model to calculate the perturbations in pressure, mass density, components of velocity, electric and magnetic fields. By applying the second law of thermodynamics it is concluded that the change in the internal energy of the plasma particles predicts whether they gain from or lose energy to the generated waves .The obtained results agree with the physical ground bounded by the positive nature of the entropy production. The predictions have been carried out within the range of the frequency of the generated waves and the distance from the Debye sphere

  13. Cryogenic magnetic coil and superconducting magnetic shield for neutron electric dipole moment searches

    Science.gov (United States)

    Slutsky, S.; Swank, C. M.; Biswas, A.; Carr, R.; Escribano, J.; Filippone, B. W.; Griffith, W. C.; Mendenhall, M.; Nouri, N.; Osthelder, C.; Pérez Galván, A.; Picker, R.; Plaster, B.

    2017-08-01

    A magnetic coil operated at cryogenic temperatures is used to produce spatial, relative field gradients below 6 ppm/cm, stable for several hours. The apparatus is a prototype of the magnetic components for a neutron electric dipole moment (nEDM) search, which will take place at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory using ultra-cold neutrons (UCN). That search requires a uniform magnetic field to mitigate systematic effects and obtain long polarization lifetimes for neutron spin precession measurements. This paper details upgrades to a previously described apparatus [1], particularly the introduction of super-conducting magnetic shielding and the associated cryogenic apparatus. The magnetic gradients observed are sufficiently low for the nEDM search at SNS.

  14. Effects of AC Electric Field on Small Laminar Nonpremixed Flames

    KAUST Repository

    Xiong, Yuan

    2015-04-01

    Electric field can be a viable method in controlling various combustion properties. Comparing to traditional actuators, an application of electric field requires very small power consumption. Especially, alternating current (AC) has received attention recently, since it could modulate flames appreciably even for the cases when direct current (DC) has minimal effects. In this study, the effect of AC electric fields on small coflow diffusion flames is focused with applications of various laser diagnostic techniques. Flow characteristics of baseline diffusion flames, which corresponds to stationary small coflow diffusion flames when electric field is not applied, were firstly investigated with a particular focus on the flow field in near-nozzle region with the buoyancy force exerted on fuels due to density differences among fuel, ambient air, and burnt gas. The result showed that the buoyancy force exerted on the fuel as well as on burnt gas significantly distorted the near-nozzle flow-fields. In the fuels with densities heavier than air, recirculation zones were formed very close to the nozzle exit. Nozzle heating effect influenced this near-nozzle flow-field particularly among lighter fuels. Numerical simulations were also conducted and the results showed that a fuel inlet boundary condition with a fully developed velocity profile for cases with long fuel tubes should be specified inside the fuel tube to obtain satisfactory agreement in both the flow and temperature fields with those from experiment. With sub-critical AC applied to the baseline flames, particle image velocimetry (PIV), light scattering, laser-induced incandescence (LII), and laser-induced fluores- cence (LIF) techniques were adopted to identify the flow field and the structures of OH, polycyclic aromatic hydrocarbons (PAHs), soot zone. Under certain AC condi- tions of applied voltage and frequency, the distribution of PAHs and the flow field near the nozzle exit were drastically altered from the

  15. Small clusters with anisotropic antiferromagnetic exchange in a magnetic field

    International Nuclear Information System (INIS)

    Parkinson, J B; Elliott, R J; Timonen, J

    2004-01-01

    We consider small symmetric clusters of magnetic atoms (spins) with anisotropic exchange interaction between the atoms in a magnetic field at zero temperature. The inclusion of the anisotropy leads to a wealth of different phases as a function of the applied magnetic field. These are not phases in the thermodynamic sense with critical properties but rather physical structures with different arrangements of the spins and hence different symmetries. We study the spatial symmetry of these phases, for the classical and quantum cases. Results are presented mainly for three frustrated systems, the triangle, the tetrahedron and the five-atom ring, which have many interesting features. In the classical limit we obtain phase diagrams in which some of the phase changes occur because of energy crossings and others due to energy bifurcations, corresponding to 'first-' and 'second-order' changes. In the quantum case we show how the symmetries of the states are related to the corresponding classical symmetries

  16. Plasma rotation by electric and magnetic fields in a discharge cylinder

    Science.gov (United States)

    Wilhelm, H. E.; Hong, S. H.

    1977-01-01

    A theoretical model for an electric discharge consisting of a spatially diverging plasma sustained electrically between a small ring cathode and a larger ring anode in a cylindrical chamber with an axial magnetic field is developed to study the rotation of the discharge plasma in the crossed electric and magnetic fields. The associated boundary-value problem for the coupled partial differential equations which describe the electric potential and the plasma velocity fields is solved in closed form. The electric field, current density, and velocity distributions are discussed in terms of the Hartmann number and the Hall coefficient. As a result of Lorentz forces, the plasma rotates with speeds as high as 1 million cm/sec around its axis of symmetry at typical conditions. As an application, it is noted that rotating discharges of this type could be used to develop a high-density plasma-ultracentrifuge driven by j x B forces, in which the lighter (heavier) ion and atom components would be enriched in (off) the center of the discharge cylinder.

  17. Application of magnetic pulse forming to aeronautic small pieces

    Science.gov (United States)

    Sow, C.; Bazin, G.; Daniel, D.; Bon, E.; Priem, D.; Racineux, G.

    2018-05-01

    Stelia Aerospace company is specialized in the forming of small (Lmax 1000 mm) sheets for the aerospace industry. In order to diversify the production facilities of Stelia Aerospace we evaluated the capacity of the magnetic pulse forming to produce small parts. The material used is the aluminum alloy 2024-T4. The sheets used have a thickness of 1 mm, 2 mm and 1.6 mm. Stelia Aerospace manufactures more than 100 different small parts but they are all made up of a limited set of elementary geometries. These elementary geometries include: straight and interrupted straight fallen edges, concave and convex fallen edges, fallen edges holes and joggling. In this paper we present the work we have done to develop forming tools for one of these elementary geometries, the straight fallen edge. Special attention is paid to the geometric and metallurgic quality of parts. In order to evaluate dimensional reproducibility of the process, smalls series of parts were produced.

  18. Electric-Field-Induced Magnetization Reversal in a Ferromagnet-Multiferroic Heterostructure

    Science.gov (United States)

    Heron, J. T.; Trassin, M.; Ashraf, K.; Gajek, M.; He, Q.; Yang, S. Y.; Nikonov, D. E.; Chu, Y.-H.; Salahuddin, S.; Ramesh, R.

    2011-11-01

    A reversal of magnetization requiring only the application of an electric field can lead to low-power spintronic devices by eliminating conventional magnetic switching methods. Here we show a nonvolatile, room temperature magnetization reversal determined by an electric field in a ferromagnet-multiferroic system. The effect is reversible and mediated by an interfacial magnetic coupling dictated by the multiferroic. Such electric-field control of a magnetoelectric device demonstrates an avenue for next-generation, low-energy consumption spintronics.

  19. Magnetic characterization of the stator core of a high-speed motor made of an ultrathin electrical steel sheet using the magnetic property evaluation system

    Directory of Open Access Journals (Sweden)

    Mohachiro Oka

    2018-04-01

    Full Text Available Recently, the application areas for electric motors have been expanding. For instance, electric motors are used in new technologies such as rovers, drones, cars, and robots. The motor used in such machinery should be small, high-powered, highly-efficient, and high-speed. In such motors, loss at high-speed rotation must be especially minimal. Eddy-current loss in the stator core is known to increase greatly during loss at high-speed rotation of the motor. To produce an efficient high-speed motor, we are developing a stator core for a motor using an ultrathin electrical steel sheet with only a small amount of eddy-current loss. Furthermore, the magnetic property evaluation for efficient, high-speed motor stator cores that use conventional commercial frequency is insufficient. Thus, we made a new high-speed magnetic property evaluation system to evaluate the magnetic properties of the efficient high-speed motor stator core. This system was composed of high-speed A/D converters, D/A converters, and a high-speed power amplifier. In experiments, the ultrathin electrical steel sheet dramatically suppressed iron loss and, in particular, eddy-current loss. In addition, a new high-speed magnetic property evaluation system accurately evaluated the magnetic properties of the efficient high-speed motor stator core.

  20. Magnetic characterization of the stator core of a high-speed motor made of an ultrathin electrical steel sheet using the magnetic property evaluation system

    Science.gov (United States)

    Oka, Mohachiro; Enokizono, Masato; Mori, Yuji; Yamazaki, Kazumasa

    2018-04-01

    Recently, the application areas for electric motors have been expanding. For instance, electric motors are used in new technologies such as rovers, drones, cars, and robots. The motor used in such machinery should be small, high-powered, highly-efficient, and high-speed. In such motors, loss at high-speed rotation must be especially minimal. Eddy-current loss in the stator core is known to increase greatly during loss at high-speed rotation of the motor. To produce an efficient high-speed motor, we are developing a stator core for a motor using an ultrathin electrical steel sheet with only a small amount of eddy-current loss. Furthermore, the magnetic property evaluation for efficient, high-speed motor stator cores that use conventional commercial frequency is insufficient. Thus, we made a new high-speed magnetic property evaluation system to evaluate the magnetic properties of the efficient high-speed motor stator core. This system was composed of high-speed A/D converters, D/A converters, and a high-speed power amplifier. In experiments, the ultrathin electrical steel sheet dramatically suppressed iron loss and, in particular, eddy-current loss. In addition, a new high-speed magnetic property evaluation system accurately evaluated the magnetic properties of the efficient high-speed motor stator core.

  1. Small-scale electric generators for arctic applications

    International Nuclear Information System (INIS)

    Lamp, T.R.

    1995-01-01

    Forest fires that have endangered remote US Air Force sites equipped with radioisotope thermoelectric generators (RTGs) has prompted the assessment of power generating systems as substitutes for RTGs in small scale (10--120 watt) applications. A team of scientists and engineers of the US Air Forces' Wright Laboratory conductd an assessment of electrical power technologies for use by the Air Force in remote, harsh environments. The surprisingly high logistics costs of operating fossil fuel generators resulted in the extension of the assessment to non-RTG sites. The candidate power sources must operate unattended for long periods at a high level of operational reliability. Selection of the optimum power generation technology is complicated and heavily driven by the severe operating environment and compounded by the remoteness of the location. It is these site-related characteristics, more than any other, that drive the selection of a safe and economical power source for Arctic applications. A number of proven power generation technologies were evaluated. The assessment concluded that RGTs are clearly the safest, most reliable, and most economical approach to supplying electrical power for remote, difficult to assess locations. The assessment also indicated that the logistics costs associated with combustion driven generator systems could be substantially reduced through the use of conversion technologies which have been previously developed for space power applications. copyright 1995 American Institute of Physics

  2. ELF magnetic fields in electric and gasoline-powered vehicles.

    Science.gov (United States)

    Tell, R A; Sias, G; Smith, J; Sahl, J; Kavet, R

    2013-02-01

    We conducted a pilot study to assess magnetic field levels in electric compared to gasoline-powered vehicles, and established a methodology that would provide valid data for further assessments. The sample consisted of 14 vehicles, all manufactured between January 2000 and April 2009; 6 were gasoline-powered vehicles and 8 were electric vehicles of various types. Of the eight models available, three were represented by a gasoline-powered vehicle and at least one electric vehicle, enabling intra-model comparisons. Vehicles were driven over a 16.3 km test route. Each vehicle was equipped with six EMDEX Lite broadband meters with a 40-1,000 Hz bandwidth programmed to sample every 4 s. Standard statistical testing was based on the fact that the autocorrelation statistic damped quickly with time. For seven electric cars, the geometric mean (GM) of all measurements (N = 18,318) was 0.095 µT with a geometric standard deviation (GSD) of 2.66, compared to 0.051 µT (N = 9,301; GSD = 2.11) for four gasoline-powered cars (P electric vehicles covered the same range as personal exposure levels recorded in that study. All fields measured in all vehicles were much less than the exposure limits published by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the Institute of Electrical and Electronics Engineers (IEEE). Future studies should include larger sample sizes representative of a greater cross-section of electric-type vehicles. Copyright © 2012 Wiley Periodicals, Inc.

  3. Interplay between electric and magnetic effect in adiabatic polaritonic systems

    KAUST Repository

    Alabastri, Alessandro; Toma, Andrea; Liberale, Carlo; Chirumamilla, Manohar; Giugni, Andrea; De Angelis, Francesco De; Das, Gobind; Di Fabrizio, Enzo M.; Proietti Zaccaria, Remo

    2013-01-01

    We report on the possibility of realizing adiabatic compression of polaritonic wave on a metallic conical nano-structure through an oscillating electric potential (quasi dynamic regime). By comparing this result with an electromagnetic wave excitation, we were able to relate the classical lighting-rod effect to adiabatic compression. Furthermore, we show that while the magnetic contribution plays a marginal role in the formation of adiabatic compression, it provides a blue shift in the spectral region. In particular, magnetic permeability can be used as a free parameter for tuning the polaritonic resonances. The peculiar form of adiabatic compression is instead dictated by both the source and the metal permittivity. The analysis is performed by starting from a simple electrostatic system to end with the complete electromagnetic one through intermediate situations such as the quasi-electrostatic and quasi-dynamic regimes. Each configuration is defined by a particular set of equations which allows to clearly determine the individual role played by the electric and magnetic contribution in the generation of adiabatic compression. We notice that these findings can be applied for the realization of a THz nano-metric generator. © 2013 Optical Society of America.

  4. On the electric and magnetic field generation in expanding plasmas

    International Nuclear Information System (INIS)

    Gielen, H.J.G.

    1989-01-01

    This thesis deals with the generation of electric and magnetic fields in expanding plasmas. The theoretical model used to calculate the different field quantities in such plasmas is discussed in part 1 and is in fact an analysis of Ohm's law. A general method is given that decomposes each of the forces terms in Ohm's law in a component that induces a charge separation in the plasma and in a component that can drive current. This decomposition is unambiguous and depends upon the boundary conditions for the electric potential. It is shown that in calculating the electromagnetic field quantities in a plasma that is located in the vicinity of a boundary that imposes constraints on the electric potential, Ohm's law should be analyzed instead of the so-called induction equation. Three applications of the model are presented. A description is given of the unipolar arc discharge where both plasma and sheath effects have been taken into account. Secondly a description is presented of the plasma effects of a cathode spot. The third application of the model deals with the generation of magnetic fields in laser-produced plasmas. The second part of this thesis describes the experiments on a magnetized argon plasma expanding from a cascaded arc. With the use of spectroscopic techniques the electron density, ion temperature and the rotation velocity profiles of the ion gas have been determined. The magnetic field generated by the plasma has been measured with the use of the Zeeman effect. Depending on the channel diameter of the nozzle of the cascaded arc, self-generated magnetic fields with axial components of the order of 1% of the externally applied mangetic field have been observed. From the measured ion rotation it has been concluded that this magnetic field is mainly generated by azimuthal electron currents. The corresponding azimuthal current density is of the order of 15% of the axial current density. The observed ion rotation is caused by electron-ion friction. (author

  5. Small-Scale Dayside Magnetic Reconnection Analysis via MMS

    Science.gov (United States)

    Pritchard, K. R.; Burch, J. L.; Fuselier, S. A.; Webster, J.; Genestreti, K.; Torbert, R. B.; Rager, A. C.; Phan, T.; Argall, M. R.; Le Contel, O.; Russell, C. T.; Strangeway, R. J.; Giles, B. L.

    2017-12-01

    The Magnetospheric Multiscale (MMS) mission has the primary objective of understanding the physics of the reconnection electron diffusion region (EDR), where magnetic energy is transformed into particle energy. In this poster, we present data from an EDR encounter that occurred in late December 2016 at approximately 11:00 MLT with a moderate guide field. The spacecraft were in a tetrahedral formation with an average inter-spacecraft distance of approximately 7 kilometers. During this event electron crescent-shaped distributions were observed in the electron stagnation region as is typical for asymmetric reconnection. Based on the observed ion velocity jets, the spacecraft traveled just south of the EDR. Because of the close spacecraft separation, fairly accurate computation of the Hall, electron pressure divergence, and electron inertia components of the reconnection electric field could be made. In the region of the crescent distributions good agreement was observed, with the strongest component being the normal electric field and the most significant sources being electron pressure divergence and the Hall electric field. While the strongest currents were in the out-of-plane direction, the dissipation was strongest in the normal direction because of the larger magnitude of the normal electric field component. These results are discussed in light of recent 3D PIC simulations performed by other groups.

  6. Selective Electron Beam Melting Manufacturing of Electrically Small Antennas

    Directory of Open Access Journals (Sweden)

    Saad Mufti

    2017-11-01

    Full Text Available Real estate pressures in modern electronics have resulted in the need for electrically small antennas, which have subsequently garnered interest amongst researchers and industry alike. These antennas are characterized by their largest dimensions translating to a fraction of the operating wavelength; such a diminutive size comes at the expense of reduced gain and efficiency, and a worse overall match to a corresponding power source. In order to compensate for this deterioration in performance, antenna designers must turn towards increasingly complex and voluminous geometries, well beyond the capabilities of traditional manufacturing techniques. We present voluminous metal antennas, based on a novel inverted-F design, and fabricated using the emergent selective electron beam melting manufacturing technique, a type of powder bed fusion process. As predicted by small antenna theory, simulation results presented show in increase in the antenna’s efficiency as it is voluminously expanded into the third dimension. Measurement results illustrate that key trends observed from simulations are upheld; however, further understanding of the electromagnetic properties of raw materials, in particular how these change during the printing process, is needed. Nevertheless, this type of additive manufacturing technique is suitable for rapid prototyping of novel and complex antenna geometries, and is a promising avenue for further research and maturation.

  7. Variational principles for the static electric and magnetic polarizabilities of anisotropic media with perfect electric conductor inclusions

    International Nuclear Information System (INIS)

    Sjoeberg, Daniel

    2009-01-01

    We present four variational principles for the electric and magnetic polarizabilities for a structure consisting of anisotropic media with perfect electric conductor (PEC) inclusions. From these principles, we derive monotonicity results and upper and lower bounds on the electric and magnetic polarizabilities. When computing the polarizabilities numerically, the bounds can be used as error bounds. The variational principles demonstrate important differences between electrostatics and magnetostatics when PEC bodies are present.

  8. Influence of magnetic field on the electrical breakdown characteristics in cylindrical diode

    International Nuclear Information System (INIS)

    Li Shouzhe; Uhm, Han S.

    2004-01-01

    The influence of magnetic field on the electrical breakdown properties is investigated by applying a magnetic field along the longitudinal direction in a cylindrical diode for two electrical polarities. Breakdown characteristics in a crossed magnetic field are analyzed with the equivalentreduced-electric-field concept and Townsend criterion. The discharge experiment at reduced pressure is carried out in the moderate magnetic field. Experimental investigation is concentrated on the magnetic dependent behavior of the electrical breakdown in the lower pressure side of Paschen's minimum. It is found that the electrical breakdown characteristics with respect to the magnetic field depend on electrical polarity of the cylindrical diode, which is interpreted by taking the gyromotion of the individual electrons in the diode into accounts under the moderate magnetic field in the lower pressure side of Paschen's minimum

  9. Electric control of magnetism in low-dimensional magnets on ferroelectric surfaces

    Directory of Open Access Journals (Sweden)

    Dorj Odkhuu

    2017-05-01

    Full Text Available Employing first-principles electronic structure calculations, we have studied the electric field controls of magnetism and magnetic anisotropy energy (MAE of the Fe adatoms on ferroelectric BaTiO3 and PbTiO3 surfaces. Remarkably, those effects exhibit dependence of the level of coverage as well as adsorption site of Fe atoms. While the magnitude of MAE is shown tunable by ferroelectric polarization in the full coverage of Fe monolayer, the direction of magnetization undergoes a transition from perpendicular to in-plane for the half or lower coverages. This magnetization reorientation is mainly ascribed to the site-dependent Fe d–O p hybridization, as a consequence of the formation of FeTiO2 layer at the surface.

  10. Electrical and magnetic properties of n-alkylurotropinium-polyiodides

    International Nuclear Information System (INIS)

    Fuellbier, H.; Stegemann, H.; Schmidt, L.; Mittag, H.; Petrovskis, G.; Cikmacs, P.; Lusis, A.

    1986-01-01

    Alkylurotropinium polyiodides, UrRI x with Ur=urotropine, x3 and R=C n H 2n+1 with 1 ≥ n ≤ 6; x=5 and n=2; 3; 4; 6; x=7 and n=2; 3; 4 and (UrR) 2 I 8 with n=1;5 were chemically prepared by conversion of the corresponding monoiodides with aqueous solution of KI 3 . The polyiodides were measured with ac- and dc-techniques. The electric conductivity of the polyiodides increases with increasing iodine contents (triiodides are insulators, penta- and heptaiodides are bad semiconductors). The magnetic susceptibility doesn't depend on the magnetic field strength and on temperature

  11. Electric and Magnetic Coulomb Potentials in the Deuteron

    Directory of Open Access Journals (Sweden)

    Bernard Schaeffer

    2013-09-01

    Full Text Available After one century of nuclear physics, the underlying fun- damental laws of nuclear physics are still missing. Bohr had found a formula for the H atom and another for the H2 molecule but no equivalent formula exists for the deuteron 2H. The only known Coulomb interaction in a nucleus by the mainstream nuclear physics is the long range repulsion between protons, forgetting that the neutron contains elec- tric charges with no net charge. The neutron is attracted by the proton in a way discovered two millenaries ago by the Greeks. This attraction is equilibrated by the repulsion between the opposite magnetic moments of the proton and of the neutron in the deuteron. The bare application of ge- ometry together with electric and magnetic Coulomb’s in- teractions accounts for the binding energy of the deuteron, without fitting, with only 4 per cent discrepancy, proving the electromagnetic nature of the nuclear energy.

  12. Magnetoresistance effect in a both magnetically and electrically modulated nanostructure

    International Nuclear Information System (INIS)

    Lu, Mao-Wang; Yang, Guo-Jian

    2007-01-01

    We propose a magnetoresistance device in a both magnetically and electrically modulated two-dimensional electron gas, which can be realized experimentally by the deposition, on the top and bottom of a semiconductor heterostructure, of two parallel metallic ferromagnetic strips under an applied voltage. It is shown that a considerable magnetoresistance effect can be achieved in such a device due to the significant transmission difference for electrons through parallel and antiparallel magnetization configurations. It is also shown that the magnetoresistance ratio depends strongly on the applied voltage to the stripe in the device. These interesting properties may provide an alternative scheme to realize magnetoresistance effect in hybrid ferromagnetic/semiconductor nanosystems, and this system may be used as a voltage-tunable magnetoresistance device

  13. Electrically driven magnetic relaxation in multiferroic LuFe2O4

    International Nuclear Information System (INIS)

    Wang Fen; Li Changhui; Zou Tao; Liu Yi; Sun Young

    2010-01-01

    We report the electrical control of magnetization in multiferroic LuFe 2 O 4 by applying short current pulses. The magnitude of the induced magnetization change depends on the pulse width and current density. The voltage variation during the applied current pulses evidences an electric-field-induced breakdown of charge order and excludes the role of Joule heating. This current driven magnetization change can be interpreted with a three-temperature model in which the delocalized electrons accelerate spin relaxation through a strong spin-charge coupling inherent to multiferroicity. The electrically assisted magnetic relaxation provides a new approach for electrical control of magnetization.

  14. Electric and magnetic fields from the viewpoint of customer consulting

    International Nuclear Information System (INIS)

    Roehrenbeck, G.

    1995-01-01

    The question of acceptance of electric and magnetic fields by the individual and public opinion cannot be solved by regulations on standard values and precautionary or safety limit values alone. It is just as much a matter of technology acceptance in general and of the communicative skills of companies and associations. The author, an employee of a power supply company, attempts to point out ways towards a better communication with individuals concerned about electromagnetic fields and provide an understanding of the problems involved in getting their acceptance. (orig./VHE) [de

  15. Motor Integrated Permanent Magnet Gear in a Battery Electrical Vehicle

    DEFF Research Database (Denmark)

    Frandsen, Tommy; Mathe, Laszlo; Berg, Nick Ilsø

    2015-01-01

    This paper presents the physical construction and test results of two new demonstrators of a Motor Integrated Permanent Magnet Gear (MIPMG), which is a second version of an already tested demonstrator. The demonstrators will be used as traction units for a Battery Electrical Vehicle (BEV......) and the background for the specifications are elaborated. Simulated as well as measured results of rotational losses of the first and second version are compared. The efficiency of the new design is investigated and compared to three direct drive motors in a few operating points and the MIPMG v.2 seems superior when...

  16. Table of Nuclear Magnetic Dipole and Electric Quadrupole Moments

    International Nuclear Information System (INIS)

    Stone, N.J.

    2011-04-01

    This Table is a compilation of experimental measurements of static magnetic dipole and electric quadrupole moments of ground states and excited states of atomic nuclei throughout the periodic table. To aid identification of the states, their excitation energy, half-life, spin and parity are given, along with a brief indication of the method and any reference standard used in the particular measurement. The literature search covers the period to late 2010. Many of the entries prior to 1988 follow those in Raghavan P., Atomic and Nuclear Data Tables 42, 189 (1989). (author)

  17. Table of Nuclear Magnetic Dipole and Electric Quadrupole Moments

    International Nuclear Information System (INIS)

    Stone, N.J.

    2014-02-01

    This Table is a compilation of experimental measurements of static magnetic dipole and electric quadrupole moments of ground states and excited states of atomic nuclei throughout the periodic table. To aid identification of the states, their excitation energy, half-life, spin and parity are given, along with a brief indication of the method and any reference standard used in the particular measurement. The literature search covers the period to early 2014. Many of the entries prior to 1988 follow those in Raghavan P., Atomic and Nuclear Data Tables 42, 189 (1989). (author)

  18. Magnetic storm effects in electric power systems and prediction needs

    Science.gov (United States)

    Albertson, V. D.; Kappenman, J. G.

    1979-01-01

    Geomagnetic field fluctuations produce spurious currents in electric power systems. These currents enter and exit through points remote from each other. The fundamental period of these currents is on the order of several minutes which is quasi-dc compared to the normal 60 Hz or 50 Hz power system frequency. Nearly all of the power systems problems caused by the geomagnetically induced currents result from the half-cycle saturation of power transformers due to simultaneous ac and dc excitation. The effects produced in power systems are presented, current research activity is discussed, and magnetic storm prediction needs of the power industry are listed.

  19. Influence of electrical sheet width on dynamic magnetic properties

    CERN Document Server

    Chevalier, T; Cornut, B

    2000-01-01

    Effects of the width of electrical steel sheets on dynamic magnetic properties are investigated by solving diffusion equation on the cross-section of the sheet. Linear and non-linear cases are studied, and are compared with measurement on Epstein frame. For the first one an analytical solution is found, while for the second, a 2D finite element simulation is achieved. The influence of width is highlighted for a width thickness ratio lower than 10. It is shown that the behaviour modification in such cases is conditioned by the excitation signal waveform, amplitude and also frequency.

  20. Simultaneous identification of electric permittivity and magnetic permeability

    International Nuclear Information System (INIS)

    Feng, Hui; Jiang, Daijun; Zou, Jun

    2010-01-01

    In this paper we investigate the simultaneous reconstruction of the electric permittivity and magnetic permeability. The two physical parameters are allowed to be highly discontinuous in the concerned physical domain. The ill-posed inverse problem is formulated into an output least-squares nonlinear minimization with BV-regularization. The regularizing effect and mathematical properties of the regularized system are justified and analysed. A fully discrete Nedelec's edge element method is applied to approximate the regularized nonlinear optimization system, and its convergence is demonstrated

  1. Electrical detection of single magnetic skyrmion at room temperature

    Directory of Open Access Journals (Sweden)

    Riccardo Tomasello

    2017-05-01

    Full Text Available This paper proposes a protocol for the electrical detection of a magnetic skyrmion via the change of the tunneling magnetoresistive (TMR signal in a three-terminal device. This approach combines alternating spin-transfer torque from both spin-filtering (due to a perpendicular polarizer and spin-Hall effect with the TMR signal. Micromagnetic simulations, used to test and verify such working principle, show that there exists a frequency region particularly suitable for this achievement. This result can be at the basis of the design of a TMR based read-out for skyrmion detection, overcoming the difficulties introduced by the thermal drift of the skyrmion once nucleated.

  2. Modeling Instruction in AP Physics C: Mechanics and Electricity and Magnetism

    Science.gov (United States)

    Belcher, Nathan Tillman

    This action research study used data from multiple assessments in Mechanics and Electricity and Magnetism to determine the viability of Modeling Instruction as a pedagogy for students in AP Physics C: Mechanics and Electricity and Magnetism. Modeling Instruction is a guided-inquiry approach to teaching science in which students progress through the Modeling Cycle to develop a fully-constructed model for a scientific concept. AP Physics C: Mechanics and Electricity and Magnetism are calculus-based physics courses, approximately equivalent to first-year calculus-based physics courses at the collegiate level. Using a one-group pretest-posttest design, students were assessed in Mechanics using the Force Concept Inventory, Mechanics Baseline Test, and 2015 AP Physics C: Mechanics Practice Exam. With the same design, students were assessed in Electricity and Magnetism on the Brief Electricity and Magnetism Assessment, Electricity and Magnetism Conceptual Assessment, and 2015 AP Physics C: Electricity and Magnetism Practice Exam. In a one-shot case study design, student scores were collected from the 2017 AP Physics C: Mechanics and Electricity and Magnetism Exams. Students performed moderately well on the assessments in Mechanics and Electricity and Magnetism, demonstrating that Modeling Instruction is a viable pedagogy in AP Physics C: Electricity and Magnetism.

  3. The relationship between anatomically correct electric and magnetic field dosimetry and publishe delectric and magnetic field exposure limits.

    Science.gov (United States)

    Kavet, Robert; Dovan, Thanh; Reilly, J Patrick

    2012-12-01

    Electric and magnetic field exposure limits published by International Commission for Non-Ionizing Radiation Protection and Institute of Electrical and Electronics Engineers are aimed at protection against adverse electrostimulation, which may occur by direct coupling to excitable tissue and, in the case of electric fields, through indirect means associated with surface charge effects (e.g. hair vibration, skin sensations), spark discharge and contact current. For direct coupling, the basic restriction (BR) specifies the not-to-be-exceeded induced electric field. The key results of anatomically based electric and magnetic field dosimetry studies and the relevant characteristics of excitable tissue were first identified. This permitted us to assess the electric and magnetic field exposure levels that induce dose in tissue equal to the basic restrictions, and the relationships of those exposure levels to the limits now in effect. We identify scenarios in which direct coupling of electric fields to peripheral nerve could be a determining factor for electric field limits.

  4. Ba doped Fe3O4 nanocrystals: Magnetic field and temperature tuning dielectric and electrical transport

    Science.gov (United States)

    Dutta, Papia; Mandal, S. K.; Nath, A.

    2018-05-01

    Nanocrystalline BaFe2O4 has been prepared through low temperature pyrophoric reaction method. The structural, dielectric and electrical transport properties of BaFe2O4 are investigated in detail. AC electrical properties have been studied over the wide range of frequencies with applied dc magnetic fields and temperatures. The value of impedance is found to increase with increase in magnetic field attributing the magnetostriction property of the sample. The observed value of magneto-impedance and magnetodielectric is found to ∼32% and ∼33% at room temperature. Nyquist plots have been fitted using resistance-capacitor circuits at different magnetic fields and temperatures showing the dominant role of grain and grain boundaries of the sample. Metal-semiconductor transition ∼403 K has been discussed in terms of delocalized and localized charge carrier.We have estimated activation energy using Arrhenius relation indicating temperature dependent electrical relaxation process in the system. Ac conductivity follow a Jonscher’s single power law indicating the large and small polaronic hopping conduction mechanism in the system.

  5. Thermoelectric power of small polarons in magnetic semiconductors

    International Nuclear Information System (INIS)

    Liu, N.H.; Emin, D.

    1984-01-01

    The thermoelectric power (Seebeck coefficient) α of a small polaron in both ferromagnetic and antiferromagnetic semiconductors and insulators is calculated for the first time. In particular, we obtain the contribution to the Seebeck coefficient arising from exchange interactions between the severely localized carrier (i.e., small polaron) of charge q and the spins of the host lattice. In essence, we study the heat transported along with a carrier. This heat, the Peltier heat, Pi, is related to the Seebeck coefficient by the Kelvin relation: Pi = qTα, where T is the temperature. The heat per carrier is simply the product of the temperature and the change of the entropy of the system when a small polaron is added to it. The magnetic contribution to the Seebeck coefficient is therefore directly related to the change of the magnetic entropy of the system upon introduction of a charge carrier. We explicitly treat the intrasite and intersite exchange interactions between a small polaron and the spins of a spin-1/2 system. These magnetic interactions produce two competing contributions to the Seebeck coefficient. First, adding the carrier tends to provide extra spin freedom (e.g., spin up or spin down of the carrier). This effect augments the entropy of the system, thereby producing a positive contribution to the Peltier heat. Second, however, the additional exchange between the carrier and the sites about it enhances the exchange binding among these sites. This generally reduces the energetically allowable spin configurations. The concomitant reduction of the system's entropy provides a negative contribution to the Peltier heat. At the highest of temperatures, when kT exceeds the intrasite exchange energy, the first effect dominates. Then, the Peltier heat is simply augmented by kT ln2

  6. Heavy metal multilayers for switching of magnetic unit via electrical current without magnetic field, method and applications

    Science.gov (United States)

    Ma, Qinli; Li, Yufan; Chien, Chia-ling

    2018-02-20

    Provided is an electric-current-controllable magnetic unit, including: a substrate, an electric-current channel disposed on the substrate, the electric-current channel including a composite heavy-metal multilayer comprising at least one heavy-metal; a capping layer disposed over the electric-current channel; and at least one ferromagnetic layer disposed between the electric-current channel and the capping layer.

  7. Small-scale electrical resistivity tomography of wet fractured rocks.

    Science.gov (United States)

    LaBrecque, Douglas J; Sharpe, Roger; Wood, Thomas; Heath, Gail

    2004-01-01

    This paper describes a series of experiments that tested the ability of the electrical resistivity tomography (ERT) method to locate correctly wet and dry fractures in a meso-scale model. The goal was to develop a method of monitoring the flow of water through a fractured rock matrix. The model was a four by six array of limestone blocks equipped with 28 stainless steel electrodes. Dry fractures were created by placing pieces of vinyl between one or more blocks. Wet fractures were created by injecting tap water into a joint between blocks. In electrical terms, the dry fractures are resistive and the wet fractures are conductive. The quantities measured by the ERT system are current and voltage around the outside edge of the model. The raw ERT data were translated to resistivity values inside the model using a three-dimensional Occam's inversion routine. This routine was one of the key components of ERT being tested. The model presented several challenges. First, the resistivity of both the blocks and the joints was highly variable. Second, the resistive targets introduced extreme changes the software could not precisely quantify. Third, the abrupt changes inherent in a fracture system were contrary to the smoothly varying changes expected by the Occam's inversion routine. Fourth, the response of the conductive fractures was small compared to the background variability. In general, ERT was able to locate correctly resistive fractures. Problems occurred, however, when the resistive fracture was near the edges of the model or when multiple fractures were close together. In particular, ERT tended to position the fracture closer to the model center than its true location. Conductive fractures yielded much smaller responses than the resistive case. A difference-inversion method was able to correctly locate these targets.

  8. Effects of magnetic correlation on the electric properties in multiferroic materials

    International Nuclear Information System (INIS)

    Zhai, Liang-Jun; Wang, Huai-Yu

    2015-01-01

    The effects of magnetic correlation on the electric properties in the multiferroic materials are studied, where the phase transition temperature of the magnetic subsystem T m is lower than that of the electric subsystem T e . A Heisenberg-type Hamiltonian and a transverse Ising model are employed to describe the ferromagnetic and ferroelectric subsystems, respectively. We find that the magnetic correlation can influence the electric properties above the T m , and magnetic transverse and longitudinal correlations have opposite functions. In the curves of temperature dependence of polarization, kinks appear at T m which is dominated by the sharp change of decreasing rate of the magnetic correlation. The kinks can be eliminated by an external magnetic field. The magnetic transverse and longitudinal correlations play contrary roles on the manipulation of polarization by the external magnetic field. - Highlights: • Both magnetic longitudinal and transverse correlations can influence the electric subsystem through magnetoelectric (ME) coupling at any temperature. • The magnetic longitudinal and transverse correlations have contrary effects in influencing the phase transition temperature of electric subsystem. • The electric phase transition temperature decrease with the ME coupling strength, while it was not so by mean-field theory. • An external field can make the influence smoother around the transition point, and can enhance the electric polarization. • Magnetic longitudinal and transverse correlations have contrary effects on the manipulation of polarization by magnetic field at temperature above the magnetic phase transition point

  9. The Gravity and Extreme Magnetism Small Explorer (GEMS)

    Science.gov (United States)

    Kallman, T. R.

    2011-01-01

    The Gravity and Extreme Magnetism Small Explorer (GEMS) was selected by NASA for flight in 2014 to make a sensitive search for X-ray polarization from a wide set of source classes, including stellar black holes, Seyfert galaxies and quasars, blazars, rotation and accretion-powered pulsars, magnetars, shell supernova remnants and pulsar wind nebulae. Among the primary scientific objectives are determining the effects of the spin of black holes and the geometry of supermassive black hole accretion, determining the configurations of the magnetic fields and the X-ray emission of magnetars, and determining the magnetic structure of the supernova shocks in which cosmic rays are accelerated. GEMS will observe 23 targets during a 16 month prime mission, in observations that will be able to reach predicted levels of polarization. The mission can be extended to provide a guest observer phase. The GEMS instrument has time projection chamber polarimeters with high 2-10 keV efficiency at the focus of thin foil mirrors. The 4.5 m focal length mirrors will be deployed on an extended boom. The spacecraft with the instrument is rotated with a period of about 10 minutes to enable measurement and correction of systematic errors. A small Bragg reflection soft X-ray experiment takes advantage of this rotation to obtain a measurement at 0.5 keV. The design of the GEMS instrument and the mission, the expected performance and the planned science program will be discussed.

  10. Electrical polarization and orbital magnetization: the modern theories

    International Nuclear Information System (INIS)

    Resta, Raffaele

    2010-01-01

    Macroscopic polarization P and magnetization M are the most fundamental concepts in any phenomenological description of condensed media. They are intensive vector quantities that intuitively carry the meaning of dipole per unit volume. But for many years both P and the orbital term in M evaded even a precise microscopic definition, and severely challenged quantum-mechanical calculations. If one reasons in terms of a finite sample, the electric (magnetic) dipole is affected in an extensive way by charges (currents) at the sample boundary, due to the presence of the unbounded position operator in the dipole definitions. Therefore P and the orbital term in M-phenomenologically known as bulk properties-apparently behave as surface properties; only spin magnetization is problemless. The field has undergone a genuine revolution since the early 1990s. Contrary to a widespread incorrect belief, P has nothing to do with the periodic charge distribution of the polarized crystal: the former is essentially a property of the phase of the electronic wavefunction, while the latter is a property of its modulus. Analogously, the orbital term in M has nothing to do with the periodic current distribution in the magnetized crystal. The modern theory of polarization, based on a Berry phase, started in the early 1990s and is now implemented in most first-principle electronic structure codes. The analogous theory for orbital magnetization started in 2005 and is partly work in progress. In the electrical case, calculations have concerned various phenomena (ferroelectricity, piezoelectricity, and lattice dynamics) in several materials, and are in spectacular agreement with experiments; they have provided thorough understanding of the behaviour of ferroelectric and piezoelectric materials. In the magnetic case the very first calculations are appearing at the time of writing (2010). Here I review both theories on a uniform ground in a density functional theory (DFT) framework, pointing out

  11. Sensitivity analysis of magnetic field measurements for magnetic resonance electrical impedance tomography (MREIT)

    DEFF Research Database (Denmark)

    Göksu, Cihan; Scheffler, Klaus; Ehses, Philipp

    2017-01-01

    Purpose: Clinical use of magnetic resonance electrical impedance tomography (MREIT) still requires significant sensitivity improvements. Here, the measurement of the current-induced magnetic field (DBz,c) is improved using systematic efficiency analyses and optimization of multi-echo spin echo...... (MESE) and steady-state free precession free induction decay (SSFP-FID) sequences. Theory and Methods: Considering T1, T2, and T 2 relaxation in the signal-to-noise ratios (SNRs) of the MR magnitude images, the efficiency of MESE and SSFP-FID MREIT experiments, and its dependence on the sequence...

  12. Electrically and magnetically dual-driven Janus particles for handwriting-enabled electronic paper

    Energy Technology Data Exchange (ETDEWEB)

    Komazaki, Y., E-mail: komazaki@dt.k.u-tokyo.ac.jp; Hirama, H.; Torii, T. [Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8563 (Japan)

    2015-04-21

    In this work, we describe the synthesis of novel electrically and magnetically dual-driven Janus particles for a handwriting-enabled twisting ball display via the microfluidic technique. One hemisphere of the Janus particles contains a charge control agent, which allows the display color to be controlled by applying a voltage and superparamagnetic nanoparticles, allows handwriting by applying a magnetic field to the display. We fabricated a twisting ball display utilizing these Janus particles and tested the electric color control and handwriting using a magnet. As a result, the display was capable of permitting handwriting with a small magnet in addition to conventional color control using an applied voltage (80 V). Handwriting performance was improved by increasing the concentration of superparamagnetic nanoparticles and was determined to be possible even when 80 V was applied across the electrodes for 4 wt. % superparamagnetic nanoparticles in one hemisphere. This improvement was impossible when the concentration was reduced to 2 wt. % superparamagnetic nanoparticles. The technology presented in our work can be applied to low-cost, lightweight, highly visible, and energy-saving electronic message boards and large whiteboards because the large-size display can be fabricated easily due to its simple structure.

  13. Electrically and magnetically dual-driven Janus particles for handwriting-enabled electronic paper

    International Nuclear Information System (INIS)

    Komazaki, Y.; Hirama, H.; Torii, T.

    2015-01-01

    In this work, we describe the synthesis of novel electrically and magnetically dual-driven Janus particles for a handwriting-enabled twisting ball display via the microfluidic technique. One hemisphere of the Janus particles contains a charge control agent, which allows the display color to be controlled by applying a voltage and superparamagnetic nanoparticles, allows handwriting by applying a magnetic field to the display. We fabricated a twisting ball display utilizing these Janus particles and tested the electric color control and handwriting using a magnet. As a result, the display was capable of permitting handwriting with a small magnet in addition to conventional color control using an applied voltage (80 V). Handwriting performance was improved by increasing the concentration of superparamagnetic nanoparticles and was determined to be possible even when 80 V was applied across the electrodes for 4 wt. % superparamagnetic nanoparticles in one hemisphere. This improvement was impossible when the concentration was reduced to 2 wt. % superparamagnetic nanoparticles. The technology presented in our work can be applied to low-cost, lightweight, highly visible, and energy-saving electronic message boards and large whiteboards because the large-size display can be fabricated easily due to its simple structure

  14. Electrical and Magnetic Properties of Binary Amorphous Transition Metal Alloys.

    Science.gov (United States)

    Liou, Sy-Hwang

    The electrical, superconductive and magnetic properties of several binary transition metal amorphous and metastable crystalline alloys, Fe(,x)Ti(,100-x) (30 (LESSTHEQ) x (LESSTHEQ) 100), Fe(,x)Zr(,100-x) (20 (LESSTHEQ) x (LESSTHEQ) 93), Fe(,x)Hf(,100-x) (20 (LESSTHEQ) x (LESSTHEQ) 100), Fe(,x)Nb(,100 -x) (22 (LESSTHEQ) x (LESSTHEQ) 85), Ni(,x)Nb(,100-x) (20 (LESSTHEQ) x (LESSTHEQ) 80), Cu(,x)Nb(,100-x) (10 (LESSTHEQ) x (LESSTHEQ) 90) were studied over a wide composition range. Films were made using a magnetron sputtering system, and the structure of the films was investigated by energy dispersive x-ray diffraction. The composition region of each amorphous alloys system was determined and found in good agreement with a model proposed by Egami and Waseda. The magnetic properties and hyperfine interactions in the films were investigated using a conventional Mossbauer spectrometer and a ('57)Co in Rh matrix source. In all Fe-early transition metal binary alloys systems, Fe does not retain its moment in the low iron concentration region and the result is that the critical concentration for magnetic order (x(,c)) is much larger than anticipated from percolation considerations. A direct comparison between crystalline alloys and their amorphous counterparts of the same composition illustrate no clear correlation between crystalline and amorphous states. Pronounced discontinuities in the magnetic properties with variation in Fe content of all Fe-early transition metal alloys at phase boundaries separating amorphous and crystalline states have been observed. This is caused by the differences in the atomic arrangement and the electronic structure between crystalline and amorphous solids. The temperature dependence of resistivity, (rho)(T), of several binary amorphous alloys of Fe-TM (where TM = Ti, Zr, Hf, Nb etc.) has been studied from 2K to 300K. The Fe-poor (x x(,c)) samples have distinctive differences in (rho)(T) at low temperature (below 30K). All the magnetic samples

  15. Longitudinal study of student conceptual understanding in electricity and magnetism

    Directory of Open Access Journals (Sweden)

    S. J. Pollock

    2009-12-01

    Full Text Available We have investigated the long-term effect of student-centered instruction at the freshman level on juniors’ performance on a conceptual survey of Electricity and Magnetism (E&M. We measured student performance on a research-based conceptual instrument—the Brief Electricity & Magnetism Assessment (BEMA–over a period of 8 semesters (2004–2007. Concurrently, we introduced the University of Washington's Tutorials in Introductory Physics as part of our standard freshman curriculum. Freshmen took the BEMA before and after this Tutorial-based introductory course, and juniors took it after completion of their traditional junior-level E&M I and E&M II courses. We find that, on average, individual BEMA scores do not change significantly after completion of the introductory course—neither from the freshman to the junior year, nor from upper-division E&M I to E&M II. However, we find that juniors who had completed a non-Tutorial freshman course scored significantly lower on the (post-upper-division BEMA than those who had completed the reformed freshman course—indicating a long-term positive impact of freshman Tutorials on conceptual understanding.

  16. Measurement of magnetic and electric field inhomogenities in a time projection chamber using laser tracks

    International Nuclear Information System (INIS)

    Benetta, M.; Froberger, J.P.; Lehraus, I.; Mathewson, R.; May, J.; Price, M.; Schlater, D.; Tejessi, W.; Witzeling, W.

    1985-01-01

    The large time projection chambers (TPC) for particle track measurements have their electric drift field parallel to the magnetic field which is needed for the momentum measurement of the particles. Small field inhomogeneities of the order of epsilon times the main field cause large track distortions (coordinate displacements) of the order of epsilon times the driftlength. It is therefore important for every TPC to know the inhomogeneities very well. Laser rays have proven to be useful to study them. We report here on our experience with a TPC having a maximum drift length of 1.3 m

  17. Magnetic resonance electrical impedance tomography for measuring electrical conductivity during electroporation

    International Nuclear Information System (INIS)

    Kranjc, M; Miklavčič, D; Bajd, F; Serša, I

    2014-01-01

    The electroporation effect on tissue can be assessed by measurement of electrical properties of the tissue undergoing electroporation. The most prominent techniques for measuring electrical properties of electroporated tissues have been voltage–current measurement of applied pulses and electrical impedance tomography (EIT). However, the electrical conductivity of tissue assessed by means of voltage–current measurement was lacking in information on tissue heterogeneity, while EIT requires numerous additional electrodes and produces results with low spatial resolution and high noise. Magnetic resonance EIT (MREIT) is similar to EIT, as it is also used for reconstruction of conductivity images, though voltage and current measurements are not limited to the boundaries in MREIT, hence it yields conductivity images with better spatial resolution. The aim of this study was to investigate and demonstrate the feasibility of the MREIT technique for assessment of conductivity images of tissues undergoing electroporation. Two objects were investigated: agar phantoms and ex vivo liver tissue. As expected, no significant change of electrical conductivity was detected in agar phantoms exposed to pulses of all used amplitudes, while a considerable increase of conductivity was measured in liver tissue exposed to pulses of different amplitudes. (paper)

  18. Use of a magnetic force exciter to vibrate a piezocomposite generating element in a small-scale windmill

    International Nuclear Information System (INIS)

    Luong, Hung Truyen; Goo, Nam Seo

    2012-01-01

    A piezocomposite generating element (PCGE) can be used to convert ambient vibrations into electrical energy that can be stored and used to power other devices. This paper introduces a design of a magnetic force exciter for a small-scale windmill that vibrates a PCGE to convert wind energy into electrical energy. A small-scale windmill was designed to be sensitive to low-speed wind in urban regions for the purpose of collecting wind energy. The magnetic force exciter consists of exciting magnets attached to the device’s input rotor and a secondary magnet fixed at the tip of the PCGE. The PCGE is fixed to a clamp that can be adjusted to slide on the windmill’s frame in order to change the gap between exciting and secondary magnets. Under an applied wind force, the input rotor rotates to create a magnetic force interaction that excites the PCGE. The deformation of the PCGE enables it to generate electric power. Experiments were performed with different numbers of exciting magnets and different gaps between the exciting and secondary magnets to determine the optimal configuration for generating the peak voltage and harvesting the maximum wind energy for the same range of wind speeds. In a battery-charging test, the charging time for a 40 mA h battery was approximately 3 h for natural wind in an urban region. The experimental results show that the prototype can harvest energy in urban regions with low wind speeds and convert the wasted wind energy into electricity for city use. (paper)

  19. Low-frequency transient electric and magnetic fields coupling to child body

    International Nuclear Information System (INIS)

    Ozen, S.

    2008-01-01

    Much of the research related to residential electric and magnetic field exposure focuses on cancer risk for children. But until now only little knowledge about coupling of external transient electric and magnetic fields with the child's body at low frequency transients existed. In this study, current densities, in the frequency range from 50 Hz up to 100 kHz, induced by external electric and magnetic fields to child and adult human body, were investigated, as in residential areas, electric and magnetic fields become denser in this frequency band. For the calculations of induced fields and current density, the ellipsoidal body models are used. Current density induced by the external magnetic field (1 μT) and external electric field (1 V/m) is estimated. The results of this study show that the transient electric and magnetic fields would induce higher current density in the child body than power frequency fields with similar field strength. (authors)

  20. Magnetic and velocity fields in a dynamo operating at extremely small Ekman and magnetic Prandtl numbers

    Science.gov (United States)

    Šimkanin, Ján; Kyselica, Juraj

    2017-12-01

    Numerical simulations of the geodynamo are becoming more realistic because of advances in computer technology. Here, the geodynamo model is investigated numerically at the extremely low Ekman and magnetic Prandtl numbers using the PARODY dynamo code. These parameters are more realistic than those used in previous numerical studies of the geodynamo. Our model is based on the Boussinesq approximation and the temperature gradient between upper and lower boundaries is a source of convection. This study attempts to answer the question how realistic the geodynamo models are. Numerical results show that our dynamo belongs to the strong-field dynamos. The generated magnetic field is dipolar and large-scale while convection is small-scale and sheet-like flows (plumes) are preferred to a columnar convection. Scales of magnetic and velocity fields are separated, which enables hydromagnetic dynamos to maintain the magnetic field at the low magnetic Prandtl numbers. The inner core rotation rate is lower than that in previous geodynamo models. On the other hand, dimensional magnitudes of velocity and magnetic fields and those of the magnetic and viscous dissipation are larger than those expected in the Earth's core due to our parameter range chosen.

  1. Electric susceptibility of a magnetized plasma under electromagnetically induced transparency

    International Nuclear Information System (INIS)

    Kawamori, E

    2011-01-01

    This study derives the electric susceptibility tensor of a cold magnetized plasma under electromagnetically induced transparency (EIT) regime (Litvak and Tokman 2002 Phys. Rev. Lett. 88 095003, Shvets and Wurtele 2002 Phys. Rev. Lett. 89 115003) in which an intense right-hand circularly polarized pump wave is injected parallel to the background magnetic field. A dispersion relation of the wave in the electron cyclotron frequency range for an arbitrary propagation angle is obtained from this susceptibility tensor. In the case of purely parallel propagation of the probe wave, the dispersion relation obtained by Litvak, Shvets and others is recaptured. A new finding is that a stop band emerges between left-hand cutoff and upper hybrid frequencies, in which originally an extraordinary-mode (X) branch exists, in the case of perpendicular propagation to the background magnetic field under the EIT. The bandwidth of the stop band expands as the pump wave is intensified. For the situation of launching the probe wave from the high-field side in a tokamak, the accessibility of the probe wave to the region where the EIT effect appears is investigated. The EIT region which is a resonance layer created by the EIT is accessible to the probe wave, indicating the possibility of the application of EIT to control the spatial position of wave power deposition.

  2. Electric field tuning of magnetism in heterostructure of yttrium iron garnet film/lead magnesium niobate-lead zirconate titanate ceramic

    Science.gov (United States)

    Lian, Jianyun; Ponchel, Freddy; Tiercelin, Nicolas; Chen, Ying; Rémiens, Denis; Lasri, Tuami; Wang, Genshui; Pernod, Philippe; Zhang, Wenbin; Dong, Xianlin

    2018-04-01

    In this paper, the converse magnetoelectric (CME) effect by electric field tuning of magnetization in an original heterostructure composed of a polycrystalline yttrium iron garnet (YIG) film and a lead magnesium niobate-lead zirconate titanate (PMN-PZT) ceramic is presented. The magnetic performances of the YIG films with different thicknesses under a DC electric field applied to the PMN-PZT ceramics and a bias magnetic field are investigated. All the magnetization-electric field curves are found to be in good agreement with the butterfly like strain curve of the PMN-PZT ceramic. Both the sharp deformation of about 2.5‰ of PMN-PZT and the easy magnetization switching of YIG are proposed to be the reasons for the strongest CME interaction in the composite at the small electric coercive field of PMN-PZT (4.1 kV/cm) and the small magnetic coercive field of YIG (20 Oe) where the magnetic susceptibility reaches its maximum value. A remarkable CME coefficient of 3.1 × 10-7 s/m is obtained in the system with a 600 nm-thick YIG film. This heterostructure combining multiferroics and partially magnetized ferrite concepts is able to operate under a small or even in the absence of an external bias magnetic field and is more compact and power efficient than the traditional magnetoelectric devices.

  3. Research procedure for buck-boost converter for small electric vehicles

    Science.gov (United States)

    Vacheva, Gergana; Hinov, Nikolay; Penev, Dimitar

    2017-12-01

    In the current paper is developed a mathematical model realized in Matlab for describing a buck-boost converter for control of small electric vehicle. The model is presented with differential equations which describes the processes in the converter. Through the research of this model it can be accomplished the optimal work mode of a small electric vehicles. The proposed converter can be used in a wide range of applications like small electric vehicles, smart grids and different systems for energy storage.

  4. Dynamically fluctuating electric dipole moments in fullerene-based magnets.

    Science.gov (United States)

    Kambe, Takashi; Oshima, Kokichi

    2014-09-19

    We report here the direct evidence of the existence of a permanent electric dipole moment in both crystal phases of a fullerene-based magnet--the ferromagnetic α-phase and the antiferromagnetic α'-phase of tetra-kis-(dimethylamino)-ethylene-C60 (TDAE-C60)--as determined by dielectric measurements. We propose that the permanent electric dipole originates from the pairing of a TDAE molecule with surrounding C60 molecules. The two polymorphs exhibit clear differences in their dielectric responses at room temperature and during the freezing process with dynamically fluctuating electric dipole moments, although no difference in their room-temperature structures has been previously observed. This result implies that two polymorphs have different local environment around the molecules. In particular, the ferromagnetism of the α-phase is founded on the homogeneous molecule displacement and orientational ordering. The formation of the different phases with respect to the different rotational states in the Jahn-Teller distorted C60s is also discussed.

  5. ELECTROMAGNETIC SAFETY OF ELECTRIC TRANSPORT SYSTEMS: MAIN SOURCES AND PARAMETERS OF MAGNETIC FIELDS

    Directory of Open Access Journals (Sweden)

    N. G. Ptitsyna

    2013-03-01

    Full Text Available Magnetic fields produced by electric drive vehicles may break electromagnetic safety. For electromagnetic safety and electromagnetic compatibility knowledge about characteristics and sources of magnetic fields in the electric transport is necessary. The article deals with analysis of available data about magnetic fields in electric cars and comparison with results of our measurements carried out in the other types of electrified transport systems.

  6. SMALL-SCALE MAGNETIC ISLANDS IN THE SOLAR WIND AND THEIR ROLE IN PARTICLE ACCELERATION. I. DYNAMICS OF MAGNETIC ISLANDS NEAR THE HELIOSPHERIC CURRENT SHEET

    Energy Technology Data Exchange (ETDEWEB)

    Khabarova, O. [Heliophysical Laboratory, Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radiowave Propagation RAS (IZMIRAN), Troitsk, Moscow 142190 (Russian Federation); Zank, G. P.; Li, G.; Roux, J. A. le; Webb, G. M.; Dosch, A. [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35805 (United States); Malandraki, O. E. [IAASARS, National Observatory of Athens, GR-15236 Penteli (Greece)

    2015-08-01

    Increases of ion fluxes in the keV–MeV range are sometimes observed near the heliospheric current sheet (HCS) during periods when other sources are absent. These resemble solar energetic particle events, but the events are weaker and apparently local. Conventional explanations based on either shock acceleration of charged particles or particle acceleration due to magnetic reconnection at interplanetary current sheets (CSs) are not persuasive. We suggest instead that recurrent magnetic reconnection occurs at the HCS and smaller CSs in the solar wind, a consequence of which is particle energization by the dynamically evolving secondary CSs and magnetic islands. The effectiveness of the trapping and acceleration process associated with magnetic islands depends in part on the topology of the HCS. We show that the HCS possesses ripples superimposed on the large-scale flat or wavy structure. We conjecture that the ripples can efficiently confine plasma and provide tokamak-like conditions that are favorable for the appearance of small-scale magnetic islands that merge and/or contract. Particles trapped in the vicinity of merging islands and experiencing multiple small-scale reconnection events are accelerated by the induced electric field and experience first-order Fermi acceleration in contracting magnetic islands according to the transport theory of Zank et al. We present multi-spacecraft observations of magnetic island merging and particle energization in the absence of other sources, providing support for theory and simulations that show particle energization by reconnection related processes of magnetic island merging and contraction.

  7. Mapping and quantifying electric and magnetic dipole luminescence at the nanoscale.

    Science.gov (United States)

    Aigouy, L; Cazé, A; Gredin, P; Mortier, M; Carminati, R

    2014-08-15

    We report on an experimental technique to quantify the relative importance of electric and magnetic dipole luminescence from a single nanosource in structured environments. By attaching a Eu^{3+}-doped nanocrystal to a near-field scanning optical microscope tip, we map the branching ratios associated with two electric dipole and one magnetic dipole transitions in three dimensions on a gold stripe. The relative weights of the electric and magnetic radiative local density of states can be recovered quantitatively, based on a multilevel model. This paves the way towards the full electric and magnetic characterization of nanostructures for the control of single emitter luminescence.

  8. submitter A High Precision 3D Magnetic Field Scanner for Small to Medium Size Magnets

    CERN Document Server

    Bergsma, F; Garnier, F; Giudici, P A

    2016-01-01

    A bench to measure the magnetic field of small to-medium-sized magnets with high precision was built. It uses a small-sized head with three orthogonal Hall probes, supported on a long pole at continuous movement during measurement. The head is calibrated in three dimensions by rotation over the full solid angle in a special device. From 0 to 2.5 T, the precision is ±0.2 mT in all components. The spatial range is 1 × 1 × 2 m with precision of ±0.02 mm. The bench and its controls are lightweight and easy to transport. The head can penetrate through small apertures and measure as close as 0.5 mm from the surface of a magnet. The bench can scan complicated grids in Cartesian or cylindrical coordinates, steered by a simple text file on an accompanying PC. The raw data is online converted to magnetic units and stored in a text file.

  9. Magnetic and Electrical Transport Properties of Dirac Compound BaMnSb2*

    Science.gov (United States)

    Huang, Silu; Kim, Jisun; Shelton, William. A.; Plummer, Ward; Jin, Rongying

    BaMnSb2 is a layered compound containing Sb square nets that is theoretically predicted to host Dirac fermions. We have carried out experimental investigations on electrical transport and magnetic properties of BaMnSb2 single crystals. Both in-plane (ρab) and c-axis (ρc) resistivities show metallic behavior with a small bump in ρc located near 40 K, while there is large anisotropy ρc / ρab ( 100 at 300 K) that increases with decreasing temperature to 1500 at 2 K. Interestingly, Shubnikov-de Hass (SdH) oscillations are observed for both ρab and ρc over a wide temperature and magnetic field range. Quantitative analysis indicates that large amplitude SdH oscillations result from nearly massless Dirac Fermions. Furthermore, our magnetic measurements indicate an A-type antiferromagnetic magnetic ordering below 286 K where ferromagnetic ordering is observed in the ab plane with antiferromagnetic coupling along the c direction. These results indicate that BaMnSb2 is a 2D magnetic Dirac material. This work is supported by NSF through Grant Number DMR-1504226.

  10. Power converter with maximum power point tracking MPPT for small wind-electric pumping systems

    International Nuclear Information System (INIS)

    Lara, David; Merino, Gabriel; Salazar, Lautaro

    2015-01-01

    Highlights: • We implement a wind electric pumping system of small power. • The power converter allowed to change the operating point of the electro pump. • Two control techniques were implemented in the power converter. • The control V/f variable allowed to increase the power generated by the permanent magnet generator. - Abstract: In this work, an AC–DC–AC direct-drive power converter was implemented for a wind electric pumping system consisting of a permanent magnet generator (PMG) of 1.3 kW and a peripheral single phase pump of 0.74 kW. In addition, the inverter linear V/f control scheme and the maximum power point tracking (MPPT) algorithm with variable V/f were developed. MPPT algorithm seeks to extract water in a wide range of power input using the maximum amount of wind power available. Experimental trials at different pump pressures were conducted. With a MPPT tracking system with variable V/f, a power value of 1.3 kW was obtained at a speed of 350 rpm and a maximum operating hydraulic head of 50 m. At lower operating heads pressures (between 10 and 40 m), variable V/f control increases the power generated by the PMG compared to the linear V/f control. This increase ranged between 4% and 23% depending on the operating pressure, with an average of 13%, getting close to the maximum electrical power curve of the PMG. The pump was driven at variable frequency reaching a minimum speed of 0.5 times the rated speed. Efficiency of the power converter ranges between 70% and 95% with a power factor between 0.4 and 0.85, depending on the operating pressure

  11. Electrical and magnetic transport in Strontium doped Europium Ferrimanganites

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Latif, I.A. [Physics Department, College of Science & Arts, Najran University, P. O. 1988, Najran (Saudi Arabia); Reactor Physics Department, NRC, Atomic Energy Authority, Abou Zabaal P.O. 13759, Cairo (Egypt); Ahmed, Mahrous R. [Physics Department, Faculty of Science, Sohag University, Sohag 82524 (Egypt); Physics Department, Aljamoum University College, Um-Elqura University, Makka (Saudi Arabia); Al-Omari, I.A.; Sellai, A. [Physics Department, Faculty of Science, Soltan Qaboos University, P.O. Box 36, PC 123, Muscatt (Oman)

    2016-12-15

    Eu{sub 0.65}Sr{sub 0.35}Fe{sub x}Mn{sub 1−x}O{sub 3} (x=0.1, 0.3 and 0.5) has been prepared using a standard solid state reaction method. The under-investigation compounds is found to crystallize in a single-phase orthorhombic structure in the P{sub bnm} space group (62). The adiabatic polaron electronic transfer was obtained for all samples and the activation energy of x=0.1 sample is equal to 1.013 meV and slightly increase at x=0.3 (1.289 meV) while is doubled for x=0.5 to be 2.1065 meV. The magnetization–temperature dependence measurements of Eu{sub 0.65}Sr{sub 0.35}Fe{sub x}Mn{sub 1−x}O{sub 3} show the ferromagnetic ordering at low iron concentration x=0.1 and when iron concentration increase to x=0.5 the noncollinear magnetic ordering (the canted antiferromagnetic) is obtained. The magnetic phase transition (paramagnetic-ferromagnetic transition) in the Eu{sub 0.65}Sr{sub 0.35}Fe{sub 0.1}Mn{sub 0.9}O{sub 3} is observed at T{sub c} of 150 K. For Eu{sub 0.65}Sr{sub 0.35}Fe{sub 0.5}Mn{sub 0.5}O{sub 3} the multi-magnetic phase transition is observed at T{sub c} of 200K and T{sub N} of 430 K. The resistivity at low temperature is measured. Theoretical Calculations using Monte Carlo code have been done. The magnetization as function of temperature has been calculated using Monte Carlo simulations for Eu{sub 0.65}Sr{sub 0.35}Fe{sub x}Mn{sub 1−x}O{sub 3} (x=0.0, 0.1, 0,2, 0.3, 0.4 and 0.5). Ising model is a suitable model to study the magnetization for our compounds. The internal energy for x=0 is the highest value compared with the other x values which have nearly a ground state value equal to 2.7 J. - Highlights: • The distortion parameter in the crystal structure of Eu{sub 0.65}Sr{sub 0.35}Fe{sub x}Mn{sub 1−x}O{sub 3} increase with increasing concentration of iron and affected both electrical and magnetic transport. • The density of electrons over the unit cell decrease with increasing the iron concentration and thus give rise to the decrease in

  12. Magnetic field influence on substructure formed by electric spark treatment

    International Nuclear Information System (INIS)

    Reza Rahbari, G.; Ivanov, A.N.

    1996-01-01

    The substructure of surface layer (about 10 microns thick) has been studied by x-ray line broadening technique in the samples of plain carbon steel (0.45%C) after electric spark doping with and without magnetic field (MF). The applied spark pulse energy was 0.12 J and MF induction varied from 0 to 0.08 T. The electrode material was the same as that of the treated sample. It has been observed that the MF reduces the tensile residual surface stresses from 660 ± 15MPa (no MF) to 260 ± 15MPa (B=0.053 T). The analysis of x-ray line broadening has revealed only the existence of microstrains, which are dependent of the MF magnitude. The microstrains have been related to the randomly distributed dislocation with the density of about 3x10 sup 11 cm sup -2

  13. Prediction of compounds with electric and magnetic ordering

    Energy Technology Data Exchange (ETDEWEB)

    Nikiforov, L G [Rybinskij Aviatsionnyj Tekhnologicheskij Inst. (USSR)

    1979-03-01

    The possibility of polymorphic transformations from the structure of the pyrochlore type into that of the perovskite type for nine lead-containing compounds has been forecast. Some of them (PbTaO/sub 3/, Pb/sub 2/NiTaO/sub 6/, Pb/sub 2/MnTaO/sub 6/, Pb/sub 2/SmTaO/sub 6/) are expected to have, in addition to common for all lead-containing perovskites ferro-or antiferro-electric properties, specific magnetic properties. The periods of elementary cells of new perovskites are forecast. The possibility of considerable reduction of the number of errors when searching thermodynamical parameters of transformation has been shown.

  14. Electric and Magnetic Dipole Strength at Low Energy

    Science.gov (United States)

    Sieja, K.

    2017-08-01

    A low-energy enhancement of radiative strength functions was deduced from recent experiments in several mass regions of nuclei, which is believed to impact considerably the calculated neutron capture rates. In this Letter we investigate the behavior of the low-energy γ -ray strength of the Sc 44 isotope, for the first time taking into account both electric and magnetic dipole contributions obtained coherently in the same theoretical approach. The calculations are performed using the large-scale shell-model framework in a full 1 ℏω s d -p f -g d s model space. Our results corroborate previous theoretical findings for the low-energy enhancement of the M 1 strength but show quite different behavior for the E 1 strength.

  15. Magnetic properties in MnBi alloy of small crystallites for permanent magnet devices

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, S. K.; Prakash, H. R.; Ram, S., E-mail: jms.sanjeev@gmail.com [Materials Science Centre, Indian Institute of Technology, Kharagpur-721302 (India)

    2016-05-06

    A rare-earth free alloy like MnBi is a potential candidate for developing small magnets and devices. In a commercially viable method, a MnBi alloy was prepared by arc melting Mn and Bi metals in a 1:1 ratio. In terms of the X-ray diffraction a single crystalline MnBi phase is formed of the as prepared alloy. FESEM images delineate thin MnBi layers (25 – 40 nm thickness) of average EDX composition throughout the specimen. A large coercivity 5.501 kOe (6.5 emu/g magnetization) observed in an M-H at 300 K is decreased to 0.171 (9.0 emu/g magnetization) at 100 K in decreasing upon cooling.

  16. Metrology in electricity and magnetism: EURAMET activities today and tomorrow

    Science.gov (United States)

    Piquemal, F.; Jeckelmann, B.; Callegaro, L.; Hällström, J.; Janssen, T. J. B. M.; Melcher, J.; Rietveld, G.; Siegner, U.; Wright, P.; Zeier, M.

    2017-10-01

    Metrology dedicated to electricity and magnetism has changed considerably in recent years. It encompasses almost all modern scientific, industrial, and societal challenges, e.g. the revision of the International System of Units, the profound transformation of industry, changes in energy use and generation, health, and environment, as well as nanotechnologies (including graphene and 2D materials) and quantum engineering. Over the same period, driven by the globalization of worldwide trade, the Mutual Recognition Arrangement (referred to as the CIPM MRA) was set up. As a result, the regional metrology organizations (RMOs) of national metrology institutes have grown in significance. EURAMET is the European RMO and has been very prominent in developing a strategic research agenda (SRA) and has established a comprehensive research programme. This paper reviews the highlights of EURAMET in electrical metrology within the European Metrology Research Programme and its main contributions to the CIPM MRA. In 2012 EURAMET undertook an extensive roadmapping exercise for proposed activities for the next decade which will also be discussed in this paper. This work has resulted in a new SRA of the second largest European funding programme: European Metrology Programme for Innovation and Research.

  17. High voltage diagnostics on electrical insulation of supersonducting magnets

    International Nuclear Information System (INIS)

    Irmisch, M.

    1995-12-01

    The high voltage (HV) performance of superconducting magnets of large dimensions, e.g. as needed in fusion reactors, is a challange in the field of high voltage technology, i.e. especially in the field of cryogenic high voltage components and with respect to questions of HV insulation diagnostics at low temperature. By using the development of POLO - a superconducting prototype coil of a tokamak poloidal field coil - as an example, this work deals with special problems of how to get use of conventional HV test techniques for diagnostics under special cryogenic boundary conditions. As a first approach to gain experience in the field of phase resolved partial discharge (PRPD) measurements during operation of a superconductive coil, the POLO coil was subject to several high voltage tests. Compared with DC insulation resistance measurements and capacitive impulse voltage discharges to the coil, the AC PD measurements have been the only way to observe special characteristics of the electrical insulation with respect to the cooling down of the coil from 300 K to 4.2 K. The PRPD measurement technique thereby has proofed as a suitable diagnostic tool. This work can serve as basic data to be comparable within further projects of electrical insulation diagnostics at cryogenic temperatures. (orig.)

  18. Assessment of multiple frequency ELF electric and magnetic field exposure

    International Nuclear Information System (INIS)

    Leitgeb, N

    2008-01-01

    Electromagnetic fields both in daily life and at workplaces exhibit increasingly complex frequency spectra. Present spectral assessment rules proved to be too conservative for health risk assessment. This is because they are based on the assumption that cells would react like linear systems in terms of responding to a sum of frequencies by a sum of independent responses to each individual frequency. Based on numerical investigations with the Hodgkin-Huxley and the Frankenhaeuser-Huxley nerve cell models, it could be shown that accounting for the nonlinear behaviour of cellular excitation processes avoids considerable overestimation of simultaneous exposures to multiple frequency ELF electric and magnetic fields. Besides this, it could be shown that the role of phase relationships is less important than that assumed so far. The present assessment rules lead to non-compliances of marketed electric appliances. For general application, a nonlinear biology-based assessment (NBBA) rule has been proposed, validated and proven advantageous compared with ICNIRP's rule. While staying conservative it avoids unnecessary overestimation and demonstrates compliance even in cases of suspected non-conformities. It is up to responsible bodies to decide upon the adoption of this proposal and the potential need for implementing additional or reducing the already incorporated safety factors

  19. Rotatable Small Permanent Magnet Array for Ultra-Low Field Nuclear Magnetic Resonance Instrumentation: A Concept Study.

    Science.gov (United States)

    Vogel, Michael W; Giorni, Andrea; Vegh, Viktor; Pellicer-Guridi, Ruben; Reutens, David C

    2016-01-01

    We studied the feasibility of generating the variable magnetic fields required for ultra-low field nuclear magnetic resonance relaxometry with dynamically adjustable permanent magnets. Our motivation was to substitute traditional electromagnets by distributed permanent magnets, increasing system portability. The finite element method (COMSOL®) was employed for the numerical study of a small permanent magnet array to calculate achievable magnetic field strength, homogeneity, switching time and magnetic forces. A manually operated prototype was simulated and constructed to validate the numerical approach and to verify the generated magnetic field. A concentric small permanent magnet array can be used to generate strong sample pre-polarisation and variable measurement fields for ultra-low field relaxometry via simple prescribed magnet rotations. Using the array, it is possible to achieve a pre-polarisation field strength above 100 mT and variable measurement fields ranging from 20-50 μT with 200 ppm absolute field homogeneity within a field-of-view of 5 x 5 x 5 cubic centimetres. A dynamic small permanent magnet array can generate multiple highly homogeneous magnetic fields required in ultra-low field nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) instruments. This design can significantly reduce the volume and energy requirements of traditional systems based on electromagnets, improving portability considerably.

  20. Application of permanent magnet BaFe12O19 and NdFeB on small scale low speed permanent magnet generator

    International Nuclear Information System (INIS)

    Pudji Irasari; Novrita Idayanti

    2009-01-01

    Designing and manufacturing of low speed permanent magnet generator (PMG) for small scale electric power plant have been conducted. In this paper, the characteristics of generator using permanent magnet of barium ferrite (BaFe 12 O 19 ) and neodymium iron boron (NdFeB) were compared. Surface mounted type is selected as the rotor structure as all flux faces to stator winding and take a role in energy conversion. The experiment result demonstrates that at nominal speed, generator with BaFe 12 O 19 magnet can only generate power of 8.87 W while generator with NdFeB magnet can generate power of 1,988.93 W. (author)

  1. Probing exotic magnetic phases and electrical transport in Cr-rich γ-NiFeCr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Pampa [S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700098 (India); Majumdar, A.K., E-mail: akm@bose.res.in [S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700098 (India); Ramakrishna Mission Vivekananda University, PO Belur Math, Howrah 711202 (India); Nigam, A.K. [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India)

    2015-05-01

    We have identified ferromagnetic, antiferromagnetic, and re-entrant spin-glass-like phases in Cr-rich γ-NiFeCr alloys and studied their critical magnetic behavior. Their electrical resistivity exhibits distinct minima between 10 and 24 K with ρ∞−√T due to electron–electron interaction effects. Electron–phonon and electron–magnon contributions to ρ are isolated. The magnetoresistance shows hysteresis effects, a signature of spin-glass-like phases and a sign reversal with change of magnetic states. We have also observed that the nature of magnetic states strongly depends on the concentration of Fe and Cr. In this system, even a small amount of Fe enhances ferromagnetism a lot while addition of a little bit of Cr suppresses ferromagnetism and takes the system to the antiferromagnetic regime. The correlation between the magnetic and the electrical properties are more meaningful here since both studies were done on the same set of samples which have rather high melting points. - Highlights: • Identified ferro, antiferro, and re-entrant spin-glass phases in Ni–Fe–Cr alloys. • Resistivity ρ~−√T shows minima from 10–24 K due to electron–electron interaction. • Electron–phonon and electron–magnon contributions to ρ are isolated. • Magneto-transport measurements strengthened the magnetic phases identified. • Correlation in magnetic/electrical properties more meaningful if same samples used.

  2. Control of the radial electric field shear by modification of the magnetic field configuration in LHD

    International Nuclear Information System (INIS)

    Ida, K.; Yoshinuma, M.; Yokoyama, M.

    2005-01-01

    Control of the radial electric field, E γ , is considered to be important in helical plasmas, because the radial electric field and its shear are expected to reduce neoclassical and anomalous transport, respectively. In general, the radial electric field can be controlled by changing the collisionality, and positive or negative electric field have been obtained by decreasing or increasing the electron density, respectively. Although the sign of the radial electric field can be controlled by changing the collisionality, modification of the magnetic field is required to achieve further control of the radial electric field, especially producing a strong radial electric field shear. In the Large Helical Device (LHD) the radial electric field profiles are shown to be controlled by the modification of the magnetic field by 1) changing the radial profile of the helical ripples, ε h , 2) creating a magnetic island with an external perturbation field coil and 3) changing the local island divertor coil current. (author)

  3. Control of the radial electric field shear by modification of the magnetic field configuration in LHD

    International Nuclear Information System (INIS)

    Ida, K.; Yoshinuma, M.; Yokoyama, M.

    2005-01-01

    Control of the radial electric field, E r , is considered to be important in helical plasmas, because the radial electric field and its shear are expected to reduce neoclassical and anomalous transport, respectively. In general, the radial electric field can be controlled by changing the collisionality, and positive or negative electric fields have been obtained by decreasing or increasing the electron density, respectively. Although the sign of the radial electric field can be controlled by changing the collisionality, modification of the magnetic field is required to achieve further control of the radial electric field, especially to produce a strong radial electric field shear. In the Large Helical Device (LHD) the radial electric field profiles are shown to be controlled by the modification of the magnetic field by (1) changing the radial profile of the effective helical ripples, ε h (2) creating a magnetic island with an external perturbation field coil and (3) changing the local island divertor coil current

  4. Impact of electric and magnetic fields in a resistant medium on the ...

    African Journals Online (AJOL)

    In this paper, we compare the impact of electric and magnetic fields in a resistant medium on the velocity of a particle subject to varying path angles by using numerical integration of finite difference method. The results show that the magnetic field has much impact on the velocity than the electric field. Journal of the Nigerian ...

  5. Statistical analysis of the ratio of electric and magnetic fields in random fields generators

    NARCIS (Netherlands)

    Serra, R.; Nijenhuis, J.

    2013-01-01

    In this paper we present statistical models of the ratio of random electric and magnetic fields in mode-stirred reverberation chambers. This ratio is based on the electric and magnetic field statistics derived for ideal reverberation conditions. It provides a further performance indicator for

  6. Quantum phases for a charged particle and electric/magnetic dipole in an electromagnetic field

    Science.gov (United States)

    Kholmetskii, Alexander; Yarman, Tolga

    2017-11-01

    We point out that the known quantum phases for an electric/magnetic dipole moving in an electromagnetic field must be composed from more fundamental quantum phases emerging for moving elementary charges. Using this idea, we have found two new fundamental quantum phases, next to the known magnetic and electric Aharonov-Bohm phases, and discuss their general properties and physical meaning.

  7. Life Cycle Assessment of Neodymium-Iron-Boron Magnet-to-Magnet Recycling for Electric Vehicle Motors.

    Science.gov (United States)

    Jin, Hongyue; Afiuny, Peter; Dove, Stephen; Furlan, Gojmir; Zakotnik, Miha; Yih, Yuehwern; Sutherland, John W

    2018-03-20

    Neodymium-iron-boron (NdFeB) magnets offer the strongest magnetic field per unit volume, and thus, are widely used in clean energy applications such as electric vehicle motors. However, rare earth elements (REEs), which are the key materials for creating NdFeB magnets, have been subject to significant supply uncertainty in the past decade. NdFeB magnet-to-magnet recycling has recently emerged as a promising strategy to mitigate this supply risk. This paper assesses the environmental footprint of NdFeB magnet-to-magnet recycling by directly measuring the environmental inputs and outputs from relevant industries and compares the results with production from "virgin" materials, using life cycle assessments. It was found that magnet-to-magnet recycling lowers environmental impacts by 64-96%, depending on the specific impact categories under investigation. With magnet-to-magnet recycling, key processes that contribute 77-95% of the total impacts were identified to be (1) hydrogen mixing and milling (13-52%), (2) sintering and annealing (6-24%), and (3) electroplating (6-75%). The inputs from industrial sphere that play key roles in creating these impacts were electricity (24-93% of the total impact) and nickel (5-75%) for coating. Therefore, alternative energy sources such as wind and hydroelectric power are suggested to further reduce the overall environmental footprint of NdFeB magnet-to-magnet recycling.

  8. Counterstreaming electrons in small interplanetary magnetic flux ropes

    Science.gov (United States)

    Feng, H. Q.; Zhao, G. Q.; Wang, J. M.

    2015-12-01

    Small interplanetary magnetic flux ropes (SIMFRs) are commonly observed by spacecraft at 1 AU, and their origin still remains disputed. We investigated the counterstreaming suprathermal electron (CSE) signatures of 106 SIMFRs measured by Wind during 1995-2005. We found that 79 (75%) of the 106 flux ropes contain CSEs, and the percentages of counterstreaming vary from 8% to 98%, with a mean value of 51%. CSEs are often observed in magnetic clouds (MCs), and this indicates these MCs are still attached to the Sun at both ends. CSEs are also related to heliospheric current sheets (HCSs) and the Earth's bow shock. We divided the SIMFRs into two categories: The first category is far from HCSs, and the second category is in the vicinity of HCSs. The first category has 57 SIMFRs, and only 7 of 57 ropes have no CSEs. This ratio is similar to that of MCs. The second category has 49 SIMFRs; however, 20 of the 49 events have no CSEs. This ratio is larger than that of MCs. These two categories have different origins. One category originates from the solar corona, and most ropes are still connected to the Sun at both ends. The other category is formed near HCSs in the interplanetary space.

  9. Electric-field-induced magnetic domain writing in a Co wire

    Science.gov (United States)

    Tanaka, Yuki; Hirai, Takamasa; Koyama, Tomohiro; Chiba, Daichi

    2018-05-01

    We have demonstrated that the local magnetization in a Co microwire can be switched by an application of a gate voltage without using any external magnetic fields. The electric-field-induced reversible ferromagnetic phase transition was used to realize this. An internal stray field from a ferromagnetic gate electrode assisted the local domain reversal in the Co wire. This new concept of electrical domain switching may be useful for dramatically reducing the power consumption of writing information in a magnetic racetrack memory, in which a shift of a magnetic domain by electric current is utilized.

  10. The Feasibility of Small Hydro-Electric Generation in a Large Urban Area

    OpenAIRE

    Benson Y. Zhang; Adam Taylor

    2012-01-01

    The possibilities of generating electric power from relatively small hydro-electric sources in a large urban area is investigated. Two different aspects of hydro-electric sources have been studied: storm/waste water pipes in large multi-tenanted residential buildings and urban storm water discharge area (CSI area). The potential to generate from these sources has been investigated using a micro-turbine. The potential electric power which could be extracted from the sources was estimated using...

  11. Microscopic Description of Electric and Magnetic Toroidal Multipoles in Hybrid Orbitals

    Science.gov (United States)

    Hayami, Satoru; Kusunose, Hiroaki

    2018-03-01

    We derive the quantum-mechanical operator expressions of multipoles under the space-time inversion group. We elucidate that electric and magnetic toroidal multipoles, in addition to ordinary non-toroidal ones, are fundamental pieces to express arbitrary electronic degrees of freedom. We show that electric (magnetic) toroidal multipoles higher than the dipole (monopole) can become active in a hybridized-orbital system. We also demonstrate emergent cross-correlated couplings between the electric, magnetic, and elastic degrees of freedom, such as magneto-electric and magneto(electro)-elastic coupling, under toroidal multipole orders.

  12. Resonance scattering formalism for the hydrogen lines in the presence of magnetic and electric fields

    International Nuclear Information System (INIS)

    Casini, Roberto

    2005-01-01

    We derive a formalism for the computation of resonance-scattering polarization of hydrogen lines in the presence of simultaneous magnetic and electric fields, within a framework of the quantum theory of polarized line formation in the limit of complete frequency redistribution and of collisionless regime. Quantum interferences between fine-structure levels are included in this formalism. In the presence of a magnetic field, these interferences affect, together with the magnetic Hanle effect, the polarization of the atomic levels. In the presence of an electric field, interferences between distinct orbital configurations are also induced, further affecting the polarization of the hydrogen levels. In turn, the electric field is expected to affect the polarization of the atomic levels (electric Hanle effect), in a way analogous to the magnetic Hanle effect. We find that the simultaneous action of electric and magnetic fields give rise to complicated patterns of polarization and depolarization regimes, for varying geometries and field strengths

  13. Procedures for measuring the electrical properties of superconductors for accelerator magnets

    International Nuclear Information System (INIS)

    Sampson, W.B.

    1986-01-01

    There are three important electrical properties associated with the superconductor used to fabricate accelerator magnets. The most important is the critical current since this determines the performance potential of the magnet. The normal state resistivity and the volume magnetization are the other principal electrical parameters. In this report methods for measuring these parameters are presented and procedures for including self field effect and magnetoresistance are discussed

  14. Effect of mobilities and electric field on the stability of magnetized positive column

    International Nuclear Information System (INIS)

    Dogra, V.K.; Uberoi, M.S.

    1983-01-01

    The effect of ratio of the mobilities of electrons and ions and non-dimensional electric field, on the stability of magnetized positive column for all unstable modes is studied in a self-consistent formulation for the perturbations of plasma density and electric potential. The minimum non-dimensional electric field at which magnetized positive column becomes unstable for different ratios of the mobilities of electrons and ions is also investigated. (author)

  15. Magnetic and electrical properties of epitaxial GeMn

    Energy Technology Data Exchange (ETDEWEB)

    Ahlers, Stefan

    2009-01-15

    In this work, GeMn magnetic semiconductors will be investigated. The fabrication of GeMn thin films with Mn contents up to 11.7% was realised with molecular beam epitaxy. At a fabrication temperature of 60 C, the suppression of Mn{sub x}Ge{sub y} phases could reproducibly be obtained. Dislocation free epitaxy of diamond-lattice type GeMn thin films was observed. In all fabrication conditions where Mn{sub x}Ge{sub y} suppression was feasible, an inhomogeneous dispersion of Mn was observed in form of a self-assembly of nanometre sized, Mn rich regions in a Ge rich matrix. Each Mn rich region exhibits ferromagnetic coupling with high Curie temperatures exceeding, in part, room temperature. The local ferromagnetic ordering leads to the formation of large, spatially separated magnetic moments, which induce a superparamagnetic behaviour of the GeMn thin films. At low temperatures {<=} 20 K, remanent behaviour was found to emerge. X-ray absorption experiments revealed a similarity of the Mn incorporation in diamond-lattice type GeMn thin films and in the hexagonal lattice of the intermetallic Mn{sub 5}Ge{sub 3} phase, respectively. These tetrahedra represent building blocks of the Mn{sub 5}Ge{sub 3} unit cell. The incorporation of Mn{sub 5}Ge{sub 3} building blocks was found to be accompanied by local structural disorder. The electrical properties of GeMn thin films were addressed by transport measurements. It was shown that by using a n-type Ge substrate, a pn energy barrier between epilayers and substrate to suppress parallel substrate conduction paths can be introduced. With the pn barrier concept, first results on the magnetotransport behaviour of GeMn thin films were obtained. GeMn was found to be p-type, but of high resistivity. a series of GeMn thin films was fabricated, where intermetallic Mn{sub x}Ge{sub y} phase separation was supported in a controlled manner. Phase separation was found to result in the formation of partially coherent, nanometre sized Mn{sub 5

  16. optimal selection of hydraulic turbines for small hydro electric power

    African Journals Online (AJOL)

    eobe

    Keywords: optimal selection, SHP turbine, flow duration curve, energy efficiency, annual capacity factor. 1. INTRODUCTION ... depleted, with adverse environmental impacts downstream ..... Technologies, Financing Cogeneration and Small -.

  17. Radial electric field and transport near the rational surface and the magnetic island in LHD

    International Nuclear Information System (INIS)

    Ida, K.; Inagaki, S.; Tamura, N.

    2002-10-01

    The structure of the radial electric field and heat transport at the magnetic island in the Large Helical Device is investigated by measuring the radial profile of poloidal flow with charge exchange spectroscopy. The convective poloidal flow inside the island is observed when the n/m=1/1 external perturbation field becomes large enough to increase the magnetic island width above a critical value (15-20% of minor radius) in LHD. This convective poloidal flow results in a non-flat space potential inside the magnetic island. The sign of the curvature of the space potential depends on the radial electric field at the boundary of the magnetic island. The heat transport inside the magnetic island is studied with a cold pulse propagation technique. The experimental results show the existence of the radial electric field shear at the boundary of the magnetic island and a reduction of heat transport inside the magnetic island. (author)

  18. Heisenberg spin-1/2 XXZ chain in the presence of electric and magnetic fields

    Science.gov (United States)

    Thakur, Pradeep; Durganandini, P.

    2018-02-01

    We study the interplay of electric and magnetic order in the one-dimensional Heisenberg spin-1/2 XXZ chain with large Ising anisotropy in the presence of the Dzyaloshinskii-Moriya (DM) interaction and with longitudinal and transverse magnetic fields, interpreting the DM interaction as a coupling between the local electric polarization and an external electric field. We obtain the ground state phase diagram using the density matrix renormalization group method and compute various ground state quantities like the magnetization, staggered magnetization, electric polarization and spin correlation functions, etc. In the presence of both longitudinal and transverse magnetic fields, there are three different phases corresponding to a gapped Néel phase with antiferromagnetic (AF) order, gapped saturated phase, and a critical incommensurate gapless phase. The external electric field modifies the phase boundaries but does not lead to any new phases. Both external magnetic fields and electric fields can be used to tune between the phases. We also show that the transverse magnetic field induces a vector chiral order in the Néel phase (even in the absence of an electric field) which can be interpreted as an electric polarization in a direction parallel to the AF order.

  19. Relation between magnetic fields and electric currents in plasmas

    Directory of Open Access Journals (Sweden)

    V. M. Vasyliunas

    2005-10-01

    Full Text Available Maxwell's equations allow the magnetic field B to be calculated if the electric current density J is assumed to be completely known as a function of space and time. The charged particles that constitute the current, however, are subject to Newton's laws as well, and J can be changed by forces acting on charged particles. Particularly in plasmas, where the concentration of charged particles is high, the effect of the electromagnetic field calculated from a given J on J itself cannot be ignored. Whereas in ordinary laboratory physics one is accustomed to take J as primary and B as derived from J, it is often asserted that in plasmas B should be viewed as primary and J as derived from B simply as (c/4π∇×B. Here I investigate the relation between ∇×B and J in the same terms and by the same method as previously applied to the MHD relation between the electric field and the plasma bulk flow vmv2001: assume that one but not the other is present initially, and calculate what happens. The result is that, for configurations with spatial scales much larger than the electron inertial length λe, a given ∇×B produces the corresponding J, while a given J does not produce any ∇×B but disappears instead. The reason for this can be understood by noting that ∇×B≠4π/cJ implies a time-varying electric field (displacement current which acts to change both terms (in order to bring them toward equality; the changes in the two terms, however, proceed on different time scales, light travel time for B and electron plasma period for J, and clearly the term changing much more slowly is the one that survives. (By definition, the two time scales are equal at λe. On larger scales, the evolution of B (and hence also of ∇×B is governed by

  20. Comparison of nuclear electric resonance and nuclear magnetic resonance in integer and fractional quantum Hall states

    International Nuclear Information System (INIS)

    Tomimatsu, Toru; Shirai, Shota; Hashimoto, Katsushi; Sato, Ken; Hirayama, Yoshiro

    2015-01-01

    Electric-field-induced nuclear resonance (NER: nuclear electric resonance) involving quantum Hall states (QHSs) was studied at various filling factors by exploiting changes in nuclear spins polarized at quantum Hall breakdown. Distinct from the magnetic dipole interaction in nuclear magnetic resonance, the interaction of the electric-field gradient with the electric quadrupole moment plays the dominant role in the NER mechanism. The magnitude of the NER signal strongly depends on whether electronic states are localized or extended. This indicates that NER is sensitive to the screening capability of the electric field associated with QHSs

  1. Electric Dipole Antennas With Magnetic-Coated PEC Cores: Reaching the Chu Lower Bound on Q

    DEFF Research Database (Denmark)

    Kim, Oleksiy S.

    2012-01-01

    The radiation properties of spherical electric dipole antennas with electric current excitation and material-coated perfectly electrically conducting (PEC) cores are investigated analytically using vector spherical wave functions. Closed-form expressions for electric and magnetic stored energy...... as well as the radiation quality factor $Q$ are derived. Using these, it is shown that properly selected magnetic coating and radius of the PEC core vastly reduce the internal stored energy, and thus make the $Q$ of an electric dipole antenna approach the Chu lower bound....

  2. Electric-field control of magnetism via strain transfer across ferromagnetic/ferroelectric interfaces.

    Science.gov (United States)

    Taniyama, Tomoyasu

    2015-12-23

    By taking advantage of the coupling between magnetism and ferroelectricity, ferromagnetic (FM)/ferroelectric (FE) multiferroic interfaces play a pivotal role in manipulating magnetism by electric fields. Integrating the multiferroic heterostructures into spintronic devices significantly reduces energy dissipation from Joule heating because only an electric field is required to switch the magnetic element. New concepts of storage and processing of information thus can be envisioned when the electric-field control of magnetism is a viable alternative to the traditional current based means of controlling magnetism. This article reviews some salient aspects of the electric-field effects on magnetism, providing a short overview of the mechanisms of magneto-electric (ME) coupling at the FM/FE interfaces. A particular emphasis is placed on the ME effect via interfacial magneto-elastic coupling arising from strain transfer from the FE to FM layer. Recent results that demonstrate the electric-field control of magnetic anisotropy, magnetic order, magnetic domain wall motion, and etc are described. Obstacles that need to be overcome are also discussed for making this a reality for future device applications.

  3. Electric-field control of magnetism via strain transfer across ferromagnetic/ferroelectric interfaces

    International Nuclear Information System (INIS)

    Taniyama, Tomoyasu

    2015-01-01

    By taking advantage of the coupling between magnetism and ferroelectricity, ferromagnetic (FM)/ferroelectric (FE) multiferroic interfaces play a pivotal role in manipulating magnetism by electric fields. Integrating the multiferroic heterostructures into spintronic devices significantly reduces energy dissipation from Joule heating because only an electric field is required to switch the magnetic element. New concepts of storage and processing of information thus can be envisioned when the electric-field control of magnetism is a viable alternative to the traditional current based means of controlling magnetism. This article reviews some salient aspects of the electric-field effects on magnetism, providing a short overview of the mechanisms of magneto-electric (ME) coupling at the FM/FE interfaces. A particular emphasis is placed on the ME effect via interfacial magneto-elastic coupling arising from strain transfer from the FE to FM layer. Recent results that demonstrate the electric-field control of magnetic anisotropy, magnetic order, magnetic domain wall motion, and etc are described. Obstacles that need to be overcome are also discussed for making this a reality for future device applications. (topical review)

  4. On planar quantum dynamics of a magnetic dipole moment in the presence of electric and magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Edilberto O. [Universidade Federal do Maranhao, Departamento de Fisica, Sao Luis, MA (Brazil)

    2014-10-15

    The planar quantum dynamics of a neutral particle with a magnetic dipole moment in the presence of electric and magnetic fields is considered. The criteria to establish the planar dynamics reveal that the resulting nonrelativistic Hamiltonian has a simplified expression without making approximations, and some terms have crucial importance for the system dynamics. (orig.)

  5. Electrical characteristics of a small plasma focus device

    International Nuclear Information System (INIS)

    Choi, P.; Favre, M.; Silva, P.; Chuaqui, H.; Wyndham, E.

    1996-01-01

    Efficient plasma focus operation relies on uniform initial breakdown across the insulator surface. The basic plasma focus electric circuit is discussed in order to highlight circuit modifications that produce high voltage oscillation at the initial breakdown time. Superimposed on the main discharge voltage, such oscillating voltage has been found in real systems to enhance the initial gas breakdown by localizing the initial current path across the insulator surface. PSPICE circuit simulations are compared with electric signals from different operational plasma focus devices. (author). 3 figs., 7 refs

  6. Joint punching and frequency effects on practical magnetic characteristics of electrical steels for high-speed machines

    Science.gov (United States)

    Kedous-Lebouc, A.; Messal, O.; Youmssi, A.

    2017-03-01

    Mechanical punching of electrical steels causes a degradation of their magnetic characteristics which can extend several millimeters from the cut edge. So, in the field of industrial applications, particularly that of small electrical machines, the stator core made of rigid and thin teeth would be subject to more losses. Thus, this topic of the effect of punching has to be submitted to further deep characterization and development in order to give some insight into the different mechanisms. In this framework, this paper evaluates the combined effect of punching and frequency on the magnetization curve and iron losses in thin SiFe and CoFe soft magnetic sheets. These alloys are typically suitable for the manufacture of high-speed electrical machines used in on board applications (aircraft power generators, automotive, etc). Two SiFe alloys and a CoFe alloy have been investigated. First, different rectangular samples of variable width (15, 10, 5, 3 mm) have been industrially punched. Then, a dedicated magnetic characterization has been made, using basically a mini-Epstein frame. Measurements have been performed from 50 Hz to 1 kHz and from 0.3 T to near saturation. Both rolling and transverse directions have been considered. Finally, a first attempt to predict the degradation due to the punching is presented. A useful description of the magnetic permeability as a function of B and f is given and the degradation parameters are estimated based on the knowledge of the reference permeability.

  7. Joint punching and frequency effects on practical magnetic characteristics of electrical steels for high-speed machines

    Energy Technology Data Exchange (ETDEWEB)

    Kedous-Lebouc, A. [Univ. Grenoble Alpes, G2Elab, F-38000 Grenoble, France — CNRS, G2Elab, F-38000 Grenoble (France); Messal, O., E-mail: oualid.messal@g2elab.grenoble-inp.fr [Univ. Grenoble Alpes, G2Elab, F-38000 Grenoble, France — CNRS, G2Elab, F-38000 Grenoble (France); Youmssi, A. [Université de N’gaoundéré, BP. 455 N’Gaoundéré (Cameroon)

    2017-03-15

    Mechanical punching of electrical steels causes a degradation of their magnetic characteristics which can extend several millimeters from the cut edge. So, in the field of industrial applications, particularly that of small electrical machines, the stator core made of rigid and thin teeth would be subject to more losses. Thus, this topic of the effect of punching has to be submitted to further deep characterization and development in order to give some insight into the different mechanisms. In this framework, this paper evaluates the combined effect of punching and frequency on the magnetization curve and iron losses in thin SiFe and CoFe soft magnetic sheets. These alloys are typically suitable for the manufacture of high-speed electrical machines used in on board applications (aircraft power generators, automotive, etc). Two SiFe alloys and a CoFe alloy have been investigated. First, different rectangular samples of variable width (15, 10, 5, 3 mm) have been industrially punched. Then, a dedicated magnetic characterization has been made, using basically a mini-Epstein frame. Measurements have been performed from 50 Hz to 1 kHz and from 0.3 T to near saturation. Both rolling and transverse directions have been considered. Finally, a first attempt to predict the degradation due to the punching is presented. A useful description of the magnetic permeability as a function of B and f is given and the degradation parameters are estimated based on the knowledge of the reference permeability.

  8. Health effects of low frequency electric and magnetic fields

    International Nuclear Information System (INIS)

    1992-06-01

    The US Department of Labor and the President's Office of Science and Technology Policy (STP) requested that the Committee on interagency Radiation Research and Policy Coordination (CIRRPC) conduct an independent evaluation of the reported health effects from exposure to low-frequency electric and magnetic fields (ELF-EMF), especially reports of carcinogenesis and reproductive and neurophysiological effects focusing on frequencies which appeared to be of greatest public concern. Oak Ridge Associated Universities (ORAU) was tasked by the CIRRPC to oversee the review by a panel of independent, non-Federal, scientists. Following their review of over 1000 journal articles, the ORAU Panel concluded ''... that there is no convincing evidence ... to support the contention that exposure to ELF-EMF generated by sources such as household appliances, video display terminals (10 to 30 KHz), and local power lines (15 to 180 Hz) are demonstrable health hazards.'' Although the Panel noted that some biological effects produced by these fields may be of scientific interest and warrant consideration for future research, it concluded that ''... in the broad scope of research needs in basic science and health research, any health concerns over exposures to these fields should not receive a high priority.'' This executive summary outlines the panel's investigation

  9. Electrical supply for MFTF-B superconducting magnet system

    International Nuclear Information System (INIS)

    Shimer, D.W.; Owen, E.W.

    1985-01-01

    The MFTF-B magnet system consists of 42 superconducting magnets which must operate continuously for long periods of time. The magnet power supply system is designed to meet the operational requirements of accuracy, flexibility, and reliability. The superconducting magnets require a protection system to protect against critical magnet faults of quench, current lead overtemperature, and overcurrent. The protection system is complex because of the large number of magnets, the strong coupling between magnets, and the high reliability requirement. This paper describes the power circuits and the components used in the design

  10. A small scale remote cooling system for a superconducting cyclotron magnet

    Science.gov (United States)

    Haug, F.; Berkowitz Zamorra, D.; Michels, M.; Gomez Bosch, R.; Schmid, J.; Striebel, A.; Krueger, A.; Diez, M.; Jakob, M.; Keh, M.; Herberger, W.; Oesterle, D.

    2017-02-01

    Through a technology transfer program CERN is involved in the R&D of a compact superconducting cyclotron for future clinical radioisotope production, a project led by the Spanish research institute CIEMAT. For the remote cooling of the LTc superconducting magnet operating at 4.5 K, CERN has designed a small scale refrigeration system, the Cryogenic Supply System (CSS). This refrigeration system consists of a commercial two-stage 1.5 W @ 4.2 K GM cryocooler and a separate forced flow circuit. The forced flow circuit extracts the cooling power of the first and the second stage cold tips, respectively. Both units are installed in a common vacuum vessel and, at the final configuration, a low loss transfer line will provide the link to the magnet cryostat for the cooling of the thermal shield with helium at 40 K and the two superconducting coils with two-phase helium at 4.5 K. Currently the CSS is in the testing phase at CERN in stand-alone mode without the magnet and the transfer line. We have added a “validation unit” housed in the vacuum vessel of the CSS representing the thermo-hydraulic part of the cyclotron magnet. It is equipped with electrical heaters which allow the simulation of the thermal loads of the magnet cryostat. A cooling power of 1.4 W at 4.5 K and 25 W at the thermal shield temperature level has been measured. The data produced confirm the design principle of the CSS which could be validated.

  11. Electric-field effects on electronic tunneling transport in magnetic barrier structures

    International Nuclear Information System (INIS)

    Guo Yong; Wang Hao; Gu Binglin; Kawazoe, Yoshiyuki

    2000-01-01

    Electronic transport properties in magnetic barrier structures under the influence of an electric field have been investigated. The results indicate that the characteristics of transmission resonance are determined not only by the structure and the incident wave vector but also strongly by the electric field. It is shown that the transmission coefficient at resonance in the low-energy range is suppressed by applying the electric field for electron tunneling through the magnetic barrier structure, arranged with identical magnetic barriers and wells. It is also shown that the transmission resonance is first enhanced up to optimal resonance, and then suppressed with further increased electric field for electron tunneling through the magnetic barrier structure, arranged with unidentical building blocks. Strong suppression of the current density is also found in the magnetic barrier structure, arranged with two different building blocks

  12. Non-abelian gauge invariant classical Lagrangian formalism for point electric and magnetic charge

    International Nuclear Information System (INIS)

    Brandt, R.A.; Neri, F.

    1978-01-01

    The classical electrodynamics of electrically charged point particles has been generalized to include non-Abelian gauge groups and to include magnetically charged point particles. In this paper these two distinct generalizations are unified into a non-Abelian gauge theory of electric and magnetic charge. Just as the electrically charged particles constitute the generalized source of the gauge fields, the magnetically charged particles constitute the generalized source of the dual fields. The resultant equations of motion are invariant to the original 'electric' non-Abelian gauge group, but, because of the absence of a corresponding 'magnetic' gauge group, there is no 'duality' symmetry between electric and magnetic quantities. However, for a class of solutions to these equations, which includes all known point electric and magnetic monopole constructions, there is shown to exist an equivalent description based on a magnetic, rather than electric, gauge group. The gauge potentials in general are singular on strings extending from the particle position to infinity, but it is shown that the observables are without string singularities, and that the theory is Lorentz invariant, provided a charge quantization condition is satisfied. This condition, deduced from a stability analysis, is necessary for the consistency of the classical non-Abelian theory, in contrast to the Abelian case, where such a condition is necessary only for the consistency of the quantum theory. It is also shown that in the classical theory the strings cannot be removed by gauge transformations, as they sometimes can be in the quantum theory. (Auth.)

  13. Electric-field assisted switching of magnetization in perpendicularly magnetized (Ga,Mn)As films at high temperatures

    Science.gov (United States)

    Wang, Hailong; Ma, Jialin; Yu, Xueze; Yu, Zhifeng; Zhao, Jianhua

    2017-01-01

    The electric-field effects on the magnetism in perpendicularly magnetized (Ga,Mn)As films at high temperatures have been investigated. An electric-field as high as 0.6 V nm-1 is applied by utilizing a solid-state dielectric Al2O3 film as a gate insulator. The coercive field, saturation magnetization and magnetic anisotropy have been clearly changed by the gate electric-field, which are detected via the anomalous Hall effect. In terms of the Curie temperature, a variation of about 3 K is observed as determined by the temperature derivative of the sheet resistance. In addition, electrical switching of the magnetization assisted by a fixed external magnetic field at 120 K is demonstrated, employing the gate-controlled coercive field. The above experimental results have been attributed to the gate voltage modulation of the hole density in (Ga,Mn)As films, since the ferromagnetism in (Ga,Mn)As is carrier-mediated. The limited modulation magnitude of magnetism is found to result from the strong charge screening effect introduced by the high hole concentration up to 1.10  ×  1021 cm-3, while the variation of the hole density is only about 1.16  ×  1020 cm-3.

  14. High uniformity magnetic coil for search of neutron electric dipole moment

    Energy Technology Data Exchange (ETDEWEB)

    Perez Galvan, A., E-mail: apg@caltech.edu [W.K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA, 91125 (United States); Plaster, B. [Department of Physics and Astronomy, University of Kentucky, Lexington, KY, 40506 (United States); Boissevain, J.; Carr, R.; Filippone, B.W.; Mendenhall, M.P.; Schmid, R. [W.K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA, 91125 (United States); Alarcon, R.; Balascuta, S. [Department of Physics, Arizona State University, Tempe, AZ 85287 (United States)

    2011-12-21

    We present in this article a prototype magnetic coil that has been developed for a new search for the electric dipole moment of the neutron at the Spallation Neutron Source at Oak Ridge National Laboratory. The gradients of the magnetic field generated by the coil have been optimized to reduce known systematic effects and to yield long polarization lifetimes of the trapped particles sampling the highly uniform magnetic field. Measurements of the field uniformity of this prototype magnetic coil are also presented.

  15. Applications concepts of small regenerative cryocoolers in superconducitng magnet systems

    NARCIS (Netherlands)

    van der Laan, M.T.G.; van der Laan, M.T.G.; Tax, R.B.; ten Kate, Herman H.J.

    1992-01-01

    Superconducting magnets are in growing use outside laboratories for example MRI scanners in hospitals. Other applications under development are magnet systems for separation, levitated trains and ship propulsion. The application of cryocoolers can make these systems more practical. Interfacing these

  16. Study and review of permanent magnets for electric vehicle propulsion motors

    Science.gov (United States)

    Strnat, K. J.

    1983-01-01

    A study of permanent magnets (PM) was performed in support of the DOE/NASA electric and hybrid vehicle program. PM requirements for electric propulsion motors are analyzed, design principles and relevant properties of magnets are discussed. Available PM types are reviewed. For the needed high-grade magnets, design data, commercial varieties and sources are tabulated, based on a survey of vendors. Economic factors such as raw material availability, production capability and cost are analyzed, especially for cobalt and the rare earths. Extruded Mn-Al-C magnets from Japan were experimentally characterized. Dynamic magnetic data for the range -50 deg to +150 deg C and some mechanical properties are reported. The state of development of the important PM material families is reviewed. Feasible improvements or new developments of magnets for electric vehicle motors are identified.

  17. Reversible control of magnetic interactions by electric field in a single-phase material.

    Science.gov (United States)

    Ryan, P J; Kim, J-W; Birol, T; Thompson, P; Lee, J-H; Ke, X; Normile, P S; Karapetrova, E; Schiffer, P; Brown, S D; Fennie, C J; Schlom, D G

    2013-01-01

    Intrinsic magnetoelectric coupling describes the interaction between magnetic and electric polarization through an inherent microscopic mechanism in a single-phase material. This phenomenon has the potential to control the magnetic state of a material with an electric field, an enticing prospect for device engineering. Here, we demonstrate 'giant' magnetoelectric cross-field control in a tetravalent titanate film. In bulk form, EuTiO(3), is antiferromagnetic. However, both anti and ferromagnetic interactions coexist between different nearest europium neighbours. In thin epitaxial films, strain was used to alter the relative strength of the magnetic exchange constants. We not only show that moderate biaxial compression precipitates local magnetic competition, but also demonstrate that the application of an electric field at this strain condition switches the magnetic ground state. Using first-principles density functional theory, we resolve the underlying microscopic mechanism resulting in G-type magnetic order and illustrate how it is responsible for the 'giant' magnetoelectric effect.

  18. CALCULATION METHOD OF ELECTRIC POWER LINES MAGNETIC FIELD STRENGTH BASED ON CYLINDRICAL SPATIAL HARMONICS

    Directory of Open Access Journals (Sweden)

    A.V. Erisov

    2016-05-01

    Full Text Available Purpose. Simplification of accounting ratio to determine the magnetic field strength of electric power lines, and assessment of their environmental safety. Methodology. Description of the transmission lines of the magnetic field by using techniques of spatial harmonic analysis in the cylindrical coordinate system is carried out. Results. For engineering calculations of electric power lines magnetic field with sufficient accuracy describes their first spatial harmonic magnetic field. Originality. Substantial simplification of the definition of the impact of the construction of transmission line poles on the value of its magnetic field and the bands of land alienation sizes. Practical value. The environmentally friendly projection electric power lines on the level of the magnetic field.

  19. Reproducibility and variability of quantitative magnetic resonance imaging markers in cerebral small vessel disease

    NARCIS (Netherlands)

    Guio, F. De; Jouvent, E.; Biessels, G.J.; Black, S.E.; Brayne, C.; Chen, C.; Cordonnier, C.; Leeuw, F.E. de; Dichgans, M.; Doubal, F.; Duering, M.; Dufouil, C.; Duzel, E.; Fazekas, F.; Hachinski, V.; Ikram, M.A.; Linn, J.; Matthews, P.M.; Mazoyer, B.; Mok, V.; Norrving, B.; O'Brien, J.T.; Pantoni, L.; Ropele, S.; Sachdev, P.; Schmidt, R.; Seshadri, S.; Smith, E.E.; Sposato, L.A.; Stephan, B.; Swartz, R.H.; Tzourio, C.; Buchem, M. van; Lugt, A. van der; Oostenbrugge, R.; Vernooij, M.W.; Viswanathan, A.; Werring, D.; Wollenweber, F.; Wardlaw, J.M.; Chabriat, H.

    2016-01-01

    Brain imaging is essential for the diagnosis and characterization of cerebral small vessel disease. Several magnetic resonance imaging markers have therefore emerged, providing new information on the diagnosis, progression, and mechanisms of small vessel disease. Yet, the reproducibility of these

  20. Reproducibility and variability of quantitative magnetic resonance imaging markers in cerebral small vessel disease

    NARCIS (Netherlands)

    De Guio, F. (François); Jouvent, E. (Eric); G.J. Biessels (Geert Jan); S.E. Black (Sandra); C. Brayne (Carol); C. Chen (Christopher); C. Cordonnier (Charlotte); H.F. de Leeuw (Frank); C. Kubisch (Christian); Doubal, F. (Fergus); Duering, M. (Marco); C. Dufouil (Carole); Duzel, E. (Emrah); F. Fazekas (Franz); V. Hachinski (Vladimir); M.K. Ikram (Kamran); J. Linn (Jennifer); P.M. Matthews (P.); B. Mazoyer (Bernard); Mok, V. (Vincent); B. Norrving (Bo); O'Brien, J.T. (John T.); Pantoni, L. (Leonardo); S. Ropele (Stefan); P.S. Sachdev (Perminder); R. Schmidt (Reinhold); S. Seshadri (Sudha); E.E. Smith (Eric); L.A. Sposato (Luciano A); B.C.M. Stephan; Swartz, R.H. (Richard H.); C. Tzourio (Christophe); M.A. van Buchem (Mark); A. van der Lugt (Aad); R.J. van Oostenbrugge (Robert); M.W. Vernooij (Meike); Viswanathan, A. (Anand); D.J. Werring (David); Wollenweber, F. (Frank); J.M. Wardlaw (J.); Chabriat, H. (Hugues)

    2016-01-01

    textabstractBrain imaging is essential for the diagnosis and characterization of cerebral small vessel disease. Several magnetic resonance imaging markers have therefore emerged, providing new information on the diagnosis, progression, and mechanisms of small vessel disease. Yet, the reproducibility

  1. Magnetic resonance imaging for precise radiotherapy of small laboratory animals

    Energy Technology Data Exchange (ETDEWEB)

    Frenzel, Thorsten [Universitaetsklinikum Hamburg-Eppendorf, Hamburg (Germany). Bereich Strahlentherapie; Universitaetsklinikum Hamburg-Eppendorf, Hamburg (Germany). Inst. fuer Anatomie und Experimentelle Morphologie; Kaul, Michael Gerhard; Ernst, Thomas Michael; Salamon, Johannes [Universitaetsklinikum Hamburg-Eppendorf, Hamburg (Germany). Klinik und Poliklinik fuer Diagnostische und Interventionelle Radiologie; Jaeckel, Maria [Universitaetsklinikum Hamburg-Eppendorf, Hamburg (Germany). Klinik und Poliklinik fuer Strahlentherapie und Radioonkologie; Schumacher, Udo [Universitaetsklinikum Hamburg-Eppendorf, Hamburg (Germany). Inst. fuer Anatomie und Experimentelle Morphologie; Kruell, Andreas [Universitaetsklinikum Hamburg-Eppendorf, Hamburg (Germany). Bereich Strahlentherapie

    2017-05-01

    Radiotherapy of small laboratory animals (SLA) is often not as precisely applied as in humans. Here we describe the use of a dedicated SLA magnetic resonance imaging (MRI) scanner for precise tumor volumetry, radiotherapy treatment planning, and diagnostic imaging in order to make the experiments more accurate. Different human cancer cells were injected at the lower trunk of pfp/rag2 and SCID mice to allow for local tumor growth. Data from cross sectional MRI scans were transferred to a clinical treatment planning system (TPS) for humans. Manual palpation of the tumor size was compared with calculated tumor size of the TPS and with tumor weight at necropsy. As a feasibility study MRI based treatment plans were calculated for a clinical 6 MV linear accelerator using a micro multileaf collimator (μMLC). In addition, diagnostic MRI scans were used to investigate animals which did clinical poorly during the study. MRI is superior in precise tumor volume definition whereas manual palpation underestimates their size. Cross sectional MRI allow for treatment planning so that conformal irradiation of mice with a clinical linear accelerator using a μMLC is in principle feasible. Several internal pathologies were detected during the experiment using the dedicated scanner. MRI is a key technology for precise radiotherapy of SLA. The scanning protocols provided are suited for tumor volumetry, treatment planning, and diagnostic imaging.

  2. Mechanisms explaining Coulomb's electric force & Lorentz's magnetic force from a classical perspective

    Science.gov (United States)

    Correnti, Dan S.

    2018-06-01

    The underlying mechanisms of the fundamental electric and magnetic forces are not clear in current models; they are mainly mathematical constructs. This study examines the underlying physics from a classical viewpoint to explain Coulomb's electric force and Lorentz's magnetic force. This is accomplished by building upon already established physics. Although no new physics is introduced, extension of existing models is made by close examination. We all know that an electron carries a bound cylindrical B-field (CBF) as it translates. Here, we show how the electron CBF plays an intrinsic role in the generation of the electric and magnetic forces.

  3. Modification of electric and magnetic dipole emission in anisotropic plasmonic systems.

    Science.gov (United States)

    Noginova, N; Hussain, R; Noginov, M A; Vella, J; Urbas, A

    2013-10-07

    In order to investigate the effects of plasmonic environments on spontaneous emission of magnetic and electric dipoles, we have studied luminescence of Eu³⁺ ions in close vicinity to gold nanostrip arrays. Significant changes in the emission kinetics, emission polarization, and radiation patterns have been observed in the wavelength range corresponding to the plasmonic resonance. The effect of the plasmonic resonance on the magnetic dipole transition ⁵D₀-->⁷F₁ is found to be very different from its effect on the electric dipole transitions. This makes Eu³⁺₋ containing complexes promising for mapping local distributions of magnetic and electric fields in metamaterials and plasmonic systems.

  4. Experimental insight into the magnetic and electrical properties of amorphous Ge1-xMnx

    Science.gov (United States)

    Conta, Gianluca; Amato, Giampiero; Coïsson, Marco; Tiberto, Paola

    2017-12-01

    We present a study of the electrical and magnetic properties of the amorphous Ge1-xMnx.DMS, with 2% ≤ x ≤ 17%, by means of SQUID magnetometry and low temperature DC measurements. The thin films were grown by physical vapour deposition at 50°C in ultrahigh vacuum. The DC electrical characterizations show that variable range hopping is the main mechanism of charge transport below room temperature. Magnetic characterization reveals that a unique and smooth magnetic transition is present in our samples, which can be attributed to ferromagnetic percolation of bound magnetic polarons.

  5. Dirac particles in the field of magnetic monopoles and of strong electric charges

    International Nuclear Information System (INIS)

    Schafer, A.; Muller, B.; Greiner, W.

    1985-01-01

    The field of a magnetic pointlike monopole acts in a similar way on a charged Dirac particle as the field of a very strong electric point charge. To explore this parallel it is constructed a field solution for an extended magnetic-charge distribution. In contrast to what is found for extended electric charges, the Hamiltonian remains nonself-adjoint for an extended magnetic monopole. This suggests that there exist a fundamental difference between the two cases. In particular, the appearance of undefined states for point monopoles is not a consequence of the mere strength of the magnetic-monopole charge, which has a minimum value fixed by Dirac's quantization condition

  6. Realizability of metamaterials with prescribed electric permittivity and magnetic permeability tensors

    International Nuclear Information System (INIS)

    Milton, Graeme W

    2010-01-01

    We show that any pair of real symmetric tensors ε and μ can be realized as the effective electric permittivity and effective magnetic permeability of a metamaterial at a given fixed frequency. The construction starts with two extremely low-loss metamaterials, with arbitrarily small microstructure, whose existence is ensured by the work of Bouchitte and Bourel and Bouchitte and Schweizer: one having, at the given frequency, a permittivity tensor with exactly one negative eigenvalue, and a positive permeability tensor; and the other having a positive permittivity tensor, and a permeability tensor having exactly one negative eigenvalue. To achieve the desired effective properties, these materials are laminated together in a hierarchical multiple rank laminate structure, with widely separated length scales, and varying directions of lamination, but with the largest length scale still much shorter than the wavelengths and attenuation lengths in the macroscopic effective medium.

  7. Dynamic modeling of a thermo-piezo-electrically actuated nanosize beam subjected to a magnetic field

    Science.gov (United States)

    Ebrahimi, Farzad; Barati, Mohammad Reza

    2016-04-01

    In this article, free vibration behavior of magneto-electro-thermo-elastic functionally graded nanobeams is investigated based on a higher order shear deformation beam theory. Four types of thermal loading including uniform and linear temperature change as well as heat conduction and sinusoidal temperature rise through the thickness are assumed. Magneto-electro-thermo-elastic properties of FG nanobeam are supposed to change continuously throughout the thickness based on power-law model. Via nonlocal elasticity theory of Eringen, the small size effects are adopted. Based upon Hamilton's principle, the coupled nonlocal governing equations for higher order shear deformable METE-FG nanobeams are obtained and they are solved applying analytical solution. It is shown that the vibrational behavior of METE-FG nanobeams is significantly affected by various temperature rises, magnetic potential, external electric voltage, power-law index, nonlocal parameter and slenderness ratio.

  8. Bistability induced by crossed electric and magnetic fields in a nematic film

    Science.gov (United States)

    Barbero, G.; Miraldi, E.; Oldano, C.

    1988-09-01

    The static distortions in a homogeneously aligned nematic liquid-crystal film in crossed electric and magnetic fields are theoretically analyzed. Both fields are orthogonal to the undistorted molecular alignment and destabilizing. In the limit of small distortions, a first-order transition between two distorted configurations, with bistability and hysteresis, is obtained if the dielectric anisotropy parameter 1-ɛ∥/ɛ⊥ is lower than the elastic anisotropy parameter (k3-k2)2/(4k1k2), where k1, k2, and k3 are the Frank elastic constants. This condition is satisfied by many commonly used nematic materials. At higher distortions an inversion point is found, above which the transition becomes of the second order. At this point a phenomenon similar to the critical opalescence of fluids is expected.

  9. Electric field with bipolar structure during magnetic reconnection without a guide field

    Science.gov (United States)

    Guo, Jun

    2014-05-01

    We present a study on the polarized electric field during the collisionless magnetic reconnection of antiparallel fields using two dimensional particle-in-cell simulations. The simulations demonstrate clearly that electron holes and electric field with bipolar structure are produced during magnetic reconnection without a guide field. The electric field with bipolar structure can be found near the X-line and on the separatrix and the plasma sheet boundary layer, which is consistent with the observations. These structures will elongate electron's time staying in the diffusion region. In addition, the electric fields with tripolar structures are also found in our simulation.

  10. Electromagnetic processes in pulsars under strong electric and magnetic field conditions

    International Nuclear Information System (INIS)

    Ayasli, S.; Hacinliyan, A.; Oegelman, H.B.; Daugherty, I.K.

    1977-01-01

    It is believed that pulsars possess huge electric and magnetic fields. However, the electric field is commonly neglected in calculations of the rate of pair production, a process which is thought to be greatly important in the radiation mechanisms of pulsars. To see the effect of the electric field, the pair production is calculated for arbitrary electric and magnetic field configurations. The formulae thus obtained are then applied to pulsars. It is shown that the correction to the ''polar gap'' height calculated in the Ruderman and Sutherland model is negligible, although it might be important for the spectrum of emerging photons. (author)

  11. Electrical and magnetic fields of the power supply; Elektrische und magnetische Felder der Stromversorgung

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2017-01-15

    The availability of electrical energy in all areas of life is guaranteed by a widely ramified power grid. When electricity is transported, magnetic fields are created in addition to the electrical fields. In this brochure one will learn more about the causes and effects of electrical and magnetic fields as well as protection concepts and preventive measures. [German] Die Verfuegbarkeit von elektrischer Energie in allen Lebensbereichen wird von einem weit verzweigten Stromnetz gewaehrleistet. Wird Elektrizitaet transportiert, entstehen zusaetzlich zu den elektrischen auch magnetische Felder. In dieser Broschuere erfaehrt man mehr zu Ursachen und Wirkungen elektrischer und magnetischer Felder sowie Schutzkonzepten und Vorsorgemassnahmen.

  12. Impulse breakdown of small air gap in electric field Part II: Statistical ...

    African Journals Online (AJOL)

    The patterns of shot distribution and maximum coverage at impulse breakdown voltage for positive point electr-odes (needle and cone electrodes) in small air gaps in non-uniform electric fields were investigated. During the breakdown test, a sheet of paper was placed on the plate electrode (-ve), and each breakdown shot ...

  13. New Balancing Equipment for Mass Production of Small and Medium-Sized Electrical Machines

    DEFF Research Database (Denmark)

    Argeseanu, Alin; Ritchie, Ewen; Leban, Krisztina Monika

    2010-01-01

    The level of vibration and noise is an important feature. It is good practice to explain the significance of the indicators of the quality of electrical machines. The mass production of small and medium-sized electrical machines demands speed (short typical measurement time), reliability...

  14. Small Wind Electric Systems: A Virginia Consumer's Guide

    Energy Technology Data Exchange (ETDEWEB)

    2003-06-01

    The purpose of the Small Wind Electric Systems Consumer's: A Virginia Consumer's Guide is to provide consumers with enough information to help them determine if a small wind electric system will work for them based on their wind resource, the type and size of their sites, and their economics. The cover of this guide contains a Virginia wind resource map and information about state incentives and contacts for more information.

  15. Electric Field Controlled Magnetism in BiFeO3/Ferromagnet Films

    Science.gov (United States)

    Holcomb, M. B.; Chu, Y. H.; Martin, L. W.; Gajek, M.; Seidel, J.; Ramesh, R.; Scholl, A.; Fraile-Rodriguez, A.

    2008-03-01

    Electric field control of magnetism is a hot technological topic at the moment due to its potential to revolutionize today's devices. Magnetoelectric materials, those having both electric and magnetic order and the potential for coupling between the two, are a promising avenue to approach electric control. BiFeO3, both a ferroelectric and an antiferromagnet, is the only single phase room temperature magnetoelectric that is currently known. In addition to other possibilities, its multiferroic nature has potential in the very active field of exchange bias, where an antiferromagnetic thin film pins the magnetic direction of an adjoining ferromagnetic layer. Since this antiferromagnet is electrically tunable, this coupling could allow electric-field control of the ferromagnetic magnetization. Direction determination of antiferromagnetic domains in BFO has recently been shown using linear and circular dichroism studies. Recently, this technique has been extended to look at the magnetic domains of a ferromagnetic grown on top of BFO. The clear magnetic changes induced by application of electric fields reveal the possibility of electric control.

  16. How the Performance of a Superconducting Magnet is affected by the Connection between a small cooler and the Magnet

    International Nuclear Information System (INIS)

    Green, Michael A.

    2005-01-01

    As low temperature cryocoolers become more frequently used to cool superconducting magnets, it becomes increasingly apparent that the connection between the cooler and the magnet has an effect on the design and performance of the magnet. In general, the use of small coolers can be considered in two different temperature ranges; (1) from 3.8 to 4.8 K for magnet fabricated with LTS conductor and (2) from 18 to 35 K for magnets fabricated using HTS conductor. In general, both temperature ranges call for the use of a two-stage cooler. The best method for connecting a cooler to the magnet depends on a number of factors. The factors include: (1) whether the cooler must be used to cool down the magnet from room temperature, (2) whether the magnet must have one or more reservoirs of liquid cryogen to keep the magnet cold during a loss of cooling, and (3) constraints on the distance from the cooler cold heads and the magnet and its shield. Two methods for connecting low temperature coolers to superconducting magnets have been studied. The first method uses a cold strap to connect the cold heads directly to the loads. This method is commonly used for cryogen-free magnets. The second method uses a thermal siphon and liquid cryogens to make the connection between the load being cooled and the cold head. The two methods of transferring heat from the magnet to the cooler low temperature cold head are compared for the two temperature ranges given above

  17. Measurement of ac electrical characteristics of SSC dipole magnets at Brookhaven

    International Nuclear Information System (INIS)

    Smedley, K.

    1992-04-01

    The SSC collider is designed to have circumference of 87 km. The superconducting magnets along the collider ring are grouped into ten sectors. Each sector, a string of average length of 8.7 km,m is powered by one power source located near the center of the sector. Because of the alternating-current (ac) electrical characteristics of the magnets, the power supply ripple currents and transients form a time and space distribution in the magnet string which affects particle motions. Additionally, since the power supply load is a magnet string, the current regulation loop design is highly dependent upon the ac electrical characteristics of the magnets. A means is needed to accurately determine the ac electrical characteristics of the superconducting magnets. The ac characteristics of magnets will be used to predict the ripple distribution of the long string of superconducting magnets. Magnet ac characteristics can also provide necessary information for the regulation loop design. This paper presents a method for measuring the ac characteristics of superconducting magnets. Two collider dipole magnets, one superconducting and one at room temperature, were tested at Brookhaven National Lab

  18. SCR-1: Design and construction of a small modular stellarator for magnetic confinement of plasma

    International Nuclear Information System (INIS)

    Barillas, L; Vargas, V I; Alpizar, A; Asenjo, J; Carranza, J M; Cerdas, F; Gutiérrez, R; Monge, J I; Mora, J; Morera, J; Peraza, H; Rojas, C; Rozen, D; Saenz, F; Sánchez, G; Sandoval, M; Trimiño, H; Umaña, J; Villegas, L F; Queral, V

    2014-01-01

    This paper describes briefly the design and construction of a small modular stellarator for magnetic confinement of plasma, called Stellarator of Costa Rica 1, or SCR-1; developed by the Plasma Physics Group of the Instituto Tecnológico de Costa Rica, PlasmaTEC. The SCR-1 is based on the small Spanish stellarator UST 1 , created by the engineer Vicente Queral. The SCR-1 will employ stainless steel torus-shaped vacuum vessel with a major radius of 460.33 mm and a cross section radius of 110.25 mm. A typical SCR-1 plasma will have an average radius 42.2 mm and a volume of 8 liters (0.01 m 3 ), and an aspect ratio of 5.7. The magnetic resonant field will be 0.0878 T, and a period of 2 (m=2) with a rotational transform of 0.3. The magnetic field will be provided by 12 modular coils, with 8 turns each, with an electrical current of 8704 A per coil (1088 A per turn of each coil). This current will be fed by a bank of cell batteries. The plasma will be heated by ECRH with magnetrons of a total power of 5 kW, in the first harmonic at 2.45 GHz. The expected electron temperature and density are 15 eV and 10 17 m −3 respectively with an estimated confinement time of 7.30 x 10 −4 ms. The initial diagnostics on the SCR-1 will consist of a Langmuir probe, a heterodyne microwave interferometer, and a field mapping system. The first plasma of the SCR-1 is expected at the end of 2011.

  19. CALCULATION OF MAGNETIC CHARACTERISTICS OF TRACTION ELECTRIC ENGINE WITH THE USE OF IMPROVED UNIVERSAL MAGNETIC CHARACTERISTICS

    Directory of Open Access Journals (Sweden)

    A. Y. Drubetskyi

    2017-06-01

    Full Text Available Purpose. The article is aimed to develop a technique for calculating the magnetic characteristics of uncompensated traction electric motors (TEM at any degree of attenuation of excitation based on the approximating expression for improved universal magnetic characteristics (UMC. It is also necessary to conduct an analysis of expressions for improved UMC with the aim of finding an expression that most fully satisfies the requirements for developing a technique for determining the inductive parameters of TEM. Methodology. It is necessary to determine the saturation coefficient for each degree of attenuation of the excitation for building the characteristics with the improved UMC. This can only be done analytically. To simplify the analytical finding of the saturation coefficient, the method based on solving a system of two equations is proposed, one of which is UMC itself, and the second one is a straight line whose angular coefficient is proportional to the saturation coefficient. Resulting values of the saturation coefficient for the excitation degrees β < 1 are essentially the coefficients of the shape of the magnetic characteristic. To get rid of the need to determine the coefficients of approximation each time in the calculation of characteristics a form of improved UMC is proposed, in which the magnetomotive force (MMF of the excitation winding serves as the argument's role. Findings. Using the improved UMC it is possible to calculate the characteristics of uncompensated TEMs for any degree of attenuation of excitation. The accuracy of the calculation at β = 1 does not differ from that in the calculation for UMC, proposed by Prof. M. D. Nakhodkin. The same accuracy is preserved at excitation degrees that are different from unity. Originality. An analytical technique for calculating the magnetic (speed characteristics of uncompensated TEM for any degree of attenuation with the help of an improved UMC is proposed. The analytical technique

  20. Magnetization configurations and hysteresis loops of small permalloy ellipses

    International Nuclear Information System (INIS)

    Schneider, M; Liszkowski, J; Rahm, M; Wegscheider, W; Weiss, D; Hoffmann, H; Zweck, J

    2003-01-01

    We investigated systematically the easy axis magnetization reversal of 20 nm thick permalloy ellipses with a fixed major axis of 1.47 μm and minor axes of 0.22-1.47 μm. Lorentz transmission electron microscopy was used to image the micromagnetic configurations during magnetization reversal. Hysteresis loops of single ellipses were recorded by means of micro-Hall magnetometry and could be traced back to certain reversal mechanisms observed by Lorentz microscopy. In most cases, the magnetization reversal is initiated by the evolution of a magnetization buckling, followed by the formation of a single, a double, or a trapped vortex configuration. For ellipses with high aspect ratio (length-to-width ratio), the magnetization switches in the reversed magnetic field without creation of a stable vortex configuration. Our experiments show that the characteristic field values for vortex creation, single vortex annihilation, and switching strongly depend on the shape anisotropy of the elements

  1. Energy transfers in dynamos with small magnetic Prandtl numbers

    KAUST Repository

    Kumar, Rohit

    2015-06-25

    We perform numerical simulation of dynamo with magnetic Prandtl number Pm = 0.2 on 10243 grid, and compute the energy fluxes and the shell-to-shell energy transfers. These computations indicate that the magnetic energy growth takes place mainly due to the energy transfers from large-scale velocity field to large-scale magnetic field and that the magnetic energy flux is forward. The steady-state magnetic energy is much smaller than the kinetic energy, rather than equipartition; this is because the magnetic Reynolds number is near the dynamo transition regime. We also contrast our results with those for dynamo with Pm = 20 and decaying dynamo. © 2015 Taylor & Francis.

  2. Potential interference of small neodymium magnets with cardiac pacemakers and implantable cardioverter-defibrillators.

    Science.gov (United States)

    Wolber, Thomas; Ryf, Salome; Binggeli, Christian; Holzmeister, Johannes; Brunckhorst, Corinna; Luechinger, Roger; Duru, Firat

    2007-01-01

    Magnetic fields may interfere with the function of cardiac pacemakers and implantable cardioverter-defibrillators (ICDs). Neodymium-iron-boron (NdFeB) magnets, which are small in size but produce strong magnetic fields, have become widely available in recent years. Therefore, NdFeB magnets may be associated with an emerging risk of device interference. We conducted a clinical study to evaluate the potential of small NdFeB magnets to interfere with cardiac pacemakers and ICDs. The effect of four NdFeB magnets (two spherical magnets 8 and 10 mm in diameter, a necklace made of 45 spherical magnets, and a magnetic name tag) was tested in forty-one ambulatory patients with a pacemaker and 29 patients with an ICD. The maximum distance at which the magnetic switch of a device was influenced was observed. Magnetic interference was observed in all patients. The maximum distance resulting in device interference was 3 cm. No significant differences were found with respect to device manufacturer and device types. Small NdFeB magnets may cause interference with cardiac pacemakers and ICDs. Patients should be cautioned about the interference risk associated with NdFeB magnets during daily life.

  3. Biological effects of exposure to low frequency electric and magnetic fields

    International Nuclear Information System (INIS)

    Ahnstroem, G.

    1992-10-01

    The biological effects of exposure to low frequency electric and magnetic fields are reviewed with the objective of summarizing effects directly relevant to considerations of the health and safety of exposed people

  4. Electric and magnetic field testing in vicinity of 110/x kV substations

    Directory of Open Access Journals (Sweden)

    Grbić Maja

    2016-01-01

    Full Text Available The levels of non-ionizing radiation (electric and magnetic fields at power frequency, which occur near 110/x kV substations are analyzed in this paper. The results of electric field strength and magnetic flux density measurements in the vicinity of three typical substations of the aforementioned voltage level are shown. With the purpose of estimating the exposure of the population to these fields, the obtained results were compared to the reference maximum levels set for increased sensitivity areas, which amount to 2 kV/m for electric field and 40 μT for magnetic flux density. The objective of the conducted analysis is to reach general conclusions on the levels of electric and magnetic fields, which may occur in the vicinity of the substations mentioned above, and evaluate their compliance with the national regulations on the population protection from non-ionizing radiation.

  5. Vertical Gradient Freezing Using Submerged Heater Growth With Rotation and With Weak Magnetic and Electric Fields

    National Research Council Canada - National Science Library

    Bliss, D. F; Holmes, A. M; Wang, X; Ma, N; Iseler, G. W

    2005-01-01

    ...) method utilizing a submerged heater. Electromagnetic stirring can be induced in the gallium-antimonide melt just above the crystal growth interface by applying a weak radial electric current in the melt together with a weak axial magnetic field...

  6. Right to electricity. The small-scale user in a liberalized market for electricity

    International Nuclear Information System (INIS)

    Stout, H.; Bergamin, R.

    2001-01-01

    Consumer issues are currently high on the agenda of public policy makers and managers of electricity service providers. It is thus particularly timely that the present volume explores the legal challenges related to the transformation of the electricity industry. This collection of essays will hopefully contribute to a better understanding of the issues and subsequently to the drafting of appropriate legal and policy responses [nl

  7. Gastric transit and small intestinal transit time and motility assessed by a magnet tracking system.

    Science.gov (United States)

    Worsøe, Jonas; Fynne, Lotte; Gregersen, Tine; Schlageter, Vincent; Christensen, Lisbet A; Dahlerup, Jens F; Rijkhoff, Nico J M; Laurberg, Søren; Krogh, Klaus

    2011-12-29

    Tracking an ingested magnet by the Magnet Tracking System MTS-1 (Motilis, Lausanne, Switzerland) is an easy and minimally-invasive method to assess gastrointestinal transit. The aim was to test the validity of MTS-1 for assessment of gastric transit time and small intestinal transit time, and to illustrate transit patterns detected by the system. A small magnet was ingested and tracked by an external matrix of 16 magnetic field sensors (4 × 4) giving a position defined by 5 coordinates (position: x, y, z, and angle: θ, φ). Eight healthy subjects were each investigated three times: (1) with a small magnet mounted on a capsule endoscope (PillCam); (2) with the magnet alone and the small intestine in the fasting state; and (3) with the magnet alone and the small intestine in the postprandial state. Experiment (1) showed good agreement and no systematic differences between MTS-1 and capsule endoscopy when assessing gastric transit (median difference 1 min; range: 0-6 min) and small intestinal transit time (median difference 0.5 min; range: 0-52 min). Comparing experiments (1) and (2) there were no systematic differences in gastric transit or small intestinal transit when using the magnet-PillCam unit and the much smaller magnetic pill. In experiments (2) and (3), short bursts of very fast movements lasting less than 5% of the time accounted for more than half the distance covered during the first two hours in the small intestine, irrespective of whether the small intestine was in the fasting or postprandial state. The mean contraction frequency in the small intestine was significantly lower in the fasting state than in the postprandial state (9.90 min-1 vs. 10.53 min-1) (p = 0.03). MTS-1 is reliable for determination of gastric transit and small intestinal transit time. It is possible to distinguish between the mean contraction frequency of small intestine in the fasting state and in the postprandial state.

  8. Vector optical fields with polarization distributions similar to electric and magnetic field lines.

    Science.gov (United States)

    Pan, Yue; Li, Si-Min; Mao, Lei; Kong, Ling-Jun; Li, Yongnan; Tu, Chenghou; Wang, Pei; Wang, Hui-Tian

    2013-07-01

    We present, design and generate a new kind of vector optical fields with linear polarization distributions modeling to electric and magnetic field lines. The geometric configurations of "electric charges" and "magnetic charges" can engineer the spatial structure and symmetry of polarizations of vector optical field, providing additional degrees of freedom assisting in controlling the field symmetry at the focus and allowing engineering of the field distribution at the focus to the specific applications.

  9. Can Lucifer Yellow Indicate Correct Permeability of Biological Cell Membrane under An Electric and Magnetic Field?

    OpenAIRE

    Tahereh Pourmirjafari Firoozabadi; Zeinab Shankayi; Azam Izadi; Seyed Mohammad Pourmirjafari Firoozabadi

    2015-01-01

    The effect of external magnetic and electric fields, in the range of electroporation and magnetoporation, on Lucifer Yellow (LY) fluorescence in the absence of cells is studied. Electric-field-induced quenching and magnetic field-induced increase are observed for fluorescence intensity of LY. Regard to the fact that the variation of field-induced fluorescence, even in the absence of cells, can be observed, the application of LY, as a marker, is debatable in electroporation and magnetoporation...

  10. Eddy current analysis by BEM utilizing loop electric and surface magnetic currents as unknowns

    International Nuclear Information System (INIS)

    Ishibashi, Kazuhisa

    2002-01-01

    The surface integral equations whose unknowns are the surface electric and magnetic currents are widely used in eddy current analysis. However, when the skin depth is thick, computational error is increased especially in obtaining electromagnetic fields near the edge of the conductor. In order to obtain the electromagnetic field accurately, we propose an approach to solve surface integral equations utilizing loop electric and surface magnetic currents as unknowns. (Author)

  11. Analyzing intrinsic plasmonic chirality by tracking the interplay of electric and magnetic dipole modes.

    Science.gov (United States)

    Hu, Li; Huang, Yingzhou; Pan, Lujun; Fang, Yurui

    2017-09-11

    Plasmonic chirality represents significant potential for novel nanooptical devices due to its association with strong chiroptical responses. Previous reports on plasmonic chirality mechanism mainly focus on phase retardation and coupling. In this paper, we propose a model similar to the chiral molecules for explaining the intrinsic plasmonic chirality mechanism of varies 3D chiral structures quantitatively based on the interplay and mixing of electric and magnetic dipole modes (directly from electromagnetic field numerical simulations), which forms mixed electric and magnetic polarizability.

  12. Effect of metallic and hyperbolic metamaterial surfaces on electric and magnetic dipole emission transitions

    DEFF Research Database (Denmark)

    Ni, X.; Naik, G. V.; Kildishev, A. V.

    2011-01-01

    Spontaneous emission patterns of electric and magnetic dipoles on different metallic surfaces and a hyperbolic metamaterial (HMM) surface were simulated using the dyadic Green’s function technique. The theoretical approach was verified by experimental results obtained by measuring angular......-dependent emission spectra of europium ions on top of different films. The results show the modified behavior of electric and magnetic dipoles on metallic and HMM surfaces. The results of numerical calculations agree well with experimental data....

  13. Magnetic properties of ultra-small goethite nanoparticles

    International Nuclear Information System (INIS)

    Brok, E; Frandsen, C; Madsen, D E; Mørup, S; Jacobsen, H; Birk, J O; Lefmann, K; Bendix, J; Pedersen, K S; Boothroyd, C B; Berhe, A A; Simeoni, G G

    2014-01-01

    Goethite (α-FeOOH) is a common nanocrystalline antiferromagnetic mineral. However, it is typically difficult to study the properties of isolated single-crystalline goethite nanoparticles, because goethite has a strong tendency to form particles of aggregated nanograins often with low-angle grain boundaries. This nanocrystallinity leads to complex magnetic properties that are dominated by magnetic fluctuations in interacting grains. Here we present a study of the magnetic properties of 5.7 nm particles of goethite by use of magnetization measurements, inelastic neutron scattering and Mössbauer spectroscopy. The ‘ultra-small’ size of these particles (i.e. that the particles consist of one or only a few grains) allows for more direct elucidation of the particles' intrinsic magnetic properties. We find from ac and dc magnetization measurements a significant upturn of the magnetization at very low temperatures most likely due to freezing of spins in canted spin structures. From hysteresis curves we estimate the saturation magnetization from uncompensated magnetic moments to be σ s  = 0.044 A m 2  kg −1 at room temperature. Inelastic neutron scattering measurements show a strong signal from excitations of the uniform mode (q = 0 spin waves) at temperatures of 100–250 K and Mössbauer spectroscopy studies show that the magnetic fluctuations are dominated by ‘classical’ superparamagnetic relaxation at temperatures above ∼170 K. From the temperature dependence of the hyperfine fields and the excitation energy of the uniform mode we estimate a magnetic anisotropy constant of around 1.0 × 10 5  J m −3 . (paper)

  14. Impact of Deficient Electricity Supply on the Operations of Small Scale Businesses in North East Nigeria

    Directory of Open Access Journals (Sweden)

    Ahmed Ado

    2015-03-01

    Full Text Available Electricity supply in Nigeria is often erratic. Consumers of electricity (residential, commercial and industrial consumers suffer untold hardships as the State Owned Enterprise; the Power Holding Company of Nigeria (PHCN has been unable to supply reliable power. This is despite massive injections of funds by the Federal Government into the operations of the company over recent years. The failure has significantly impacted negatively on the operations of the business sector especially the small scale subsector that operates with little capital and are thus in most cases unable to afford a back-up facility to ensure un-interrupted power supply for their operations. The study examined the impact of deficient electric power supply on the operations of small scale businesses operating in north east of Nigeria. From the population of small scale businesses, a sample was selected through the use of stratified random sampling to ensure the effective representation of the population of small scale businesses in north east Nigeria. Results from data analysis indicates the severity of electricity supply outages and the costs imposed by power supply outages on the operation of this class of businesses in the region. The paper therefore recommends the need for policy attention towards revitalizing the electricity sector of Nigeria for enhanced supply of electricity to the national economy. When this is achieved, the small business sub-sector will be in a position to effectively lead in the drive towards industrializing the Nigerian economy.

  15. Photodetachment electron flux of H− in combined electric and magnetic fields with arbitrary orientation

    International Nuclear Information System (INIS)

    Wang, De-hua

    2013-01-01

    Highlights: •On the basis of the semiclassical theory, the photodetachment electron flux of H − in combined electric field and magnetic field with arbitrary orientation has been studied for the first time. •Our calculation results suggest that the electron flux distributions on the detector plane is not only related to the angle between the electric and magnetic fields, but also related to the electron energy. •Our studies may guide the future experimental researches in the photodetachment microscopy of some more complex negative ions in the presence of external fields. -- Abstract: On the basis of the semi-classical theory, we calculate the photodetachment electron flux of H − in combined electric field and magnetic field with arbitrary orientation. Our results suggest that the electron flux distributions on the detector plane is not only related to the angle between the electric and magnetic fields, but also related to the electron energy. With the increase of the angle between the electric and magnetic field, the oscillating region in the electron flux distributions becomes smaller. In addition, we find with the increase of the detached electron's energy, the oscillating structure in the flux distributions becomes much more complicated. Therefore, the oscillation in the detached electron flux distributions can be controlled by adjusting the angle between the electric and magnetic field and the detached electron's energy. We hope that our studies may guide the future experimental researches in the photodetachment microscopy of negative ion in the presence of external fields

  16. Energy transfers in dynamos with small magnetic Prandtl numbers

    KAUST Repository

    Kumar, Rohit; Verma, Mahendra K.; Samtaney, Ravi

    2015-01-01

    We perform numerical simulation of dynamo with magnetic Prandtl number Pm = 0.2 on 10243 grid, and compute the energy fluxes and the shell-to-shell energy transfers. These computations indicate that the magnetic energy growth takes place mainly due

  17. Electricity and telecommunications regulatory institutions in small and developing countries

    Energy Technology Data Exchange (ETDEWEB)

    Stern, J. [London Business School, London (United Kingdom)

    2000-09-01

    The spread of utility liberalisation and privatisation to middle and low income developing countries raises the problem of whether and how they can establish an effective regulatory capability of whether the supply of regulatory services is likely to be insufficient. The paper presents evidence on the size of electricity regulatory agencies in 24 mainly middle and lower income countries as well as the number of high-level, specialist regulatory staff and the potential resource pool from post-school education. The paper also discusses how far the problem can be alleviated and/or avoided by the use of regulation by contract, regulation by multi-national regulatory agency or contracting-out. The paper concludes that such solutions are unlikely to be generally effective but that informal exchanges of information and pooling of resources between national regulators on a market-driven basis, as seen in Southern Africa and the EU, is a promising option. The paper concludes by pointing to the need to ascertain the minimum required regulatory capability in developing countries as perceived by Governments and potential investors. (author)

  18. Small-scale hydro-electric scheme in Roches, Switzerland

    International Nuclear Information System (INIS)

    Hausmann, M.

    2006-01-01

    The small hydropower plant (SHPP) project 'PCH Roches' is planned to be built in Roches, a small village located in the Jura region of the canton of Bern. The goal of this undertaking is to reactivate a site with hydro potential of the river Birs on a section that was already well exploited by some ancient SHPP (since 1953 or probably even earlier). Several modifications were performed on this plant over the years; not all contributed positively on its production figures. Following a transfer of the water rights in 1987, claims became loud against the owner to perform maintenance on the river banks and to modify the weir such that a free passage for the fishes will be granted. Those issues contributed to inflate a conflict which ended in the repeal of the water rights and a total plant shut down in 2001. The new project plans to reuse the existing pen stock and to carry out some refurbishing activities to grant security and better performance. The weir and the intake structure are also redesigned such that the water storage can be somewhat raised for normal operation; a weir gate will however allow to better discharge the river in flood situations. A new turbine house will be erected at the current location where the tail water pen stock rejoins the river. Hence, the existing old turbine house will be obsolete and the upper and lower pen stock sections are to be linked with each other. Limited by the existing pen stock size, the new plant is expected to produce some 50 kW power and 362,000 kWh/year. This represents an increase in energy generation of around 200% compared with the ancient SHPP. Gross head is 5.38 m, net head 4.12 m with a turbine flow of at least 1.6 m 3 /s. The expected energy sales price applicable to this project reaches about 0.17 CHF/kWh as per the current tariffs set by the grid owner. This project calls for the building of a state-of-the-art SHPP. It will avoid the total dismantling of the existing works to take place and allow the small

  19. MAGNETIC VERSUS ELECTRICAL STIMULATION IN THE INTERPOLATION TWITCH TECHNIQUE OF ELBOW FLEXORS

    Directory of Open Access Journals (Sweden)

    Sofia I. Lampropoulou

    2012-12-01

    Full Text Available The study compared peripheral magnetic with electrical stimulation of the biceps brachii m. (BB in the single pulse Interpolation Twitch Technique (ITT. 14 healthy participants (31±7 years participated in a within-subjects repeated-measures design study. Single, constant-current electrical and magnetic stimuli were delivered over the motor point of BB with supramaximal intensity (20% above maximum at rest and at various levels of voluntary contraction. Force measurements from right elbow isometric flexion and muscle electromyograms (EMG from the BB, the triceps brachii m. (TB and the abductor pollicis brevis m. (APB were obtained. The twitch forces at rest and maximal contractions, the twitch force-voluntary force relationship, the M-waves and the voluntary activation (VA of BB between magnetic and electrical stimulation were compared. The mean amplitude of the twitches evoked at MVC was not significantly different between electrical (0.62 ± 0.49 N and magnetic (0.81 ± 0.49 N stimulation (p > 0.05, and the maximum VA of BB was comparable between electrical (95% and magnetic (93% stimulation (p > 0. 05. No differences (p >0.05 were revealed in the BB M-waves between electrical (13.47 ± 0.49 mV.ms and magnetic (12.61 ± 0.58 mV.ms stimulation. The TB M-waves were also similar (p > 0.05 but electrically evoked APB M-waves were significantly larger than those evoked by magnetic stimulation (p < 0.05. The twitch-voluntary force relationship over the range of MVCs was best described by non-linear functions for both electrical and magnetic stimulation. The electrically evoked resting twitches were consistently larger in amplitude than the magnetically evoked ones (mean difference 3.1 ± 3.34 N, p < 0.05. Reduction of the inter-electrodes distance reduced the twitch amplitude by 6.5 ± 6.2 N (p < 0.05. The fundamental similarities in voluntary activation assessment of BB with peripheral electrical and magnetic stimulation point towards a promising

  20. Axial-field permanent magnet motors for electric vehicles

    Science.gov (United States)

    Campbell, P.

    1981-01-01

    The modelling of an anisotropic alnico magnet for the purpose of field computation involves assigning a value for the material's permeability in the transverse direction. This is generally based upon the preferred direction properties, being all that are easily available. By analyzing the rotation of intrinsic magnetization due to the self demagnetizing field, it is shown that the common assumptions relating the transverse to the preferred direction are not accurate. Transverse magnetization characteristics are needed, and these are given for Alnico 5, 5-7, and 8 magnets, yielding appropriate permeability values.

  1. Health-related biological effects of electric, magnetic, and electro-magnetic fields with special reference to nonthermal effects

    International Nuclear Information System (INIS)

    Stevenson, A.F.G.

    1993-02-01

    This expert report is a supplement to the report by L. von Klitzing (The actions and effects of electric, magnetic, and electro-magnetic fields in man with special reference to athermal effects) and concerns in particular the biological effects on cationic homeostasis and cell regulation with special reference to calcium and the effects on the pineal gland. The report concludes with statements on teratogenicity, concerogenicity, mutagenicity and a bibliography of literature. (VHE) [de

  2. Water-dispersible small monodisperse electrically conducting antimony doped tin oxide nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Peters, K.; Zeller, P.; Štefanić, G.; Skoromets, Volodymyr; Němec, Hynek; Kužel, Petr; Fattakhova-Rohlfing, D.

    2015-01-01

    Roč. 27, č. 3 (2015), 1090-1099 ISSN 0897-4756 R&D Projects: GA ČR GA13-12386S Grant - others:AVČR(CZ) M100101218 Institutional support: RVO:68378271 Keywords : conducting nanoparticles * electrical conductivity * charge transport Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 9.407, year: 2015

  3. Effective electric and magnetic polarizabilities of pointlike spin-1/2 particles

    OpenAIRE

    Silenko, A. J.

    2014-01-01

    Effective electric and magnetic polarizabilities of pointlike spin-1/2 particles possesing an anomalous magnetic moment are calculated with the transformation of an initial Hamiltonian to the Foldy-Wouthuysen representation. Polarizabilities of spin-1/2 and spin-1 particles are compared.

  4. Observations on Student Difficulties with Mathematics in Upper-Division Electricity and Magnetism

    Science.gov (United States)

    Pepper, Rachel E.; Chasteen, Stephanie V.; Pollock, Steven J.; Perkins, Katherine K.

    2012-01-01

    We discuss common difficulties in upper-division electricity and magnetism (E&M) in the areas of Gauss's law, vector calculus, and electric potential using both quantitative and qualitative evidence. We also show that many of these topical difficulties may be tied to student difficulties with mathematics. At the junior level, some students…

  5. Two dimensional analytical considerations of large magnetic and electric fields in laser produced plasmas

    International Nuclear Information System (INIS)

    Eliezer, S.; Loeb, A.

    1985-08-01

    A simple model in two dimensions is developed and solved analytically taking into account the electric and magnetic fields in laser procuded plasmas. The electric potential in this model is described by a nonlinear differential equation. The stationary solution of this model is consistent for -0.1 less than or equal to psi 6 v/cm]/[B/MGauss] approx. 1

  6. Non-Contact Circuit for Real-Time Electric and Magnetic Field Measurements

    Science.gov (United States)

    2015-10-01

    response, noise spectral density, and dynamic range. 15. SUBJECT TERMS electric field, magnetic field, 1Wire, low-power microcontroller 16. SECURITY...4 Fig. 4 Altium DesignerTM schematic showing the pin connections of our MSP430 microcontroller ...electrical characteristics of the attached cable. 2. Methods and Procedures The circuit’s primary design consists of a microcontroller , 8-channel digital-to

  7. Magnetoelectric coupling study in multiferroic Pb(Fe0.5Nb0.5)O3 ceramics through small and large electric signal standard measurements

    International Nuclear Information System (INIS)

    Raymond, Oscar; Siqueiros, Jesus M.; Font, Reynaldo; Portelles, Jorge

    2011-01-01

    Multifunctional multiferroic materials such as the single phase compound Pb(Fe 0.5 Nb 0.5 )O 3 (PFN), where ferroelectric and antiferromagnetic order coexist, are very promising and have great interest from the academic and technological points of view. In this work, coupling of the ferroelectric and magnetic moments is reported. For this study, a combination of the small signal response using the impedance spectroscopy technique and the electromechanical resonance method with the large signal response through standard ferroelectric hysteresis measurement, has been used with and without an applied magnetic field. The measurements to determine the electrical properties of the ceramic were performed as functions of the bias and poling electric fields. A simultaneous analysis of the complex dielectric constant ε-tilde, impedance Z-tilde, electric modulus M-tilde, admittance Y-tilde, and the electromechanical parameters and coupling factors is presented. The results are correlated with a previous study of structural, morphological, small signal dielectric frequency-temperature response, and the ferroelectric hysteretic, magnetic and magnetodielectric behaviors. The observed shifts of the resonance and antiresonance frequency values can be associated with change of the ferroelectric domain size favored by the readjustment of the oxygen octahedron when the magnetic field is applied. From P-E hysteresis loops obtained without and with an external applied magnetic field, a dc magnetoelectric coupling effect with maximum value of 4 kV/cm T (400 mV/cm Oe) was obtained.

  8. Electrical and magnetic properties of MgGa_(_2_-_x_)Fe_xO_4 ferrite

    International Nuclear Information System (INIS)

    Ribeiro, Vander Alkmin dos Santos

    2005-01-01

    The ceramics of the type ferrites are materials that present important characteristics of electrical conduction and magnetic properties, as much as material magnetic hard, how much of soft magnetic materials. The cubic ferrites of the spinel structure are oxides with chemical formula MFe_2O_4, where M is a divalent metallic ion. Due to characteristic of the spinel, diverse magnetic configurations are a gotten, depending on the occupation tax of the magnetic ion (in general iron) in each sublattice. The diluted ferrites possess general formula given for: MD_2_-_xFe_xO4, where M and D are diamagnetic ions, being D the ion of substitution doping and x is the concentration of ions of iron (0,002 ≤ x ≤ 0,350). The sample was prepared using ceramics techniques in reaction of solid state and later they were submitted to a magnetic characterization, electric and X-ray diffraction. The results of the magnetic characterization were gotten by a magnetometer of vibrant sample (VSM) EG&G-Princeton Applied Research, model 4500; the characterization for X-ray was used one X-ray diffractometer, model URD 65; of the Seifert & with. Electrical measurements DC were carried through with the use of a unit high-voltage measuring source - Keithley, model 237, where the voltage applied in the samples varied of 0-40 V, the high temperatures. Two types of contacts were used: the arrangement type 'sandwich', being the inferior electrode the proper door-sample, and the superior electrode with ring geometry and a silver was pasted on both sides of the samples to ensure good electrical contact. The magnetic measurements confirm its ferrite characteristics and in the electrical measurements, the electrical conductivity indicated behavior of a semiconductor the high temperatures and the process of electrical conduction thermally presented to be activated. (author)

  9. Electric-field responsive contrast agent based on liquid crystals and magnetic nanoparticles

    Science.gov (United States)

    Mair, Lamar O.; Martinez-Miranda, Luz J.; Kurihara, Lynn K.; Nacev, Aleksandar; Hilaman, Ryan; Chowdhury, Sagar; Jafari, Sahar; Ijanaten, Said; da Silva, Claudian; Baker-McKee, James; Stepanov, Pavel Y.; Weinberg, Irving N.

    2018-05-01

    The properties of liquid crystal-magnetic nanoparticle composites have potential for sensing in the body. We study the response of a liquid crystal-magnetic nanoparticle (LC-MNP) composite to applied potentials of hundreds of volts per meter. Measuring samples using X-ray diffraction (XRD) and imaging composites using magnetic resonance imaging (MRI), we demonstrate that electric potentials applied across centimeter scale LC-MNP composite samples can be detected using XRD and MRI techniques.

  10. On an effect of interplanetary magnetic field on a distribution electric fields in the polar ionosphere

    International Nuclear Information System (INIS)

    Uvarov, V.M.; Barashkov, P.D.

    1985-01-01

    The problem on the effect of the interplanetary magnetic field (IMF) on the distribution of electric fields in polar ionosphere is discussed. The problem on excitation of electric fields is reduced to the solution of the system of continuity equations for the current in three regions-northern polar cap, southern cap and the region outside the caps. It is shown that one succeeds in reproducing the observed types of distributions of electric fields

  11. Electrical control of 2D magnetism in bilayer CrI 3.

    Science.gov (United States)

    Huang, Bevin; Clark, Genevieve; Klein, Dahlia R; MacNeill, David; Navarro-Moratalla, Efrén; Seyler, Kyle L; Wilson, Nathan; McGuire, Michael A; Cobden, David H; Xiao, Di; Yao, Wang; Jarillo-Herrero, Pablo; Xu, Xiaodong

    2018-04-23

    Controlling magnetism via electric fields addresses fundamental questions of magnetic phenomena and phase transitions 1-3 , and enables the development of electrically coupled spintronic devices, such as voltage-controlled magnetic memories with low operation energy 4-6 . Previous studies on dilute magnetic semiconductors such as (Ga,Mn)As and (In,Mn)Sb have demonstrated large modulations of the Curie temperatures and coercive fields by altering the magnetic anisotropy and exchange interaction 2,4,7-9 . Owing to their unique magnetic properties 10-14 , the recently reported two-dimensional magnets provide a new system for studying these features 15-19 . For instance, a bilayer of chromium triiodide (CrI 3 ) behaves as a layered antiferromagnet with a magnetic field-driven metamagnetic transition 15,16 . Here, we demonstrate electrostatic gate control of magnetism in CrI 3 bilayers, probed by magneto-optical Kerr effect (MOKE) microscopy. At fixed magnetic fields near the metamagnetic transition, we realize voltage-controlled switching between antiferromagnetic and ferromagnetic states. At zero magnetic field, we demonstrate a time-reversal pair of layered antiferromagnetic states that exhibit spin-layer locking, leading to a linear dependence of their MOKE signals on gate voltage with opposite slopes. Our results allow for the exploration of new magnetoelectric phenomena and van der Waals spintronics based on 2D materials.

  12. Energy transfers and magnetic energy growth in small-scale dynamo

    KAUST Repository

    Kumar, Rohit Raj

    2013-12-01

    In this letter we investigate the dynamics of magnetic energy growth in small-scale dynamo by studying energy transfers, mainly energy fluxes and shell-to-shell energy transfers. We perform dynamo simulations for the magnetic Prandtl number Pm = 20 on 10243 grid using the pseudospectral method. We demonstrate that the magnetic energy growth is caused by nonlocal energy transfers from the large-scale or forcing-scale velocity field to small-scale magnetic field. The peak of these energy transfers moves towards lower wave numbers as dynamo evolves, which is the reason why the integral scale of the magnetic field increases with time. The energy transfers U2U (velocity to velocity) and B2B (magnetic to magnetic) are forward and local. Copyright © EPLA, 2013.

  13. Characterization of Plasmadynamics within a Small Magnetic Nozzle

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal presents an experimental and theoretical research project intended to develop a more refined model of the underlying physics of magnetic nozzles. The...

  14. Spin-driven ferroelectricity and magneto-electric effects in frustrated magnetic systems

    International Nuclear Information System (INIS)

    Arima, Taka-hisa

    2011-01-01

    The interplay between magnetism and electricity in matter has become a central issue of condensed-matter physics. This review focuses on the ferroelectricity induced by magnetic order mostly in frustrated magnets, which is nowadays referred to as magneto-electric (ME) multiferroic, or often only as multiferroic. Some distinct types of microscopic origins relevant to the spin-driven ferroelectricity are discussed in detail. Then one sees that the frustration-based spin-driven ferroelectrics can exhibit nonlinear and giant ME responses of phase-transition type and of domain-control type, in contrast to the conventional magnetoelectrics hosting linear ME effects. (author)

  15. New classical inversion formulas for centrosymmetric electric and magnetic fields; focusing potentials

    International Nuclear Information System (INIS)

    Bogdanov, I.V.; Demkov, Y.N.

    1982-01-01

    New inversion formulas are obtained for the classical scattering of a charged particle by a spherical or axisymmetric electric or magnetic field at a fixed impact parameter or angular momentum. For different cases, focusing fields are obtained similar to those previously considered for scattering by an electric field at a given energy, viz., of the backscattering (cat's eye), Maxwell fish eye, or Luneberg lens type. A magnetoelectric analogy is formulated, namely the existence of equivalent axisymmetric electric and magnetic fields that scatter charged particles in identical fashion

  16. Studies on mobility in electric and magnetic fields of tritium ions occluded in titanium and zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Pietrzak, R [Wyzsza Szkola Pedagogiczna, Opole (Poland); Rozenfeld, B [Wroclaw Univ. (Poland)

    1976-01-01

    Migration of tritium ions in zirconium and titanium in electric field has been investigated. The effect of simultaneous action of crossed electric and magnetic fields on ions migration has also been studied. The averaged values taken from the large number of measurements allow us to suggest the relation between the rate of electromobility and electric field intensity oriented in the direction of migration. In case of migration caused by simultaneously applied both field, the mobility varied monotonously with the increase of magnetic induction; a linear dependence, however, was observed between the mobility of tritium and the current density in a sample.

  17. Development and application of measurement techniques for evaluating localised magnetic properties in electrical steel

    Science.gov (United States)

    Lewis, N. J.; Anderson, P. I.; Gao, Y.; Robinson, F.

    2018-04-01

    This paper reports the development of a measurement probe which couples local flux density measurements obtained using the needle probe method with the local magnetising field attained via a Hall effect sensor. This determines the variation in magnetic properties including power loss and permeability at increasing distances from the punched edge of 2.4% and 3.2% Si non-oriented electrical steel sample. Improvements in the characterisation of the magnetic properties of electrical steels would aid in optimising the efficiency in the design of electric machines.

  18. Magnetic energy storage devices for small scale applications

    International Nuclear Information System (INIS)

    Kumar, B.

    1992-01-01

    This paper covers basic principles of magnetic energy storage, structure requirements and limitations, configurations of inductors, attributes of high-T c superconducting materials including thermal instabilities, a relative comparison with the state-of-the-art high energy density power sources, and refrigeration requirements. Based on these fundamental considerations, the design parameters of a micro superconducting magnetic energy unit for Air Force applications is presented and discussed

  19. Electronic and magnetic properties of small rhodium clusters

    Energy Technology Data Exchange (ETDEWEB)

    Soon, Yee Yeen; Yoon, Tiem Leong [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Lim, Thong Leng [Faculty of Engineering and Technology, Multimedia University, Melaka Campus, 75450 Melaka (Malaysia)

    2015-04-24

    We report a theoretical study of the electronic and magnetic properties of rhodium-atomic clusters. The lowest energy structures at the semi-empirical level of rhodium clusters are first obtained from a novel global-minimum search algorithm, known as PTMBHGA, where Gupta potential is used to describe the atomic interaction among the rhodium atoms. The structures are then re-optimized at the density functional theory (DFT) level with exchange-correlation energy approximated by Perdew-Burke-Ernzerhof generalized gradient approximation. For the purpose of calculating the magnetic moment of a given cluster, we calculate the optimized structure as a function of the spin multiplicity within the DFT framework. The resultant magnetic moments with the lowest energies so obtained allow us to work out the magnetic moment as a function of cluster size. Rhodium atomic clusters are found to display a unique variation in the magnetic moment as the cluster size varies. However, Rh{sub 4} and Rh{sub 6} are found to be nonmagnetic. Electronic structures of the magnetic ground-state structures are also investigated within the DFT framework. The results are compared against those based on different theoretical approaches available in the literature.

  20. Intraoral conversion of occlusal force to electricity and magnetism by biting of piezoelectric elements.

    Science.gov (United States)

    Kameda, Takashi; Ohkuma, Kazuo; Sano, Natsuki; Ogura, Hideo; Terada, Kazuto

    2012-01-01

    Very weak electrical, magnetic and ultrasound signal stimulations are known to promote the formation, metabolism, restoration and stability of bone and surrounding tissues after treatment and operations. We have therefore investigated the possibility of intraoral generation of electricity and magnetism by occlusal force in an in vitro study. Biting bimorph piezoelectric elements with lead zirconate titanate (PZT) using dental models generated appropriate magnetism for bone formation, i. e. 0.5-0.6 gauss, and lower electric currents and higher voltages, i. e. 2.0-6.0 μA at 10-22 V (appropriate levels are 30 μA and 1.25 V), as observed by a universal testing machine. The electric currents and voltages could be changed using amplifier circuits. These results show that intraoral generation of electricity and magnetism is possible and could provide post-operative stabilization and activation of treated areas of bone and the surrounding tissues directly and/or indirectly by electrical, magnetic and ultrasound stimulation, which could accelerate healing.

  1. Intense heavy-ion beam transport with electric and magnetic quadrupoles

    International Nuclear Information System (INIS)

    Fessenden, T.J.; Hopkins, H.S.

    1995-08-01

    As part of the small induction recirculator development at LLNL, the authors are testing an injector and transport line that delivers 4 micros beams of potassium with repetition rates up to 10 Hz at a nominal current of 2 mA. The normalized K-V equivalent emittance of the beams is near 0.02 π mm-mrad and is mostly determined by the temperature of the source (0.1 eV). K + ions generated at 80 keV in a Pierce diode are matched to an alternating gradient transport line by seven electric quadrupoles. Two additional quads have been modified to serve as two-axis steerers. The matching section is followed by a transport section comprised of seven permanent magnet quadrupoles. Matching to this section is achieved by adjusting the voltages on the electric quadrupoles to voltages calculated by an envelope matching code. Measurements of beam envelope parameters are made at the matching section entrance and exit as well as at the end of the permanent magnet transport section. Beam current waveforms along the experiment are compared with results from a one-dimension longitudinal dynamics code. Initial experiments show particle loss occurring at the beam head as a result of overtaking. The apparatus is also being used for the development of non or minimally intercepting diagnostics for future recirculator experiments. These include capacitive monitors for determining beam line-charge density and position in the recirculator; flying wire scanners for beam position; and gated TV scanners for measuring beam profiles and emittance

  2. Electrical control of memristance and magnetoresistance in oxide magnetic tunnel junctions

    KAUST Repository

    Zhang, Kun

    2015-01-01

    Electric-field control of magnetic and transport properties of magnetic tunnel junctions has promising applications in spintronics. Here, we experimentally demonstrate a reversible electrical manipulation of memristance, magnetoresistance, and exchange bias in Co/CoO–ZnO/Co magnetic tunnel junctions, which enables the realization of four nonvolatile resistance states. Moreover, greatly enhanced tunneling magnetoresistance of 68% was observed due to the enhanced spin polarization of the bottom Co/CoO interface. The ab initio calculations further indicate that the spin polarization of the Co/CoO interface is as high as 73% near the Fermi level and plenty of oxygen vacancies can induce metal–insulator transition of the CoO1−v layer. Thus, the electrical manipulation mechanism on the memristance, magnetoresistance and exchange bias can be attributed to the electric-field-driven migration of oxygen ions/vacancies between very thin CoO and ZnO layers.

  3. Manipulation of positron orbits in a dipole magnetic field with fluctuating electric fields

    Science.gov (United States)

    Saitoh, H.; Horn-Stanja, J.; Nißl, S.; Stenson, E. V.; Hergenhahn, U.; Pedersen, T. Sunn; Singer, M.; Dickmann, M.; Hugenschmidt, C.; Stoneking, M. R.; Danielson, J. R.; Surko, C. M.

    2018-01-01

    We report the manipulation of positron orbits in a toroidal dipole magnetic field configuration realized with electric fields generated by segmented electrodes. When the toroidal circulation motion of positrons in the dipole field is coupled with time-varying electric fields generated by azimuthally segmented outer electrodes, positrons undergo oscillations of their radial positions. This enables quick manipulation of the spatial profiles of positrons in a dipole field trap by choosing appropriate frequency, amplitude, phase, and gating time of the electric fields. According to numerical orbit analysis, we applied these electric fields to positrons injected from the NEPOMUC slow positron facility into a prototype dipole field trap experiment with a permanent magnet. Measurements with annihilation γ-rays clearly demonstrated the efficient compression effects of positrons into the strong magnetic field region of the dipole field configuration. This positron manipulation technique can be used as one of essential tools for future experiments on the formation of electron-positron plasmas.

  4. Pure Electric and Pure Magnetic Resonances in Near-Infrared Metal Double-Triangle Metamaterial Arrays

    International Nuclear Information System (INIS)

    Cao Zhi-Shen; Pan Jian; Chen Zhuo; Zhan Peng; Min Nai-Ben; Wang Zhen-Lin

    2011-01-01

    We experimentally and numerically investigate the optical properties of metamaterial arrays composed of double partially-overlapped metallic nanotriangles fabricated by an angle-resolved nanosphere lithography. We demonstrate that each double-triangle can be viewed as an artificial magnetic element analogous to the conventional metal split-ring-resonator. It is shown that under normal-incidence conditions, individual double-triangle can exhibit a strong local magnetic resonance, but the collective response of the metamaterial arrays is purely electric because magnetic resonances of the two double-triangles in a unit cell having opposite openings are out of phase. For oblique incidences the metamaterial arrays are shown to support a pure magnetic response at the same frequency band. Therefore, switchable electric and magnetic resonances are achieved in double-triangle arrays. Moreover, both the electric and magnetic resonances are shown to allow for a tunability over a large spectral range down to near-infrared. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  5. Phenomenon of the time-reversal violating magnetic field generation by a static electric field in a medium and vacuum

    OpenAIRE

    Baryshevsky, Vladimir G.

    1999-01-01

    It is shown that the T- and P-odd weak interactions yield to the existence of both electric field and magnetic (directed along the electric field) field around an electric charge. Similarly the assotiated magnetic field is directed along the vector of strength of stationary gravitational field.

  6. An electric motor with magnetic bearings: A concept

    Science.gov (United States)

    Studer, P. A.

    1973-01-01

    Because same magnetic flux is used to control rotor as to drive it, size, weight, and power required are minimized. Constant total current keeps motor torque invarient, and absence of mechanical bearings eliminates wear and reduces frictional power loss.

  7. Modulational instability of electric helicons in a magnetized collisional plasma

    International Nuclear Information System (INIS)

    El-Ashry, M.Y.; Papuashvili, N.A.

    1987-06-01

    The interaction of a rf electromagnetic wave with a magnetized collisional plasma in the ultra-relativistic case has been investigated to show the effect of the collisions on the modulational instability growth rate. (author). 5 refs

  8. Effect of substrate temperature on electrical and magnetic properties ...

    Indian Academy of Sciences (India)

    . Figure 1. The temperature dependence of resistivity for LPMO films grown at different substrate temperatures (solid and open circles are the data in zero and 1 T magnetic field). The inset shows the variation of magnetoresistance with ...

  9. Electronic, electrical and magnetic ceramics synthesis and characterization

    International Nuclear Information System (INIS)

    Calix, V.S.; Saligan, P.P.; Naval, P.C.

    1989-01-01

    This paper describes the research and development activities of the Philippine Nuclear Research Institute (PNRI) on the synthesis and characterization of soft and hard ferrites and some beta alumina type superionic conductor materials. XRD, XRF and Moessbauer effect spectrometry are used to determine the structure phases, compositions and some magnetic properties of the materials. Effects of composition and preparation methods on the bulk electronic and magnetic properties are also discussed. (Auth.). 6 figs.; 3 tabs

  10. Small Signal Stability Improvement of Power Systems Using Optimal Load Responses in Competitive Electricity Markets

    DEFF Research Database (Denmark)

    Hu, Weihao; Su, Chi; Chen, Zhe

    2011-01-01

    Since the hourly spot market price is available one day ahead in Denmark, the price could be transferred to the consumers and they may shift some of their loads from high price periods to the low price periods in order to save their energy costs. The optimal load response to an electricity price...... price is proposed. A 17-bus power system with high wind power penetrations, which resembles the Eastern Danish power system, is chosen as the study case. Simulation results show that the optimal load response to electricity prices is an effective measure to improve the small signal stability of power...... for demand side management generates different load profiles and may provide an opportunity to improve the small signal stability of power systems with high wind power penetrations. In this paper, the idea of power system small signal stability improvement by using optimal load response to the electricity...

  11. A cable-free impedance and gain measurement technique for electrically small antennas

    DEFF Research Database (Denmark)

    Pivnenko, Sergey; Zhang, Jiaying; Breinbjerg, Olav

    2010-01-01

    are represented in terms of spherical wave expansions (SWEs), and the propagation is accounted for by a transmission formula. In this paper the measurement results by the proposed technique will be presented for several AUTs, including a standard gain horn antenna, a monopole antenna, and an electrically small......Impedance and gain measurements for electrically small antennas represent a great challenge due to influences of the feeding cable. The leaking current along the cable and scattering effects are two main issues caused by the feed line. In this paper, a novel cable-free antenna impedance and gain...... measurement technique for electrically small antennas is proposed. The antenna properties are extracted by measuring the signal scattered by the antenna under test (AUT), when it is loaded with three known loads. The technique is based on a rigorous electromagnetic model where the probe and AUT...

  12. Method for providing slip energy control in permanent magnet electrical machines

    Science.gov (United States)

    Hsu, John S.

    2006-11-14

    An electric machine (40) has a stator (43), a permanent magnet rotor (38) with permanent magnets (39) and a magnetic coupling uncluttered rotor (46) for inducing a slip energy current in secondary coils (47). A dc flux can be produced in the uncluttered rotor when the secondary coils are fed with dc currents. The magnetic coupling uncluttered rotor (46) has magnetic brushes (A, B, C, D) which couple flux in through the rotor (46) to the secondary coils (47c, 47d) without inducing a current in the rotor (46) and without coupling a stator rotational energy component to the secondary coils (47c, 47d). The machine can be operated as a motor or a generator in multi-phase or single-phase embodiments and is applicable to the hybrid electric vehicle. A method of providing a slip energy controller is also disclosed.

  13. Equatorial ionospheric electric fields during the November 2004 magnetic storm

    OpenAIRE

    Fejer, Bela G.; Jensen, J. W.; Kikuchi, T.; Abdu, M. A.; Chau, J. L.

    2007-01-01

    [1] We use radar measurements from the Jicamarca Radio Observatory, magnetometer observations from the Pacific sector and ionosonde data from Brazil to study equatorial ionospheric electric fields during the November 2004 geomagnetic storm. Our data show very large eastward and westward daytime electrojet current perturbations with lifetimes of about an hour (indicative of undershielding and overshielding prompt penetration electric fields) in the Pacific equatorial region during the November...

  14. Spin magnetic moments from single atoms to small Cr clusters

    Energy Technology Data Exchange (ETDEWEB)

    Boeglin, C.; Decker, R.; Bulou, H.; Scheurer, F.; Chado, I. [IPCMS-GSI - UMR 7504, 67037 Strasbourg Cedex (France); Ohresser, P. [LURE, 91405 Orsay (France); Dhesi, S.S. [ESRF, BP 220, 38043 Grenoble Cedex (France); Present permanent address: Diamond Light Source, Chilton, Didcot OX11 0QX (United Kingdom); Gaudry, E. [LMCP, 4, place Jussieu, 75252 Paris (France); Lazarovits, B. [CCMS, T.U. Vienna, Gumpendorfstr. 1a, 1060 Wien (Austria)

    2005-07-01

    Morphology studies at the first stages of the growth of Cr/Au(111) are reported and compared to the magnetic properties of the nanostructures. We analyze by Scanning Tunneling Microscopy and Low Energy Electron Diffraction the Cr clusters growth between 200 K and 300 K. In the early stages of the growth the morphology of the clusters shows monoatomic high islands located at the kinks of the herringbone reconstructed Au(111) surface. By X-ray Magnetic Circular Dichroism performed on the Cr L{sub 2,3} edges it is shown that the temperature dependent morphology strongly influences the magnetic properties of the Cr clusters. We show that in the sub-monolayer regime Cr clusters are antiferromagnetic and paramagnetic when the size reaches the atomic limit. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Current densities in a pregnant woman model induced by simultaneous ELF electric and magnetic field exposure

    International Nuclear Information System (INIS)

    Cech, R; Leitgeb, N; Pediaditis, M

    2008-01-01

    The pregnant woman model SILVY was studied to ascertain to what extent the electric current densities induced by 50 Hz homogeneous electric and magnetic fields increase in the case of simultaneous exposure. By vectorial addition of the electric current densities, it could be shown that under worst case conditions the basic restrictions recommended by ICNIRP (International Commission on Non-Ionizing Radiation Protection) guidelines are exceeded within the central nervous system (CNS) of the mother, whereas in sole field exposure they are not. However, within the foetus the induced current densities do not comply with basic restrictions, either from single reference-level electric fields or from simultaneous exposure to electric and magnetic fields. Basic limits were considerably exceeded

  16. Static resistivity image of a cubic saline phantom in magnetic resonance electrical impedance tomography (MREIT).

    Science.gov (United States)

    Lee, Byung Il; Oh, Suk Hoon; Woo, Eung Je; Lee, Soo Yeol; Cho, Min Hyeong; Kwon, Ohin; Seo, Jin Keun; Baek, Woon Sik

    2003-05-01

    In magnetic resonance electrical impedance tomography (MREIT) we inject currents through electrodes placed on the surface of a subject and try to reconstruct cross-sectional resistivity (or conductivity) images using internal magnetic flux density as well as boundary voltage measurements. In this paper we present a static resistivity image of a cubic saline phantom (50 x 50 x 50 mm3) containing a cylindrical sausage object with an average resistivity value of 123.7 ohms cm. Our current MREIT system is based on an experimental 0.3 T MRI scanner and a current injection apparatus. We captured MR phase images of the phantom while injecting currents of 28 mA through two pairs of surface electrodes. We computed current density images from magnetic flux density images that are proportional to the MR phase images. From the current density images and boundary voltage data we reconstructed a cross-sectional resistivity image within a central region of 38.5 x 38.5 mm2 at the middle of the phantom using the J-substitution algorithm. The spatial resolution of the reconstructed image was 64 x 64 and the reconstructed average resistivity of the sausage was 117.7 ohms cm. Even though the error in the reconstructed average resistivity value was small, the relative L2-error of the reconstructed image was 25.5% due to the noise in measured MR phase images. We expect improvements in the accuracy by utilizing an MRI scanner with higher SNR and increasing the size of voxels scarifying the spatial resolution.

  17. Learning about static electricity and magnetism in a fourth-grade classroom

    Science.gov (United States)

    Henry, David Roy

    Students begin to develop mental models to explain electrostatic and magnetic phenomena throughout childhood, middle childhood and high school, although these mental models are often incoherent and unscientific (Borges, Tenico, & Gilbert, 1998; Maloney, 1985). This is a case study of a classroom of grade four students and the mental models of magnetism and static electricity they used during a six-week science unit. The 22 students studied magnetism and static electricity using inquiry activities structured to create an environment where students would be likely to construct powerful scientific ideas (Goldberg & Bendall, 1995). Multiple data sources, including students' writing, student assessments, teacher interviews, student interviews, teacher journals, and classroom video and audio recordings were used to uncover how fourth grade students made sense of static electricity and magnetism before, during, and after instruction. The data were analyzed using a social constructivist framework to determine if students were able to develop target scientific ideas about static electricity and magnetism. In general, students were found to have three core mental models prior to instruction: (1) Static electricity and magnetism are the same "substance"; (2) This substance exists on the surface of a magnet or a charged object and can be rubbed off, and (3) Opposite substances attract. During the activities, students had many opportunities to observe evidence that contradicted these core mental models. Using evidence from direct observations, the students practiced differentiating between evidence and ideas. Through group and class discussions, they developed evidenced-based (scientific) ideas. Final assessments revealed that students were able to construct target ideas such as: (1) static electricity and magnetism are fundamentally different; (2) there are two kinds of static "charge;" (3) magnet-rubbed wires act like a magnet; and (4) opposite substances move toward each

  18. Small-scale magnetic fluctuations inside the Macrotor tokamak

    International Nuclear Information System (INIS)

    Zweben, S.J.; Menyuk, C.R.; Taylor, R.J.

    1979-01-01

    Magnetic pickup loops inserted into the Macrotor tokamak have shown a broad spectrum of oscillation in B/sub r/ and B/sub p/ up to f approx. = 100 kHz. The high-frequency B/sub r/ have short radial and poloidal correlation lengths L > 5 cm. The observed magnitude summationvertical-barB/sub r/vertical-bar/B/sub T/ > 10 -5 , where the summation extends over all f > 30 kHz, is in the range in which such radial magnetic perturbations may be contributing to anomalous electron energy transport

  19. Electric Mars: A Large Trans-Terminator Electric Potential Drop on Closed Magnetic Field Lines Above Utopia Planitia

    Science.gov (United States)

    Collinson, Glyn; Mitchell, David; Xu, Shaosui; Glocer, Alex; Grebowsky, Joseph; Hara, Takuya; Lillis, Robert; Espley, Jared; Mazelle, Christian; Sauvaud, Jean-Andre

    2017-01-01

    Abstract Parallel electric fields and their associated electric potential structures play a crucial role inionospheric-magnetospheric interactions at any planet. Although there is abundant evidence that parallel electric fields play key roles in Martian ionospheric outflow and auroral electron acceleration, the fields themselves are challenging to directly measure due to their relatively weak nature. Using measurements by the Solar Wind Electron Analyzer instrument aboard the NASA Mars Atmosphere and Volatile EvolutioN(MAVEN) Mars Scout, we present the discovery and measurement of a substantial (Phi) Mars 7.7 +/-0.6 V) parallel electric potential drop on closed magnetic field lines spanning the terminator from day to night above the great impact basin of Utopia Planitia, a region largely free of crustal magnetic fields. A survey of the previous 26 orbits passing over a range of longitudes revealed similar signatures on seven orbits, with a mean potential drop (Phi) Mars of 10.9 +/- 0.8 V, suggestive that although trans-terminator electric fields of comparable strength are not ubiquitous, they may be common, at least at these northerly latitudes.

  20. Electric Mars: A large trans-terminator electric potential drop on closed magnetic field lines above Utopia Planitia

    Science.gov (United States)

    Collinson, Glyn; Mitchell, David; Xu, Shaosui; Glocer, Alex; Grebowsky, Joseph; Hara, Takuya; Lillis, Robert; Espley, Jared; Mazelle, Christian; Sauvaud, Jean-André; Fedorov, Andrey; Liemohn, Mike; Andersson, Laila; Jakosky, Bruce

    2017-02-01

    Parallel electric fields and their associated electric potential structures play a crucial role in ionospheric-magnetospheric interactions at any planet. Although there is abundant evidence that parallel electric fields play key roles in Martian ionospheric outflow and auroral electron acceleration, the fields themselves are challenging to directly measure due to their relatively weak nature. Using measurements by the Solar Wind Electron Analyzer instrument aboard the NASA Mars Atmosphere and Volatile EvolutioN (MAVEN) Mars Scout, we present the discovery and measurement of a substantial (ΦMars=7.7 ± 0.6 V) parallel electric potential drop on closed magnetic field lines spanning the terminator from day to night above the great impact basin of Utopia Planitia, a region largely free of crustal magnetic fields. A survey of the previous 26 orbits passing over a range of longitudes revealed similar signatures on seven orbits, with a mean potential drop (ΦMars) of 10.9 ± 0.8 V, suggestive that although trans-terminator electric fields of comparable strength are not ubiquitous, they may be common, at least at these northerly latitudes.

  1. Possible Future Role of Small and Medium Sized Reactors (SMRs) in Countries with Small and Medium Electricity Grids

    International Nuclear Information System (INIS)

    Alujevic, L.

    2016-01-01

    Small and Medium Sized Reactors (SMRs) could have enormous potential as options for enhancing the energy supply security, as well as providing a lower capital investment compared to conventional Nuclear Power Plants (NPPs). The trend in SMR development has been towards design certification of small modular reactors, defined as advanced reactors that produce electric power up to 300 MW(e), designed to be built in factories and shipped to utilities for installation as demand arises. The factory-built small modular reactors aim to reduce lengthy construction times while simultaneously increasing quality, thereby minimizing the costs associated with the current time for construction that spans 5 to 8 years. SMR designs include water-cooled reactors, high temperature gas cooled reactors, as well as liquid metal cooled reactors with fast neutron spectrum. Also, many are designed to be emplaced below ground level, giving a high resistance to terrorist threats. The projected timelines of readiness for deployment of SMRs generally range from the present to 2025 - 2030. Currently there are more than 45 SMR designs under development for different application issues. This paper will try to elaborate the benefits and drawbacks of SMRs, as well as describe a couple of designs. Furthermore, some timelines and cost estimates will be provided, depending on the data currently available. Taking all that into account, the conclusion will try to ascertain the suitability of SMRs for Countries with Small and Medium Electricity Grids, namely Croatia. (author).

  2. Ionospheric response to variable electric fields in small-scale auroral structures

    Directory of Open Access Journals (Sweden)

    B. S. Lanchester

    1998-10-01

    Full Text Available High time and space resolution optical and radar measurements have revealed the influence of electric fields on E-region electron density profiles in small-scale auroral structures. Large electric fields are present adjacent to auroral filaments produced by monoenergetic electron fluxes. The ionisation profiles measured within and beside the auroral filaments show the effects of plasma convection due to electric fields as well as the consequences of the response time to large and dynamic fluxes of energetic electrons. Without high-resolution optical measurements, the interpretation of the radar data is limited.Key words. Auroral ionosphere · Ionosphere-magnetosphere interactions · EISCAT

  3. Ionospheric response to variable electric fields in small-scale auroral structures

    Directory of Open Access Journals (Sweden)

    B. S. Lanchester

    Full Text Available High time and space resolution optical and radar measurements have revealed the influence of electric fields on E-region electron density profiles in small-scale auroral structures. Large electric fields are present adjacent to auroral filaments produced by monoenergetic electron fluxes. The ionisation profiles measured within and beside the auroral filaments show the effects of plasma convection due to electric fields as well as the consequences of the response time to large and dynamic fluxes of energetic electrons. Without high-resolution optical measurements, the interpretation of the radar data is limited.

    Key words. Auroral ionosphere · Ionosphere-magnetosphere interactions · EISCAT

  4. Electrical design for origami solar panels and a small spacecraft test mission

    Science.gov (United States)

    Drewelow, James; Straub, Jeremy

    2017-05-01

    Efficient power generation is crucial to the design of spacecraft. Mass, volume, and other limitations prevent the use of traditional spacecraft support structures from being suitable for the size of solar array required for some missions. Folding solar panel / panel array systems, however, present a number of design challenges. This paper considers the electrical design of an origami system. Specifically, it considers how to provide low impedance, durable channels for the generated power and the electrical aspects of the deployment system and procedure. The ability to dynamically reconfigure the electrical configuration of the solar cells is also discussed. Finally, a small satellite test mission to demonstrate the technology is proposed, before concluding.

  5. Single crystal growth and electrical and magnetic measurements on CeFe4Sb12

    International Nuclear Information System (INIS)

    Mori, I.; Sugawara, H.; Magishi, K.; Saito, T.; Koyama, K.; Kikuchi, D.; Tanaka, K.; Sato, H.

    2007-01-01

    We have succeeded in growing single crystals of CeFe 4 Sb 12 by a Sb-self-flux method and measured the electrical resistivity and magnetization. The residual resistivity is about two times smaller than that of polycrystalline ones, suggesting that the sample quality is highly improved. The magnetization measurements at low temperature revealed that the sample contains almost no magnetic impurities which are always observed in polycrystalline samples. The weak temperature dependence and a broad maximum around 115K in magnetic susceptibility, which is a typical feature of valence fluctuation compounds, have been observed

  6. Electrical resistance of flaky crystals in the longitudinal quantizing magnetic field

    International Nuclear Information System (INIS)

    Askerov, B.M.; Figarova, S.R.; Makhmudov, M.M.

    2005-01-01

    Specific resistance of the quasi-two-dimensional electrical gas in the longitudinal quantizing magnetic field is investigated in this work. Common expression for resistivity in the flaky crystals was received. In quantum limit was analyzed dependence of the resistivity from the size of magnetic field and parameters energetic spectra in case of strong degenerate gas. It was tagged that, the conduct of specific resistance is formed by the dependence of chemical potential from the size of magnetic field. At the defined value of the chemical potential and size of magnetic field obtains inflation of the specific resistance. (author)

  7. Magnetization, Magnetocrystalline Anisotropy and the Crystalline Electric Field in Rare-Earth Al2 Compounds

    DEFF Research Database (Denmark)

    Purwins, H. -G.; Walker, E.; Barbara, B.

    1974-01-01

    a quantitative quantum mechanical description of the magnetization and the related magnetocrystalline anisotropy in terms of a cubic crystalline electric field and an isotropic exchange interaction. The parameters used in this description can be unified to good approximation to all REAl2 intermetallic compounds......Magnetization measurements are reported for single crystals of PrAl2 in the range from 4.2K to 30K for magnetic fields up to 150 kOe applied in the (100), (110) and (111) directions. For these measurements, together with the magnetization results obtained earlier for TbAl2 the authors give...

  8. Radiative Decay Rates for Electric Dipole, Magnetic Dipole and Electric Quadrupole Transitions in Triply Ionized Thulium (Tm IV

    Directory of Open Access Journals (Sweden)

    Saturnin Enzonga Yoca

    2017-09-01

    Full Text Available A new set of radiative decay parameters (oscillator strengths, transition probabilities for spectral lines in triply ionized thulium (Tm IV has been obtained within the framework of the pseudo-relativistic Hartree-Fock (HFR approach. The effects of configuration interaction and core-polarization have been investigated in detail and the quality of the results has been assessed through a comparison between different HFR physical models. The spectroscopic data listed in the present paper cover electric dipole as well as magnetic dipole and electric quadrupole transitions in a wide range of wavelengths from extreme ultraviolet to near infrared.

  9. Self-Resonant Electrically Small Loop Antennas for Hearing-Aids Application

    DEFF Research Database (Denmark)

    Zhang, Jiaying; Breinbjerg, Olav

    2010-01-01

    Two novel self-resonant electrically small antennas are proposed in this paper, which are designed for hearing aids applications. They are miniaturized by using the capacitive and inductive coupling mechanism between two loops, and the antenna impedance can be matched to a specific value without...... using any additional matching network and lumped components. The dimension of the proposed antenna is 0.10λ0×0.03λ0, and it is designed to be resonant at 900 MHz. Both the analytical model and numerical simulations are discussed and explained. The antenna is also fabricated and measured in an anechoic...... chamber. The measurement methods for electrically small antennas are reported....

  10. A modified Wheeler cap method for radiation efficiency measurement of balanced electrically small antennas

    DEFF Research Database (Denmark)

    Zhang, Jiaying; Pivnenko, Sergey; Breinbjerg, Olav

    2010-01-01

    , but not for balanced antennas like loops or dipoles. In this paper, a modified Wheeler cap method is proposed for the radiation efficiency measurement of balanced electrically small antennas and a three-port network model of the Wheeler cap measurement is introduced. The advantage of the modified method...... is that it is wideband, thus does not require any balun, and both the antenna input impedance and radiation efficiency can be obtained. An electrically small loop antenna and a wideband dipole were simulated and measured according to the proposed method and the results of measurements and simulations are presented...

  11. CRIT II electric, magnetic, and density measurements within an ionizing neutral stream

    Science.gov (United States)

    Swenson, C. M.; Kelley, M. C.; Primdahl, F.; Baker, K. D.

    1990-01-01

    Measurements from rocket-borne sensors inside a high-velocity neutral barium beam show a-factor-of-six increase in plasma density in a moving ionizing front. This region was colocated with intense fluctuating electric fields at frequencies well under the lower hybrid frequency for a barium plasma. Large quasi-dc electric and magnetic field fluctuations were also detected with a large component of the current and the electric field parallel to B(0). An Alfven wave with a finite electric field component parallel to the geomagnetic field was observed to propagate along B(0), where it was detected by an instrumented subpayload.

  12. Magnetic Shielding Design for Coupler of Wireless Electric Vehicle Charging Using Finite Element Analysis

    Science.gov (United States)

    Zhao, W. N.; Yang, X. J.; Yao, C.; Ma, D. G.; Tang, H. J.

    2017-10-01

    Inductive power transfer (IPT) is a practical and preferable method for wireless electric vehicle (EV) charging which proved to be safe, convenient and reliable. Due to the air gap between the magnetic coupler, the magnetic field coupling decreases and the magnetic leakage increases significantly compared to traditional transformer, and this may lead to the magnetic flux density around the coupler more than the safety limit for human. So magnetic shielding should be adding to the winding made from litz wire to enhance the magnetic field coupling effect in the working area and reduce magnetic field strength in non-working area. Magnetic shielding can be achieved by adding high-permeability material or high-conductivity material. For high-permeability material its magnetic reluctance is much lower than the surrounding air medium so most of the magnetic line goes through the high-permeability material rather than surrounding air. For high-conductivity material the eddy current in the material can produce reverse magnetic field to achieve magnetic shielding. This paper studies the effect of the two types of shielding material on coupler for wireless EV charging and designs combination shielding made from high-permeability material and high-conductivity material. The investigation of the paper is done with the help of finite element analysis.

  13. The application of bonded magnet MQP-0 on an electrical direct current motor

    International Nuclear Information System (INIS)

    Ridwan; Mujamilah; Gunawan

    2002-01-01

    Isotropic bonded magnet materials using NdFeB produced by rapid quench method, has advantages that can be easily adapted to the costumer demand. The synthesized bonded magnets are mixed of cpoxy resin or polyester as matrix binder with powder magnet of MQP-O The proportions of polymer and magnetic powder are 4060; 50:50; and 6040 volume % of magnet composites. The characterization of magnetic properties was determined by Vibrating Sample Magnetometer (VSM) at P3IB-BATAN and the density was measured by piknometer. The highest energy product maximum, (BH) m ax of magnet composite synthesized by P3IB-BATAN in this activity is 435 MGOeThe quality of magnet components has been tested empirically by changing the magnetic components of an electric direct current motor found in the local market by magnetic components synthesized by P 3IB-BA TAN. The max imum rotation resulted by using P3IB-BATAN is 40 0 00 rpm The magnetic components synthesized in these research activities are functionally work and comparatively the same with the magnetic components found in the local market as an import commodities

  14. Armature reaction of permanent magnet-excited small dc motors with shell type magnets and possibilities of power increase

    Energy Technology Data Exchange (ETDEWEB)

    Gutt, H J; Tran, Q N

    1983-07-01

    Permanent magnet-excited small dc motors allow an increase of power up to 30% compared with present permanent excited motors. The calculation of immediate irreversible demagnetization of the air-gap situated shell type magnets is necessary for a good motor design. Numerical calculated field line plots show the critical zones of the irreversible demagnetization at high armature reaction and refer how to avoid the flux loss and to increase the motor power.

  15. Improvement of a magnetization method on a small-size superconducting bulk magnet system

    International Nuclear Information System (INIS)

    Yokoyama, K.; Oka, T.; Noto, K.

    2011-01-01

    This paper proposed an effective magnetizing method of high-T c bulk superconductors. The magnetic pass was artificially formed by field-cooling using a permanent magnet. The trapped field was increased by 20-25% as compared with the conventional method. We observed that the channel was formed partially in the trapped field distribution. A pulsed-filed magnetization (PFM) is an important technique for industrial applications of superconducting bulk magnets, and several advanced PFM methods are proposed to enhance the trapped field. In the well-known IMRA method, the channel through the magnetic flux is formed by the flux flow caused by heat generation when applying the strong pulsed-field, and the magnetic flux is made to penetrate into the bulk through the channel in the following pulse application. On the other hand, large applied field leads to large heat generation, and, therefore, the trapped field is decreased greatly. This paper proposes an effective magnetizing method in which the channel composed of magnetic field is artificially formed by field-cooling (FC) using a permanent magnet and the magnetic flux by PFM is induced to the channel. To confirm the validity of this method, the bulk was magnetized by FC using Nd-Fe-B magnets of the rectangular and the ring shapes, and thereafter, a pulsed-field of 6.2 T was applied. As a result, the trapped field of the bulk magnetized by FC using the ring magnet was increased by about 20-25% as compared with that of the conventional PFM, and, moreover, it was observed that the channel was formed partially by measurement of the magnetic field distribution.

  16. Small magnetic energy storage systems using high temperature superconductors

    International Nuclear Information System (INIS)

    Kumar, B.

    1991-01-01

    This paper reports on magnetic energy storage for power systems that has been considered for commercial utility power, air and ground mobile power sources, and spacecraft applications. Even at the current technology limits of energy storage (100 KJ/Kg*), superconducting magnetic energy storage inductors do not offer a strong advantage over state-of-the-art batteries. The commercial utility application does not have a weight and volume limitation, and is under intense study in several countries for diurnal cycle energy storage and high power delivery. The advent of high temperature superconductors has reduced one of the penalties of superconducting magnetic energy storage in that refrigeration and cryocontainers become greatly simplified. Still, structural and current density issues that limit the energy density and size of superconducting inductors do not change. Cold weather starting of aircraft engines is an application where these limitations are not as significant, and where current systems lack performance. The very cold environments make it difficult to achieve high power densities in state-of-the-art batteries and hydraulically activated starters. The same cold environments make it possible to cool superconducting systems for weeks using a single charge of liquid nitrogen. At the same, the ground carts can handle the size and weight of superconducting magnetic storage (SMES) devices

  17. Influence of the mechanical fatigue progress on the magnetic properties of electrical steel sheets

    Directory of Open Access Journals (Sweden)

    Karthaus Jan

    2017-06-01

    Full Text Available The purpose of this paper is to study the variation of the magnetic properties of non-oriented electrical steel sheets with the fatigue state during cyclic mechanical loading. The obtained results are central to the design of variable drives such as traction drives in electric vehicles in which varying mechanical loads, e.g. in the rotor core (centrifugal forces, alter the magnetic properties. Specimens of non-oriented electrical steel are subject to a cyclically varying mechanical tensile stress with different stress amplitudes and number of cycles. The specimens are characterised magnetically at different fatigue states for different magnetic flux densities and magnetising frequencies. The measurements show a variation in magnetic properties depending on the number of cycles and stress magnitude which can be explained by changes in the material structure due to a beginning mechanical fatigue process. The studied effect is critical for the estimation of the impact of mechanical material fatigue on the operational behaviour of electrical machines. Particularly in electrical machines with a higher speed where the rotor is stressed by high centrifugal forces, material fatigue occurs and can lead to deterioration of the rotor’s stack lamination.

  18. Methods for the improvement of electrical insulation in vacuum in the presence of transverse magnetic field

    International Nuclear Information System (INIS)

    Hara, Masanori; Suehiro, Junya; Shigematsu, Hidetaka; Yano, Shinsuke

    1989-01-01

    At present in electrical energy field, aiming at the development and operation of new energy sources for the future, the research on nuclear fusion reactors, MHD electricity generation, and electromagnetic energy storage is in progress, and in ordeer to form strong magnetic fields over wide space, large superconducting magnets are expected to be employed. In these magnets, when exciting current changes, voltage is induced internally, therefore, the operation sequence is deeply related to coil insulation, in pulse operation, coil insulation is one of the important factors determining the rating, and the withstand voltage design against the abnormal voltage at the time of quenching is related to the protection of coils. Therefore, the electrical insulation design of large superconducting magnets is an important subject of study. Their electrical insulation system is the compound system of liquid helium, gaseous helium, vacuum and solid insulators. When a cross magnetic field is applied, insulation breakdown characteristics are aggravated. The mechanism of vacuum insulation breakdown and characteristics, the method of improving withstand voltage using spacers or the electrodes for controlling electric field and so on are reported. (K.I.)

  19. [Occupational exposure of physical therapists to electric and magnetic fields and the efficacy of Faraday cages].

    Science.gov (United States)

    Messias, Iracimara de Anchieta; Okuno, Emico; Colacioppo, Sérgio

    2011-10-01

    Measure physical therapists' exposure to the electric and magnetic fields produced by 17 shortwave diathermy devices in physical therapy clinics in the city of Presidente Prudente, São Paulo State, Brazil. Compare the observed values with the exposure levels recommended by the International Commission on Non-ionizing Radiation Protection (ICNIRP). Observe the efficacy of Faraday cages as a means of protecting physical therapists from exposure to oscillating electric and magnetic fields. Electric and magnetic field measurements were taken at four points during actual physical therapy sessions: in proximity to the operator's pelvis and head, the devices' electrical cables, and the electrodes. The measuring equipment was a Wandel & Goltermann EMR-200. The values obtained in proximity to the electrodes and cables were 10 to 30 times higher than ICNIRP's recommended occupational reference levels. In the shortwave diathermy treatment rooms with Faraday cages, the fields were even higher than in treatment rooms not so equipped-principally the magnetic field, where the values were more than 100 times higher than the ICNIRP exposure limit. The electric and magnetic field intensities obtained in this study are generally above the exposure levels recommend in ICNIRP standards. It was also observed that the Faraday cage offers physical therapists no protection, and instead, increases their level of exposure.

  20. MAGNET

    CERN Multimedia

    Benoit Curé.

    The magnet operation restarted end of June this year. Quick routine checks of the magnet sub-systems were performed at low current before starting the ramps up to higher field. It appeared clearly that the end of the field ramp down to zero was too long to be compatible with the detector commissioning and operations plans. It was decided to perform an upgrade to keep the ramp down from 3.8T to zero within 4 hours. On July 10th, when a field of 1.5T was reached, small movements were observed in the forward region support table and it was decided to fix this problem before going to higher field. At the end of July the ramps could be resumed. On July 28th, the field was at 3.8T and the summer CRAFT exercise could start. This run in August went smoothly until a general CERN wide power cut took place on August 3rd, due to an insulation fault on the high voltage network outside point 5. It affected the magnet powering electrical circuit, as it caused the opening of the main circuit breakers, resulting in a fast du...

  1. Effect of elastic and plastic tensile mechanical loading on the magnetic properties of NGO electrical steel

    Energy Technology Data Exchange (ETDEWEB)

    Leuning, N., E-mail: nora.leuning@iem.rwth-aachen.de [Institute of Electrical Machines, RWTH Aachen University, D-52062 Aachen (Germany); Steentjes, S. [Institute of Electrical Machines, RWTH Aachen University, D-52062 Aachen (Germany); Schulte, M.; Bleck, W. [Steel Institute, RWTH Aachen University, D-52072 Aachen (Germany); Hameyer, K. [Institute of Electrical Machines, RWTH Aachen University, D-52062 Aachen (Germany)

    2016-11-01

    The magnetic properties of non-grain-oriented (NGO) electrical steels are highly susceptible to mechanical stresses, i.e., residual, external or thermal ones. For rotating electrical machines, mechanical stresses are inevitable and originate from different sources, e.g., material processing, machine manufacturing and operating conditions. The efficiency and specific losses are largely altered by different mechanical stress states. In this paper the effect of tensile stresses and plastic deformations on the magnetic properties of a 2.9 wt% Si electrical steel are studied. Particular attention is paid to the effect of magnetic anisotropy, i.e., the influence of the direction of applied mechanical stress with respect to the rolling direction. Due to mechanical stress, the induced anisotropy has to be evaluated as it is related to the stress-dependent magnetostriction constant and the grain alignment. - Highlights: • A detailed look at magnetic anisotropy of FeSi NGO electrical steel. • Study of magnetic behavior under elastic as well as plastic tensile stresses. • Correlation of magnetic behavior with microscopic deformation mechanisms. • Discussion of detrimental and beneficial effects of external stresses. • Loss separation at different polarizations and frequencies under increasing stress.

  2. Generation of macroscopic magnetic-field-aligned electric fields by the convection surge ion acceleratiom mechanism

    International Nuclear Information System (INIS)

    Mauk, B.H.

    1989-01-01

    The ''convection surge'' computer model presented previously (concerning the dramatic, nonadiabatic, magnetic-field-aligned energization of ions near the Earth's geosynchronous orbit in the presence of strong, transient, magnetic-field-perpendicular inductive electric fields) has been extended to include the self-consistent generation of magnetic-field-aligned electric fields. The field-aligned electric potential is obtained by imposing the quasi-neutrality condition using approximated electron distribution forms. The ions are forced to respond self-consistently to this potential. It is found that field-aligned potential drops up to 1 to 10 kV can be generated depending on electron temperatures and on the mass species of the ions. During transient periods of the process, these large potential drops can be confined to a few degrees of magnetic latitude at positions close to the magnetic equator. Anomalous, sometimes dramatic, additional magnetic-field-aligned ion acceleration also occurs in part as a result of a quasi-resonance between the parallel velocities of some ions and the propagating electric potential fronts. It is speculated that the convection surge mechanism could be a key player in the transient, field-aligned electromagnetic processes observed to operate within the middle (e.g., geosynchronous) magnetosphere. copyright American Geophysical Union 1989

  3. Effect of elastic and plastic tensile mechanical loading on the magnetic properties of NGO electrical steel

    International Nuclear Information System (INIS)

    Leuning, N.; Steentjes, S.; Schulte, M.; Bleck, W.; Hameyer, K.

    2016-01-01

    The magnetic properties of non-grain-oriented (NGO) electrical steels are highly susceptible to mechanical stresses, i.e., residual, external or thermal ones. For rotating electrical machines, mechanical stresses are inevitable and originate from different sources, e.g., material processing, machine manufacturing and operating conditions. The efficiency and specific losses are largely altered by different mechanical stress states. In this paper the effect of tensile stresses and plastic deformations on the magnetic properties of a 2.9 wt% Si electrical steel are studied. Particular attention is paid to the effect of magnetic anisotropy, i.e., the influence of the direction of applied mechanical stress with respect to the rolling direction. Due to mechanical stress, the induced anisotropy has to be evaluated as it is related to the stress-dependent magnetostriction constant and the grain alignment. - Highlights: • A detailed look at magnetic anisotropy of FeSi NGO electrical steel. • Study of magnetic behavior under elastic as well as plastic tensile stresses. • Correlation of magnetic behavior with microscopic deformation mechanisms. • Discussion of detrimental and beneficial effects of external stresses. • Loss separation at different polarizations and frequencies under increasing stress.

  4. Investigation on magnetoacoustic signal generation with magnetic induction and its application to electrical conductivity reconstruction

    International Nuclear Information System (INIS)

    Ma Qingyu; He Bin

    2007-01-01

    A theoretical study on the magnetoacoustic signal generation with magnetic induction and its applications to electrical conductivity reconstruction is conducted. An object with a concentric cylindrical geometry is located in a static magnetic field and a pulsed magnetic field. Driven by Lorentz force generated by the static magnetic field, the magnetically induced eddy current produces acoustic vibration and the propagated sound wave is received by a transducer around the object to reconstruct the corresponding electrical conductivity distribution of the object. A theory on the magnetoacoustic waveform generation for a circular symmetric model is provided as a forward problem. The explicit formulae and quantitative algorithm for the electrical conductivity reconstruction are then presented as an inverse problem. Computer simulations were conducted to test the proposed theory and assess the performance of the inverse algorithms for a multi-layer cylindrical model. The present simulation results confirm the validity of the proposed theory and suggest the feasibility of reconstructing electrical conductivity distribution based on the proposed theory on the magnetoacoustic signal generation with magnetic induction

  5. University students' conceptions of the electric and magnetic fields and their interrelationships

    International Nuclear Information System (INIS)

    Kesonen, M H P; Asikainen, M A; Hirvonen, P E

    2011-01-01

    This study focuses on students' conceptions of electric and magnetic fields at university level and of the interrelations between them. A total of 33 students participated in a paper and pencil test after the completion of first-year electricity and second-year electromagnetism courses. The conceptions were investigated in the contexts of a charged particle, a charging capacitor, electromagnetic induction, and an electromagnetic plane wave. The results show that students do not include the vector nature of field quantities in their reasoning. In addition, learning the interactions between electric and magnetic fields is very challenging for university students. Even after completing relevant studies, the students had difficulty in recognizing the symmetry relations between the electric and magnetic fields in all of the areas under study. Consequently, it appears that the concepts of electric and magnetic fields and their interrelations should be emphasized not only in the context of electromagnetism but also in other relevant areas such as electricity and optics. Explicit recommendations are presented in the discussion section at the end of this paper.

  6. Control of magnetism in Co by an electric field

    Science.gov (United States)

    Chiba, D.; Ono, T.

    2013-05-01

    In this paper, we review the recent experimental developments on electric-field switching of ferromagnetism in ultra-thin Co films. The application of an electric field changes the electron density at the surface of the Co film, which results in modulation of its Curie temperature. A capacitor structure consisting of a gate electrode, a solid-state dielectric insulator and a Co bottom electrode is used to observe the effect. To obtain a larger change in the electron density, we also fabricated an electric double-layer capacitor structure using an ionic liquid. A large change in the Curie temperature of ∼100 K across room temperature is achieved with this structure. The application of the electric field influences not only the Curie temperature but also the domain-wall motion. A change in the velocity of a domain wall prepared in a Co micro-wire of more than one order of magnitude is observed. Possible mechanisms to explain the above-mentioned electric-field effects in Co ultra-thin films are discussed.

  7. Control of magnetism in Co by an electric field

    International Nuclear Information System (INIS)

    Chiba, D; Ono, T

    2013-01-01

    In this paper, we review the recent experimental developments on electric-field switching of ferromagnetism in ultra-thin Co films. The application of an electric field changes the electron density at the surface of the Co film, which results in modulation of its Curie temperature. A capacitor structure consisting of a gate electrode, a solid-state dielectric insulator and a Co bottom electrode is used to observe the effect. To obtain a larger change in the electron density, we also fabricated an electric double-layer capacitor structure using an ionic liquid. A large change in the Curie temperature of ∼100 K across room temperature is achieved with this structure. The application of the electric field influences not only the Curie temperature but also the domain-wall motion. A change in the velocity of a domain wall prepared in a Co micro-wire of more than one order of magnitude is observed. Possible mechanisms to explain the above-mentioned electric-field effects in Co ultra-thin films are discussed. (topical review)

  8. Long-duration transcutaneous electric acupoint stimulation alters small-world brain functional networks.

    Science.gov (United States)

    Zhang, Yue; Jiang, Yin; Glielmi, Christopher B; Li, Longchuan; Hu, Xiaoping; Wang, Xiaoying; Han, Jisheng; Zhang, Jue; Cui, Cailian; Fang, Jing

    2013-09-01

    Acupuncture, which is recognized as an alternative and complementary treatment in Western medicine, has long shown efficiencies in chronic pain relief, drug addiction treatment, stroke rehabilitation and other clinical practices. The neural mechanism underlying acupuncture, however, is still unclear. Many studies have focused on the sustained effects of acupuncture on healthy subjects, yet there are very few on the topological organization of functional networks in the whole brain in response to long-duration acupuncture (longer than 20 min). This paper presents a novel study on the effects of long-duration transcutaneous electric acupoint stimulation (TEAS) on the small-world properties of brain functional networks. Functional magnetic resonance imaging was used to construct brain functional networks of 18 healthy subjects (9 males and 9 females) during the resting state. All subjects received both TEAS and minimal TEAS (MTEAS) and were scanned before and after each stimulation. An altered functional network was found with lower local efficiency and no significant change in global efficiency for healthy subjects after TEAS, while no significant difference was observed after MTEAS. The experiments also showed that the nodal efficiencies in several paralimbic/limbic regions were altered by TEAS, and those in middle frontal gyrus and other regions by MTEAS. To remove the psychological effects and the baseline, we compared the difference between diffTEAS (difference between after and before TEAS) and diffMTEAS (difference between after and before MTEAS). The results showed that the local efficiency was decreased and that the nodal efficiencies in frontal gyrus, orbitofrontal cortex, anterior cingulate gyrus and hippocampus gyrus were changed. Based on those observations, we conclude that long-duration TEAS may modulate the short-range connections of brain functional networks and also the limbic system. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Structural, magnetic and electrical properties of ferromagnetic/ferroelectric multilayers

    International Nuclear Information System (INIS)

    Sirena, M.; Kaul, E.; Guimpel, J.; Steren, L. B.; Pedreros, M. B.; Rodriguez, C. A.

    2011-01-01

    The La 0.75 Sr 0.25 MnO 3 (LSMO)/Ba 0.7 Sr 0.3 TiO 3 (BSTO) superlattices and bilayers, where LSMO is ferromagnetic and BSTO is ferroelectric, were grown by dc sputtering. X-ray diffraction indicates that the samples present a textured growth with the c axis perpendicular to the substrate. Magnetization measurements show a decrease of the sample's magnetization for decreasing ferromagnetic thickness. This effect could be related to the presence of biaxial strain and a magnetic dead layer in the samples. Conductive atomic force microscopy indicates that the samples present a total covering of the ferromagnetic layer for a ferroelectric thickness higher than four unit cells. Transport tunneling of the carriers seems to be the preferred conduction mechanism through the ferroelectric layer. These are promising results for the development of multiferroic tunnel junctions.

  10. Modeling, design and experimental validation of a small-sized magnetic gear

    NARCIS (Netherlands)

    Zanis, R.; Borisavljevic, A.; Jansen, J.W.; Lomonova, E.A.

    2013-01-01

    A magnetostatic analytical model is created to analyze and design a small-sized magnetic gear for a robotic application. Through a parameter variation study, it is found that the inner rotor magnet height is highly influential to the torque, and based on which, the design is performed. Several

  11. Energy transfers and magnetic energy growth in small-scale dynamo

    KAUST Repository

    Kumar, Rohit Raj; Verma, Mahendra K.; Samtaney, Ravi

    2013-01-01

    In this letter we investigate the dynamics of magnetic energy growth in small-scale dynamo by studying energy transfers, mainly energy fluxes and shell-to-shell energy transfers. We perform dynamo simulations for the magnetic Prandtl number Pm = 20

  12. Superconducting Electric Machine with Permanent Magnets and Bulk HTS Elements

    Science.gov (United States)

    Levin, A. V.; Vasich, P. S.; Dezhin, D. S.; Kovalev, L. K.; Kovalev, K. L.; Poltavets, V. N.; Penkin, V. T.

    Theoretical methods of calculating of two-dimensional magnetic fields, inductive parameters and output characteristics of the new type of high-temperature superconducting (HTS) synchronous motors with a composite rotor are presented. The composite rotor has the structure containing HTS flat elements, permanent magnets and ferromagnetic materials. The developed calculation model takes into account the concentrations and physical properties of these rotor elements. The simulation results of experimental HTS motor with a composite rotor are presented. The application of new type of HTS motor in different constructions of industrial high dynamic drivers is discussed.

  13. Development of a Hybrid Piezo Natural Rubber Piezoelectricity and Piezoresistivity Sensor with Magnetic Clusters Made by Electric and Magnetic Field Assistance and Filling with Magnetic Compound Fluid.

    Science.gov (United States)

    Shimada, Kunio; Saga, Norihiko

    2017-02-10

    Piezoelements used in robotics require large elasticity and extensibility to be installed in an artificial robot skin. However, the piezoelements used until recently are vulnerable to large forces because of the thin solid materials employed. To resolve this issue, we utilized a natural rubber and applied our proposed new method of aiding with magnetic and electric fields as well as filling with magnetic compound fluid (MCF) and doping. We have verified the piezoproperties of the resulting MCF rubber. The effect of the created magnetic clusters is featured in a new two types of multilayered structures of the piezoelement. By measuring the piezoelectricity response to pressure, the synergetic effects of the magnetic clusters, the doping and the electric polymerization on the piezoelectric effect were clarified. In addition, by examining the relation between the piezoelectricity and the piezoresistivity created in the MCF piezo element, we propose a hybrid piezoelement.

  14. Development of a Hybrid Piezo Natural Rubber Piezoelectricity and Piezoresistivity Sensor with Magnetic Clusters Made by Electric and Magnetic Field Assistance and Filling with Magnetic Compound Fluid

    Science.gov (United States)

    Shimada, Kunio; Saga, Norihiko

    2017-01-01

    Piezoelements used in robotics require large elasticity and extensibility to be installed in an artificial robot skin. However, the piezoelements used until recently are vulnerable to large forces because of the thin solid materials employed. To resolve this issue, we utilized a natural rubber and applied our proposed new method of aiding with magnetic and electric fields as well as filling with magnetic compound fluid (MCF) and doping. We have verified the piezoproperties of the resulting MCF rubber. The effect of the created magnetic clusters is featured in a new two types of multilayered structures of the piezoelement. By measuring the piezoelectricity response to pressure, the synergetic effects of the magnetic clusters, the doping and the electric polymerization on the piezoelectric effect were clarified. In addition, by examining the relation between the piezoelectricity and the piezoresistivity created in the MCF piezo element, we propose a hybrid piezoelement. PMID:28208625

  15. Development of a Hybrid Piezo Natural Rubber Piezoelectricity and Piezoresistivity Sensor with Magnetic Clusters Made by Electric and Magnetic Field Assistance and Filling with Magnetic Compound Fluid

    Directory of Open Access Journals (Sweden)

    Kunio Shimada

    2017-02-01

    Full Text Available Piezoelements used in robotics require large elasticity and extensibility to be installed in an artificial robot skin. However, the piezoelements used until recently are vulnerable to large forces because of the thin solid materials employed. To resolve this issue, we utilized a natural rubber and applied our proposed new method of aiding with magnetic and electric fields as well as filling with magnetic compound fluid (MCF and doping. We have verified the piezoproperties of the resulting MCF rubber. The effect of the created magnetic clusters is featured in a new two types of multilayered structures of the piezoelement. By measuring the piezoelectricity response to pressure, the synergetic effects of the magnetic clusters, the doping and the electric polymerization on the piezoelectric effect were clarified. In addition, by examining the relation between the piezoelectricity and the piezoresistivity created in the MCF piezo element, we propose a hybrid piezoelement.

  16. Effect of crystallographic texture on the bulk magnetic properties of non-oriented electrical steels

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Pampa, E-mail: pampaghosh@gmail.com [Department of Mining and Materials Engineering, McGill University, 3610 University Street, Montreal, Quebec, Canada H3A 0C5 (Canada); Chromik, Richard R., E-mail: richard.chromik@mcgill.ca [Department of Mining and Materials Engineering, McGill University, 3610 University Street, Montreal, Quebec, Canada H3A 0C5 (Canada); Vashegi, Babak; Knight, Andrew M. [Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada T6G 2V4 (Canada)

    2014-09-01

    Quantitative physical models for non-oriented electrical steels require precise knowledge of chemical and microstructural parameters for the material, with crystallographic texture being one of the most important. Describing the structure–property relationships in these materials is made difficult in that all of the parameters have an effect on magnetic properties. In the present study, a set of non-oriented electrical steel specimens are examined, where chemistry and grain size are kept similar from sample to sample, but texture is varied. A new texture parameter called Magnetic Texture Factor is introduced which is defined as the ratio of the volume fractions of 〈100〉 direction to 〈111〉 direction along magnetization vector. It was found that this Magnetic Texture Factor was a better parameter for identifying trends of magnetic properties with crystallographic texture than the often used Texture Factor, which is described as the ratio of the volume fractions of {100} planes to {111} planes. - Highlights: • Magnetic properties of a set of electrical steels were measured. • The effect of crystallographic texture was isolated from other material parameters. • A new texture factor is introduced called the Magnetic Texture Factor.

  17. Effect of chromium concentration on the structural, magnetic and electrical properties of praseodymium-calcium manganite

    Energy Technology Data Exchange (ETDEWEB)

    Bettaibi, A. [Laboratoire de Physique des Matériaux et des Nanomatériaux appliquée à l' Environnement, Faculté des Sciences de Gabès cité Erriadh, Université de Gabès, 6079 Gabès (Tunisia); M' nassri, R., E-mail: rafik_mnassri@yahoo.fr [Higher Institute of Applied Sciences and Technology of Kasserine, Kairouan University, B.P. 471, 1200 Kasserine (Tunisia); Laboratoire de Physico-Chimie des Matériaux, Département de Physique, Faculté des Sciences de Monastir, Université de Monastir, 5019 Monastir (Tunisia); Selmi, A. [Laboratory of Physics of Materials, Faculty of Sciences of Sfax, Sfax University, B.P.1171, 3000 Sfax (Tunisia); Rahmouni, H. [Laboratoire de Physique des Matériaux et des Nanomatériaux appliquée à l' Environnement, Faculté des Sciences de Gabès cité Erriadh, Université de Gabès, 6079 Gabès (Tunisia); Chniba-Boudjada, N. [Institut NEEL, B.P.166, 38042 Grenoble Cedex 09 (France); Faculté des Sciences de Gabès cité Erriadh, Université de Gabès, 6079 Gabès (Tunisia); and others

    2015-11-25

    The influence of Cr doping on magnetic, magnetocaloric and electrical properties in a polycrystalline sample of Pr{sub 0.7}Ca{sub 0.3}MnO{sub 3} is investigated. Structural studies show that our samples are single phase. The magnetization shows that the Pr{sub 0.7}Ca{sub 0.3}Mn{sub 1−x}Cr{sub x}O{sub 3} ceramics exhibit a paramagnetic–ferromagnetic transition with a large magnetic entropy change. The relative cooling power (RCP) values are comparable to those of other manganite. DC conductance G{sub DC} measurements show that all samples are characterized by a semiconductor behavior. It is found that G{sub DC} decreases by two decades when increasing chromium concentrations. For the parent compound, dc-conductance is characterized by the appearance of a saturation region at a specific temperature (T{sub sat} = 200 K). For the doped compound, T{sub sat} go beyond room temperature. Conduction mechanism is found to be dominated by the small polaron hopping (SPH) process at high temperature and by variable range hopping one (VRH) at low temperature. AC conductance study confirms that the conductivity is governed by hopping process and obeys to the Jonscher universal power law. The exponent ‘n’ variation with temperature is in good agreement with Mott theory. Its variation as a function of chromium content indicates that the material turns from metallic to semi-insulating behavior when chromium composition increases. Impedance analysis proves the presence of electrical relaxation phenomenon in the material and confirms that grain boundaries played a main role in the conduction process. - Highlights: • Pr{sub 0.7}Ca{sub 0.3}Mn{sub 1−x}Cr{sub x}O{sub 3} manganites phases crystallize in an orthorhombic (Pnma) structure. • Pr{sub 0.7}Ca{sub 0.3}Mn{sub 0.95}Cr{sub 0.05}O{sub 3} has the highest relative cooling power. • DC conductivity measurement indicates that samples have a semiconductor character. • Conduction mechanism is well described by hopping

  18. Electrical and Magnetic Properties of Polyvinyl Alcohol-Cobalt ...

    Indian Academy of Sciences (India)

    7

    synthesis methods of shape, size, magnetic properties of cobalt ferrite ... substance was then ground into a fine powder and calcined at 600oC for 10 hours and .... From the particles distribution pattern of CFO nanoparticles in Figure 2(a), it is.

  19. Superconducting magnetic energy storage for asynchronous electrical systems

    Science.gov (United States)

    Boenig, Heinrich J.

    1986-01-01

    A superconducting magnetic energy storage coil connected in parallel between converters of two or more ac power systems provides load leveling and stability improvement to any or all of the ac systems. Control is provided to direct the charging and independently the discharging of the superconducting coil to at least a selected one of the ac power systems.

  20. Combined tangential-normal vector elements for computing electric and magnetic fields

    International Nuclear Information System (INIS)

    Sachdev, S.; Cendes, Z.J.

    1993-01-01

    A direct method for computing electric and magnetic fields in two dimensions is developed. This method determines both the fields and fluxes directly from Maxwell's curl and divergence equations without introducing potential functions. This allows both the curl and the divergence of the field to be set independently in all elements. The technique is based on a new type of vector finite element that simultaneously interpolates to the tangential component of the electric or the magnetic field and the normal component of the electric or magnetic flux. Continuity conditions are imposed across element edges simply by setting like variables to be the same across element edges. This guarantees the continuity of the field and flux at the mid-point of each edge and that for all edges the average value of the tangential component of the field and of the normal component of the flux is identical

  1. On distortions of TPC coordinates: inhomogeneities of electric and magnetic field

    CERN Document Server

    Dydak, F

    2003-01-01

    After a general discussion of electron drift in a gas volume with electric and magnetic fields, distortions in the r and r phi coordinates arising from inhomogeneities of the electric and magnetic fields in the HARP TPC are calculated. Inhomogeneities of the electric field arise from i) positive ions released by cosmic rays, ii) positive ions released by interaction secondaries, iii) positive ions released by beam muons, iv) positive ions released from beam particles downstream of the inner field cage, and v) a high voltage misalignment between the outer and inner field cages. Also, distortions arising from the inhomogeneity of the magnetic field are calculated. These effects resolve the controversy on unphysical numbers of 'wrong-charge' TPC tracks. The bad news are that effects are too big to be neglected. The good news are that, with enough sweat and tears, they can be adequately corrected.

  2. Effects of electric field and magnetic induction on spin injection into organic semiconductors

    International Nuclear Information System (INIS)

    Wang, Y.M.; Ren, J.F.; Yuan, X.B.; Dou, Z.T.; Hu, G.C.

    2011-01-01

    Spin-polarized injection and transport into ferromagnetic/organic semiconductor structure are studied theoretically in the presence of the external electric field and magnetic induction. Based on the spin-drift-diffusion theory and Ohm's law, we obtain the charge current polarization, which takes into account the special carriers of organic semiconductors. From the calculation, it is found that the current spin polarization is enhanced by several orders of magnitude by tuning the magnetic induction and electric fields. To get an apparent current spin polarization, the effects of spin-depended interfacial resistances and the special carriers in the organic semiconductor, which are polarons and bipolarons, are also discussed. -- Research highlights: → Current polarization in ferromagnetic/organic semiconductor structure is obtained. → Calculations are based on spin-drift-diffusion theory and Ohm's law. → Current polarization is enhanced by tuning magnetic induction and electric fields. → Effects of interfacial resistances and the special carriers are also discussed.

  3. Spontaneous electric polarization in the B-site magnetic spinel GeCu2O4

    Science.gov (United States)

    Yanda, Premakumar; Ghara, Somnath; Sundaresan, A.

    2018-04-01

    We report the observation of a spontaneous electric polarization at the antiferromagnetic ordering temperature (TN ∼ 33 K) of Cu2+ ions in the B-site magnetic spinel GeCu2O4, synthesized at high pressure and high temperature. This compound is known to crystallize in a tetragonal structure (space group I41/amd) due to Jahn-Teller distortion of Cu2+ ions and exhibit a collinear up-up-down-down (↑↑↓↓) antiferromagnetic spin configuration below TN. We found a clear dielectric anomaly at TN, where an electric polarization appears in the absence of applied magnetic field. The electric polarization is suppressed by applied magnetic fields, which demonstrates that the compound GeCu2O4 is a type-II multiferroic.

  4. Low losses left-handed materials with optimized electric and magnetic resonance

    Science.gov (United States)

    Zhou, Xin; Liu, Yahong; Zhao, Xiaopeng

    2010-03-01

    We propose that the losses in left-handed materials (LHMs) can be significantly affected by changing the coupling relationship between electric and magnetic resonance. A double bowknot shaped structure (DBS) is used to construct the LHMs. And the magnetic resonance of the DBS, which resonated in the case of lower and higher frequencies than the electric resonant dip, is studied in simulation and experiment by tailoring the structural parameters. The case of magnetic resonance located at low electric resonance frequencies band is confirmed to have relatively low losses. Using full wave simulation of prism shaped structure composed of DBS unit cells, we prove the negative refraction behavior in such a frame. This study can serve as a guide for designing other similar metal-dielectric-metal (MDM) in low losses at terahertz or higher frequencies.

  5. Photodetachment of H ion in crossed gradient electric and magnetic ...

    Indian Academy of Sciences (India)

    2016-10-13

    Oct 13, 2016 ... ion in a gradient electric field, the Hamiltonian of the detached electron has three degrees of freedom, which makes the dynamical behaviour of the detached electron complex. Photodetachment cross-section for vari- ous external fields and the laser polarization are calculated and displayed. A comparison ...

  6. “Surprise Gift” Purchases of Small Electric Appliances: A Pilot Study

    NARCIS (Netherlands)

    J. Vanhamme (Joëlle); C.J.P.M. de Bont (Cees)

    2005-01-01

    textabstractUnderstanding decision-making processes for gifts is of strategic importance for companies selling small electrical appliances as gifts account for a large part of their sales. Among all gifts, the ones that are surprising are the most valued by recipients. However, research about

  7. Small Wind Electric Systems: A North Carolina Consumer's Guide

    Energy Technology Data Exchange (ETDEWEB)

    2005-03-01

    Small Wind Electric Systems: A North Carolina Consumer's Guide provides consumers with information to help them determine whether a small wind electric system can provide all or a portion of the energy they need for their home or business based on their wind resource, energy needs, and their economics. Topics discussed in the guide include how to make a home more energy efficient, how to choose the correct turbine size, the parts of a wind electric system, how to determine whether enough wind resource exists, how to choose the best site for a turbine, how to connect a system to the utility grid, and whether it's possible to become independent of the utility grid using wind energy. In addition, the cover of the guide contains a list of contacts for more information.

  8. Transport coefficients for electrons in argon in crossed electric and magnetic rf fields

    International Nuclear Information System (INIS)

    Raspopovic, Z M; Dujko, S; Makabe, T; Petrovic, Z Lj

    2005-01-01

    Monte Carlo simulations of electron transport have been performed in crossed electric and magnetic rf fields in argon. It was found that a magnetic field strongly affects electron transport, producing complex behaviour of the transport coefficients that cannot be predicted on the basis of dc field theory. In particular, it is important that a magnetic field, if it has sufficiently high amplitude, allows energy gain from the electric field only over a brief period of time, which leads to a pulse of directed motion and consequently to cyclotron oscillations being imprinted on the transport coefficients. Furthermore, this may lead to negative diffusion. The behaviour of drift velocities is also interesting, with a linear (sawtooth) dependence for the perpendicular drift velocity and bursts of drift for the longitudinal. Non-conservative effects are, on the other hand, reduced by the increasing magnetic field

  9. Pair-breaking effects by parallel magnetic field in electric-field-induced surface superconductivity

    International Nuclear Information System (INIS)

    Nabeta, Masahiro; Tanaka, Kenta K.; Onari, Seiichiro; Ichioka, Masanori

    2016-01-01

    Highlights: • Zeeman effect shifts superconducting gaps of sub-band system, towards pair-breaking. • Higher-level sub-bands become normal-state-like electronic states by magnetic fields. • Magnetic field dependence of zero-energy DOS reflects multi-gap superconductivity. - Abstract: We study paramagnetic pair-breaking in electric-field-induced surface superconductivity, when magnetic field is applied parallel to the surface. The calculation is performed by Bogoliubov-de Gennes theory with s-wave pairing, including the screening effect of electric fields by the induced carriers near the surface. Due to the Zeeman shift by applied fields, electronic states at higher-level sub-bands become normal-state-like. Therefore, the magnetic field dependence of Fermi-energy density of states reflects the multi-gap structure in the surface superconductivity.

  10. Manufacturing inspection of electrical steels using Magnetic Barkhausen Noise: residual stress detection

    Energy Technology Data Exchange (ETDEWEB)

    Samimi, A.A., E-mail: 9aa8@queensu.ca [Queen' s Univ., Applied Magnetics Group, Kingston, Ontario (Canada); Krause, T.W. [Royal Military College of Canada, NDE Lab., Kingston, Ontario (Canada); Clapham, L. [Queen' s Univ., Applied Magnetics Group, Kingston, Ontario (Canada); Gallaugher, M.; Ding, Y.; Chromik, R. [McGill Univ., Dept. of Mining and Materials Engineering, Montreal, Quebec (Canada)

    2016-09-15

    Non-oriented Electrical Steel (NOES) is the magnetic core lamination material used for flux transfer in rotary machines. The presence of residual stress associated with material processing may be detrimental to magnetic domain structure refinement and as a result, magnetic performance of NOES. Therefore, manufacturing inspection of NOES that identifies the presence of residual stress could contribute to the production of more energy efficient cores. However, standard materials evaluation is limited to destructive and off-line techniques. The present work employed Magnetic Barkhausen Noise (MBN) for nondestructive identification of local residual stress associated with stages in material processing. Analysis of MBN from single strips of NOES demonstrated clear response to applied tensile stress, mechanical shearing, the presence of an insulating coating and punching. The results establish the potential of MBN as a nondestructive testing technology for quality control of electrical steels at various stages of manufacture. (author)

  11. Stressed state of a cement electrical insulation of a pulsed magnet

    International Nuclear Information System (INIS)

    Korenevskij, V.V.; Sugak, E.B.; Fedorenko, L.I.

    1985-01-01

    The stresses arising in cement electrical insulation of a pulsed magnet intended for separation and scanning of beam of secondary particles with 5-10 MeV energy are investigated during its switching. The magnet represents a single-turn construction. During its switching repulsion forces arise in copper buses which affect the core consisting of a set of iron plates. In its turn two cores trying to separate transmit impact load onto cement electrical insulation, the mechanical strength of which determines the construction durability on the whole. For selection of calculation technique the method of photoelasticity is used on models of transparent polymeric materials. Epoxy resin served as material for insulation model, duraluminium for the rest of magnet parts. It is concluded that the calculation technique for the magnet under investigation is a hingeless circular arc

  12. Magnetospheric Multiscale Satellites Observations of Parallel Electric Fields Associated with Magnetic Reconnection

    Science.gov (United States)

    Ergun, R. E.; Goodrich, K. A.; Wilder, F. D.; Holmes, J. C.; Stawarz, J. E.; Eriksson, S.; Sturner, A. P.; Malaspina, D. M.; Usanova, M. E.; Torbert, R. B.; Lindqvist, P.-A.; Khotyaintsev, Y.; Burch, J. L.; Strangeway, R. J.; Russell, C. T.; Pollock, C. J.; Giles, B. L.; Hesse, M.; Chen, L. J.; Lapenta, G.; Goldman, M. V.; Newman, D. L.; Schwartz, S. J.; Eastwood, J. P.; Phan, T. D.; Mozer, F. S.; Drake, J.; Shay, M. A.; Cassak, P. A.; Nakamura, R.; Marklund, G.

    2016-06-01

    We report observations from the Magnetospheric Multiscale satellites of parallel electric fields (E∥ ) associated with magnetic reconnection in the subsolar region of the Earth's magnetopause. E∥ events near the electron diffusion region have amplitudes on the order of 100 mV /m , which are significantly larger than those predicted for an antiparallel reconnection electric field. This Letter addresses specific types of E∥ events, which appear as large-amplitude, near unipolar spikes that are associated with tangled, reconnected magnetic fields. These E∥ events are primarily in or near a current layer near the separatrix and are interpreted to be double layers that may be responsible for secondary reconnection in tangled magnetic fields or flux ropes. These results are telling of the three-dimensional nature of magnetopause reconnection and indicate that magnetopause reconnection may be often patchy and/or drive turbulence along the separatrix that results in flux ropes and/or tangled magnetic fields.

  13. Gastric transit and small intestinal transit time and motility assessed by a magnet tracking system

    Directory of Open Access Journals (Sweden)

    WorsØe Jonas

    2011-12-01

    Full Text Available Abstract Background Tracking an ingested magnet by the Magnet Tracking System MTS-1 (Motilis, Lausanne, Switzerland is an easy and minimally-invasive method to assess gastrointestinal transit. The aim was to test the validity of MTS-1 for assessment of gastric transit time and small intestinal transit time, and to illustrate transit patterns detected by the system. Methods A small magnet was ingested and tracked by an external matrix of 16 magnetic field sensors (4 × 4 giving a position defined by 5 coordinates (position: x, y, z, and angle: θ, ϕ. Eight healthy subjects were each investigated three times: (1 with a small magnet mounted on a capsule endoscope (PillCam; (2 with the magnet alone and the small intestine in the fasting state; and (3 with the magnet alone and the small intestine in the postprandial state. Results Experiment (1 showed good agreement and no systematic differences between MTS-1 and capsule endoscopy when assessing gastric transit (median difference 1 min; range: 0-6 min and small intestinal transit time (median difference 0.5 min; range: 0-52 min. Comparing experiments (1 and (2 there were no systematic differences in gastric transit or small intestinal transit when using the magnet-PillCam unit and the much smaller magnetic pill. In experiments (2 and (3, short bursts of very fast movements lasting less than 5% of the time accounted for more than half the distance covered during the first two hours in the small intestine, irrespective of whether the small intestine was in the fasting or postprandial state. The mean contraction frequency in the small intestine was significantly lower in the fasting state than in the postprandial state (9.90 min-1 vs. 10.53 min-1 (p = 0.03. Conclusion MTS-1 is reliable for determination of gastric transit and small intestinal transit time. It is possible to distinguish between the mean contraction frequency of small intestine in the fasting state and in the postprandial state.

  14. Brief communication "Modeling tornado dynamics and the generation of infrasound, electric and magnetic fields"

    Directory of Open Access Journals (Sweden)

    E. D. Schmitter

    2010-02-01

    Full Text Available Recent observations endorse earlier measurements of time varying electric and magnetic fields generated by tornadoes and dust devils. These signals may provide a means for early warning but together with a proper modeling approach can also provide insight into geometry and dynamics of the vortices. Our model calculations show the existence of pressure resonances characterized as acoustic duct modes with well defined frequencies. These resonances not only generate infrasound but also modulate the charge density and the velocity field and in this way lead to electric and magnetic field oscillations in the 0.5–20-Hz range that can be monitored from a distance of several kilometers.

  15. Spontaneous transfer of magnetically stored energy to Kinetic energy by electric double layers

    International Nuclear Information System (INIS)

    Lindberg, L.; Torven, S.

    1983-05-01

    Current disruptions are investigated in a magnetized plasma column with an inductive external electric circuit. It is found that they persist in spite of the fact that each disruption gives rise to a large inductive over-voltage. This drops off at an electric double layer formed in the plasma where most of the magnetic energy, initially stored in the circuit inductance, is released as particle energy. Simultanously as the current disrupts, the potential level at a local potential minimum in the plasma decreases. This is expected to cause the disruption by reflection of electrons. (authors)

  16. Gap opening and tuning in single-layer graphene with combined electric and magnetic field modulation

    Institute of Scientific and Technical Information of China (English)

    Lin Xin; Wang Hai-Long; Pan Hui; Xu Huai-Zhe

    2011-01-01

    The energy band structure of single-layer graphene under one-dimensional electric and magnetic field modulation is theoretically investigated. The criterion for bandgap opening at the Dirac point is analytically derived with a two-fold degeneracy second-order perturbation method. It is shown that a direct or an indirect bandgap semiconductor could be realized in a single-layer graphene under some specific configurations of the electric and magnetic field arrangement. Due to the bandgap generated in the single-layer graphene, the Klein tunneling observed in pristine graphene is completely suppressed.

  17. Study of electric and magnetic fields on transmission lines using a computer simulation program

    International Nuclear Information System (INIS)

    Robelo Mojica, Nelson

    2011-01-01

    A study was conducted to determine and reduce levels of electric and magnetic fields with different configurations used by the Instituto Costarricense de Electricidad in power transmission lines in Costa Rica. The computer simulation program PLS-CADD with EPRI algorithm has been used to obtain field values close to those actual to lines easements that have worked to date. Different configurations have been compared on equal terms and the lowest levels of electric and magnetic fields are determined. The most appropriate configuration of the tower has been obtained and therefore has decreased exposure to electromagnetic fields people, without affecting the energy demand of the population. (author) [es

  18. Current status of research on power-frequency electric and magnetic fields of research

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    Recent scientific literature has suggested a number of possible human health effects which might be associated with exposure to power frequency electric and magnetic fields. Several authoritative reviews of this subject have been published. currently, the major uncertainty and the major research effort is directed to the issue of these fields and cancer. Therefore, this review will be limited to examining the evidence relating prolonged power-frequency electric and magnetic field exposure to cancer in human populations. This paper reports that the CIGRE expert Group has assessed the research literature in the following areas: epidemiological evidence, animal studies, cellular effects, knowledge of mechanisms

  19. Optical spectroscopy of single Si nanocylinders with magnetic and electric resonances

    DEFF Research Database (Denmark)

    Evlyukhin, A. B.; Eriksen, R. L.; Cheng, W.

    2014-01-01

    . Multipole analysis of the experimental scattering spectra, based on the decomposed discrete dipole approximation, confirms resonant excitation of electric and magnetic dipole modes in the Si nanocylinders. Influences of light polarization and incident angle on the scattering properties of the nanocylinders...... are studied. It is shown that the dependence of resonant excitation of the electric and magnetic modes in the nanocylinders on incident angle and polarization of light allows controlling and manipulating the scattered light in this system. The demonstrated properties of Si nanocylinders can be used...

  20. Ambiguities on electric and magnetic fields for an extended gauge model

    International Nuclear Information System (INIS)

    Colatto, L.P.; Doria, R.M.

    1990-01-01

    Generalized electric and magnetic fields in a system containing N-potential fields in the same U (1) - group are obtained. Bianchi identities, equations of motions, conserved charges and Lorentz forces are developed in association to each of these fields. Such facts confirm that the same parameter α (x) is able to organize the presence of distinct fields. The physics generated from the minimal action principle is independent of the initial definition for the electric (magnetic) field. Nevertheless, such a choice reveals differences in the Bianchi identity context. (author)

  1. Use of small reactors as an alternative to supply electricity to Baja California Sur

    International Nuclear Information System (INIS)

    Alonso, G.; Portes, E.; Ramirez, J. R.; Ortega, G.

    2016-09-01

    The state of Baja California Sur (Mexico) does not form part of the national interconnected electrical system of the country, reason why is local its electrical power supply; one of the alternatives to cover future demands is the use of gas-based combined cycles, which presents the additional problem of including a high price for gas transportation in its costs. In order to reduce total costs, including investment, fuels and operation and maintenance in the operation of the Baja California Sur state electricity system in the coming years, mainly due to the estimated natural gas cost order of $11.50 dollars per million BTU, a proposal is presented to reduce the costs of the electrical system by replacing the necessary combined cycles with the new Small Modular Reactor type nuclear reactors, this alternative is economically competitive. (Author)

  2. Magnetic properties and recrystallization texture of phosphorus-added non-oriented electrical steel sheets

    International Nuclear Information System (INIS)

    Tanaka, I.; Yashiki, H.

    2006-01-01

    The effect of phosphorus on magnetic properties and recrystallization texture has been investigated in non-oriented electrical steel sheets to develop low core loss and high permeability core materials. Specimens with different phosphorus contents were cold-rolled to various thicknesses, i.e. with various cold-rolling reductions, and annealed for recrystallization and grain growth. Although magnetic induction of the steel with low phosphorus content dramatically dropped with reducing thickness, i.e. with increasing in cold-rolling reduction, that of the steel with high phosphorus content only slightly decreased. The most effective way to reduce core loss was to reduce thickness of electrical steel sheets. Therefore, phosphorus-added thin gauge non-oriented electrical steel sheets have achieved low core loss and high permeability. The typical magnetic properties of phosphorus-added non-oriented electrical steel sheets 0.27mm in sheet thickness were 16.6W/kg in W 10/400 and 1.73T in B 50 . These excellent magnetic properties were due to the recrystallization texture control. {111} component in recrystallization texture was suppressed by the phosphorus segregation at initial grain boundaries. Accordingly, phosphorus would greatly contribute to the improvement of magnetic properties

  3. Permanent Magnet Brushless DC Motor and Mechanical Structure Design for the Electric Impact Wrench System

    Directory of Open Access Journals (Sweden)

    Chengyuan He

    2018-05-01

    Full Text Available This paper presents an analytical method to design an interior permanent magnet brushless DC electric motor (IPMBLDC motor for a kind of electric impact wrench used for loading and unloading car bolts. It takes into account magnet assembly gap, rotor saturation webs, and bridges. Assumed flux leakage coefficient and selected working point of a permanent magnet were used in the initial design. An advanced equivalent magnetic circuit was developed to verify the total flux leakage and the quiescent operating point based on initial design parameters. Key design method points are considered and analyzed. Thermal analysis is given to simulate the temperature rise of all parts of the motor. The new impact wrench mechanical structure is designed, and its working principle analyzed. An electromagnetic field analysis based on MATLAB and the MAXWELL 2D finite element method (FEM were used in the design to verify the equivalent magnetic circuit and optimize the IPMBLDC motor parameters. Experimental results are obtained to verify the design. The electrical and mechanical designs are combined and an analytical IPMBLDC motor design method is provided. We also show an innovative and reasonable mechanical dynamical calculation method for the impact wrench system, which can be used in whole system design of other functional electric tools.

  4. Electrically tunable magnetic configuration on vacancy-doped GaSe monolayer

    Science.gov (United States)

    Tang, Weiqing; Ke, Congming; Fu, Mingming; Wu, Yaping; Zhang, Chunmiao; Lin, Wei; Lu, Shiqiang; Wu, Zhiming; Yang, Weihuang; Kang, Junyong

    2018-03-01

    Group-IIIA metal-monochalcogenides with the enticing properties have attracted tremendous attention across various scientific disciplines. With the aim to satisfy the multiple demands of device applications, here we report a design framework on GaSe monolayer in an effort to tune the electronic and magnetic properties through a dual modulation of vacancy doping and electric field. A half-metallicity with a 100% spin polarization is generated in a Ga vacancy doped GaSe monolayer due to the nonbonding 4p electronic orbital of the surrounding Se atoms. The stability of magnetic moment is found to be determined by the direction of applied electric field. A switchable magnetic configuration in Ga vacancy doped GaSe monolayer is achieved under a critical electric field of 0.6 V/Å. Electric field induces redistribution of the electronic states. Finally, charge transfers are found to be responsible for the controllable magnetic structure in this system. The magnetic modulation on GaSe monolayer in this work offers some references for the design and fabrication of tunable two-dimensional spintronic device.

  5. Electric and magnetic field reduction and research: A report to the Washington State Legislature

    International Nuclear Information System (INIS)

    Geissinger, L.G.; Waller, P.; Chartier, V.L.; Olsen, R.G.

    1993-01-01

    Increasingly, citizens of Washington State are expressing their concerns about possible adverse health effects of electric and magnetic fields (EMF) from electric utility power systems. A number of legislative proposals over the past several years have prompted governmental officials to evaluate available options for reducing electric and magnetic field strengths surrounding these systems (with a concentration on magnetic fields) or otherwise manage public exposure to power lines by increasing land use controls and setbacks for new development. Unsuccessful proposals brought before the Washington Legislature include 2 mG magnetic field limits for new transmission lines at the right-of-way edge; a temporary moratorium on transmission construction; requirements for providing public information on EMF; and expansion of the role of state governmental agencies in transmission siting and design. A successful Whatcom County initiative limits the voltage of new transmission to 115 kV in all but industrial land use zones, an action likely to have an unintended outcome of increasing magnetic fields in some areas. It is clear that better communication is needed about possible options for EMF management, costs and consequences, despite the fact scientific evidence on the existence of human health effects is inconclusive. This paper describes the work that Washington State undertook in 1990-92 in response to Engrossed Substitute Senate Bill 6771 establishing the Electric Transmission Research Needs Task Force. The Task Force was directed to report to the Legislature on possible exposure reduction methods; recommending engineering research that could lead to more effective approaches in the future

  6. Lorentz invariance from classical particle paths in quantum field theory of electric and magnetic charge

    International Nuclear Information System (INIS)

    Brandt, R.A.; Neri, F.; Zwanziger, D.

    1979-01-01

    We establish the Lorentz invariance of the quantum field theory of electric and magnetic charge. This is a priori implausible because the theory is the second-quantized version of a classical field theory which is inconsistent if the minimally coupled charged fields are smooth functions. For our proof we express the generating functional for the gauge-invariant Green's functions of quantum electrodynamics: with or without magnetic charge: as a path integral over the trajectories of classical charged point particles. The electric-electric and electric-magnetic interactions contribute factors exp(JDJ) and exp(JD'K), where J and K are the electric and magnetic currents of classical point particles and D is the usual photon propagator. The propagator D' involves the Dirac string but exp(JD'K) depends on it only through a topological integer linking string and classical particle trajectories. The charge quantization condition e/sub i/g/sub j/ - g/sub i/e/sub j/ = integer then suffices to make the gauge-invariant Green's functions string independent. By implication our formulation shows that if the Green's functions of quantum electrodynamics are expressed as usual as functional integrals over classical charged fields, the smooth field configurations have measure zero and all the support of the Feynman measure lies on the trajectories of classical point particles

  7. Non-contact magnetic coupled power and data transferring system for an electric vehicle

    International Nuclear Information System (INIS)

    Matsuda, Y.; Sakamoto, H.

    2007-01-01

    We have developed a system which transmits electric power and communication data simultaneously in a non-contact method using a magnetic coupling coil. Already, we are developing the fundamental technology of a non-contact charging system, and this is applied in electric shavers, electric toothbrushes, etc. Moreover, basic experiments are being conducted for applying this non-contact charging system to electric equipments such as an electric vehicle (EV), which is a zero emission vehicle and environmentally excellent and will be the transportation means of the next generation. The technology can also be applied in other electronic equipment, etc. However, since the power supply route for these individual devices is independent, the supply system is complicated. EV also has to perform the transmission of electric power and the transmission of information (data), such as the amount of the charge, in a separate system, and thus is quite complicated. In this study, by performing simultaneously the transmission of electric power and information (data) using magnetic coupling technology in which it does not contact, the basic experiment aimed at attaining and making unification of a system simple was conducted, and the following good results were obtained: (1) Electric power required for load can be transmitted easily by non-contact. (2) A signal can easily be transmitted bidirectionally by non-contact. (3) This system is reliable, and is widely applicable

  8. Electrical conductivity of a fully ionized plasma in a magnetic field

    International Nuclear Information System (INIS)

    Vaucher, B.; Vaclavik, J.; Schneider, H.

    1975-01-01

    In this experimental work the authors have investigated the electrical conductivity of a homogeneous fully ionized plasma in a homogeneous magnetic field. In particular, the conductivity perpendicular to the magnetic field was studied by means of the magnetoacoustic resonance for different values of the parameter ωsub(c)/γsub(ei) where ωsub(c) is the electron cyclotron frequency and γsub(ei) is the collision frequency between electrons and ions. (Auth.)

  9. All-electric-controlled spin current switching in single-molecule magnet-tunnel junctions

    Science.gov (United States)

    Zhang, Zheng-Zhong; Shen, Rui; Sheng, Li; Wang, Rui-Qiang; Wang, Bai-Gen; Xing, Ding-Yu

    2011-04-01

    A single-molecule magnet (SMM) coupled to two normal metallic electrodes can both switch spin-up and spin-down electronic currents within two different windows of SMM gate voltage. Such spin current switching in the SMM tunnel junction arises from spin-selected single electron resonant tunneling via the lowest unoccupied molecular orbit of the SMM. Since it is not magnetically controlled but all-electrically controlled, the proposed spin current switching effect may have potential applications in future spintronics.

  10. Direct conversion of fusion energy into the electric one in the 'Dragon' magnetic confinement system

    International Nuclear Information System (INIS)

    Glagolev, V.M.; Timofeev, A.V.

    1993-01-01

    It is shown that recuperator in which the thermal energy of particles is transformed into electric oue under drift in crossed fields is naturally coupled with dragontype magnetic confinement system, so the recuperation process can be initiated in the dragon magnetic field. A number of questions occuring under analysis of recuperator-dragon system is considered, including the dynamics of particle transfer to the recuperator, the share of particles entering the recuperator, the effect of rotational transform and the recuperation efficiency

  11. Cable testing for Fermilab's high field magnets using small racetrack coils

    International Nuclear Information System (INIS)

    Feher, S.; Ambrosio, G.; Andreev, N.; Barzi, E.; Bordini, B.; Bossert, R.; Carcagno, R.; Kashikhin, V.I.; Kashikhin, V.V.; Lamm, M.J.; Novitski, I.; Orris, D.; Pischalnikov, Y.; Sylvester, C.; Tartaglia, M.; Yamada, R.; Zlobin, A.V.

    2004-01-01

    As part of the High Field Magnet program at Fermilab simple magnets have been designed utilizing small racetrack coils based on a sound mechanical structure and bladder technique developed by LBNL. Two of these magnets have been built in order to test Nb 3 Sn cables used in cos-theta dipole models. The powder-in-tube strand based cable exhibited excellent performance. It reached its critical current limit within 14 quenches. Modified jelly roll strand based cable performance was limited by magnetic instabilities at low fields as previously tested dipole models which used similar cable

  12. Magnetic and electrical properties of zincblende CrAs

    International Nuclear Information System (INIS)

    Chen Peng; Takamura, K

    2008-01-01

    This paper reports that 9 nm zincblende CrAs is grown by molecular-beam epitaxy on InAs buffer layer. The zb-CrAs shows ferromagnetism at room temperature and the total magnetic moment 3.09 ± 0.15 μ B per CrAs unit. The temperature dependence of zb-CrAs resistance R shows metallic behaviour

  13. Optimal designs of small CHP plants in a market with fluctuating electricity prices

    International Nuclear Information System (INIS)

    Lund, H.; Andersen, A.N.

    2005-01-01

    Combined Heat and Power production (CHP) are essential for implementation of the climate change response objectives in many countries. In an introduction period, small CHP plants have typically been offered fixed electricity prices, but in many countries, such pricing conditions are now being replaced by spot market prices. Consequently, new methodologies and tools for the optimisation of small CHP plant designs are needed. The small CHP plants in Denmark are already experienced in optimising their electricity production against the triple tariff, which has existed for almost 10 years. Consequently, the CHP plants have long term experience in organising when to switch on and off the CHP units in order to optimise their profit. Also, the CHP owners have long term experience in designing their plants. For instance, small CHP plants in Denmark have usually invested in excess capacity on the CHP units in combination with heat storage capacity. Thereby, the plants have increased their performance in order to optimise revenues. This paper presents the Danish experience with methodologies and software tools, which have been used to design investment and operation strategies for almost all small CHP plants in Denmark during the decade of the triple tariff. Moreover, the changes in such methodologies and tools in order to optimise performance in a market with fluctuating electricity prices are presented and discussed

  14. Magnetic Cellulose Nanocrystal Based Anisotropic Polylactic Acid Nanocomposite Films: Influence on Electrical, Magnetic, Thermal, and Mechanical Properties.

    Science.gov (United States)

    Dhar, Prodyut; Kumar, Amit; Katiyar, Vimal

    2016-07-20

    This paper reports a single-step co-precipitation method for the fabrication of magnetic cellulose nanocrystals (MGCNCs) with high iron oxide nanoparticle content (∼51 wt % loading) adsorbed onto cellulose nanocrystals (CNCs). X-ray diffraction (XRD), Fourier transform infrared (FTIR), and Raman spectroscopic studies confirmed that the hydroxyl groups on the surface of CNCs (derived from the bamboo pulp) acted as anchor points for the adsorption of Fe3O4 nanoparticles. The fabricated MGCNCs have a high magnetic moment, which is utilized to orient the magnetoresponsive nanofillers in parallel or perpendicular orientations inside the polylactic acid (PLA) matrix. Magnetic-field-assisted directional alignment of MGCNCs led to the incorporation of anisotropic mechanical, thermal, and electrical properties in the fabricated PLA-MGCNC nanocomposites. Thermomechanical studies showed significant improvement in the elastic modulus and glass-transition temperature for the magnetically oriented samples. Differential scanning calorimetry (DSC) and XRD studies confirmed that the alignment of MGCNCs led to the improvement in the percentage crystallinity and, with the absence of the cold-crystallization phenomenon, finds a potential application in polymer processing in the presence of magnetic field. The tensile strength and percentage elongation for the parallel-oriented samples improved by ∼70 and 240%, respectively, and for perpendicular-oriented samples, by ∼58 and 172%, respectively, in comparison to the unoriented samples. Furthermore, its anisotropically induced electrical and magnetic properties are desirable for fabricating self-biased electronics products. We also demonstrate that the fabricated anisotropic PLA-MGCNC nanocomposites could be laminated into films with the incorporation of directionally tunable mechanical properties. Therefore, the current study provides a novel noninvasive approach of orienting nontoxic bioderived CNCs in the presence of low

  15. MODELING THE SUN’S SMALL-SCALE GLOBAL PHOTOSPHERIC MAGNETIC FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, K. A. [Division of Computing and Mathematics, Abertay University, Kydd Building, Dundee, Bell Street, DD1 1HG, Scotland (United Kingdom); Mackay, D. H., E-mail: k.meyer@abertay.ac.uk [School of Mathematics and Statistics, University of St Andrews, North Haugh, St Andrews, KY16 9SS, Scotland (United Kingdom)

    2016-10-20

    We present a new model for the Sun’s global photospheric magnetic field during a deep minimum of activity, in which no active regions emerge. The emergence and subsequent evolution of small-scale magnetic features across the full solar surface is simulated, subject to the influence of a global supergranular flow pattern. Visually, the resulting simulated magnetograms reproduce the typical structure and scale observed in quiet Sun magnetograms. Quantitatively, the simulation quickly reaches a steady state, resulting in a mean field and flux distribution that are in good agreement with those determined from observations. A potential coronal magnetic field is extrapolated from the simulated full Sun magnetograms to consider the implications of such a quiet photospheric magnetic field on the corona and inner heliosphere. The bulk of the coronal magnetic field closes very low down, in short connections between small-scale features in the simulated magnetic network. Just 0.1% of the photospheric magnetic flux is found to be open at 2.5 R {sub ⊙}, around 10–100 times less than that determined for typical Helioseismic and Magnetic Imager synoptic map observations. If such conditions were to exist on the Sun, this would lead to a significantly weaker interplanetary magnetic field than is currently observed, and hence a much higher cosmic ray flux at Earth.

  16. Structural, magnetic, and electrical properties of Gd-doped BiFeO3 nanoparticles with reduced particle size

    International Nuclear Information System (INIS)

    Lotey, Gurmeet Singh; Verma, N. K.

    2012-01-01

    Pure and Gd-doped BiFeO 3 nanoparticles have been synthesized by sol–gel method. The significant effects of size and Gd-doping on structural, electrical, and magnetic properties have been investigated. X-ray diffraction study reveals that the pure BiFeO 3 nanoparticles possess rhombohedral structure, but with 10% Gd-doping complete structural transformation from rhombohedral to orthorhombic has been observed. The particle size of pure and Gd-doped BiFeO 3 nanoparticles, calculated using Transmission electron microscopy, has been found to be in the range 25–15 nm. Pure and Gd-doped BiFeO 3 nanoparticles show ferromagnetic character, and the magnetization increases with decrease in particle size and increase in doping concentration. Scanning electron microscopy study reveals that grain size decreases with increase in Gd concentration. Well-saturated polarization versus electric field loop is observed for the doped samples. Leakage current density decreases by four orders by doping Gd in BiFeO 3 . The incorporation of Gd in BiFeO 3 enhances spin as well as electric polarization at room temperature. The possible origin of enhancement in these properties has been explained on the basis of dopant and its concentration, phase purity, small particle, and grain size.

  17. Considerations of coil protection and electrical connection schemes in large superconducting toroidal magnet system

    International Nuclear Information System (INIS)

    Yeh, H.T.

    1976-03-01

    A preliminary comparison of several different coil protection and electrical connection schemes for large superconducting toroidal magnet systems (STMS) is carried out. The tentative recommendation is to rely on external dump resistors for coil protection and to connect the coils in the toroidal magnet in several parallel loops (e.g., every fourth coil is connected into a single series loop). For the fault condition when a single coil quenches, the quenched coil should be isolated from its loop by switching devices. The magnet, as a whole, should probably be discharged if more than a few coils have quenched

  18. Quantum dynamics of an electric charge in an oscillating pulsed magnetic field

    International Nuclear Information System (INIS)

    Oliveira, I.S.; Guimaraes, A.P.; Silva, X.A. da

    1996-11-01

    The motion of a charged particle under the action of a time-dependent oscillating magnetic field has been investigated. For one and two magnetic pulses were obtained analytical expressions for the free current decay and current echo in agreement with a recently proposed classical description of electrical current in fields E and B. When the resonance condition is achieved, the axis of quantization is turned over by 90 degrees. The results suggest a magnetic pulsed resonant method to separate charged particles in a beam. (author). 12 refs

  19. Photoabsorption spectra in the perturbative regime for atoms in crossed electric and magnetic fields

    International Nuclear Information System (INIS)

    Marxer, H.; Moser, I.; O'Mahony, P.F.; Mota-Furtado, F.

    1994-01-01

    We calculate photoabsorption spectra of atoms in crossed electric and magnetic fields using a truncated basis of Coulomb eigenfunctions. The method yields spectra in the regime where inter-n-mixing is not dominant and allows for the treatment of non-hydrogenic atoms via a simple recourse to quantum defects. We compare results for hydrogen to those obtained in second order perturbation theory where the residual degeneracy left in first order perturbation theory is completely lifted and we show that only a very small basis size is needed to achieve convergence to within the accuracy of second order perturbation theory. In the case of lithium the coupling of an incomplete hydrogen-like manifold to states with non-negligible quantum defects substantially modifies the spectra obtained in comparison to the purely hydrogenic spectra. In the inter-n-mixing regime we also compare our convoluted results directly with an experimental spectrum for hydrogen and find good agreement below the saddle point. (Author)

  20. EMMA - the electric and magnetic monitor of the aurora on Astrid-2

    DEFF Research Database (Denmark)

    Blomberg, L.G.; Marklund, G.T.; Lindqvist, P.A.

    2004-01-01

    discuss in the present paper, is designed to provide simultaneous sampling of two electric and three magnetic field components up to about 1 kHz. The spin plane components of the electric field are measured by two pairs of opposing probes extended by wire booms with a separation distance of 6.7 m....... The probes have titanium nitride (TiN) surfaces. which has proved to be a material with excellent properties for providing good electrical contact between probe and plasma. The wire booms are of a new design in which the booms in the stowed position are wound around the exterior of the spacecraft body...

  1. Electric field-controlled magnetization in exchange biased IrMn/Co/PZT multilayers

    International Nuclear Information System (INIS)

    Huong Giang, D T; Duc, N H; Agnus, G; Maroutian, T; Lecoeur, P

    2013-01-01

    Electric-field modulating exchange bias and near 180° deterministic magnetization switching at room temperature are demonstrated in simple antiferromagnetic/ferromagnetic/ferroelectric (AFM/FM/FE) exchange-coupled multiferroic multilayers of IrMn/Co/PZT. A rather large exchange bias field shift up to ΔH ex /H ex = 500% was obtained. This change governs mainly the electric-field strength rather than the applied current. It is explained as being realized through the competition between the electric-field induced uniaxial and unidirectional anisotropies. These results show good prospects for low-power spintronic devices. (paper)

  2. On-Chip Magnetic Platform for Single-Particle Manipulation with Integrated Electrical Feedback.

    Science.gov (United States)

    Monticelli, Marco; Torti, Andrea; Cantoni, Matteo; Petti, Daniela; Albisetti, Edoardo; Manzin, Alessandra; Guerriero, Erica; Sordan, Roman; Gervasoni, Giacomo; Carminati, Marco; Ferrari, Giorgio; Sampietro, Marco; Bertacco, Riccardo

    2016-02-17

    Methods for the manipulation of single magnetic particles have become very interesting, in particular for in vitro biological studies. Most of these studies require an external microscope to provide the operator with feedback for controlling the particle motion, thus preventing the use of magnetic particles in high-throughput experiments. In this paper, a simple and compact system with integrated electrical feedback is presented, implementing in the very same device both the manipulation and detection of the transit of single particles. The proposed platform is based on zig-zag shaped magnetic nanostructures, where transverse magnetic domain walls are pinned at the corners and attract magnetic particles in suspension. By applying suitable external magnetic fields, the domain walls move to the nearest corner, thus causing the step by step displacement of the particles along the nanostructure. The very same structure is also employed for detecting the bead transit. Indeed, the presence of the magnetic particle in suspension over the domain wall affects the depinning field required for its displacement. This characteristic field can be monitored through anisotropic magnetoresistance measurements, thus implementing an integrated electrical feedback of the bead transit. In particular, the individual manipulation and detection of single 1-μm sized beads is demonstrated. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. The role of magnetic-field-aligned electric fields in auroral acceleration

    International Nuclear Information System (INIS)

    Block, L.P.; Faelthammar, C.G.

    1990-01-01

    Electric field measurements on the Swedish satellite Viking have confirmed and extended earlier observations on S3-3 and provided further evidence of the role of dc electric fields in auroral acceleration processes. On auroral magnetic field lines the electric field is strongly fluctuating both transverse and parallel to the magnetic field. The significance of these fluctuations for the auroral acceleration process is discussed. A definition of dc electric fields is given in terms of their effects on charged particles. Fluctuations below several hertz are experienced as dc by typical auroral electrons if the acceleration length is a few thousand kilometers. For ions the same is true below about 0.1 Hz. The magnetic-field-aligned (as well as the transverse) component of the electric field fluctuations has a maximum below 1 Hz, in a frequency range that appears as dc to the electrons but not to the ions. This allows it to cause a selective acceleration, which may be important in explaining some of the observed characteristics of auroral particle distributions. The electric field observations on Viking support the conclusion that magnetic-field-aligned potential drops play an important role in auroral acceleration, in good agreement with particle observations boht on Viking and on the DE satellites. They also show that a large part, or even all, of the accelerating potential drop may be accounted for by numerous weak (about a volt) electric double layers, in agreement with earlier observations on the S3-3 satellite and with an early theoretical suggestion by L. Block

  4. Magnetic structures, phase diagram and spin waves of magneto-electric LiNiPO4

    DEFF Research Database (Denmark)

    Jensen, Thomas Bagger Stibius

    2007-01-01

    LiNiPO4 is a magneto-electric material, having co-existing antiferromagnetic and ferroelectric phases when suitable magnetic fields are applied at low temperatures. Such systems have received growing interest in recent years, but the nature of the magneticelectric couplings is yet to be fully...... through the last three years, it is not the primary subject of this thesis. The objective of the phD project has been to provide groundwork that may be beneficiary to future studies of LiNiPO4. More specifically, we have mapped out the magnetic HT phase diagram with magnetic fields below 14.7 T applied...... along the crystallographic c-axis, determined the magnetic structures for the phases in the phase diagram, and have set up a spin model Hamiltonian describing the spin wave dynamics and estimating the relevant magnetic interactions....

  5. Electrical performance of a string of magnets representing a half-cell of the LHC machine

    International Nuclear Information System (INIS)

    Rodriguez-Mateos, F.; Coull, L.; Dahlerup-Petersen, K.; Hagedorn, D.; Krainz, G.; Rijllart, A.; McInturff, A.

    1996-01-01

    Tests have been carried out on a string of prototype superconducting magnets, consisting of one double-quadrupole and two double-dipoles forming the major part of a half-cell of the LHC machine. The magnets are protected individually by cold diodes and quench heaters. The electrical aspects of these tests are described here. The performance during quench of the protection diodes and the associated interconnections was studied. Tests determined the magnet quench performance in training and at different ramp-rates, and investigated the inter-magnet propagation of quenches. Current lead and inter-magnet contact resistances were controlled and the performance of the power converter and the dump switches assessed

  6. DFBX boxes -- electrical and cryogenic distribution boxes for the superconducting magnets in the LHC straight sections

    International Nuclear Information System (INIS)

    Zbasnik, Jon P.; Corradi, Carol A.; Gourlay, S.A.; Green, MichaelA.; Hafalia, Aurelio Q.; Kajiyama, Yoichi Jr.; Knolls, Michael J.; LaMantia, Roberto F.; Rasson, Joseph E.; Reavill, Dulie; Turner, William C.

    2002-01-01

    DFBX distribution boxes provide cryogenic and electrical services to superconducting quadrupoles and to a superconducting dipole at either end of four of the long straight sections in the LHC. The DFBX boxes also provide instrumentation and quench protection to the magnets. Current for the quadrupole and the dipole magnet is delivered through leads that combine HTS and gas cooled leads. Current for the 600 A and 120 A correction magnets is provided by pure gas-cooled leads. The bus bars from the leads to the magnets pass through low leak-rate lambda plugs between 1.8 K and 4.4 K. The heat leak into the 1.9 K region from the liquid helium tank is determined by the design of the lambda plugs. This paper describes the DFBX boxes and their function of delivering current and instrumentation signals to the magnets

  7. Electrical performance of a string of magnets representing a half-cell of the LHC machine

    International Nuclear Information System (INIS)

    Rodriguez-Mateos, F.; Coull, L.; Dahlerup-Petersen, K.; Hagedorn, D.; Krainz, G.; Rijllart, A.; McInturff, A.

    1995-01-01

    Tests have been carried out on a string prototype superconducting magnets, consisting of one double-quadrupole and two double-dipoles forming the major part of a half-cell of the LHC machine. The magnets are protected individually by ''cold diodes'' and quench heaters. The electrical aspects of these tests are described here. The performance during quench of the protection diodes and the associated interconnections was studied. Tests determined the magnet quench performance in training and at different ramp-rates, and investigated the inter-magnet propagation of quenches. Current lead and inter-magnet contact resistances were controlled and the performance of the power converter and the dump switches assessed

  8. Small-scale gradients of charged particles in the heliospheric magnetic field

    International Nuclear Information System (INIS)

    Guo, Fan; Giacalone, Joe

    2014-01-01

    Using numerical simulations of charged-particles propagating in the heliospheric magnetic field, we study small-scale gradients, or 'dropouts,' in the intensity of solar energetic particles seen at 1 AU. We use two turbulence models, the foot-point random motion model and the two-component model, to generate fluctuating magnetic fields similar to spacecraft observations at 1 AU. The turbulence models include a Kolmogorov-like magnetic field power spectrum containing a broad range of spatial scales from those that lead to large-scale field-line random walk to small scales leading to resonant pitch-angle scattering of energetic particles. We release energetic protons (20 keV-10 MeV) from a spatially compact and instantaneous source. The trajectories of energetic charged particles in turbulent magnetic fields are numerically integrated. Spacecraft observations are mimicked by collecting particles in small windows when they pass the windows at a distance of 1 AU. We show that small-scale gradients in the intensity of energetic particles and velocity dispersions observed by spacecraft can be reproduced using the foot-point random motion model. However, no dropouts are seen in simulations using the two-component magnetic turbulence model. We also show that particle scattering in the solar wind magnetic field needs to be infrequent for intensity dropouts to form.

  9. Electric field controlled reversible magnetic anisotropy switching studied by spin rectification

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Hengan; Fan, Xiaolong, E-mail: fanxiaolong@lzu.edu.cn; Wang, Fenglong; Jiang, Changjun; Rao, Jinwei; Zhao, Xiaobing; Xue, Desheng [Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Gui, Y. S.; Hu, C.-M. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada)

    2014-03-10

    In this letter, spin rectification was used to study the electric field controlled dynamic magnetic properties of the multiferroic composite which is a Co stripe with induced in-plane anisotropy deposited onto a Pb(Mg{sub 1∕3}Nb{sub 2∕3})O{sub 3}-PbTiO{sub 3} substrate. Due to the coupling between piezoelectric and magnetoelastic effects, a reversible in-plane anisotropy switching has been realized by varying the history of the applied electric field. This merit results from the electric hysteresis of the polarization in the nonlinear piezoelectric regime, which has been proved by a butterfly type electric field dependence of the in-plane anisotropy field. Moreover, the electric field dependent effective demagnetization field and linewidth have been observed at the same time.

  10. Electric field controlled reversible magnetic anisotropy switching studied by spin rectification

    International Nuclear Information System (INIS)

    Zhou, Hengan; Fan, Xiaolong; Wang, Fenglong; Jiang, Changjun; Rao, Jinwei; Zhao, Xiaobing; Xue, Desheng; Gui, Y. S.; Hu, C.-M.

    2014-01-01

    In this letter, spin rectification was used to study the electric field controlled dynamic magnetic properties of the multiferroic composite which is a Co stripe with induced in-plane anisotropy deposited onto a Pb(Mg 1∕3 Nb 2∕3 )O 3 -PbTiO 3 substrate. Due to the coupling between piezoelectric and magnetoelastic effects, a reversible in-plane anisotropy switching has been realized by varying the history of the applied electric field. This merit results from the electric hysteresis of the polarization in the nonlinear piezoelectric regime, which has been proved by a butterfly type electric field dependence of the in-plane anisotropy field. Moreover, the electric field dependent effective demagnetization field and linewidth have been observed at the same time

  11. Large non-volatile tuning of magnetism mediated by electric field in Fe–Al/Pb(Mg1/3Nb2/3)O3–PbTiO3 heterostructure

    International Nuclear Information System (INIS)

    Chen, Zhendong; Gao, Cunxu; Wei, Yanping; Zhang, Peng; Wang, Yutian; Zhang, Chao; Ma, Zhikun

    2017-01-01

    Electric-field control of magnetism is now an attractive trend to approach a new kind of fast, low-power-cost memory device. In this work, we report a strong non-volatile electric control of magnetism in an Fe–Al/Pb(Mg 1/3 Nb 2/3 )O 3 –PbTiO 3 heterostructure. In this system, a 90° rotation of the in-plane uniaxial magnetic anisotropy is exhibited during the increase of the external electric field, which means the easy axis turns into a hard axis and the hard axis turns into an easy one. Additionally, a non-volatile switch of the remanence is observed after a sweeping of the electric field from 0 kV cm −1 to  ±  10 kV cm −1 , then back to 0 kV cm −1 . More interestingly, a 20% non-volatile magnetic state tuning driven by individual pulse electric fields is shown in contrast to large tuning up to 120% caused by pulse electric fields with small assistant pulse magnetic fields, which means a 180° reverse of the magnetization. These remarkable behaviors demonstrated in this heterostructure reveal a promising potential application in magnetic memory devices mediated by electric fields. (paper)

  12. Very-low-frequency and low-frequency electric and magnetic fields associated with electric shuttle bus wireless charging

    International Nuclear Information System (INIS)

    Tell, R. A.; Kavet, R.; Bailey, J. R.; Halliwell, J.

    2014-01-01

    Tests conducted to date at the University of Tennessee at Chattanooga (UTC) indicate that wireless charging of the Chattanooga Area Regional Transportation Authority's (CARTA) downtown shuttle bus, currently operating with off-board battery charging technology, offers significant improvements in performance and cost. The system operates at a frequency of 20 kHz and a peak power of 60 kW. Because the system's wireless charging is expected to occur during a nominal 3-min charging period with passengers on-board, the magnetic and electric fields associated with charging were characterised at UTC's Advanced Vehicle Test Facility and compared with established human exposure limits. The two most prominent exposure limits are those published by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the Institute for Electrical and Electronic Engineers (IEEE). Both organisations include limits for groups who are trained (workers in specific industries) to be aware of electromagnetic environments and their potential hazards, as well as a lower set of limits for the general public, who are assumed to lack such awareness. None of the magnetic or electric fields measured either within or outside the bus during charging exceeded either the ICNIRP or the IEEE exposure limits for the general public. (authors)

  13. Magnetic and electrical transport properties of delta-doped amorphous Ge:Mn magnetic semiconductors

    International Nuclear Information System (INIS)

    Li, H.L.; Lin, H.T.; Wu, Y.H.; Liu, T.; Zhao, Z.L.; Han, G.C.; Chong, T.C.

    2006-01-01

    We report on the growth and characterization of delta-doped amorphous Ge:Mn diluted magnetic semiconductor thin films on GaAs (0 0 1) substrates. The fabricated samples exhibit different magnetic behaviors, depending on the Mn doping concentration. The Curie temperature was found to be dependent on both the Mn doping concentration and spacing between the doping layers. A sharp drop in magnetization and rise in resistivity are observed at low temperature in samples with high Mn doping concentrations, which is also accompanied by a negative thermal remanent magnetization (TRM) in the higher temperature range. The temperature at which the magnetization starts to drop and the negative TRM appears show a correlation with the Mn doping concentration. The experimental results are discussed based on the formation of ferromagnetic regions at high temperature and antiferromagnetic coupling between these regions at low temperature

  14. Magnetic and electric deflector spectrometers for ion emission analysis from laser generated plasma

    Directory of Open Access Journals (Sweden)

    Torrisi Lorenzo

    2018-01-01

    Full Text Available The pulsed laser-generated plasma in vacuum and at low and high intensities can be characterized using different physical diagnostics. The charge particles emission can be characterized using magnetic, electric and magnet-electrical spectrometers. Such on-line techniques are often based on time-of-flight (TOF measurements. A 90° electric deflection system is employed as ion energy analyzer (IEA acting as a filter of the mass-to-charge ratio of emitted ions towards a secondary electron multiplier. It determines the ion energy and charge state distributions. The measure of the ion and electron currents as a function of the mass-to-charge ratio can be also determined by a magnetic deflector spectrometer, using a magnetic field of the order of 0.35 T, orthogonal to the ion incident direction, and an array of little ion collectors (IC at different angles. A Thomson parabola spectrometer, employing gaf-chromix as detector, permits to be employed for ion mass, energy and charge state recognition. Mass quadrupole spectrometry, based on radiofrequency electric field oscillations, can be employed to characterize the plasma ion emission. Measurements performed on plasma produced by different lasers, irradiation conditions and targets are presented and discussed. Complementary measurements, based on mass and optical spectroscopy, semiconductor detectors, fast CCD camera and Langmuir probes are also employed for the full plasma characterization. Simulation programs, such as SRIM, SREM, and COMSOL are employed for the charge particle recognition.

  15. Availability of the electric drive systems containing flux switching permanent magnet machines

    NARCIS (Netherlands)

    Wang, L.; Sfakianakis, G.; Paulides, J.J.H.; Lomonova, E.A.

    2016-01-01

    This paper investigates how to improve availability of an electrical drive containing a 3-phase 12/10 (12 stator tooth/10 rotor poles) flux switching permanent magnet machine. In this respect, Field-Oriented Control and Space-Vector Pulse-Width-Modulation strategies will be applied with 3-phase

  16. Dependent of electrical resistivity of thin wire on magnetic field and temperature

    International Nuclear Information System (INIS)

    Sadeghi, E.; Zare, M.

    2006-01-01

    Variation of electrical resistivity of Bismuth nano wire versus magnetic field the and temperature are considered. We study the size effect and surface scattering of the carrier in thin wire for systems with ellipsoidal Fermi surfaces. Results are in good agreement with experimental points

  17. Magnetic susceptibility and electrical conductivity of metallic dental materials and their impact on MR imaging artifacts

    Czech Academy of Sciences Publication Activity Database

    Starčuková, Jana; Starčuk jr., Zenon; Hubálková, H.; Linetskiy, I.

    2008-01-01

    Roč. 24, č. 6 (2008), s. 715-723 ISSN 0109-5641 R&D Projects: GA MZd NR8110 Institutional research plan: CEZ:AV0Z20650511 Keywords : metallic dental materials * dental alloys * amalgams * MR imaging * magnetic susceptibility * electric conductivity * image artifact Subject RIV: FF - HEENT, Dentistry Impact factor: 2.941, year: 2008

  18. Electrical resistivity, Hall coefficient and electronic mobility in indium antimonide at different magnetic fields and temperatures

    International Nuclear Information System (INIS)

    Jee, Madan; Prasad, Vijay; Singh, Amita

    1995-01-01

    The electrical resistivity, Hall coefficient and electronic mobility of n-type and p-type crystals of indium antimonide have been measured from 25 degC-100 degC temperature range. It has been found by this measurement that indium antimonide is a compound semiconductor with a high mobility 10 6 cm 2 /V.S. The Hall coefficient R H was measured as a function of magnetic field strength H for a number of samples of both p and n-type using fields up to 12 kilo gauss. The Hall coefficient R h decreases with increasing magnetic fields as well as with increase in temperature of the sample. The electric field is more effective on samples with high mobilities and consequently the deviations from linearity are manifested at comparatively low values of the electric field. The measurement of R H in weak and strong magnetic fields makes it possible to determine the separate concentration of heavy and light holes. Measured values of Hall coefficient and electrical resistivity show that there is a little variation of ρ and R h with temperatures as well as with magnetic fields. (author). 12 refs., 5 tabs

  19. High resolution in-operando microimaging of solar cells with pulsed electrically-detected magnetic resonance

    Science.gov (United States)

    Katz, Itai; Fehr, Matthias; Schnegg, Alexander; Lips, Klaus; Blank, Aharon

    2015-02-01

    The in-operando detection and high resolution spatial imaging of paramagnetic defects, impurities, and states becomes increasingly important for understanding loss mechanisms in solid-state electronic devices. Electron spin resonance (ESR), commonly employed for observing these species, cannot meet this challenge since it suffers from limited sensitivity and spatial resolution. An alternative and much more sensitive method, called electrically-detected magnetic resonance (EDMR), detects the species through their magnetic fingerprint, which can be traced in the device's electrical current. However, until now it could not obtain high resolution images in operating electronic devices. In this work, the first spatially-resolved electrically-detected magnetic resonance images (EDMRI) of paramagnetic states in an operating real-world electronic device are provided. The presented method is based on a novel microwave pulse sequence allowing for the coherent electrical detection of spin echoes in combination with powerful pulsed magnetic-field gradients. The applicability of the method is demonstrated on a device-grade 1-μm-thick amorphous silicon (a-Si:H) solar cell and an identical device that was degraded locally by an electron beam. The degraded areas with increased concentrations of paramagnetic defects lead to a local increase in recombination that is mapped by EDMRI with ∼20-μm-scale pixel resolution. The novel approach presented here can be widely used in the nondestructive in-operando three-dimensional characterization of solid-state electronic devices with a resolution potential of less than 100 nm.

  20. Non-invasive electrical and magnetic stimulation of the brain, spinal cord, roots and peripheral nerves

    DEFF Research Database (Denmark)

    Rossini, P M; Burke, D; Chen, R

    2015-01-01

    These guidelines provide an up-date of previous IFCN report on "Non-invasive electrical and magnetic stimulation of the brain, spinal cord and roots: basic principles and procedures for routine clinical application" (Rossini et al., 1994). A new Committee, composed of international experts, some...