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Sample records for rotating electromagnetic field

  1. Analytical model for electromagnetic cascades in rotating electric field

    SciTech Connect

    Nerush, E. N.; Bashmakov, V. F.; Kostyukov, I. Yu.

    2011-08-15

    Electromagnetic cascades attract a lot of attention as an important quantum electrodynamics effect that will reveal itself in various electromagnetic field configurations at ultrahigh intensities. We study cascade dynamics in rotating electric field analytically and numerically. The kinetic equations for the electron-positron plasma and gamma-quanta are formulated. The scaling laws are derived and analyzed. For the cascades arising far above the threshold the dependence of the cascade parameters on the field frequency is derived. The spectra of high-energy cascade particles are calculated. The analytical results are verified by numerical simulations.

  2. The use of the rotating electromagnetic field for hardening treatment of details

    NASA Astrophysics Data System (ADS)

    Lebedev, V. A.; Kochubey, A. A.; Kiricheck, A. V.

    2017-02-01

    The article discusses energy aspects of details’ hardening with convective flows of freely moving indenters under the conditions of the rotating electromagnetic field. Results of theoretical studies of the kinetics of the movement of the ferromagnetic indenters are presented and the energy model of the state of the rotating magnetic liquefied layer is proposed, formed under the influence of the rotating electromagnetic field.

  3. Consequences of rotating off-centred dipolar electromagnetic field in vacuum around Pulsars

    NASA Astrophysics Data System (ADS)

    Kundu, A.; Pétri, J.

    2016-12-01

    Studying the electromagnetic field of pulsars is one of the key themes in neutron star physics. While most of the works assume a standard central dipolar electromagnetic field model, recently some efforts had been made in explaining how inclusion of higher field components produces drastic consequences in our understanding of these objects. We put forward the effects of a unique recently presented approach in which the magnetic axis is shifted off from the centre. It is found that the rotating off-centred dipolar electromagnetic field itself reveals the presence of the higher components within. The consequences of this approach on the shape of the polar caps and the emission diagrams are discussed.

  4. Continuum resonance induced electromagnetic torque by a rotating plasma response to static resonant magnetic perturbation field

    SciTech Connect

    Liu Yueqiang; Connor, J. W.; Cowley, S. C.; Ham, C. J.; Hastie, R. J.; Hender, T. C.

    2012-10-15

    A numerical study is carried out, based on a simple toroidal tokamak equilibrium, to demonstrate the radial re-distribution of the electromagnetic torque density, as a result of a rotating resistive plasma (linear) response to a static resonant magnetic perturbation field. The computed electromagnetic torque peaks at several radial locations even in the presence of a single rational surface, due to resonances between the rotating response, in the plasma frame, and both Alfven and sound continuum waves. These peaks tend to merge together to form a rather global torque distribution, when the plasma resistivity is large. The continuum resonance induced net electromagnetic torque remains finite even in the limit of an ideal plasma.

  5. Study on Metal Detection with an Electromagnetic Induction Probe Utilizing a Rotating Magnetic Field

    NASA Astrophysics Data System (ADS)

    Koyama, Kiyoshi; Hoshikawa, Hiroshi; Sakon, Toshikazu

    The present paper describes an investigation conducted on metal detection with a scanning probe. The authors applied a rotating magnetic field probe to metal detection. The rotating magnetic field probe is composed of two vertically placed rectangular exciting coils and a circular detecting coil. The experimental results confirmed that the probe can detect metal objects and provide more information about their shape, direction, and electromagnetic characteristics than conventional metal detector probes. A two-dimensional signal display shows a blurred image of the metal object and the signal phase indicates the object's direction and electromagnetic characteristics. The experimental results showed that excellent restoration of the surface shapes of metal objects can be obtained for both magnetic and nonmagnetic metals under present conditions. There is also a possibility that the rough shape of a metal object can be estimated from the restored image.

  6. Electromagnetic rotational actuation.

    SciTech Connect

    Hogan, Alexander Lee

    2010-08-01

    There are many applications that need a meso-scale rotational actuator. These applications have been left by the wayside because of the lack of actuation at this scale. Sandia National Laboratories has many unique fabrication technologies that could be used to create an electromagnetic actuator at this scale. There are also many designs to be explored. In this internship exploration of the designs and fabrications technologies to find an inexpensive design that can be used for prototyping the electromagnetic rotational actuator.

  7. Electromagnetic fields generated by constrained rotation of structural blocks in the Earth’s crust

    NASA Astrophysics Data System (ADS)

    Losseva, T. V.; Kuzmicheva, M. Y.; Spivak, A. A.

    2009-12-01

    Specific features of low frequency electromagnetic impulses in the subsurface Earth’s crust with a low moisture content are defined by the tectonic activity of the region and its structure as well as the stressed-strained state. Electromagnetic effects related to seismic and deformation processes in rocks are very diverse and their physical nature is different. The electric polarization of rocks deserves special attention, since this mechanism is implied in an explosive loading of rocks or relaxation processes in any hierarchic block geophysical medium [1]. The amplitudes of electromagnetic pulses generated by electric currents in a relaxing block-structured stress-strained medium have been obtained by 3D numerical modeling. The source of currents is formed by electric polarization of solids filled inter-block gaps on the active face of a block which, in turn, rotates constrainedly under relaxation. The electric current impulse is defined by the shape of the seismic impulse of the block under relaxation. The block is embedded in the crust. The full system of Maxwell equations in a conductive medium has been solved. The numerical method used has been developed to describe properly the geometry of strain as well as impressed current and conductivity profiles at every time. The figure below presents the maximal amplitudes of electric fields Emax for different active block sizes L (curves 1, 2, 3) versus the relative distances from the source epicenter x/L. Here circles denote the experimental data obtained for the Kurai tectonic structure [1]. We see that the results of numerical simulations are in good agreement with the results of measurements. This proves the validity of our model for the estimation of electric effects in the low moisture rock medium. References: [1] S.P. Soloviev and A.A. Spivak, Doklady Earth Sciences, 2007, Vol. 417A, No. 9, pp. 1449-1453.

  8. Causal extraction of black hole rotational energy by various kinds of electromagnetic fields

    SciTech Connect

    Koide, Shinji; Baba, Tamon

    2014-09-10

    Recent general relativistic magnetohydrodynamics (MHD) simulations have suggested that relativistic jets from active galactic nuclei (AGNs) have been powered by the rotational energy of central black holes. Some mechanisms for extraction of black hole rotational energy have been proposed, like the Penrose process, Blandford-Znajek mechanism, MHD Penrose process, and superradiance. The Blandford-Znajek mechanism is the most promising mechanism for the engines of the relativistic jets from AGNs. However, an intuitive interpretation of this mechanism with causality is not yet clarified, while the Penrose process has a clear interpretation for causal energy extraction from a black hole with negative energy. In this paper, we present a formula to build physical intuition so that in the Blandford-Znajek mechanism, as well as in other electromagnetic processes, negative electromagnetic energy plays an important role in causal extraction of the rotational energy of black holes.

  9. Causal signal transmission by quantum fields. V: Generalised Keldysh rotations and electromagnetic response of the Dirac sea

    SciTech Connect

    Plimak, L.I.; Stenholm, S.

    2012-11-15

    The connection between real-time quantum field theory (RTQFT) [see, e.g., A. Kamenev and A. Levchenko, Adv. Phys. 58 (2009) 197] and phase-space techniques [E. Wolf and L. Mandel, Optical Coherence and Quantum Optics (Cambridge, 1995)] is investigated. The Keldysh rotation that forms the basis of RTQFT is shown to be a phase-space mapping of the quantum system based on the symmetric (Weyl) ordering. Following this observation, we define generalised Keldysh rotations based on the class of operator orderings introduced by Cahill and Glauber [K.E. Cahill, R.J. Glauber, Phys. Rev. 177 (1969) 1882]. Each rotation is a phase-space mapping, generalising the corresponding ordering from free to interacting fields. In particular, response transformation [L.I. Plimak, S. Stenholm, Ann. Phys. (N.Y.) 323 (2008) 1989] extends the normal ordering of free-field operators to the time-normal ordering of Heisenberg operators. Structural properties of the response transformation, such as its association with the nonlinear quantum response problem and the related causality properties, hold for all generalised Keldysh rotations. Furthermore, we argue that response transformation is especially suited for RTQFT formulation of spatial, in particular, relativistic, problems, because it extends cancellation of zero-point fluctuations, characteristic of the normal ordering, to interacting fields. As an example, we consider quantised electromagnetic field in the Dirac sea. In the time-normally-ordered representation, dynamics of the field looks essentially classical (fields radiated by currents), without any contribution from zero-point fluctuations. For comparison, we calculate zero-point fluctuations of the interacting electromagnetic field under orderings other than time-normal. The resulting expression is physically inconsistent: it does not obey the Lorentz condition, nor Maxwell's equations. - Highlights: Black-Right-Pointing-Pointer The Keldysh rotation is a phase-space mapping based on

  10. Sur l'expression du tenseur diélectrique du plasma dans un champ electromagnétique en rotation On the expression of the dielectric tensor of a plasma in a rotating electromagnetic field

    NASA Astrophysics Data System (ADS)

    Lofo, L. B.; Kazadi, M. B.

    1996-10-01

    The influence of a rotating electromagnetic field on the expression of the dielectric tensor of a fully ionized plasma is presented. Our tensor differs from the Klimontovich's expression obtained for the case of a constant magnetic field by the presence of a new term due to the rotating electromagnetic field. It is also shown that three components have changed the positions they previously occupied in Klimontovich's expression.

  11. Introducing Electromagnetic Field Momentum

    ERIC Educational Resources Information Center

    Hu, Ben Yu-Kuang

    2012-01-01

    I describe an elementary way of introducing electromagnetic field momentum. By considering a system of a long solenoid and line charge, the dependence of the field momentum on the electric and magnetic fields can be deduced. I obtain the electromagnetic angular momentum for a point charge and magnetic monopole pair partially through dimensional…

  12. Electromagnetic instabilities in rotating magnetized viscous objects

    NASA Astrophysics Data System (ADS)

    Nekrasov, A. K.

    2009-12-01

    In this paper, we study electromagnetic streaming instabilities in the thermal viscous regions of rotating astrophysical objects, such as magnetized accretion discs, molecular clouds, their cores and elephant trunks. The results obtained can also be applied to any regions of interstellar medium, where different equilibrium velocities between charged species can arise. We consider a weakly ionized multicomponent plasma consisting of neutrals and magnetized electrons, ions and dust grains. We take into account the effect of perturbation of collisional frequencies as a result of the density perturbations of species. We obtain general expressions for the perturbed velocities of species involving the thermal pressure and viscosity when perturbations propagate perpendicular to the background magnetic field. The dispersion relation is derived and investigated for axisymmetric perturbations. New compressible instabilities generated as a result of different equilibrium velocities of different charged species are found in the cold and thermal limits either when the viscosity of neutrals can be neglected or when it is important. The viscosity of magnetized charged species is negligible for the perturbations considered that have wavelengths much larger than the Larmor radius of species. At the same time, the neutrals are shown to be immobile in electromagnetic perturbations when their viscosity is sufficiently large.

  13. Intrinsic parallel rotation drive by electromagnetic ion temperature gradient turbulence

    NASA Astrophysics Data System (ADS)

    Peng, Shuitao; Wang, Lu; Pan, Yuan

    2017-03-01

    The quasilinear intrinsic parallel flow drive including parallel residual stress, kinetic stress, cross Maxwell stress and parallel turbulent acceleration by electromagnetic ion temperature gradient (ITG) turbulence is calculated analytically using electromagnetic gyrokinetic theory. Both the kinetic stress and cross Maxwell stress also enter the mean parallel flow velocity equation via their divergence, as for the usual residual stress. The turbulent acceleration driven by ion pressure gradient along the total magnetic field (including equilibrium magnetic field and fluctuating radial magnetic field) cannot be written as a divergence of stress, and so should be treated as a local source/sink. All these terms can provide intrinsic parallel rotation drive. Electromagnetic effects reduce the non-resonant electrostatic stress force and even reverse it, but enhance the resonant stress force. Both the non-resonant and resonant turbulent acceleration terms are also enhanced by electromagnetic effects. The possible implications of our results for experimental observations are discussed.

  14. Electromagnetic Field Penetration Studies

    NASA Technical Reports Server (NTRS)

    Deshpande, M.D.

    2000-01-01

    A numerical method is presented to determine electromagnetic shielding effectiveness of rectangular enclosure with apertures on its wall used for input and output connections, control panels, visual-access windows, ventilation panels, etc. Expressing EM fields in terms of cavity Green's function inside the enclosure and the free space Green's function outside the enclosure, integral equations with aperture tangential electric fields as unknown variables are obtained by enforcing the continuity of tangential electric and magnetic fields across the apertures. Using the Method of Moments, the integral equations are solved for unknown aperture fields. From these aperture fields, the EM field inside a rectangular enclosure due to external electromagnetic sources are determined. Numerical results on electric field shielding of a rectangular cavity with a thin rectangular slot obtained using the present method are compared with the results obtained using simple transmission line technique for code validation. The present technique is applied to determine field penetration inside a Boeing-757 by approximating its passenger cabin as a rectangular cavity filled with a homogeneous medium and its passenger windows by rectangular apertures. Preliminary results for, two windows, one on each side of fuselage were considered. Numerical results for Boeing-757 at frequencies 26 MHz, 171-175 MHz, and 428-432 MHz are presented.

  15. Proca and electromagnetic fields

    SciTech Connect

    Hillion, P.; Quinnerz, S.

    1986-07-01

    In the framework of the proper orthochronous Lorentz group, the old connection is revived between the electromagnetic field characterized by a self-dual tensor and a traceless second-rank spinor obeying the Proca equation. The relationship between this spinor and the Hertz potential also considered as a self-dual tensor is emphasized. The extension of this formalism to meet the covariance under the full Lorentz group is also discussed.

  16. Carter separable electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Lynden-Bell, D.

    2000-02-01

    The purely electromagnetic analogue in flat space of Kerr's metric in general relativity is only rarely considered. Here we carry out in flat space a programme similar to Carter's investigation of metrics in general relativity in which the motion of a charged particle is separable. We concentrate on the separability of the motion (be it classical, relativistic or quantum) of a charged particle in electromagnetic fields that lie in planes through an axis of symmetry. In cylindrical polar coordinates (t,R,φ,z) the four-vector potential takes the form [formmu2] is the unit toroidal vector. The forms of the functions Φ(R,z) and A(R,z) are sought that allow separable motion. This occurs for relativistic motion only when AR,Φ and A2-Φ2 are all of the separable form ζ(λ)-η(μ)]/(λ-μ), where ζ and η are arbitrary functions, and λ and μ are spheroidal coordinates or degenerations thereof. The special forms of A and Φ that allow this are deduced. They include the Kerr metric analogue, with E+iB=-∇{q[(r-ia).(r-ia)]-1/2}. Rather more general electromagnetic fields allow separation when the motion is non-relativistic. The investigation is extended to fields that lie in parallel planes. Connections to Larmor's theorem are remarked upon.

  17. Translation and Rotation of Transformation Media under Electromagnetic Pulse

    PubMed Central

    Gao, Fei; Shi, Xihang; Lin, Xiao; Xu, Hongyi; Zhang, Baile

    2016-01-01

    It is well known that optical media create artificial geometry for light, and curved geometry acts as an effective optical medium. This correspondence originates from the form invariance of Maxwell’s equations, which recently has spawned a booming field called ‘transformation optics’. Here we investigate responses of three transformation media under electromagnetic pulses, and find that pulse radiation can induce unbalanced net force on transformation media, which will cause translation and rotation of transformation media although their final momentum can still be zero. Therefore, the transformation media do not necessarily stay the same after an electromagnetic wave passes through. PMID:27321246

  18. Translation and Rotation of Transformation Media under Electromagnetic Pulse

    NASA Astrophysics Data System (ADS)

    Gao, Fei; Shi, Xihang; Lin, Xiao; Xu, Hongyi; Zhang, Baile

    2016-06-01

    It is well known that optical media create artificial geometry for light, and curved geometry acts as an effective optical medium. This correspondence originates from the form invariance of Maxwell’s equations, which recently has spawned a booming field called ‘transformation optics’. Here we investigate responses of three transformation media under electromagnetic pulses, and find that pulse radiation can induce unbalanced net force on transformation media, which will cause translation and rotation of transformation media although their final momentum can still be zero. Therefore, the transformation media do not necessarily stay the same after an electromagnetic wave passes through.

  19. Coherent hybrid electromagnetic field imaging

    DOEpatents

    Cooke, Bradly J.; Guenther, David C.

    2008-08-26

    An apparatus and corresponding method for coherent hybrid electromagnetic field imaging of a target, where an energy source is used to generate a propagating electromagnetic beam, an electromagnetic beam splitting means to split the beam into two or more coherently matched beams of about equal amplitude, and where the spatial and temporal self-coherence between each two or more coherently matched beams is preserved. Two or more differential modulation means are employed to modulate each two or more coherently matched beams with a time-varying polarization, frequency, phase, and amplitude signal. An electromagnetic beam combining means is used to coherently combine said two or more coherently matched beams into a coherent electromagnetic beam. One or more electromagnetic beam controlling means are used for collimating, guiding, or focusing the coherent electromagnetic beam. One or more apertures are used for transmitting and receiving the coherent electromagnetic beam to and from the target. A receiver is used that is capable of square-law detection of the coherent electromagnetic beam. A waveform generator is used that is capable of generation and control of time-varying polarization, frequency, phase, or amplitude modulation waveforms and sequences. A means of synchronizing time varying waveform is used between the energy source and the receiver. Finally, a means of displaying the images created by the interaction of the coherent electromagnetic beam with target is employed.

  20. Electromagnetic Field Effects in Explosives

    NASA Astrophysics Data System (ADS)

    Tasker, D. G.; Whitley, V. H.; Lee, R. J.

    2009-12-01

    Present and previous research on the effects of electromagnetic fields on the initiation and detonation of explosives and the electromagnetic properties of explosives are reviewed. Among the topics related to detonating explosives are: enhancement of performance; and control of initiation and growth of reaction. Two series of experiments were performed to determine the effects of 1-T magnetic fields on explosive initiation and growth in the modified gap test and on the propagation of explosively generated plasma into air. The results have implications for the control of reactions in explosives and for the use of electromagnetic particle velocity gauges.

  1. Electromagnetic fields and public health.

    PubMed Central

    Aldrich, T E; Easterly, C E

    1987-01-01

    A review of the literature is provided for the topic of health-related research and power frequency electromagnetic fields. Minimal evidence for concern is present on the basis of animal and plant research. General observation would accord with the implication that there is no single and manifest health effect as the result of exposure to these fields. There are persistent indications, however, that these fields have biologic activity, and consequently, there may be a deleterious component to their action, possibly in the presence of other factors. Power frequency electromagnetic field exposures are essentially ubiquitous in modern society, and their implications in the larger perspective of public health are unclear at this time. Electromagnetic fields represent a methodological obstacle for epidemiologic studies and a quandary for risk assessment; there is need for more data. PMID:3319560

  2. String theory in electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Ambjørn, Jan; Makeenko, Yuri M.; Semenoff, Gordon W.; Szabo, Richard J.

    2003-02-01

    A review of various aspects of superstrings in background electromagnetic fields is presented. Topics covered include the Born-Infeld action, spectrum of open strings in background gauge fields, the Schwinger mechanism, finite-temperature formalism and Hagedorn behaviour in external fields, Debye screening, D-brane scattering, thermodynamics of D-branes, and noncommutative field and string theories on D-branes. The electric field instabilities are emphasized throughout and contrasted with the case of magnetic fields. A new derivation of the velocity-dependent potential between moving D-branes is presented, as is a new result for the velocity corrections to the one-loop thermal effective potential.

  3. Explanations, Education, and Electromagnetic Fields.

    ERIC Educational Resources Information Center

    Friedman, Sharon M.

    Explaining complex scientific and environmental subjects in the mass media is difficult to do, particularly under such constraints as short deadlines and lack of space or time. When a scientific controversy and human health risk are involved, this becomes an even harder task to accomplish. The subject of electromagnetic fields (EMF) involves…

  4. What Are Electromagnetic Fields?

    MedlinePlus

    ... will generate a single big wave; more rapid motion will generate a whole series of small waves. ... are hardly detectable. Magnetic fields arise from the motion of electric charges. The strength of the magnetic ...

  5. Rotating superconductor magnet for producing rotating lobed magnetic field lines

    DOEpatents

    Hilal, Sadek K.; Sampson, William B.; Leonard, Edward F.

    1978-01-01

    This invention provides a rotating superconductor magnet for producing a rotating lobed magnetic field, comprising a cryostat; a superconducting magnet in the cryostat having a collar for producing a lobed magnetic field having oppositely directed adjacent field lines; rotatable support means for selectively rotating the superconductor magnet; and means for energizing the superconductor magnet.

  6. Extremely low frequency electromagnetic fields

    SciTech Connect

    Wilson, B.W. . Chemical Sciences Dept.); Stevens, R.G. ); Anderson, L.E. . Life Sciences Center)

    1990-01-01

    The authors focus on that which seems to be the central scientific issue emerging from current ELF research in epidemiology and in the laboratory; namely, can ELF electromagnetic fields interact with biological systems in such a way as to increase cancer risk The authors examine how cancer risk might be related to two reproducible biological effects of ELF exposure: effects on the pineal gland and circadian biology, and effects on calcium homeostasis in cells. Because they are concerned with the possible biological mechanisms of carcinogenesis, epidemiological studies are only briefly reviewed.

  7. Electromagnetic fields in cased borehole

    SciTech Connect

    Lee, Ki Ha; Kim, Hee Joon; Uchida, Toshihiro

    2001-07-20

    Borehole electromagnetic (EM) measurements, using fiberglass-cased boreholes, have proven useful in oil field reservoir characterization and process monitoring (Wilt et al., 1995). It has been presumed that these measurements would be impossible in steel-cased wells due to the very large EM attenuation and phase shifts. Recent laboratory and field studies have indicated that detection of EM signals through steel casing should be possible at low frequencies, and that these data provide a reasonable conductivity image at a useful scale. Thus, we see an increased application of this technique to mature oilfields, and an immediate extension to geothermal industry as well. Along with the field experiments numerical model studies have been carried out for analyzing the effect of steel casing to the EM fields. The model used to be an infinitely long uniform casing embedded in a homogeneous whole space. Nevertheless, the results indicated that the formation signal could be accurately recovered if the casing characteristics were independently known (Becker et al., 1998; Lee el al., 1998). Real steel-cased wells are much more complex than the simple laboratory models used in work to date. The purpose of this study is to develop efficient numerical methods for analyzing EM fields in realistic settings, and to evaluate the potential application of EM technologies to cross-borehole and single-hole environment for reservoir characterization and monitoring.

  8. NMR in rotating magnetic fields: Magic angle field spinning

    SciTech Connect

    Sakellariou, D.; Meriles, C.; Martin, R.; Pines, A.

    2004-09-10

    Magic angle sample spinning has been one of the cornerstones in high-resolution solid state NMR. Spinning frequencies nowadays have increased by at least one order of magnitude over the ones used in the first experiments and the technique has gained tremendous popularity. It is currently a routine procedure in solid-state NMR, high-resolution liquid-state NMR and solid-state MRI. The technique enhances the spectral resolution by averaging away rank 2 anisotropic spin interactions thereby producing isotropic-like spectra with resolved chemical shifts and scalar couplings. Andrew proposed that it should be possible to induce similar effects in a static sample if the direction of the magnetic field is varied, e.g., magic-angle rotation of the B0 field (B0-MAS) and this has been recently demonstrated using electromagnetic field rotation. Here we discuss on the possibilities to perform field rotation using alternative hardware, together with spectroscopic methods to recover isotropic resolution even in cases where the field is not rotating at the magic angle. Extension to higher magnetic fields would be beneficial in situations where the physical manipulation of the sample is inconvenient or impossible. Such situations occur often in materials or biomedical samples where ''ex-situ'' NMR spectroscopy and imaging analysis is needed.

  9. Electromagnetic field and brain development.

    PubMed

    Kaplan, Suleyman; Deniz, Omur Gulsum; Önger, Mehmet Emin; Türkmen, Aysın Pınar; Yurt, Kıymet Kübra; Aydın, Işınsu; Altunkaynak, Berrin Zuhal; Davis, Devra

    2016-09-01

    Rapid advances in technology involve increased exposures to radio-frequency/microwave radiation from mobile phones and other wireless transmitting devices. As cell phones are held close to the head during talking and often stored next to the reproductive organs, studies are mostly focused on the brain. In fact, more research is especially needed to investigate electromagnetic field (EMF)'s effects on the central nervous system (CNS). Several studies clearly demonstrate that EMF emitted by cell phones could affect a range of body systems and functions. Recent work has demonstrated that EMF inhibit the formation and differentiation of neural stem cells during embryonic development and also affect reproductive and neurological health of adults that have undergone prenatal exposure. The aim of this review is to discuss the developing CNS and explain potential impacts of EMF on this system.

  10. Electromagnetic field patterning or crystal light

    NASA Astrophysics Data System (ADS)

    Słupski, Piotr; Wymysłowski, Artur; Czarczyński, Wojciech

    2016-12-01

    Using the orbital angular momentum of light for the development of a vortex interferometer, the underlying physics requires microwave/RF models,1 as well as quantum mechanics for light1, 2 and fluid flow for semiconductor devices.3, 4 The combination of the aforementioned physical models yields simulations and results such as optical lattices,1 or an Inverse Farday effect.5 The latter is explained as the absorption of optical angular momentum, generating extremely high instantenous magnetic fields due to radiation friction. An algorithmic reduction across the computational methods used in microwaves, lasers, quantum optics and holography is performed in order to explain electromagnetic field interactions in a single computational framework. This work presents a computational model for photon-electron interactions, being a simplified gauge theory described using differentials or disturbances (photons) instead of integrals or fields. The model is based on treating the Z-axis variables as a Laplace fluid with spatial harmonics, and the XY plane as Maxwell's equations on boundaries. The result is a unified, coherent, graphical computational method of describing the photon qualitatively, quantitatively and with proportion. The model relies on five variables and is described using two equations, which use emitted power, cavity wavelength, input frequency, phase and time. Phase is treated as a rotated physical dimension under gauge theory of Feynmann's QED. In essence, this model allows the electromagnetic field to be treated with it's specific crystallography. The model itself is described in Python programming language. PACS 42.50.Pq, 31.30.J-, 03.70.+k, 11.10.-z, 67.10.Hk

  11. Noninvasive valve monitor using alternating electromagnetic field

    DOEpatents

    Eissenberg, David M.; Haynes, Howard D.; Casada, Donald A.

    1993-01-01

    One or more electrical coils are carefully located on the outside of a valve body. An alternating current passing through the coil(s) results in an alternating electromagnetic field being transmitted into the valve body and valve internals. The electromagnetic field varies in intensity and polarity in the valve. As the position of a valve internal part is changed, the electromagnetic field throughout the valve body and its internals is altered. A passive receiver coil carefully located on the outside of the valve body detects the intensity of the electromagnetic field at that location as an induced electrical voltage in the coil. With the change in position of the valve internal part, there is a corresponding change in the induced voltage as a result of the alteration in the alternating electromagnetic field at that location. Changes in the voltage provide an indication of the position and motion of valve internals.

  12. Noninvasive valve monitor using alternating electromagnetic field

    DOEpatents

    Eissenberg, D.M.; Haynes, H.D.; Casada, D.A.

    1993-03-16

    One or more electrical coils are carefully located on the outside of a valve body. An alternating current passing through the coil(s) results in an alternating electromagnetic field being transmitted into the valve body and valve internals. The electromagnetic field varies in intensity and polarity in the valve. As the position of a valve internal part is changed, the electromagnetic field throughout the valve body and its internals is altered. A passive receiver coil carefully located on the outside of the valve body detects the intensity of the electromagnetic field at that location as an induced electrical voltage in the coil. With the change in position of the valve internal part, there is a corresponding change in the induced voltage as a result of the alteration in the alternating electromagnetic field at that location. Changes in the voltage provide an indication of the position and motion of valve internals.

  13. Medical applications of electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Lai, Henry C.; Singh, Narendra P.

    2010-04-01

    In this article, we describe two possible applications of low-intensity non-ionizing electromagnetic fields (EMF) for the treatment of malaria and cancer, respectively. In malaria treatment, a low-intensity extremely-low frequency magnetic field can be used to induce vibration of hemozoin, a super-paramagnetic polymer particle, inside malaria parasites. This disturbance could cause free radical and mechanical damages leading to the death of the parasite. This concept has been tested in vitro on malaria parasites and found to be effective. This may provide a low cost effective treatment for malaria infection in humans. The rationale for cancer treatment using low-intensity EMF is based on two concepts that have been well established in the literature: (1) low-intensity non-thermal EMF enhances cytotoxic free radicals via the iron-mediated Fenton reaction; and (2) cancer cells have higher amounts of free iron, thus are more susceptible to the cytotoxic effects of EMF. Since normal cells contain minimal amount of free iron, the effect would be selectively targeting cancer cells. Thus, no adverse side effect would be expected as in traditional chemotherapy and radiation therapy. This concept has also been tested on human cancer cell and normal cells in vitro and proved to be feasible.

  14. Generating highly uniform electromagnetic field characteristics

    DOEpatents

    Crow, James T.

    1997-01-01

    An apparatus and method for generating homogenous electromagnetic fields within a volume. The homogeneity provided may be for magnetic and/or electric fields, and for field magnitude, radial gradient, or higher order radial derivative. The invention comprises conductive pathways oriented mirror symmetrically about a desired region of homogeneity. A corresponding apparatus and method is provided for substantially cancelling the electromagnetic field outside of the apparatus, comprising a second set of conductive pathways placed outside the first set.

  15. Generating highly uniform electromagnetic field characteristics

    DOEpatents

    Crow, James Terry

    1998-01-01

    An apparatus and method for generating homogenous electromagnetic fields within a volume. The homogeneity provided may be for magnetic and/or electric fields, and for field magnitude, radial gradient, or higher order radial derivative. The invention comprises conductive pathways oriented mirror symmetrically about a desired region of homogeneity. A corresponding apparatus and method is provided for substantially canceling the electromagnetic field outside of the apparatus, comprising a second set of conductive pathways placed outside the first set.

  16. Generating highly uniform electromagnetic field characteristics

    DOEpatents

    Crow, J.T.

    1998-02-10

    An apparatus and method for generating homogeneous electromagnetic fields within a volume is disclosed. The homogeneity provided may be for magnetic and/or electric fields, and for field magnitude, radial gradient, or higher order radial derivative. The invention comprises conductive pathways oriented mirror symmetrically about a desired region of homogeneity. A corresponding apparatus and method is provided for substantially canceling the electromagnetic field outside of the apparatus, comprising a second set of conductive pathways placed outside the first set. 39 figs.

  17. Generating highly uniform electromagnetic field characteristics

    DOEpatents

    Crow, J.T.

    1997-06-24

    An apparatus and method are disclosed for generating homogeneous electromagnetic fields within a volume. The homogeneity provided may be for magnetic and/or electric fields, and for field magnitude, radial gradient, or higher order radial derivative. The invention comprises conductive pathways oriented mirror symmetrically about a desired region of homogeneity. A corresponding apparatus and method is provided for substantially canceling the electromagnetic field outside of the apparatus, comprising a second set of conductive pathways placed outside the first set. 26 figs.

  18. Generating highly uniform electromagnetic field characteristics

    DOEpatents

    Crow, James T.

    1998-01-01

    An apparatus and method for generating homogenous electromagnetic fields within a volume. The homogeneity provided may be for magnetic and/or electric fields, and for field magnitude, radial gradient, or higher order radial derivative. The invention comprises conductive pathways oriented about a desired region of homogeneity. A corresponding apparatus and method is provided for substantially canceling the electromagnetic field outside of the apparatus, comprising a second set of conductive pathways placed outside the first set.

  19. Generating highly uniform electromagnetic field characteristics

    DOEpatents

    Crow, J.T.

    1998-05-05

    An apparatus and method are disclosed for generating homogeneous electromagnetic fields within a volume. The homogeneity provided may be for magnetic and/or electric fields, and for field magnitude, radial gradient, or higher order radial derivative. The invention comprises conductive pathways oriented about a desired region of homogeneity. A corresponding apparatus and method is provided for substantially canceling the electromagnetic field outside of the apparatus, comprising a second set of conductive pathways placed outside the first set. 55 figs.

  20. Nanomechanical electric and electromagnetic field sensor

    DOEpatents

    Datskos, Panagiotis George; Lavrik, Nickolay

    2015-03-24

    The present invention provides a system for detecting and analyzing at least one of an electric field and an electromagnetic field. The system includes a micro/nanomechanical oscillator which oscillates in the presence of at least one of the electric field and the electromagnetic field. The micro/nanomechanical oscillator includes a dense array of cantilevers mounted to a substrate. A charge localized on a tip of each cantilever interacts with and oscillates in the presence of the electric and/or electromagnetic field. The system further includes a subsystem for recording the movement of the cantilever to extract information from the electric and/or electromagnetic field. The system further includes a means of adjusting a stiffness of the cantilever to heterodyne tune an operating frequency of the system over a frequency range.

  1. Interaction of electromagnetic fields and biological tissues

    NASA Astrophysics Data System (ADS)

    Darshan Shrivastava, Bhakt; Barde, Ravindra; Mishra, Ashutosh; Phadke, S.

    2014-09-01

    This paper deals with the electromagnetic field interact in biological tissues. It is actually one of the important challenges for the electromagnetic field for the recent years. The experimental techniques are use in Broad-band Dielectric Measurement (BDM) with LCR meters. The authors used Bones and scales of Fish taken from Narmada River (Rajghat Dist. Barwani) as biological tissues. Experimental work carried out done in inter-university consortium (IUC) Indore. The major difficulties that appear are related to the material properties, to the effect of the electromagnetic problem and to the thermal model of the biological tissues.

  2. Narrow field electromagnetic sensor system and method

    DOEpatents

    McEwan, Thomas E.

    1996-01-01

    A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments.

  3. Narrow field electromagnetic sensor system and method

    DOEpatents

    McEwan, T.E.

    1996-11-19

    A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments. 12 figs.

  4. Transient Simulation of a Rotating Conducting Cylinder in a Transverse Magnetic Field

    DTIC Science & Technology

    2016-09-01

    field. The factors that affect the magnetic field inside the cylinder were analyzed by varying the spin rate and the electromagnetic physical...rotation were evaluated. The analysis results indicated that the magnetic field inside the cylinder was affected by the spin rate and the electromagnetic ...TABLES 1 Electromagnetic properties 3 2 Spin rates and angular frequency 4 3 Phase shift angle of magnetic flux density vector at center of

  5. Program For Displaying Computed Electromagnetic Fields

    NASA Technical Reports Server (NTRS)

    Hom, Kam W.

    1995-01-01

    EM-ANIMATE computer program specialized visualization displays and animates output data on near fields and surface currents computed by electromagnetic-field program - in particular MOM3D (LAR-15074). Program based on windows and contains user-friendly, graphical interface for setting viewing options, selecting cases, manipulating files, and like. Written in FORTRAN 77. EM-ANIMATE also available as part of package, COS-10048, includes MOM3D, IRIS program computing near-field and surface-current solutions of electromagnetic-field equations.

  6. Controlling the Electromagnetic Field Confinement with Metamaterials

    PubMed Central

    Bonache, Jordi; Zamora, Gerard; Paredes, Ferran; Zuffanelli, Simone; Aguilà, Pau; Martín, Ferran

    2016-01-01

    The definition of a precise illumination region is essential in many applications where the electromagnetic field should be confined in some specific volume. By using conventional structures, it is difficult to achieve an adequate confinement distance (or volume) with negligible levels of radiation leakage beyond it. Although metamaterial structures and metasurfaces are well-known to provide high controllability of their electromagnetic properties, this feature has not yet been applied to solve this problem. We present a method of electromagnetic field confinement based on the generation of evanescent waves by means of metamaterial structures. With this method, the confinement volume can be controlled, namely, it is possible to define a large area with an intense field without radiation leakage. A prototype working in the microwave region has been implemented, and very good agreement between the measurements and the theoretical prediction of field distribution has been obtained. PMID:27886230

  7. Controlling the Electromagnetic Field Confinement with Metamaterials

    NASA Astrophysics Data System (ADS)

    Bonache, Jordi; Zamora, Gerard; Paredes, Ferran; Zuffanelli, Simone; Aguilà, Pau; Martín, Ferran

    2016-11-01

    The definition of a precise illumination region is essential in many applications where the electromagnetic field should be confined in some specific volume. By using conventional structures, it is difficult to achieve an adequate confinement distance (or volume) with negligible levels of radiation leakage beyond it. Although metamaterial structures and metasurfaces are well-known to provide high controllability of their electromagnetic properties, this feature has not yet been applied to solve this problem. We present a method of electromagnetic field confinement based on the generation of evanescent waves by means of metamaterial structures. With this method, the confinement volume can be controlled, namely, it is possible to define a large area with an intense field without radiation leakage. A prototype working in the microwave region has been implemented, and very good agreement between the measurements and the theoretical prediction of field distribution has been obtained.

  8. Electromagnetic fields in bone repair and adaptation

    NASA Astrophysics Data System (ADS)

    McLeod, Kenneth J.; Rubin, Clinton T.; Donahue, Henry J.

    1995-01-01

    The treatment of delayed union of bone fractures has served for the past 20 years as the principal testing ground for determining whether nonionizing electromagnetic fields can have any substantial, long-term effects in clinical medicine. Recent double-blinded clinical trials have confirmed the significance of the reported effects on bone healing and have led to the suggestion that electromagnetic fields may also be useful in the treatment of other orthopedic problems such as fresh fractures, stabilization of prosthetic implants, or even the prevention or treatment of osteoporosis. However, the design of appropriate treatment regimens for these new applications would be greatly facilitated if it were understood how the biological cells within bone tissue sense these low-frequency, and remarkably low level, electromagnetic fields. Here we address the engineering and physical science aspects of this problem. We review the characteristics of clinically used electromagnetic fields and discuss which components of these fields may actually be responsible for altering the activity of the bone cells. We then consider several physical mechanisms which have been proposed to explain how the cells within the bone or fracture tissue detect this field component.

  9. Electromagnetic field interactions with biological systems

    SciTech Connect

    Frey, A.H. )

    1993-02-01

    This is a report on Symposia organized by the International Society for Bioelectricity and presented at the 1992 FASEB Meeting. The presentations summarized here were intended to provide a sampling of new and fruitful lines of research. The theme topics for the Symposia were cancer, neural function, cell signaling, pineal gland function, and immune system interactions. Living organisms are complex electrochemical systems that evolved over billions of years in a world with a relatively simple weak magnetic field and with few electromagnetic energy emitters. As is characteristic of living organisms, they interacted with and adapted to this environment of electric and magnetic fields. In recent years there has been a massive introduction of equipment that emits electromagnetic fields in an enormous range of new frequencies, modulations, and intensities. As living organisms have only recently found themselves immersed in this new and virtually ubiquitous environment, they have not had the opportunity to adapt to it. This gives biologists the opportunity to use these electromagnetic fields as probes to study the functioning of living systems. This is a significant opportunity, as new approaches to studying living systems so often provide the means to make great leaps in science. In recent years, a diversity of biologists have carried out experiments using electromagnetic fields to study the function of living cells and systems. This approach is now becoming quite fruitful and is yielding data that are advancing our knowledge in diverse areas of biology. 25 refs., 6 figs., 3 tabs.

  10. Study of Rotating-Wave Electromagnetic Modes for Applications in Space Exploration

    NASA Astrophysics Data System (ADS)

    Velazco, J. E.

    2016-08-01

    Rotating waves are circularly polarized electromagnetic wave fields that behave like traveling waves but have discrete resonant frequencies of standing waves. In JPL's Communications Ground Systems Section (333), we are making use of this peculiar type of electromagnetic modes to develop a new generation of devices and instruments for direct applications in space exploration. In this article, we present a straightforward analysis about the phase velocity of these wave modes. A derivation is presented for the azimuthal phase velocity of transverse magnetic rotating modes inside cylindrical cavity resonators. Computer simulations and experimental measurements are also presented that corroborate the theory developed. It is shown that the phase velocity of rotating waves inside cavity resonators increases with radial position within the cavity and decreases when employing higher-order operating modes. The exotic features of rotating modes, once better understood, have the potential to enable the implementation of a plethora of new devices that range from amplifiers and frequency multipliers to electron accelerators and ion thrusters.

  11. Radiated fields from an electromagnetic pulse simulator

    NASA Astrophysics Data System (ADS)

    Pelletier, M.; Delisle, G. Y.; Kashyap, S.

    Simulators of electromagnetic pulses allow generation within a limited time of very high-intensity fields such as those produced in a nuclear explosion. These fields can be radiated out of the test zone at a lower but nevertheless significant level; if the intensity of these fields is sufficiently high, damage to humans and electronic equipment can result. An evaluation of the potential danger of these simulator emissions requires knowledge of the amplitude, duration, and the energy of the radiated impulses. A technique is presented for calculating the fields radiated by a parallel-plane electromagnetic pulse simulator. The same method can also be applied to a rhombic type simulator. Sample numerical results are presented along with the calculations of the energy and power density and a discussion of the formation of the field in the frequency domain.

  12. Photon Propagation in Slowly Varying Electromagnetic Fields

    NASA Astrophysics Data System (ADS)

    Karbstein, F.

    2017-03-01

    Effective theory of soft photons in slowly varying electromagnetic background fields is studied at one-loop order in QED. This is of relevance for the study of all-optical signatures of quantum vacuum nonlinearity in realistic electromagnetic background fields as provided by high-intensity lasers. The central result derived in this article is a new analytical expression for the photon polarization tensor in two linearly polarized counterpropagating pulsed Gaussian laser beams. Treating the peak field strengths of both laser beams as free parameters, this field configuration can be considered as interpolating between the limiting cases of a purely right- or left-moving laser beam (if one of the peak field strengths is set equal to zero) and the standing-wave type scenario with two counter-propagating beams of equal strength.

  13. Flow Transitions in a Rotating Magnetic Field

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Mazuruk, K.

    1996-01-01

    Critical Rayleigh numbers have been measured in a liquid metal cylinder of finite height in the presence of a rotating magnetic field. Several different stability regimes were observed, which were determined by the values of the Rayleigh and Hartmann numbers. For weak rotating magnetic fields and small Rayleigh numbers, the experimental observations can be explained by the existence of a single non-axisymmetric meridional roll rotating around the cylinder, driven by the azimuthal component of the magnetic field. The measured dependence of rotational velocity on magnetic field strength is consistent with the existence of laminar flow in this regime.

  14. Electromagnetic field parameters and instrumentation

    NASA Astrophysics Data System (ADS)

    Sheppard, A. R.; Jones, R. A.; Stell, M. E.; Adey, W. R.; Bawin, S.

    1986-07-01

    We studied the effects of the electric and magnetic components of a Loran-C type waveform on three biological systems. Neurochemical assays of brain neurotransmitter substances indicate field-related changes in the levels of norepinephrine in the hippocampus and in the number and affinities of the opiate receptors in the cortex. Behavioral data showed that rats trained in an operant conditioning task did not reliably detect any electric field strength used. Biochemical data demonstrated that the Loran-C field did not modify basal ornithine decarboxylase activity in primary bone cells.

  15. LEM—electromagnetic fields measurement laboratory

    NASA Astrophysics Data System (ADS)

    Annino, A.; Falciglia, F.; Musumeci, F.; Oliveri, M.; Privitera, G.; Triglia, A.

    2000-04-01

    The widespread presence of electromagnetic waves and the relative problems regarding them have favored the constitution of the LEM at the DMFCI in Catania University, where competence has been developing in this sector for about 10 years. Full operativeness has been reached as far as the electromagnetic field measurements in anthropized environments are concerned. Other research will be undertaken as soon as further funds are available. Some problems connected with the perfecting of measurements instruments and the results of emission measurements of cellular telephones are presented.

  16. Gene transcription and electromagnetic fields

    SciTech Connect

    Henderson, A.S.

    1992-01-01

    Our overall aim is to obtain sufficient information to allow us to ultimately determine whether ELF EM field exposure is an initiating factor in neoplastic transformation and/or if exposure can mimic characteristics of the second-step counterpart in neoplastic disease. This aim is based on our previous findings that levels of some transcripts are increased in cells exposed to EM fields. While the research is basic in nature, the ramifications have bearing on the general safety of exposure to EM fields in industrial and everyday life. A large array of diverse biological effects are reported to occur as the result of exposure to elf EM fields, suggesting that the cell response to EM fields is at a basic level, presumably initiated by molecular and/or biophysical events at the cell membrane. The hypothesized route is a signal transduction pathway involving membrane calcium fluxes. Information flow resulting from signal transduction can mediate the induction of regulatory factors in the cell, and directly affect how transcription is regulated.

  17. Exposure of biological preparations to radiofrequency electromagnetic fields under low gravity.

    PubMed

    Jacquot, Jean Francois; le Bail, Jean-Luc; Bardet, Michel; Tabony, James

    2010-11-01

    There is interest as to whether the electromagnetic fields used in mobile radiotelephony might affect biological processes. Other weak fields such as gravity intervene in a number of physical and biological processes. Under appropriate in vitro conditions, the macroscopic self-organization of microtubules, a major cellular component, is triggered by gravity. We wished to investigate whether self-organization might also be affected by radiotelephone electromagnetic fields. Detecting a possible effect requires removing the obscuring effects triggered by gravity. A simple manner of doing this is by rotating the sample about the horizontal. However, if the external field does not also rotate with the sample, its possible effect might also be averaged down by rotation. Here, we describe an apparatus in which both the sample and an applied radiofrequency electromagnetic field (1.8 GHz) are stationary with respect to one another while undergoing horizontal rotation. The electromagnetic field profile within the apparatus has been measured and the apparatus tested by reproducing the in vitro behavior of microtubule preparations under conditions of weightlessness. Specific adsorption rates of electromagnetic energy within a sample are measured from the initial temperature rise the incident field causes. The apparatus can be readily adapted to expose samples to various other external fields and factors under conditions of weightlessness.

  18. Electromagnetic forward and inverse problems of non-rotating magnetoacoustic tomography with magnetic induction.

    PubMed

    Zhang, Yang; Liu, Guoqiang; Tao, Chunjing; Wang, Hao; He, Wenjing

    2009-01-01

    The analysis of electromagnetic forward and inverse problems is very important in the process of image reconstruction for magnetoacoustic tomography with magnetic induction (MAT-MI). A new analysis method was introduced in this paper. It breaks through some illogical supposes that the existing methods applied and can improve the spatial resolution of the image availably. Besides it can avoid rotating the static magnetic field which is very difficult to come true in application, therefore the development of MAT-MI technique can be promoted greatly. To test the validity of the new method, two test models were analyzed, and the availability of the method was demonstrated.

  19. Understanding possible electromagnetic counterparts to loud gravitational wave events: Binary black hole effects on electromagnetic fields

    SciTech Connect

    Palenzuela, Carlos; Lehner, Luis; Yoshida, Shin

    2010-04-15

    In addition to producing loud gravitational waves, the dynamics of a binary black hole system could induce emission of electromagnetic radiation by affecting the behavior of plasmas and electromagnetic fields in their vicinity. We study how the electromagnetic fields are affected by a pair of orbiting black holes through the merger. In particular, we show how the binary's dynamics induce a variability in possible electromagnetically induced emissions as well as an enhancement of electromagnetic fields during the late-merge and merger epochs. These time dependent features will likely leave their imprint in processes generating detectable emissions and can be exploited in the detection of electromagnetic counterparts of gravitational waves.

  20. Electromagnetic field of a linear antenna

    NASA Astrophysics Data System (ADS)

    Derby, Norman; Olbert, Stanislaw

    2008-11-01

    Animated computer simulations of the electric field of a radiating antenna can capture the attention of students in introductory electromagnetism courses and stimulate active discussions. The simulations raise questions not usually addressed in textbooks. In certain cases, some of the field lines appear to move toward the antenna, the speed of the field lines can change as they move, and the field lines exhibit strange behavior (circling or splitting) at certain points. Because their fields can be expressed in terms of elementary functions, animations of point dipole antennas are common, but animations showing the fields of antennas with more realistic lengths are not as common because analytical expressions for these fields are not as well known. We show that it is possible to derive analytical expressions in terms of elementary functions for the electromagnetic field of linear antennas of finite length. We draw attention to an open-source method for displaying the fine details within the field patterns and then give a general discussion of singular points and their motions, derive expressions for their location and phase velocity, and apply these results to some of the phenomena that are visible in visualizations of the fields of various antennas.

  1. Electromagnetic field induced biological effects in humans.

    PubMed

    Kaszuba-Zwoińska, Jolanta; Gremba, Jerzy; Gałdzińska-Calik, Barbara; Wójcik-Piotrowicz, Karolina; Thor, Piotr J

    2015-01-01

    Exposure to artificial radio frequency electromagnetic fields (EMFs) has increased significantly in recent decades. Therefore, there is a growing scientific and social interest in its influence on health, even upon exposure significantly below the applicable standards. The intensity of electromagnetic radiation in human environment is increasing and currently reaches astronomical levels that had never before experienced on our planet. The most influential process of EMF impact on living organisms, is its direct tissue penetration. The current established standards of exposure to EMFs in Poland and in the rest of the world are based on the thermal effect. It is well known that weak EMF could cause all sorts of dramatic non-thermal effects in body cells, tissues and organs. The observed symptoms are hardly to assign to other environmental factors occurring simultaneously in the human environment. Although, there are still ongoing discussions on non-thermal effects of EMF influence, on May 31, 2011--International Agency for Research on Cancer (IARC)--Agenda of World Health Organization (WHO) has classified radio electromagnetic fields, to a category 2B as potentially carcinogenic. Electromagnetic fields can be dangerous not only because of the risk of cancer, but also other health problems, including electromagnetic hypersensitivity (EHS). Electromagnetic hypersensitivity (EHS) is a phenomenon characterized by the appearance of symptoms after exposure of people to electromagnetic fields, generated by EHS is characterized as a syndrome with a broad spectrum of non-specific multiple organ symptoms including both acute and chronic inflammatory processes located mainly in the skin and nervous systems, as well as in respiratory, cardiovascular systems, and musculoskeletal system. WHO does not consider the EHS as a disease-- defined on the basis of medical diagnosis and symptoms associated with any known syndrome. The symptoms may be associated with a single source of EMF

  2. Electromagnetic fields in the exterior of an oscillating relativistic star - II. Electromagnetic damping

    NASA Astrophysics Data System (ADS)

    Rezzolla, Luciano; Ahmedov, Bobomurat J.

    2016-07-01

    An important issue in the asteroseismology of compact and magnetized stars is the determination of the dissipation mechanism which is most efficient in damping the oscillations when these are produced. In a linear regime and for low-multipolarity modes, these mechanisms are confined to either gravitational-wave or electromagnetic losses. We here consider the latter and compute the energy losses in the form of Poynting fluxes, Joule heating and Ohmic dissipation in a relativistic oscillating spherical star with a dipolar magnetic field in vacuum. While this approach is not particularly realistic for rapidly rotating stars, it has the advantage that it is fully analytic and that it provides expressions for the electric and magnetic fields produced by the most common modes of oscillation both in the vicinity of the star and far away from it. In this way, we revisit and extend to a relativistic context the classical estimates of McDermott et al. Overall, we find that general-relativistic corrections lead to electromagnetic damping time-scales that are at least one order of magnitude smaller than in Newtonian gravity. Furthermore, with the only exception of g (gravity) modes, we find that f (fundamental), p (pressure), i (interface) and s (shear) modes are suppressed more efficiently by gravitational losses than by electromagnetic ones.

  3. Electromagnetic field radiation model for lightning strokes to tall structures

    SciTech Connect

    Motoyama, H.; Janischewskyj, W.; Hussein, A.M.; Chisholm, W.A.; Chang, J.S.; Rusan, R.

    1996-07-01

    This paper describes observation and analysis of electromagnetic field radiation from lightning strokes to tall structures. Electromagnetic field waveforms and current waveforms of lightning strokes to the CN Tower have been simultaneously measured since 1991. A new calculation model of electromagnetic field radiation is proposed. The proposed model consists of the lightning current propagation and distribution model and the electromagnetic field radiation model. Electromagnetic fields calculated by the proposed model, based on the observed lightning current at the CN Tower, agree well with the observed fields at 2km north of the tower.

  4. Rotationally Vibrating Electric-Field Mill

    NASA Technical Reports Server (NTRS)

    Kirkham, Harold

    2008-01-01

    A proposed instrument for measuring a static electric field would be based partly on a conventional rotating-split-cylinder or rotating-split-sphere electric-field mill. However, the design of the proposed instrument would overcome the difficulty, encountered in conventional rotational field mills, of transferring measurement signals and power via either electrical or fiber-optic rotary couplings that must be aligned and installed in conjunction with rotary bearings. Instead of being made to rotate in one direction at a steady speed as in a conventional rotational field mill, a split-cylinder or split-sphere electrode assembly in the proposed instrument would be set into rotational vibration like that of a metronome. The rotational vibration, synchronized with appropriate rapid electronic switching of electrical connections between electric-current-measuring circuitry and the split-cylinder or split-sphere electrodes, would result in an electrical measurement effect equivalent to that of a conventional rotational field mill. A version of the proposed instrument is described.

  5. [Safety and electromagnetic compatibility in sanitary field].

    PubMed

    Bini, M; Feroldi, P; Ferri, C; Ignesti, A; Olmi, R; Priori, S; Riminesi, C; Tobia, L

    2012-01-01

    In sanitary field and especially in a hospital, multiple sources of non ionizing radiation are used for diagnostic and therapeutic aims. In sanitary sector both workers and users are present at the same time, and in some cases general population could need higher protection than workers in relationship to the exposition to electromagnetic fields. In order to protect health and safety of patients, general population and workers of hospitals and with the aim to identify, analyze, evaluate and study its level of significance, electrical, magnetic and electromagnetic sources Research Italian project Si.C.E.O. (Safety And Electromagnetic Compatibility In Sanitary Field) was instituted. Target of our research project was to deepen risk of exposition elements with analysis of outdoor (e.g. power lines, transmission cabinets) and indoor (e.g. equipment for physical therapy) sources, located in sanitary structures and to verify the level exposition of workers and common population end the respect of specific regulation, and finally to define technical and organizational measures really useful for protection and reduction of risk.

  6. Dynamics of Cometary Dust Particles in Electromagnetic Radiation Fields

    NASA Astrophysics Data System (ADS)

    Herranen, Joonas; Markkanen, Johannes; Penttilä, Antti; Muinonen, Karri

    2016-10-01

    The formation of cometary dust tails and comae is based on solar radiation pressure. The pressure effects of electromagnetic radiation were originally conceptualized in Kepler's observations of the tails of comets and formulated mathematically by Maxwell in 1873. Today, the dynamics of cometary dust are known to be governed by gravity, electromagnetic forces, drag, solar wind, and solar radiation pressure.Solar radiation pressure has its roots in absorption, emission, and scattering of electromagnetic radiation. Due to modern advances in so-called integral equation methods in electromagnetics, a new approach of studying the effect of radiation pressure on cometary dust dynamics can be constructed. We solve the forces and torques due to radiation pressure for an arbitrarily shaped dust particle using volume integral equation methods.We then present a framework for solving the equations of motion of cometary dust particles due to radiative interactions. The solution is studied in a simplified cometary environment, where the radiative effects are studied at different orbits. The rotational and translational equations of motion are solved directly using a quaternion-based integrator. The rotational and translational equations of motion affect dust particle alignment and concentration. This is seen in the polarization of the coma. Thus, our direct dynamical approach can be used in modelling the observed imaging photo-polarimetry of the coma.In future studies, the integrator can be further extended to an exemplary comet environment, taking into account the drag, and the electric and magnetic fields. This enables us to study the dynamics of a single cometary dust particle based on fundamental physics.Acknowledgments. Research supported, in part, bythe European Research Council (ERC, grant Nr. 320773).

  7. Nested Helmholtz coil design for producing homogeneous transient rotating magnetic fields.

    PubMed

    Podaru, George; Moore, John; Dani, Raj Kumar; Prakash, Punit; Chikan, Viktor

    2015-03-01

    Electromagnets that can produce strong rotating magnetic fields at kHz frequencies are potentially very useful to exert rotating force on magnetic nanoparticles as small as few nanometers in size. In this article, the construction of a pulsed high-voltage rotating electromagnet is demonstrated based on a nested Helmholtz coil design. The energy for the coils is provided by two high-voltage discharge capacitors. The triggered spark gaps used in the experiments show sufficient accuracy to achieve the high frequency rotating magnetic field. The measured strength of the rotating magnetic field is 200 mT. This magnetic field is scalable by increasing the number of turns on the coils, by reducing the dimensions of the coils and by increasing the discharge current/voltage of the capacitors.

  8. A New Theory of the Electromagnetic Field

    NASA Astrophysics Data System (ADS)

    Kriske, Richard

    2017-01-01

    This author has previously introduced a new theory of the Electromagnetic Field and its interaction with matter. There was from the start a problem with Einstein's formulation of Invariants and its use in describing The EM field. The photon produced by first varying a stationary Electric field in one observer's reference frame is not the same as a photon produced from varying the a stationary Magnetic Field. The Magnetic field photon is thought of as being ``off the mass shell''. The Quantum information seems to carry with it an ordering of these events. You see this ordering in Wick's theory and in Feynman diagrams. This author is proposing that other fields can vary first in another Observers reference frame, not just the ``Scalar Field'' or the ``Fermion Field'', but many other forms of Energy. If the ``Nuclear Field'' varies first, it results in Quantum information that produces a photon that has the Nuclear Field in it and also the Magnetic Field, this is the strange effect seen in Nuclear Magnetic Resonance. This author proposed that there is a large number of photons with different properties, because of this ordering of events that occurs in Quantum Information. One of these photons is the Neutrino which appears to be a three field photon. This is Kriske's Field Theory.

  9. On electromagnetic field problems in inhomogeneous media

    NASA Technical Reports Server (NTRS)

    Mohsen, A.

    1973-01-01

    Analysis of electromagnetic fields in inhomogeneous media is of practical interest in general scattering and propagation problems and in the study of lenses. For certain types of inhomogeneities, the fields may be represented in terms of two scalars. In a general orthogonal coordinate system, these potentials satisfy second order differential equations. Exact solutions of these equations are known only for a few particular cases and in general, an approximate or numerical technique must be employed. The present work reviews and generalizes some of the main methods of attack of the problem. The results are presented in a form appropriate for numerical computation.

  10. Optimization methods in control of electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Angell, Thomas S.; Kleinman, Ralph E.

    1991-05-01

    This program is developing constructive methods for certain constrained optimization problems arising in the design and control of electromagnetic fields and in the identification of scattering objects. The problems addressed fall into three categories: (1) the design of antennas with optimal radiation characteristics measured in terms of directivity; (2) the control of the electromagnetic scattering characteristics of an object, in particular the minimization of its radar cross section, by the choice of material properties; and (3) the determination of the shape of scattering objects with various electromagnetic properties from scattered field data. The main thrust of the program is toward the development of constructive methods based on the use of complete families of solutions of the time-harmonic Maxwell equations in the infinite domain exterior to the radiating or scattering body. During the course of the work an increasing amount of attention has been devoted to the use of iterative methods for the solution of various direct and inverse problems. The continued investigation and development of these methods and their application in parameter identification has become a significant part of the program.

  11. Self field electromagnetism and quantum phenomena

    NASA Astrophysics Data System (ADS)

    Schatten, Kenneth H.

    1994-07-01

    Quantum Electrodynamics (QED) has been extremely successful inits predictive capability for atomic phenomena. Thus the greatest hope for any alternative view is solely to mimic the predictive capability of quantum mechanics (QM), and perhaps its usefulness will lie in gaining a better understanding of microscopic phenomena. Many ?paradoxes? and problematic situations emerge in QED. To combat the QED problems, the field of Stochastics Electrodynamics (SE) emerged, wherein a random ?zero point radiation? is assumed to fill all of space in an attmept to explain quantum phenomena, without some of the paradoxical concerns. SE, however, has greater failings. One is that the electromagnetic field energy must be infinit eto work. We have examined a deterministic side branch of SE, ?self field? electrodynamics, which may overcome the probelms of SE. Self field electrodynamics (SFE) utilizes the chaotic nature of electromagnetic emissions, as charges lose energy near atomic dimensions, to try to understand and mimic quantum phenomena. These fields and charges can ?interact with themselves? in a non-linear fashion, and may thereby explain many quantum phenomena from a semi-classical viewpoint. Referred to as self fields, they have gone by other names in the literature: ?evanesccent radiation?, ?virtual photons?, and ?vacuum fluctuations?. Using self fields, we discuss the uncertainty principles, the Casimir effects, and the black-body radiation spectrum, diffraction and interference effects, Schrodinger's equation, Planck's constant, and the nature of the electron and how they might be understood in the present framework. No new theory could ever replace QED. The self field view (if correct) would, at best, only serve to provide some understanding of the processes by which strange quantum phenomena occur at the atomic level. We discuss possible areas where experiments might be employed to test SFE, and areas where future work may lie.

  12. Cosmological magnetic fields from inflation in extended electromagnetism

    SciTech Connect

    Beltran Jimenez, Jose; Maroto, Antonio L.

    2011-01-15

    In this work we consider an extended electromagnetic theory in which the scalar state which is usually eliminated by means of the Lorenz condition is allowed to propagate. This state has been shown to generate a small cosmological constant in the context of standard inflationary cosmology. Here we show that the usual Lorenz gauge-breaking term now plays the role of an effective electromagnetic current. Such a current is generated during inflation from quantum fluctuations and gives rise to a stochastic effective charge density distribution. Because of the high electric conductivity of the cosmic plasma after inflation, the electric charge density generates currents which give rise to both vorticity and magnetic fields on sub-Hubble scales. Present upper limits on vorticity coming from temperature anisotropies of the CMB are translated into lower limits on the present value of cosmic magnetic fields. We find that, for a nearly scale invariant vorticity spectrum, magnetic fields B{sub {lambda}>}10{sup -12} G are typically generated with coherence lengths ranging from subgalactic scales up to the present Hubble radius. Those fields could act as seeds for a galactic dynamo or even account for observations just by collapse and differential rotation of the protogalactic cloud.

  13. Giant field enhancement in electromagnetic Helmholtz nanoantenna

    NASA Astrophysics Data System (ADS)

    Chevalier, Paul; Bouchon, Patrick; Greffet, Jean-Jacques; Pelouard, Jean-Luc; Haïdar, Riad; Pardo, Fabrice

    2014-11-01

    Inspired by the acoustic Helmholtz resonator, we propose a slit-box electromagnetic nanoantenna able to concentrate the energy of an incident beam into surfaces a thousand times smaller than with a classical lens. This design produces a giant electric field enhancement throughout the slit. The intensity enhancement reaches 104 in the visible range up to 108 in the THz range even with focused beams, thanks to an omnidirectional reception. These properties could target applications requiring extreme light concentration, such as surface-enhanced infrared absorption, nonlinear optics, and biophotonics.

  14. Transient electromagnetic fields near large earthing systems

    SciTech Connect

    Grcev, L.D.; Menter, F.E.

    1996-05-01

    Electromagnetic compatibility studies require knowledge of transient voltages that may be developed near earthing systems during lightning discharge, since such voltages may be coupled to sensitive electronic circuits. For such purpose accurate evaluation of transient electric field near to and/or at the surface of the grounding conductors is necessary. In this paper, a procedure for computation of transient fields near large earthing systems, as a response to a typical lightning current impulse, based on computational methodology developed in the field of antennas, is presented. Computed results are favorably compared with published measurement results. The model is applied to check the common assumption that the soil ionization can be neglected in case of large earthing systems. Presented results show that the soil ionization threshold is met and exceeded during typical lightning discharge in a large earthing system.

  15. Theory of a ring laser. [electromagnetic field and wave equations

    NASA Technical Reports Server (NTRS)

    Menegozzi, L. N.; Lamb, W. E., Jr.

    1973-01-01

    Development of a systematic formulation of the theory of a ring laser which is based on first principles and uses a well-known model for laser operation. A simple physical derivation of the electromagnetic field equations for a noninertial reference frame in uniform rotation is presented, and an attempt is made to clarify the nature of the Fox-Li modes for an open polygonal resonator. The polarization of the active medium is obtained by using a Fourier-series method which permits the formulation of a strong-signal theory, and solutions are given in terms of continued fractions. It is shown that when such a continued fraction is expanded to third order in the fields, the familiar small-signal ring-laser theory is obtained.

  16. Near-field radiofrequency electromagnetic exposure assessment.

    PubMed

    Rubtsova, Nina; Perov, Sergey; Belaya, Olga; Kuster, Niels; Balzano, Quirino

    2015-09-01

    Personal wireless telecommunication devices, such as radiofrequency (RF) electromagnetic field (EMF) sources operated in vicinity of human body, have possible adverse health effects. Therefore, the correct EMF assessment is necessary in their near field. According to international near-field measurement criteria, the specific absorption rate (SAR) is used for absorbed energy distribution assessment in tissue simulating liquid phantoms. The aim of this investigation is to validate the relationship between the H-field of incident EMF and absorbed energy in phantoms. Three typical wireless telecommunication system frequencies are considered (900, 1800 and 2450 MHz). The EMF source at each frequency is an appropriate half-wave dipole antenna and the absorbing medium is a flat phantom filled with the suitable tissue simulating liquid. Two methods for SAR estimation have been used: standard procedure based on E-field measured in tissue simulating medium and a proposed evaluation by measuring the incident H-field. Compared SAR estimations were performed for various distances between sources and phantom. Also, these research data were compared with simulation results, obtained by using finite-difference time-domain method. The acquired data help to determine the source near-field space characterized by the smallest deviation between SAR estimation methods. So, this region near the RF source is suitable for correct RF energy absorption assessment using the magnetic component of the RF fields.

  17. Electromagnetic fields with vanishing scalar invariants

    NASA Astrophysics Data System (ADS)

    Ortaggio, Marcello; Pravda, Vojtěch

    2016-06-01

    We determine the class of p-forms {\\boldsymbol{F}} that possess vanishing scalar invariants (VSIs) at arbitrary order in an n-dimensional spacetime. Namely, we prove that {\\boldsymbol{F}} is a VSI if and only if if it is of type N, its multiple null direction {\\boldsymbol{\\ell }} is ‘degenerate Kundt’, and {\\pounds }{\\boldsymbol{\\ell }}{\\boldsymbol{F}}=0. The result is theory-independent. Next, we discuss the special case of Maxwell fields, both at the level of test fields and of the full Einstein-Maxwell equations. These describe electromagnetic non-expanding waves propagating in various Kundt spacetimes. We further point out that a subset of these solutions possesses a universal property, i.e. they also solve (virtually) any generalized (non-linear and with higher derivatives) electrodynamics, possibly also coupled to Einstein’s gravity.

  18. Evaluation of uncertainty in the measurement of environmental electromagnetic fields.

    PubMed

    Vulević, B; Osmokrović, P

    2010-09-01

    With regard to Non-ionising radiation protection, the relationship between human exposure to electromagnetic fields and health is controversial. Electromagnetic fields have become omnipresent in the daily environment. This paper assesses the problem of how to compare a measurement result with a limit fixed by the standard for human exposure to electric, magnetic and electromagnetic fields (0 Hz-300 GHz). The purpose of the paper is an appropriate representation of the basic information about evaluation of measurement uncertainty.

  19. Rotating field mass and velocity analyzer

    NASA Technical Reports Server (NTRS)

    Smith, Steven Joel (Inventor); Chutjian, Ara (Inventor)

    1998-01-01

    A rotating field mass and velocity analyzer having a cell with four walls, time dependent RF potentials that are applied to each wall, and a detector. The time dependent RF potentials create an RF field in the cell which effectively rotates within the cell. An ion beam is accelerated into the cell and the rotating RF field disperses the incident ion beam according to the mass-to-charge (m/e) ratio and velocity distribution present in the ion beam. The ions of the beam either collide with the ion detector or deflect away from the ion detector, depending on the m/e, RF amplitude, and RF frequency. The detector counts the incident ions to determine the m/e and velocity distribution in the ion beam.

  20. Pumping of water through carbon nanotubes by rotating electric field and rotating magnetic field

    NASA Astrophysics Data System (ADS)

    Li, Xiao-Peng; Kong, Gao-Pan; Zhang, Xing; He, Guo-Wei

    2013-09-01

    Using molecular dynamics simulations, we demonstrate pumping of water through a carbon nanotube by applying the combination of a rotating electric field and a rotating magnetic field. The driving force is a Lorentz force generated from the motion of charges in the magnetic field, and the motion is caused by the rotation of the electric field. We find that there exits a linear relationship between the average pumping velocity v and magnetic field strength B, which can be used to control the flux of the continuous unidirectional water flow. This approach is expected to be used in liquid circulation without a pressure gradient.

  1. Note on Inverse Bremsstrahlung in a Strong Electromagnetic Field

    DOE R&D Accomplishments Database

    Bethe, H. A.

    1972-09-01

    The collisional energy loss of an electron undergoing forced oscillation in an electromagnetic field behaves quite differently in the low and high intensity limits. ... It is shown that in the case of an electromagnetic field v {sub o} >> v {sub t} the rate of transfer is much slower, and actually decreases with the strength of the field.

  2. Plant Responses to High Frequency Electromagnetic Fields

    PubMed Central

    Vian, Alain; Davies, Eric; Gendraud, Michel; Bonnet, Pierre

    2016-01-01

    High frequency nonionizing electromagnetic fields (HF-EMF) that are increasingly present in the environment constitute a genuine environmental stimulus able to evoke specific responses in plants that share many similarities with those observed after a stressful treatment. Plants constitute an outstanding model to study such interactions since their architecture (high surface area to volume ratio) optimizes their interaction with the environment. In the present review, after identifying the main exposure devices (transverse and gigahertz electromagnetic cells, wave guide, and mode stirred reverberating chamber) and general physics laws that govern EMF interactions with plants, we illustrate some of the observed responses after exposure to HF-EMF at the cellular, molecular, and whole plant scale. Indeed, numerous metabolic activities (reactive oxygen species metabolism, α- and β-amylase, Krebs cycle, pentose phosphate pathway, chlorophyll content, terpene emission, etc.) are modified, gene expression altered (calmodulin, calcium-dependent protein kinase, and proteinase inhibitor), and growth reduced (stem elongation and dry weight) after low power (i.e., nonthermal) HF-EMF exposure. These changes occur not only in the tissues directly exposed but also systemically in distant tissues. While the long-term impact of these metabolic changes remains largely unknown, we propose to consider nonionizing HF-EMF radiation as a noninjurious, genuine environmental factor that readily evokes changes in plant metabolism. PMID:26981524

  3. EVALUATION OF A SUPERCONDUCTING ROTATING ELECTRIC GENERATOR.

    DTIC Science & Technology

    ELECTRIC POWER, *PRODUCTION, GENERATORS , SUPERCONDUCTORS, SUPERCONDUCTORS, ROTATION, FEASIBILITY STUDIES, REFRIGERATION SYSTEMS, MAGNETIC FIELDS, TEST EQUIPMENT, ELECTRONIC EQUIPMENT, SOLENOIDS, TEMPERATURE, ELECTROMAGNETS.

  4. Visualizing electromagnetic fields in metals by MRI

    NASA Astrophysics Data System (ADS)

    Chandrashekar, Chandrika Sefcikova; Shellikeri, Annadanesh; Chandrashekar, S.; Taylor, Erika A.; Taylor, Deanne M.

    2017-02-01

    Based upon Maxwell's equations, it has long been established that oscillating electromagnetic (EM) fields incident upon a metal surface, decay exponentially inside the conductor, leading to a virtual absence of EM fields at sufficient depths. Magnetic resonance imaging (MRI) utilizes radiofrequency (r.f.) EM fields to produce images. Here we present a visualization of a virtual EM vacuum inside a bulk metal strip by MRI, amongst several findings. At its simplest, an MRI image is an intensity map of density variations across voxels (pixels) of identical size (=Δ x Δ y Δ z ). By contrast in bulk metal MRI, we uncover that despite uniform density, intensity variations arise from differing effective elemental volumes (voxels) from different parts of the bulk metal. Further, we furnish chemical shift imaging (CSI) results that discriminate different faces (surfaces) of a metal block according to their distinct nuclear magnetic resonance (NMR) chemical shifts, which holds much promise for monitoring surface chemical reactions noninvasively. Bulk metals are ubiquitous, and MRI is a premier noninvasive diagnostic tool. Combining the two, the emerging field of bulk metal MRI can be expected to grow in importance. The findings here may impact further development of bulk metal MRI and CSI.

  5. Rotational and magnetic field instabilities in neutron stars

    SciTech Connect

    Kokkotas, Kostas D.

    2014-01-14

    In this short review we present recent results on the dynamics of neutron stars and their magnetic fields. We discuss the progress that has been made, during the last 5 years, in understanding the rotational instabilities with emphasis to the one due to the f-mode, the possibility of using gravitational wave detection in constraining the parameters of neutron stars and revealing the equation of state as well as the detectability of gravitational waves produced during the unstable phase of a neutron star’s life. In addition we discuss the dynamics of extremely strong magnetic fields observed in a class of neutron stars (magnetars). Magnetic fields of that strength are responsible for highly energetic phenomena (giant flares) and we demonstrate that the analysis of the emitted electromagnetic radiation can lead in constraining the parameters of neutron stars. Furthermore, we present our results from the study of such violent phenomena in association with the emission of gravitational radiation.

  6. Inelastic deformation of conductive bodies in electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Altenbach, Holm; Morachkovsky, Oleg; Naumenko, Konstantin; Lavinsky, Denis

    2016-09-01

    Inelastic deformation of conductive bodies under the action of electromagnetic fields is analyzed. Governing equations for non-stationary electromagnetic field propagation and elastic-plastic deformation are presented. The variational principle of minimum of the total energy is applied to formulate the numerical solution procedure by the finite element method. With the proposed method, distributions of vector characteristics of the electromagnetic field and tensor characteristics of the deformation process are illustrated for the inductor-workpiece system within a realistic electromagnetic forming process.

  7. Mortality in workers exposed to electromagnetic fields

    SciTech Connect

    Milham, S. Jr.

    1985-10-01

    In an occupational mortality analysis of 486,000 adult male death records filed in Washington State in the years 1950-1982, leukemia and the non-Hodgkin's lymphomas show increased proportionate mortality ratios (PMRs) in workers employed in occupations with intuitive exposures to electromagnetic fields. Nine occupations of 219 were considered to have electric or magnetic field exposures. These were: electrical and electronic technicians, radio and telegraph operators, radio and television repairmen, telephone and power linemen, power station operators, welders, aluminum reduction workers, motion picture projectionists and electricians. There were 12,714 total deaths in these occupations. Eight of the nine occupations had PMR increases for leukemia (International Classification of Diseases (ICD), seventh revision 204) and seven of the nine occupations had PMR increases for the other lymphoma category (7th ICD 200.2, 202). The highest PMRs were seen for acute leukemia: (67 deaths observed, 41 deaths expected; PMR 162), and in the other lymphomas (51 deaths observed, 31 deaths expected; PMR 164). No increase in mortality was seen for Hodgkin's disease or multiple myeloma. These findings offer some support for the hypothesis that electric and magnetic fields may be carcinogenic.

  8. Electromagnetically induced transparency in modulated laser fields

    NASA Astrophysics Data System (ADS)

    Jiao, Yuechun; Yang, Zhiwei; Zhang, Hao; Zhang, Linjie; Raithel, Georg; Zhao, Jianming; Jia, Suotang

    2017-02-01

    We study electromagnetically induced transparency (EIT) in a room-temperature cesium vapor cell using wavelength-modulated probe laser light. In the utilized cascade level scheme, the probe laser drives the lower transition 6S {}1/2(F = 4) → 6P {}3/2 (F’ = 5), while the coupling laser drives the Rydberg transition 6P {}3/2 → 57S {}1/2. The probe laser has a fixed average frequency and is modulated at a frequency of a few kHz, with a variable modulation amplitude in the range of tens of MHz. The probe transmission is measured as a function of the detuning of the coupling laser from the Rydberg resonance. The first-harmonic demodulated EIT signal has two peaks that are, in the case of large modulation amplitude, separated by the peak-to-peak modulation amplitude of the probe laser times a scaling factor {λ }{{p}}/{λ }{{c}}, where {λ }{{p}} and {λ }{{c}} are the probe- and coupling-laser wavelengths. The scaling factor is due to Doppler shifts in the EIT geometry. Second-harmonic demodulated EIT signals, obtained with small modulation amplitudes, yield spectral lines that are much narrower than corresponding lines in the modulation-free EIT spectra. The resultant spectroscopic resolution enhancement is conducive to improved measurements of radio-frequency (RF) fields based on Rydberg-atom EIT, an approach in which the response of Rydberg atoms to RF fields is exploited to characterize RF fields. Here, we employ wavelength modulation spectroscopy to reduce the uncertainty of atom-based frequency and field measurement of an RF field in the VHF radio band.

  9. Sensing network for electromagnetic fields generated by seismic activities

    NASA Astrophysics Data System (ADS)

    Gershenzon, Naum I.; Bambakidis, Gust; Ternovskiy, Igor V.

    2014-06-01

    The sensors network is becoming prolific and play now increasingly more important role in acquiring and processing information. Cyber-Physical Systems are focusing on investigation of integrated systems that includes sensing, networking, and computations. The physics of the seismic measurement and electromagnetic field measurement requires special consideration how to design electromagnetic field measurement networks for both research and detection earthquakes and explosions along with the seismic measurement networks. In addition, the electromagnetic sensor network itself could be designed and deployed, as a research tool with great deal of flexibility, the placement of the measuring nodes must be design based on systematic analysis of the seismic-electromagnetic interaction. In this article, we review the observations of the co-seismic electromagnetic field generated by earthquakes and man-made sources such as vibrations and explosions. The theoretical investigation allows the distribution of sensor nodes to be optimized and could be used to support existing geological networks. The placement of sensor nodes have to be determined based on physics of electromagnetic field distribution above the ground level. The results of theoretical investigations of seismo-electromagnetic phenomena are considered in Section I. First, we compare the relative contribution of various types of mechano-electromagnetic mechanisms and then analyze in detail the calculation of electromagnetic fields generated by piezomagnetic and electrokinetic effects.

  10. Assessment of Electromagnetic Fields at NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Ficklen, Carter B.

    1995-01-01

    This report presents the results of an assessment of ElectroMagnetic Fields (EMF) completed at NASA Langley Research Center as part of the Langley Aerospace Research Summer Scholars Program. This project was performed to determine levels of electromagnetic fields, determine the significance of the levels present, and determine a plan to reduce electromagnetic field exposure, if necessary. This report also describes the properties of electromagnetic fields and their interaction with humans. The results of three major occupational epidemiological studies is presented to determine risks posed to humans by EMF exposure. The data for this report came from peer-reviewed journal articles and government publications pertaining to the health effects of electromagnetic fields.

  11. Fluxes of electromagnetic field energy in HTSC transformers

    NASA Astrophysics Data System (ADS)

    Volkov, E. P.; Dzhafarov, E. A.

    2016-12-01

    The transfer of electric power in an HTSC electromagnetic system is considered using the Poynting vector. An analysis of the process of transfer of electromagnetic field energy in HTSC transformers with and without an iron core is given. It is shown that the power of an HTSC transformer increases when its magnetic core is made from amorphous electrical steel. Schemes of HTSC transformers with a localized magnetic field are given with cylindrical and disk symmetrical interleaved windings providing the cost-saving process of transfer of large electromagnetic energy at a high degree of its uniformity and improve the factor of nonuniformity of electromagnetic flux density.

  12. Electromagnetic Fields, Oxidative Stress, and Neurodegeneration

    PubMed Central

    Consales, Claudia; Merla, Caterina; Marino, Carmela; Benassi, Barbara

    2012-01-01

    Electromagnetic fields (EMFs) originating both from both natural and manmade sources permeate our environment. As people are continuously exposed to EMFs in everyday life, it is a matter of great debate whether they can be harmful to human health. On the basis of two decades of epidemiological studies, an increased risk for childhood leukemia associated with Extremely Low Frequency fields has been consistently assessed, inducing the International Agency for Research on Cancer to insert them in the 2B section of carcinogens in 2001. EMFs interaction with biological systems may cause oxidative stress under certain circumstances. Since free radicals are essential for brain physiological processes and pathological degeneration, research focusing on the possible influence of the EMFs-driven oxidative stress is still in progress, especially in the light of recent studies suggesting that EMFs may contribute to the etiology of neurodegenerative disorders. This review synthesizes the emerging evidences about this topic, highlighting the wide data uncertainty that still characterizes the EMFs effect on oxidative stress modulation, as both pro-oxidant and neuroprotective effects have been documented. Care should be taken to avoid methodological limitations and to determine the patho-physiological relevance of any alteration found in EMFs-exposed biological system. PMID:22991514

  13. Geometric Phase Of The Faraday Rotation Of Electromagnetic Waves In Magnetized Plasma

    SciTech Connect

    Jian Liu and Hong Qin

    2011-11-07

    The geometric phase of circularly polarized electromagnetic waves in nonuniform magnetized plasmas is studied theoretically. The variation of the propagation direction of circularly polarized waves results in a geometric phase, which also contributes to the Faraday rotation, in addition to the standard dynamical phase. The origin and properties of the geometric phase is investigated. The in uence of the geometric phase to plasma diagnostics using Faraday rotation is also discussed as an application of the theory.

  14. Effects of phase conjugation on electromagnetic optical fields propagating in free space

    NASA Astrophysics Data System (ADS)

    Kanseri, Bhaskar

    2017-03-01

    By using the property of phase conjugation, we demonstrate that the inverse of van Cittert–Zernike theorem holds for electromagnetic (EM) fields propagating in free space. This essentially implies that spatially incoherent partially polarized field distributions can be generated from spatially coherent partially polarized optical fields. We further utilize phase conjugation with a polarization rotator to swap the spatial coherence properties of orthogonal polarization components of EM fields on propagation, at least in free space. This study suggests that the method of phase conjugation could be potentially useful in arbitrarily manipulating spatial coherence properties of vector optical fields in the field plane.

  15. Feedback-Driven Mode Rotation Control by Electro-Magnetic Torque

    NASA Astrophysics Data System (ADS)

    Okabayashi, M.; Strait, E. J.; Garofalo, A. M.; La Haye, R. J.; in, Y.; Hanson, J. M.; Shiraki, D.; Volpe, F.

    2013-10-01

    The recent experimental discovery of feedback-driven mode rotation control, supported by modeling, opens new approaches for avoidance of locked tearing modes that otherwise lead to disruptions. This approach is an application of electro-magnetic (EM) torque using 3D fields, routinely maximized through a simple feedback system. In DIII-D, it is observed that a feedback-applied radial field can be synchronized in phase with the poloidal field component of a large amplitude tearing mode, producing the maximum EM torque input. The mode frequency can be maintained in the 10 Hz to 100 Hz range in a well controlled manner, sustaining the discharges. Presently, in the ITER internal coils designed for edge localized mode (ELM) control can only be varied at few Hz, yet, well below the inverse wall time constant. Hence, ELM control system could in principle be used for this feedback-driven mode control in various ways. For instance, the locking of MHD modes can be avoided during the controlled shut down of multi hundreds Mega Joule EM stored energy in case of emergency. Feedback could also be useful to minimize mechanical resonances at the disruption events by forcing the MHD frequency away from dangerous ranges. Work supported by the US DOE under DE-AC02-09CH11466, DE-FC-02-04ER54698, DE-FG02-08ER85195, and DE-FG02-04ER54761.

  16. Motional sideband excitation using rotating electric fields

    NASA Astrophysics Data System (ADS)

    Isaac, C. A.

    2013-04-01

    A form of motional sideband excitation is described in which a rotating dipole electric field is applied asymmetrically onto a Penning-type trap in the presence of a mechanism for cooling the axial motion of the trapped particles. In contrast to the traditional motional sideband excitation, which uses an oscillating electric field, the rotating field results in only one active sideband in each sense of rotation and so avoids accidental excitation of the other sideband making it applicable to Penning-type traps with a large degree of anharmonicity. Expressions are derived for the magnetron radius expansion and compression rates attainable, and approximations are made for the case of strong and weak drives. A comparison is made with data, taken using a two-stage positron accumulator presented by Isaac [C. A. Isaac, C. J. Baker, T. Mortensen, D. P. van der Werf, and M. Charlton, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.107.033201 107, 033201 (2011)], showing good agreement between the model and experiment.

  17. Growth stimulation of biological cells and tissue by electromagnetic fields and uses thereof

    NASA Technical Reports Server (NTRS)

    Wolf, David A. (Inventor); Goodwin, Thomas J. (Inventor)

    2004-01-01

    The present invention provides systems for growing two or three dimensional mammalian cells within a culture medium facilitated by an electromagnetic field, and preferably, a time varying electromagnetic field. The cells and culture medium are contained within a fixed or rotating culture vessel, and the electromagnetic field is emitted from at least one electrode. In one embodiment, the electrode is spaced from the vessel. The invention further provides methods to promote neural tissue regeneration by means of culturing the neural cells in the claimed system. In one embodiment, neuronal cells are grown within longitudinally extending tissue strands extending axially along and within electrodes comprising electrically conductive channels or guides through which a time varying electrical current is conducted, the conductive channels being positioned within a culture medium.

  18. Growth Stimulation of Biological Cells and Tissue by Electromagnetic Fields and Uses Thereof

    NASA Technical Reports Server (NTRS)

    Wolf, David A. (Inventor); Goodwin, Thomas J. (Inventor)

    2002-01-01

    The present invention provides systems for growing two or three dimensional mammalian cells within a culture medium facilitated by an electromagnetic field, and preferably, a time varying electromagnetic field. The cells, and culture medium are contained within a fixed or rotating culture vessel, and the electromagnetic field is emitted from at least one electrode. In one embodiment, the electrode is spaced from the vessel. The invention further provides methods to promote neural tissue regeneration by means of culturing the neural cells in the claimed system. In one embodiment, neuronal cells are grown within longitudinally extending tissue strands extending axially along and within electrodes comprising electrically conductive channels or guides through which a time varying electrical current is conducted, the conductive channels being positioned within a culture medium.

  19. Interpreting marine controlled source electromagnetic field behaviour with streamlines

    NASA Astrophysics Data System (ADS)

    Pethick, A. M.; Harris, B. D.

    2013-10-01

    Streamlines represent particle motion within a vector field as a single line structure and have been used in many areas of geophysics. We extend the concept of streamlines to interactive three dimensional representations of the coupled vector fields generated during marine controlled source electromagnetic surveys. These vector fields have measurable amplitudes throughout many hundreds of cubic kilometres. Electromagnetic streamline representation makes electromagnetic interactions within complex geo-electrical setting comprehensible. We develop an interface to rapidly compute and interactively visualise the electric and magnetic fields as streamlines for 3D marine controlled source electromagnetic surveys. Several examples highlighting how interactive use has value in marine controlled source electromagnetic survey design, interpretation and teaching are provided. The first videos of electric, magnetic and Poynting vector field streamlines are provided along with the first published example of the airwave represented as streamlines. We demonstrate that the electric field airwave is a circulating vortex moving down and out from the air-water interface towards the ocean floor. The use of interactive streamlines is not limited to marine controlled source electromagnetic methods. Streamlines provides a high level visualisation tool for interpreting the electric and magnetic field behaviour generated by a wide range of electromagnetic survey configurations for complex 3D geo-electrical settings.

  20. [Dynamics of biomacromolecules in coherent electromagnetic radiation field].

    PubMed

    Leshcheniuk, N S; Apanasevich, E E; Tereshenkov, V I

    2014-01-01

    It is shown that induced oscillations and periodic displacements of the equilibrium positions occur in biomacromolecules in the absence of electromagnetic radiation absorption, due to modulation of interaction potential between atoms and groups of atoms forming the non-valence bonds in macromolecules by the external electromagnetic field. Such "hyperoscillation" state causes inevitably the changes in biochemical properties of macromolecules and conformational transformation times.

  1. The van Cittert-Zernike theorem for electromagnetic fields.

    PubMed

    Ostrovsky, Andrey S; Martínez-Niconoff, Gabriel; Martínez-Vara, Patricia; Olvera-Santamaría, Miguel A

    2009-02-02

    The van Cittert-Zernike theorem, well known for the scalar optical fields, is generalized for the case of vector electromagnetic fields. The deduced theorem shows that the degree of coherence of the electromagnetic field produced by the completely incoherent vector source increases on propagation whereas the degree of polarization remains unchanged. The possible application of the deduced theorem is illustrated by an example of optical simulation of partially coherent and partially polarized secondary source with the controlled statistical properties.

  2. Electromagnetic harvester for lateral vibration in rotating machines

    NASA Astrophysics Data System (ADS)

    de Araujo, Marcus Vinícius Vitoratti; Nicoletti, Rodrigo

    2015-02-01

    Energy harvesters are devices that convert mechanical energy, usually vibration, into electrical energy that can be used to supply low power circuits (e.g. sensors). In this work, an energy harvester is designed for converting the mechanical energy of the lateral vibrations of shafts into electrical energy. For that, permanent magnets are mounted in the shaft and coils are mounted in a fixed structure. A configuration analysis is performed to find the appropriated polarization of the magnets and orientation of the coils in order to have electromagnetic induction without resisting torque on the shaft. Experimental tests are done for different electrical configurations of the coils: independent, in series and, in parallel. The results show that more electric power is induced when the coils are connected in series, and vibration reduction is more evident when the coils are connected independently.

  3. Algebraic structure of general electromagnetic fields and energy flow

    SciTech Connect

    Hacyan, Shahen

    2011-08-15

    Highlights: > Algebraic structure of general electromagnetic fields in stationary spacetime. > Eigenvalues and eigenvectors of the electomagnetic field tensor. > Energy-momentum in terms of eigenvectors and Killing vector. > Explicit form of reference frame with vanishing Poynting vector. > Application of formalism to Bessel beams. - Abstract: The algebraic structures of a general electromagnetic field and its energy-momentum tensor in a stationary space-time are analyzed. The explicit form of the reference frame in which the energy of the field appears at rest is obtained in terms of the eigenvectors of the electromagnetic tensor and the existing Killing vector. The case of a stationary electromagnetic field is also studied and a comparison is made with the standard short-wave approximation. The results can be applied to the general case of a structured light beams, in flat or curved spaces. Bessel beams are worked out as example.

  4. Tailoring the Electromagnetic Near Field with Patterned Surfaces: Near-Field Plates

    DTIC Science & Technology

    2014-12-10

    AFRL-OSR-VA-TR-2014-0355 PECASE)TAILORING THE ELECTROMAGNETIC NEAR FIELD WITH PATTERNED SURFACES - NEAR- Anthony Grbic UNIVERSITY OF MICHIGAN Final...298 (Re . 8-98) v Prescribed by ANSI Std. Z39.18 Tailoring the Electromagnetic Near Field with Patterned Surfaces: Near-Field Plates Final Report...Unidirectional Near-Field Plates 11 8. Near-Field Plates for Wireless Non-Radiative Power Transfer 11 C. Impact 12 III. Controlling Electromagnetic

  5. Tools and setups for experiments with AC and rotating magnetic fields

    NASA Astrophysics Data System (ADS)

    Ponikvar, D.

    2010-09-01

    A rotating magnetic field is the basis for the transformation of electrical energy to mechanical energy. School experiments on the rotating magnetic field are rare since they require the use of specially prepared mechanical setups and/or relatively large, three-phase power supplies to achieve strong magnetic fields. This paper proposes several experiments and describes setups and tools which are easy to obtain and work with. Free software is offered to generate the required signals by a personal computer. The experiments can be implemented in introductory physics courses on electromagnetism for undergraduates or specialized courses at high schools.

  6. [Computational radiofrequency electromagnetic field dosimetry in evaluation of biological effects].

    PubMed

    Perov, S Iu; Kudryashov, Iu B; Rubtsova, N B

    2012-01-01

    Given growing computational resources, radiofrequency electromagnetic field dosimetry is becoming more vital in the study of biological effects of non-ionizing electromagnetic radiation. The study analyzes numerical methods which are used in theoretical dosimetry to assess the exposure level and specific absorption rate distribution. The advances of theoretical dosimetry are shown. Advantages and disadvantages of different methods are analyzed in respect to electromagnetic field biological effects. The finite-difference time-domain method was implemented in detail; also evaluated were possible uncertainties of complex biological structure simulation for bioelectromagnetic investigations.

  7. Effects of Electromagnetic Fields on Fish and Invertebrates

    SciTech Connect

    Schultz, Irvin R.; Woodruff, Dana L.; Marshall, Kathryn E.; Pratt, William J.; Roesijadi, Guritno

    2010-10-13

    In this progress report, we describe the preliminary experiments conducted with three fish and one invertebrate species to determine the effects of exposure to electromagnetic fields. During fiscal year 2010, experiments were conducted with coho salmon (Onchrohychus kisutch), California halibut (Paralicthys californicus), Atlantic halibut (Hippoglossus hippoglossus), and Dungeness crab (Cancer magister). The work described supports Task 2.1.3: Effects on Aquatic Organisms, Subtask 2.1.3.1: Electromagnetic Fields.

  8. Electromagnetic fields and potentials generated by massless charged particles

    SciTech Connect

    Azzurli, Francesco; Lechner, Kurt

    2014-10-15

    We provide for the first time the exact solution of Maxwell’s equations for a massless charged particle moving on a generic trajectory at the speed of light. In particular we furnish explicit expressions for the vector potential and the electromagnetic field, which were both previously unknown, finding that they entail different physical features for bounded and unbounded trajectories. With respect to the standard Liénard–Wiechert field the electromagnetic field acquires singular δ-like contributions whose support and dimensionality depend crucially on whether the motion is (a) linear, (b) accelerated unbounded, (c) accelerated bounded. In the first two cases the particle generates a planar shock-wave-like electromagnetic field traveling along a straight line. In the second and third cases the field acquires, in addition, a δ-like contribution supported on a physical singularity-string attached to the particle. For generic accelerated motions a genuine radiation field is also present, represented by a regular principal-part type distribution diverging on the same singularity-string. - Highlights: • First exact solution of Maxwell’s equations for massless charges in arbitrary motion. • Explicit expressions of electromagnetic fields and potentials. • Derivations are rigorous and based on distribution theory. • The form of the field depends heavily on whether the motion is bounded or unbounded. • The electromagnetic field contains unexpected Dirac-delta-function contributions.

  9. Biological effects of prolonged exposure to ELF electromagnetic fields in rats: III. 50 Hz electromagnetic fields.

    PubMed

    Zecca, L; Mantegazza, C; Margonato, V; Cerretelli, P; Caniatti, M; Piva, F; Dondi, D; Hagino, N

    1998-01-01

    Groups of adult male Sprague Dawley rats (64 rats each) were exposed for 8 months to electromagnetic fields (EMF) of two different field strength combinations: 5microT - 1kV/m and 100microT - 5kV/m. A third group was sham exposed. Field exposure was 8 hrs/day for 5 days/week. Blood samples were collected for hematology determinations before the onset of exposure and at 12 week intervals. At sacrifice, liver, heart, mesenteric lymph nodes, bone marrow, and testes were collected for morphology and histology assessments, while the pineal gland and brain were collected for biochemical determinations. At both field strength combinations, no pathological changes were observed in animal growth rate, in morphology and histology of the collected tissue specimens (liver, heart, mesenteric lymph nodes, testes, bone marrow), and in serum chemistry. An increase in norepinephrine levels occurred in the pineal gland of rats exposed to the higher field strength. The major changes in the brain involved the opioid system in frontal cortex, parietal cortex, and hippocampus. From the present findings it may be hypothesized that EMF may cause alteration of some brain functions.

  10. Rotational Doppler shift for electromagnetic waves carrying orbital angular momentum based on spectrum analysis

    NASA Astrophysics Data System (ADS)

    Yang, Tao; Wang, Gang

    2017-03-01

    We investigate the rotational Doppler effect for the electromagnetic wave carrying orbital angular momentum (OAM) with a method based on spectrum analysis, which is appropriate for both optics and free-space radio cases. We find that the frequency spectrum received is the convolution of emission spectrum and a discrete spectrum about OAM states, and verify it in the numerical simulations as well. This discovery makes it possible to distinguish the linear and rotational Doppler shift, and is helpful to developments of remote sensing and velocimetry in radar.

  11. [The influence of electromagnetic fields on flora and fauna].

    PubMed

    Rochalska, Małgorzata

    2009-01-01

    This paper presents the influence of natural and artificial electromagnetic fields (EMF) on fauna and flora. The mechanisms of Earth's magnetic field detection and the use of this skill by migratory animals to faultlessly reach the destination of their travel are discussed, as well as the positive effects of electric and magnetic fields on plants relative to their physiology, yielding and health. EMF influence on social insects and animal organisms, including possible DNA damages and DNA repair systems, is presented. The influence of high frequency electromagnetic fields on birds nesting is also discussed.

  12. MESA: a new configuration for measuring electromagnetic field fluctuations.

    PubMed

    Harte, T M; Black, D L; Hollinshead, M T

    1999-11-01

    This paper describes how the multi-energy sensor array has been refitted to meet the needs of measuring geomagnetic and other types of electromagnetic phenomena in an environment. This portable laptop computer system was designed to measure the interaction of multiple frequencies with the psychological and physiological processes that underlie human exposure to electromagnetic fields across the spectra. New sensors and analytical software have been implemented in the new configuration.

  13. Electropumping of water with rotating electric fields.

    PubMed

    De Luca, Sergio; Todd, B D; Hansen, J S; Daivis, Peter J

    2013-04-21

    Pumping of fluids confined to nanometer dimension spaces is a technically challenging yet vitally important technological application with far reaching consequences for lab-on-a-chip devices, biomimetic nanoscale reactors, nanoscale filtration devices and the like. All current pumping mechanisms require some sort of direct intrusion into the nanofluidic system, and involve mechanical or electronic components. In this paper, we present the first nonequilibrium molecular dynamics results to demonstrate that non-intrusive electropumping of liquid water on the nanoscale can be performed by subtly exploiting the coupling of spin angular momentum to linear streaming momentum. A spatially uniform rotating electric field is applied to water molecules, which couples to their permanent electric dipole moments. The resulting molecular rotational momentum is converted into linear streaming momentum of the fluid. By selectively tuning the degree of hydrophobicity of the solid walls one can generate a net unidirectional flow. Our results for the linear streaming and angular velocities of the confined water are in general agreement with the extended hydrodynamical theory for this process, though also suggest refinements to the theory are required. These numerical experiments confirm that this new concept for pumping of polar nanofluids can be employed under laboratory conditions, opening up significant new technological possibilities.

  14. Electropumping of water with rotating electric fields

    NASA Astrophysics Data System (ADS)

    De Luca, Sergio; Todd, B. D.; Hansen, J. S.; Daivis, Peter J.

    2013-04-01

    Pumping of fluids confined to nanometer dimension spaces is a technically challenging yet vitally important technological application with far reaching consequences for lab-on-a-chip devices, biomimetic nanoscale reactors, nanoscale filtration devices and the like. All current pumping mechanisms require some sort of direct intrusion into the nanofluidic system, and involve mechanical or electronic components. In this paper, we present the first nonequilibrium molecular dynamics results to demonstrate that non-intrusive electropumping of liquid water on the nanoscale can be performed by subtly exploiting the coupling of spin angular momentum to linear streaming momentum. A spatially uniform rotating electric field is applied to water molecules, which couples to their permanent electric dipole moments. The resulting molecular rotational momentum is converted into linear streaming momentum of the fluid. By selectively tuning the degree of hydrophobicity of the solid walls one can generate a net unidirectional flow. Our results for the linear streaming and angular velocities of the confined water are in general agreement with the extended hydrodynamical theory for this process, though also suggest refinements to the theory are required. These numerical experiments confirm that this new concept for pumping of polar nanofluids can be employed under laboratory conditions, opening up significant new technological possibilities.

  15. Electromagnetic field effects on binary dimethylimidazolium-based ionic liquid/water solutions.

    PubMed

    English, Niall J; Mooney, Damian A

    2009-11-07

    The non-thermal effects of electromagnetic fields in the microwave to far-infrared frequency on neat dimethylimidazolium chloride and triflate salts and their binary mixtures with water have been investigated by means of non-equilibrium molecular dynamics simulation. Significant alterations in dipole alignment and molecular mobility were found vis-à-vis zero-field conditions for mixtures of varying composition. Results indicate that the dimethylimidazolium and triflate ions respond most significantly to frequencies much lower than that of water in terms of dipole alignment and molecular mobility, and this was rationalized. in terms of dipole moment magnitudes, rotational inertia and translational field response.

  16. Suppression and control of leakage field in electromagnetic helical microwiggler

    SciTech Connect

    Ohigashi, N.; Tsunawaki, Y.; Imasaki, K.

    1995-12-31

    Shortening the period of electromagnetic wiggler introduces both the radical increase of the leakage field and the decrease of the field in the gap region. The leakage field is severer problem in planar electromagnetic wiggler than in helical wiggler. Hence, in order to develop a short period electromagnetic wiggler, we have adopted {open_quotes}three poles per period{close_quotes} type electromagnetic helical microwiggler. In this work, we inserted the permanent magnet (PM) blocks with specific magnetized directions in the space between magnetic poles, for suppressing the leakage field flowing out from a pole face to the neighboring pole face. These PM-blocks must have higher intrinsic coersive force than saturation field of pole material. The gap field due to each pole is adjustable by controlling the leakage fields, that is, controlling the position of each iron screw set in each retainer fixing the PM-blocks. At present time, a test wiggler with period 7.8mm, periodical number 10 and gap length 4.6mm has been manufactured. Because the ratio of PM-block aperture to gap length is important parameter to suppress the leakage field, the parameter has been surveyed experimentally for PM-blocks with several dimensions of aperture. The field strength of 3-5kG (K=0.2-0.4) would be expected in the wiggler.

  17. Electromagnetic homeostasis and the role of low-amplitude electromagnetic fields on life organization.

    PubMed

    De Ninno, Antonella; Pregnolato, Massimo

    2017-01-01

    The appearance of endogenous electromagnetic fields in biological systems is a widely debated issue in modern science. The electrophysiological fields have very tiny intensities and it can be inferred that they are rapidly decreasing with the distance from the generating structure, vanishing at very short distances. This makes very hard their detection using standard experimental methods. However, the existence of fast-moving charged particles in the macromolecules inside both intracellular and extracellular fluids may envisage the generation of localized electric currents as well as the presence of closed loops, which implies the existence of magnetic fields. Moreover, the whole set of oscillatory frequencies of various substances, enzymes, cell membranes, nucleic acids, bioelectrical phenomena generated by the electrical rhythm of coherent groups of cells, cell-to-cell communication among population of host bacteria, forms the increasingly complex hierarchies of electromagnetic signals of different frequencies which cover the living being and represent a fundamental information network controlling the cell metabolism. From this approach emerges the concept of electromagnetic homeostasis: that is, the capability of the human body to maintain the balance of highly complex electromagnetic interactions within, in spite of the external electromagnetic noisy environment. This concept may have an important impact on the actual definitions of heal and disease.

  18. External Field QED on Cauchy Surfaces for Varying Electromagnetic Fields

    NASA Astrophysics Data System (ADS)

    Deckert, D.-A.; Merkl, F.

    2016-08-01

    The Shale-Stinespring Theorem (J Math Mech 14:315-322, 1965) together with Ruijsenaar's criterion (J Math Phys 18(4):720-737, 1977) provide a necessary and sufficient condition for the implementability of the evolution of external field quantum electrodynamics between constant-time hyperplanes on standard Fock space. The assertion states that an implementation is possible if and only if the spatial components of the external electromagnetic four-vector potential {A_μ} are zero. We generalize this result to smooth, space-like Cauchy surfaces and, for general {A_μ}, show how the second-quantized Dirac evolution can always be implemented as a map between varying Fock spaces. Furthermore, we give equivalence classes of polarizations, including an explicit representative, that give rise to those admissible Fock spaces. We prove that the polarization classes only depend on the tangential components of {A_μ} w.r.t. the particular Cauchy surface, and show that they behave naturally under Lorentz and gauge transformations.

  19. Health Effects of Electromagnetic Fields: A Review of Literature.

    ERIC Educational Resources Information Center

    White, George L.; And Others

    1995-01-01

    Current evidence suggests that the effects of electromagnetic fields (EMF) disturb cell homeostasis at very low intensities by influencing discrete intracellular magnetic fields. The article reviews current research about the health effects of EMF, examining historical implications, childhood studies, adult studies, and popular press reports, and…

  20. On guided versus deflected fields in controlled-source electromagnetics

    NASA Astrophysics Data System (ADS)

    Swidinsky, Andrei

    2015-06-01

    The detection of electrically resistive targets in applied geophysics is of interest to the hydrocarbon, mining and geotechnical industries. Elongated thin resistive bodies have been extensively studied in the context of offshore hydrocarbon exploration. Such targets guide electromagnetic fields in a process which superficially resembles seismic refraction. On the other hand, compact resistive bodies deflect current in a process which has more similarities to diffraction and scattering. The response of a real geological structure is a non-trivial combination of these elements-guiding along the target and deflection around its edges. In this note the electromagnetic responses of two end-member models are compared: a resistive layer, which guides the electromagnetic signal, and a resistive cylinder, which deflects the fields. Results show that the response of a finite resistive target tends to saturate at a much lower resistivity than a resistive layer, under identical survey configurations. Furthermore, while the guided electromagnetic fields generated by a buried resistive layer contain both anomalous horizontal and vertical components, the process of electromagnetic deflection from a buried resistive cylinder creates mainly anomalous vertical fields. Finally, the transmitter orientation with respect to the position of a finite body is an important survey parameter: when the distance to the target is much less than the host skin depth, a transmitter pointing towards the resistive cylinder will produce a stronger signal than a transmitter oriented azimuthally with respect to the cylinder surface. The opposite situation is observed when the distance to the target is greater than the host skin depth.

  1. Biological effects of electromagnetic fields and recently updated safety guidelines for strong static magnetic fields.

    PubMed

    Yamaguchi-Sekino, Sachiko; Sekino, Masaki; Ueno, Shoogo

    2011-01-01

    Humans are exposed daily to artificial and naturally occurring magnetic fields that originate from many different sources. We review recent studies that examine the biological effects of and medical applications involving electromagnetic fields, review the properties of static and pulsed electromagnetic fields that affect biological systems, describe the use of a pulsed electromagnetic field in combination with an anticancer agent as an example of a medical application that incorporates an electromagnetic field, and discuss the recently updated safety guidelines for static electromagnetic fields. The most notable modifications to the 2009 International Commission on Non-Ionizing Radiation Protection guidelines are the increased exposure limits, especially for those who work with or near electromagnetic fields (occupational exposure limits). The recommended increases in exposure were determined using recent scientific evidence obtained from animal and human studies. Several studies since the 1994 publication of the guidelines have examined the effects on humans after exposure to high static electromagnetic fields (up to 9.4 tesla), but additional research is needed to ascertain further the safety of strong electromagnetic fields.

  2. Quantum processes in short and intensive electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Titov, A. I.; Kämpfer, Burkhard; Hosaka, Atsushi; Takabe, Hideaki

    2016-05-01

    This work provides an overview of our recent results in studying two most important and widely discussed quantum processes: electron-positron pairs production off a probe photon propagating through a polarized short-pulsed electromagnetic (e.g. laser) wave field or generalized Breit-Wheeler process, and a single a photon emission off an electron interacting with the laser pules, so-called non-linear Compton scattering. We show that the probabilities of particle production in both processes are determined by interplay of two dynamical effects, where the first one is related to the shape and duration of the pulse and the second one is non-linear dynamics of the interaction of charged fermions with a strong electromagnetic field. We elaborate suitable expressions for the production probabilities and cross sections, convenient for studying evolution of the plasma in presence of strong electromagnetic fields.

  3. The effect of pulsed electromagnetic field therapy on food sensitivity.

    PubMed

    Monro, Jean A; Puri, Basant K

    2015-01-01

    Owing to the involvement of the immune system in the etiology of food sensitivity, and because pulsed electromagnetic field therapy is associated with beneficial immunologic changes, it was hypothesized that pulsed electromagnetic fields may have a beneficial effect on food sensitivity. A small pilot study was carried out in patients suffering from food sensitivity, with the antigen leukocyte antibody test being employed to index the degree of food sensitivity in terms of the number of foods to which each patient reacted. It was found that a 1-week course of pulsed electromagnetic field therapy, consisting of one hour's treatment per day, resulted in a reduction in the mean number of reactive foods of 10.75 (p < 0.05). On the basis of these results, a larger study is warranted.

  4. Electromagnetic Propulsion System for Spacecraft using Geomagnetic fields and Superconductors

    NASA Astrophysics Data System (ADS)

    Dadhich, Anang

    This thesis concentrates on developing an innovative method to generate thrust force for spacecraft in localized geomagnetic fields by various electromagnetic systems. The proposed electromagnetic propulsion system is an electromagnet, like normal or superconducting solenoid, having its own magnetic field which interacts with the planet's magnetic field to produce a reaction thrust force. The practicality of the system is checked by performing simulations in order the find the varying radius, velocity, and acceleration changes. The advantages, challenges, various optimization techniques, and viability of such a propulsion system in present day and future are discussed. The propulsion system such developed is comparable to modern MPD Thrusters and electric engines, and has various applications like spacecraft propulsion, orbit transfer and stationkeeping.

  5. Rotating colloids in rotating magnetic fields: Dipolar relaxation and hydrodynamic coupling

    NASA Astrophysics Data System (ADS)

    Coughlan, Anna C. H.; Bevan, Michael A.

    2016-10-01

    Video microscopy (VM) experiments and Brownian dynamics (BD) simulations were used to measure and model superparamagnetic colloidal particles in rotating magnetic fields for interaction energies on the order of the thermal energy, kT . Results from experiments and simulations were compared for isolated particle rotation, particle rotation within doublets, doublet rotation, and separation within doublets vs field rotation frequency. Agreement between VM and BD results was obtained at all frequencies and amplitudes only by including exact two-body hydrodynamic interactions and relevant relaxation times of magnetic dipoles. Frequency-dependent particle forces and torques cause doublets to rotate at low frequencies via dipolar interactions and at high frequencies via hydrodynamic translation-rotation coupling. By matching measurements and simulations for a range of conditions, our findings unambiguously demonstrate the quantitative forms of dipolar and hydrodynamic interactions necessary to capture nonequilibrium, steady-state dynamics of Brownian colloids in magnetic fields.

  6. Kinetic theory of plasma equilibrium in an electromagnetic field

    NASA Astrophysics Data System (ADS)

    Gorbunov, L. M.; Gradov, O. M.; Ziunder, D.; Ramazashvili, R. R.

    1981-04-01

    The present study examines the equilibrium of a direct-current-carrying plasma in an electromagnetic field under the assumption that the particles escaping from the plasma have a Maxwellian distribution. It is shown that an equilibrium state is possible only in the case of a definite relationship between the amplitude of the incident wave and the concentration of escaping particles. Attention is given to spatial variations of the electromagnetic field, and of the plasma density and flow velocity. The application of these effects in microwave devices is discussed.

  7. Near-field thermal electromagnetic transport: An overview

    NASA Astrophysics Data System (ADS)

    Edalatpour, Sheila; DeSutter, John; Francoeur, Mathieu

    2016-07-01

    A general near-field thermal electromagnetic transport formalism that is independent of the size, shape and number of heat sources is derived. The formalism is based on fluctuational electrodynamics, where fluctuating currents due to thermal agitation are added to Maxwell's curl equations, and is thus valid for heat sources in local thermodynamic equilibrium. Using a volume integral formulation, it is shown that the proposed formalism is a generalization of the classical electromagnetic scattering framework in which thermal emission is implicitly assumed to be negligible. The near-field thermal electromagnetic transport formalism is afterwards applied to a problem involving three spheres with size comparable to the wavelength, where all multipolar interactions are taken into account. Using the thermal discrete dipole approximation, it is shown that depending on the dielectric function, the presence of a third sphere slightly affects the spatial distribution of power absorbed compared to the two-sphere case. A transient analysis shows that despite a non-uniform spatial distribution of power absorbed, the sphere temperature remains spatially uniform at any instant due to the fact that the thermal resistance by conduction is much smaller than the resistance by radiation. The formalism proposed in this paper is general, and could be used as a starting point for adapting solution methods employed in traditional electromagnetic scattering problems to near-field thermal electromagnetic transport.

  8. Slowly rotating scalar field wormholes: The second order approximation

    SciTech Connect

    Kashargin, P. E.; Sushkov, S. V.

    2008-09-15

    We discuss rotating wormholes in general relativity with a scalar field with negative kinetic energy. To solve the problem, we use the assumption about slow rotation. The role of a small dimensionless parameter plays the ratio of the linear velocity of rotation of the wormhole's throat and the velocity of light. We construct the rotating wormhole solution in the second-order approximation with respect to the small parameter. The analysis shows that the asymptotical mass of the rotating wormhole is greater than that of the nonrotating one, and the null energy condition violation in the rotating wormhole spacetime is weaker than that in the nonrotating one.

  9. Optimal control of electromagnetic field using metallic nanoclusters

    NASA Astrophysics Data System (ADS)

    Grigorenko, Ilya; Haas, Stephan; Balatsky, Alexander; Levi, A. F. J.

    2008-04-01

    The dielectric properties of metallic nanoclusters in the presence of an applied electromagnetic field are investigated using the non-local linear response theory. In the quantum limit we find a nontrivial dependence of the induced field and charge distributions on the spatial separation between the clusters and on the frequency of the driving field. Using a genetic algorithm, these quantum functionalities are exploited to custom-design sub-wavelength lenses with a frequency-controlled switching capability.

  10. Method for imaging with low frequency electromagnetic fields

    DOEpatents

    Lee, Ki H.; Xie, Gan Q.

    1994-01-01

    A method for imaging with low frequency electromagnetic fields, and for interpreting the electromagnetic data using ray tomography, in order to determine the earth conductivity with high accuracy and resolution. The imaging method includes the steps of placing one or more transmitters, at various positions in a plurality of transmitter holes, and placing a plurality of receivers in a plurality of receiver holes. The transmitters generate electromagnetic signals which diffuse through a medium, such as earth, toward the receivers. The measured diffusion field data H is then transformed into wavefield data U. The traveltimes corresponding to the wavefield data U, are then obtained, by charting the wavefield data U, using a different regularization parameter .alpha. for each transform. The desired property of the medium, such as conductivity, is then derived from the velocity, which in turn is constructed from the wavefield data U using ray tomography.

  11. Method for imaging with low frequency electromagnetic fields

    DOEpatents

    Lee, K.H.; Xie, G.Q.

    1994-12-13

    A method is described for imaging with low frequency electromagnetic fields, and for interpreting the electromagnetic data using ray tomography, in order to determine the earth conductivity with high accuracy and resolution. The imaging method includes the steps of placing one or more transmitters, at various positions in a plurality of transmitter holes, and placing a plurality of receivers in a plurality of receiver holes. The transmitters generate electromagnetic signals which diffuse through a medium, such as earth, toward the receivers. The measured diffusion field data H is then transformed into wavefield data U. The travel times corresponding to the wavefield data U, are then obtained, by charting the wavefield data U, using a different regularization parameter [alpha] for each transform. The desired property of the medium, such as conductivity, is then derived from the velocity, which in turn is constructed from the wavefield data U using ray tomography. 13 figures.

  12. Sensing Random Electromagnetic Fields and Applications

    DTIC Science & Technology

    2015-06-23

    negative forces”, Nature Photonics 7, (2013) 6. D. C. Kohlgraf-Owens, S. Sukhov, and A. Dogariu, “ Near - Field Topography of Light”, Optics and Photonics...8. D. C. Kohlgraf-Owens, S. Sukhov, and A. Dogariu, “Discrimination of Field Components in Optical Probe Microscopy ”, Opt. Lett. 37, 3606 (2012) 9...reduces the optical contrast. The addition of more independent fields further reduces this contrast. However, when a fully polarized and coherent REF

  13. Deformation methods in modelling of the inner magnetospheric electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Toivanen, P. K.

    2007-12-01

    Various deformation methods have been widely used in animation image processing. In common terms, they are mathematical presentations of deformations of an image drawn on an elastic material under stretching or compression of the material. Such a method has also been used in modelling of the magnetospheric magnetic fields, and recently been generalized to include also the electric fields. In this presentations, the theory of the deformation method and an application in a form of a new global magnetospheric electromagnetic field model are previewed. The main focus of the presentation is on the inner magnetospheric current systems and associated electromagnetic fields during quiet and disturbed periods. Finally, a short look at the modern deformation methods in image processing is taken. These methods include the Free Form Deformations and Moving Least Squares Deformations, and their future applications in magnetospheric field modelling are discussed.

  14. Induction of illusory self-rotation and nystagmus by a rotating sound-field

    NASA Technical Reports Server (NTRS)

    Lackner, J. R.

    1977-01-01

    Subjects seated in darkness often experience illusory self-rotation when exposed to a rotating sound field. Compelling illusions of a self-rotation are generally accompanied by nystagmoid movements of the eyes with the slow phase in the direction opposite that of the experienced self-rotation. These phenomena are related to the functioning of a spatial constancy mechanism by which a stable distinction is normally maintained between movements of self and movements of the environment. The appearance of nystagmus during illusory self-rotating indicates that apparent body orientation can influence oculomotor control.

  15. Does three-dimensional electromagnetic field inherit the spacetime symmetries?

    NASA Astrophysics Data System (ADS)

    Cvitan, M.; Dominis Prester, P.; Smolić, I.

    2016-04-01

    We prove that the electromagnetic field in a (1+2)-dimensional spacetime necessarily inherits the symmetries of the spacetime metric in a large class of generalized Einstein-Maxwell theories. The Lagrangians of the studied theories have general diff-covariant gravitational part and include both the gravitational and the gauge Chern-Simons terms.

  16. Transducer measures temperature differentials in presence of strong electromagnetic fields

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Measurement of temperature rise of cooling water under pressure and in strong electromagnetic fields is accomplished by a transducer using a magnetically shielded thermocouple arrangement. The thermocouple junctions are immersed in oil to isolate them from electric currents in the water.

  17. Relativistic Particle in Electromagnetic Fields with a Generalized Uncertainty Principle

    NASA Astrophysics Data System (ADS)

    Merad, M.; Zeroual, F.; Falek, M.

    2012-05-01

    In this paper, we propose to solve the relativistic Klein-Gordon and Dirac equations subjected to the action of a uniform electromagnetic field with a generalized uncertainty principle in the momentum space. In both cases, the energy eigenvalues and their corresponding eigenfunctions are obtained. The limit case is then deduced for a small parameter of deformation.

  18. What Message Should Health Educators Give regarding Electromagnetic Fields?

    ERIC Educational Resources Information Center

    Al-Khamees, Nedaa A.

    2008-01-01

    The possibility of extremely low frequency electromagnetic fields (ELF EMF) causing a number of medical conditions and common symptoms remains a concern and presents somewhat of a quandary to health educators in view of conflicting results. This study investigated the relationship of a number of EMF sources to reported symptoms in an attempt to,…

  19. 78 FR 33633 - Human Exposure to Radiofrequency Electromagnetic Fields

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-04

    ... June 4, 2013 Part IV Federal Communications Commission 47 CFR Parts 1, 2, and 15, et al. Human Exposure..., and 95 Human Exposure to Radiofrequency Electromagnetic Fields AGENCY: Federal Communications... National Environmental Policy Act (NEPA) as they relate to the guidelines for human exposure to...

  20. Oscillator strength sum rules with an external electromagnetic field

    NASA Astrophysics Data System (ADS)

    Cabrera-Trujillo, R.; Sabin, John R.; Öhrn, Yngve; Oddershede, J.

    1998-04-01

    We demonstrate that the Bethe, and therefore the Thomas-Reiche-Kuhn, sum rule is unaffected by the presence of an applied external electromagnetic field in the exact case. We use the consequence that the first-order perturbation contribution must also vanish to derive a necessary condition for the completeness of computational one-electron basis sets.

  1. Note: Design of a novel rotating magnetic field device

    NASA Astrophysics Data System (ADS)

    Godínez, F. A.; Chávez, O.; Zenit, R.

    2012-06-01

    A novel device to produce a rotating magnetic field was designed, constructed, and tested. The system consists of a Helmholtz coil pair which is mechanically coupled to a dc electric motor whose angular velocity is controlled. The coil pair generates a uniform magnetic field; the whole system is rotated maintaining the coils energized using brushes. The magnetic field strength is uniform (≈5.8 mT) for a workspace of about 100 mm along the rotation axis. The system remains free of undesirable high amplitude mechanical vibrations for rotation frequencies below 10 Hz. We verified the performance of the apparatus by conducting experiments with magnetic swimmers.

  2. Effect of magnetic field on the rotating filamentary molecular clouds

    NASA Astrophysics Data System (ADS)

    Aghili, P.; Kokabi, K.

    2017-04-01

    The Purpose of this work is to study the evolution of magnetized rotating filamentary molecular clouds. We consider cylindrical symmetric filamentary molecular clouds at an early stage of evolution. For the first time we consider the rotation of filamentary molecular in the presence of an axial and azimuthal magnetic field without any assumption of density and magnetic functions. We show that in addition to decreasing the radial collapse velocity, the rotational velocity is also affected by the magnetic field. The existence of rotation yields fragmentation of filaments. Moreover, we show that the magnetic field has a significant effect on the fragmentation of filamentary molecular clouds.

  3. Stress field rotation or block rotation: An example from the Lake Mead fault system

    NASA Technical Reports Server (NTRS)

    Ron, Hagai; Nur, Amos; Aydin, Atilla

    1990-01-01

    The Coulomb criterion, as applied by Anderson (1951), has been widely used as the basis for inferring paleostresses from in situ fault slip data, assuming that faults are optimally oriented relative to the tectonic stress direction. Consequently if stress direction is fixed during deformation so must be the faults. Freund (1974) has shown that faults, when arranged in sets, must generally rotate as they slip. Nur et al., (1986) showed how sufficiently large rotations require the development of new sets of faults which are more favorably oriented to the principal direction of stress. This leads to the appearance of multiple fault sets in which older faults are offset by younger ones, both having the same sense of slip. Consequently correct paleostress analysis must include the possible effect of fault and material rotation, in addition to stress field rotation. The combined effects of stress field rotation and material rotation were investigated in the Lake Meade Fault System (LMFS) especially in the Hoover Dam area. Fault inversion results imply an apparent 60 degrees clockwise (CW) rotation of the stress field since mid-Miocene time. In contrast structural data from the rest of the Great Basin suggest only a 30 degrees CW stress field rotation. By incorporating paleomagnetic and seismic evidence, the 30 degrees discrepancy can be neatly resolved. Based on paleomagnetic declination anomalies, it is inferred that slip on NW trending right lateral faults caused a local 30 degrees counter-clockwise (CCW) rotation of blocks and faults in the Lake Mead area. Consequently the inferred 60 degrees CW rotation of the stress field in the LMFS consists of an actual 30 degrees CW rotation of the stress field (as for the entire Great Basin) plus a local 30 degrees CCW material rotation of the LMFS fault blocks.

  4. [Clinical monitoring in areas of exposure to radiofrequency electromagnetic fields].

    PubMed

    Suvorov, I M

    2013-01-01

    Clinical syndromes induced by high intensity radiofrequency electromagnetic field chronic exposure are described. Persons injured by occupational exposure have been observed central nervous system changes in diencephalic syndrome form, cardio-vascular system changes revealed in atherosclerosis, isch(a)emic heart disease and coronary insufficiency rapid progressive expansion. General public living in territory of radar station exposure zone different functional disorders have been identified: vegetative dystonia (asthenovegetative syndrome), thrombocytopenia, decrease of blood coagulation index, and thyroid gland function changes. Observed diseases clinical variability may be determined by electromagnetic exposure characteristics.

  5. Electromagnetic fields from mobile phone base station - variability analysis.

    PubMed

    Bienkowski, Pawel; Zubrzak, Bartlomiej

    2015-09-01

    The article describes the character of electromagnetic field (EMF) in mobile phone base station (BS) surroundings and its variability in time with an emphasis on the measurement difficulties related to its pulse and multi-frequency nature. Work also presents long-term monitoring measurements performed recently in different locations in Poland - small city with dispersed building development and in major polish city - dense urban area. Authors tried to determine the trends in changing of EMF spectrum analyzing daily changes of measured EMF levels in those locations. Research was performed using selective electromagnetic meters and also EMF meter with spectrum analysis.

  6. Generation of shear Alfven waves by a rotating magnetic field source: Three-dimensional simulations

    SciTech Connect

    Karavaev, A. V.; Gumerov, N. A.; Papadopoulos, K.; Shao, Xi; Sharma, A. S.; Gekelman, W.; Wang, Y.; Van Compernolle, B.; Pribyl, P.; Vincena, S.

    2011-03-15

    The paper discusses the generation of polarized shear Alfven waves radiated from a rotating magnetic field source created via a phased orthogonal two-loop antenna. A semianalytical three-dimensional cold two-fluid magnetohydrodynamics model was developed and compared with recent experiments in the University of California, Los Angeles large plasma device. Comparison of the simulation results with the experimental measurements and the linear shear Alfven wave properties, namely, spatiotemporal wave structure, a dispersion relation with nonzero transverse wave number, the magnitude of the wave dependences on the wave frequency, show good agreement. From the simulations it was found that the energy of the Alfven wave generated by the rotating magnetic field source is distributed between the kinetic energy of ions and electrons and the electromagnetic energy of the wave as: {approx}1/2 is the energy of the electromagnetic field, {approx}1/2 is the kinetic energy of the ion fluid, and {approx}2.5% is the kinetic energy of electron fluid for the experiment. The wave magnetic field power calculated from the experimental data and using a fluid model differ by {approx}1% and is {approx}250 W for the experimental parameters. In both the experiment and the three-dimensional two-fluid magnetohydrodynamics simulations the rotating magnetic field source was found to be very efficient for generating shear Alfven waves.

  7. Collisionless Magnetic Reconnection and Dynamo Processes in a Spatially Rotating Magnetic Field

    NASA Astrophysics Data System (ADS)

    Choe, Gwangson; Lee, Junggi

    2016-04-01

    Spatially rotating magnetic fields have been observed in the solar wind and in the Earth's magnetopause as well as in reversed field pinch (RFP) devices. Such field configurations have a similarity with extended current layers having a spatially varying plasma pressure instead of the spatially varying guide field. It is thus expected that magnetic reconnection may take place in a rotating magnetic field no less than in an extended current layer. We have investigated the spontaneous evolution of a collisionless plasma system embedding a rotating magnetic field with a two-and-a-half-dimensional electromagnetic particle-in-cell (PIC) simulation. It is found that a magnetic-flux-reducing diffusion phase and a magnetic-flux-increasing dynamo phase are alternating with a certain period. The temperature of the system also varies with the same period, showing a similarity to sawtooth oscillations in tokamaks. We have shown that a modified theory of sawtooth oscillations can explain the periodic behavior observed in the simulation. A strong guide field distorts the current layer as was observed in laboratory experiments. This distortion is smoothed out as magnetic islands fade away by the O-line diffusion, but is soon strengthened by the growth of magnetic islands. These processes are all repeating with a fixed period. Our results suggest that a rotating magnetic field configuration continuously undergoes deformation and relaxation in a short time-scale although it might look rather steady in a long-term view.

  8. Numerical Analysis of Electromagnetic Fields in Multiscale Model

    NASA Astrophysics Data System (ADS)

    Ma, Ji; Fang, Guang-You; Ji, Yi-Cai

    2015-04-01

    Modeling technique for electromagnetic fields excited by antennas is an important topic in computational electromagnetics, which is concerned with the numerical solution of Maxwell's equations. In this paper, a novel hybrid technique that combines method of moments (MoM) with finite-difference time-domain (FDTD) method is presented to handle the problem. This approach employed Huygen's principle to realize the hybridization of the two classical numerical algorithms. For wideband electromagnetic data, the interpolation scheme is used in the MoM based on the dyadic Green's function. On the other hand, with the help of equivalence principle, the scattered electric and magnetic fields on the Huygen's surface calculated by MoM are taken as the sources for FDTD. Therefore, the electromagnetic fields in the environment can be obtained by employing finite-difference time-domain method. Finally, numerical results show the validity of the proposed technique by analyzing two canonical samples. Supported in part by China Postdoctoral Science Foundation under Grant No. 201M550839, and in part by the Key Research Program of the Chinese Academy of Sciences under Grant No. KGZD-EW-603

  9. Basic Materials for Electromagnetic Field Standards

    DTIC Science & Technology

    2003-03-04

    UHF bio- logical effects. VIEM, 1937. 8. Anikin M.M., Varshaver G.S. Basics of a physiotherapy . Medgiz. 1950. 9. Osipov You.A., Ushinskaya O.F. On... strokes a 1 minute. Table. Frequency drift of frog heart beats in dependence from modulations of microwave field and initial frequency of heart...hearts with frequency of beats of 20–30 strokes a 1 minute. 23 EXAMINATIONS IN VIVO It was supposed, that the role of modulation in

  10. Electromagnetic Field Effects in Semiconductor Crystal Growth

    NASA Technical Reports Server (NTRS)

    Dulikravich, George S.

    1996-01-01

    This proposed two-year research project was to involve development of an analytical model, a numerical algorithm for its integration, and a software for the analysis of a solidification process under the influence of electric and magnetic fields in microgravity. Due to the complexity of the analytical model that was developed and its boundary conditions, only a preliminary version of the numerical algorithm was developed while the development of the software package was not completed.

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

    NASA Technical Reports Server (NTRS)

    El-Kaddah, N.; Szekely, J.

    1982-01-01

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

  12. The Earth-Moon-Sun natural laboratory for testing of gravitational and electromagnetic fields coupling

    NASA Astrophysics Data System (ADS)

    Grunskaya, Lubov; Isakevich, Valiriy; Efimov, Vladislav; Zakirov, Alexander

    Experimental investigations of electromagnetic fields in the atmosphere boundary layer are done at the distance spaced stations, situated on VSU test ground, at Main Geophysical Observa-tory(St. Petersburg), on Kamchatka pen., on Lake Baikal. The distance spaced reception of electrical and magnetic fields will allow to analyze more widely the nature of the investigated interactions. Monitoring of electromagnetic fields in the ELF range is being realized. The work is connected with search of interconnection of the electromagnetic field of the atmosphere boundary layer with the gravitational Compact Binaries wave fields. For analyzing Compact Binaries were taken with ELF of GW-radiation: J 0700+6418, J 1012+5307, J 1537+1155, J 1959+2048, J 2130+1210, J 1915+1606, J 1910+0004, J 1910+0004, J 1748-2446A.For analyz-ing the spectrum of the magnetic fields there was used the information of VSU station and the monitoring information of Japanese geomagnetic stations Kakioka and Mambetsu. The aim of such investigations is connected with displaying tide processes (the Moon tides) and gravita-tional wave influence of Compact Binaries in the electromagnetic fields.On the first stage of the investigations a correlative spectral analysis of the experimental data was being carried out. There was factually extracted the influence of the atmosphere lower layer electromagnetic field of the thermogravitational solar tides and a number of gravitational: M1, M2, N2. It was ob-tained that astrophysical sources GV-6, GV-3,GV-4, GV-8, GV-9 have the most probability of non-casual of events. The subsequent investigations are connected with search of main features accompanying such influences. They are signal modulations by diurnal and year's rotation of the Earth. Such modulations are peculiar to sources of non-terrestrial origin. We are planning an extraction of the radiation frequency change of the source because of energy loss for the radiation of GW. Such investigations turned out to be

  13. On the concept of random orientation in far-field electromagnetic scattering by nonspherical particles.

    PubMed

    Mishchenko, Michael I; Yurkin, Maxim A

    2017-02-01

    Although the model of randomly oriented nonspherical particles has been used in a great variety of applications of far-field electromagnetic scattering, it has never been defined in strict mathematical terms. In this Letter, we use the formalism of Euler rigid-body rotations to clarify the concept of statistically random particle orientations and derive its immediate corollaries in the form of the most general mathematical properties of the orientation-averaged extinction and scattering matrices. Our results serve to provide a rigorous mathematical foundation for numerous publications in which the notion of randomly oriented particles and its light-scattering implications have been considered intuitively obvious.

  14. Generation of whistler waves by a rotating magnetic field source

    SciTech Connect

    Karavaev, A. V.; Gumerov, N. A.; Papadopoulos, K.; Shao, Xi; Sharma, A. S.; Gekelman, W.; Gigliotti, A.; Pribyl, P.; Vincena, S.

    2010-01-15

    The paper discusses the generation of polarized whistler waves radiated from a rotating magnetic field source created via a novel phased orthogonal two loop antenna. The results of linear three-dimensional electron magnetohydrodynamics simulations along with experiments on the generation whistler waves by the rotating magnetic field source performed in the large plasma device are presented. Comparison of the experimental results with the simulations and linear wave properties shows good agreement. The whistler wave dispersion relation with nonzero transverse wave number and the wave structure generated by the rotating magnetic field source are also discussed. The phase velocity of the whistler waves was found to be in good agreement with the theoretical dispersion relation. The exponential decay rate of the whistler wave propagating along the ambient magnetic field is determined by Coulomb collisions. In collisionless case the rotating magnetic field source was found to be a very efficient radiation source for transferring energy along the ambient magnetic field lines.

  15. Magnetic and antimagnetic rotation in 110Cd within tilted axis cranking relativistic mean-field theory

    NASA Astrophysics Data System (ADS)

    Peng, J.; Zhao, P. W.

    2015-04-01

    The self-consistent tilted axis cranking relativistic mean-field (TAC-RMF) theory based on a point-coupling interaction is applied to investigate the observed magnetic and antimagnetic rotations in the nucleus 110Cd . The energy spectra, the relation between the spin and the rotational frequency, the deformation parameters, and the reduced M 1 and E 2 transition probabilities are studied with the various configurations. It is found that the configuration has to be changed to reproduce the energy spectra and the relations between the spin and the rotational frequency for both the magnetic and antimagnetic rotational bands. The shears mechanism for the magnetic rotation and the two-shears-like mechanism for the antimagnetic rotation are examined by investigating the orientation of the neutron and proton angular momenta. The calculated electromagnetic transitions B (M 1 ) and B (E 2 ) are in reasonable agreement with the data, and their tendencies are coincident with the typical characteristics of the magnetic and antimagnetic rotations.

  16. Controllable rotating behavior of individual dielectric micro-rod in a rotating electric field.

    PubMed

    Liu, Weiyu; Ren, Yukun; Tao, Ye; Li, Yanbo; Chen, Xiaoming

    2017-02-18

    We report herein controllable rotating behavior of an individual dielectric micro-rod driven by a background rotating electric field. By disposing or removing structured floating microelectrode, the rigid rod suspended in electrolyte solution accordingly exhibits co-field or anti-field rotating motion. In the absence of the ideally polarizable metal surface, the dielectric rod rotates opposite to propagation of electric field, with the measured rotating rate much larger than predicted by Maxwell-Wager interfacial polarization theory incorporating surface conduction of fixed bond charge. Surprisingly, with floating electrode embedded, a novel kind of co-field rotation mode occurs in the presence of induced double-layer polarization, due to the action of hydrodynamic torque from rotating induced-charge electroosmosis. This method of achieving switchable spin modes of dielectric particles would direct implications in constructing flexible electrokinetic framework for analyzing 3D profile of on-chip bio-microfluidic samples. This article is protected by copyright. All rights reserved.

  17. [New mechanisms of biological effects of electromagnetic fields].

    PubMed

    Buchachenko, A L; Kuznetsov, D A; Berdinskiĭ, V L

    2006-01-01

    The production of ATP in mitochondria depends on the magnesium nuclear spin and magnetic moment of a Mg2+ ion in creatine kinase and ATPase. This suggests that enzymatic synthesis of ATP is an ion-radical process and thus depends on the external magnetic field (magnetobiology originates from this fact) and microwave fields, which control the spin states of ion-radical pairs and affect the ATP synthesis. The chemical mechanism of ATP synthesis and the origin of biological effects of electromagnetic (microwave) fields are discussed.

  18. Invariant superoscillatory electromagnetic fields in 3D-space

    NASA Astrophysics Data System (ADS)

    Makris, K. G.; Papazoglou, D. G.; Tzortzakis, S.

    2017-01-01

    We derive exact solutions of Maxwell’s equations based on superoscillatory superpositions of vectorial Bessel beams. These novel beams are diffraction-free and can support subwavelength features in their transverse electromagnetic fields, without the presence of any evanescent waves. These features can be propagated into the far field. Approximate solutions in closed form are also derived based on asymptotic expansions of Bessel functions for simple prescribed subwavelength patterns. The superoscillatory characteristics of both electric, magnetic field components (transverse and longitudinal), and the Poynting vector, as well as, the effect of nonparaxiality are systematically investigated.

  19. Soft hairs on isolated horizon implanted by electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Mao, Pujian; Wu, Xiaoning; Zhang, Hongbao

    2017-03-01

    Inspired by the recent proposal of soft hair on black holes in Hawking et al (2016 Phys. Rev. Lett. 116 231301), we have shown that an isolated horizon carries soft hairs implanted by electromagnetic fields. The solution space and the asymptotic symmetries of Einstein–Maxwell theory have been worked out explicitly near the isolated horizon. The conserved current has been computed and an infinite number of near horizon charges have been introduced from the electromagnetic fields associated with the asymptotic U(1) symmetry near the horizon, which indicates the fact that the isolated horizon carries a large amount of soft electric hairs. The soft electric hairs, i.e. asymptotic U(1) charges, are shown to be equivalent to the electric multipole moments of isolated horizons. It is further argued that the isolated horizon supertranslation is from the ambiguity of its foliation and an analogue of memory effect on horizon can be expected.

  20. Controversies related to electromagnetic field exposure on peripheral nerves.

    PubMed

    Say, Ferhat; Altunkaynak, Berrin Zuhal; Coşkun, Sina; Deniz, Ömür Gülsüm; Yıldız, Çağrı; Altun, Gamze; Kaplan, Arife Ahsen; Kaya, Sefa Ersan; Pişkin, Ahmet

    2016-09-01

    Electromagnetic field (EMF) is a pervasive environmental presence in modern society. In recent years, mobile phone usage has increased rapidly throughout the world. As mobile phones are generally held close to the head while talking, studies have mostly focused on the central and peripheral nervous system. There is a need for further research to ascertain the real effect of EMF exposure on the nervous system. Several studies have clearly demonstrated that EMF emitted by cell phones could affect the systems of the body as well as functions. However, the adverse effects of EMF emitted by mobile phones on the peripheral nerves are still controversial. Therefore, this review summarizes current knowledge on the possible positive or negative effects of electromagnetic field on peripheral nerves.

  1. Low-frequency electromagnetic field in a Wigner crystal

    SciTech Connect

    Stupka, Anton

    2013-03-15

    Long-wave low-frequency oscillations are described in a Wigner crystal by generalization of the reverse continuum model for the case of electronic lattice. The internal self-consistent long-wave electromagnetic field is used to describe the collective motions in the system. The eigenvectors and eigenvalues of the obtained system of equations are derived. The velocities of longitudinal and transversal sound waves are found.

  2. Immunorehabilitating effect of ultrahigh frequency electromagnetic fields in immunocompromised animals.

    PubMed

    Pershin, S B; Bobkova, A S; Derevnina, N A; Sidorov, V D

    2013-06-01

    We observed immunorehabilitation effects of ultrahigh frequency electromagnetic fields (microwaves) in immunocompromised animals. It was shown that microwave irradiation of the thyroid gland area could abolish actinomycin D- and colchicine-induced immunosuppression and did not affect immunosuppression caused by 5-fluorouracil. These findings suggest that changes in the hormonal profile of the organism during microwave exposure can stimulate the processes of transcription and mitotic activity of lymphoid cells.

  3. Immune Response to Electromagnetic Fields through Cybernetic Modeling

    NASA Astrophysics Data System (ADS)

    Godina-Nava, J. J.; Segura, M. A. Rodríguez; Cadena, S. Reyes; Sierra, L. C. Gaitán

    2008-08-01

    We study the optimality of the humoral immune response through a mathematical model, which involves the effect of electromagnetic fields over the large lymphocytes proliferation. Are used the so called cybernetic variables in the context of the matching law of microeconomics or mathematical psychology, to measure the large lymphocytes population and to maximize the instantaneous antibody production rate in time during the immunologic response in order to most efficiently inactivate the antigen.

  4. Systemic Effects of Electromagnetic Fields in Patients with Myocardial Infarction

    NASA Astrophysics Data System (ADS)

    Cañedo-Dorantes, L.; Valle, L.; Uruchurtu, E.; Medel, A.; García-Mayen, F.; Serrano-Luna, G.

    2003-09-01

    Healing of acute myocardial infarction (AMI) is associated with inflammatory response, which promotes healing and scar formation. Activation of a local inflammatory response in patients with sequel of AMI could have an important role to enhance angiogenesis and regeneration of hibernating myocardial tissue. Chronic arterial leg ulcers have a similar etiology, and healing has been promoted by exposure to extremely low frequency electromagnetic fields (ELF). We report the evolution of three AMI patients with sequel of AMI that were exposed to ELF.

  5. Immune Response to Electromagnetic Fields through Cybernetic Modeling

    SciTech Connect

    Godina-Nava, J. J.; Segura, M. A. Rodriguez; Cadena, S. Reyes; Sierra, L. C. Gaitan

    2008-08-11

    We study the optimality of the humoral immune response through a mathematical model, which involves the effect of electromagnetic fields over the large lymphocytes proliferation. Are used the so called cybernetic variables in the context of the matching law of microeconomics or mathematical psychology, to measure the large lymphocytes population and to maximize the instantaneous antibody production rate in time during the immunologic response in order to most efficiently inactivate the antigen.

  6. Effects of Pulsed Electromagnetic Fields on Osteoporosis Model

    NASA Astrophysics Data System (ADS)

    Xiaowei, Yang; Liming, Wang; Guan, Z. C.; Yaou, Zhang; Xiangpeng, Wang

    The purpose of this paper was to investigate the preventive effects and long term effects of extremely low frequency pulsed electromagnetic fields (PEMFs), generated by circular coils and pulsed electromagnetic fields stimulators, on osteoporosis in bilaterally ovariectomized rats. In preventive experiment, thirty three-month old female Sprague-Dawley rats were randomly divided into three different groups: sham (SHAM), ovariectomy (OVX), PEMFs stimulation (PEMFs). All rats were subjected to bilaterally ovariectomy except those in SHAM group. The PEMFs group was exposed to pulsed electromagnetic fields with frequency 15 Hz, peak magnetic induction density 2.2mT and exposure time 2 hours per day. The bone mineral density (BMD) of vertebra and left femur were measured by dual energy X-ray absorptiometry at eighth week, twelfth week and sixteenth week after surgery. In long term effects experiment, forty four rats were randomly divided into sham (14 rats, SHAM), ovariectomy group (10 rats, OVX), 15Hz PEMFs group(10 rats, 15Hz) and 30Hz PEMFs group(10 rats, 30Hz) at twenty-sixth week after surgery. Rats in PEMFs groups were stimulated sixteen weeks. In preventive experiment, the Corrected BMD of vertebra and femur was significantly higher than that of OVX group after 16 weeks (P<0.001, P<0.001 respectively). In long term effects experiment, the vertebral BMD of 15Hz PEMFs group and 30Hz PEMFs group was significantly higher than that of OVX groups (P<0.01, P<0.05 respectively). The experimental results demonstrated that extremely low intensity, low frequency, single pulsed electromagnetic fields significantly slowed down the loss of corrected vertebral and femoral BMD in bilaterally ovariectomized rats and suggest that PEMFs may be beneficial in the treatment of osteoporosis.

  7. Low-frequency electromagnetic instabilities caused by a rotating dust flow

    SciTech Connect

    Prudskikh, V. V.

    2010-12-15

    Low-frequency electromagnetic waves propagating obliquely to an external magnetic field in a plasma with an anisotropic dust component are considered. The cold dust is assumed to have considerable longitudinal and transverse velocity components with respect to the magnetic field. A dispersion relation demonstrating that both fast and slow waves can be unstable is derived in the framework of kinetic theory. Mechanisms and consequences of these instabilities are discussed in the context of the problem of plasma transition into a turbulent state behind the shock front of a supernova.

  8. On the Sound Field of a Rotating Propeller

    NASA Technical Reports Server (NTRS)

    Gutin, L.

    1948-01-01

    The sound field of a rotating propeller is teated theoretically on the basis of aerodynamic principles. For the lower harmonics, the directional characteristics and the radiated sound energy are determined and are in conformity with existing experimental results.

  9. Influence of electromagnetic signal of antibiotics excited by low-frequency pulsed electromagnetic fields on growth of Escherichia coli.

    PubMed

    Ke, Yin-Lung; Chang, Fu-Yu; Chen, Ming-Kun; Li, Shun-Lai; Jang, Ling-Sheng

    2013-01-01

    Energy medicine (EM) provides a new medical choice for patients, and its advantages are the noninvasive detection and nondrug treatment. An electromagnetic signal, a kind of EM, induced from antibiotic coupling with weak, extremely low-frequency pulsed electromagnetic fields (PEMFs) is utilized for investigating the growth speed of Escherichia coli (E. coli). PEMFs are produced by solenoidal coils for coupling the electromagnetic signal of antibiotics (penicillin). The growth retardation rate (GRR) of E. coli is used to investigate the efficacy of the electromagnetic signal of antibiotics. The E. coli is cultivated in the exposure of PEMFs coupling with the electromagnetic signal of antibiotics. The maximum GRR of PEMFs with and without the electromagnetic signal of antibiotics on the growth of E. coli cells in the logarithmic is 17.4 and 9.08%, respectively. The electromagnetic signal of antibiotics is successfully coupled by the electromagnetic signal coupling instrument to affect the growth of E. coli. In addition, the retardation effect on E. coli growth can be improved of by changing the carrier frequency of PEMFs coupling with the electromagnetic signal of antibiotics. GRR caused by the electromagnetic signal of antibiotics can be fixed by a different carrier frequency in a different phase of E. coli growth.

  10. Reconstruction of velocity fields in electromagnetic flow tomography.

    PubMed

    Lehtikangas, Ossi; Karhunen, Kimmo; Vauhkonen, Marko

    2016-06-28

    Electromagnetic flow meters (EMFMs) are the gold standard in measuring flow velocity in process industry. The flow meters can measure the mean flow velocity of conductive liquids and slurries. A drawback of this approach is that the velocity field cannot be determined. Asymmetric axial flows, often encountered in multiphase flows, pipe elbows and T-junctions, are problematic and can lead to serious systematic errors. Recently, electromagnetic flow tomography (EMFT) has been proposed for measuring velocity fields using several coils and a set of electrodes attached to the surface of the pipe. In this work, a velocity field reconstruction method for EMFT is proposed. The method uses a previously developed finite-element-based computational forward model for computing boundary voltages and a Bayesian framework for inverse problems. In the approach, the vz-component of the velocity field along the longitudinal axis of the pipe is estimated on the pipe cross section. Different asymmetric velocity fields encountered near pipe elbows, solids-in-water flows in inclined pipes and in stratified or multiphase flows are tested. The results suggest that the proposed reconstruction method could be used to estimate velocity fields in complicated pipe flows in which the conventional EMFMs have limited accuracy. This article is part of the themed issue 'Supersensing through industrial process tomography'.

  11. Rotating Capacitor Measures Steady Electric Fields

    NASA Technical Reports Server (NTRS)

    Johnston, A. R.; Kirkham, H.; Eng, B.

    1986-01-01

    Portable sensor measures electric fields created by dc powerlines or other dc-high-voltage sources. Measures fields from 70 to 50,000 V/m with linearity of 2 percent. Sensor used at any height above ground. Measures both magnitude and direction of field and provides signals representing these measurements to remote readout device. Sensor functions with minimal disturbance of field it is measuring.

  12. Electromagnetic field properties in the vicinity of a massive wormhole

    SciTech Connect

    Novikov, I. D.; Shatskiy, A. A.

    2011-12-15

    It is proved that not only massless but also traversable massive wormholes can have electromagnetic 'hair.' An analysis is also presented of the passage from a traversable wormhole to the limit of a Reissner-Nordstroem black hole, with the corresponding disappearance of 'hair.' A general method is developed for solving stationary axisymmetric Maxwell's equations in the field of a massive, spherically symmetric wormhole. As a particular example of application of the method, a solution is found to the axisymmetric magnetostatic problem for a current loop in the field of the Bronnikov-Ellis-Morris-Thorne wormhole.

  13. Electromagnetic field redistribution in hybridized plasmonic particle-film system

    NASA Astrophysics Data System (ADS)

    Fang, Yurui; Huang, Yingzhou

    2013-04-01

    Combining simulation and experiment, we demonstrate that a metal nanoparticle dimer on a gold film substrate can confine more energy in the particle/film gap because of the hybridization of the dimer resonant lever and the continuous state of the film. The hybridization may even make the electric field enhancement in the dimer/film gap stronger than in the gap between particles. The resonant peak can be tuned by varying the size of the particles and the film thickness. This electromagnetic field redistribution has tremendous applications in sensor, photocatalysis and solar cell, etc., especially considering ultrasensitive detection of tracing molecule on substrates.

  14. Synergistic health effects between chemical pollutants and electromagnetic fields.

    PubMed

    Ledoigt, Gérard; Sta, Chaima; Goujon, Eric; Souguir, Dalila; El Ferjani, Ezzeddine

    2015-01-01

    Humans and ecosystems are exposed to highly variable and unknown cocktail of chemicals and radiations. Although individual chemicals are typically present at low concentrations, they can interact with each other resulting in additive or potentially synergistic mixture effects. This was also observed with products obtained by radiation actions such as sunlight or electromagnetic fields that can change the effects of chemicals, such as pesticides, and metal trace elements on health. Concomitant presence of various pesticides and their transformation products adds further complexity to chemical risk assessment since chronic inflammation is a key step for cancer promotion. Degradation of a parent molecule can produce several by-products which can trigger various toxic effects with different impacts on health and environment. For instance, the cocktail of sunlight irradiated sulcotrione pesticide has a greater cytotoxicity and genotoxicity than parent molecule, sulcotrione, and questions about the impact of photochemical process on environment. Adjuvants were shown to modify the biological features of pesticides. Addition of other elements, metals or biological products, can differently enhance cell toxicity of pesticides or electromagnetic radiations suggesting a synergy in living organisms. Electromagnetic fields spreading, pesticide by-products and mixtures monitoring become greater for environmental contamination evaluations.

  15. Electromagnetic field occupational exposure: non-thermal vs. thermal effects.

    PubMed

    Israel, M; Zaryabova, V; Ivanova, M

    2013-06-01

    There are a variety of definitions for "non-thermal effects" included in different international standards. They start by the simple description that they are "effects of electromagnetic energy on a body that are not heat-related effects", passing through the very general definition related to low-level effects: "biological effects ascribed to exposure to low-level electric, magnetic and electromagnetic fields, i.e. at or below the corresponding dosimetric reference levels in the frequency range covered in this standard (0 Hz-300 GHz)", and going to the concrete definition of "the stimulation of muscles, nerves, or sensory organs, vertigo or phosfenes". Here, we discuss what kind of effect does the non-thermal one has on human body and give data of measurements in different occupations with low-frequency sources of electromagnetic field such as electric power distribution systems, transformers, MRI systems and : video display units (VDUs), whereas thermal effects should not be expected. In some of these workplaces, values above the exposure limits could be found, nevertheless that they are in the term "non-thermal effects" on human body. Examples are workplaces in MRI, also in some power plants. Here, we will not comment on non-thermal effects as a result of RF or microwave exposure because there are not proven evidence about the existance of such effects and mechanisms for them are not clear.

  16. Neutron spin turners with a rotating magnetic field: first experiments

    NASA Astrophysics Data System (ADS)

    Bodnarchuk, V. I.; Kraan, W. H.; Rekveldt, M. T.; Ioffe, A.

    2008-03-01

    Spin turners are the key elements of a neutron spin-echo spectrometer with rotating magnetic fields. Here we describe the results of experiments with thin-film spin turners made of 25 µm amorphous ferromagnetic foils, whose in-plane magnetization is rotated by a weak external rotating field. The behaviour of the polarization vector of a 0.2 nm neutron beam is analysed in 3D after transmission through such a foil and, apart from a non-negligible depolarization, the results show that they are in good accordance with simulations. This observed depolarization is due to a domain structure with a net magnetization.

  17. Plasma effects in electromagnetic field interaction with biological tissue

    NASA Astrophysics Data System (ADS)

    Sharma, R. P.; Batra, Karuna; Excell, Peter S.

    2011-02-01

    Theoretical analysis is presented of the nonlinear behavior of charge carriers in biological tissue under the influence of varying low-intensity electromagnetic (EM) field. The interaction occurs because of the nonlinear force arising due to the gradient of the EM field intensity acting on free electrons in the conduction band of proteins in metabolically active biological cell membrane receptors leading to a redistribution of charge carriers. Field dependence of the resulting dielectric constant is investigated by a suitable modification to include an additional electronic contribution term to the three-term Debye model. The exogenous EM field propagating in this nonlinear cellular medium satisfies the nonlinear Schrödinger equation and can be affected significantly. Resulting field effect can be substantially augmented and effective rectification/demodulation can occur. Possible implications of this modification on biological processes in white and grey matter are discussed.

  18. New Limits on Extragalactic Magnetic Fields from Rotation Measures

    NASA Astrophysics Data System (ADS)

    Pshirkov, M. S.; Tinyakov, P. G.; Urban, F. R.

    2016-05-01

    We take advantage of the wealth of rotation measures data contained in the NRAO VLA Sky Survey catalog to derive new, statistically robust, upper limits on the strength of extragalactic magnetic fields. We simulate the extragalactic magnetic field contribution to the rotation measures for a given field strength and correlation length, by assuming that the electron density follows the distribution of Lyman-α clouds. Based on the observation that rotation measures from distant radio sources do not exhibit any trend with redshift, while the extragalactic contribution instead grows with distance, we constrain fields with Jeans' length coherence length to be below 1.7 nG at the 2 σ level, and fields coherent across the entire observable Universe below 0.65 nG. These limits do not depend on the particular origin of these cosmological fields.

  19. Noise induced calcium oscillations in a cell exposed to electromagnetic fields.

    PubMed

    Zhang, Yuhong; Zhao, Yongli; Chen, Yafei; Yuan, Changqing; Zhan, Yong

    2015-01-01

    The effects of noise on the calcium oscillations in a cell exposed to electromagnetic fields are described by a dynamic model. Noise is a very important factor to be considered in the dynamic research on the calcium oscillations in a cell exposed to electromagnetic fields. Some meaningful results have been obtained here based on the discussion. The results show that the pattern of intracellular calcium oscillations exposure to electromagnetic fields can be influenced by noise. Furthermore, the intracellular calcium oscillations exposure to electromagnetic fields can also be induced by noise. And the work has also studied the relationships between the voltage sensitive calcium channel's open probability and electromagnetic field. The result can provide new insights into constructive roles and potential applications of selecting appropriate electromagnetic field frequency during the research of biological effect of electromagnetic field.

  20. Biological effects from electromagnetic field exposure and public exposure standards.

    PubMed

    Hardell, Lennart; Sage, Cindy

    2008-02-01

    During recent years there has been increasing public concern on potential health risks from power-frequency fields (extremely low frequency electromagnetic fields; ELF) and from radiofrequency/microwave radiation emissions (RF) from wireless communications. Non-thermal (low-intensity) biological effects have not been considered for regulation of microwave exposure, although numerous scientific reports indicate such effects. The BioInitiative Report is based on an international research and public policy initiative to give an overview of what is known of biological effects that occur at low-intensity electromagnetic fields (EMFs) exposure. Health endpoints reported to be associated with ELF and/or RF include childhood leukaemia, brain tumours, genotoxic effects, neurological effects and neurodegenerative diseases, immune system deregulation, allergic and inflammatory responses, breast cancer, miscarriage and some cardiovascular effects. The BioInitiative Report concluded that a reasonable suspicion of risk exists based on clear evidence of bioeffects at environmentally relevant levels, which, with prolonged exposures may reasonably be presumed to result in health impacts. Regarding ELF a new lower public safety limit for habitable space adjacent to all new or upgraded power lines and for all other new constructions should be applied. A new lower limit should also be used for existing habitable space for children and/or women who are pregnant. A precautionary limit should be adopted for outdoor, cumulative RF exposure and for cumulative indoor RF fields with considerably lower limits than existing guidelines, see the BioInitiative Report. The current guidelines for the US and European microwave exposure from mobile phones, for the brain are 1.6 W/Kg and 2 W/Kg, respectively. Since use of mobile phones is associated with an increased risk for brain tumour after 10 years, a new biologically based guideline is warranted. Other health impacts associated with exposure to

  1. The universal C*-algebra of the electromagnetic field II. Topological charges and spacelike linear fields

    NASA Astrophysics Data System (ADS)

    Buchholz, Detlev; Ciolli, Fabio; Ruzzi, Giuseppe; Vasselli, Ezio

    2017-02-01

    Conditions for the appearance of topological charges are studied in the framework of the universal C*-algebra of the electromagnetic field, which is represented in any theory describing electromagnetism. It is shown that non-trivial topological charges, described by pairs of fields localised in certain topologically non-trivial spacelike separated regions, can appear in regular representations of the algebra only if the fields depend non-linearly on the mollifying test functions. On the other hand, examples of regular vacuum representations with non-trivial topological charges are constructed, where the underlying field still satisfies a weakened form of "spacelike linearity". Such representations also appear in the presence of electric currents. The status of topological charges in theories with several types of electromagnetic fields, which appear in the short distance (scaling) limit of asymptotically free non-abelian gauge theories, is also briefly discussed.

  2. Electromagnetic field exposure dosimeter. Final report, September 1992-May 1993

    SciTech Connect

    Feaga, A.C.; Hilliard, M.P.; Link, R.

    1994-07-28

    The growing concern about adverse health effects caused by electromagnetic radiation prompted the ideas for this dosimeter. Data have been presented that link prolonged exposure to electromagnetic radiation from power lines to leukemia and some types of cancer. At present, though, there is a lack of recording instrumentation to measure the prolonged exposure of an individual; thus, it is not possible to correlate properly the amount of exposure or dose to health effects. With the recent advances in small, low-power devices, a small measuring device can be developed. Once this is built, a large data base can be obtained to help correlate electromagnetic field exposure to health conditions. The objective of this project is to develop an instrument which can measure electromagnetic fields over a prolonged period of time. The instrument would be small, say about the size of a radio Walkman, and would be worn throughout the day while taking data, as the individual goes about normal activities. A PC would be used to retrieve the data from the instrument at the end of the day. The dosimeter comprises a triaxial ferrite-loaded coil sensor, a set of amplifiers and filters, analog-to-digital converters, a microcontroller, and random access data memory. The signals from the sensor are filtered into three frequency ranges: one to measure 60-Hz exposure and two harmonics, another to measure high-energy pulsed energy, and a third frequency range to record the activity level of the individual. The signals from the filters are digitized and read into a microcontroller. The microcontroller performs a few calculations and controls the flow of the data to either random access memory or to a computer. A computer is used to retrieve the data from the dosimeter, and can store and display the measured data.

  3. Duality and integrability: Electromagnetism, linearized gravity, and massless higher spin gauge fields as bi-Hamiltonian systems

    SciTech Connect

    Barnich, Glenn; Troessaert, Cedric

    2009-04-15

    In the reduced phase space of electromagnetism, the generator of duality rotations in the usual Poisson bracket is shown to generate Maxwell's equations in a second, much simpler Poisson bracket. This gives rise to a hierarchy of bi-Hamiltonian evolution equations in the standard way. The result can be extended to linearized Yang-Mills theory, linearized gravity, and massless higher spin gauge fields.

  4. Electric-field-induced rotation of Brownian metal nanowires.

    PubMed

    Arcenegui, Juan J; García-Sánchez, Pablo; Morgan, Hywel; Ramos, Antonio

    2013-09-01

    We describe the physical mechanism responsible for the rotation of Brownian metal nanowires suspended in an electrolyte exposed to a rotating electric field. The electric field interacts with the induced charge in the electrical double layer at the metal-electrolyte interface, causing rotation due to the torque on the induced dipole and to the induced-charge electro-osmotic flow around the particle. Experiments demonstrate that the primary driving mechanism is the former of these two. Our analysis contrasts with previous work describing the electrical manipulation of metallic particles with electric fields, which neglected the electrical double layer. Theoretical values for the rotation speed are calculated and good agreement with experiments is found.

  5. Which electromagnetic equations apply in rotating coordinates. [frame transformations in relativity

    NASA Technical Reports Server (NTRS)

    Webster, D. L.; Whitten, R. C.

    1973-01-01

    It was discovered some years ago by Schiff that two equations for fields in vacuum do not carry over without change from an inertial frame to a frame with rotating axes of space coordinates, even for a region with all velocities much lower than the speed of light. However, the belief that all four of the field equations are invariant under such conditions is still prevalent and causes misconceptions in physical applications, including astrophysical and geophysical ones. The purpose of the present paper is therefore to call attention to Schiff's discovery, discussing its basis and its extension to fields in material media, and to interpret the additional terms that must be added to the equations in order to obtain valid transformations to rotating axes of coordinates.

  6. Rotating-Disk-Based Hybridized Electromagnetic-Triboelectric Nanogenerator for Sustainably Powering Wireless Traffic Volume Sensors.

    PubMed

    Zhang, Binbin; Chen, Jun; Jin, Long; Deng, Weili; Zhang, Lei; Zhang, Haitao; Zhu, Minhao; Yang, Weiqing; Wang, Zhong Lin

    2016-06-28

    Wireless traffic volume detectors play a critical role for measuring the traffic-flow in a real-time for current Intelligent Traffic System. However, as a battery-operated electronic device, regularly replacing battery remains a great challenge, especially in the remote area and wide distribution. Here, we report a self-powered active wireless traffic volume sensor by using a rotating-disk-based hybridized nanogenerator of triboelectric nanogenerator and electromagnetic generator as the sustainable power source. Operated at a rotating rate of 1000 rpm, the device delivered an output power of 17.5 mW, corresponding to a volume power density of 55.7 W/m(3) (Pd = P/V, see Supporting Information for detailed calculation) at a loading resistance of 700 Ω. The hybridized nanogenerator was demonstrated to effectively harvest energy from wind generated by a moving vehicle through the tunnel. And the delivered power is capable of triggering a counter via a wireless transmitter for real-time monitoring the traffic volume in the tunnel. This study further expands the applications of triboelectric nanogenerators for high-performance ambient mechanical energy harvesting and as sustainable power sources for driving wireless traffic volume sensors.

  7. Plasma Rotation Control Experiment in a Strongly Diverging Magnetic Field

    NASA Astrophysics Data System (ADS)

    Terasaka, Kenichiro; Furuta, Kanshi; Yoshimura, Shinji; Aramaki, Mitsutoshi; Tanaka, Masayoshi Y.

    2016-10-01

    It has been recognized that the plasma rotation affects the plasma flow structure along the magnetic field line. However, the effect of plasma rotation on structure formation in a strongly diverging magnetic field with magnetized electrons and unmagnetized ions has not been fully understood, so far. Understanding the flow structure formation in an ion-unmagnetized plasma is essential to control ion streamline detachment from the magnetic field line and also necessary to study the astrophysical phenomena in laboratory. In order to clarify the effect of plasma rotation in a diverging magnetic field, we have performed the plasma rotation control experiment in the HYPER-II device at Kyushu Univ., Japan. A set of cylindrical electrode was utilized to control the radial electric field, and the profile of azimuthal E × B rotation has been changed. We present the experimental results on the electron density pileup and the flow reversal appeared in the rotating plasma. This study was supported by JSPS KAKENHI Grant Number 16K05633.

  8. Instability-driven electromagnetic fields in coronal plasmas

    SciTech Connect

    Manuel, M. J.-E.; Li, C. K.; Seguin, F. H.; Sinenian, N.; Frenje, J. A.; Casey, D. T.; Petrasso, R. D.; Hager, J. D.; Betti, R.; Hu, S. X.; Delettrez, J.; Meyerhofer, D. D.

    2013-04-15

    Filamentary electromagnetic fields previously observed in the coronae of laser-driven spherical targets [F. H. S eguin et al., Phys. Plasma. 19, 012701 (2012)] have been further investigated in laser irradiated plastic foils. Face-on proton-radiography provides an axial view of these filaments and shows coherent cellular structure regardless of initial foil-surface conditions. The observed cellular fields are shown to have an approximately constant scale size of 210 lm throughout the plasma evolution. A discussion of possible field-generation mechanisms is provided and it is demonstrated that the likely source of the cellular field structure is the magnetothermal instability. Using predicted temperature and density profiles, the fastest growing modes of this instability were found to be slowly varying in time and consistent with the observed cellular size.

  9. Instability-driven electromagnetic fields in coronal plasmas

    DOE PAGES

    Manuel, M. J.-E.; Li, C. K.; Seguin, F. H.; ...

    2013-04-15

    Filamentary electromagnetic fields previously observed in the coronae of laser-driven spherical targets [F. H. S eguin et al., Phys. Plasma. 19, 012701 (2012)] have been further investigated in laser irradiated plastic foils. Face-on proton-radiography provides an axial view of these filaments and shows coherent cellular structure regardless of initial foil-surface conditions. The observed cellular fields are shown to have an approximately constant scale size of 210 lm throughout the plasma evolution. A discussion of possible field-generation mechanisms is provided and it is demonstrated that the likely source of the cellular field structure is the magnetothermal instability. Using predicted temperature andmore » density profiles, the fastest growing modes of this instability were found to be slowly varying in time and consistent with the observed cellular size.« less

  10. Human disease resulting from exposure to electromagnetic fields.

    PubMed

    Carpenter, David O

    2013-01-01

    Electromagnetic fields (EMFs) include everything from cosmic rays through visible light to the electric and magnetic fields associated with electricity. While the high frequency fields have sufficient energy to cause cancer, the question of whether there are human health hazards associated with communication radiofrequency (RF) EMFs and those associated with use of electricity remains controversial. The issue is more important than ever given the rapid increase in the use of cell phones and other wireless devices. This review summarizes the evidence stating that excessive exposure to magnetic fields from power lines and other sources of electric current increases the risk of development of some cancers and neurodegenerative diseases, and that excessive exposure to RF radiation increases risk of cancer, male infertility, and neurobehavioral abnormalities. The relative impact of various sources of exposure, the great range of standards for EMF exposure, and the costs of doing nothing are also discussed.

  11. ELECTRON HOLOGRAPHY OF ELECTROMAGNETIC FIELDS - RECENT THEORETICAL ADVANCES.

    SciTech Connect

    BELEGGIA,M.; POZZI, G.; TONOMURA, A.

    2007-01-01

    It has been shown in this work that the Fourier space approach can be fruitfully applied to the calculation of the fields and the associated electron optical phase shift of several magnetic and electrostatic structures, like superconducting vortices in conventional and high-T{sub c} superconductors, reverse biased p-n junctions, magnetic domains and nanoparticles. In all these cases, this novel approach has led to unexpected but extremely interesting results, very often expressed in analytical form, which allow the quantitative and reliable interpretation of the experimental data collected by means of electron holography or of more conventional Lorentz microscopy techniques. Moreover, it is worth recalling that whenever long-range electromagnetic fields are involved, a physical model of the object under investigation is necessary in order to take into account correctly the perturbation of the reference wave induced by the tail of the field protruding into the vacuum. For these reasons, we believe that the Fourier space approach for phase computations we have introduced and discussed in this chapter will represent an invaluable tool for the investigation of electromagnetic fields at the meso- and nano-scale.

  12. A review on Electromagnetic fields (EMFs) and the reproductive system.

    PubMed

    Asghari, Ali; Khaki, Amir Afshin; Rajabzadeh, Asghar; Khaki, Arash

    2016-07-01

    Environmental factors, such as electromagnetic waves, induce biological and genetic effects. One of the most important physiological systems involved with electromagnetic fields (EMFs) is the genital system. This paper reviews the effects of EMFs on human reproductive organs, female animals, fetus development and the importance of two types of natural antioxidants, i.e., vitamin E and fennel. The studies presented in this review referred to the effects of different exposures to EMFs on the reproductive system, and we tried to show the role of natural antioxidants in reducing the effects of the exposures. Many studies have been done on the effects of ionizing and non-ionizing electromagnetic waves on the cell line of spermatogenesis, sexual hormones, and the structure of the testes. Also, about the hormonal cycle, folliculogenesis and female infertility related to EMF have been given more consideration. In particular, attention is directed to pregnant women due to the importance of their fetuses. However, in addition to the studies conducted on animals, further epidemiological research should be conducted.

  13. A review on Electromagnetic fields (EMFs) and the reproductive system

    PubMed Central

    Asghari, Ali; Khaki, Amir Afshin; Rajabzadeh, Asghar; Khaki, Arash

    2016-01-01

    Environmental factors, such as electromagnetic waves, induce biological and genetic effects. One of the most important physiological systems involved with electromagnetic fields (EMFs) is the genital system. This paper reviews the effects of EMFs on human reproductive organs, female animals, fetus development and the importance of two types of natural antioxidants, i.e., vitamin E and fennel. The studies presented in this review referred to the effects of different exposures to EMFs on the reproductive system, and we tried to show the role of natural antioxidants in reducing the effects of the exposures. Many studies have been done on the effects of ionizing and non-ionizing electromagnetic waves on the cell line of spermatogenesis, sexual hormones, and the structure of the testes. Also, about the hormonal cycle, folliculogenesis and female infertility related to EMF have been given more consideration. In particular, attention is directed to pregnant women due to the importance of their fetuses. However, in addition to the studies conducted on animals, further epidemiological research should be conducted. PMID:27648194

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

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

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

  15. Above-threshold ionization in two electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Bardfield, Rina Shoshana

    1997-11-01

    Above-threshold ionization (ATI) is a process in which a target atom absorbs more than the minimum number of photons from an applied electromagnetic field than are required for ionization, and is characterized by several peaks in the photoelectron spectrum which are separated from each other by the energy of a single photon (Agostini et al. 1979). The experiments of interest in this work involve ATI at microwave frequencies (Gallagher 1988, Gallagher and Scholz 1989), where the frequency of the field is too low to be able to see individual peaks in the spectrum. What is seen is that, in the presence of a weak assisting field, a very large number of microwave photons are absorbed. This problem cannot be treated using standard methods, due both to the intensity of the microwave field and to the large numbers of photons absorbed. The focus of this work is on the development of new analytical techniques to examine the interaction of an atomic system with two simultaneous electromagnetic fields. Specifically, the work focuses on above-threshold ionization in combined microwave and laser fields, where the microwave field is a very strong, very low frequency field, so that standard techniques, such as perturbation theory, do not apply. The work is based on two theoretical methods especially designed for use in intense field problems. These are the Strong Field Approximation (SFA) (Reiss 1980, 1992, 1996), which describes the ionization of an atom by an intense field in which the detached electron remains free in the field after ionization occurs, and the Momentum Translation Approximation (MTA) (Reiss 1970a, 1970b, 1989), which describes the dressing of a bound atomic state by a strong field in which the field can alter the state of the electron without necessarily causing transitions. The laser field, which is much weaker, is treated by traditional techniques. The theory is developed in general terms using S-matrix methods, with particular cases being modeled using

  16. An Optimization of Pulsed ElectroMagnetic Fields Study

    NASA Technical Reports Server (NTRS)

    Goodwin, Thomas J.

    2006-01-01

    To date, in our research we have focused on the use of normal human neuronal progenitor (NHNP) cells because of their importance in human nervous system regeneration, development and maintenance, but we have developed 2-D and 3-D bioreactors that can accommodate any cell line. In this Project, we will include the use of tissues important for physiological regeneration: Human osteoblasts or chondrocytes, and vascular cells. Our initial results with the NHNP cells were quite startling using extremely low-level electromagnetic fields (5 microtesla at 10Hz; 6mA). The low-amplitude, rapidly time-varying electromagnetic fields exert a very potent effect on the proliferation, morphology, and gene expression of the cells in culture, both in standard 2-dimensional culture plates as well as cells organized into 3-dimensional tissue-like assemblies (TLAs) in a 3D bioreactor. We have replicated our preliminary results many, many times, have analyzed the gene expression using gene arrays (followed by Luminex analysis for protein production), and have monitored cell proliferation, orientation, morphology, and glucose metabolism, and we are confident that we have a stable and reliable model to study the control of high-level cellular processes by application of low-amplitude, time varying electromagnetic fields (TVEMF) (1, 2). In additional studies at the University of Michigan, we have been able to generate functional in vitro engineered mammalian skeletal muscle, and have employed nerve-muscle co-culture techniques to promote axonal sprouting. We believe that nearly all tissues, in particular, neural, are susceptible to the influences of low-level TVEMF.

  17. Difficulties in applying numerical simulations to an evaluation of occupational hazards caused by electromagnetic fields.

    PubMed

    Zradziński, Patryk

    2015-01-01

    Due to the various physical mechanisms of interaction between a worker's body and the electromagnetic field at various frequencies, the principles of numerical simulations have been discussed for three areas of worker exposure: to low frequency magnetic field, to low and intermediate frequency electric field and to radiofrequency electromagnetic field. This paper presents the identified difficulties in applying numerical simulations to evaluate physical estimators of direct and indirect effects of exposure to electromagnetic fields at various frequencies. Exposure of workers operating a plastic sealer have been taken as an example scenario of electromagnetic field exposure at the workplace for discussion of those difficulties in applying numerical simulations. The following difficulties in reliable numerical simulations of workers' exposure to the electromagnetic field have been considered: workers' body models (posture, dimensions, shape and grounding conditions), working environment models (objects most influencing electromagnetic field distribution) and an analysis of parameters for which exposure limitations are specified in international guidelines and standards.

  18. Difficulties in applying numerical simulations to an evaluation of occupational hazards caused by electromagnetic fields

    PubMed Central

    Zradziński, Patryk

    2015-01-01

    Due to the various physical mechanisms of interaction between a worker's body and the electromagnetic field at various frequencies, the principles of numerical simulations have been discussed for three areas of worker exposure: to low frequency magnetic field, to low and intermediate frequency electric field and to radiofrequency electromagnetic field. This paper presents the identified difficulties in applying numerical simulations to evaluate physical estimators of direct and indirect effects of exposure to electromagnetic fields at various frequencies. Exposure of workers operating a plastic sealer have been taken as an example scenario of electromagnetic field exposure at the workplace for discussion of those difficulties in applying numerical simulations. The following difficulties in reliable numerical simulations of workers’ exposure to the electromagnetic field have been considered: workers’ body models (posture, dimensions, shape and grounding conditions), working environment models (objects most influencing electromagnetic field distribution) and an analysis of parameters for which exposure limitations are specified in international guidelines and standards. PMID:26323781

  19. Accuracy Improvement in Magnetic Field Modeling for an Axisymmetric Electromagnet

    NASA Technical Reports Server (NTRS)

    Ilin, Andrew V.; Chang-Diaz, Franklin R.; Gurieva, Yana L.; Il,in, Valery P.

    2000-01-01

    This paper examines the accuracy and calculation speed for the magnetic field computation in an axisymmetric electromagnet. Different numerical techniques, based on an adaptive nonuniform grid, high order finite difference approximations, and semi-analitical calculation of boundary conditions are considered. These techniques are being applied to the modeling of the Variable Specific Impulse Magnetoplasma Rocket. For high-accuracy calculations, a fourth-order scheme offers dramatic advantages over a second order scheme. For complex physical configurations of interest in plasma propulsion, a second-order scheme with nonuniform mesh gives the best results. Also, the relative advantages of various methods are described when the speed of computation is an important consideration.

  20. Healing of Chronic Wounds through Systemic Effects of Electromagnetic Fields

    NASA Astrophysics Data System (ADS)

    Cañedo, L.; Trigos, I.; García-Cantú, R.; Godina-Nava, J. J.; Serrano, G.

    2002-08-01

    Extremely low frequency electromagnetic fields (ELF) were configured to interact with peripheral blood mononuclear cells (PBMC). These ELF were applied in the arm to five patients with chronic wounds resistant to medical and surgical treatment. Wound healing began in all patients during the first two weeks after ELF exposure permiting their previously unresponsive chronic wounds to function as internal controls. All lesions were cured or healed >70% in less than four months. Systemic effects were explained by ELF activation of PBMC and their transportation through the blood to the affected site. This therapy is effective in selected patients with chronic wounds.

  1. On Acceptable Exposures to Short Pulses of Electromagnetic Fields

    DTIC Science & Technology

    2015-09-01

    standards and other research on the safety to humans of short pulses of electromagnetic radiation . Special attention is paid to a ten nanosecond...pulses of electromagnetic radiation have been considered. Considerations for implanted medical devices and implanted metal objects and the like are...of Electromagnetic Precursors,” Proceedings of the International Conference on Electromagnetics in Advanced Applications, Torino, Italy, September

  2. Basics of quantum field theory of electromagnetic interaction processes in single-layer graphene

    NASA Astrophysics Data System (ADS)

    Hieu Nguyen, Van

    2016-09-01

    The content of this work is the study of electromagnetic interaction in single-layer graphene by means of the perturbation theory. The interaction of electromagnetic field with Dirac fermions in single-layer graphene has a peculiarity: Dirac fermions in graphene interact not only with the electromagnetic wave propagating within the graphene sheet, but also with electromagnetic field propagating from a location outside the graphene sheet and illuminating this sheet. The interaction Hamiltonian of the system comprising electromagnetic field and Dirac fermions fields contains the limits at graphene plane of electromagnetic field vector and scalar potentials which can be shortly called boundary electromagnetic field. The study of S-matrix requires knowing the limits at graphene plane of 2-point Green functions of electromagnetic field which also can be shortly called boundary 2-point Green functions of electromagnetic field. As the first example of the application of perturbation theory, the second order terms in the perturbative expansions of boundary 2-point Green functions of electromagnetic field as well as of 2-point Green functions of Dirac fermion fields are explicitly derived. Further extension of the application of perturbation theory is also discussed.

  3. Surface chirality induced by rotational electrodeposition in magnetic fields

    PubMed Central

    Mogi, Iwao; Morimoto, Ryoichi; Aogaki, Ryoichi; Watanabe, Kazuo

    2013-01-01

    The surfaces of minerals could serve important catalytic roles in the prebiotic syntheses of organic molecules, such as amino acids. Thus, the surface chirality is responsible for the asymmetric syntheses of biomolecules. Here, we show induction of the surface chirality of copper metal film by electrodeposition via electrochemical cell rotation in magnetic fields. Such copper film electrodes exhibit chiral behaviour in the electrochemical reaction of alanine enantiomers, and the rotating direction allows control of the chiral sign. These findings are discussed in connection with the asymmetric influence of the system rotation on the magnetohydrodynamic micro-vortices around the electrode surfaces. PMID:23999254

  4. Analyzing Extragalactic Magnetic Fields Using Faraday Rotation Measure Synthesis

    NASA Astrophysics Data System (ADS)

    Pare, Dylan; Wang, Q. Daniel; Kamieneski, Patrick; Sullivan, Kendall

    2017-01-01

    Extragalactic magnetic fields are a poorly understood element of galaxies that are likely to play an important role in galaxy formation and evolution. Until recently, however, there was no way to observe these fields to a high level of detail, making it difficult to map the spatial distribution of these fields to any high degree of accuracy. Fortunately, a new technique known as Faraday Rotation Measure Synthesis allows for a more precise analysis of galactic magnetism. This technique uses the observed Faraday rotation of polarized emission from background sources to map the magnetic field of a foreground galaxy. This Faraday rotation occurs when the polarized emission encounters ionized, magnetized gas within the galaxy, causing the emission to be rotated by an amount proportional the magnetic field subjected to the ionized gas. Working as part of CHANG-ES (Continuum HAlos in Nearby Galaxies - an EVLA Survey), we have applied this technique in order to learn about the distribution of magnetic fields in the disks and halos of edge-on spiral galaxies. We will present maps of the galactic magnetic fields of CHANG-ES galaxies using this technique, indicating the potential of this technique in successfully mapping these distant fields.

  5. Electromagnetic field tapering using all-dielectric gradient index materials

    PubMed Central

    Yi, Jianjia; Piau, Gérard-Pascal; de Lustrac, André; Burokur, Shah Nawaz

    2016-01-01

    The concept of transformation optics (TO) is applied to control the flow of electromagnetic fields between two sections of different dimensions through a tapering device. The broadband performance of the field taper is numerically and experimentally validated. The taper device presents a graded permittivity profile and is fabricated through three-dimensional (3D) polyjet printing technology using low-cost all-dielectric materials. Calculated and measured near-field mappings are presented in order to validate the proposed taper. A good qualitative agreement is obtained between full-wave simulations and experimental tests. Such all-dielectric taper paves the way to novel types of microwave devices that can be easily fabricated through low-cost additive manufacturing processes. PMID:27464989

  6. Conserved currents for electromagnetic fields in the Kerr spacetime

    NASA Astrophysics Data System (ADS)

    Grant, Alexander; Flanagan, Eanna

    2017-01-01

    For any classical linear Lagrangian field theory, the symplectic product provides a conserved current that is bilinear on the space of solutions. Given a linear mapping from the space of solutions into itself, a ``symmetry operator'', one can therefore generate quadratic conserved currents for any linear classical field theory. We apply this procedure to the case of electromagnetism on a Kerr background, showing that this procedure can generate the conserved currents given by Andersson, Bäckdahl, and Blue, as well as two new conserved currents. These currents reduce to the sum of (positive powers of) the Carter constants of the photons in the geometric optics limit, and generalize the current for scalar fields discovered by Carter. We furthermore show that the fluxes of these new currents through null infinity and the horizon are finite.

  7. Electromagnetic field tapering using all-dielectric gradient index materials

    NASA Astrophysics Data System (ADS)

    Yi, Jianjia; Piau, Gérard-Pascal; de Lustrac, André; Burokur, Shah Nawaz

    2016-07-01

    The concept of transformation optics (TO) is applied to control the flow of electromagnetic fields between two sections of different dimensions through a tapering device. The broadband performance of the field taper is numerically and experimentally validated. The taper device presents a graded permittivity profile and is fabricated through three-dimensional (3D) polyjet printing technology using low-cost all-dielectric materials. Calculated and measured near-field mappings are presented in order to validate the proposed taper. A good qualitative agreement is obtained between full-wave simulations and experimental tests. Such all-dielectric taper paves the way to novel types of microwave devices that can be easily fabricated through low-cost additive manufacturing processes.

  8. Electromagnetic field tapering using all-dielectric gradient index materials.

    PubMed

    Yi, Jianjia; Piau, Gérard-Pascal; de Lustrac, André; Burokur, Shah Nawaz

    2016-07-28

    The concept of transformation optics (TO) is applied to control the flow of electromagnetic fields between two sections of different dimensions through a tapering device. The broadband performance of the field taper is numerically and experimentally validated. The taper device presents a graded permittivity profile and is fabricated through three-dimensional (3D) polyjet printing technology using low-cost all-dielectric materials. Calculated and measured near-field mappings are presented in order to validate the proposed taper. A good qualitative agreement is obtained between full-wave simulations and experimental tests. Such all-dielectric taper paves the way to novel types of microwave devices that can be easily fabricated through low-cost additive manufacturing processes.

  9. Time dependent electromagnetic fields and 4-dimensional Stokes' theorem

    NASA Astrophysics Data System (ADS)

    Andosca, Ryan; Singleton, Douglas

    2016-11-01

    Stokes' theorem is central to many aspects of physics—electromagnetism, the Aharonov-Bohm effect, and Wilson loops to name a few. However, the pedagogical examples and research work almost exclusively focus on situations where the fields are time-independent so that one need only deal with purely spatial line integrals (e.g., ∮ A . d x ) and purely spatial area integrals (e.g., ∫ ( ∇ × A ) . d a = ∫ B . d a ). Here, we address this gap by giving some explicit examples of how Stokes' theorem plays out with time-dependent fields in a full 4-dimensional spacetime context. We also discuss some unusual features of Stokes' theorem with time-dependent fields related to gauge transformations and non-simply connected topology.

  10. Chiral states of electromagnetic fields originated from ferrite-based microwave vortices

    SciTech Connect

    Sigalov, M.; Kamenetskii, E. O.; Shavit, R.

    2008-12-01

    Electromagnetic vortices in a microwave cavity with an inserted piece of a magnetized ferrite appear due to the time-reversal symmetry breaking effect. We reveal numerically that the Poynting-vector vortices are possible in open resonant microwave structures with ferrite inclusions. We demonstrate a pair of resonances which have opposite vortex rotations at the same direction of time given by the direction of the magnetization precession. There are two coalescent resonances with different chirality. We show that the structures of the radiating near and far fields are intimately related to the ferrite-induced topological singularities. The observed far-field polarization structures represent a doublet of chiral vortices in space originated from a doublet of resonant chiral states in a patch resonator with an enclosed ferrite disk.

  11. Weak scattering of scalar and electromagnetic random fields

    NASA Astrophysics Data System (ADS)

    Tong, Zhisong

    This dissertation encompasses several studies relating to the theory of weak potential scattering of scalar and electromagnetic random, wide-sense statistically stationary fields from various types of deterministic or random linear media. The proposed theory is largely based on the first Born approximation for potential scattering and on the angular spectrum representation of fields. The main focus of the scalar counterpart of the theory is made on calculation of the second-order statistics of scattered light fields in cases when the scattering medium consists of several types of discrete particles with deterministic or random potentials. It is shown that the knowledge of the correlation properties for the particles of the same and different types, described with the newly introduced pair-scattering matrix, is crucial for determining the spectral and coherence states of the scattered radiation. The approach based on the pair-scattering matrix is then used for solving an inverse problem of determining the location of an "alien" particle within the scattering collection of "normal" particles, from several measurements of the spectral density of scattered light. Weak scalar scattering of light from a particulate medium in the presence of optical turbulence existing between the scattering centers is then approached using the combination of the Born's theory for treating the light interaction with discrete particles and the Rytov's theory for light propagation in extended turbulent medium. It is demonstrated how the statistics of scattered radiation depend on scattering potentials of particles and the power spectra of the refractive index fluctuations of turbulence. This theory is of utmost importance for applications involving atmospheric and oceanic light transmission. The second part of the dissertation includes the theoretical procedure developed for predicting the second-order statistics of the electromagnetic random fields, such as polarization and linear momentum

  12. Robust multiscale field-only formulation of electromagnetic scattering

    NASA Astrophysics Data System (ADS)

    Sun, Qiang; Klaseboer, Evert; Chan, Derek Y. C.

    2017-01-01

    We present a boundary integral formulation of electromagnetic scattering by homogeneous bodies that are characterized by linear constitutive equations in the frequency domain. By working with the Cartesian components of the electric E and magnetic H fields and with the scalar functions (r .E ) and (r .H ) where r is a position vector, the problem can be cast as having to solve a set of scalar Helmholtz equations for the field components that are coupled by the usual electromagnetic boundary conditions at material boundaries. This facilitates a direct solution for the surface values of E and H rather than having to work with surface currents or surface charge densities as intermediate quantities in existing methods. Consequently, our formulation is free of the well-known numerical instability that occurs in the zero-frequency or long-wavelength limit in traditional surface integral solutions of Maxwell's equations and our numerical results converge uniformly to the static results in the long-wavelength limit. Furthermore, we use a formulation of the scalar Helmholtz equation that is expressed as classically convergent integrals and does not require the evaluation of principal value integrals or any knowledge of the solid angle. Therefore, standard quadrature and higher order surface elements can readily be used to improve numerical precision for the same number of degrees of freedom. In addition, near and far field values can be calculated with equal precision, and multiscale problems in which the scatterers possess characteristic length scales that are both large and small relative to the wavelength can be easily accommodated. From this we obtain results for the scattering and transmission of electromagnetic waves at dielectric boundaries that are valid for any ratio of the local surface curvature to the wave number. This is a generalization of the familiar Fresnel formula and Snell's law, valid at planar dielectric boundaries, for the scattering and transmission

  13. Mode- and plasma rotation in a resistive shell reversed-field pinch

    NASA Astrophysics Data System (ADS)

    Malmberg, J.-A.; Brzozowski, J.; Brunsell, P. R.; Cecconello, M.; Drake, J. R.

    2004-02-01

    Mode rotation studies in a resistive shell reversed-field pinch, EXTRAP T2R [P. R. Brunsell et al., Plasma Phys. Control. Fusion 43, 1 (2001)] are presented. The phase relations and nonlinear coupling of the resonant modes are characterized and compared with that expected from modeling based on the hypothesis that mode dynamics can be described by a quasi stationary force balance including electromagnetic and viscous forces. Both m=0 and m=1 resonant modes are studied. The m=1 modes have rotation velocities corresponding to the plasma flow velocity (20-60 km/s) in the core region. The rotation velocity decreases towards the end of the discharge, although the plasma flow velocity does not decrease. A rotating phase locked m=1 structure is observed with a velocity of about 60 km/s. The m=0 modes accelerate throughout the discharges and reach velocities as high as 150-250 km/s. The observed m=0 phase locking is consistent with theory for certain conditions, but there are several conditions when the dynamics are not described. This is not unexpected because the assumption of quasi stationarity for the mode spectra is not fulfilled for many conditions. Localized m=0 perturbations are formed in correlation with highly transient discrete dynamo events. These perturbations form at the location of the m=1 phase locked structure, but rotate with a different velocity as they spread out in the toroidal direction.

  14. Pulsed Electromagnetic Field Assisted in vitro Electroporation: A Pilot Study

    NASA Astrophysics Data System (ADS)

    Novickij, Vitalij; Grainys, Audrius; Lastauskienė, Eglė; Kananavičiūtė, Rūta; Pamedytytė, Dovilė; Kalėdienė, Lilija; Novickij, Jurij; Miklavčič, Damijan

    2016-09-01

    Electroporation is a phenomenon occurring due to exposure of cells to Pulsed Electric Fields (PEF) which leads to increase of membrane permeability. Electroporation is used in medicine, biotechnology, and food processing. Recently, as an alternative to electroporation by PEF, Pulsed ElectroMagnetic Fields (PEMF) application causing similar biological effects was suggested. Since induced electric field in PEMF however is 2–3 magnitudes lower than in PEF electroporation, the membrane permeabilization mechanism remains hypothetical. We have designed pilot experiments where Saccharomyces cerevisiae and Candida lusitaniae cells were subjected to single 100–250 μs electrical pulse of 800 V with and without concomitant delivery of magnetic pulse (3, 6 and 9 T). As expected, after the PEF pulses only the number of Propidium Iodide (PI) fluorescent cells has increased, indicative of membrane permeabilization. We further show that single sub-millisecond magnetic field pulse did not cause detectable poration of yeast. Concomitant exposure of cells to pulsed electric (PEF) and magnetic field (PMF) however resulted in the increased number PI fluorescent cells and reduced viability. Our results show increased membrane permeability by PEF when combined with magnetic field pulse, which can explain electroporation at considerably lower electric field strengths induced by PEMF compared to classical electroporation.

  15. Pulsed Electromagnetic Field Assisted in vitro Electroporation: A Pilot Study

    PubMed Central

    Novickij, Vitalij; Grainys, Audrius; Lastauskienė, Eglė; Kananavičiūtė, Rūta; Pamedytytė, Dovilė; Kalėdienė, Lilija; Novickij, Jurij; Miklavčič, Damijan

    2016-01-01

    Electroporation is a phenomenon occurring due to exposure of cells to Pulsed Electric Fields (PEF) which leads to increase of membrane permeability. Electroporation is used in medicine, biotechnology, and food processing. Recently, as an alternative to electroporation by PEF, Pulsed ElectroMagnetic Fields (PEMF) application causing similar biological effects was suggested. Since induced electric field in PEMF however is 2–3 magnitudes lower than in PEF electroporation, the membrane permeabilization mechanism remains hypothetical. We have designed pilot experiments where Saccharomyces cerevisiae and Candida lusitaniae cells were subjected to single 100–250 μs electrical pulse of 800 V with and without concomitant delivery of magnetic pulse (3, 6 and 9 T). As expected, after the PEF pulses only the number of Propidium Iodide (PI) fluorescent cells has increased, indicative of membrane permeabilization. We further show that single sub-millisecond magnetic field pulse did not cause detectable poration of yeast. Concomitant exposure of cells to pulsed electric (PEF) and magnetic field (PMF) however resulted in the increased number PI fluorescent cells and reduced viability. Our results show increased membrane permeability by PEF when combined with magnetic field pulse, which can explain electroporation at considerably lower electric field strengths induced by PEMF compared to classical electroporation. PMID:27634482

  16. Radio frequency electromagnetic fields: cancer, mutagenesis, and genotoxicity.

    PubMed

    Heynick, Louis N; Johnston, Sheila A; Mason, Patrick A

    2003-01-01

    We present critiques of epidemiologic studies and experimental investigations, published mostly in peer-reviewed journals, on cancer and related effects from exposure to nonionizing electromagnetic fields in the nominal frequency range of 3 kHz to 300 GHz of interest to Subcommittee 4 (SC4) of the International Committee on Electromagnetic Safety (ICES). The major topics discussed are presented under the headings Epidemiologic and Other Findings on Human Exposure, Mammals Exposed In Vivo, Mammalian Live Tissues and Cell Preparations Exposed In Vitro, and Mutagenesis and Genotoxicity in Microorganisms and Fruit Flies. Under each major topic, we present minireviews of papers on various specific endpoints investigated. The section on Epidemiologic and Other Findings on Human Exposure is divided into two subsections, the first on possible carcinogenic effects of exposure from emitters not in physical contact with the populations studied, for example, transmitting antennas and other devices. Discussed in the second subsection are studies of postulated carcinogenic effects from use of mobile phones, with prominence given to brain tumors from use of cellular and cordless telephones in direct physical contact with an ear of each subject. In both subsections, some investigations yielded positive findings, others had negative findings, including papers directed toward experimentally verifying positive findings, and both were reported in a few instances. Further research on various important aspects may resolve such differences. Overall, however, the preponderance of published epidemiologic and experimental findings do not support the supposition that in vivo or in vitro exposures to such fields are carcinogenic.

  17. Quantum Mechanics Action of ELF Electromagnetic Fields on Living Organisms

    NASA Astrophysics Data System (ADS)

    Godina-Nava, J. J.

    2010-10-01

    There is presently an intense discussion if extremely low frequency electromagnetic field (ELF-EMF) exposure has consequences for human health. This include exposure to structures and appliances from this range of frequency in the electromagnetic (EM) spectrum. Biological effects of such exposures have been noted frequently, although the implications for specific health effects is not that clear. The basic interactions mechanisms between such fields and living matter is unknown. Numerous hypotheses have been suggested, although none is convincingly supported by experimental data. Various cellular components, processes, and systems can be affected by EMF exposure. Since it is unlikely that EMF can induce DNA damage directly, most studies have examined EMF effects on the cell membrane level, general and specific gene expression, and signal transduction pathways. Even more, a large number of studies have been performed regarding cell proliferation, cell cycle regulation, cell differentiation, metabolism, and various physiological characteristics of cells. The aim of this letter is present the hypothesis of a possible quantum mechanic effect generated by the exposure of ELF EMF, an event which is compatible with the multitude of effects observed after exposure. Based on an extensive literature review, we suggest that ELF EMF exposure is able to perform such activation restructuring the electronic level of occupancy of free radicals in molecules interacting with DNA structures.

  18. Investigations of Magnetically Enhanced RIE Reactors with Rotating Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Babaeva, Natalia Yu.; Kushner, Mark J.

    2008-10-01

    In Magnetically Enhanced Reactive Ion Etching (MERIE) reactors, a magnetic field parallel to the substrate enables higher plasma densities and control of ion energy distributions. Since it is difficult to make the B-field uniform across the wafer, the B-field is often azimuthally rotated at a few Hz to average out non-uniformities. The rotation is slow enough that the plasma is in quasi-equilibrium with the instantaneous B-field. For the pressures (10's mTorr or less) and B-fields (10's - 100's G) of interest, electrons are magnetized whereas ions are usually not. The orientation and intersection of the B-field with the wafer are important, as intersecting field lines provide a low resistance path for electron current to the substrate. We report on a modeling study of plasma properties in MERIE reactors having rotating B-fields by investigating a series of quasi-steady states of B-field profiles. To resolve side-to-side variations, computations are performed in Cartesian coordinates. The model, nonPDPSIM, was improved with full tensor conductivities in the fluid portions of the code and v x B forces in the kinetic portions. Results are discussed while varying the orientation and strength of the B-field for electropositive (argon) and electronegative (Ar/CxFy, Ar/Cl2) gas mixtures.

  19. Protein detection with magnetic nanoparticles in a rotating magnetic field

    NASA Astrophysics Data System (ADS)

    Dieckhoff, Jan; Lak, Aidin; Schilling, Meinhard; Ludwig, Frank

    2014-01-01

    A detection scheme based on magnetic nanoparticle (MNP) dynamics in a rotating magnetic field for a quantitative and easy-to-perform detection of proteins is illustrated. For the measurements, a fluxgate-based setup was applied, which measures the MNP dynamics, while a rotating magnetic field is generated. The MNPs exhibit single iron oxide cores of 25 nm and 40 nm diameter, respectively, as well as a protein G functionalized shell. IgG antibodies were utilized as binding target molecules for the physical proof-of-concept. The measurement results were fitted with a theoretical model describing the magnetization dynamics in a rotating magnetic field. The established detection scheme allows quantitative determination of proteins even at a concentration lower than of the particles. The observed differences between the two MNP types are discussed on the basis of logistic functions.

  20. The Stability of Magnetized Rotating Plasmas with Superthermal Fields

    NASA Astrophysics Data System (ADS)

    Pessah, Martin E.; Psaltis, Dimitrios

    2005-08-01

    During the last decade it has become evident that the magnetorotational instability is at the heart of the enhanced angular momentum transport in weakly magnetized accretion disks around neutron stars and black holes. In this paper we investigate the local linear stability of differentially rotating, magnetized flows and the evolution of the magnetorotational instability beyond the weak-field limit. We show that, when superthermal toroidal fields are considered, the effects of both compressibility and magnetic tension forces, which are related to the curvature of toroidal field lines, should be taken fully into account. We demonstrate that the presence of a strong toroidal component in the magnetic field plays a nontrivial role. When strong fields are considered, the strength of the toroidal magnetic field not only modifies the growth rates of the unstable modes but also determines which modes are subject to instabilities. We find that, for rotating configurations with Keplerian laws, the magnetorotational instability is stabilized at low wavenumbers for toroidal Alfvén speeds exceeding the geometric mean of the sound speed and the rotational speed. For a broad range of magnetic field strengths, we also find that two additional distinct instabilities are present; they both appear as the result of coupling between the modes that become the Alfvén and the slow modes in the limit of no rotation. We discuss the significance of our findings for the stability of cold, magnetically dominated, rotating fluids and argue that, for these systems, the curvature of toroidal field lines cannot be neglected even when short-wavelength perturbations are considered. We also comment on the implications of our results for the validity of shearing box simulations in which superthermal toroidal fields are generated.

  1. Nonlinear resonance of the rotating circular plate under static loads in magnetic field

    NASA Astrophysics Data System (ADS)

    Hu, Yuda; Wang, Tong

    2015-11-01

    The rotating circular plate is widely used in mechanical engineering, meanwhile the plates are often in the electromagnetic field in modern industry with complex loads. In order to study the resonance of a rotating circular plate under static loads in magnetic field, the nonlinear vibration equation about the spinning circular plate is derived according to Hamilton principle. The algebraic expression of the initial deflection and the magneto elastic forced disturbance differential equation are obtained through the application of Galerkin integral method. By mean of modified Multiple scale method, the strongly nonlinear amplitude-frequency response equation in steady state is established. The amplitude frequency characteristic curve and the relationship curve of amplitude changing with the static loads and the excitation force of the plate are obtained according to the numerical calculation. The influence of magnetic induction intensity, the speed of rotation and the static loads on the amplitude and the nonlinear characteristics of the spinning plate are analyzed. The proposed research provides the theory reference for the research of nonlinear resonance of rotating plates in engineering.

  2. Magnetic field induced by elliptical instability in a rotating spheroid

    NASA Astrophysics Data System (ADS)

    Lacaze, L.; Herreman, W.; Le Bars, M.; Le Dizès, S.; Le Gal, P.

    2006-10-01

    The tidal or the elliptical instability of the rotating fluid flows is generated by the resonant interaction of the inertial waves. In a slightly elliptically deformed rotating sphere, the most unstable linear mode is called the spin-over mode, and is a solid body rotation versus an axis aligned with the maximum strain direction. In the non-viscous case, this instability corresponds to the median moment of the inertial instability of the solid rotating bodies. This analogy is furthermore illustrated by an elliptical top experiment, which shows the expected inviscid heteroclinic behaviour. In geophysics, the elliptical instability may appear in the molten liquid cores of the rotating planets, which are slightly deformed by the tidal gravitational effects of the close bodies. It may then participate in the general outer core dynamics and possibly the geodynamo process. In this context, Kerswell and Malkus (Kerswell, R.R. and Malkus, W.V.R., Tidal instability as the source for Io's magnetic signature. Geophys. Res. Lett., 1998, 25, 603 606) showed that the puzzling magnetic field of the Jovian satellite Io may indeed be induced by the elliptically unstable motions of its liquid core that deflect the Jupiter's magnetic field. Our magnetohydrodynamics (MHD) experiment is a toy-experiment of this geophysical situation and demonstrates for the first time the possibility of an induction of a magnetic field by the flow motions due to the elliptical instability. A full analytical calculation of the magnetic dipole induced by the spin-over is presented. Finally, exponential growths of this induced magnetic field in a slightly deformed rotating sphere filled with galinstan liquid metal are measured for different rotating rates. Their growth rates compare well with the theoretical predictions in the limit of a vanishing Lorentz force.

  3. Acceleration of adiabatic quantum dynamics in electromagnetic fields

    SciTech Connect

    Masuda, Shumpei; Nakamura, Katsuhiro

    2011-10-15

    We show a method to accelerate quantum adiabatic dynamics of wave functions under electromagnetic field (EMF) by developing the preceding theory [Masuda and Nakamura, Proc. R. Soc. London Ser. A 466, 1135 (2010)]. Treating the orbital dynamics of a charged particle in EMF, we derive the driving field which accelerates quantum adiabatic dynamics in order to obtain the final adiabatic states in any desired short time. The scheme is consolidated by describing a way to overcome possible singularities in both the additional phase and driving potential due to nodes proper to wave functions under EMF. As explicit examples, we exhibit the fast forward of adiabatic squeezing and transport of excited Landau states with nonzero angular momentum, obtaining the result consistent with the transitionless quantum driving applied to the orbital dynamics in EMF.

  4. Interaction of extremely-low-frequency electromagnetic fields with humans

    SciTech Connect

    Tenforde, T.S.

    1991-07-01

    At a macroscopic level, the effects of extremely low frequency (ELF) electromagnetic fields on humans are well understood based on fundamental physical principles, but far less is known about the nature of the interactions at a cellular or molecular level. Current evidence suggests the effects of ELF on cellular biochemistry are due to interactions with the cell membrane. Elucidation of the mechanism that underlies this transmembrane signaling is critical for a molecular-level understanding of ELF field effects. Further research is also required to clarify a possible link between ELF exposure and increased cancer risk, since estimated ELF exposure in occupational or residential settings is much lower that the levels used in laboratory studies. There is a clear need for additional epidemiological research in which qualitative dosimetry is used to characterize ELF exposure and careful attention is given to possible effects of confounding variables. 24 refs.

  5. Electromagnetic field limits set by the V-Curve.

    SciTech Connect

    Warne, Larry Kevin; Jorgenson, Roy Eberhardt; Hudson, Howard Gerald

    2014-07-01

    When emitters of electromagnetic energy are operated in the vicinity of sensitive components, the electric field at the component location must be kept below a certain level in order to prevent the component from being damaged, or in the case of electro-explosive devices, initiating. The V-Curve is a convenient way to set the electric field limit because it requires minimal information about the problem configuration. In this report we will discuss the basis for the V-Curve. We also consider deviations from the original V-Curve resulting from inductive versus capacitive antennas, increases in directivity gain for long antennas, decreases in input impedance when operating in a bounded region, and mismatches dictated by transmission line losses. In addition, we consider mitigating effects resulting from limited antenna sizes.

  6. Electromagnetic fields and the induction of DNA strand breaks.

    PubMed

    Ruiz-Gómez, Miguel J; Martínez-Morillo, Manuel

    2009-01-01

    The International Agency for Research on Cancer (IARC) has classified the extremely low-frequency (ELF) electromagnetic fields (EMF) as "possible carcinogenic" based on the reported effects. The purpose of this work is to review and compare the recent findings related to the induction of DNA strand breaks (DNA-SB) by magnetic field (MF) exposure. We found 29 studies (genotoxic and epigenetic) about the induction of DNA-SB by MF. 50% showed effect of MF and 50% showed no DNA-SB. Nevertheless, considering only genotoxic or only epigenetic studies, 37.5% and 69.2% found induction of DNA-SB by MF, respectively. In relation to these data it seems that MF could act as a co-inductor of DNA damage rather than as a genotoxic agent per se. Nevertheless, the published results, in some cases conflicting with negative findings, do not facilitate to obtain a common consensus about MF effects and biophysical interaction mechanisms.

  7. Electromagnetic plasma wave emissions from the auroral field lines

    NASA Technical Reports Server (NTRS)

    Gurnett, D. A.

    1977-01-01

    The most important types of auroral radio emissions are reviewed, both from a historical perspective as well as considering the latest results. Particular emphasis is placed on four types of electromagnetic emissions which are directly associated with the plasma on the auroral field lines. These emissions are (1) auroral hiss, (2) saucers, (3) ELF noise bands, and (4) auroral kilometric radiation. Ray tracing and radio direction finding measurements indicate that both the auroral hiss and auroral kilometric radiation are generated along the auroral field lines relatively close to the earth, at radial distances from about 2.5 to 5 R sub e. For the auroral hiss the favored mechanism appears to be amplified Cerenkov radiation. For the auroral kilometric radiation several mechanisms have been proposed, usually involving the intermediate generation of electrostatic waves by the precipitating electrons.

  8. Electromagnetic field triggered drug and chemical delivery via liposomes

    DOEpatents

    Liburdy, Robert P.

    1993-01-01

    The present invention relates to a system and to a method of delivering a drug to a preselected target body site of a patient, comprising the steps of encapsulating the chemical agent within liposomes, essentially temperature insensitive, i.e. not having a specific predetermined phase transition temperature within the specific temperature range of drug administration; administering the liposomes to the target body site; and subjecting the target body site to nonionizing electromagnetic fields in an area of the preselected target body in order to release said chemical agent from the liposomes at a temperature of between about +10 and 65.degree. C. The invention further relates to the use of said liposomes to bind to the surface of or to enter target tissue or an organ in a living system, and, when subjected to a nonionizing field, to release a drug from the liposomes into the target site.

  9. Near-field electromagnetic theory for thin solar cells.

    PubMed

    Niv, A; Gharghi, M; Gladden, C; Miller, O D; Zhang, X

    2012-09-28

    Current methods for evaluating solar cell efficiencies cannot be applied to low-dimensional structures where phenomena from the realm of near-field optics prevail. We present a theoretical approach to analyze solar cell performance by allowing rigorous electromagnetic calculations of the emission rate using the fluctuation-dissipation theorem. Our approach shows the direct quantification of the voltage, current, and efficiency of low-dimensional solar cells. This approach is demonstrated by calculating the voltage and the efficiency of a GaAs slab solar cell for thicknesses from several microns down to a few nanometers. This example highlights the ability of the proposed approach to capture the role of optical near-field effects in solar cell performance.

  10. The dielectric response to the magnetic field of electromagnetic radiation

    NASA Astrophysics Data System (ADS)

    Mukherjee, Shouvik; Mukhopadhyay, Sourabh; Datta, Prasanta Kumar

    2017-04-01

    Light–matter interaction in transparent dielectrics is revisited, including the magnetic force on bound charges in the Lorentz oscillator model. The parameter ranges of incident radiation and the medium on which the magnetic field of the electromagnetic radiation will have a significant effect are traced using Floquet theory. The analysis reveals that the threshold intensity for a significant response of the magnetic field of the radiation at the second harmonic of the incident radiation can be reduced to {10}12 {{W}}{{cm}}-2 for off resonant and even lower for resonant interaction. This phenomenon has already been observed indirectly in experiments [1, 2]. Induced magnetizing current due to the magnetic force is shown to originate from a modified dielectric response, which may be useful in future magneto-optic devices, solar energy harvesting, and studying the ultrafast dynamics in doped dielectrics.

  11. Relativistic particle acceleration by obliquely propagating electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Villalón, Elena; Burke, William J.

    1987-12-01

    The relativistic equations of motion are analyzed for charged particles in a magnetized plasma and externally imposed electromagnetic fields (ω, k), which have wave vectors k that are at arbitrary angles. The particle energy is obtained from a set of nonlinear differential equations, as a function of time, initial conditions, and cyclotron harmonic numbers. For a given cyclotron resonance, the energy oscillates in time within the limits of a potential well; stochastic acceleration occurs if the widths of different Hamiltonian potentials overlap. The net energy gain for a given harmonic increase with the angle of propagation, and decreases as the magnitude of the wave magnetic field increases. Potential applications of these results to the acceleration of ionsopheric electrons are presented.

  12. Electromagnetic field triggered drug and chemical delivery via liposomes

    DOEpatents

    Liburdy, R.P.

    1993-03-02

    The present invention relates to a system and to a method of delivering a drug to a preselected target body site of a patient, comprising the steps of encapsulating the chemical agent within liposomes, essentially temperature insensitive, i.e. not having a specific predetermined phase transition temperature within the specific temperature range of drug administration; administering the liposomes to the target body site; and subjecting the target body site to nonionizing electromagnetic fields in an area of the preselected target body in order to release the chemical agent from the liposomes at a temperature of between about +10 and 65 C. The invention further relates to the use of the liposomes to bind to the surface of or to enter target tissue or an organ in a living system, and, when subjected to a nonionizing field, to release a drug from the liposomes into the target site.

  13. Geometric entropy and edge modes of the electromagnetic field

    NASA Astrophysics Data System (ADS)

    Donnelly, William; Wall, Aron C.

    2016-11-01

    We calculate the vacuum entanglement entropy of Maxwell theory in a class of curved spacetimes by Kaluza-Klein reduction of the theory onto a two-dimensional base manifold. Using two-dimensional duality, we express the geometric entropy of the electromagnetic field as the entropy of a tower of scalar fields, constant electric and magnetic fluxes, and a contact term, whose leading-order divergence was discovered by Kabat. The complete contact term takes the form of one negative scalar degree of freedom confined to the entangling surface. We show that the geometric entropy agrees with a statistical definition of entanglement entropy that includes edge modes: classical solutions determined by their boundary values on the entangling surface. This resolves a long-standing puzzle about the statistical interpretation of the contact term in the entanglement entropy. We discuss the implications of this negative term for black hole thermodynamics and the renormalization of Newton's constant.

  14. Photon merging and splitting in electromagnetic field inhomogeneities

    NASA Astrophysics Data System (ADS)

    Gies, Holger; Karbstein, Felix; Seegert, Nico

    2016-04-01

    We investigate photon merging and splitting processes in inhomogeneous, slowly varying electromagnetic fields. Our study is based on the three-photon polarization tensor following from the Heisenberg-Euler effective action. We put special emphasis on deviations from the well-known constant field results, also revisiting the selection rules for these processes. In the context of high-intensity laser facilities, we analytically determine compact expressions for the number of merged/split photons as obtained in the focal spots of intense laser beams. For the parameter range of typical petawatt class laser systems as pump and probe, we provide estimates for the numbers of signal photons attainable in an actual experiment. The combination of frequency upshifting, polarization dependence and scattering off the inhomogeneities renders photon merging an ideal signature for the experimental exploration of nonlinear quantum vacuum properties.

  15. Twists and rotations of solar magnetic fields

    NASA Astrophysics Data System (ADS)

    Piddington, J. H.

    1981-04-01

    A detailed review is given of evidence for the emergence of solar magnetic fields as helically twisted flux ropes, made up of hundreds of thousands of individually twisted flux fibers and reaching concentrations greater than 4000 gauss. The initial pitch angle of the twists is estimated as less than 10 deg in the submerged flux ropes and 1 deg in the fibers, with large-factor increases during (and following) emergence. The upward transmission of magnetic stresses and motions from submerged flux rope sections are major factors in solar physics, with the helical twists accounting for the creation of sunspots and for their stability, fine structure, and mode of decay. They are basic features of solar atmospheric structures, from the largest flare events and prominences to arch filaments and the smallest network components.

  16. A. A. Ukhtomskii`s dominance principle of brain activity in the perception of electromagnetic fields

    SciTech Connect

    Kholodov, Yu.A.

    1994-07-01

    Preliminary instruction of the subject plays an important role in the perception of weak electromagnetic fields acting on the hand. Active attention to a potential effect amplifies a brain state that can be called caution dominance and arises spontaneously with a {open_quotes}placebo{close_quotes} or an electromagnetic field. The radar principle of brain operation is discussed among the physiological mechanisms through which electromagnetic fields act on an organism.

  17. A. A. Ukhtomskii's dominance principle of brain activity in the perception of electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Kholodov, Yu. A.

    1994-01-01

    Preliminary instruction of the subject plays an important role in the perception of weak electromagnetic fields acting on the hand. Active attention to a potential effect amplifies a brain state that can be called caution dominance and arises spontaneously with a “placebo” or an electromagnetic field. The radar principle of brain operation is discussed among the physiological mechanisms through which electromagnetic fields act on an organism.

  18. Assessment of the Genotoxic Effects of High Peak-Power Pulsed Electromagnetic Fields

    DTIC Science & Technology

    2003-06-01

    the Genotoxic Effects of High Peak-Power Pulsed Electromagnetic Fields 5c. PROGRAM ELEMENT NUMBER 5d. PROJECT NUMBER 5d. TASK NUMBER 6. AUTHOR(S) Dr... Genotoxic Effects of High Peak-Power Pulsed Electromagnetic Fields (EMFs) (From 1 June 2002 to 31 May 2003 for 12 months) Nikolai Konstantinovich Chemeris...International Science and Technology Center (ISTC), Moscow. 2 ISTC 2350 Assessment of the Genotoxic Effects of High Peak-Power Pulsed Electromagnetic Fields

  19. JET ROTATION DRIVEN BY MAGNETOHYDRODYNAMIC SHOCKS IN HELICAL MAGNETIC FIELDS

    SciTech Connect

    Fendt, Christian

    2011-08-10

    In this paper, we present a detailed numerical investigation of the hypothesis that a rotation of astrophysical jets can be caused by magnetohydrodynamic (MHD) shocks in a helical magnetic field. Shock compression of the helical magnetic field results in a toroidal Lorentz force component that will accelerate the jet material in the toroidal direction. This process transforms magnetic angular momentum (magnetic stress) carried along the jet into kinetic angular momentum (rotation). The mechanism proposed here only works in a helical magnetic field configuration. We demonstrate the feasibility of this mechanism by axisymmetric MHD simulations in 1.5 and 2.5 dimensions using the PLUTO code. In our setup, the jet is injected into the ambient gas with zero kinetic angular momentum (no rotation). We apply different dynamical parameters for jet propagation such as the jet internal Alfven Mach number and fast magnetosonic Mach number, the density contrast of the jet to the ambient medium, and the external sonic Mach number of the jet. The mechanism we suggest should work for a variety of jet applications, e.g., protostellar or extragalactic jets, and internal jet shocks (jet knots) or external shocks between the jet and the ambient gas (entrainment). For typical parameter values for protostellar jets, the numerically derived rotation feature looks consistent with the observations, i.e., rotational velocities of 0.1%-1% of the jet bulk velocity.

  20. Rotation in a reversed field pinch with active feedback stabilization of resistive wall modes

    NASA Astrophysics Data System (ADS)

    Cecconello, M.; Menmuir, S.; Brunsell, P. R.; Kuldkepp, M.

    2006-09-01

    Active feedback stabilization of multiple resistive wall modes (RWMs) has been successfully proven in the EXTRAP T2R reversed field pinch. One of the features of plasma discharges operated with active feedback stabilization, in addition to the prolongation of the plasma discharge, is the sustainment of the plasma rotation. Sustained rotation is observed both for the internally resonant tearing modes (TMs) and the intrinsic impurity oxygen ions. Good quantitative agreement between the toroidal rotation velocities of both is found: the toroidal rotation is characterized by an acceleration phase followed, after one wall time, by a deceleration phase that is slower than in standard discharges. The TMs and the impurity ions rotate in the same poloidal direction with also similar velocities. Poloidal and toroidal velocities have comparable amplitudes and a simple model of their radial profile reproduces the main features of the helical angular phase velocity. RWMs feedback does not qualitatively change the TMs behaviour and typical phenomena such as the dynamo and the 'slinky' are still observed. The improved sustainment of the plasma and TMs rotation occurs also when feedback only acts on internally non-resonant RWMs. This may be due to an indirect positive effect, through non-linear coupling between TMs and RWMs, of feedback on the TMs or to a reduced plasma-wall interaction affecting the plasma flow rotation. Electromagnetic torque calculations show that with active feedback stabilization the TMs amplitude remains well below the locking threshold condition for a thick shell. Finally, it is suggested that active feedback stabilization of RWMs and current profile control techniques can be employed simultaneously thus improving both the plasma duration and its confinement properties.

  1. Impact of the strong electromagnetic field on the QCD effective potential for homogeneous Abelian gluon field configurations

    SciTech Connect

    Galilo, Bogdan V.; Nedelko, Sergei N.

    2011-11-01

    The one-loop quark contribution to the QCD effective potential for the homogeneous Abelian gluon field in the presence of an external strong electromagnetic field is evaluated. The structure of extrema of the potential as a function of the angles between chromoelectric, chromomagnetic, and electromagnetic fields is analyzed. In this setup, the electromagnetic field is considered as an external one while the gluon field represents domain structured nonperturbative gluon configurations related to the QCD vacuum in the confinement phase. Two particularly interesting gluon configurations, (anti-)self-dual and crossed orthogonal chromomagnetic and chromoelectric fields, are discussed specifically. Within this simplified framework it is shown that the strong electromagnetic fields can play a catalyzing role for a deconfinement transition. At the qualitative level, the present consideration can be seen as a highly simplified study of an impact of the electromagnetic fields generated in relativistic heavy ion collisions on the strongly interacting hadronic matter.

  2. Probing intergalactic magnetic fields with simulations of electromagnetic cascades

    NASA Astrophysics Data System (ADS)

    Alves Batista, Rafael; Saveliev, Andrey; Sigl, Günter; Vachaspati, Tanmay

    2016-10-01

    We determine the effect of intergalactic magnetic fields on the distribution of high-energy gamma rays by performing three-dimensional Monte Carlo simulations of the development of gamma-ray-induced electromagnetic cascades in the magnetized intergalactic medium. We employ the so-called "Large Sphere Observer" method to efficiently simulate blazar gamma ray halos. We study magnetic fields with a Batchelor spectrum and with maximal left- and right-handed helicities. We also consider the case of sources whose jets are tilted with respect to the line of sight. We verify the formation of extended gamma ray halos around the source direction, and observe spiral-like patterns if the magnetic field is helical. We apply the Q -statistics to the simulated halos to extract their spiral nature and also propose an alternative method, the S -statistics. Both methods provide a quantitative way to infer the helicity of the intervening magnetic fields from the morphology of individual blazar halos for magnetic field strengths B ≳10-15 G and magnetic coherence lengths Lc≳100 Mpc . We show that the S -statistics has a better performance than the Q -statistics when assessing magnetic helicity from the simulated halos.

  3. Setting prudent public health policy for electromagnetic field exposures.

    PubMed

    Carpenter, David O; Sage, Cindy

    2008-01-01

    Electromagnetic fields (EMF) permeate our environment, coming both from such natural sources as the sun and from manmade sources like electricity, communication technologies and medical devices. Although life on earth would not be possible without sunlight, increasing evidence indicates that exposures to the magnetic fields associated with electricity and to communication frequencies associated with radio, television, WiFi technology, and mobile cellular phones pose significant hazards to human health. The evidence is strongest for leukemia from electricity-frequency fields and for brain tumors from communication-frequency fields, yet evidence is emerging for an association with other diseases as well, including neurodegenerative diseases. Some uncertainty remains as to the mechanism(s) responsible for these biological effects, and as to which components of the fields are of greatest importance. Nevertheless, regardless of whether the associations are causal, the strengths of the associations are sufficiently strong that in the opinion of the authors, taking action to reduce exposures is imperative, especially for the fetus and children. Inaction is not compatible with the Precautionary Principle, as enunciated by the Rio Declaration. Because of ubiquitous exposure, the rapidly expanding development of new EMF technologies and the long latency for the development of such serious diseases as brain cancers, the failure to take immediate action risks epidemics of potentially fatal diseases in the future.

  4. Electromagnetic Form Factors of Hadrons in Quantum Field Theories

    SciTech Connect

    Dominguez, C. A.

    2008-10-13

    In this talk, recent results are presented of calculations of electromagnetic form factors of hadrons in the framework of two quantum field theories (QFT), (a) Dual-Large N{sub c} QCD (Dual-QCD{sub {infinity}}) for the pion, proton, and {delta}(1236), and (b) the Kroll-Lee-Zumino (KLZ) fully renormalizable Abelian QFT for the pion form factor. Both theories provide a QFT platform to improve on naive (tree-level) Vector Meson Dominance (VMD). Dual-QCD{sub {infinity}} provides a tree-level improvement by incorporating an infinite number of zero-width resonances, which can be subsequently shifted from the real axis to account for the time-like behaviour of the form factors. The renormalizable KLZ model provides a QFT improvement of VMD in the framework of perturbation theory. Due to the relative mildness of the {rho}{pi}{pi} coupling, and the size of loop suppression factors, the perturbative expansion is well defined in spite of this being a strong coupling theory. Both approaches lead to considerable improvements of VMD predictions for electromagnetic form factors, in excellent agreement with data.

  5. Electromagnetic field strength levels surrounding electronic article surveillance (EAS) systems.

    PubMed

    Harris, C; Boivin, W; Boyd, S; Coletta, J; Kerr, L; Kempa, K; Aronow, S

    2000-01-01

    Electronic article surveillance (EAS) is used in many applications throughout the world to prevent theft. EAS systems produce electromagnetic (EM) energy around exits to create an EM interrogation zone through which protected items must pass before leaving the establishment. Specially designed EAS tags are attached to these items and must either be deactivated or removed prior to passing through the EAS EM interrogation zone to prevent the alarm from sounding. Recent reports in the scientific literature have noted the possibility that EM energy transmitted by EAS systems may interfere with the proper operation of sensitive electronic medical devices. The Food and Drug Administration has the regulatory responsibility to ensure the safety and effectiveness of medical devices. Because of the possibility of electromagnetic interference (EMI) between EAS systems and electronic medical devices, in situ measurements of the electric and magnetic fields were made around various types of EAS systems. Field strength levels were measured around four types of EAS systems: audio frequency magnetic, pulsed magnetic resonant, radio frequency, and microwave. Field strengths from these EAS systems varied with magnetic fields as high as 1073.6 Am(-1) (in close proximity to the audio frequency magnetic EAS system towers), and electric fields up to 23.8 Vm(-1) (in close proximity to the microwave EAS system towers). Medical devices are only required to withstand 3 Vm(-1) by the International Electrotechnical Commission's current medical device standards. The modulation scheme of the signal transmitted by some types of EAS systems (especially the pulsed magnetic resonant) has been shown to be more likely to cause EMI with electronic medical devices. This study complements other work in the field by attaching specific characteristics to EAS transmitted EM energy. The quantitative data could be used to relate medical device EMI with specific field strength levels and signal waveforms

  6. ON THE ROTATION OF THE MAGNETIC FIELD ACROSS THE HELIOPAUSE

    SciTech Connect

    Opher, M.; Drake, J. F.

    2013-12-01

    Based on the difference between the orientation of the interstellar and the solar magnetic fields, there was an expectation by the community that the magnetic field direction will rotate dramatically across the heliopause (HP). Recently, the Voyager team concluded that Voyager 1 (V1) crossed into interstellar space last year. The question is then why there was no significant rotation in the direction of the magnetic field across the HP. Here we present simulations that reveal that strong rotations in the direction of the magnetic field at the HP at the location of V1 (and Voyager 2) are not expected. The solar magnetic field strongly affects the drapping of the interstellar magnetic field (B {sub ISM}) around the HP. B {sub ISM} twists as it approaches the HP and acquires a strong T component (East-West). The strong increase in the T component occurs where the interstellar flow stagnates in front of the HP. At this same location the N component B{sub N} is significantly reduced. Above and below, the neighboring B {sub ISM} lines also twist into the T direction. This behavior occurs for a wide range of orientations of B {sub ISM}. The angle δ = asin (B{sub N} /B) is small (around 10°-20°), as seen in the observations. Only after some significant distance outside the HP is the direction of the interstellar field distinguishably different from that of the Parker spiral.

  7. Electron interaction with the spin angular momentum of the electromagnetic field

    NASA Astrophysics Data System (ADS)

    O’Connell, R. F.

    2017-02-01

    We give a simple derivation and expansion of a recently proposed new relativistic interaction between the electron and the spin angular momentum of the electromagnetic field in quantum electrodynamics (QED). Our derivation is based on the work of Møller, who pointed out that, in special relativity, a particle with spin must always have a finite extension. After generalizing Møller’s classical result to include both rotation and quantum effects, we show that it leads to a new contribution to the energy, which is the special relativistic interaction term. In addition, we show that all relativistic terms involving spin terms arising from the Dirac equation may be obtained by this method.

  8. PIC simulation of electrodeless plasma thruster with rotating electric field

    SciTech Connect

    Nomura, Ryosuke; Ohnishi, Naofumi; Nishida, Hiroyuki

    2012-11-27

    For longer lifetime of electric propulsion system, an electrodeless plasma thruster with rotating electric field have been proposed utilizing a helicon plasma source. The rotating electric field may produce so-called Lissajous acceleration of helicon plasma in the presence of diverging magnetic field through a complicated mechanism originating from many parameters. Two-dimensional simulations of the Lissajous acceleration were conducted by a code based on Particle-In-Cell (PIC) method and Monte Carlo Collision (MCC) method for understanding plasma motion in acceleration area and for finding the optimal condition. Obtained results show that azimuthal current depends on ratio of electron drift radius to plasma region length, AC frequency, and axial magnetic field. When ratio of cyclotron frequency to the AC frequency is higher than unity, reduction of the azimuthal current by collision effect is little or nothing.

  9. Electrodeless RF Plasma Propulsion by Rotating Magnetic Field Method

    NASA Astrophysics Data System (ADS)

    Furukawa, Takerku; Takizawa, Kohei; Kuwahara, Daisuke; Shinohara, Shunjiro

    2016-10-01

    Electric propulsion scheme is promising in the field of the space propulsion because of high fuel efficiency and long operating time. However, this time is limited due to the loss of electrodes contacting with plasmas directly. In order to solve this problem, we have proposed electrodeless acceleration schemes, e.g., a rotating magnetic field (RMF) scheme. In this RMF scheme, we use two pairs of 5 turns RMF coils with AC currents, which have a 90 deg. phase difference. The rotating magnetic field induces azimuthal current j by a nonlinear effect. Then, plasma is accelerated by the axial Lorentz force using the product of j and the radial component of external magnetic field. We have investigated the effect of the RMF current frequency f, and 24% increase of ion velocity in the case of f = 3 MHz. We will present the experimental results, using lower f and gas pressure, and also discuss the penetration of RMF into the plasma.

  10. Using strong electromagnetic fields to control x-ray processes.

    SciTech Connect

    Young, L.; Buth, C.; Dunford, R. W.; Ho, P.; Kanter, E. P.; Kraessig, B.; Peterson, E. R.; Rohringer, N.; Santra, R.; Southworth, S. H.

    2010-06-01

    Exploration of a new ultrafast-ultrasmall frontier in atomic and molecular physics has begun. Not only is is possible to control outer-shell electron dynamics with intense ultrafast optical lasers, but now control of inner-shell processes has become possible by combining intense infrared/optical lasers with tunable sources of X-ray radiation. This marriage of strong-field laser and X-ray physics has led to the discovery of methods to control reversibly resonant X-ray absorption in atoms and molecules on ultrafast timescales. Using a strong optical dressing field, resonant X-ray absorption in atoms can be markedly suppressed, yielding an example of electromagnetically induced transparency for x rays. Resonant X-ray absorption can also be controlled in molecules using strong non-resonant, polarized laser fields to align the framework of a molecule, and therefore its unoccupied molecular orbitals to which resonant absorption occurs. At higher laser intensities, ultrafast field ionization produces an irreversible change in X-ray absorption. Finally, the advent of X-ray free electron lasers enables first exploration of non-linear X-ray processes.

  11. [Effects of radiofrequency electromagnetic fields on mammalian spermatogenesis].

    PubMed

    Susa, Martina; Pavicić, Ivan

    2007-12-01

    This article reviews studies about the effects of radiofrequency electromagnetic (RF EM) fields on male reproductive system and reproductive health in mammals. According to current data, there are almost 4 million active mobile phone lines in Croatia while this number has risen to 2 billion in the world. Increased use of mobile technology raises scientific and public concern about possible hazardous effects of RF fields on human health. The effects of radiofrequencies on reproductive health and consequences for the offspring are still mainly unknown. A number of in vivo and in vitro studies indicated that RF fields could interact with charged intracellular macromolecular structures. Results of several laboratory studies on animal models showed how the RF fields could affect the mammalian reproductive system and sperm cells. Inasmuch as, in normal physiological conditions spermatogenesis is a balanced process of division, maturation and storage of cells, it is particularly vulnerable to the chemical and physical environmental stimuli. Especially sensitive could be the cytoskeleton, composed of charged proteins; actin, intermedial filaments and microtubules. Cytoskeleton is a functional and structural part of the cell that has important role in the sperm motility, and is actively involved in the morphologic changes that occur during mammalian spermiogenesis.

  12. Equations of a moving mirror and the electromagnetic field

    NASA Astrophysics Data System (ADS)

    Octavio Castaños, Luis; Weder, Ricardo

    2015-06-01

    We consider a system composed of a mobile slab and the electromagnetic field. We assume that the slab is made of a material that has the following properties when it is at rest: it is linear, isotropic, non-magnetizable, and ohmic with zero free charge density. Using instantaneous Lorentz transformations, we deduce the set of self-consistent equations governing the dynamics of the system and we obtain approximate equations to first order in the velocity and the acceleration of the slab. As a consequence of the motion of the slab, the field must satisfy a wave equation with damping and slowly varying coefficients plus terms that are small when the time-scale of the evolution of the mirror is much larger than that of the field. Also, the motion of the slab and its interaction with the field introduce two effects in the slab’s equation of motion. The first one is a position- and time-dependent mass related to the effective mass taken in phenomenological treatments of this type of systems. The second one is a velocity-dependent force that can give rise to friction and that is related to the much sought cooling of mechanical objects.

  13. Electromagnetic field-induced stimulation of Bruton's tyrosine kinase.

    PubMed

    Kristupaitis, D; Dibirdik, I; Vassilev, A; Mahajan, S; Kurosaki, T; Chu, A; Tuel-Ahlgren, L; Tuong, D; Pond, D; Luben, R; Uckun, F M

    1998-05-15

    Here we present evidence that exposure of DT40 lymphoma B-cells to low energy electromagnetic fields (EMF) results in activation of phospholipase C-gamma 2 (PLC-gamma2), leading to increased inositol phospholipid turnover. PLC-gamma2 activation in EMF-stimulated cells is mediated by stimulation of the Bruton's tyrosine kinase (BTK), a member of the Src-related TEC family of protein tyrosine kinases, which acts downstream of LYN kinase and upstream of PLC-gamma2. B-cells rendered BTK-deficient by targeted disruption of the btk gene did not show enhanced PLC-gamma2 activation in response to EMF exposure. Introduction of the wild-type (but not a kinase domain mutant) human btk gene into BTK-deficient B-cells restored their EMF responsiveness. Thus, BTK exerts a pivotal and mandatory function in initiation of EMF-induced signaling cascades in B-cells.

  14. Finite element modeling of electromagnetic fields and waves using NASTRAN

    NASA Technical Reports Server (NTRS)

    Moyer, E. Thomas, Jr.; Schroeder, Erwin

    1989-01-01

    The various formulations of Maxwell's equations are reviewed with emphasis on those formulations which most readily form analogies with Navier's equations. Analogies involving scalar and vector potentials and electric and magnetic field components are presented. Formulations allowing for media with dielectric and conducting properties are emphasized. It is demonstrated that many problems in electromagnetism can be solved using the NASTRAN finite element code. Several fundamental problems involving time harmonic solutions of Maxwell's equations with known analytic solutions are solved using NASTRAN to demonstrate convergence and mesh requirements. Mesh requirements are studied as a function of frequency, conductivity, and dielectric properties. Applications in both low frequency and high frequency are highlighted. The low frequency problems demonstrate the ability to solve problems involving media inhomogeneity and unbounded domains. The high frequency applications demonstrate the ability to handle problems with large boundary to wavelength ratios.

  15. Could Radiotherapy Effectiveness Be Enhanced by Electromagnetic Field Treatment?

    PubMed Central

    Francisco, Artacho-Cordón; del Mar, Salinas-Asensio María; Irene, Calvente; Sandra, Ríos-Arrabal; Josefa, León; Elisa, Román-Marinetto; Nicolás, Olea; Isabel, Núñez María

    2013-01-01

    One of the main goals in radiobiology research is to enhance radiotherapy effectiveness without provoking any increase in toxicity. In this context, it has been proposed that electromagnetic fields (EMFs), known to be modulators of proliferation rate, enhancers of apoptosis and inductors of genotoxicity, might control tumor recruitment and, thus, provide therapeutic benefits. Scientific evidence shows that the effects of ionizing radiation on cellular compartments and functions are strengthened by EMF. Although little is known about the potential role of EMFs in radiotherapy (RT), the radiosensitizing effect of EMFs described in the literature could support their use to improve radiation effectiveness. Thus, we hypothesized that EMF exposure might enhance the ionizing radiation effect on tumor cells, improving the effects of RT. The aim of this paper is to review reports of the effects of EMFs in biological systems and their potential therapeutic benefits in radiotherapy. PMID:23867611

  16. Annals of conflicting results: looking back on electromagnetic field research.

    PubMed

    Schoen, D

    1996-11-15

    Few environmental health issues are as contentious as the question of whether exposure to electromagnetic fields (EMFs) from power lines increases cancer risk. Among the many actors in this controversy, epidemiologists have played the leading role in raising the question and motivating research. Epidemiologic studies of the effects of exposure to power-line EMFs include the investigation by Dr. Gilles Thériault and colleagues into incidence rates of cancer among electric-utility workers in Quebec, Ontario and France. With the development of personal dosimeters to measure exposure to electric, magnetic and pulsed EMFs, occupational studies in the 1990s have made an important methodologic advance. But, as Thériault explains, improvements in assessing exposure have not yet translated into clear and consistent findings.

  17. Electromagnetic field energy density in homogeneous negative index materials.

    PubMed

    Shivanand; Webb, Kevin J

    2012-05-07

    An exact separation of both electric and magnetic energies into stored and lost energies is shown to be possible in the special case when the wave impedance is independent of frequency. A general expression for the electromagnetic energy density in such a dispersive medium having a negative refractive index is shown to be accurate in comparison with numerical results. Using an example metamaterial response that provides a negative refractive index, it is shown that negative time-averaged stored energy can occur. The physical meaning of this negative energy is explained as the energy temporarily borrowed by the field from the material. This observation for negative index materials is of interest when approaching properties for a perfect lens. In the broader context, the observation of negative stored energy is of consequence in the study of dispersive materials.

  18. Paternal occupational exposure to electromagnetic fields and neuroblastoma in offspring

    SciTech Connect

    Wilkins, J.R. 3d.; Hundley, V.D. )

    1990-06-01

    Investigators in Texas have reported an association between paternal employment in jobs linked with exposure to electromagnetic fields and risk of neuroblastoma in offspring. In an attempt to replicate this finding, the authors conducted a case-control study in Ohio. A total of 101 incident cases of neuroblastoma were identified through the Columbus (Ohio) Children's Hospital Tumor Registry. All cases were born sometime during the period 1942-1967. From a statewide roster of birth certificates, four controls were selected for each case, with individual matching on the case's year of birth, race, and sex, and the mother's county of residence at the time of the (index) child's birth. Multiple definitions were employed to infer the potential for paternal occupational exposure to electromagnetic fields from the industry/occupation statements on the birth certificates. Case-control comparisons revealed adjusted odds ratios ranging in magnitude from 0.5 to 1.9. For two of the exposure definitions employed--both of which are similar to one used by the Texas investigators--the corresponding odds ratios were modestly elevated (odds ratios = 1.6 and 1.9). Notably, the magnitude of these odds ratios is not inconsistent with the Texas findings, where the exposure definition referred to yielded an odds ratio of 2.1. Because the point estimates in this study are imprecise, and because the biologic plausibility of the association is uncertain, the results reported here must be interpreted cautiously. However, the apparent consistency between two independent studies suggests that future evaluation of the association is warranted.

  19. Nonlinear Compton scattering in a strong rotating electric field

    NASA Astrophysics Data System (ADS)

    Raicher, Erez; Eliezer, Shalom; Zigler, Arie

    2016-12-01

    The nonlinear Compton scattering rate in a rotating electric field is explicitly calculated. For this purpose, an approximate solution to the Klein-Gordon equation in the presence of a rotating electric field is applied. An analytical expression for the emission rate is obtained, as well as a simplified approximation adequate for implementation in kinetic codes. The spectrum is numerically calculated for present-day optical and x-ray laser parameters. The results are compared to the standard Volkov-Ritus rate for a particle in a plane wave, which is commonly assumed to be valid for a rotating electric field under certain conditions. Substantial deviations between the two models, in both the radiated power and the spectral shape, are demonstrated. First, the typical number of photons participating in the scattering process is much smaller compared to the Volkov-Ritus rate, resulting in up to an order of magnitude lower emitted power. Furthermore, our model predicts a discrete harmonic spectrum for electrons with low asymptotic momentum compared to the field amplitude. This discrete structure is a clear imprint of the electric field frequency, as opposed to the Volkov-Ritus rate, which reduces to the constant crossed field rate for the physical conditions under consideration. Our model predictions can be tested with present-day laser facilities.

  20. Rotating field collector subsystem phase 1 study and evaluation

    NASA Astrophysics Data System (ADS)

    Jones, D.; Eibling, J. A.

    1982-10-01

    The rotating field collector system is an alternative concept in which all heliostats are mounted on a single large platform which rotates around a tower to track the azumuthal angle of the Sun. Each heliostat is mounted to the platform with appropriate pivots, linkage, and controls to provide the additional positioning required to properly direct the solar radiation onto the receiver. The results are presented of the first phase of a study to investigate the technical and economic merits of a particular type of rotating field collector subsystem. The large pie-shaped platform would revolve over an array of support pedestals by means of a roller at the top of each pedestal. Several heliostats were built to demonstrate their construction features, and the operation of both flat and amphitheater rotating fields was studied. Work included an analysis of the concepts, development of modifications and additions to make the system comply with design criteria, and cost estimates to be used for comparison with other heliostat subsystems. Because of considerably high cost estimates, the focus of a large part of the study was directed toward developing lower cost designs of major components.

  1. NMR system and method having a permanent magnet providing a rotating magnetic field

    DOEpatents

    Schlueter, Ross D [Berkeley, CA; Budinger, Thomas F [Berkeley, CA

    2009-05-19

    Disclosed herein are systems and methods for generating a rotating magnetic field. The rotating magnetic field can be used to obtain rotating-field NMR spectra, such as magic angle spinning spectra, without having to physically rotate the sample. This result allows magic angle spinning NMR to be conducted on biological samples such as live animals, including humans.

  2. Do the standard expressions for the electromagnetic field momentum need any modifications?

    NASA Astrophysics Data System (ADS)

    Singal, Ashok K.

    2016-10-01

    We investigate here the question raised in the literature about the correct expression for the electromagnetic field momentum, especially when static or stationary fields are involved. For this, we examine a couple of simple but intriguing cases. First, we consider a system configuration in which electromagnetic field momentum is present even though the system is stationary. We trace the electromagnetic momentum to be present in the form of a continuous transport of electromagnetic energy from one part of the system to another, without causing any net change in the energy of the system. In a second case, we show that the electromagnetic momentum is zero irrespective of whether the charged system is static or in motion, even though the electromagnetic energy is present throughout. We demonstrate that the conventional formulation of electromagnetic field momentum describes the systems consistently without any real contradictions. Here, we also make exposition of a curiosity where electromagnetic energy decreases when the charged system gains velocity. Then we discuss the more general question that has been raised: Are the conventional formulas for energy-momentum of electromagnetic fields valid for all cases? Specifically, in the case of so-called "bound fields," do we need to change to some modified definitions? We show that in all cases it is only the conventional formulas that lead to results consistent with the rest of physics, including the special theory of relativity, and that any proposed modifications are thus superfluous.

  3. Electromagnetic field and cylindrical compact objects in modified gravity

    NASA Astrophysics Data System (ADS)

    Yousaf, Z.; Bhatti, M. Zaeem ul Haq

    2016-05-01

    In this paper, we have investigated the role of different fluid parameters particularly electromagnetic field and f(R) corrections on the evolution of cylindrical compact object. We have explored the modified field equations, kinematical quantities and dynamical equations. An expression for the mass function has been found in comparison with the Misner-Sharp formalism in modified gravity, after which different mass-radius diagrams are drawn. The coupled dynamical transport equation have been formulated to discuss the role of thermoinertial effects on the inertial mass density of the cylindrical relativistic interior. Finally, we have presented a framework, according to which all possible solutions of the metric f(R)-Maxwell field equations coupled with static fluid can be written through set of scalar functions. It is found that modified gravity induced by Lagrangians f(R) = αR2, f(R) = αR2 - βR and f(R)=α R^2-β R/1+γ R are likely to host more massive cylindrical compact objects with smaller radii as compared to general relativity.

  4. Analyzing Exposures to Electromagnetic Fields in an Intensive Care Unit

    PubMed Central

    Gökmen, Necati; Erdem, Sabri; Toker, Kadir Atilla; Öçmen, Elvan; Gökmen, Başak Ilgım; Özkurt, Ahmet

    2016-01-01

    Objective In this study, we conducted a numerical analysis of exposure to electromagnetic fields (EMFs) in a hospital’s intensive care unit that is one of the most crucial one in terms of hazardous areas among all service units. This is a new study for measuring exposure to EMFs in an intensive care unit as well as other healthcare services in Turkey. Methods We measured the EMFs in the intensive care unit with a SRM-3006 (selective radiation metre), which was used for measurement of the absolute and the limit values of high frequency EMFs. The measurement points were chosen to represent the highest levels of exposure to which a person might be subjected. We obtained a dataset that included 5929 observations, with 96 extreme values, through measuring the magnetic field in terms of V/m. Results The measurements show the frequency varies from 47 MHz to 2.5 GHz as 17 frequency ranges at the measurement point as well. According to these findings, the referenced maximum safety limit was not exceeded. However, it was also found that mobile telecommunication was the most critical cause of magnetic fields. Conclusion Further studies need to be performed with different frequency antennas to assess the EMFs in intensive care units. PMID:27909603

  5. Neutrino Astrophysics in Slowly Rotating Spacetimes Permeated by Nonlinear Electrodynamics Fields

    NASA Astrophysics Data System (ADS)

    Mosquera Cuesta, Herman J.

    2017-02-01

    Many theoretical and astrophysical arguments involve consideration of the effects of super strong electromagnetic fields and the rotation during the late stages of core-collapse supernovae. In what follows, we solve Einstein field equations that are minimally coupled to an arbitrary (current-free) Born–Infeld nonlinear Lagrangian L(F,G) of electrodynamics (NLED) in the slow rotation regime a ≪ r+ (outer horizon size), up to first order in a/r. We cross-check the physical properties of such NLED spacetime w.r.t. against the Maxwell one. A study case on both neutrino flavor ({ν }e\\to {ν }μ ,{ν }τ ) oscillations and flavor+helicity (spin) flip ({ν }e\\to {\\overline{ν }}μ ,τ ) gyroscopic precession proves that in the spacetime of a slowly rotating nonlinear charged black hole (RNCBH), the neutrino dynamics translates into a positive enhancement of the r-process (reduction of the electron fraction Ye < 0.5). Consequently, it guarantees successful hyperluminous core-collapse supernova explosions due to the enlargement of the number and amount of decaying nuclide species. This posits that, as far as the whole luminosity is concerned, hypernovae will be a proof of the formation of astrophysical RNCBH.

  6. Singularities in the Transverse Fields of Electromagnetic Waves. II. Observations on the Electric Field

    NASA Astrophysics Data System (ADS)

    Hajnal, J. V.

    1987-12-01

    Electromagnetic waves propagating in free space contain three kinds of singularities called C lines, S surfaces and disclinations. The paper describes observations of these singularities in two different monochromatic microwave fields. The observations confirm all the theoretically predicted properties of the singularities that could be tested. As expected, the singularities were found to be prominent structural features of the fields and in consequence to provide an economical means of characterizing their structure. A notable result is the observation of both right-hand and left-hand C lines in a field that is nominally uniformly left-hand circularly polarized. This is in agreement with the previous assertion that, in general, electromagnetic wavefields contain both right-hand and left-hand polarized regions.

  7. [Medical and biologic research of electromagnetic fields in radiofrequencies range. Results and prospects].

    PubMed

    Kaliada, T V; Vishnevskiĭ, A M; Gorodetskiĭ, B N; Plekhanov, V P; Kuznetsov, A V

    2014-01-01

    The authors present research findings on the problem of technology-related electromagnetic fields as an occupational risk factor of workers health disturbances, and on the issue of prevention measures development against this adverse physical factor effects. Prospects for further research development in the field of electromagnetic safety are discussed.

  8. Spontaneous topological transitions of electromagnetic fields in spatially inhomogeneous C P -odd domains

    NASA Astrophysics Data System (ADS)

    Tuchin, Kirill

    2016-12-01

    Metastable C P -odd domains of the hot QCD matter are coupled to QED via the chiral anomaly. The topology of electromagnetic field in these domains is characterized by magnetic helicity. It is argued, using the Maxwell-Chern-Simons model, that spatial inhomogeneity of the domains induces spontaneous transitions of electromagnetic field between the opposite magnetic helicity states.

  9. Bacterial growth rates are influenced by cellular characteristics of individual species when immersed in electromagnetic fields.

    PubMed

    Tessaro, Lucas W E; Murugan, Nirosha J; Persinger, Michael A

    2015-03-01

    Previous studies have shown that exposure to extremely low-frequency electromagnetic fields (ELF-EMFs) have negative effects on the rate of growth of bacteria. In the present study, two Gram-positive and two Gram-negative species were exposed to six magnetic field conditions in broth cultures. Three variations of the 'Thomas' pulsed frequency-modulated pattern; a strong-static "puck" magnet upwards of 5000G in intensity; a pair of these magnets rotating opposite one another at ∼30rpm; and finally a strong dynamic magnetic field generator termed the 'Resonator' with an average intensity of 250μT were used. Growth rate was discerned by optical density (OD) measurements every hour at 600nm. ELF-EMF conditions significantly affected the rates of growth of the bacterial cultures, while the two static magnetic field conditions were not statistically significant. Most interestingly, the 'Resonator' dynamic magnetic field increased the rates of growth of three species (Staphylococcus epidermidis, Staphylococcus aureus, and Escherichia coli), while slowing the growth of one (Serratia marcescens). We suggest that these effects are due to individual biophysical characteristics of the bacterial species.

  10. Modeling of interactions of electromagnetic fields with human bodies

    NASA Astrophysics Data System (ADS)

    Caputa, Krzysztof

    Interactions of electromagnetic fields with the human body have been a subject of scientific interest and public concern. In recent years, issues in power line field effects and those of wireless telephones have been in the forefront of research. Engineering research compliments biological investigations by quantifying the induced fields in biological bodies due to exposure to external fields. The research presented in this thesis aims at providing reliable tools, and addressing some of the unresolved issues related to interactions with the human body of power line fields and fields produced by handheld wireless telephones. The research comprises two areas, namely development of versatile models of the human body and their visualisation, and verification and application of numerical codes to solve selected problems of interest. The models of the human body, which are based on the magnetic resonance scans of the body, are unique and differ considerably from other models currently available. With the aid of computer software developed, the models can be arranged to different postures, and medical devices can be accurately placed inside them. A previously developed code for modeling interactions of power line fields with biological bodies has been verified by rigorous, quantitative inter-laboratory comparison for two human body models. This code has been employed to model electromagnetic interference (EMI) of the magnetic field with implanted cardiac pacemakers. In this case, the correct placement and representation of the pacemaker leads are critical, as simplified computations have been shown to result in significant errors. In modeling interactions of wireless communication devices, the finite difference time domain technique (FDTD) has become a de facto standard. The previously developed code has been verified by comparison with the analytical solution for a conductive sphere. While previously researchers limited their verifications to principal axes of the sphere

  11. Idiopathic environmental intolerance attributed to electromagnetic fields (formerly 'electromagnetic hypersensitivity'): An updated systematic review of provocation studies.

    PubMed

    Rubin, G James; Nieto-Hernandez, Rosa; Wessely, Simon

    2010-01-01

    Idiopathic Environmental Intolerance attributed to electromagnetic fields (IEI-EMF; formerly 'electromagetic hypersensitivity') is a medically unexplained illness in which subjective symptoms are reported following exposure to electrical devices. In an earlier systematic review, we reported data from 31 blind provocation studies which had exposed IEI-EMF volunteers to active or sham electromagnetic fields and assessed whether volunteers could detect these fields or whether they reported worse symptoms when exposed to them. In this article, we report an update to that review. An extensive literature search identified 15 new experiments. Including studies reported in our earlier review, 46 blind or double-blind provocation studies in all, involving 1175 IEI-EMF volunteers, have tested whether exposure to electromagnetic fields is responsible for triggering symptoms in IEI-EMF. No robust evidence could be found to support this theory. However, the studies included in the review did support the role of the nocebo effect in triggering acute symptoms in IEI-EMF sufferers. Despite the conviction of IEI-EMF sufferers that their symptoms are triggered by exposure to electromagnetic fields, repeated experiments have been unable to replicate this phenomenon under controlled conditions. A narrow focus by clinicians or policy makers on bioelectromagnetic mechanisms is therefore, unlikely to help IEI-EMF patients in the long-term.

  12. Exposure to electromagnetic fields aboard high-speed electric multiple unit trains.

    PubMed

    Niu, D; Zhu, F; Qiu, R; Niu, Q

    2016-01-01

    High-speed electric multiple unit (EMU) trains generate high-frequency electric fields, low-frequency magnetic fields, and high-frequency wideband electromagnetic emissions when running. Potential human health concerns arise because the electromagnetic disturbances are transmitted mainly into the car body from windows, and from there to passengers and train staff. The transmission amount and amplitude distribution characteristics that dominate electromagnetic field emission need to be studied, and the exposure level of electromagnetic field emission to humans should be measured. We conducted a series of tests of the on board electromagnetic field distribution on several high-speed railway lines. While results showed that exposure was within permitted levels, the possibility of long-term health effects should be investigated.

  13. Three-dimensional electromagnetic breathers in carbon nanotubes with the field inhomogeneity along their axes

    NASA Astrophysics Data System (ADS)

    Zhukov, Alexander V.; Bouffanais, Roland; Fedorov, Eduard G.; Belonenko, Mikhail B.

    2013-10-01

    We study the propagation of extremely short electromagnetic three-dimensional bipolar pulses in an array of semiconductor carbon nanotubes. The heterogeneity of the pulse field along the axis of the nanotubes is accounted for the first time. The evolution of the electromagnetic field and the charge density of the sample are described by Maxwell's equations supplemented by the continuity equation. Our analysis reveals for the first time the possibility of propagation of three-dimensional electromagnetic breathers in CNTs arrays. Specifically, we found that the propagation of short electromagnetic pulse induces a redistribution of the electron density in the sample.

  14. Electromagnetic cascades and the depletion of intense fields

    NASA Astrophysics Data System (ADS)

    Bulanov, Stepan; Seipt, Daniel; Heinzl, Thomas; Marklund, Mattias; Ji, Qing; Steinke, Sven; Schroeder, Carl; Esarey, Eric; Leemans, Wim P.

    2016-10-01

    The interaction of electrons, positrons, and photons with intense electromagnetic fields gives rise to multi-photon Compton and Breit-Wheeler processes. It is shown that electrons and/or positrons undergo a cascade-type process involving multiple emissions of photons. These photons can consequently convert into electron-positron pairs. As a result charged particles quickly lose their energy developing an exponentially decaying energy distribution. Moreover the multi-photon nature of Compton and Breit-Wheeler processes implies the absorption of a significant number of photons. As a result, the interaction of a highly charged electron bunch with an intense laser pulse can lead to a significant depletion of the laser pulse energy, thus rendering the external field approximation invalid. The relevance of these results to the proposed BELLA-i beamline at BELLA center at LBNL is discussed. We acknowledge support from the Office of Science of the US DOE under Contract No. DE-AC02-05CH11231.

  15. Electromagnetic fluid drift turbulence in static ergodic magnetic fields

    NASA Astrophysics Data System (ADS)

    Reiser, D.; Scott, B.

    2005-12-01

    Numerical simulations of three-dimensional nonlinear electromagnetic fluid drift turbulence in a tokamak plasma with externally applied stochastic magnetic-field perturbations are presented. The contributions to the radial particle transport due to nonlinearities arising from E ×B advection and magnetic flutter are investigated for perturbation fields of varying strengths in the cases of low and high collisionalities. The perturbation strength is varied to study the physics for Chirikov parameters above 1. In all the cases considered a significant increase of E ×B transport is found. A static contribution in the density and velocity perturbations contributes significantly to the total radial E ×B transport. For low collisionality, the external perturbation leads to enhanced density and velocity fluctuations over a broad range in the toroidal wave-number spectrum, resulting in an enhanced turbulent flux. For high collisionality, the density fluctuations stay roughly the same and the velocity fluctuations are increased in an intermediate range of the toroidal wave number spectrum, separated from the maximum of the density fluctuations, thus leaving the turbulent flux almost unchanged.

  16. Electromagnetically induced transparency resonances inverted in magnetic field

    SciTech Connect

    Sargsyan, A.; Sarkisyan, D. E-mail: david@ipr.sci.am; Pashayan-Leroy, Y.; Leroy, C.; Cartaleva, S.; Wilson-Gordon, A. D.; Auzinsh, M.

    2015-12-15

    The phenomenon of electromagnetically induced transparency (EIT) is investigated in a Λ-system of the {sup 87}Rb D{sub 1} line in an external transverse magnetic field. Two spectroscopic cells having strongly different values of the relaxation rates γ{sub rel} are used: an Rb cell with antirelaxation coating (L ∼ 1 cm) and an Rb nanometric- thin cell (nanocell) with a thickness of the atomic vapor column L = 795 nm. For the EIT in the nanocell, we have the usual EIT resonances characterized by a reduction in the absorption (dark resonance (DR)), whereas for the EIT in the Rb cell with an antirelaxation coating, the resonances demonstrate an increase in the absorption (bright resonances (BR)). We suppose that such an unusual behavior of the EIT resonances (i.e., the reversal of the sign from DR to BR) is caused by the influence of an alignment process. The influence of alignment strongly depends on the configuration of the coupling and probe frequencies as well as on the configuration of the magnetic field.

  17. Extremely low frequency electromagnetic fields and cancer: the epidemiologic evidence.

    PubMed Central

    Bates, M N

    1991-01-01

    This paper reviews the epidemiologic evidence that low frequency electromagnetic fields generated by alternating current may be a cause of cancer. Studies examining residential exposures of children and adults and studies of electrical and electronics workers are reviewed. Using conventional epidemiologic criteria for inferring causal associations, including strength and consistency of the relationship, biological plausibility, and the possibility of bias as an explanation, it is concluded that the evidence is strongly suggestive that such radiation is carcinogenic. The evidence is strongest for brain and central nervous system cancers in electrical workers and children. Weaker evidence supports an association with leukemia in electrical workers. Some evidence also exists for an association with melanoma in electrical workers. Failure to find consistent evidence of a link between residential exposures and adult cancers may be attributable to exposure misclassification. Studies so far have used imperfect surrogates for any true biologically effective magnetic field exposure. The resulting exposure misclassification has produced relative risk estimates that understate any true risk. PMID:1821368

  18. Scalar, electromagnetic, and gravitational perturbations of Kerr-Newman black holes in the slow-rotation limit

    NASA Astrophysics Data System (ADS)

    Pani, Paolo; Berti, Emanuele; Gualtieri, Leonardo

    2013-09-01

    In Einstein-Maxwell theory, according to classic uniqueness theorems, the most general stationary black-hole solution is the axisymmetric Kerr-Newman metric, which is defined by three parameters: mass, spin and electric charge. The radial and angular dependence of gravitational and electromagnetic perturbations in the Kerr-Newman geometry do not seem to be separable. In this paper we circumvent this problem by studying scalar, electromagnetic and gravitational perturbations of Kerr-Newman black holes in the slow-rotation limit. We extend (and provide details of) the analysis presented in a recent Letter [P. Pani, E. Berti, and L. Gualtieri, Phys. Rev. Lett. 110, 241103 (2013)]. Working at linear order in the spin, we present the first detailed derivation of the axial and polar perturbation equations in the gravito-electromagnetic case, and we compute the corresponding quasinormal modes for any value of the electric charge. Our study is the first self-consistent stability analysis of the Kerr-Newman metric, and in principle it can be extended to any order in the small rotation parameter. We find numerical evidence that the axial and polar sectors are isospectral at first order in the spin and speculate on the possible implications of this result.

  19. Growth inhibition of Staphylococcus aureus induced by low-frequency electric and electromagnetic fields.

    PubMed

    Obermeier, Andreas; Matl, Florian Dominik; Friess, Wolfgang; Stemberger, Axel

    2009-05-01

    Magnetic field therapy is an established technique in the treatment of pseudarthrosis. In cases of osteomylitis, palliation is also observed. This study focuses on the impact of different electric and electromagnetic fields on the growth of Staphylococcus aureus by in vitro technologies. Cultures of Staphylococcus aureus in fluid and gel-like medium were exposed to a low-frequency electromagnetic field, an electromagnetic field combined with an additional electric field, a sinusoidal electric field and a static electric field. In gel-like medium no significant difference between colony-forming units of exposed samples and non-exposed references was detected. In contrast, Staphylococcus aureus concentrations in fluid medium could clearly be reduced under the influence of the four different applied fields within 24 h of experiment. The strongest effects were observed for the direct current electric field which could decrease CFU/ml of 37%, and the low-frequency electromagnetic field with additional induced electric alternating field with a decrease of Staphylococci concentration by 36%. The effects of the electromagnetic treatment on Staphylococci within fluid medium are significantly higher than in gel-like medium. The application of low-frequency electromagnetic fields corroborates clinical situations of bone infections during magnetic field therapy.

  20. Influence of strong field vacuum polarization on gravitational-electromagnetic wave interaction

    SciTech Connect

    Forsberg, M.; Brodin, G.; Papadopoulos, D.

    2010-07-15

    The interaction between gravitational and electromagnetic waves in the presence of a static magnetic field is studied. The field strength of the static field is allowed to surpass the Schwinger critical field, such that the QED effects of vacuum polarization and magnetization are significant. Equations governing the interaction are derived and analyzed. It turns out that the energy conversion from gravitational to electromagnetic waves can be significantly altered due to the QED effects. The consequences of our results are discussed.

  1. The Rotation of the Solar Photospheric Magnetic Field

    NASA Astrophysics Data System (ADS)

    Xu, J. C.; Gao, P. X.

    2016-12-01

    The rotational characteristics of the solar photospheric magnetic field at four flux ranges are investigated together with the total flux of active regions (MFar) and quiet regions (MFqr). The first four ranges (MF1-4) are (1.5-2.9) × 1018, (2.9-32.0) × 1018, (3.20-4.27) × 1019, and (4.27-38.01) × 1019, respectively (the unit is Mx per element). Daily values of the flux data are extracted from magnetograms of the Michelson Doppler Imager on board the Solar and Heliospheric Observatory. Lomb-Scargle periodograms show that only MF2, MF4, MFqr, and MFar exhibit rotational periods. The periods of the first three types of flux are very similar, i.e., 26.20, 26.23, and 26.24 days, respectively, while that of MFar is longer, 26.66 days. This indicates that active regions rotate more slowly than quiet regions on average, and strong magnetic fields tend to repress the surface rotation. Sinusoidal function fittings and cross-correlation analyses reveal that MFar leads MF2 and MF4 by 5 and 1 days, respectively. This is speculated to be related with the decaying of active regions. MF2 and MFar are negatively correlated, while both MF4 and MFqr are positively correlated with MFar. At the timescale of the solar activity cycle, MFar leads (negatively) MF2 by around one year (350 days), and leads MF4 by about 3 rotation periods (82 days). The relation between MF2 and MFar may be explained by the possibility that the former mainly comes from a higher latitude, or emerges from the subsurface shear layer. We conjecture that MF4 may partly come from the magnetic flux of active regions; this verifies previous results that were obtained with indirect solar magnetic indices.

  2. Rotational Velocities of Field Blue Horizontal Branch Stars

    NASA Astrophysics Data System (ADS)

    Weafer, V. K.; Fulbright, J. P.

    2001-12-01

    This study is motivated by interest in the much-debated ``second-parameter" problem. Deep mixing, driven by angular momentum, has been proposed as a second parameter controlling horizontal-branch colour morphology (Sweigart & Mengel 1979). Observations of low-metallicity field giant stars show little evidence of deep mixing (Kraft 1994, Wallerstein et al. 1997, Gratton et al. 2000). We therefore expect that field horizontal branch stars may show little evidence of rotation. We have used high-resolution spectra from Keck and Lick observatories to find the projected rotational velocity (v sin i) of 44 blue (-0.04 <= B-V <= 0.20) horizontal branch stars in the halo field. Selected Fe and Ti absorption lines were co-added in velocity space to create an average line profile for each star. To find v sin i, the average profile was compared to similarly-averaged synthesised lines. We have compared the v sin i values of the sample to those of the blue horizontal branch stars in the second-parameter globular-cluster pair, M3 and M13 (Peterson et al. 1995). Although further work is needed to completely establish the velocity distribution of the sample, we have found that the sample has rotational velocities more similar to M13 than to M3, with at least 5 stars showing v sin i > = 25 km/s.

  3. OBLIQUELY ROTATING PULSARS: SCREENING OF THE INDUCTIVE ELECTRIC FIELD

    SciTech Connect

    Melrose, D. B.; Yuen Rai

    2012-02-01

    Pulsar electrodynamics has been built up by taking ingredients from two models, the vacuum-dipole model, which ignores the magnetosphere but includes the inductive electric field due to the obliquely rotating magnetic dipole, and the corotating-magnetosphere model, which neglects the vacuum inductive electric field and assumes a corotating magnetosphere. We argue that the inductive field can be neglected only if it is screened by a current, J{sub sc}, which we calculate for a rigidly rotating magnetosphere. Screening of the parallel component of the inductive field can be effective, but the perpendicular component cannot be screened in a pulsar magnetosphere. The incompletely screened inductive electric field has not been included in any model for a pulsar magnetosphere, and taking it into account has important implications. One effect is that it implies that the magnetosphere cannot be corotating, and we suggest that drift relative to corotation offers a natural explanation for the drifting of subpulses. A second effect is that this screening of the parallel inductive electric field must break down in the outer magnetosphere, and this offers a natural explanation for the acceleration of the electrons that produce pulsed gamma-ray emission.

  4. Effects of pulsed electromagnetic field frequencies on the osteogenic differentiation of human mesenchymal stem cells.

    PubMed

    Luo, Fei; Hou, Tianyong; Zhang, Zehua; Xie, Zhao; Wu, Xuehui; Xu, Jianzhong

    2012-04-01

    The purpose of this study was to evaluate the effect of different frequencies of pulsed electromagnetic fields on the osteogenic differentiation of human mesenchymal stem cells. Third-generation human mesenchymal stem cells were irradiated with different frequencies of pulsed electromagnetic fields, including 5, 25, 50, 75, 100, and 150 Hz, with a field intensity of 1.1 mT, for 30 minutes per day for 21 days. Changes in human mesenchymal stem cell morphology were observed using phase contrast microscopy. Alkaline phosphatase activity and osteocalcin expression were also determined to evaluate human mesenchymal stem cell osteogenic differentiation.Different effects were observed on human mesenchymal stem cell osteoblast induction following exposure to different pulsed electromagnetic field frequencies. Levels of human mesenchymal stem cell differentiation increased when the pulsed electromagnetic field frequency was increased from 5 hz to 50 hz, but the effect was weaker when the pulsed electromagnetic field frequency was increased from 50 Hz to 150 hz. The most significant effect on human mesenchymal stem cell differentiation was observed at of 50 hz.The results of the current study show that pulsed electromagnetic field frequency is an important factor with regard to the induction of human mesenchymal stem cell differentiation. Furthermore, a pulsed electromagnetic field frequency of 50 Hz was the most effective at inducing human mesenchymal stem cell osteoblast differentiation in vitro.

  5. Electromagnetic Radiation System (EMRS) for Susceptibility Testing.

    DTIC Science & Technology

    ELECTROMAGNETIC COMPATIBILITY, *ELECTROMAGNETIC SUSCEPTIBILITY, COMMUNICATION EQUIPMENT, ELECTRONIC EQUIPMENT, ELECTROMAGNETIC RADIATION , ANTENNAS, ELECTROMAGNETIC INTERFERENCE, RADAR SIGNALS, RADIO SIGNALS, FIELD INTENSITY.

  6. Stellar Rotation in the Orion Nebula Cluster Flanking Fields

    NASA Astrophysics Data System (ADS)

    Rebull, L.

    1999-12-01

    We present an optical study of four 45' x 45' fields centered 35' north, south, east, and west of the Orion Nebula Cluster center. We have measured V and I C photometry for 5000 stars in three of these fields, and U photometry for 1600 of those. We have obtained spectral classifications for 300 of the stars with UVI C photometry plus an additional 200 stars located outside the area of our photometric survey. Based on these data, we find 230 active accretion disk candidates. We have also obtained time-series data for stars in each of these four fields, and 300 periods derived from these data will be presented and discussed. In recent months, several investigators have presented rotation rates for stars in the Trapezium and its immediate environs. The paradigm (e.g. Choi and Herbst 1996) until now has been that the slow rotators are still (magnetically) locked to their disks, and that the fast rotators have dissipated their disks sufficiently as to allow spinup. Herbst et al. (2000) claim they see a bimodal distribution of rotators in Orion; Stassun et al. (1999) claim not to see such a distribution in a very similar region, and in fact cast doubt on the bimodality of the original distribution. Different selection effects (as well as different numbers of stars) are likely to be affecting these conclusions; the addition of data presented here will clarify the issues. This research has made use of data taken at McDonald Observatory (by R. Makidon and M. Adams), data taken at the KPNO 0.9m (with B. Patten and C. Pavlovsky), data taken through the WIYN-Queue program, software written by B. Patten, and partial funding via NASA Origins Grants (L. Hillenbrand and S. Strom).

  7. Effect of electromagnetic field exposure on the reproductive system

    PubMed Central

    Park, Chan Jin

    2012-01-01

    The safety of human exposure to an ever-increasing number and diversity of electromagnetic field (EMF) sources both at work and at home has become a public health issue. To date, many in vivo and in vitro studies have revealed that EMF exposure can alter cellular homeostasis, endocrine function, reproductive function, and fetal development in animal systems. Reproductive parameters reported to be altered by EMF exposure include male germ cell death, the estrous cycle, reproductive endocrine hormones, reproductive organ weights, sperm motility, early embryonic development, and pregnancy success. At the cellular level, an increase in free radicals and [Ca2+]i may mediate the effect of EMFs and lead to cell growth inhibition, protein misfolding, and DNA breaks. The effect of EMF exposure on reproductive function differs according to frequency and wave, strength (energy), and duration of exposure. In the present review, the effects of EMFs on reproductive function are summarized according to the types of EMF, wave type, strength, and duration of exposure at cellular and organism levels. PMID:22563544

  8. Effect of cyclophosphamide and electromagnetic fields on mouse bone marrow

    SciTech Connect

    Cadossi, R.; Zucchini, P.; Emilia, G.; Torelli, G. )

    1990-02-26

    The authors have previously shown that the exposure to low frequency pulsing electromagnetic fields (PEMF) of mice X-ray irradiated resulted in an increased damage to the bone marrow. The series of experiments here reported were designed to investigate the effect of PEMF exposure after intraperitoneum injection of 200mg/kg of cyclophosphamide (CY). Control mice were CY injected only; experimental mice were CY injected and then exposed to PEMF. Exposure to PEMF (24 hours/day) increased the rate of decline of white blood cells in peripheral blood. Spleen weight was statistically higher among control mice than among mice exposed to PEMF at day 6, 8 and 10 after CY injection. Spleen autoradiography proved to be higher among PEMF exposed mice than among controls at day 8 and 9 after CY injection. The grafting efficiency of the bone marrow obtained from control mice was higher than the grafting efficiency of the bone marrow recovered from mice exposed to PEMF. All these data indicate that the exposure to PEMF increases the cytotoxic effect of CY.

  9. Effects of Electromagnetic Fields on Automated Blood Cell Measurements.

    PubMed

    Vagdatli, Eleni; Konstandinidou, Vasiliki; Adrianakis, Nikolaos; Tsikopoulos, Ioannis; Tsikopoulos, Alexios; Mitsopoulou, Kyriaki

    2014-08-01

    The aim of this study is to investigate whether the electromagnetic fields associated with mobile phones and/or laptops interfere with blood cell counts of hematology analyzers. Random blood samples were analyzed on an Aperture Impedance hematology analyzer. The analysis was performed in four ways: (A) without the presence of any mobile phone or portable computer in use, (B) with mobile phones in use (B1: one mobile, B4: four mobiles), (C) with portable computers (laptops) in use (C1: one laptop, C3: three laptops), and (D) with four mobile phones and three laptops in use simultaneously. The results obtained demonstrated a statistically significant decrease in neutrophil, erythrocyte, and platelet count and an increase in lymphocyte count, mean corpuscular volume, and red blood cell distribution width, notably in the B4 group. Despite this statistical significance, in clinical practice, only the red blood cell reduction could be taken into account, as the mean difference between the A and B4 group was 60,000 cells/µL. In group D, the analyzer gave odd results after 11 measurements and finally stopped working. The combined and multiple use of mobile phones and computers affects the function of hematology analyzers, leading to false results. Consequently, the use of such electronic devices must be avoided.

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

    PubMed Central

    Vegh, Viktor; Reutens, David C.

    2016-01-01

    Object 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. Materials and Methods 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. Results 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. Conclusions 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. PMID:27271886

  11. The Dosimetric Impact of Prostate Rotations During Electromagnetically Guided External-Beam Radiation Therapy

    SciTech Connect

    Amro, Hanan; Hamstra, Daniel A.; Mcshan, Daniel L.; Sandler, Howard; Vineberg, Karen; Hadley, Scott; Litzenberg, Dale

    2013-01-01

    Purpose: To study the impact of daily rotations and translations of the prostate on dosimetric coverage during radiation therapy (RT). Methods and Materials: Real-time tracking data for 26 patients were obtained during RT. Intensity modulated radiation therapy plans meeting RTOG 0126 dosimetric criteria were created with 0-, 2-, 3-, and 5-mm planning target volume (PTV) margins. Daily translations and rotations were used to reconstruct prostate delivered dose from the planned dose. D{sub 95} and V{sub 79} were computed from the delivered dose to evaluate target coverage and the adequacy of PTV margins. Prostate equivalent rotation is a new metric introduced in this study to quantify prostate rotations by accounting for prostate shape and length of rotational lever arm. Results: Large variations in prostate delivered dose were seen among patients. Adequate target coverage was met in 39%, 65%, and 84% of the patients for plans with 2-, 3-, and 5-mm PTV margins, respectively. Although no correlations between prostate delivered dose and daily rotations were seen, the data showed a clear correlation with prostate equivalent rotation. Conclusions: Prostate rotations during RT could cause significant underdosing even if daily translations were managed. These rotations should be managed with rotational tolerances based on prostate equivalent rotations.

  12. Occupational exposure to electromagnetic fields and acute leukaemia: analysis of a case-control study

    PubMed Central

    Willett, E; McKinney, P; Fear, N; Cartwright, R; Roman, E

    2003-01-01

    Aims: To investigate whether the risk of acute leukaemia among adults is associated with occupational exposure to electromagnetic fields. Methods: Probable occupational exposure to electromagnetic fields at higher than typical residential levels was investigated among 764 patients diagnosed with acute leukaemia during 1991–96 and 1510 sex and age matched controls. A job exposure matrix was applied to the self reported employment histories to determine whether or not a subject was exposed to electromagnetic fields. Risks were assessed using conditional logistic regression for a matched analysis. Results: Study subjects considered probably ever exposed to electromagnetic fields at work were not at increased risk of acute leukaemia compared to those considered never exposed. Generally, no associations were observed on stratification by sex, leukaemia subtype, number of years since exposure stopped, or occupation; there was no evidence of a dose-response effect using increasing number of years exposed. However, relative to women considered never exposed, a significant excess of acute lymphoblastic leukaemia was observed among women probably exposed to electromagnetic fields at work that remained increased irrespective of time prior to diagnosis or job ever held. Conclusion: This large population based case-control study found little evidence to support an association between occupational exposure to electromagnetic fields and acute leukaemia. While an excess of acute lymphoblastic leukaemia among women was observed, it is unlikely that occupational exposure to electromagnetic fields was responsible, given that increased risks remained during periods when exposure above background levels was improbable. PMID:12883018

  13. Rotating sample magnetometer for cryogenic temperatures and high magnetic fields.

    PubMed

    Eisterer, M; Hengstberger, F; Voutsinas, C S; Hörhager, N; Sorta, S; Hecher, J; Weber, H W

    2011-06-01

    We report on the design and implementation of a rotating sample magnetometer (RSM) operating in the variable temperature insert (VTI) of a cryostat equipped with a high-field magnet. The limited space and the cryogenic temperatures impose the most critical design parameters: the small bore size of the magnet requires a very compact pick-up coil system and the low temperatures demand a very careful design of the bearings. Despite these difficulties the RSM achieves excellent resolution at high magnetic field sweep rates, exceeding that of a typical vibrating sample magnetometer by about a factor of ten. In addition the gas-flow cryostat and the high-field superconducting magnet provide a temperature and magnetic field range unprecedented for this type of magnetometer.

  14. Exposure to electromagnetic fields from laptop use of "laptop" computers.

    PubMed

    Bellieni, C V; Pinto, I; Bogi, A; Zoppetti, N; Andreuccetti, D; Buonocore, G

    2012-01-01

    Portable computers are often used at tight contact with the body and therefore are called "laptop." The authors measured electromagnetic fields (EMFs) laptop computers produce and estimated the induced currents in the body, to assess the safety of laptop computers. The authors evaluated 5 commonly used laptop of different brands. They measured EMF exposure produced and, using validated computerized models, the authors exploited the data of one of the laptop computers (LTCs) to estimate the magnetic flux exposure of the user and of the fetus in the womb, when the laptop is used at close contact with the woman's womb. In the LTCs analyzed, EMF values (range 1.8-6 μT) are within International Commission on Non-Ionizing Radiation (NIR) Protection (ICNIRP) guidelines, but are considerably higher than the values recommended by 2 recent guidelines for computer monitors magnetic field emissions, MPR II (Swedish Board for Technical Accreditation) and TCO (Swedish Confederation of Professional Employees), and those considered risky for tumor development. When close to the body, the laptop induces currents that are within 34.2% to 49.8% ICNIRP recommendations, but not negligible, to the adult's body and to the fetus (in pregnant women). On the contrary, the power supply induces strong intracorporal electric current densities in the fetus and in the adult subject, which are respectively 182-263% and 71-483% higher than ICNIRP 98 basic restriction recommended to prevent adverse health effects. Laptop is paradoxically an improper site for the use of a LTC, which consequently should be renamed to not induce customers towards an improper use.

  15. The regenerative effects of electromagnetic field on spinal cord injury.

    PubMed

    Ross, Christina L; Syed, Ishaq; Smith, Thomas L; Harrison, Benjamin S

    2017-01-01

    Traumatic spinal cord injury (SCI) is typically the result of direct mechanical impact to the spine, leading to fracture and/or dislocation of the vertebrae along with damage to the surrounding soft tissues. Injury to the spinal cord results in disruption of axonal transmission of signals. This primary trauma causes secondary injuries that produce immunological responses such as neuroinflammation, which perpetuates neurodegeneration and cytotoxicity within the injured spinal cord. To date there is no FDA-approved pharmacological agent to prevent the development of secondary SCI and induce regenerative processes aimed at healing the spinal cord and restoring neurological function. An alternative method to electrically activate spinal circuits is the application of a noninvasive electromagnetic field (EMF) over intact vertebrae. The EMF method of modulating molecular signaling of inflammatory cells emitted in the extra-low frequency range of <100 Hz, and field strengths of <5 mT, has been reported to decrease inflammatory markers in macrophages, and increase endogenous mesenchymal stem cell (MSC) proliferation and differentiation rates. EMF has been reported to promote osteogenesis by improving the effects of osteogenic media, and increasing the proliferation of osteoblasts, while inhibiting osteoclast formation and increasing bone matrix in vitro. EMF has also been shown to increase chondrogenic markers and collagen and induce neural differentiation, while increasing cell viability by over 50%. As advances are made in stem cell technologies, stabilizing the cell line after differentiation is crucial to SCI repair. Once cell-seeded scaffolds are implanted, EMF may be applied outside the wound for potential continued adjunct treatment during recovery.

  16. Dynamic magnetic fields remote-control apoptosis via nanoparticle rotation.

    PubMed

    Zhang, Enming; Kircher, Moritz F; Koch, Martin; Eliasson, Lena; Goldberg, S Nahum; Renström, Erik

    2014-04-22

    The ability to control the movement of nanoparticles remotely and with high precision would have far-reaching implications in many areas of nanotechnology. We have designed a unique dynamic magnetic field (DMF) generator that can induce rotational movements of superparamagnetic iron oxide nanoparticles (SPIONs). We examined whether the rotational nanoparticle movement could be used for remote induction of cell death by injuring lysosomal membrane structures. We further hypothesized that the shear forces created by the generation of oscillatory torques (incomplete rotation) of SPIONs bound to lysosomal membranes would cause membrane permeabilization, lead to extravasation of lysosomal contents into the cytoplasm, and induce apoptosis. To this end, we covalently conjugated SPIONs with antibodies targeting the lysosomal protein marker LAMP1 (LAMP1-SPION). Remote activation of slow rotation of LAMP1-SPIONs significantly improved the efficacy of cellular internalization of the nanoparticles. LAMP1-SPIONs then preferentially accumulated along the membrane in lysosomes in both rat insulinoma tumor cells and human pancreatic beta cells due to binding of LAMP1-SPIONs to endogenous LAMP1. Further activation of torques by the LAMP1-SPIONs bound to lysosomes resulted in rapid decrease in size and number of lysosomes, attributable to tearing of the lysosomal membrane by the shear force of the rotationally activated LAMP1-SPIONs. This remote activation resulted in an increased expression of early and late apoptotic markers and impaired cell growth. Our findings suggest that DMF treatment of lysosome-targeted nanoparticles offers a noninvasive tool to induce apoptosis remotely and could serve as an important platform technology for a wide range of biomedical applications.

  17. Acute neuroprotective effects of extremely low-frequency electromagnetic fields after traumatic brain injury in rats.

    PubMed

    Yang, Yang; Li, Ling; Wang, Yan-Gang; Fei, Zhou; Zhong, Jun; Wei, Li-Zhou; Long, Qian-Fa; Liu, Wei-Ping

    2012-05-10

    Traumatic brain injury commonly has a result of a short window of opportunity between the period of initial brain injury and secondary brain injury, which provides protective strategies and can reduce damages of brain due to secondary brain injury. Previous studies have reported neuroprotective effects of extremely low-frequency electromagnetic fields. However, the effects of extremely low-frequency electromagnetic fields on neural damage after traumatic brain injury have not been reported yet. The present study aims to investigate effects of extremely low-frequency electromagnetic fields on neuroprotection after traumatic brain injury. Male Sprague-Dawley rats were used for the model of lateral fluid percussion injury, which were placed in non-electromagnetic fields and 15 Hz (Hertz) electromagnetic fields with intensities of 1 G (Gauss), 3 G and 5 G. At various time points (ranging from 0.5 to 30 h) after lateral fluid percussion injury, rats were treated with kainic acid (administered by intraperitoneal injection) to induce apoptosis in hippocampal cells. The results were as follows: (1) the expression of hypoxia-inducible factor-1α was dramatically decreased during the neuroprotective time window. (2) The kainic acid-induced apoptosis in the hippocampus was significantly decreased in rats exposed to electromagnetic fields. (3) Electromagnetic fields exposure shortened the escape time in water maze test. (4) Electromagnetic fields exposure accelerated the recovery of the blood-brain barrier after brain injury. These findings revealed that extremely low-frequency electromagnetic fields significantly prolong the window of opportunity for brain protection and enhance the intensity of neuroprotection after traumatic brain injury.

  18. Voyager measurement of the rotation period of Saturn's magnetic field

    NASA Technical Reports Server (NTRS)

    Desch, M. D.; Kaiser, M. L.

    1981-01-01

    Saturn's radio rotation period was determined using measurements made by the planetary radio astronomy experiment onboard the Voyager spacecraft. The sidereal period deduced, 10 hr 39 min 24 sec ? 7 sec, is within the 10 hr to 11 hr range of optical periods derived from a century of atmospheric spot and Doppler spectroscopy observations. The radio rotation period is presumably that of the planet's magnetic field. A provisional Saturn longitude convention is proposed and equations are provided to compute a longitude ephemeris and to transform between the proposed system and the (10 hr 14 min) system used for the Pioneer 11/Saturn encounter. The degree of longitude smearing which could result over the long term from the merging of data sets organized in this system is evaluated. No evidence of control of the radio emission by any of Saturn's satellites was found.

  19. Idiopathic environmental intolerance attributed to electromagnetic fields: a content analysis of British newspaper reports.

    PubMed

    Eldridge-Thomas, Buffy; Rubin, G James

    2013-01-01

    Idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF) is a controversial condition in which people describe symptoms following exposure to electromagnetic fields from everyday electrical devices. However, double-blind experiments have found no convincing evidence that electromagnetic fields cause these symptoms. In this study, we assessed whether recent newspaper reporting in the UK reflected this scientific evidence. We searched a database of newspaper articles to identify all those that contained IEI-EMF related keywords and selected a random sample of 60 for content analysis. For our primary outcomes, we assessed how many articles mainly or wholly presented an electromagnetic cause for IEI-EMF and how many discussed unproven treatments for the condition such as strategies intended to reduce exposure to electromagnetic fields or the use of complementary and alternative therapies. We also assessed whether the type of information source used by a newspaper article (e.g. scientist, person with IEI-EMF, politician) or the type of newspaper (broadsheet, tabloid, local or regional) was associated with either outcome. Of the 60 articles, 43 (71.7%) presented a mainly electromagnetic cause, compared to 13 (21.7%) which presented mainly non-electromagnetic causes and 4 (6.7%) which did not discuss a cause. 29 (48.3%) did not mention any potential treatment, while 24 (40.0%) mentioned eletromagnetic field related strategies and 12 (20.0%) mentioned complementary or alternative therapies. Articles which quoted someone with IEI-EMF were significantly more likely to report an electromagnetic cause and to present unproven treatments. Those which used a scientist as a source were more likely to present a non-electromagnetic cause for the condition. The widespread poor reporting we identified is disappointing and has the potential for to encourage more people to misattribute their symptoms to electromagnetic fields. Scientists should remain engaged

  20. Impact of Low Frequency Electromagnetic Field Exposure on the Candida Albicans

    NASA Astrophysics Data System (ADS)

    Malíková, Ivona; Janoušek, Ladislav; Fantova, Vladyslava; Jíra, Jaroslav; Kříha, Vítĕzslav

    2015-03-01

    Effect of low frequency electromagnetic field on growth of selected microorganism is studied in the article. The diploid fungus that grows both as yeast and filamentous cell was chosen for this research. The theory of ion parametric resonance was taken as the base for studying the influence of electromagnetic field on biological structures. We tested the hypothesis, whether it is possible to observe the change in growth properties of Candida albicans with an AC electromagnetic field tuned to resonance with calcium ions cyclotron frequency.

  1. More on the covariant retarded Green's function for the electromagnetic field in de Sitter spacetime

    SciTech Connect

    Higuchi, Atsushi; Lee, Yen Cheong; Nicholas, Jack R.

    2009-11-15

    In a recent paper 2 it was shown in examples that the covariant retarded Green's functions in certain gauges for electromagnetism and linearized gravity can be used to reproduce field configurations correctly in spite of the spacelike nature of past infinity in de Sitter spacetime. In this paper we extend the work of Ref. 2 concerning the electromagnetic field and show that the covariant retarded Green's function with an arbitrary value of the gauge parameter reproduces the electromagnetic field from two opposite charges at antipodal points of de Sitter spacetime.

  2. Ultrastructural Study on Ultra-Low Frequency Electromagnetic Fields and Transfer Factor Effects on Skin Ulcers

    NASA Astrophysics Data System (ADS)

    Cadena, M. S. Reyes; Chapul, L. Sánchez; Pérez, Javiér; García, M. N. Jiménez; López, M. A. Jiménez; Espíndola, M. E. Sánchez; Perez, R. Paniagua; Hernández, N. A.; Paniagua, G.; Uribe, F.; Nava, J. J. Godina; Segura, M. A. Rodríguez

    2008-08-01

    We determined the effect of 120Hz ultra low frequency electromagnetic field (ELF) on the healing process of skin in 20 Wistar rats distributed in four groups in which chronic dermal ulcers had been produced. The first two groups received a dose of the transfer factor and interferon-beta (IFN-β) every 24 h during 12 days. The third group (positive control) received only electromagnetic field (ELF) sessions, and in the fourth group (negative control), no treatment was applied. The electromagnetic field was applied through a Helmholtz coils; 30 Gauss of intensity. Results shown histological changes that improve the healing process in animals subjected to ELF together with the transfer factor.

  3. Investigation of brain potentials in sleeping humans exposed to the electromagnetic field of mobile phones.

    PubMed

    Lebedeva, N N; Sulimov, A V; Sulimova, O P; Korotkovskaya, T I; Gailus, T

    2001-01-01

    An investigation was made of 8-hour EEG tracings of sleeping humans exposed to the electromagnetic field of a GSM-standard mobile phone. To analyze the EEG-patterns, manual scoring, nonlinear dynamics, and spectral analysis were employed. It was found that, when human beings were exposed to the electromagnetic field of a cellular phone, their cerebral cortex biopotentials revealed an increase in the alpha-range power density as compared to the placebo experiment. It was also found that the dimension of EEG correlation dynamics and the relation of sleep stages changed under the influence of the electromagnetic field of a mobile phone.

  4. Ultrastructural Study on Ultra-Low Frequency Electromagnetic Fields and Transfer Factor Effects on Skin Ulcers

    SciTech Connect

    Cadena, M. S. Reyes; Chapul, L. Sanchez; Perez, Javier; Garcia, M. N. Jimenez; Lopez, M. A. Jimenez; Espindola, M. E. Sanchez; Perez, R. Paniagua; Hernandez, N. A.; Paniagua, G.; Uribe, F.; Nava, J. J. Godina; Segura, M. A. Rodriguez

    2008-08-11

    We determined the effect of 120Hz ultra low frequency electromagnetic field (ELF) on the healing process of skin in 20 Wistar rats distributed in four groups in which chronic dermal ulcers had been produced. The first two groups received a dose of the transfer factor and interferon-beta (IFN-{beta}) every 24 h during 12 days. The third group (positive control) received only electromagnetic field (ELF) sessions, and in the fourth group (negative control), no treatment was applied. The electromagnetic field was applied through a Helmholtz coils; 30 Gauss of intensity. Results shown histological changes that improve the healing process in animals subjected to ELF together with the transfer factor.

  5. Entanglement control in a superconducting qubit system by an electromagnetic field

    NASA Astrophysics Data System (ADS)

    Zhang, Y. Q.; Xu, J. B.

    2011-08-01

    By making use of the dynamical algebraic method we investigate a quantum system consisting of superconducting qubits interacting with data buses, where the qubits are driven by time-dependent electromagnetic field and obtain an explicit expression of time evolution operator. Furthermore, we explore the entanglement dynamics and the influence of the time-dependent electromagnetic field and the initial state on the entanglement sudden death and birth for the system. It is shown that the entanglement between the qubit and bus as well as the entanglement sudden death and birth can be controlled by the time-dependent electromagnetic field.

  6. Dynamic model for electromagnetic field and heating patterns in loaded cylindrical cavities

    SciTech Connect

    Tian, Y.L.; Black, W.M.; Sa`adaldin, H.S.; Ahmad, I.; Silberglitt, R.

    1995-07-01

    An analytical solution for the electromagnetic fields in a cylindrical cavity, partially filled with a cylindrical dielectric has been recently reported. A program based on this solution has been developed and combined with the authors` previous program for heat transfer analysis. The new software has been used to simulate the dynamic temperature profiles of microwave heating and to investigate the role of electromagnetic field in heating uniformity and stability. The effects of cavity mode, cavity dimension, the dielectric properties of loads on electromagnetic field and heating patterns can be predicted using this software.

  7. Interaction of a two-level atom with single-mode optical field beyond the rotating wave approximation.

    PubMed

    Liu, Ju; Li, Zhi-Yuan

    2014-11-17

    One of the simplest models involving the atom-field interaction is the coupling of a single two-level atom with single-mode optical field. Under the rotating wave approximation, this problem is reduced to a form that can be solved exactly. But the approximation is only valid when the two levels are resonant or nearly resonant with the applied electromagnetic radiation. Here we present an analytical solution without the rotating wave approximation and applicable to general atom-field interaction far away from the resonance. We find that there exists remarkable influence of the initial phase of optical field on the Rabi oscillations and Rabi splitting, and this issue cannot be explored in the context of the rotating wave approximation. Due to the retention of the counter-rotating terms, higher-order harmonic appears during the Rabi splitting. The analytical solution suggests a way to regulate and control the quantum dynamics of a two-level atom and allows for exploring more essential features of the atom-field interaction.

  8. Induction of tamoxifen resistance in breast cancer cells by ELF electromagnetic fields

    SciTech Connect

    Girgert, Rainer . E-mail: rainer.girgert@med.uni-goettingen.de; Schimming, Hartmut; Koerner, Wolfgang; Gruendker, Carsten; Hanf, Volker

    2005-11-04

    The incidence of breast cancer in western societies has been rising ever since the Second World War. Besides the exposure to a multitude of new chemical compounds, electromagnetic field exposure has been linked to breast cancer through a radiation-mediated anti-melatonin pathway. We investigated, whether low-frequency electromagnetic field exposure interferes with the anti-estrogenic activity of tamoxifen. Two different clones of the breast cancer cell line MCF-7 were exposed to highly homogeneous 50 Hz electromagnetic fields and IC{sub 50} values were calculated from dose-response curves of tamoxifen at various field intensities. An intensity-dependent shift of tamoxifen dose-response curves to higher concentrations with a maximal response at 1.2 {mu}T was observed. Hypothetically, electromagnetic field exposure could contribute to tamoxifen resistance observed in breast cancer after long-term treatment.

  9. Induction of tamoxifen resistance in breast cancer cells by ELF electromagnetic fields.

    PubMed

    Girgert, Rainer; Schimming, Hartmut; Körner, Wolfgang; Gründker, Carsten; Hanf, Volker

    2005-11-04

    The incidence of breast cancer in western societies has been rising ever since the Second World War. Besides the exposure to a multitude of new chemical compounds, electromagnetic field exposure has been linked to breast cancer through a radiation-mediated anti-melatonin pathway. We investigated, whether low-frequency electromagnetic field exposure interferes with the anti-estrogenic activity of tamoxifen. Two different clones of the breast cancer cell line MCF-7 were exposed to highly homogeneous 50Hz electromagnetic fields and IC(50) values were calculated from dose-response curves of tamoxifen at various field intensities. An intensity-dependent shift of tamoxifen dose-response curves to higher concentrations with a maximal response at 1.2muT was observed. Hypothetically, electromagnetic field exposure could contribute to tamoxifen resistance observed in breast cancer after long-term treatment.

  10. Semiconductor Crystal Growth in Static and Rotating Magnetic fields

    NASA Technical Reports Server (NTRS)

    Volz, Martin

    2004-01-01

    Magnetic fields have been applied during the growth of bulk semiconductor crystals to control the convective flow behavior of the melt. A static magnetic field established Lorentz forces which tend to reduce the convective intensity in the melt. At sufficiently high magnetic field strengths, a boundary layer is established ahead of the solid-liquid interface where mass transport is dominated by diffusion. This can have a significant effect on segregation behavior and can eliminate striations in grown crystals resulting from convective instabilities. Experiments on dilute (Ge:Ga) and solid solution (Ge-Si) semiconductor systems show a transition from a completely mixed convective state to a diffusion-controlled state between 0 and 5 Tesla. In HgCdTe, radial segregation approached the diffusion limited regime and the curvature of the solid-liquid interface was reduced by a factor of 3 during growth in magnetic fields in excess of 0.5 Tesla. Convection can also be controlled during growth at reduced gravitational levels. However, the direction of the residual steady-state acceleration vector can compromise this effect if it cannot be controlled. A magnetic field in reduced gravity can suppress disturbances caused by residual transverse accelerations and by random non-steady accelerations. Indeed, a joint program between NASA and the NHMFL resulted in the construction of a prototype spaceflight magnet for crystal growth applications. An alternative to the suppression of convection by static magnetic fields and reduced gravity is the imposition of controlled steady flow generated by rotating magnetic fields (RMF)'s. The potential benefits of an RMF include homogenization of the melt temperature and concentration distribution, and control of the solid-liquid interface shape. Adjusting the strength and frequency of the applied magnetic field allows tailoring of the resultant flow field. A limitation of RMF's is that they introduce deleterious instabilities above a

  11. How good a clock is rotation? The stellar rotation-mass-age relationship for old field stars

    SciTech Connect

    Epstein, Courtney R.; Pinsonneault, Marc H. E-mail: pinsono@astronomy.ohio-state.edu

    2014-01-10

    The rotation-mass-age relationship offers a promising avenue for measuring the ages of field stars, assuming the attendant uncertainties to this technique can be well characterized. We model stellar angular momentum evolution starting with a rotation distribution from open cluster M37. Our predicted rotation-mass-age relationship shows significant zero-point offsets compared to an alternative angular momentum loss law and published gyrochronology relations. Systematic errors at the 30% level are permitted by current data, highlighting the need for empirical guidance. We identify two fundamental sources of uncertainty that limit the precision of rotation-based ages and quantify their impact. Stars are born with a range of rotation rates, which leads to an age range at fixed rotation period. We find that the inherent ambiguity from the initial conditions is important for all young stars, and remains large for old stars below 0.6 M {sub ☉}. Latitudinal surface differential rotation also introduces a minimum uncertainty into rotation period measurements and, by extension, rotation-based ages. Both models and the data from binary star systems 61 Cyg and α Cen demonstrate that latitudinal differential rotation is the limiting factor for rotation-based age precision among old field stars, inducing uncertainties at the ∼2 Gyr level. We also examine the relationship between variability amplitude, rotation period, and age. Existing ground-based surveys can detect field populations with ages as old as 1-2 Gyr, while space missions can detect stars as old as the Galactic disk. In comparison with other techniques for measuring the ages of lower main sequence stars, including geometric parallax and asteroseismology, rotation-based ages have the potential to be the most precise chronometer for 0.6-1.0 M {sub ☉} stars.

  12. How Good a Clock is Rotation? The Stellar Rotation-Mass-Age Relationship for Old Field Stars

    NASA Astrophysics Data System (ADS)

    Epstein, Courtney R.; Pinsonneault, Marc H.

    2014-01-01

    The rotation-mass-age relationship offers a promising avenue for measuring the ages of field stars, assuming the attendant uncertainties to this technique can be well characterized. We model stellar angular momentum evolution starting with a rotation distribution from open cluster M37. Our predicted rotation-mass-age relationship shows significant zero-point offsets compared to an alternative angular momentum loss law and published gyrochronology relations. Systematic errors at the 30% level are permitted by current data, highlighting the need for empirical guidance. We identify two fundamental sources of uncertainty that limit the precision of rotation-based ages and quantify their impact. Stars are born with a range of rotation rates, which leads to an age range at fixed rotation period. We find that the inherent ambiguity from the initial conditions is important for all young stars, and remains large for old stars below 0.6 M ⊙. Latitudinal surface differential rotation also introduces a minimum uncertainty into rotation period measurements and, by extension, rotation-based ages. Both models and the data from binary star systems 61 Cyg and α Cen demonstrate that latitudinal differential rotation is the limiting factor for rotation-based age precision among old field stars, inducing uncertainties at the ~2 Gyr level. We also examine the relationship between variability amplitude, rotation period, and age. Existing ground-based surveys can detect field populations with ages as old as 1-2 Gyr, while space missions can detect stars as old as the Galactic disk. In comparison with other techniques for measuring the ages of lower main sequence stars, including geometric parallax and asteroseismology, rotation-based ages have the potential to be the most precise chronometer for 0.6-1.0 M ⊙ stars.

  13. Influence of exposure to electromagnetic field on the cardiovascular system.

    PubMed

    Jeong, J H; Kim, J S; Lee, B C; Min, Y S; Kim, D S; Ryu, J S; Soh, K S; Seo, K M; Sohn, U D

    2005-01-01

    1 We examined whether extremely low frequency electromagnetic fields (ELF-EMF) affect the basal level of cardiovascular parameters and influence of drugs acting on the sympathetic nervous system. 2 Male rats were exposed to sham control and EMF (60 Hz, 20 G) for 1 (MF-1) or 5 days (MF-5). We evaluated the alterations of blood pressure (BP), pulse pressure (PP), heart rate (HR), and the PR interval, QRS interval and QT interval on the electrocardiogram and dysrhythmic ratio in basal level and dysrhythmia induced by beta-adrenoceptor agonists. 3 In terms of the basal levels, there were no statistically significant differences among control, MF-1 and MF-5 in PR interval, QRS interval, mean BP, HR and PP. However, the QT interval, representing ventricular repolarization, was significantly reduced by MF-1 (P < 0.05). 4 (-)-Dobutamine (beta1-adrenoceptor-selective agonist)-induced tachycardia was significantly suppressed by ELF-EMF exposure in MF-1 for the increase in HR (DeltaHR), the decrease in QRS interval (DeltaQRS) and the decrease in QT (DeltaQT) interval. Adrenaline (nonselective beta-receptor agonist)-induced dysrhythmia was also significantly suppressed by ELF-EMF in MF-1 for the number of missing beats, the dysrhythmic ratio, and the increase in BP and PP. 5 These results indicated that 1-day exposure to ELF-EMF (60 Hz, 20 G) could suppress the increase in HR by affecting ventricular repolarization and may have a down-regulatory effect on responses of the cardiovascular system induced by sympathetic agonists.

  14. The effects of exposure to electromagnetic field on rat myocardium.

    PubMed

    Kiray, Amac; Tayefi, Hamid; Kiray, Muge; Bagriyanik, Husnu Alper; Pekcetin, Cetin; Ergur, Bekir Ugur; Ozogul, Candan

    2013-06-01

    Exposure to electromagnetic fields (EMFs) causes increased adverse effects on biological systems. The aim of this study was to investigate the effects of EMF on heart tissue by biochemical and histomorphological evaluations in EMF-exposed adult rats. In this study, 28 male Wistar rats weighing 200-250 g were used. The rats were divided into two groups: sham group (n = 14) and EMF group (n = 14). Rats in sham group were exposed to same conditions as the EMF group except the exposure to EMF. Rats in EMF group were exposed to a 50-Hz EMF of 3 mT for 4 h/day and 7 days/week for 2 months. After 2 months of exposure, rats were killed; the hearts were excised and evaluated. Determination of oxidative stress parameters was performed spectrophotometrically. To detect apoptotic cells, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining and caspase-3 immunohistochemistry were performed. In EMF-exposed group, levels of lipid peroxidation significantly increased and activities of superoxide dismutase and glutathione peroxidase decreased compared with sham group. The number of TUNEL-positive cells and caspase-3 immunoreactivity increased in EMF-exposed rats compared with sham. Under electron microscopy, there were mitochondrial degeneration, reduction in myofibrils, dilated sarcoplasmic reticulum and perinuclear vacuolization in EMF-exposed rats. In conclusion, the results show that the exposure to EMF causes oxidative stress, apoptosis and morphologic damage in myocardium of adult rats. The results of our study indicate that EMF-related changes in rat myocardium could be the result of increased oxidative stress. Further studies are needed to demonstrate whether the exposure to EMF can induce adverse effects on myocardium.

  15. Effect of Mobile Phone Radiofrequency Electromagnetic Fields on.

    PubMed

    Umar, Z U; Abubakar, M B; Ige, J; Igbokwe, U V; Mojiminiyi, F B O; Isezuo, S A

    2014-12-29

    Since cell phones emit radiofrequency electromagnetic fields (EMFs), this study tested the hypothesis that cell phones placed near the heart may interfere with the electrical rhythm of the heart or affect the blood pressure. Following informed consent, eighteen randomly selected apparently healthy male volunteers aged 21.44 ± 0.53 years had their blood pressure, pulse rates and ECG measured before and after acute exposure to a cell phone. The ECG parameters obtained were: heart rate (HR), QRS complex duration (QRS), PR interval (PR) and Corrected QT interval (QTc). Results are presented as mean ± SEM. Statistical analyses were done using two-tailed paired t test for blood pressure and pulse rate data and one way ANOVA with a post hoc Tukey test for the ECG data. P<0.05 was considered statistically significant. The blood pressure and pulse rates before and after exposure to the cell phone showed no significant difference. The ECG parameters (HR: beats/min, QRS:ms, PR:ms and QTc respectively) did not differ before (66.33 ± 2.50, 91.78 ± 1.36, 151.67 ± 5.39 and 395.44 ± 4.96), during (66.33 ± 2.40, 91.11 ± 1.61, 153.67 ± 5.06 and 394.33 ± 4.05) and after calls (67.22 ± 2.77, 91.11 ± 1.67, 157.44 ± 4.46 and 396.56 ± 4.93) compared to baseline (67.17 ± 2.19, 94.33 ± 1.57, 150.56 ± 4.93 and 399.56 ± 3.88). These results suggest that acute exposure to EMFs from cell phones placed near the heart may not interfere with the electrical activity of the heart or blood pressure in healthy individuals.

  16. Statistical analysis of personal radiofrequency electromagnetic field measurements with nondetects.

    PubMed

    Röösli, Martin; Frei, Patrizia; Mohler, Evelyn; Braun-Fahrländer, Charlotte; Bürgi, Alfred; Fröhlich, Jürg; Neubauer, Georg; Theis, Gaston; Egger, Matthias

    2008-09-01

    Exposimeters are increasingly applied in bioelectromagnetic research to determine personal radiofrequency electromagnetic field (RF-EMF) exposure. The main advantages of exposimeter measurements are their convenient handling for study participants and the large amount of personal exposure data, which can be obtained for several RF-EMF sources. However, the large proportion of measurements below the detection limit is a challenge for data analysis. With the robust ROS (regression on order statistics) method, summary statistics can be calculated by fitting an assumed distribution to the observed data. We used a preliminary sample of 109 weekly exposimeter measurements from the QUALIFEX study to compare summary statistics computed by robust ROS with a naïve approach, where values below the detection limit were replaced by the value of the detection limit. For the total RF-EMF exposure, differences between the naïve approach and the robust ROS were moderate for the 90th percentile and the arithmetic mean. However, exposure contributions from minor RF-EMF sources were considerably overestimated with the naïve approach. This results in an underestimation of the exposure range in the population, which may bias the evaluation of potential exposure-response associations. We conclude from our analyses that summary statistics of exposimeter data calculated by robust ROS are more reliable and more informative than estimates based on a naïve approach. Nevertheless, estimates of source-specific medians or even lower percentiles depend on the assumed data distribution and should be considered with caution.

  17. Rotating and binary relativistic stars with magnetic field

    NASA Astrophysics Data System (ADS)

    Markakis, Charalampos

    We develop a geometrical treatment of general relativistic magnetohydrodynamics for perfectly conducting fluids in Einstein--Maxwell--Euler spacetimes. The theory is applied to describe a neutron star that is rotating or is orbiting a black hole or another neutron star. Under the hypotheses of stationarity and axisymmetry, we obtain the equations governing magnetohydrodynamic equilibria of rotating neutron stars with poloidal, toroidal or mixed magnetic fields. Under the hypothesis of an approximate helical symmetry, we obtain the first law of thermodynamics governing magnetized equilibria of double neutron star or black hole - neutron star systems in close circular orbits. The first law is written as a relation between the change in the asymptotic Noether charge deltaQ and the changes in the area and electric charge of black holes, and in the vorticity, baryon rest mass, entropy, charge and magnetic flux of the magnetofluid. In an attempt to provide a better theoretical understanding of the methods used to construct models of isolated rotating stars and corotating or irrotational binaries and their unexplained convergence properties, we analytically examine the behavior of different iterative schemes near a static solution. We find the spectrum of the linearized iteration operator and show for self-consistent field methods that iterative instability corresponds to unstable modes of this operator. On the other hand, we show that the success of iteratively stable methods is due to (quasi-)nilpotency of this operator. Finally, we examine the integrability of motion of test particles in a stationary axisymmetric gravitational field. We use a direct approach to seek nontrivial constants of motion polynomial in the momenta---in addition to energy and angular momentum about the symmetry axis. We establish the existence and uniqueness of quadratic constants and the nonexistence of quartic constants for stationary axisymmetric Newtonian potentials with equatorial symmetry

  18. Growth and Transverse Field Muon Spin Rotation of Cobalt Niobate

    NASA Astrophysics Data System (ADS)

    Munsie, Timothy; Millington, Anna; Marjerrison, Casey; Medina, Teresa; Wilson, Murray; Kermarrec, Edwin; Liu, Lian; Dabkowska, Hanna; Uemura, Yasutomo; Williams, Travis; Luke, Graeme

    2014-03-01

    Cobalt niobate, CoNb2O6, is a material whose spins, when in a transverse field, act like the theoretical ideal 1D-Ising model. This occurs due to the magnetic spins aligning highly anisotropically along the Co2+ chains. Because of this unique structure and material performance, the creation and characterization of this material is of both experimental and theoretical interest. The research we will present is a detailing of changes in the characteristics of the growth of the material utilizing the optical floating zone crystal growth method compared to previous growth parameters and an examination of this material in a moderately high transverse field using the technique of muon spin rotation (μSR). We have determined that the quality of crystals created by the floating zone are highly dependent on the growth parameters utilized (original ceramic shape and rotation rate) and dictate the speed at which the growth can be performed. Transverse Field μSR shows a gradual but significant change to the magnetic structure of the material below 5 K. Second Affiliation: Brockhouse Institute for Materials Research.

  19. Chandrasekhar's relation and stellar rotation in the Kepler field

    SciTech Connect

    Silva, J. R. P.; Soares, B. B.; De Freitas, D. B. E-mail: brauliosoares@uern.br

    2014-11-20

    According to the statistical law of large numbers, the expected mean of identically distributed random variables of a sample tends toward the actual mean as the sample increases. Under this law, it is possible to test the Chandrasekhar's relation (CR), (V) = (π/4){sup –1}(Vsin i), using a large amount of Vsin i and V data from different samples of similar stars. In this context, we conducted a statistical test to check the consistency of the CR in the Kepler field. In order to achieve this, we use three large samples of V obtained from Kepler rotation periods and a homogeneous control sample of Vsin i to overcome the scarcity of Vsin i data for stars in the Kepler field. We used the bootstrap-resampling method to estimate the mean rotations ((V) and (Vsin i)) and their corresponding confidence intervals for the stars segregated by effective temperature. Then, we compared the estimated means to check the consistency of CR, and analyzed the influence of the uncertainties in radii measurements, and possible selection effects. We found that the CR with (sin i) = π/4 is consistent with the behavior of the (V) as a function of (Vsin i) for stars from the Kepler field as there is a very good agreement between such a relation and the data.

  20. Route to Topological Superconductivity via Magnetic Field Rotation.

    PubMed

    Loder, Florian; Kampf, Arno P; Kopp, Thilo

    2015-10-19

    The verification of topological superconductivity has become a major experimental challenge. Apart from the very few spin-triplet superconductors with p-wave pairing symmetry, another candidate system is a conventional, two-dimensional (2D) s-wave superconductor in a magnetic field with a sufficiently strong Rashba spin-orbit coupling. Typically, the required magnetic field to convert the superconductor into a topologically non-trivial state is however by far larger than the upper critical field H(c2), which excludes its realization. In this article, we argue that this problem can be overcome by rotating the magnetic field into the superconducting plane. We explore the character of the superconducting state upon changing the strength and the orientation of the magnetic field and show that a topological state, established for a sufficiently strong out-of-plane magnetic field, indeed extends to an in-plane field orientation. We present a three-band model applicable to the superconducting interface between LaAlO3 and SrTiO3, which should fulfil the necessary conditions to realize a topological superconductor.

  1. Comparison of potential field solutions for Carrington Rotation 2144

    NASA Astrophysics Data System (ADS)

    Hayashi, Keiji; Yang, Shangbin; Deng, Yuagyong

    2016-02-01

    We examined differences among the coronal magnetic field structures derived with the potential field source surface (PFSS) model for Carrington Rotation 2144, from 21 November to 19 December 2013. We used the synoptic maps of solar photospheric magnetic field from four observatories, the Huairou Solar Observing Station (HSOS), Global Oscillation Network Group (GONG), Helioseismic Magnetic Imager (HMI), and Wilcox Solar Observatory (WSO). We tested two smoothing methods, Gaussian and boxcar averaging, and correction of unbalanced net magnetic flux. The solutions of three-dimensional coronal magnetic field are significantly different each other. An open-field region derived with HSOS data agrees best with the corresponding coronal hole observed by Solar Dynamics Observatories/Atmospheric Imaging Assembly, while HMI data yielded best agreements with the near-Earth OMNI database. The GONG data overall gave agreements as good as the HMI. The PFSS calculations using WSO data were least sensitive to the choices we examined in this work. Differences in PFSS solutions using different choices and parameters in smoothing imply that the photospheric magnetic field distributions with size of several degrees at midlatitude and low-latitude regions can be decisive, at least, in the examined period. To better determine the global solar corona, therefore, further evaluation of influences from compact bipolar magnetic field is needed.

  2. Effect of radio frequency waves of electromagnetic field on the tubulin.

    PubMed

    Taghi, Mousavi; Gholamhosein, Riazi; Saeed, Rezayi-Zarchi

    2013-09-01

    Microtubules (MTs) are macromolecular structures consisting of tubulin heterodimers and present in almost every eukaryotic cell. MTs fulfill all conditions for generation of electromagnetic field and are electrically polar due to the electrical polarity of a tubulin heterodimer. The calculated static electric dipole moment of about 1000 Debye makes them capable of being aligned parallel to the applied electromagnetic field direction. In the present study, the tubulin heterodimers were extracted and purified from the rat brains. MTs were obtained by polymerization in vitro. Samples of microtubules were adsorbed in the absence and in the presence of electromagnetic fields with radio frequency of 900 Hz. Our results demonstrate the effect of electromagnetic field with 900 Hz frequency to change the structure of MTs. In this paper, a related patent was used that will help to better understand the studied subject.

  3. Subwavelength confinement of electromagnetic field by guided modes of dielectric micro- and nanowaveguides

    NASA Astrophysics Data System (ADS)

    Zheltikov, A. M.

    2010-04-01

    Regimes enabling the strongest confinement of electromagnetic field by guided modes of dielectric micro- and nanowaveguides are identified. Waveguides of this class are shown to allow a guidance of subwavelength optical beams.

  4. Effect of the Earth's magnetic field spatial distribution on the electromagnetic coupling at the fluid core boundaries for nutations

    NASA Astrophysics Data System (ADS)

    Koot, L.; Dumberry, M.

    2011-12-01

    Nutations are periodic variations in the orientation of the Earth's rotation axis in space. This motion is generated by the gravitational torque applied on the Earth's equatorial bulge by the Moon, the Sun, and the other planets. Because the mantle, the fluid outer core and the solid inner core react differently to the applied torque, the nutation motion is characterized by differential rotations between these three regions. Since the boundaries of the fluid outer core are permeated by a background magnetic field (the geodynamo field), the differential rotation at the fluid core boundaries induces a secondary magnetic field by shear and advection of the background field. The associated electric currents produce Lorentz forces and torques between the outer core, inner core, and mantle, that tend to oppose the differential rotation. A previous study has shown that the magnitude of the electromagnetic (EM) torque is mainly determined by the electrical conductivities on both sides of the outer core boundaries and by the mean RMS strength of the background magnetic field, with the spatial distribution of this magnetic field being unimportant to first order. The goal of the present work is to reassess the role of the magnetic field spatial distribution on the strength of the EM torque using a new model of the EM coupling for nutations that we have recently developed. Our model differs from previous ones in that we use a global approach to describe the induced magnetic field. Moreover, we also include in the torque the contribution from the poloidal component of the induced field, an effect neglected in previous models. In addition, we do not assume a priori that the non-dipolar components of the background magnetic field can be represented by a uniform field with the same power but instead we calculate the torque on the basis of the full geometry of the field. This is particularly important for the poloidal torque as it depends directly on the surface gradient of the

  5. Rotation and magnetic field in the Be star omega Orionis

    NASA Astrophysics Data System (ADS)

    Neiner, C.; Hubert, A.-M.; Frémat, Y.; Floquet, M.; Jankov, S.; Preuss, O.; Henrichs, H. F.; Zorec, J.

    2003-10-01

    omega Ori is a B2IIIe star for which rotational modulation and non-radial pulsations (NRP) have been recently investigated from two independent observational campaigns in 1998 and 1999. Putting the data of these 2 campaigns together, and adding data obtained in 2001, we search for multiperiodicity in the line profile variations and evidence for outbursts. From new spectropolarimetric data obtained at the Télescope Bernard Lyot (TBL, Pic du Midi, France) in 2001 we also measure the Stokes V parameter in the polarised light. We find evidence for the presence of a weak magnetic field in omega Ori sinusoidally varying with a period of 1.29 d. The equivalent widths (EW) of the wind sensitive UV resonance lines also show a variation with the same period, which we identify as the rotational period of the star. We propose an oblique rotator model and derive Bpol =530 +/- 230 G to explain the observations. Moreover, we carry out an abundance analysis and find the star to be N-enriched, a property which is shared with other magnetic stars. We propose omega Ori as the first known classical Be star hosting a magnetic field. Based on observations obtained using the Musicos spectropolarimeter at the Observatoire du Pic du Midi (France), during the MuSiCoS 98 campaign \\citep{neiner}, and by \\cite{balona}. Based on INES data from the International Ultraviolet Explorer (IUE) satellite. Table 7 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/409/275

  6. Calculation of electromagnetic fields in the near-field region of a moving scattering object

    NASA Astrophysics Data System (ADS)

    Vogel, M. H.

    1990-07-01

    The problem of scattering of electromagnetic fields by perfectly conducting, moving objects is solved with the Lorentz transformation and the plane wave formulation. Apart from the physical optics approximation, the solution is exact. The result is subsequently applied to the special case of monostatic reflection by an object that moves slowly with respect to the velocity of light. The result can be used to predict the time dependent reflection from an aircraft that passes the antenna of a proximity fuze, and the optimum fuze algorithm can be selected.

  7. Grounding system analysis in transients programs applying electromagnetic field approach

    SciTech Connect

    Heimbach, M.; Grcev, L.D.

    1997-01-01

    Lightning protection studies of substations and power systems require knowledge of the dynamic behavior of large grounding grids during electromagnetic transients. This paper presents strategies which allow to incorporate complex grounding structures computed using a rigorous electromagnetic model in transients programs. A novel technique for rational function representation of frequency-dependent grounding system impedances in the EMTP is described. An arbitrary number of feeding points can be modeled as mutual coupling is taken into account. Overvoltages throughout electrical power systems and the transient ground potential rise in the surroundings of grounding structures can be computed.

  8. Risks perception of electromagnetic fields in Taiwan: the influence of psychopathology and the degree of sensitivity to electromagnetic fields.

    PubMed

    Tseng, Mei-Chih Meg; Lin, Yi-Ping; Hu, Fu-Chang; Cheng, Tsun-Jen

    2013-11-01

    Little is known about the perceived health risks of electromagnetic fields (EMFs) and factors associated with risk perception in non-Western countries. Psychological conditions and risk perception have been postulated as factors that facilitate the attribution of health complaints to environmental factors. This study investigated people's perceived risks of EMFs and other environmental sources, as well as the relationships between risk perception, psychopathology, and the degree of self-reported sensitivity to EMFs. A total of 1,251 adults selected from a nationwide telephone interviewing system database responded to a telephone survey about the relationships between environmental sources and human health. The interview included questions assessing participants' psychiatric conditions and the presence and degree of sensitivity to EMFs. One hundred and seventy participants were self-identified as having sensitivity to EMFs, and 141 met the criteria for psychiatric conditions without EMF sensitivity. More than half of the survey respondents considered power lines and mobile phone base stations to affect people's health to a big extent. Higher sensitivity to EMFs, psychopathology, being female, being married, more years of education, and having a catastrophic illness had positive associations with perceived risks of EMF-related environmental sources as well as for all environmental sources combined. We observed no moderating effect of psychopathology on the association between degree of sensitivity to EMF and risk perception. Thus, psychopathology had influence on general people's risk perception without having influence on the relationship between people's degree of sensitivity to EMF and risk perception. The plausible explanations are discussed in the text.

  9. Bridgman Growth of Germanium Crystals in a Rotating Magnetic Field

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Schweizer, M.; Cobb, S. D.; Walker, J. S.; Szofran, F. R.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    A series of (100)-oriented gallium-doped germanium crystals have been grown by the Bridgman method and under the influence of a rotating magnetic field (RMF). The RMF has a marked affect on the interface shape, changing it from concave to nearly flat. The onset of time-dependent flow instabilities occurs when the critical magnetic Taylor number is exceeded, and this can be observed by noting the appearance of striations in the grown crystals. The critical magnetic Taylor number is a sensitive function of the aspect ratio and, as the crystal grows under a constant applied magnetic field, the induced striations change from nonperiodic to periodic, undergo a period-doubling transition, and then cease to exist. Also, by pulsing the RMF on and off, it is shown that intentional interface demarcations can be introduced.

  10. Regulation of osteogenic differentiation of human adipose-derived stem cells by controlling electromagnetic field conditions

    PubMed Central

    Kang, Kyung Shin; Hong, Jung Min; Kang, Jo A; Rhie, Jong-Won; Jeong, Young Hun; Cho, Dong-Woo

    2013-01-01

    Many studies have reported that an electromagnetic field can promote osteogenic differentiation of mesenchymal stem cells. However, experimental results have differed depending on the experimental and environmental conditions. Optimization of electromagnetic field conditions in a single, identified system can compensate for these differences. Here we demonstrated that specific electromagnetic field conditions (that is, frequency and magnetic flux density) significantly regulate osteogenic differentiation of adipose-derived stem cells (ASCs) in vitro. Before inducing osteogenic differentiation, we determined ASC stemness and confirmed that the electromagnetic field was uniform at the solenoid coil center. Then, we selected positive (30/45 Hz, 1 mT) and negative (7.5 Hz, 1 mT) osteogenic differentiation conditions by quantifying alkaline phosphate (ALP) mRNA expression. Osteogenic marker (for example, runt-related transcription factor 2) expression was higher in the 30/45 Hz condition and lower in the 7.5 Hz condition as compared with the nonstimulated group. Both positive and negative regulation of ALP activity and mineralized nodule formation supported these responses. Our data indicate that the effects of the electromagnetic fields on osteogenic differentiation differ depending on the electromagnetic field conditions. This study provides a framework for future work on controlling stem cell differentiation. PMID:23306704

  11. Growth of II-VI Solid Solutions in the Presence of a Rotating Magnetic Field

    NASA Technical Reports Server (NTRS)

    Gillies, D. C; Motakef, S.; Dudley, M.; Matyi, R.; Volz, H.

    1999-01-01

    The application of a rotating magnetic field (RMF)in the frequency range 60-400 Hz and field strength of the order of 2-8 mT to crystal growth has received increasing attention in recent years. To take full advantage of the control of fluid flow by the forces applied by the field, the liquid column must be electrically conducting. Also, the application of RMF to the directional solidification of a column of liquid can result in complete mixing in the resultant solid. Thus, the technique of RMF is suited to solvent zones and float zones where the composition of the liquid is more readily controlled. In the work we report on, numerical modeling has been applied to II-VI systems, particularly tellurium based traveling heater techniques (THM). Results for a spectrum of field strengths and acceleration levels will be presented. These show clearly the effects of competing buoyancy forces and electromagnetic stirring. Crystals of cadmium zinc telluride and mercury cadmium telluride have been grown terrestrially from a tellurium solvent zone. The effects of the RMF during these experiments will be demonstrated with micrographs showing etch pits, white beam x-ray synchrotron topographs and triple axis x-ray diffraction.

  12. Radiofrequency-electromagnetic field exposures in kindergarten children.

    PubMed

    Bhatt, Chhavi Raj; Redmayne, Mary; Billah, Baki; Abramson, Michael J; Benke, Geza

    2016-10-19

    The aim of this study was to assess environmental and personal radiofrequency-electromagnetic field (RF-EMF) exposures in kindergarten children. Ten children and 20 kindergartens in Melbourne, Australia participated in personal and environmental exposure measurements, respectively. Order statistics of RF-EMF exposures were computed for 16 frequency bands between 88 MHz and 5.8 GHz. Of the 16 bands, the three highest sources of environmental RF-EMF exposures were: Global System for Mobile Communications (GSM) 900 MHz downlink (82 mV/m); Universal Mobile Telecommunications System (UMTS) 2100MHz downlink (51 mV/m); and GSM 900 MHz uplink (45 mV/m). Similarly, the three highest personal exposure sources were: GSM 900 MHz downlink (50 mV/m); UMTS 2100 MHz downlink, GSM 900 MHz uplink and GSM 1800 MHz downlink (20 mV/m); and Frequency Modulation radio, Wi-Fi 2.4 GHz and Digital Video Broadcasting-Terrestrial (10 mV/m). The median environmental exposures were: 179 mV/m (total all bands), 123 mV/m (total mobile phone base station downlinks), 46 mV/m (total mobile phone base station uplinks), and 16 mV/m (Wi-Fi 2.4 GHz). Similarly, the median personal exposures were: 81 mV/m (total all bands), 62 mV/m (total mobile phone base station downlinks), 21 mV/m (total mobile phone base station uplinks), and 9 mV/m (Wi-Fi 2.4 GHz). The measurements showed that environmental RF-EMF exposure levels exceeded the personal RF-EMF exposure levels at kindergartens.Journal of Exposure Science and Environmental Epidemiology advance online publication, 19 October 2016; doi:10.1038/jes.2016.55.

  13. Electromagnetically Driven Plasma-Field Dynamics in Modified Ionosphere

    NASA Astrophysics Data System (ADS)

    Kochetov, Andrey; Terina, Galina

    Under sounding of an artificial ionospheric turbulence by short probing radio pulses of ordinary polarization the two types of scattered signals were observed: a "caviton" signal (CS) and a "plasma" signal (PS), which appeared with the heating transmitter switching on and disap-peared after its switching off (G.I. Terina J. Atm. Terr. Phys, 57, 1995, 273, Izv. VUZov, Radiofizika, 39, 1998, 203). The scattered signal of PS type was revealed also after the heating switching off. It was called an "aftereffect plasma signal" (AEPS) (G.I. Terina Izv .VUZov, Radiofizika, 43, 2000, 958). This signal had large time and spatial delays and appeared mostly when corresponding PS had envelope fluctuations. The aftereffect phenomenon was expressed at time on CS by amplitude increasing at once after the heating transmitter turning off. The theoretical model of this phenomenon is proposed in and some peculiarities of the aftereffect phenomena of the scattered signals in modified ionospheric plasma are considered and discussed. For theoretical interpretation of the characteristics of CS and AEPS the numerical solution of nonlinear Shrüdinger equation (NSE) with driven extension were carried out in inhomogeneous plasma layer with linear electron density profile (A.V. Kochetov, V.A. Mironov, G.I. Terina, Adv. Space Reseacrh, 29, 2002, 1369) and for the one with prescribed density depletion (and A.V. Kochetov, G.I. Terina, Adv. Space Reseacrh, 38, 2006, 2490). The simulation results obtained for linear inhomogeneous plasma layer and for plasma one with density depletion al-low us to interpret the aftereffect of CS and PS qualitatively. The field amplitude increase at relaxation stage displayed at calculations allows us to interpret of CS aftereffect. The large time delays of AEPS can be explained as a result of powerful radio waves trapping in the forming at the plasma resonance regions density depletions (E. Mjøhus, J. Geophys. Res. 103, 1998, 14711; B. Eliasson and L. Stenflo, J

  14. Amyotrophic lateral sclerosis and occupational exposure to electromagnetic fields

    SciTech Connect

    Davanipour, Z.; Sobel, E.; Bowman, J.D.; Qian, Z.; Will, A.D.

    1997-03-01

    In an hypothesis-generating case-control study of amyotrophic lateral sclerosis, lifetime occupational histories were obtained. The patients (n = 28) were clinic based. The occupational exposure of interest in this report is electromagnetic fields (EMFs). This is the first and so far the only exposure analyzed in this study. Occupational exposure up to 2 years prior to estimated disease symptom onset was used for construction of exposure indices for cases. Controls (n = 32) were blood and nonblood relatives of cases. Occupational exposure for controls was through the same age as exposure for the corresponding cases. Twenty (71%) cases and 28 (88%) controls had at least 20 years of work experience covering the exposure period. The occupational history and task data were used to classify blindly each occupation for each subject as having high, medium/high, medium, medium/low, or low EMF exposure, based primarily on data from an earlier and unrelated study designed to obtain occupational EMF exposure information on workers in ``electrical`` and ``nonelectrical`` jobs. By using the length of time each subject spent in each occupation through the exposure period, two indices of exposure were constructed: total occupational exposure (E{sub 1}) and average occupational exposure (E{sub 2}). For cases and controls with at least 20 years of work experience, the odds ratio (OR) for exposure at the 75th percentile of the E{sub 1} case exposure data relative to minimum exposure was 7.5 (P < 0.02; 95% CI, 1.4--38.1) and the corresponding OR for E{sub 2} was 5.5 (P < 0.02; 95% CI, 1.3--22.5). For all cases and controls, the ORs were 2.5 (P < 0.1; 95% CI, 0.9--8.1) for E{sub 1} and 2.3 (P = 0.12; 95% CI, 0.8--6.6) for E{sub 2}. This study should be considered an hypothesis-generating study. Larger studies, using incident cases and improved exposure assessment, should be undertaken.

  15. Rotating-frame gradient fields for magnetic resonance imaging and nuclear magnetic resonance in low fields

    SciTech Connect

    Bouchard, Louis-Serge; Pines, Alexander; Demas, Vasiliki

    2014-01-21

    A system and method for Fourier encoding a nuclear magnetic resonance (NMR) signal is disclosed. A static magnetic field B.sub.0 is provided along a first direction. An NMR signal from the sample is Fourier encoded by applying a rotating-frame gradient field B.sub.G superimposed on the B.sub.0, where the B.sub.G comprises a vector component rotating in a plane perpendicular to the first direction at an angular frequency .omega.in a laboratory frame. The Fourier-encoded NMR signal is detected.

  16. Transient effect of weak electromagnetic fields on calcium ion concentration in Arabidopsis thaliana

    PubMed Central

    Pazur, Alexander; Rassadina, Valentina

    2009-01-01

    Background Weak magnetic and electromagnetic fields can influence physiological processes in animals, plants and microorganisms, but the underlying way of perception is poorly understood. The ion cyclotron resonance is one of the discussed mechanisms, predicting biological effects for definite frequencies and intensities of electromagnetic fields possibly by affecting the physiological availability of small ions. Above all an influence on Calcium, which is crucial for many life processes, is in the focus of interest. We show that in Arabidopsis thaliana, changes in Ca2+-concentrations can be induced by combinations of magnetic and electromagnetic fields that match Ca2+-ion cyclotron resonance conditions. Results An aequorin expressing Arabidopsis thaliana mutant (Col0-1 Aeq Cy+) was subjected to a magnetic field around 65 microtesla (0.65 Gauss) and an electromagnetic field with the corresponding Ca2+ cyclotron frequency of 50 Hz. The resulting changes in free Ca2+ were monitored by aequorin bioluminescence, using a high sensitive photomultiplier unit. The experiments were referenced by the additional use of wild type plants. Transient increases of cytosolic Ca2+ were observed both after switching the electromagnetic field on and off, with the latter effect decreasing with increasing duration of the electromagnetic impact. Compared with this the uninfluenced long-term loss of bioluminescence activity without any exogenic impact was negligible. The magnetic field effect rapidly decreased if ion cyclotron resonance conditions were mismatched by varying the magnetic fieldstrength, also a dependence on the amplitude of the electromagnetic component was seen. Conclusion Considering the various functions of Ca2+ as a second messenger in plants, this mechanism may be relevant for perception of these combined fields. The applicability of recently hypothesized mechanisms for the ion cyclotron resonance effect in biological systems is discussed considering it's operating at

  17. Magnetic Field Effect on the Stability of Flow Induced by a Rotating Magnetic Field

    NASA Technical Reports Server (NTRS)

    Mazuruk, K.; Volz, M. P.; Gillies, D. C.

    1999-01-01

    A linear stability analysis has been performed for the flow induced by a rotating magnetic field in a cylindrical column filled with electrically conducting fluid. The first transition is time- independent and results in the generation of Taylor vortices. The critical value of the magnetic Taylor number has been examined as a function of the strength of the transverse rotating magnetic field, the strength of an axial static magnetic field, and thermal buoyancy. Increasing the transverse field increases the critical magnetic Taylor number and decreases the aspect ratio of the Taylor vortices at the onset of instability. An increase in the axial magnetic field also increases the critical magnetic Taylor number but increases the aspect ratio of the Taylor vortices. Thermal buoyancy is found to have only a negligible effect on the onset of instability.

  18. Magnetic Field Effect on the Stability of Flow Induced by a Rotating Magnetic Field

    NASA Technical Reports Server (NTRS)

    Mazuruk, K.; Gillies, D. C.; Volz, M. P.

    1999-01-01

    A linear stability analysis has been performed for the flow induced by a rotating magnetic field in a cylindrical column filled with electrically conducting fluid. The first transition is time-independent and results in the generation of Taylor vortices. The critical value of the magnetic Taylor number has been examined as a function of the strength of the transverse rotating magnetic field, the strength of an axial static magnetic field, and thermal buoyancy. Increasing the transverse field increases the critical magnetic Taylor number and decreases the aspect ratio of the Taylor vortices at the onset of instability. An increase in the axial magnetic field also increases the critical magnetic Taylor number but increases the aspect ratio of the Taylor vortices. Thermal buoyancy is found to have only a negligible effect on the onset of instability.

  19. Influence of electric, magnetic, and electromagnetic fields on the circadian system: current stage of knowledge.

    PubMed

    Lewczuk, Bogdan; Redlarski, Grzegorz; Zak, Arkadiusz; Ziółkowska, Natalia; Przybylska-Gornowicz, Barbara; Krawczuk, Marek

    2014-01-01

    One of the side effects of each electrical device work is the electromagnetic field generated near its workplace. All organisms, including humans, are exposed daily to the influence of different types of this field, characterized by various physical parameters. Therefore, it is important to accurately determine the effects of an electromagnetic field on the physiological and pathological processes occurring in cells, tissues, and organs. Numerous epidemiological and experimental data suggest that the extremely low frequency magnetic field generated by electrical transmission lines and electrically powered devices and the high frequencies electromagnetic radiation emitted by electronic devices have a potentially negative impact on the circadian system. On the other hand, several studies have found no influence of these fields on chronobiological parameters. According to the current state of knowledge, some previously proposed hypotheses, including one concerning the key role of melatonin secretion disruption in pathogenesis of electromagnetic field induced diseases, need to be revised. This paper reviews the data on the effect of electric, magnetic, and electromagnetic fields on melatonin and cortisol rhythms-two major markers of the circadian system as well as on sleep. It also provides the basic information about the nature, classification, parameters, and sources of these fields.

  20. Influence of Electric, Magnetic, and Electromagnetic Fields on the Circadian System: Current Stage of Knowledge

    PubMed Central

    Żak, Arkadiusz

    2014-01-01

    One of the side effects of each electrical device work is the electromagnetic field generated near its workplace. All organisms, including humans, are exposed daily to the influence of different types of this field, characterized by various physical parameters. Therefore, it is important to accurately determine the effects of an electromagnetic field on the physiological and pathological processes occurring in cells, tissues, and organs. Numerous epidemiological and experimental data suggest that the extremely low frequency magnetic field generated by electrical transmission lines and electrically powered devices and the high frequencies electromagnetic radiation emitted by electronic devices have a potentially negative impact on the circadian system. On the other hand, several studies have found no influence of these fields on chronobiological parameters. According to the current state of knowledge, some previously proposed hypotheses, including one concerning the key role of melatonin secretion disruption in pathogenesis of electromagnetic field induced diseases, need to be revised. This paper reviews the data on the effect of electric, magnetic, and electromagnetic fields on melatonin and cortisol rhythms—two major markers of the circadian system as well as on sleep. It also provides the basic information about the nature, classification, parameters, and sources of these fields. PMID:25136557

  1. Lie algebraic approach to the time-dependent quantum general harmonic oscillator and the bi-dimensional charged particle in time-dependent electromagnetic fields

    SciTech Connect

    Ibarra-Sierra, V.G.; Sandoval-Santana, J.C.; Cardoso, J.L.; Kunold, A.

    2015-11-15

    We discuss the one-dimensional, time-dependent general quadratic Hamiltonian and the bi-dimensional charged particle in time-dependent electromagnetic fields through the Lie algebraic approach. Such method consists in finding a set of generators that form a closed Lie algebra in terms of which it is possible to express a quantum Hamiltonian and therefore the evolution operator. The evolution operator is then the starting point to obtain the propagator as well as the explicit form of the Heisenberg picture position and momentum operators. First, the set of generators forming a closed Lie algebra is identified for the general quadratic Hamiltonian. This algebra is later extended to study the Hamiltonian of a charged particle in electromagnetic fields exploiting the similarities between the terms of these two Hamiltonians. These results are applied to the solution of five different examples: the linear potential which is used to introduce the Lie algebraic method, a radio frequency ion trap, a Kanai–Caldirola-like forced harmonic oscillator, a charged particle in a time dependent magnetic field, and a charged particle in constant magnetic field and oscillating electric field. In particular we present exact analytical expressions that are fitting for the study of a rotating quadrupole field ion trap and magneto-transport in two-dimensional semiconductor heterostructures illuminated by microwave radiation. In these examples we show that this powerful method is suitable to treat quadratic Hamiltonians with time dependent coefficients quite efficiently yielding closed analytical expressions for the propagator and the Heisenberg picture position and momentum operators. -- Highlights: •We deal with the general quadratic Hamiltonian and a particle in electromagnetic fields. •The evolution operator is worked out through the Lie algebraic approach. •We also obtain the propagator and Heisenberg picture position and momentum operators. •Analytical expressions for a

  2. Simple and effective monitoring of the electromagnetic field in the smart cities arena

    NASA Astrophysics Data System (ADS)

    Ares-Pena, Francisco J.; Franceschetti, Giorgio; Iodice, Antonio; Salas-Sánchez, Aarón A.

    2016-08-01

    A simple and economical method for monitoring the electromagnetic field intensity in built-up areas is presented. The method is based on the measurement of the field level over a limited number of points at street level in the city and their transmission to an operative control center, where the field values all over the city are correctly interpolated in real time. Citizens might obtain these values at their sites, via Internet, or by connecting with a dedicated call center. Numerical evaluations of the electromagnetic field intensity via the new developed model and confirming experimental results are finally presented.

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

    PubMed

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

    2012-01-01

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

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

    PubMed Central

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

    2012-01-01

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

  5. Arc Deflection Length Affected by Transverse Rotating Magnetic Field with Lateral Gas

    NASA Astrophysics Data System (ADS)

    Shiino, Toru; Ishii, Yoko; Yamamoto, Shinji; Iwao, Toru; High Current Energy Laboratory (HiCEL) Team

    2016-10-01

    Gas metal arc welding using shielding gas is often used in the welding industry. However, the arc deflection affected by lateral gas is problem because of inappropriate heat transfer. Shielding gas is used in order to prevent the instability affected by the arc deflection. However, the shielding gas causes turbulence, then blowhole of weld defect occurs because the arc affected by the instability is contaminated by the air. Thus, the magnetic field is applied to the arc in order to stabilize the arc using low amount of shielding gas. The method of applying the transverse rotating magnetic field (RMF) to the arc is one of the methods to prevent the arc instability. The RMF drives the arc because of electromagnetic force. The driven arc is considered to be prevented to arc deflection of lateral gas because the arc is restrained by the magnetic field because of the driven arc. In addition, it is assume the RMF prevented to the arc deflection of lateral gas from the multiple directions. In this paper, the arc deflection length affected by the RMF with lateral gas was elucidated in order to know the effect of the RMF for arc stabilization. Specifically, the arc deflection length affected by the magnetic frequency and the magnetic flux density is measured by high speed video camera. As a result, the arc deflection length decreases with increasing magnetic frequency, and the arc deflection length increases with increasing the magnetic flux density.

  6. Bridgman Growth of Germanium Crystals in a Rotating Magnetic Field

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Szofran, F. R.; Cobb, S. D.; Schweizer, M.; Walker, J. S.

    2005-01-01

    A series of (100)-oriented gallium-doped germanium crystals has been grown by the vertical Bridgman method and under the influence of a rotating magnetic field (RMF). Time-dependent flow instabilities occur when the critical magnetic Taylor number (Tm(sup c)) is exceeded, and this can be observed by noting the appearance of striations in the grown crystals. Tm(sup c) decreases as the aspect ratio of the melt increases, and approaches the theoretical limit expected for an infinite cylinder. Intentional interface demarcations are introduced by pulsing the RMF on and off The RMF has a marked affect on the interface shape, changing it from concave to nearly flat as the RMF strength is increased.

  7. Bridgman Growth of Germanium Crystals in a Rotating Magnetic Field

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Walker, J. S.; Schweizer, M.; Cobb, S. D.; Szofran, F. R.

    2004-01-01

    A series of (100)-oriented gallium-doped germanium crystals have been grown by the Bridgman method and under the influence of a rotating magnetic field (RMF). Time-dependent flow instabilities occur when the critical magnetic Taylor number (Tm(sup c) is exceeded, and this can be observed by noting the appearance of striations in the grown crystals. The experimental data indicate that Tm(sup c) increases as the aspect ratio of the melt decreases. Modeling calculations predicting Tm(sup c) as a function of aspect ratio are in reasonable agreement with the experimental data. The RMF has a marked affect on the interface shape, changing it from concave to nearly flat as the RMF strength is increased. Also, by pulsing the RMF on and off, it is shown that intentional interface demarcations can be introduced.

  8. Rotating dipole and quadrupole field for a multiple cathode system

    SciTech Connect

    Chang, X.; Ben-Zvi, I.; Kewisch, J.; Litvinenko, V.; Meng, W.; Pikin, A.; Ptitsyn, V.; Rao, T.; Sheehy, B.; Skarita, J.; Wang, E.; Wu, Q.; Xin, T.

    2011-03-28

    A multiple cathode system has been designed to provide the high average current polarized electron bunches for the future electron-ion collider eRHIC [1]. One of the key research topics in this design is the technique to generate a combined dipole and quadrupole rotating field at high frequency (700 kHz). This type of field is necessary for combining bunches from different cathodes to the same axis with minimum emittance growth. Our simulations and the prototype test results to achieve this will be presented. The future eRHIC project, next upgrade of EHIC, will be the first electron-heavy ion collider in the world. For polarized-electron and polarized proton collisions, it requires a polarized electron source with high average current ({approx}50 mA), short bunch ({approx}3 mm), emittance of about 20 {micro}m and energy spread of {approx}1% at 10 MeV. The state-of-art polarized electron cathode can generate average current of about more than 1 mA, but much less than 50 mA. The current is limited by the quantum efficiency, lifetime, space charge and ultra-high vacuum requirement of the polarized cathode. A possible approach to achieve the 50 mA beam is to employ multiple cathodes, such as 20 cathodes, and combine the multiple bunched beams from cathodes to the same axis. We name it as 'Gatling gun' because its operations bear similarity to a multi-barrel Gatling gun. The electron spin direction is not affected by electric field but will follow to the direction of the magnetic bending. This requires that, to preserve the spin polarization from cathode, the fixed bending field after the solenoid and the rotating bending field in combiner must be either a pair of electric bendings or a pair of magnetic bendings. We choose the scheme with a pair of magnetic bendings because it is much easier than the scheme with a pair of electric bendings at our 200 keV electron energy level.

  9. Electromagnetic Near Field Measurements of Two Critical Assemblies

    SciTech Connect

    Goettee, Jeffrey David

    2015-11-03

    The reactors employed, Godiva IV and WSMR Fast Burst Reactor, are described first. Then the point reactor kinetics model, electromagnetic potential, and the measurement of kinetics quantities are successively discussed. In summary, reactor power produces measurable electric energy. The electric signal mimics power curve for prompt burst operations - features in logarithmic derivatives match. The electric signature should be dependent on the power and not the derivative; therefore, steady-state modes should be measurable.

  10. Radiation of electromagnetic waves by a dipole in an external uniform electrostatic field

    NASA Astrophysics Data System (ADS)

    Manaenkov, S. I.

    2017-01-01

    Exact solution for the electromagnetic field densities E and H of a dipole of uniformly accelerated point-charges with identical masses is discussed. It is shown that, for any fixed time t and a large distance R between the center of the dipole and the fieldpoint, | E| R -4, | H| R -5, while for large c| t| R, | E| | H| 1/ R as in spherical electromagnetic waves. Nevertheless, any irreversible radiation of electromagnetic waves is absent since the wave zone does not exist.

  11. Electromagnetic instability in plasmas heated by a laser field.

    PubMed

    Bendib, A; Bendib-Kalache, K; Cros, B; Deutsch, C; Maynard, G

    2017-02-01

    Electromagnetic instability is investigated in homogeneous plasmas heated by a laser wave in the range α=v_{0}^{2}/v_{t}^{2}≤2, where v_{0} is the electron quiver velocity and v_{t} is the thermal velocity. The anisotropic electron distribution function that drives unstable quasistatic electromagnetic modes is calculated numerically with the Vlasov-Landau equation in the high ion charge number approximation. A dispersion relation of electromagnetic waves which accounts for further nonlinear terms on v_{0}^{2} from previous results is derived. In typical simulation with ion charge number Z=13, a temperature T=5keV, a density n=9.8×10^{20}cm^{-3}, and a laser wavelength λ_{laser}=1.06μm, growth rates larger than 10^{12}s^{-1} in the quasicollisionless wave-number range were found for α≥1. In the same physical conditions and in the mildly collisional range a growth rate about 10^{11}s^{-1} was also obtained. The extent of the growth wave-number region increases significantly with increasing α.

  12. Electromagnetic instability in plasmas heated by a laser field

    NASA Astrophysics Data System (ADS)

    Bendib, A.; Bendib-Kalache, K.; Cros, B.; Deutsch, C.; Maynard, G.

    2017-02-01

    Electromagnetic instability is investigated in homogeneous plasmas heated by a laser wave in the range α =v02/vt2≤2 , where v0 is the electron quiver velocity and vt is the thermal velocity. The anisotropic electron distribution function that drives unstable quasistatic electromagnetic modes is calculated numerically with the Vlasov-Landau equation in the high ion charge number approximation. A dispersion relation of electromagnetic waves which accounts for further nonlinear terms on v02 from previous results is derived. In typical simulation with ion charge number Z =13 , a temperature T =5 keV , a density n =9.8 ×1020c m-3 , and a laser wavelength λlaser=1.06 μ m , growth rates larger than 1012s-1 in the quasicollisionless wave-number range were found for α ≥1 . In the same physical conditions and in the mildly collisional range a growth rate about 1011s-1 was also obtained. The extent of the growth wave-number region increases significantly with increasing α .

  13. Rotation of solar magnetic fields for the current solar cycle 24

    SciTech Connect

    Shi, X. J.; Xie, J. L.

    2014-11-01

    The rotation of solar magnetic fields for the current solar cycle 24 is investigated through a cross-correlation analysis of the Carrington synoptic maps of solar photospheric magnetic fields during Carrington rotation numbers 2076-2146 (2008 October to 2014 January). The sidereal rotation rates of positive and negative magnetic fields at some latitudes are shown, and it can be found that the positive (negative) fields generally rotate faster than the negative (positive) fields in the southern (northern) hemisphere at low latitudes. The mean rotation profiles of total, positive, and negative magnetic fields between ±60° latitudes in the time interval are also obtained. It should be noted that both of the mean rotation profiles of the positive and negative magnetic fields, as well as the mean rotation profile of the total magnetic field, exhibit a quasi-rigid rotation at latitudes above about 55°. The mean rotation rates of the positive (negative) polarity reach their maximum values at about 9°(6)° latitude in the southern (northern) hemisphere. The mean rotation profile of the total magnetic field displays an obvious north-south asymmetry, where the rotation seems to be more differential in the northern hemisphere. The latitude variation in the rotation rate differences between positive and negative magnetic fields is further studied, and it is found that magnetic fields with the same polarity as the leading sunspots at a given hemisphere rotate faster than those with the opposite polarity, except for the zones around 52° latitude of the southern hemisphere and around 35° latitude of the northern hemisphere. The implication of these results is discussed. It is clear that the obtained results can provide some observational constraints on the theoretical research of the mechanisms of differential rotation and solar cycle.

  14. [Reaction of the endocrine system to continuous and intermittent electromagnetic fields].

    PubMed

    Zagorskaia, E A

    1989-01-01

    This paper reviews Soviet and foreign data about the effects of low frequency electromagnetic fields of continuous and intermittent generation on the endocrine system of animals and humans. It has been shown that the pituitary-adrenal, pituitary-thyroid and reproductive systems are sensitive to these effects. It is postulated that the endocrine responses to electromagnetic effects are similar to the general adaptive reactions to various pathophysiological exposures.

  15. Classical electromagnetic fields from quantum sources in heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Holliday, Robert; McCarty, Ryan; Peroutka, Balthazar; Tuchin, Kirill

    2017-01-01

    Electromagnetic fields are generated in high energy nuclear collisions by spectator valence protons. These fields are traditionally computed by integrating the Maxwell equations with point sources. One might expect that such an approach is valid at distances much larger than the proton size and thus such a classical approach should work well for almost the entire interaction region in the case of heavy nuclei. We argue that, in fact, the contrary is true: due to the quantum diffusion of the proton wave function, the classical approximation breaks down at distances of the order of the system size. We compute the electromagnetic field created by a charged particle described initially as a Gaussian wave packet of width 1 fm and evolving in vacuum according to the Klein-Gordon equation. We completely neglect the medium effects. We show that the dynamics, magnitude and even sign of the electromagnetic field created by classical and quantum sources are different.

  16. Motion of an Electric Dipole in a Static Electromagnetic Field

    DTIC Science & Technology

    2008-09-01

    Resumen Combinamos expresiones para la fuerza y la torca en un dipolo eléctrico en movimiento en un campo magnetostático con las ocasionadas... circular arc in the +z direction. Associated with these rotational oscillations will be a periodically varying force 8 9 10 11 12 13 14 15 pBτ pBF

  17. The nonextensive parameter for nonequilibrium electron gas in an electromagnetic field

    SciTech Connect

    Yu, Haining; Du, Jiulin

    2014-11-15

    The nonextensive parameter for nonequilibrium electron gas of the plasma in an electromagnetic field is studied. We exactly obtained an expression of the q-parameter based on Boltzmann kinetic theories for plasmas, where Coulombian interactions and Lorentz forces play dominant roles. We show that the q-parameter different from unity is related by an equation to temperature gradient, electric field strength, magnetic induction as well as overall bulk velocity of the gas. The effect of the magnetic field on the q-parameter depends on the overall bulk velocity. Thus the q-parameter for the electron gas in an electromagnetic field represents the nonequilibrium nature or nonisothermal configurations of the plasma with electromagnetic interactions. - Highlights: • An expression of the q-parameter is obtained for nonequilibrium plasma with electromagnetic interactions. • The q-parameter is related to temperature gradient, electric field strength, magnetic induction as well as overall bulk velocity of the plasma. • The q-parameter represents the nonequilibrium nature of the complex plasma with electromagnetic interactions.

  18. Public health risk from ELF (electromagnetic fields) exposure -- can it be assessed

    SciTech Connect

    Aldrich, T.E.; Easterly, C.E.

    1988-01-01

    Extremely low frequency electromagnetic fields (ELF) are a ubiquitous environmental agent. There are persistent indications that these fields have biologic activity, and consequently, there may be a deleterious component to their action. Epidemiologic researchers of ELF face several methodological obstacles, and quantitative risk assessment is in a quandary. Simply stated there is a need for more data---especially with regard to exposure assessment.

  19. Exact Electromagnetic Fields Produced by a Finite Wire with Constant Current

    ERIC Educational Resources Information Center

    Jimenez, J. L.; Campos, I.; Aquino, N.

    2008-01-01

    We solve exactly the problem of calculating the electromagnetic fields produced by a finite wire with a constant current, by using two methods: retarded potentials and Jefimenko's formalism. One result in this particular case is that the usual Biot-Savart law of magnetostatics gives the correct magnetic field of the problem. We also show…

  20. Tools and Setups for Experiments with AC and Rotating Magnetic Fields

    ERIC Educational Resources Information Center

    Ponikvar, D.

    2010-01-01

    A rotating magnetic field is the basis for the transformation of electrical energy to mechanical energy. School experiments on the rotating magnetic field are rare since they require the use of specially prepared mechanical setups and/or relatively large, three-phase power supplies to achieve strong magnetic fields. This paper proposes several…

  1. Molecular based magnets comprising vanadium tetracyanoethylene complexes for shielding electromagnetic fields

    DOEpatents

    Epstein, Arthur J.; Morin, Brian G.

    1998-01-01

    The invention presents a vanadium tetracyanoethylene solvent complex for electromagnetic field shielding, and a method for blocking low frequency and magnetic fields using these vanadium tetracyanoethylene compositions. The compositions of the invention can be produced at ambient temperature and are light weight, low density and flexible. The materials of the present invention are useful as magnetic shields to block low frequency fields and static fields, and for use in cores in transformers and motors.

  2. Molecular based magnets comprising vanadium tetracyanoethylene complexes for shielding electromagnetic fields

    DOEpatents

    Epstein, A.J.; Morin, B.G.

    1998-10-13

    The invention presents a vanadium tetracyanoethylene solvent complex for electromagnetic field shielding, and a method for blocking low frequency and magnetic fields using these vanadium tetracyanoethylene compositions. The compositions of the invention can be produced at ambient temperature and are light weight, low density and flexible. The materials of the present invention are useful as magnetic shields to block low frequency fields and static fields, and for use in cores in transformers and motors. 21 figs.

  3. Magnetic field instability of a plasma in a beam of electromagnetic radiation

    NASA Astrophysics Data System (ADS)

    Gradov, O. M.; Stenflo, L.

    1980-04-01

    A beam of electromagnetic radiation can generate magnetic fields in plasmas. It is shown that those fields grow significantly when the incident radiation is sufficiently strong. We obtain expressions for the characteristic time of the growth of the fields as well as for their spatial distribution and point out a possible mechanism, which can lead to the formation of a quasi-stationary state. The maximum value of the magnetic field strength is estimated.

  4. A study of solidification with a rotating magnetic field

    NASA Astrophysics Data System (ADS)

    Roplekar, Jayant K.

    Due to the drive for weight reduction in the automobile industry, near net shape parts produced by semi-solid processing of aluminum alloys are increasingly replacing traditional steel parts. Magnetohydrodynamic direct chill casting (MHD-DC) process, developed in the mid-eighties, is the method of choice to produce rheocast metal alloys for semi-solid applications. In spite of commercial applicability of the MHD-DC process there is no integrated process model available for this process. In the present work we use an experimental setup that combines directional solidification with magnetic stirring to develop a numerical model for the MHD-DC process. We use the finite element method to solve the coupled equations of turbulent fluid flow, species transport and heat transfer with solidification on a fixed grid. Effects of the rotating magnetic field are incorporated through a body-force term which is determined a priori based on a detailed analytical study and experimental data. Due to the nature of temperature-solute coupling and the advection dominated evolution of the liquid fraction, special numerical procedures had to be implemented in the present work. The numerical procedure used in the present work is validated against two validation problems. In the first validation problem, we apply the two-phase methodology to solve the classical problem of diffusion-dominated solidification. The good agreement between the finite element solution and the analytical solution establishes soundness of the two-phase formulation developed in this work. In the second validation problem, a finite element prediction of the flow induced in a cylindrical cavity due to a rotating magnetic field is compared with an independent spectral solution. The close agreement between two radically different solution procedures establishes the accuracy in the formulation and implementation of the both procedures. We then simulate the experiments using the numerical model. The numerical model

  5. Broadband field enhancement of THz electromagnetic wave by surface-textured micron PVDF cylinders

    NASA Astrophysics Data System (ADS)

    Li, Xinxin; Liu, Xuan; Zhang, Luoning; Zhou, Jing; Liu, Dahe

    2015-07-01

    A cylindrical dimmer system is proposed to realize broadband field enhancement for terahertz (THz) electromagnetic wave. A surface-textured crescent-shaped cylinder is proposed to red-shift the absorption spectrum comparing to the traditional crescent-shaped cylinder based on the concept of spoof surface plasmons. Such cylinders made of ferroelectric polyvinylidene fluoride can realize the electromagnetic wave harvesting at terahertz frequencies with a broadband and huge absorption cross section. Two such cylinders in close proximity could achieve considerable electromagnetic field enhancement and field confinement in the gap, which could be applied in THz molecules detection, toxic chemical sensing, and safety screening and could break the detection binding that limits the molecules <100 nm.

  6. Chronic prenatal exposure to the 900 megahertz electromagnetic field induces pyramidal cell loss in the hippocampus of newborn rats.

    PubMed

    Bas, O; Odaci, E; Mollaoglu, H; Ucok, K; Kaplan, S

    2009-07-01

    Widespread use of mobile phones which are a major source of electromagnetic fields might affect living organisms. However, there has been no investigation concerning prenatal exposure to electromagnetic fields or their roles in the development of the pyramidal cells of the cornu ammonis in postnatal life. Two groups of pregnant rats, a control group and an experimental group, that were exposed to an electromagnetic field were used. For obtaining electromagnetic field offspring, the pregnant rats were exposed to 900 megahertz electromagnetic fields during the 1-19th gestation days. There were no actions performed on the control group during the same period. The offspring rats were spontaneously delivered--control group (n = 6) and electromagnetic field group (n = 6). Offspring were sacrificed for stereological analyses at the end of the 4th week. Pyramidal cell number in rat cornu ammonis was estimated using the optical fractionator technique. It was found that 900 megahertz of electromagnetic field significantly reduced the total pyramidal cell number in the cornu ammonis of the electromagnetic field group (P < 0.001). Therefore, although its exact mechanism is not clear, it is suggested that pyramidal cell loss in the cornu ammonis could be due to the 900 megahertz electromagnetic field exposure in the prenatal period.

  7. Influence of electromagnetic field intensity on the metastable zone width of CaCO3 crystallization in circulating water

    NASA Astrophysics Data System (ADS)

    Wang, Jianguo; Liang, Yandong; Chen, Si

    2016-09-01

    In this study, changes in the metastable zone width of CaCO3 crystallization was determined through conductivity titration by altering electromagnetic field parameters applied to the circulating water system. The critical conductivity value and metastable zone curves of CaCO3 crystallization were determined under different solution concentrations and electromagnetic field intensities. Experimental results indicate that the effect of the electromagnetic field intensity on the critical conductivity value intensifies with the increase of solution concentration. Moreover, the metastable zone width of CaCO3 crystallization increases with the increase of electromagnetic field intensity within 200 Gs, thereby prolonging the induction period of nucleation.

  8. Particle Production in Strong Electromagnetic Fields in Relativistic Heavy-Ion Collisions

    DOE PAGES

    Tuchin, Kirill

    2013-01-01

    I reviewmore » the origin and properties of electromagnetic fields produced in heavy-ion collisions. The field strength immediately after a collision is proportional to the collision energy and reaches ~ m π 2 at RHIC and ~ 10 m π 2 at LHC. I demonstrate by explicit analytical calculation that after dropping by about one-two orders of magnitude during the first fm/c of plasma expansion, it freezes out and lasts for as long as quark-gluon plasma lives as a consequence of finite electrical conductivity of the plasma. Magnetic field breaks spherical symmetry in the direction perpendicular to the reaction plane, and therefore all kinetic coefficients are anisotropic. I examine viscosity of QGP and show that magnetic field induces azimuthal anisotropy on plasma flow even in spherically symmetric geometry. Very strong electromagnetic field has an important impact on particle production. I discuss the problem of energy loss and polarization of fast fermions due to synchrotron radiation, consider photon decay induced by magnetic field, elucidate J / ψ dissociation via Lorentz ionization mechanism, and examine electromagnetic radiation by plasma. I conclude that all processes in QGP are affected by strong electromagnetic field and call for experimental investigation.« less

  9. Oxidative and genotoxic effects of 900 MHz electromagnetic fields in the earthworm Eisenia fetida.

    PubMed

    Tkalec, Mirta; Stambuk, Anamaria; Srut, Maja; Malarić, Krešimir; Klobučar, Göran I V

    2013-04-01

    Accumulating evidence suggests that exposure to radiofrequency electromagnetic field (RF-EMF) can have various biological effects. In this study the oxidative and genotoxic effects were investigated in earthworms Eisenia fetida exposed in vivo to RF-EMF at the mobile phone frequency (900 MHz). Earthworms were exposed to the homogeneous RF-EMF at field levels of 10, 23, 41 and 120 V m(-1) for a period of 2h using a Gigahertz Transversal Electromagnetic (GTEM) cell. At the field level of 23 V m(-1) the effect of longer exposure (4h) and field modulation (80% AM 1 kHz sinusoidal) was investigated as well. All exposure treatments induced significant genotoxic effect in earthworms coelomocytes detected by the Comet assay, demonstrating DNA damaging capacity of 900 MHz electromagnetic radiation. Field modulation additionally increased the genotoxic effect. Moreover, our results indicated the induction of antioxidant stress response in terms of enhanced catalase and glutathione reductase activity as a result of the RF-EMF exposure, and demonstrated the generation of lipid and protein oxidative damage. Antioxidant responses and the potential of RF-EMF to induce damage to lipids, proteins and DNA differed depending on the field level applied, modulation of the field and duration of E. fetida exposure to 900 MHz electromagnetic radiation. Nature of detected DNA lesions and oxidative stress as the mechanism of action for the induction of DNA damage are discussed.

  10. Orientational dynamics of a ferronematic liquid crystal in a rotating magnetic field

    SciTech Connect

    Boychuk, A. N. Zakhlevnykh, A. N.; Makarov, D. V.

    2015-09-15

    The behavior of the orientational structure of a ferronematic in a rotating uniform magnetic field is investigated using the continual theory. The time-dependent system of equations describing the dynamics of the ferronematic is derived. The dependences of the angles of rotation of the director and of the magnetization of the ferronematic on the velocity of field rotation are determined for various values of the material parameters. Two regimes (synchronous and asynchronous) of rotation of the ferronematic structure are detected. In the synchronous regime, the director rotates with the frequency of the magnetic field and a constant phase delay. The asynchronous regime is characterized by a time-dependent phase delay. The dependence of the critical angular velocity of magnetic field rotation, which determines the boundary between the synchronous and asynchronous regimes, on the magnetic field strength is derived.

  11. Electromagnetic field of a charge intersecting a cold plasma boundary in a waveguide

    SciTech Connect

    Alekhina, Tatiana Yu.; Tyukhtin, Andrey V.

    2011-06-15

    We analyze the electromagnetic field of a charge crossing a boundary between a vacuum and cold plasma in a waveguide. We obtain exact expressions for the field components and the spectral density of the transition radiation. With the steepest descent technique, we investigate the field components. We show that the electromagnetic field has a different structure in a vacuum than in cold plasma. We also develop an algorithm for the computation of the field based on a certain transformation of the integration path. The behavior of the field depending on distance and time and the spectral density depending on frequency are explored for different charge velocities. Some important physical effects are noted. A considerable increase and concentration of the field near the wave front in the plasma is observed for the case of ultrarelativistic particles. In the plasma, the mode envelopes and spectral density show zero points when the charge velocity is within certain limits.

  12. [Patient exposure to electromagnetic fields in magnetic resonance scanners: a review].

    PubMed

    Guibelalde del Castillo, E

    2013-12-01

    The use of non-ionizing electromagnetic fields in the low frequency end of the electromagnetic spectrum and static fields, radiofrequencies (RF), and microwaves is fundamental both in modern communication systems and in diagnostic medical imaging techniques like magnetic resonance imaging (MRI). The proliferation of these applications in recent decades has led to intense activity in developing regulations to guarantee their safety and to the establishment of guidelines and legal recommendations for the public, workers, and patients. In April 2012 it was foreseen that the European Parliament and Council would approve and publish a directive on the minimum health and safety requirements regarding the exposure of workers to the risks arising from electromagnetic fields, which would modify Directive 2004/40/EC. New studies related to the exposure to electromagnetic radiation and its impact on health published in recent years have led to a new postponement, and it is now foreseen that the directive will come into effect in October 2013. One of the most noteworthy aspects of the new version of the directive is the exclusion of the limits of occupational exposure to electromagnetic fields in the clinical use of MRI. In exchange for this exception, physicians and experts in protection against non-ionizing radiation are asked to make additional efforts to train workers exposed to non-ionizing radiation and to establish mechanisms to guarantee the correct application of non-ionizing electromagnetic fields in patients, along similar lines to the principles of justification and optimization established for ionizing radiation. On the basis of the most recently published studies, this article reviews some safety-related aspects to take into account when examining patients with MRI with high magnetic fields.

  13. A spaceborne receiver for measuring electromagnetic field intensity

    NASA Technical Reports Server (NTRS)

    Reich, B. W.; Van Dusen, M. R.; Habib, E. J.

    1973-01-01

    Description of a very accurately controlled receiver for monitoring the electromagnetic radiations in both existing and projected space communication bands. Based on analysis of the existing and projected space communication bands, 108 to 174 MHz, 240 to 478 MHz, and 1535 to 1665 MHz were covered. The receiver achieves accurate control via a digitally tuned synthesizer and a wide range of digital control including frequency band coverage and gain control selection. Digital memory was provided to store 16 separate digital command instructions which can be programmed via a command data link. The receiver provides for transmission to the ground of both a predetection signal and signals in digital format, which in turn, were provided by sampling and analog-to-digital conversions.

  14. Human osteoarthritic chondrocytes exposed to extremely low-frequency electromagnetic fields (ELF) and therapeutic application of musically modulated electromagnetic fields (TAMMEF) systems: a comparative study.

    PubMed

    Corallo, Claudio; Volpi, Nila; Franci, Daniela; Vannoni, Daniela; Leoncini, Roberto; Landi, Giacomo; Guarna, Massimo; Montella, Antonio; Albanese, Antonietta; Battisti, Emilio; Fioravanti, Antonella; Nuti, Ranuccio; Giordano, Nicola

    2013-06-01

    Osteoarthritis (OA) is the most common joint disease, characterized by matrix degradation and changes in chondrocyte morphology and metabolism. Literature reported that electromagnetic fields (EMFs) can produce benefits in OA patients, even if EMFs mechanism of action is debated. Human osteoarthritic chondrocytes isolated from femoral heads were cultured in vitro in bidimensional (2-D) flasks and in three-dimensional (3-D) alginate beads to mimic closely cartilage environment in vivo. Cells were exposed 30 min/day for 2 weeks to extremely low-frequency electromagnetic field (ELF) with fixed frequency (100 Hz) and to therapeutic application of musically modulated electromagnetic field (TAMMEF) with variable frequencies, intensities, and waveforms. Cell viability was measured at days 7 and 14, while healthy-cell density, heavily vacuolized (hv) cell density, and cluster density were measured by light microscopy only for 3-D cultures after treatments. Cell morphology was observed for 2-D and 3-D cultures by transmission electron microscopy (TEM). Chondrocyte exposure to TAMMEF enhances cell viability at days 7 and 14 compared to ELF. Light microscopy analysis showed that TAMMEF enhances healthy-cell density, reduces hv-cell density and clustering, compared to ELF. Furthermore, TEM analysis showed different morphology for 2-D (fibroblast-like) and 3-D (rounded shape) cultures, confirming light microscopy results. In conclusion, EMFs are effective and safe for OA chondrocytes. TAMMEF can positively interfere with OA chondrocytes representing an innovative non-pharmacological approach to treat OA.

  15. Localization from near-source quasi-static electromagnetic fields

    SciTech Connect

    Mosher, John Compton

    1993-09-01

    A wide range of research has been published on the problem of estimating the parameters of electromagnetic and acoustical sources from measurements of signals measured at an array of sensors. In the quasi-static electromagnetic cases examined here, the signal variation from a point source is relatively slow with respect to the signal propagation and the spacing of the array of sensors. As such, the location of the point sources can only be determined from the spatial diversity of the received signal across the array. The inverse source localization problem is complicated by unknown model order and strong local minima. The nonlinear optimization problem is posed for solving for the parameters of the quasi-static source model. The transient nature of the sources can be exploited to allow subspace approaches to separate out the signal portion of the spatial correlation matrix. Decomposition techniques are examined for improved processing, and an adaptation of MUtiple SIgnal Characterization (MUSIC) is presented for solving the source localization problem. Recent results on calculating the Cramer-Rao error lower bounds are extended to the multidimensional problem here. This thesis focuses on the problem of source localization in magnetoencephalography (MEG), with a secondary application to thunderstorm source localization. Comparisons are also made between MEG and its electrical equivalent, electroencephalography (EEG). The error lower bounds are examined in detail for several MEG and EEG configurations, as well as localizing thunderstorm cells over Cape Canaveral and Kennedy Space Center. Time-eigenspectrum is introduced as a parsing technique for improving the performance of the optimization problem.

  16. Dynamics of liquid-crystalline magnetic suspensions in a rotating magnetic field.

    PubMed

    Boychuk, Alexey N; Makarov, Dmitriy V; Zakhlevnykh, Alexander N

    2016-10-01

    We theoretically study the dynamics of the orientational structure of a ferronematic liquid crystal with soft planar coupling between the director and the magnetization in a rotating magnetic field. We determine critical parameters characterizing the boundary between synchronous and asynchronous rotation regimes. We show that the magnetic impurity increases the stability threshold of an asynchronous rotation regime. The critical angular velocity, the angles of the director and the magnetization rotation in each regime of orientational structure rotation are found for rigid planar coupling. We obtain that in weak magnetic fields when the main mechanism of the field influence on a ferronematic liquid crystal is associated with the effect on the magnetic particles, the critical angular velocity is linearly dependent on the field strength, while in strong magnetic fields, when the influence of a field is determined by a diamagnetic mechanism, the critical velocity is quadratically dependent on the field strength.

  17. From static to rotating to conformal static solutions: rotating imperfect fluid wormholes with(out) electric or magnetic field

    NASA Astrophysics Data System (ADS)

    Azreg-Aïnou, Mustapha

    2014-05-01

    We derive a shortcut stationary metric formula for generating imperfect fluid rotating solutions, in Boyer-Lindquist coordinates, from spherically symmetric static ones. We explore the properties of the curvature scalar and stress-energy tensor for all types of rotating regular solutions we can generate without restricting ourselves to specific examples of regular solutions (regular black holes or wormholes). We show through examples how it is generally possible to generate an imperfect fluid regular rotating solution via radial coordinate transformations. We derive rotating wormholes that are modeled as imperfect fluids and discuss their physical properties. These are independent on the way the stress-energy tensor is interpreted. A solution modeling an imperfect fluid rotating loop black hole is briefly discussed. We then specialize to the recently discussed stable exotic dust Ellis wormhole as emerged in a source-free radial electric or magnetic field, and we generate its, conjecturally stable, rotating counterpart. This turns out to be an exotic imperfect fluid wormhole, and we determine the stress-energy tensor of both the imperfect fluid and the electric or magnetic field.

  18. Resonances and circuit theory for the interaction of metallic disks and annuli with an electromagnetic field

    NASA Astrophysics Data System (ADS)

    Chui, S. T.; Du, J. J.; Yau, S. T.

    2014-11-01

    To understand the nature of the electromagnetic resonances of finite metallic surfaces, we formulate a rigorous and rapidly convergent circuit theory for the interaction of a metallic disk and a metallic annulus with an electromagnetic field. Expressions for the current induced and the resonance condition are derived. A new understanding of the nature of the resonances is obtained. For half of the resonances we find a divergent electric field at the edge of the disk, even though it is smooth in shape. For the disk, we compare with previous results using vector spheroidal wave functions and found good agreement for the resonance condition. Our approach can be generalized to other finite surfaces.

  19. Rotation Periods of Wide Binaries in the Kepler Field

    NASA Astrophysics Data System (ADS)

    Janes, K. A.

    2017-01-01

    In a search of proper motion catalogs for common proper motion stars in the field of the Kepler spacecraft I identified 93 likely binary systems. A comparison of their rotation periods is a test of the gyrochronology concept. To find their periods I calculated the autocorrelation function (ACF) of the Kepler mission photometry for each star. In most systems for which good periods can be found, the cooler star has a longer period than the hotter component, in general agreement with models. However, there is a wide range in the gradients of lines connecting binary pairs in a period–color diagram. Furthermore, near the solar color, only a few stars have longer periods than the Sun, suggesting that they, and their cooler companions, are not much older than the Sun. In addition, there is an apparent gap at intermediate periods in the period distribution of the late K and early M stars. Either star formation in this direction has been variable, or stars evolve in period at a non-uniform rate, or some stars evolve more rapidly than others at the same mass. Finally, using the ACF as a measure of the activity level, I found that while the F, G, and early K stars become less active as their periods increase, there is no correlation between period and activity for the mid K to early M stars.

  20. 3-D explosions: a meditation on rotation (and magnetic fields)

    NASA Astrophysics Data System (ADS)

    Wheeler, J. C.

    This is the text of an introduction to a workshop on asymmetric explosions held in Austin in June, 2003. The great progress in supernova research over thirty-odd years is briefly reviewed. The context in which the meeting was called is then summarized. The theoretical success of the intrinsically multidimensional delayed detonation paradigm in explaining the nature of Type Ia supernovae coupled with new techniques of observations in the near IR and with spectropolarimetry promise great advances in understanding binary progenitors, the explosion physics, and the ever more accurate application to cosmology. Spectropolarimetry has also revealed the strongly asymmetric nature of core collapse and given valuable perspectives on the supernova - gamma-ray burst connection. The capability of the magneto-rotational instability to rapidly create strong toroidal magnetic fields in the core collapse ambiance is outlined. This physics may be the precursor to driving MHD jets that play a role in asymmetric supernovae. Welcome to the brave new world of three-dimensional explosions!

  1. Influence of electromagnetic fields on the enzyme activity of rheumatoid synovial fluid cells in vitro.

    PubMed

    Mohamed-Ali, H; Kolkenbrock, H; Ulbrich, N; Sörensen, H; Kramer, K D; Merker, H J

    1994-04-01

    Since positive clinical effects have been observed in the treatment of rheumatoid arthritis with electromagnetic fields of weak strength and low frequency range (magnetic field strength: 70 microT; frequency: 1.36-14.44 Hz), an attempt was made to analyse the effects of these electromagnetic fields on enzyme activity in monolayer cultures of rheumatoid synovial fluid cells after single irradiation of the cultures for 24 hours. We only investigated the matrix metalloproteinases (collagenase, gelatinase, proteinase 24.11 and aminopeptidases). It was found that electromagnetic fields of such a weak strength and low frequency range do not generally have a uniform effect on the activity of the different proteinases in vitro. While aminopeptidases do not show any great changes in activity, the peptidases hydrolysing N(2,4)-dinitrophenyl-peptide exhibit a distinct increase in activity in the late phase in culture medium without fetal calf serum. In the presence of fetal calf serum this effect is not observed and enzyme activity is diminished. Our experiments do not show whether such a phase-bound increase in the activity of proteinases in vitro is only one finding in a much broader range of effects of electromagnetic fields, or whether it is a specific effect of weak pulsed magnetic fields of 285 +/- 33 nT on enzyme activity after single irradiation. This question requires further elucidation.

  2. Association between electromagnetic field exposure and abortion in pregnant women living in Tehran

    PubMed Central

    Abad, Masoumeh; Malekafzali, Hossein; Simbar, Masoumeh; Seyed Mosaavi, Hassan; Merghati Khoei, Effat

    2016-01-01

    Background: Health-related quality of life is affected by electromagnetic field exposure in each person everyday life. However, this is extremely controversial issue. Objective: Investigation of the associations between electromagnetic field exposure and miscarriage among women of Tehran. Materials and Methods: In this longitudinal study, 462 pregnant women with gestational age <12 wks from seven main regions of Tehran city in Iran with similar social and cultural status were participated. Women were interviewed face-to face to collect data. Reproductive information was collected using medical file recorded in those hospitals the subjects had delivery. The measuring device measured electromagnetic waves, Narda safety test solutions with valid calibration date at the entrance door of their houses. Results: A significant likelihood of miscarriage in women who exposed to significant level of electromagnetic wave. However, this association was not confirmed by Wald test. Conclusion: This study may not provide strong or consistent evidence that electromagnetic field exposure is associated or cause miscarriage. This issue may be due to small sample size in this study. PMID:27326421

  3. Exposure of salivary gland cells to low-frequency electromagnetic fields alters polypeptide synthesis.

    PubMed Central

    Goodman, R; Henderson, A S

    1988-01-01

    This study demonstrates that exposure of cells to extremely low-frequency electromagnetic fields can cause measurable changes in protein synthesis. Sciara coprophila salivary gland cells were exposed to five low-frequency (1.5-72 Hz) electromagnetic signals: three signals (1.5, 15, and 72 Hz) produced pulsed asymmetric electromagnetic fields and two signals (60 and 72 Hz) were sinusoidal. Subsequent analyses of two-dimensional gels showed that cell exposure to either type of low-frequency electromagnetic field resulted in both qualitative and quantitative changes in patterns of protein synthesis. Thus, signals producing diverse waveform characteristics induced previously undetectable polypeptides, some of which were signal specific and augmented or suppressed other polypeptides as compared with nonexposed cells. The pattern of polypeptide synthesis differed from that seen with heat shock: only five polypeptides in cells exposed to electromagnetic signals overlap those polypeptides exposed to heat shock, and the suppression of protein synthesis characteristic of heat shock does not occur. Images PMID:3375247

  4. Calculation of the electric field resulting from human body rotation in a magnetic field.

    PubMed

    Cobos Sánchez, Clemente; Glover, Paul; Power, Henry; Bowtell, Richard

    2012-08-07

    A number of recent studies have shown that the electric field and current density induced in the human body by movement in and around magnetic resonance imaging installations can exceed regulatory levels. Although it is possible to measure the induced electric fields at the surface of the body, it is usually more convenient to use numerical models to predict likely exposure under well-defined movement conditions. Whilst the accuracy of these models is not in doubt, this paper shows that modelling of particular rotational movements should be treated with care. In particular, we show that v × B rather than -(v · ∇)A should be used as the driving term in potential-based modelling of induced fields. Although for translational motion the two driving terms are equivalent, specific examples of rotational rigid-body motion are given where incorrect results are obtained when -(v · ∇)A is employed. In addition, we show that it is important to take into account the space charge which can be generated by rotations and we also consider particular cases where neglecting the space charge generates erroneous results. Along with analytic calculations based on simple models, boundary-element-based numerical calculations are used to illustrate these findings.

  5. Realistic exact solution for the exterior field of a rotating neutron star

    NASA Astrophysics Data System (ADS)

    Pachón, Leonardo A.; Rueda, Jorge A.; Sanabria-Gómez, José D.

    2006-05-01

    A new six-parametric, axisymmetric, and asymptotically flat exact solution of Einstein-Maxwell field equations having reflection symmetry is presented. It has arbitrary physical parameters of mass, angular momentum, mass-quadrupole moment, current octupole moment, electric charge, and magnetic dipole, so it can represent the exterior field of a rotating, deformed, magnetized, and charged object; some properties of the closed-form analytic solution such as its multipolar structure, electromagnetic fields, and singularities are also presented. In the vacuum case, this analytic solution is matched to some numerical interior solutions representing neutron stars, calculated by Berti and Stergioulas [E. Berti and N. Stergioulas, Mon. Not. R. Astron. Soc.MNRAA40035-8711 350, 1416 (2004)10.1111/j.1365-2966.2004.07740.x], imposing that the multipole moments be the same. As an independent test of accuracy of the solution to describe exterior fields of neutron stars, we present an extensive comparison of the radii of innermost stable circular orbits (ISCOs) obtained from the Berti and Stergioulas numerical solutions, the Kerr solution [R. P. Kerr, Phys. Rev. Lett.PRLTAO0031-9007 11, 237 (1963)10.1103/PhysRevLett.11.237], the Hartle and Thorne solution [J. B. Hartle and K. S. Thorne, Astrophys. J.ASJOAB0004-637X 153, 807 (1968)10.1086/149707], an analytic series expansion derived by Shibata and Sasaki [M. Shibata and M. Sasaki, Phys. Rev. DPRVDAQ0556-2821 58, 104011 (1998)10.1103/PhysRevD.58.104011], and our exact solution. We found that radii of ISCOs from our solution fits better than others with realistic numerical interior solutions.

  6. Influence of gravitation on the propagation of electromagnetic radiation

    NASA Technical Reports Server (NTRS)

    Mashhoon, B.

    1975-01-01

    The existence of a general helicity-rotation coupling is demonstrated for electromagnetic waves propagating in the field of a slowly rotating body and in the Goedel universe. This coupling leads to differential focusing of circularly polarized radiation by a gravitational field which is detectable for a rapidly rotating collapsed body. The electromagnetic perturbations and their frequency spectrum are given for the Goedel universe. The spectrum of frequencies is bounded from below by the characteristic rotation frequency of the Goedel universe. If the universe were rotating, the differential focusing effect would be extremely small due to the present upper limit on the anisotropy of the microwave background radiation.

  7. Effects of multiple resistive shells and transient electromagnetic torque on the dynamics of mode locking in reversed field pinch plasmas

    NASA Astrophysics Data System (ADS)

    Guo, S. C.; Chu, M. S.

    2002-11-01

    The effects of multiple resistive shells and transient electromagnetic torque on the dynamics of mode locking in the reversed field pinch (RFP) plasmas are studied. Most RFP machines are equipped with one or more metal shells outside of the vacuum vessel. These shells have finite resistivities. The eddy currents induced in each of the shells contribute to the braking electromagnetic (EM) torque which slows down the plasma rotation. In this work we study the electromagnetic torque acting on the plasma (tearing) modes produced by a system of resistive shells. These shells may consist of several nested thin shells or several thin shells enclosed within a thick shell. The dynamics of the plasma mode is investigated by balancing the EM torque from the resistive shells with the plasma viscous torque. Both the steady state theory and the time-dependent theory are developed. The steady state theory is shown to provide an accurate account of the resultant EM torque if (dω/dt)ω-2≪1 and the time scale of interest is much longer than the response (L/R) time of the shell. Otherwise, the transient theory should be adopted. As applications, the steady state theory is used to evaluate the changes of the EM torque response from the resistive shells in two variants of two RFP machines: (1) modification from Reversed Field Experiment (RFX) [Gnesotto et al., Fusion Eng. Des. 25, 335 (1995)] to the modified RFX: both of them are equipped with one thin shell plus one thick shell; (2) modification from Extrap T2 to Extrap T2R [Brunsell et al., Plasma Phys. Controlled Fusion 43, 1457 (2001)]: both of them are equipped with two thin shells. The transient theory has been applied numerically to study the time evolution of the EM torque during the unlocking of a locked tearing mode in the modified RFX.

  8. Spectral degree of coherence of a random three-dimensional electromagnetic field.

    PubMed

    Korotkova, Olga; Wolf, Emil

    2004-12-01

    The complex spectral degree of coherence of a general random, statistically stationary electromagnetic field is introduced in a manner similar to the way it is defined for a beamlike field, namely, by means of Young's interference experiment. Both its modulus and its phase are measurable. We illustrate the definition by applying it to blackbody radiation emerging from a cavity. The results are of particular interest for near-field optics.

  9. [Metrology of pulse modulated electromagnetic fields with diode-type meters].

    PubMed

    Kubacki, Roman; Kieliszek, Jarosław; Sobiech, Jaromir; Puta, Robert

    2007-01-01

    Electromagnetic field meters used for occupational and general public health protection are commonly calibrated in the continuous wave conditions, but a large number of medical devices, mobile base station antennas and radars generate pulse modulated fields. The results of an analysis of additional errors of pulse fields measurements by diode-type meters (EMR 200/300, PMM and MEH) are presented in this paper.

  10. DiPerna-Lions Flow for Relativistic Particles in an Electromagnetic Field

    NASA Astrophysics Data System (ADS)

    Jabin, P.-E.; Masmoudi, N.

    2015-09-01

    We show the existence and uniqueness of a DiPerna-Lions flow for relativistic particles subject to a Lorentz force in an electromagnetic field. The electric and magnetic fields solve the linear Maxwell system in the vacuum but for singular initial conditions which are only in the physical energy space. As the corresponding force field is only in L 2, we have to perform a careful analysis of the cancellations over a trajectory.

  11. Epilepsy and electromagnetic fields: effects of simulated atmospherics and 100-Hz magnetic fields on audiogenic seizure in rats

    NASA Astrophysics Data System (ADS)

    Juutilainen, J.; Björk, E.; Saali, K.

    1988-03-01

    In order to study the possible association between epileptic seizures and natural electromagnetic fields, 32 female audiogenic seizure (AGS)-susceptible rats were exposed to simulated 10 kHz and 28 kHz atmospherics and to a sinusoidally oscillating magnetic field with a frequency of 100 Hz and field strength of 1 A/m. After the electromagnetic exposure, seizures were induced in the rats with a sound stimulus. The severity of the seizure was determined on an ordinal scale, the audiogenic response score (ARS). The time from the beginning of the sound stimulus to the onset of the seizure (seizure latency) and the duration of the convulsion was measured. No differences from the control experiments were found in the experiments with simulated atmospherics, but the 100 Hz magnetic field increased the seizure latency by about 13% ( P<0.02). The results do not support the hypothesis that natural atmospheric electromagnetic signals could affect the onset of epileptic seizures, but they suggest that AGS-susceptible rats may be a useful model for studying the biological effects of electromagnetic fields.

  12. Magnetic healing, quackery, and the debate about the health effects of electromagnetic fields.

    PubMed

    Macklis, R M

    1993-03-01

    Although the biological effects of low-frequency electromagnetic radiation have been studied since the time of Paracelsus, there is still no consensus on whether these effects are physiologically significant. The recent discovery of deposits of magnetite within the human brain as well as recent, highly publicized tort litigation charging adverse effects after exposure to magnetic fields has rekindled the debate. New data suggest that electromagnetic radiation generated from power lines may lead to physiologic effects with potentially dangerous results. Whether these effects are important enough to produce major epidemiologic consequences remains to be established. The assumption of quackery that has attended this subject since the time of Mesmer's original "animal magnetism" investigations continues to hamper efforts to compile a reliable data base on the health effects of electromagnetic fields.

  13. Extremely low frequency electromagnetic field measurements at the Hylaty station and methodology of signal analysis

    NASA Astrophysics Data System (ADS)

    Kulak, Andrzej; Kubisz, Jerzy; Klucjasz, Slawomir; Michalec, Adam; Mlynarczyk, Janusz; Nieckarz, Zenon; Ostrowski, Michal; Zieba, Stanislaw

    2014-06-01

    We present the Hylaty geophysical station, a high-sensitivity and low-noise facility for extremely low frequency (ELF, 0.03-300 Hz) electromagnetic field measurements, which enables a variety of geophysical and climatological research related to atmospheric, ionospheric, magnetospheric, and space weather physics. The first systematic observations of ELF electromagnetic fields at the Jagiellonian University were undertaken in 1994. At the beginning the measurements were carried out sporadically, during expeditions to sparsely populated areas of the Bieszczady Mountains in the southeast of Poland. In 2004, an automatic Hylaty ELF station was built there, in a very low electromagnetic noise environment, which enabled continuous recording of the magnetic field components of the ELF electromagnetic field in the frequency range below 60 Hz. In 2013, after 8 years of successful operation, the station was upgraded by extending its frequency range up to 300 Hz. In this paper we show the station's technical setup, and how it has changed over the years. We discuss the design of ELF equipment, including antennas, receivers, the time control circuit, and power supply, as well as antenna and receiver calibration. We also discuss the methodology we developed for observations of the Schumann resonance and wideband observations of ELF field pulses. We provide examples of various kinds of signals recorded at the station.

  14. Microfabricated sensors for the measurement of electromagnetic fields in biological tissues

    NASA Astrophysics Data System (ADS)

    Monberg, James; Henning, Albert K.

    1995-09-01

    Public awareness of the risks of exposure to electromagnetic radiation has grown over the past ten yeras. The effects of power lines on human and animal health have drawn particular attention. Some longitudinal studies of cancer rates near power lines show a significant correlation, while others show a null result. The studies have suffered from inadequate sensors for the measurement of electromagnetic radiation in vivo. In this work, we describe the design, construction, and testing of electrically passive, microfabricated single-pole antennas and coils. These sensors will be used in vivo to study the effects of electromagnetic radiation on animals. Our testing to date has been limited to in vitro studies of the magnetic field probes. Magnetic field pickup coils were fabricated with up to 100 turns, over a length of up to 1000 micrometers . Measurements were carried out with the sensors in air, and in water of various saline concentrations. Magnetic fields were applied using a Helmholtz coil. Both dc and ac fields were applied. The results indicate that small-area measurements of electromagnetic fields in vitro can be made successfully, provided adequate shielding and amplification are used.

  15. Possible action mechanism of the electromagnetic fields in the liver cancer development: A mathematical proposal

    SciTech Connect

    Jiménez-García, Mónica Noemí; Godina-Nava, Juan José

    2012-02-08

    Currently it is known that electromagnetic field exposure can induce biological changes, although the precise effects and action mechanism of the interaction between the electromagnetic field and biological systems are not well understood. In this work we propose a possible action mechanism, concerning the effect that the extremely low frequency electromagnetic field exposure has on the early stage of liver cancer development. The model is developed studying the phenomena called oxidative stress that it appears after it is applied a carcinogenic agent used to induce hepatic cancer chemically in an experimental animal model. This physical-chemical process involves the movement of magnetic field dependent free charged particles, called free radicals. We will consider the use of the radical pairs theory as a framework, in which we will describe the spin density operator evolution by implementing the stochastic Liouville equation with hyperfine interaction. This describes how the selectivity of the interaction between spin states of the free radicals with the applied electromagnetic field, influences the development of pre-neoplastic lesions in the liver. AIP Publishing is retracting this article due to the substantial use of content in the Results and Conclusions section without proper citation of a previously published paper in Chemical Physics Letters 361 (2012) 219-225. This article is retracted from the scientific record with effect from 15 October 2015.

  16. Possible action mechanism of the electromagnetic fields in the liver cancer development: A mathematical proposal

    NASA Astrophysics Data System (ADS)

    Jiménez-García, Mónica Noemí; Godina-Nava, Juan José

    2012-02-01

    Currently it is known that electromagnetic field exposure can induce biological changes, although the precise effects and action mechanism of the interaction between the electromagnetic field and biological systems are not well understood. In this work we propose a possible action mechanism, concerning the effect that the extremely low frequency electromagnetic field exposure has on the early stage of liver cancer development. The model is developed studying the phenomena called oxidative stress that it appears after it is applied a carcinogenic agent used to induce hepatic cancer chemically in an experimental animal model. This physical-chemical process involves the movement of magnetic field dependent free charged particles, called free radicals. We will consider the use of the radical pairs theory as a framework, in which we will describe the spin density operator evolution by implementing the stochastic Liouville equation with hyperfine interaction. This describes how the selectivity of the interaction between spin states of the free radicals with the applied electromagnetic field, influences the development of pre-neoplastic lesions in the liver. AIP Publishing is retracting this article due to the substantial use of content in the Results and Conclusions section without proper citation of a previously published paper in Chemical Physics Letters 361 (2012) 219-225. This article is retracted from the scientific record with effect from 15 October 2015.

  17. Confinement of Plasma along Shaped Open Magnetic Fields from the Centrifugal Force of Supersonic Plasma Rotation

    SciTech Connect

    Teodorescu, C.; Young, W. C.; Swan, G. W. S.; Ellis, R. F.; Hassam, A. B.; Romero-Talamas, C. A.

    2010-08-20

    Interferometric density measurements in plasmas rotating in shaped, open magnetic fields demonstrate strong confinement of plasma parallel to the magnetic field, with density drops of more than a factor of 10. Taken together with spectroscopic measurements of supersonic ExB rotation of sonic Mach 2, these measurements are in agreement with ideal MHD theory which predicts large parallel pressure drops balanced by centrifugal forces in supersonically rotating plasmas.

  18. The therapeutic effect of a pulsed electromagnetic field on the reproductive patterns of male Wistar rats exposed to a 2.45-GHz microwave field

    PubMed Central

    Kumar, Sanjay; Kesari, Kavindra Kumar; Behari, Jitendra

    2011-01-01

    INTRODUCTION: Environmental exposure to man-made electromagnetic fields has been steadily increasing with the growing demand for electronic items that are operational at various frequencies. Testicular function is particularly susceptible to radiation emitted by electromagnetic fields. OBJECTIVES: This study aimed to examine the therapeutic effects of a pulsed electromagnetic field (100 Hz) on the reproductive systems of male Wistar rats (70 days old). METHODS: The experiments were divided into five groups: microwave sham, microwave exposure (2.45 GHz), pulsed electromagnetic field sham, pulsed electromagnetic field (100 Hz) exposure, and microwave/pulsed electromagnetic field exposure. The animals were exposed for 2 hours/day for 60 days. After exposure, the animals were sacrificed, their sperm was used for creatine and caspase assays, and their serum was used for melatonin and testosterone assays. RESULTS: The results showed significant increases in caspase and creatine kinase and significant decreases in testosterone and melatonin in the exposed groups. This finding emphasizes that reactive oxygen species (a potential inducer of cancer) are the primary cause of DNA damage. However, pulsed electromagnetic field exposure relieves the effect of microwave exposure by inducing Faraday currents. CONCLUSIONS: Electromagnetic fields are recognized as hazards that affect testicular function by generating reactive oxygen species and reduce the bioavailability of androgen to maturing spermatozoa. Thus, microwave exposure adversely affects male fertility, whereas pulsed electromagnetic field therapy is a non-invasive, simple technique that can be used as a scavenger agent to combat oxidative stress. PMID:21876981

  19. Analysis and measurement of the 3D magnetic field in a rotating magnetic field driven FRC

    NASA Astrophysics Data System (ADS)

    Velas, K. M.; Milroy, R. D.

    2012-10-01

    A translatable three-axis probe was installed on TCSU shortly before its shutdown. The probe has 90 windings that simultaneously measure Br, Bθ, and Bz at 30 radial positions. Positioning the probe at multiple axial positions and taking multiple repeatable shots allows for a full r-z map of the magnetic field. Probe measurements are used to calculate the end-shorting torque and the rotating magnetic field (RMF) torque. The torque applied to the plasma is the RMF torque reduced by the shorting torque. An estimate of the plasma resistivity is made based on the steady state balance between the applied torque and the resistive torque. The steady state data from applying a 10 kHz low pass filter used in conjunction with data at the RMF frequency yields a map of the full 3D rotating field structure. Data from even- and odd-parity experiments will be presented. The NIMROD code has been adapted to simulate the TCSU experiment using boundary conditions adjusted to match both even- and odd-parity experimental conditions. A comparison of the n=0 components of the calculated fields to the 3-axis probe measurements shows agreement in the magnetic field structure of the FRC as well as in the jet region.

  20. Electromagnetic field of fractal distribution of charged particles

    SciTech Connect

    Tarasov, Vasily E.

    2005-08-15

    Electric and magnetic fields of fractal distribution of charged particles are considered. The fractional integrals are used to describe fractal distribution. The fractional integrals are considered as approximations of integrals on fractals. Using the fractional generalization of integral Maxwell equation, the simple examples of the fields of homogeneous fractal distribution are considered. The electric dipole and quadrupole moments for fractal distribution are derived.

  1. Guiding and collimating fast electron beam by the quasi-static electromagnetic field array

    SciTech Connect

    Wang, J.; Zhao, Z. Q.; He, W. H.; Dong, K. G.; Wu, Y. C.; Zhu, B.; Zhang, T. K.; Zhang, B.; Zhang, Z. M.; Gu, Y. Q.; Cao, L. H.

    2014-10-15

    A guidance and collimation scheme for fast electron beam in a traverse periodic quasi-static electromagnetic field array is proposed with the semi-analytic method and the particle-in-cell simulation. The sheath electric fields on the surfaces of nanowires and the magnetic fields around the nanowires form a traverse periodic quasi-static electromagnetic field array. Therefore, most of the fast electrons are confined at the nanowire surfaces and transport forward. More importantly, due to the divergent property of the beams, the magnitudes of the generated fields decrease with the target depth. The lateral momenta of the electrons convert into the forward momenta through Lorenz force, and they cannot recover their initial values. Therefore, the fast electrons can be guided and collimated efficiently in the gaps between the nanowires. In our particle-in-cell simulations, the observed guiding efficiency exceeds 80% compared with the reference target.

  2. Assessment of Electromagnetic Fields inside the Communication Module of a Telecom Satellite

    NASA Astrophysics Data System (ADS)

    Birreck, D.; Guida, G.; Marley, D.; Marliani, F.; Marra, S.; Martorelli, V.

    2012-05-01

    The paper describes the evaluation of the internal electromagnetic fields in overmoded regime inside the telecommunications satellite SGEO. The sources taken into account are the leakages due to both the internal high power transmit chains and the external antennas fields coupled to the internal cavities by means of the numerous apertures present in the satellite skin. The evaluation of the antenna fields has been performed using the GTD and the PTD modules of Antenna Design Framework - Electromagnetic Satellite (ADF- EMS). The internal field computation has been performed with IDSOCT, a code integrated in ADF- EMS based on the Oversized Cavity Theory (OCT). All the transfer functions between sources and internal fields have been computed for easier evaluation of possible mitigations.

  3. A study of the electromagnetic characteristics of no-insulation GdBCO racetrack coils under an external magnetic ripple field

    NASA Astrophysics Data System (ADS)

    Choi, Y. H.; Yang, D. G.; Kim, Y. G.; Kim, S. G.; Song, J. B.; Lee, H. G.

    2016-04-01

    Here we report the effect of an external magnetic ripple field on the electromagnetic characteristics of GdBCO racetrack coils being operated with a constant DC current. Two types of GdBCO racetrack coils, one wound without turn-to-turn insulation (NI) and the other wound with Kapton tape (INS), were examined under external ripple fields generated by a permanent magnet mounted on a rotor, which was driven by a separate AC motor. The voltage fluctuations and magnetic field variations were measured with respect to the external ripple field intensity (B ERF), rotating speed, and the operating condition. When the INS and NI coils were exposed to an external ripple field (herein, I op = 80 A, B ERF = 2 mT, and 5 rpm), a voltage fluctuation occurred because a time-varying magnetic field interacted with an electric circuit creating an electromotive force. The peak-to-peak voltage (V pp = 0.29 mV) of the NI coil was ∼1.86 times lower than that (0.54 mV) of the INS coil, because the voltage response of the NI coil lagged behind dB/dt due to the existence of turn-to-turn contact. Furthermore, the V pp of the INS coil increased with increasing B ERF and rotating speed, while those of the NI coil were barely affected due to the delay of electromagnetic induction. In excessive current and ripple field conditions (I op = 1.125 I c, B ERF = 8 mT, and 50 rpm) the INS coil eventually quenched while the NI coil did not, implying that the electromagnetic stability of the NI coil in excessive time-varying field conditions was superior to that of the INS coil.

  4. Electromagnetic Scattered Field Evaluation and Data Compression Using Imaging Techniques

    NASA Technical Reports Server (NTRS)

    Gupta, I. J.; Burnside, W. D.

    1996-01-01

    This is the final report on Project #727625 between The Ohio State University and NASA, Lewis Research Center, Cleveland, Ohio. Under this project, a data compression technique for scattered field data of electrically large targets is developed. The technique was applied to the scattered fields of two targets of interest. The backscattered fields of the scale models of these targets were measured in a ra compact range. For one of the targets, the backscattered fields were also calculated using XPATCH computer code. Using the technique all scattered field data sets were compressed successfully. A compression ratio of the order 40 was achieved. In this report, the technique is described briefly and some sample results are included.

  5. Forced Magnetic Reconnection and Field Penetration of an Externally Applied Rotating Helical Magnetic Field in the TEXTOR Tokamak

    SciTech Connect

    Kikuchi, Y.; Finken, K. H.; Jakubowski, M.; Koslowski, H. R.; Kraemer-Flecken, A.; Lehnen, M.; Liang, Y.; Reiser, D.; Wolf, R. C.; Zimmermann, O.; Bock, M. F. M. de; Jaspers, R.; Matsunaga, G.

    2006-08-25

    The magnetic field penetration process into a magnetized plasma is of basic interest both for plasma physics and astrophysics. In this context special measurements on the field penetration and field amplification are performed by a Hall probe on the dynamic ergodic divertor (DED) on the TEXTOR tokamak and the data are interpreted by a two-fluid plasma model. It is observed that the growth of the forced magnetic reconnection by the rotating DED field is accompanied by a change of the plasma fluid rotation. The differential rotation frequency between the DED field and the plasma plays an important role in the process of the excitation of tearing modes. The momentum input from the rotating DED field to the plasma is interpreted by both a ponderomotive force at the rational surface and a radial electric field modified by an edge ergodization.

  6. Electromagnetic field exposure assessment in Europe radiofrequency fields (10 MHz-6 GHz).

    PubMed

    Gajšek, Peter; Ravazzani, Paolo; Wiart, Joe; Grellier, James; Samaras, Theodoros; Thuróczy, György

    2015-01-01

    Average levels of exposure to radiofrequency (RF) electromagnetic fields (EMFs) of the general public in Europe are difficult to summarize, as exposure levels have been reported differently in those studies in which they have been measured, and a large proportion of reported measurements were very low, sometimes falling below detection limits of the equipment used. The goal of this paper is to present an overview of the scientific literature on RF EMF exposure in Europe and to characterize exposure within the European population. A comparative analysis of the results of spot or long-term RF EMF measurements in the EU indicated that mean electric field strengths were between 0.08 V/m and 1.8 V/m. The overwhelming majority of measured mean electric field strengths were <1 V/m. It is estimated that <1% were above 6 V/m and <0.1% were above 20 V/m. No exposure levels exceeding European Council recommendations were identified in these surveys. Most population exposures from signals of radio and television broadcast towers were observed to be weak because these transmitters are usually far away from exposed individuals and are spatially sparsely distributed. On the other hand, the contribution made to RF exposure from wireless telecommunications technology is continuously increasing and its contribution was above 60% of the total exposure. According to the European exposure assessment studies identified, three population exposure categories (intermittent variable partial body exposure, intermittent variable low-level whole-body (WB) exposure and continuous low-level WB exposure) were recognized by the authors as informative for possible future risk assessment.

  7. Electromagnetic induction in New Zealand: analogue model and field results

    NASA Astrophysics Data System (ADS)

    Chen, J.; Dosso, H. W.; Ingham, M.

    The behaviour of electric and magnetic variations over North Island (New Zealand) is studied with the aid of a laboratory analogue model. The source field frequencies used in the analogue modelling simulate naturally occurring geomagnetic variations of 5-120 min periods. In-phase and quadrature magnetic and electric fields for a selection of traverses for the modelled region of North Island are presented. Since North Island is of a relatively narrow cross-section, the field responses, even for inland locations, are expected to show strongly the effects of the surrounding ocean. The irregular coastlines, as well as the strait between North and South Islands, lead to coastal and inland field anomalies due to induced currents being deflected and channelled to produce localized current densities. The comparison of model results with field station measurements obtained earlier individually by Ingham and by Midha for sites in the northeastern, central, and southern (near Cook Strait) regions of North Island demonstrates the large role the ocean has in the observed field responses. Differences in the model and field results at some sites are expected and should reflect the effects of the local geology and the conductive substructure related to the complex tectonics of the region not simulated in the model.

  8. Effect of non-ionizing electromagnetic field on the alteration of ovarian follicles in rats

    PubMed Central

    Ahmadi, Seyed Shahin; Khaki, Amir Afshin; Ainehchi, Nava; Alihemmati, Alireza; Khatooni, Azam Asghari; Khaki, Arash; Asghari, Ali

    2016-01-01

    Introduction In recent years, there has been an increase in the attention paid to safety effects, environmental and society’s health, extremely low frequency electromagnetic fields (ELF-EMF), and radio frequency electromagnetic fields (RF-EMF). The aim of this research was to determine the effect of EMF on the alteration of ovarian follicles. Methods In this experimental study at Tabriz Medical University in 2015, we did EMF exposures and assessed the alteration of rats’ ovarian follicles. Thirty three-month old rats were selected randomly from laboratory animals, and, after their ages and weights were determined, they were divided randomly into three groups. The control group consisted of 10 rats without any treatment, and they were kept in normal conditions. The second group of rats was influenced by a magnetic field of 50 Hz for eight weeks (three weeks intrauterine and five weeks ectopic). The third group of rats was influenced by a magnetic field of 50 Hz for 13 weeks (three weeks intrauterine and ten weeks ectopic). Samples were fixed in 10% buffered formaldehyde and cleared with Xylol and embedded in paraffin. After sectioning and staining, samples were studied by optic microscopy. Finally, SPSS version 17, were used for data analysis. Results EMF radiation increased the harmful effects on the formation of ovarian follicles and oocytes implantation. Studies on the effects of electromagnetic fields on ovarian follicles have shown that the nuclei of the oocytes become smaller and change shape. There were significant, harmful changes in the groups affected by electromagnetic waves. Atresia of ovarian follicles was significantly significant in both study groups compared to the control group (p < 0.05). Conclusion Exposure to electromagnetic fields during embryonic development can cause morphological changes in oocytes and affect the differentiation of oocytes and folliculogenesis, resulting in decreased ovarian reserve leading to infertility or reduced

  9. Strings: A possible alternative explanation for the Unification of Gravitation Field and Electromagnetic Field

    NASA Astrophysics Data System (ADS)

    Rivera, Susana

    Throughout the last century, since the last decades of the XIX century, until present day, there had been many attempts to achieve the unification of the Forces of Nature. First unification was done by James Clerk Maxwell, with his Electromagnetic Theory. Then Max Plank developed his Quantum Theory. In 1905, Albert Einstein gave birth to the Special Relativity Theory, and in 1916 he came out with his General Relativity Theory. He noticed that there was an evident parallelism between the Gravitational Force, and the Electromagnetic Force. So, he tried to unify these forces of Nature. But Quantum Theory interposed on his way. On the 1940’s it had been developed the Quantum Electrodynamics (QED), and with it, the unified field theory had an arise interest. On the 60’s and 70’s there was developed the Quantum Chromodynamics (QCD). Along with these theories came the discovery of the strong interaction force and weak interaction force. And though there had been many attempts to unify all these forces of the nature, it could only be achieved the Unification of strong interaction, weak interaction and Electromagnetic Force. On the late 80”s and throughout the last two decades, theories such as “super-string theory”, “or the “M-theory”, among others, groups of Scientists, had been doing grand efforts and finally they came out with the unification of the forces of nature, being the only limitation the use of more than 11 dimensions. Using an ingenious mathematical tool known as the super symmetries, based on the Kaluza - Klein work, they achieve this goal. The strings of these theories are in the rank of 10-33 m. Which make them undetectable. There are many other string theories. The GEUFT theory is based on the existence of concentrated energy lines, which vibrates, expands and contracts, submitting and absorbing energy, matter and antimatter, and which yields a determined geometry, that gives as a result the formation of stars, galaxies, nebulae, clusters

  10. Observations of improved confinement in field reversed configurations sustained by antisymmetric rotating magnetic fields

    SciTech Connect

    Guo, H.Y.; Hoffman, A.L.; Steinhauer, L.C.

    2005-06-15

    Rotating magnetic fields (RMF) have been employed to both form and sustain currents in field reversed configurations (FRC). A major concern about this method has been the fear of opening up magnetic field lines with even small ratios of vacuum RMF B{sub {omega}} to external confinement field B{sub e}. A recently proposed innovation was to use an antisymmetric arrangement of RMF, but vacuum calculations with full RMF penetration showed that very low values of B{sub {omega}}/B{sub e} would still be required to provide field-line closure. Recent comparisons of symmetric and antisymmetric RMF drive on the translation, confinement, and sustainment (TCS) facility [A. L. Hoffman, H. Y. Guo, J. T. Slough et al., Fusion Sci. Technol. 41, 92 (2002)] have shown strong improvements in the basic confinement properties of the FRCs when using antisymmetric drive, even with ratios of B{sub {omega}}/B{sub e} as high as 0.3. This is due to normal standard operation with only partial penetration of the RMF beyond the FRC separatrix. The uniform transverse RMF in vacuum is shielded by the conducting plasma, resulting in a mostly azimuthal field near the FRC separatrix with a very small radial component. Simple numerical calculations using analytical solutions for the partially penetrated antisymmetric RMF, superimposed on Grad-Shafranov solutions for the poloidal FRC fields, show good field-line closure for the TCS experimental conditions. The antisymmetric arrangement also leads to more efficient current drive and improved stabilization of rotational modes.

  11. The Role of Angular Momentum in the Construction of Electromagnetic Multipolar Fields

    ERIC Educational Resources Information Center

    Tischler, Nora; Zambrana-Puyalto, Xavier; Molina-Terriza, Gabriel

    2012-01-01

    Multipolar solutions of Maxwell's equations are used in many practical applications and are essential for the understanding of light-matter interactions at the fundamental level. Unlike the set of plane wave solutions of electromagnetic fields, the multipolar solutions do not share a standard derivation or notation. As a result, expressions…

  12. Electrical Engineers' Perceptions on Education--Electromagnetic Field Theory and Its Connection to Working Life

    ERIC Educational Resources Information Center

    Keltikangas, K.; Wallen, H.

    2010-01-01

    This paper investigates electrical engineers' perceptions on their education in Finland, with particular emphasis on the basic electromagnetic field theory courses and their applicability in working life, using two online surveys (n = 99 and n = 120). The answers show a reasonably good satisfaction with the electrical engineering studies in…

  13. Apparent Paradoxes in Classical Electrodynamics: A Fluid Medium in an Electromagnetic Field

    ERIC Educational Resources Information Center

    Kholmetskii, A. L.; Yarman, T.

    2008-01-01

    In this paper we analyse a number of teaching paradoxes of classical electrodynamics, dealing with the relativistic transformation of energy and momentum for a fluid medium in an external electromagnetic field. In particular, we consider a moving parallel plate charged capacitor, where the electric attraction of its plates is balanced by the…

  14. [Effect of electromagnetic field of extremely low frequency on ATPase activity of actomyosin].

    PubMed

    Tseĭslier, Iu V; Sheliuk, O V; Martyniuk, V S; Nuryshchenko, N Ie

    2012-01-01

    The Mg2+/Ca2+ and K(+)-ATPase actomyosin activity of rabbit skeletal muscle was evaluated by the Fiske-Subbarow method during a five-hour exposition of protein solutions in electromagnetic field of extremely low frequency of 8 Hz and 25 microT induction. The results of the study of the ATPase activity of actomyosin upon electromagnetic exposure have shown statistically significant changes that are characterized by a rather complex time dynamics. After 1, 2 and 4 hours of exposure of protein solutions the effect of ELF EMF exposure inhibits the ATPase activity compared to control samples, which are not exposed to the magnetic field. By the third and fifth hours of exposure to the electromagnetic field, there is a significant increase in the ATPase activity of actomyosin. It should be noted that a similar pattern of change in enzyme activity was universal, both for the environment by Mg2+ and Ca2+, and in the absence of these ions in the buffer. This can evidence for Ca(2+)-independent ways of the infuence of electromagnetic field (EMP) on biologic objects. In our opinion, the above effects are explained by EMP influence on the dynamic properties of actomyosin solutions, which are based on the processes of spontaneous dynamic formation of structure.

  15. [Development of innovative methods of electromagnetic field evaluation for portable radio-station].

    PubMed

    Rubtsova, N B; Perov, S Iu; Bogacheva, E V; Kuster, N

    2013-01-01

    The results of portable radio-station "Radiy-301" electromagnetic fields (EMF) emission measurement and specific absorption rate data evaluation has shown that workers' exposure EMF levels may elevate hygienic norms and hereupon can be health risk factor. Possible way of portable radio-station EMF dosimetry enhancement by means of domestic and international approaches harmonization is considered.

  16. Meta-gated channel for the discrete control of electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Yang, Rui; Wang, Hui; Shi, Ayuan; Zhang, Aofang; Wang, Jing; Gao, Dongxing; Lei, Zhenya; Hu, Bowei

    2016-08-01

    We demonstrate the meta-gate controlled wave propagation through multiple metallic plates with properly devised sub-wavelength defect apertures. Different from using gradient refractive-index meta-materials or phase-discontinuity meta-surfaces to produce the discrepancy between the incident angle and the refractive angle, our technique redirects electromagnetic fields by setting-up discrete transmission gateways between adjacent meta-gates and creates the perfect channels for the wave propagation. Electromagnetic fields can be assigned in the response of the driving frequency of meta-gates with extraordinary transmissions and propagate simply relying on their pre-set locations as illustrated by the meta-gate guided electromagnetic fields travelling in the paths of the Silk-Road and the contour line of Xi'an city where the Silk-Road starts. The meta-gate concept, offering the feasibility of the discrete control of electromagnetic fields with gating routes, may pave an alternative way for precisely transmitting of signals and efficiently sharing of resource in the communication.

  17. Extremely low-frequency electromagnetic fields cause DNA strand breaks in normal cells

    PubMed Central

    2014-01-01

    Background Extremely low frequency electromagnetic fields aren’t considered as a real carcinogenic agent despite the fact that some studies have showed impairment of the DNA integrity in different cells lines. The aim of this study was evaluation of the late effects of a 100 Hz and 5.6 mT electromagnetic field, applied continuously or discontinuously, on the DNA integrity of Vero cells assessed by alkaline Comet assay and by cell cycle analysis. Normal Vero cells were exposed to extremely low frequency electromagnetic fields (100 Hz, 5.6 mT) for 45 minutes. The Comet assay and cell cycle analysis were performed 48 hours after the treatment. Results Exposed samples presented an increase of the number of cells with high damaged DNA as compared with non-exposed cells. Quantitative evaluation of the comet assay showed a significantly (<0.001) increase of the tail lengths, of the quantity of DNA in tail and of Olive tail moments, respectively. Cell cycle analysis showed an increase of the frequency of the cells in S phase, proving the occurrence of single strand breaks. The most probable mechanism of induction of the registered effects is the production of different types of reactive oxygen species. Conclusions The analysis of the registered comet indices and of cell cycle showed that extremely low frequency electromagnetic field of 100 Hz and 5.6 mT had a genotoxic impact on Vero cells. PMID:24401758

  18. Nondiagonal Values of the Heat Kernel for Scalars in a Constant Electromagnetic Field

    NASA Astrophysics Data System (ADS)

    Kalinichenko, I. S.; Kazinski, P. O.

    2017-03-01

    An original method for finding the nondiagonal values of the heat kernel associated with the wave operator Fourier-transformed in time is proposed for the case of a constant external electromagnetic field. The connection of the trace of such a heat kernel to the one-loop correction to the grand thermodynamic potential is indicated. The structure of its singularities is analyzed.

  19. Jet engine with electromagnetic field excitation of expendable solid-state material

    NASA Astrophysics Data System (ADS)

    Tsybin, O. Yu.; Makarov, S. B.; Ostapenko, O. N.

    2016-12-01

    Electromagnetic field action on a solid-state natural raw material is considered here in the context of producing a mechanical reactive momentum. We suggest the development of a jet engine that possesses fast control and low thrust based on desorption or sputtering of particles flow from a solid surface.

  20. Electromagnetic field distributions in waveguide-based axial-type microwave plasma source

    NASA Astrophysics Data System (ADS)

    Nowakowska, H.; Jasiński, M.; Mizeraczyk, J.

    2009-08-01

    We present results from simulations of 2D distributions of the electromagnetic field inside a waveguide-based axial-type microwave plasma source (MPS) used for hydrogen production via methane reforming. The studies are aimed at optimization of discharge processes and hydrogen production. We derive equations for determining electromagnetic field distributions and next determine the electromagnetic field distributions for two cases - without and with plasma inside the MPS. For the first case, we examine the influence of the length of the inner conductor of the coaxial line on electromagnetic field distributions. We have obtained standing wave patterns along the coaxial line and found resonances for certain positions of the coaxial line inner conductor. For the case with plasma inside the MPS, we perform calculations assuming that distributions of plasma parameters are known. Simulations are done for several values of maximum electron density. We have found that for values of electron density greater than 3× 10^{18} m^{-3} strong skin effect in the plasma is observed. Consequently, plasma may be treated as an extension of the inner conductor of the coaxial line. We have used FlexPDE software for the calculations.

  1. Possible Mechanism of Action of the Electromagnetic Fields of Ultralow Frequency on G-protein

    SciTech Connect

    Nava, J. J. Godina; Segura, M. A. Rodriguez; Garcia, M. N. Jimenez; Cadena, M. S. Reyes

    2008-08-11

    Based in several clinical achievements and mathematical simulation of the immune sytem, previously studied, permit us to establish that a possible Mechanism of Action of ultralow frequency Electromagnetic Fields (ELF) is on G-protein as it has been proposed in specialized literature.

  2. Biological Effects of Weak Electromagnetic Field on Healthy and Infected Lime (Citrus aurantifolia) Trees with Phytoplasma

    PubMed Central

    Abdollahi, Fatemeh; Niknam, Vahid; Ghanati, Faezeh; Masroor, Faribors; Noorbakhsh, Seyyed Nasr

    2012-01-01

    Exposure to electromagnetic fields (EMF) has become an issue of concern for a great many people and is an active area of research. Phytoplasmas, also known as mycoplasma-like organisms, are wall-less prokaryotes that are pathogens of many plant species throughout the world. Effects of electromagnetic fields on the changes of lipid peroxidation, content of H2O2, proline, protein, and carbohydrates were investigated in leaves of two-year-old trees of lime (Citrus aurantifolia) infected by the Candidatus Phytoplasma aurantifoliae. The healthy and infected plants were discontinuously exposed to a 10 KHz quadratic EMF with maximum power of 9 W for 5 days, each 5 h, at 25°C. Fresh and dry weight of leaves, content of MDA, proline, and protein increased in both healthy and infected plants under electromagnetic fields, compared with those of the control plants. Electromagnetic fields decreased hydrogen peroxide and carbohydrates content in both healthy and infected plants compared to those of the controls. PMID:22649313

  3. Terahertz Solitons in Biomolecular Systems and their Excitation by External Electromagnetic Field

    NASA Astrophysics Data System (ADS)

    Bugay, A. N.

    2015-09-01

    Nonlinear dynamics of charge and acoustic excitations in cellular microtubules is considered. Different types of nonlinear solitary waves were studied taking account for dissipation. The mechanism of electro-acoustic pulse excitation by external electromagnetic field of terahertz frequency is recognized.

  4. Fields and permeances of flat rectangular and cylindrical DC electromagnetic structures

    SciTech Connect

    Zayirnyak, M.V.; Nasar, S.A.

    1985-03-01

    Analytical solutions to the field problem of flat rectangular and axially symmetric cylindrical dc electromagnetic systems are presented. It is shown that the flat configuration is a special case of the general solution. The results are presented in normalized forms as permeance functions. Calculated results are compared with those obtained experimentally.

  5. A wave guide model of lightning currents and their electromagnetic field

    NASA Technical Reports Server (NTRS)

    Volland, H.

    1980-01-01

    Lightning channels are considered as resonant wave guides in which only standing resonant wave modes can be excited. Two types of discharging currents develop. Type 1 is an aperiodic wave; type 2 is a damped oscillation. The electromagnetic radiation field of both types of currents is calculated and compared with the observation.

  6. Experimental evidence of a potentially increased thrombo-embolic disease risk by domestic electromagnetic field exposure.

    PubMed

    Caprani, A; Richert, A; Flaud, P

    2004-05-01

    We have used the EaHy926 endothelial cell line, able to secrete both pro and anti-aggregant platelet agents, as a model for thrombo-embolic diseases. We experimentally established, by comparing these two secretions with or without a Faraday cage, that the environmental electromagnetic field significantly increases the thrombo-embolic risks in this endothelial cell line.

  7. ALTERATIONS IN CALCIUM ION ACTIVITY BY ELF AND RF ELECTROMAGNETIC FIELDS

    EPA Science Inventory



    Alterations in calcium ion activity by ELF and RF electromagnetic fields

    Introduction

    Calcium ions play many important roles in biological systems. For example, calcium ion activity can be used as an indicator of second-messenger signal-transduction processe...

  8. Controlling electromagnetic fields at boundaries of arbitrary geometries

    NASA Astrophysics Data System (ADS)

    Teo, Jonathon Yi Han; Wong, Liang Jie; Molardi, Carlo; Genevet, Patrice

    2016-08-01

    Rapid developments in the emerging field of stretchable and conformable photonics necessitate analytical expressions for boundary conditions at metasurfaces of arbitrary geometries. Here, we introduce the concept of conformal boundary optics: a design theory that determines the optical response for designer input and output fields at such interfaces. Given any object, we can realize coatings to achieve exotic effects like optical illusions and anomalous diffraction behavior. This approach is relevant to a broad range of applications from conventional refractive optics to the design of the next-generation of wearable optical components. This concept can be generalized to other fields of research where designer interfaces with nontrivial geometries are encountered.

  9. Exact Classical and Quantum Dynamics in Background Electromagnetic Fields

    NASA Astrophysics Data System (ADS)

    Heinzl, Tom; Ilderton, Anton

    2017-03-01

    Analytic results for (Q)ED processes in external fields are limited to a few special cases, such as plane waves. However, the strong focusing of intense laser fields implies a need to go beyond the plane wave model. By exploiting Poincaré symmetry and superintegrability we show how to construct, and solve without approximation, new models of laser-matter interactions. We illustrate the method with a model of a radially polarized (TM) laser beam, for which we exactly determine the classical orbits and quantum wave functions. Including in this way the effects of transverse field structure should improve predictions and analyses for experiments at intense laser facilities.

  10. Rotating-Electric-Field-Induced Carbon-Nanotube-Based Nanomotor in Water: A Molecular Dynamics Study.

    PubMed

    Rahman, Md Mushfiqur; Chowdhury, Mokter Mahmud; Alam, Md Kawsar

    2017-03-29

    Using molecular dynamics simulations, it is shown that a carbon nanotube (CNT) suspended in water and subjected to a rotating electric field of proper magnitude and angular speed can be rotated with the aid of water dipole orientations. Based on this principle, a rotational nanomotor structure is designed and the system is simulated in water. Use of the fast responsiveness of electric-field-induced CNT orientation in water is employed and its operation at ultrahigh-speed (over 10(11) r.p.m.) is shown. To explain the basic mechanism, the behavior of the rotational actuation, originated from the water dipole orientation, is also analyzed . The proposed nanomotor is capable of rotating an attached load (such as CNT) at a precise angle as well as nanogear-based complex structures. The findings suggest potential way of using the electric-field-induced CNT rotation in a polarizable fluids as a novel tool to operate nanodevices and systems.

  11. Fifty hertz extremely low-frequency electromagnetic field causes changes in redox and differentiative status in neuroblastoma cells.

    PubMed

    Falone, Stefano; Grossi, Maria R; Cinque, Benedetta; D'Angelo, Barbara; Tettamanti, Enzo; Cimini, Annamaria; Di Ilio, Carmine; Amicarelli, Fernanda

    2007-01-01

    The current study was designed to establish whether extremely low-frequency electromagnetic fields might affect neuronal homeostasis through redox-sensitive mechanisms. To this end, intracellular reactive oxygen species production, antioxidant and glutathione-based detoxifying capability and genomic integrity after extremely low-frequency electromagnetic fields exposure were investigated. Moreover, we also studied potential extremely low-frequency electromagnetic fields-dependent changes in the proliferative and differentiative cellular status. Results seem to support redox-mediated extremely low-frequency electromagnetic fields effects on biological models as, although no major oxidative damage was detected, after exposure we observed a positive modulation of antioxidant enzymatic expression, as well as a significant increase in reduced glutathione level, indicating a shift of cellular environment towards a more reduced state. In addition, extremely low-frequency electromagnetic fields treatment induced a more differentiated phenotype as well as an increased expression in peroxisome proliferators-activated receptor isotype beta, a class of transcription factors related to neuronal differentiation and cellular stress response. As second point, to deepen how extremely low-frequency electromagnetic fields treatment could affect neuroblastoma cell antioxidant capacity, we examined the extremely low-frequency electromagnetic fields-dependent modifications of cell susceptibility to pro-oxidants. Results clearly showed that 50 Hz extremely low-frequency electromagnetic fields exposure reduces cell tolerance towards oxidative attacks.

  12. Rayleigh-Taylor-Induced Electromagnetic Fields in Laser-Produced Plasmas

    NASA Astrophysics Data System (ADS)

    Manuel, Mario J.-E.

    Spontaneous electromagnetic fields can be important to the dynamic evolution of a plasma by directing heat flow as well as providing additional pressures on the conducting fluids through the Lorentz force. Electromagnetic fields are predicted to affect fluid behavior during the core-collapse of supernovae through generation of fields due to hydrodynamic instabilities. In the coronae of stars, self-generated magnetic fields lead to filamentary structure in the hot plasma. Recent experiments by Gregori et al. investigated sources of protogalactic magnetic fields generated by laser-produced shock waves. In inertial confinement fusion experiments, self-generated electromagnetic fields can also play a role and have recently become of great interest to the community. Present day laser facilities provide a unique opportunity to study spontaneous field-generation in these extreme environments under controlled conditions. Instability-induced electromagnetic fields were investigated using a novel monoenergetic-proton radiography system. Fusion protons generated by an 'exploding-pusher' implosion were used to probe laser-irradiated plastic foils with various preimposed surface perturbations. Imaging protons are sensitive to electromagnetic fields and density modulations in the plasma through the Lorentz force and Coulomb collisions, respectively. Corresponding x-ray radiographs of these targets provided mass density distributions and Coulomb effects on protons were assessed using a Monte Carlo code written using the Geant4 framework. Proton fluence distributions were recorded on CR-39 detectors and Fourier analyzed to infer path-integrated field strengths. Rayleigh-Taylor (RT) growth of preimposed surface perturbations generated magnetic fields by the RT-induced Biermann battery and were measured for the first time. Good data were obtained during linear growth and when compared to ideal calculations, demonstrated that field diffusion near the source played an important role

  13. Non-Uniform Electromagnetic Fields in the SAMURAI TPC

    NASA Astrophysics Data System (ADS)

    Estee, J.; Barney, J.; Chajecki, Z.; Chan, C. F.; Dunn, J. W.; Gilbert, J.; Lu, F.; Lynch, W. G.; Shane, R.; Tsang, M. B.; McIntosh, A. B.; Yennello, S. J.; Famiano, M.; Isobe, T.; Sakurai, H.; Taketani, A.; Murakami, T.; Samurai-Tpc Collaboration

    2011-10-01

    A Time Projection Chamber (TPC) is being developed for the SAMURAI dipole magnet at RIKEN. The main scientific objective for the TPC is to provide constraints on the nuclear symmetry at supra-saturation density. The poster presentation will discuss the design of the TPC field cage and the external electrodes that shape the high electric fields near the cathode. Garfield calculations of the electric field as well as TOSCA calculations of the magnetic field of the SAMURAI dipole will be shown and the impact of the non-uniformity of both fields on electron transport will be discussed. These non-uniformities can introduce components into the electron drift velocity in directions other than the expected vertical direction. This poster presentation will discuss the initial design of a laser calibration system, which will be used to calibrate away the influence of these non-uniformities in the electric and magnetic fields. This work is supported by the DOE under Grant DE-SC0004835.

  14. Electromagnetic field interactions with the human body: Observed effects and theories

    NASA Technical Reports Server (NTRS)

    Raines, J. K.

    1981-01-01

    The effects of nonionizing electromagnetic (EM) field interactions with the human body were reported and human related studies were collected. Nonionizing EM fields are linked to cancer in humans in three different ways: cause, means of detection, and effective treatment. Bad and benign effects are expected from nonionizing EM fields and much more knowledge is necessary to properly categorize and qualify EM field characteristics. It is concluded that knowledge of the boundary between categories, largely dependent on field intensity, is vital to proper future use of EM radiation for any purpose and the protection of the individual from hazard.

  15. Dynamical equations and transport coefficients for the metals at high pulse electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Volkov, N. B.; Chingina, E. A.; Yalovets, A. P.

    2016-11-01

    We offer a metal model suitable for the description of fast electrophysical processes in conductors under influence of powerful electronic and laser radiation of femto- and picosecond duration, and also high-voltage electromagnetic pulses with picosecond front and duration less than 1 ns. The obtained dynamic equations for metal in approximation of one quasineutral liquid are in agreement with the equations received by other authors formerly. New wide-range expressions for the electronic conduction in strong electromagnetic fields are obtained and analyzed.

  16. Radiation reaction from electromagnetic fields in the neighborhood of a point charge

    NASA Astrophysics Data System (ADS)

    Singal, Ashok K.

    2017-03-01

    From the expression for the electromagnetic field in the neighborhood of a point charge, we determine the rate of electromagnetic momentum flow, calculated using the Maxwell stress tensor, across a surface surrounding the charge. From that we derive for a "point" charge the radiation reaction formula, which turns out to be proportional to the first time-derivative of the acceleration of the charge, identical to the expression for the self-force, hitherto obtained in the literature from the detailed mutual interaction between constituents of a small charged sphere. We then use relativistic transformations to arrive at a generalized formula for radiation reaction for a point charge undergoing relativistic motion.

  17. Effects of low-intensity pulsed electromagnetic fields on the early development of sea urchins

    SciTech Connect

    Falugi, C.; Grattarola, M.; Prestipino, G.

    1987-06-01

    The effects of weak electromagnetic signals on the early development of the sea urchin Paracentrotus lividus have been studied. The duration and repetition of the pulses were similar to those used for bone healing in clinical practice. A sequence of pulses, applied for a time ranging from 2 to 4 h, accelerates the cleavages of sea urchin embryo cells. This effect can be quantitatively assessed by determining the time shifts induced by the applied electromagnetic field on the completion of the first and second cleavages in a population of fertilized eggs. The exposed embryos were allowed to develop up to the pluteus stage, showing no abnormalities.

  18. Investigation of Electromagnetic Field Threat to Fuel Tank Wiring of a Transport Aircraft

    NASA Technical Reports Server (NTRS)

    Ely, Jay J.; Nguyen, Truong X.; Dudley, Kenneth L.; Scearce, Stephen A.; Beck, Fred B.; Deshpande, Manohar D.; Cockrell, C. R.

    2000-01-01

    National Transportation Safety Board investigators have questioned whether an electrical discharge in the Fuel Quantity Indication System (FQIS) may have initiated the TWA-800 center wing tank explosion. Because the FQIS was designed to be incapable of producing such a discharge on its own, attention has been directed to mechanisms of outside electromagnetic influence. To support the investigation, the NASA Langley Research Center was tasked to study the potential for radiated electromagnetic fields from external radio frequency (RF) transmitters and passenger carried portable electronic devices (PEDs) to excite the FQIS enough to cause arcing, sparking or excessive heating within the fuel tank.

  19. The Vacuum Electromagnetic Fields and the Schrödinger Equation

    NASA Astrophysics Data System (ADS)

    Faria, A. J.; França, H. M.; Gomes, G. G.; Sponchiado, R. C.

    2007-08-01

    We consider the simple case of a nonrelativistic charged harmonic oscillator in one dimension, to investigate how to take into account the radiation reaction and vacuum fluctuation forces within the Schrödinger equation. The effects of both zero-point and thermal classical electromagnetic vacuum fields, characteristic of stochastic electrodynamics, are separately considered. Our study confirms that the zero-point electromagnetic fluctuations are dynamically related to the momentum operator p=- i ℏ ∂/ ∂ x used in the Schrödinger equation.

  20. Electromagnetic field effects on cells of the immune system: The role of calcium signaling

    SciTech Connect

    Walleczek, J. )

    1992-10-01

    During the past decade considerable evidence has accumulated demonstrating that nonthermal exposures of cells of the immune system to extremely low-frequency (ELF) electromagnetic fields (< 300 Hz) can elicit cellular changes that might be relevant to in vivo immune activity. A similar responsiveness to nonionizing electromagnetic energy in this frequency range has also been documented for tissues of the neuroendocrine and musculoskeletal system. However, knowledge about the underlying biological mechanisms by which such fields can induce cellular changes is still very limited. It is generally believed that the cell membrane and Ca[sup 2+]-regulated activity is involved in bioactive ELF field coupling to living systems. This article begins with a short review of the current state of knowledge concerning the effects of nonthermal levels of ELF electromagnetic fields on the biochemistry and activity of immune cells and then closely examines new results that suggest a role for Ca[sup 2+] in the induction of these cellular field effects. Based on these findings it is proposed that membrane-mediated Ca[sup 2+] in the induction of these cellular field effects. Based on these findings it is proposed that membrane-mediated Ca[sup 2+] signaling processes are involved in the mediation of field effects on the immune system. 69 refs., 2 tabs.

  1. The cavity electromagnetic field within the polarizable continuum model of solvation

    NASA Astrophysics Data System (ADS)

    Pipolo, Silvio; Corni, Stefano; Cammi, Roberto

    2014-04-01

    Cavity field effects can be defined as the consequences of the solvent polarization induced by the probing electromagnetic field upon spectroscopies of molecules in solution, and enter in the definitions of solute response properties. The polarizable continuum model of solvation (PCM) has been extended in the past years to address the cavity-field issue through the definition of an effective dipole moment that couples to the external electromagnetic field. We present here a rigorous derivation of such cavity-field treatment within the PCM starting from the general radiation-matter Hamiltonian within inhomogeneous dielectrics and recasting the interaction term to a dipolar form within the long wavelength approximation. To this aim we generalize the Göppert-Mayer and Power-Zienau-Woolley gauge transformations, usually applied in vacuo, to the case of a cavity vector potential. Our derivation also allows extending the cavity-field correction in the long-wavelength limit to the velocity gauge through the definition of an effective linear momentum operator. Furthermore, this work sets the basis for the general PCM treatment of the electromagnetic cavity field, capable to describe the radiation-matter interaction in dielectric media beyond the long-wavelength limit, providing also a tool to investigate spectroscopic properties of more complex systems such as molecules close to large nanoparticles.

  2. Studies on weak electromagnetic fields effects in chick embryos. Annual report, June 1985-June 1986

    SciTech Connect

    Not Available

    1986-05-31

    This research was directed to test some experimental conditions of the Henhouse project and to enforce a previous study on VLF electromagnetic fields effects on chick embryos. Henhouse Project: the response of White Leghorn Hisex embryos to field exposures effective on the Shaver breed, was studied. 1) A 48-hour exposure, in vivo, to a pulsed horizontal field of 100-Hz frequency, 1.0 micro T intensity, 500-microsecond pulse duration and 2-microsecond rise time induced a significant increase of developmental abnormalities in Hisex embryos. 2) A five-hour exposure of stage 7 Hisex embryos changed the Mitotic Index of their neural tissue. So, the early development of Hisex embryos, like Shaver embryos, can be modified by VLF pulsed electromagnetic fields. In the protocol of the Henhouse project, it was suggested a temperature of 38 C for eggs incubation. Studying the development of chick embryos in relation to the temperature, in the range of 37.4-40 C, it was confirmed that a 48-hour incubation at 38 C (with 55% humidity) does not induce abnormalities and allows a convenient developmental growth rate of the chick embryos. Electromagnetic fields effects in relation to the embryos orientation: preliminary results on the induction of abnormalities in field exposed embryos in relation to their orientation were confirmed. In a East-West oriented horizontal pulsed field, the organisms oriented to Southwest and Southeast showed a significant increase of developmental abnormalities. No effect was appreciable among the embryos Southward oriented.

  3. Realization of quantum gates based on three-dimensional harmonic oscillator in a time-varying electromagnetic field

    NASA Astrophysics Data System (ADS)

    Gautam, Kumar; Chauhan, Garv; Rawat, Tarun Kumar; Parthasarathy, Harish; Sharma, Navneet

    2015-09-01

    This paper presents the design of a given quantum unitary gate by perturbing a three-dimensional (3-D) quantum harmonic oscillator with a time-varying but spatially constant electromagnetic field. The idea is based on expressing the radiation- perturbed Hamiltonian as the sum of the unperturbed Hamiltonian and O( e) and perturbations and then solving the Schrödinger equation to obtain the evolution operator at time T up to , and this is a linear-quadratic function of the perturbing electromagnetic field values over the time interval [0, T]. Setting the variational derivative of the error energy with respect to the electromagnetic field values with an average electromagnetic field energy constraint leads to the optimal electromagnetic field solution, a linear integral equation. The reliability of such a gate design procedure in the presence of heat bath coupling is analysed, and finally, an example illustrating how atoms and molecules can be approximated using oscillators is presented.

  4. Structure characteristics in industrially centrifugally cast 25Cr20Ni stainless steel tubes solidified under different electromagnetic field intensity

    SciTech Connect

    Wu, X.Q.; Yang, Y.S.; Zhang, J.S.; Jia, G.L.; Hu, Z.Q.

    1999-10-01

    The influences of different electromagnetic field intensities on the solidification structures of industrially centrifugally cast 25Cr20Ni stainless steel tubes have been investigated in detail. The results reveal that the electromagnetic field exerted during the centrifugal solidification causes a marked variation in the structures of the cast tubes. With an increase of the electromagnetic field intensity, the area fraction of the equiaxed structures in transverse sections of the cast tubes increases, and the macrostructures are gradually refined. The distribution of the eutectic carbides changes from the dendrite boundaries to the grain boundaries. However, an excessive electromagnetic field intensity gives rise to many intergranular cast defects formed along the inner walls of the centrifugally cast tubes. The effects of fluid flow induced by the electromagnetic field on the solidification process of the centrifugally cast tubes are the primary reason for the previously mentioned structure variations.

  5. AC electric field induced dipole-based on-chip 3D cell rotation.

    PubMed

    Benhal, Prateek; Chase, J Geoffrey; Gaynor, Paul; Oback, Björn; Wang, Wenhui

    2014-08-07

    The precise rotation of suspended cells is one of the many fundamental manipulations used in a wide range of biotechnological applications such as cell injection and enucleation in nuclear transfer (NT) cloning. Noticeably scarce among the existing rotation techniques is the three-dimensional (3D) rotation of cells on a single chip. Here we present an alternating current (ac) induced electric field-based biochip platform, which has an open-top sub-mm square chamber enclosed by four sidewall electrodes and two bottom electrodes, to achieve rotation about the two axes, thus 3D cell rotation. By applying an ac potential to the four sidewall electrodes, an in-plane (yaw) rotating electric field is generated and in-plane rotation is achieved. Similarly, by applying an ac potential to two opposite sidewall electrodes and the two bottom electrodes, an out-of-plane (pitch) rotating electric field is generated and rolling rotation is achieved. As a prompt proof-of-concept, bottom electrodes were constructed with transparent indium tin oxide (ITO) using the standard lift-off process and the sidewall electrodes were constructed using a low-cost micro-milling process and then assembled to form the chip. Through experiments, we demonstrate rotation of bovine oocytes of ~120 μm diameter about two axes, with the capability of controlling the rotation direction and the rate for each axis through control of the ac potential amplitude, frequency, and phase shift, and cell medium conductivity. The maximum observed rotation rate reached nearly 140° s⁻¹, while a consistent rotation rate reached up to 40° s⁻¹. Rotation rate spectra for zona pellucida-intact and zona pellucida-free oocytes were further compared and found to have no effective difference. This simple, transparent, cheap-to-manufacture, and open-top platform allows additional functional modules to be integrated to become a more powerful cell manipulation system.

  6. Gene transcription and electromagnetic fields. Final progress report

    SciTech Connect

    Henderson, A.S.

    1992-12-31

    Our overall aim is to obtain sufficient information to allow us to ultimately determine whether ELF EM field exposure is an initiating factor in neoplastic transformation and/or if exposure can mimic characteristics of the second-step counterpart in neoplastic disease. This aim is based on our previous findings that levels of some transcripts are increased in cells exposed to EM fields. While the research is basic in nature, the ramifications have bearing on the general safety of exposure to EM fields in industrial and everyday life. A large array of diverse biological effects are reported to occur as the result of exposure to elf EM fields, suggesting that the cell response to EM fields is at a basic level, presumably initiated by molecular and/or biophysical events at the cell membrane. The hypothesized route is a signal transduction pathway involving membrane calcium fluxes. Information flow resulting from signal transduction can mediate the induction of regulatory factors in the cell, and directly affect how transcription is regulated.

  7. Representative electromagnetic field intensities near the Clam Lake, Wisconsin and Republic, Michigan ELF (Extremely Low Frequency) facilities

    NASA Astrophysics Data System (ADS)

    1984-01-01

    Extremely low frequency electromagnetic fields produced by ELF antennas and commercial power lines at Clam Lake, WI, and by commercial power lines at Republic, MI, have been measured at residences, businesses and forest recreational areas for the continuing assessment of the Navy's ELF Communications Program. The ELF fields from existing antennas at Clam Lake, and from power lines in both states are low. Introducing ELF antenna fields at Republic, MI in several years will not significantly change the electromagnetic environment there. The existing field intensities are interpreted and compared with independent expert, judgment, professional standards-setting and judicial and administrative law opinions regarding safe exposure of the public to ELF electromagnetic fields.

  8. Beta Decay in the Field of an Electromagnetic Wave and Experiments on Measuring the Neutrino Mass

    SciTech Connect

    Dorofeev, O.F.; Lobanov, A.E.

    2005-06-01

    Investigations of the effect of an electromagnetic wave field on the beta-decay process are used to analyze the tritium-decay experimental data on the neutrino mass. It is shown that the electromagnetic wave can distort the beta spectrum, shifting the end point to the higher energy region. This phenomenon is purely classical and it is associated with the electron acceleration in the radiation field. Since strong magnetic fields exist in setups for precise measurement of the neutrino mass, the indicated field can appear owing to the synchrotron radiation mechanism. The phenomenon under consideration can explain the experimentally observed anomalies in the spectrum of the decay electrons; in particular, the effect of the 'negative square of the neutrino mass'.

  9. Propagation of electromagnetic waves parallel to the magnetic field in the nightside Venus ionosphere

    NASA Astrophysics Data System (ADS)

    Huba, J. D.; Rowland, H. L.

    1993-03-01

    The propagation of electromagnetic waves parallel to the magnetic field in the nightside Venus ionosphere is presented in a theoretical and numerical analysis. The model assumes a source of electromagnetic radiation in the Venus atmosphere, such as that produced by lightning. Specifically addressed is wave propagation in the altitude range z = 130-160 km at the four frequencies detectable by the Pioneer Venus Orbiter Electric Field Detector: 100 Hz, 730 Hz, 5.4 kHz, and 30 kHz. Parameterizations of the wave intensities, peak electron density, and Poynting flux as a function of magnetic field are presented. The waves are found to propagate most easily in conditions of low electron density and high magnetic field. The results of the model are consistent with observational data.

  10. Calcium displacement caused by electromagnetic fields. Final report, 1 November 1982-31 August 1989

    SciTech Connect

    Bond, J.D.; Jordan, C.A.

    1989-08-31

    This research effort was to determine theoretically a physical basis for the interaction of low-intensity externally applied electromagnetic fields with biological tissue. The primary aim of the investigation was to establish a molecular basis for the class of interactions commonly referred to as nonthermal effects of electromagnetic fields with biological systems. In particular, the biological structure of interest was the plasma membrane since it had been either directly or indirectly implicated in numerous experimental studies. It was demonstrated how a membrane undergoing a phase transition could qualitatively account for the release and/or uptake of divalent calcium ions. A characterization of changes in the structure of the membrane/electrolyte interface due to field induced changes in enzymatic activity was demonstrated. The role of critical phenomena was shown analytically to be able to account for the unique sensitivity of biomembranes to weak external field perturbations, and describe alterations in the passive transport of sodium ions in rabbit erythrocytes.

  11. THE ROTATION PROFILE OF SOLAR MAGNETIC FIELDS BETWEEN {+-}60 Degree-Sign LATITUDES

    SciTech Connect

    Shi, X. J.; Xie, J. L.

    2013-08-10

    Through a cross-correlation analysis of the Carrington synoptic maps of solar photospheric magnetic fields from Carrington Rotation Nos. 1625 to 2129 (from 1975 February to 2012 October), the sidereal rotation rates of solar magnetic fields between {+-}60 Degree-Sign latitudes are investigated. It seems that the temporal variation of rotation rates should be related to the solar cycle phase. The rotation profile of magnetic fields is obtained: the sidereal rotation rates decrease from the equator to mid-latitude and reach their minimum values of about 13.16 deg day{sup -1} (13.17 deg day{sup -1}) at 53 Degree-Sign (54 Degree-Sign ) latitude in the northern (southern) hemisphere, then increase toward higher latitudes. This rotation profile is different from the differential rotation law obtained by Snodgrass from a cross-correlation analysis of daily magnetograms, in which the rotation rates show a steep decrease from the equator to the poles. However, it is much closer to the quasi-rigid rotation law derived by Stenflo from an auto-correlation analysis of daily magnetograms. Some possible interpretations are discussed for the resulting rotation profile.

  12. Regulation of PCR efficiency with magnetic nanoparticles in a rotating magnetic field

    NASA Astrophysics Data System (ADS)

    Higashi, Toshiaki; Nagaoka, Yutaka; Minegishi, Hiroaki; Echigo, Akinobu; Usami, Ron; Maekawa, Toru; Hanajiri, Tatsuro

    2011-04-01

    The polymerase chain reaction (PCR) method is widely used for the reproduction and amplification of specific DNA segments in vitro, and a novel PCR method using nanomaterials such as gold nanoparticles has recently been reported. This paper reports on the regulation of PCR efficiency with superparamagnetic nanoparticles in a rotating magnetic field. The level of efficiency was successfully regulated in a rotating magnetic field by the authors, and decreased with increasing frequency of the field. The results obtained show that simply controlling the structure and dynamics of magnetic nanoparticle clusters in a rotating magnetic field can regulate PCR efficiency.

  13. Point-source idealization in classical field theories. II. Mechanical energy losses from electromagnetic radiation reaction

    NASA Astrophysics Data System (ADS)

    Kates, Ronald E.; Rosenblum, Arnold

    1982-05-01

    This paper compares the mechanical energy losses due to electromagnetic radiation reaction on a two-particle, slow-motion system, as calculated from (1) the method of matched asymptotic expansions and (2) the Lorentz-Dirac equation, which assumes point sources. The matching derivation of the preceding paper avoided the assumption of a δ-function source by using Reissner-Nordström matching zones. Despite the differing mathematical assumptions of the two methods, their results are in agreement with each other and with the electromagnetic-field energy losses calculated by the evaluation of flux integrals. Our purpose is eventually to analyze Rosenblum's use of point sources as a possible cause of disagreement between the analogous calculations of gravitational radiation on a slow-motion system of two bodies. We begin with the simpler electromagnetic problem.

  14. Self-reported symptoms associated with exposure to electromagnetic fields: a questionnaire study.

    PubMed

    Küçer, Nermin; Pamukçu, Tuğba

    2014-01-01

    Abstract In the last years, it has been discussed frequently whether there are any harmful effects of electromagnetic fields on human health. Electromagnetic fields are generated by several natural and man-made sources. Part of the electromagnetic spectrum called Radiofrequency is used in communication systems such as mobile (cellular) phone and computer. The aim of our study was to explore different self-reported symptoms that may be associated with exposure to electromagnetic fields. This survey study was conducted, using a questionnaire, on 350 people aged +9 years in Turkey. The chi-square test was used for data analysis. Self-reported symptoms were headache, vertigo/dizziness, fatigue, forgetfulness, sleep disturbance-insomnia, tension-anxiety, joint and bone pain, lacrimation of the eyes, hearing loss and tinnitus. As a result of the survey, the study has shown that users of mobile phone and computer more often complained of headache, joint and bone pain, hearing loss, vertigo/dizziness, tension-anxiety symptoms according to time of daily usage (p < 0.05). In users of mobile phone and computer, women significantly (p < 0.05) complained more often of headache, vertigo/dizziness, fatigue, forgetfulness and tension-anxiety than men.

  15. On Sector Magnets or Transverse Electromagnetic Fields in Cylindrical Coordinates

    SciTech Connect

    Zolkin, Timofey

    2016-03-10

    The Laplace's equations for the scalar and vector potentials describing electric or magnetic fields in cylindrical coordinates with translational invariance along azimuthal coordinate are considered. The series of special functions which, when expanded in power series in radial and vertical coordinates, in lowest order replicate the harmonic homogeneous polynomials of two variables are found. These functions are based on radial harmonics found by Edwin~M.~McMillan in his more-than-40-years "forgotten" article, which will be discussed. In addition to McMillan's harmonics, second family of adjoint radial harmonics is introduced, in order to provide symmetric description between electric and magnetic fields and to describe fields and potentials in terms of same special functions. Formulas to relate any transverse fields specified by the coefficients in the power series expansion in radial or vertical planes in cylindrical coordinates with the set of new functions are provided. This result is no doubt important for potential theory while also critical for theoretical studies, design and proper modeling of sector dipoles, combined function dipoles and any general sector element for accelerator physics. All results are presented in connection with these problems.

  16. The Electromagnetic Dipole Radiation Field through the Hamiltonian Approach

    ERIC Educational Resources Information Center

    Likar, A.; Razpet, N.

    2009-01-01

    The dipole radiation from an oscillating charge is treated using the Hamiltonian approach to electrodynamics where the concept of cavity modes plays a central role. We show that the calculation of the radiation field can be obtained in a closed form within this approach by emphasizing the role of coherence between the cavity modes, which is…

  17. Influence of constant, alternating and cyclotron low-intensity electromagnetic fields on fibroblast proliferative activity in vitro.

    PubMed

    Afinogenov, Gennadi; Afinogenova, Anna; Kalinin, Andrey

    2009-12-16

    Available data allow assuming the presence of stimulation of reparative processes under influence of low-intensity electromagnetic field, commensurable with a magnetic field of the Earth. Research of effects of low-intensity electromagnetic fields on fibroblast proliferative activity in human lungs in cell culture was performed.The influence of a constant electromagnetic field, an alternating electromagnetic field by frequency of 50 Hz and cyclotron electromagnetic field with identical intensity for all kinds of fields - 80 mcTl - on value of cellular mass and a correlation of live and dead cells in culture is investigated in three series of experiments. We used the universal electromagnetic radiator generating all three kinds of fields and supplied by a magnetometer which allows measuring the intensity of accurate within 0.1 mcTl including taking into account the Earth's magnetic field intensity.The peak value for stimulation cellular proliferation in the present experiences was two-hour influence by any of the specified kinds of electromagnetic fields. The irradiation by cyclotron electromagnetic field conducts positive dynamics in growth of live cells (up to 206+/-22%) and decreases the number of dead cells (down to 31+/-6%). Application of cyclotron magnetic fields promoted creation of optimum conditions for proliferation. As a result of researches we observed the reliable 30% increase of nitro-tetrazolium index (in nitro-tetrazolium blue test) after irradiation by cyclotron electromagnetic field in experience that testifies to strengthening of the cell breathing of living cells.In our opinion, it is necessary to pay attention not only to a pure gain of cells, but also to reduction of number dead cells that can be criterion of creation of optimum conditions for their specific development and valuable functioning.

  18. Proteomics of human primary osteoarthritic chondrocytes exposed to extremely low-frequency electromagnetic fields (ELF EMFs) and to therapeutic application of musically modulated electromagnetic fields (TAMMEF).

    PubMed

    Corallo, Claudio; Battisti, Emilio; Albanese, Antonietta; Vannoni, Daniela; Leoncini, Roberto; Landi, Giacomo; Gagliardi, Assunta; Landi, Claudia; Carta, Serafino; Nuti, Ranuccio; Giordano, Nicola

    2014-01-01

    Osteoarthritis (OA) is the most frequent joint disease, characterized by degradation of extracellular matrix and alterations in chondrocyte metabolism. Some authors reported that electromagnetic fields (EMFs) can positively interfere with patients affected by OA, even though the nature of the interaction is still debated. Human primary osteoarthritic chondrocytes isolated from the femoral heads of OA-patients undergoing to total hip replacement, were cultured in vitro and exposed 30 min/day for two weeks to extremely-low-frequency electromagnetic field (ELF) with fixed frequency (100 Hz) and to therapeutic application of musically modulated electromagnetic fields (TAMMEF) with variable frequencies, intensities and waveforms. Sham-exposed (S.E.) cells served as control group. Cell viability was measured at days 2, 7 and 14. After two weeks, cell lysates were processed using a proteomic approach. Chondrocyte exposed to ELF and TAMMEF system demonstrated different viability compared to untreated chondrocytes (S.E.). Proteome analysis of 2D-Electrophoresis and protein identification by mass spectrometry showed different expression of proteins derived from nucleus, cytoplasm and organelles. Function analysis of the identified proteins showed changes in related-proteins metabolism (glyceraldeyde-3-phosphate-dehydrogenase), stress response (Mn-superoxide-dismutase, heat-shock proteins), cytoskeletal regulation (actin), proteinase inhibition (cystatin-B) and inflammation regulatory functions (S100-A10, S100-A11) among the experimental groups (ELF, TAMMEF and S.E.). In conclusion, EMFs do not cause damage to chondrocytes, besides stimulate safely OA-chondrocytes and are responsible of different protein expression among the three groups. Furthermore, protein analysis of OA-chondrocytes treated with ELF and the new TAMMEF systems could be useful to clarify the pathogenetic mechanisms of OA by identifying biomarkers of the disease.

  19. Comparison of the genotoxic effects induced by 50 Hz extremely low-frequency electromagnetic fields and 1800 MHz radiofrequency electromagnetic fields in GC-2 cells.

    PubMed

    Duan, Weixia; Liu, Chuan; Zhang, Lei; He, Mindi; Xu, Shangcheng; Chen, Chunhai; Pi, Huifeng; Gao, Peng; Zhang, Yanwen; Zhong, Min; Yu, Zhengping; Zhou, Zhou

    2015-03-01

    Extremely low-frequency electromagnetic fields (ELF-EMF) and radiofrequency electromagnetic fields (RF-EMF) have been considered to be possibly carcinogenic to humans. However, their genotoxic effects remain controversial. To make experiments controllable and results comparable, we standardized exposure conditions and explored the potential genotoxicity of 50 Hz ELF-EMF and 1800 MHz RF-EMF. A mouse spermatocyte-derived GC-2 cell line was intermittently (5 min on and 10 min off) exposed to 50 Hz ELF-EMF at an intensity of 1, 2 or 3 mT or to RF-EMF in GSM-Talk mode at the specific absorption rates (SAR) of 1, 2 or 4 W/kg. After exposure for 24 h, we found that neither ELF-EMF nor RF-EMF affected cell viability using Cell Counting Kit-8. Through the use of an alkaline comet assay and immunofluorescence against γ-H2AX foci, we found that ELF-EMF exposure resulted in a significant increase of DNA strand breaks at 3 mT, whereas RF-EMF exposure had insufficient energy to induce such effects. Using a formamidopyrimidine DNA glycosylase (FPG)-modified alkaline comet assay, we observed that RF-EMF exposure significantly induced oxidative DNA base damage at a SAR value of 4 W/kg, whereas ELF-EMF exposure did not. Our results suggest that both ELF-EMF and RF-EMF under the same experimental conditions may produce genotoxicity at relative high intensities, but they create different patterns of DNA damage. Therefore, the potential mechanisms underlying the genotoxicity of different frequency electromagnetic fields may be different.

  20. Faraday rotation dispersion microscopy imaging of diamagnetic and chiral liquids with pulsed magnetic field.

    PubMed

    Suwa, Masayori; Nakano, Yusuke; Tsukahara, Satoshi; Watarai, Hitoshi

    2013-05-21

    We have constructed an experimental setup for Faraday rotation dispersion imaging and demonstrated the performance of a novel imaging principle. By using a pulsed magnetic field and a polarized light synchronized to the magnetic field, quantitative Faraday rotation images of diamagnetic organic liquids in glass capillaries were observed. Nonaromatic hydrocarbons, benzene derivatives, and naphthalene derivatives were clearly distinguished by the Faraday rotation images due to the difference in Verdet constants. From the wavelength dispersion of the Faraday rotation images in the visible region, it was found that the resonance wavelength in the UV region, which was estimated based on the Faraday B-term, could be used as characteristic parameters for the imaging of the liquids. Furthermore, simultaneous acquisition of Faraday rotation image and natural optical rotation image was demonstrated for chiral organic liquids.

  1. Neurobehavioral effects of power-frequency electromagnetic fields

    SciTech Connect

    Paneth, N.

    1993-12-01

    Some laboratory experiments have suggested that power-frequency electric and magnetic fields (EMF) may be capable of influencing calcium efflux from cell membranes, pineal function, and circadian rhythms. As yet, however, no consistent, replicable laboratory model has been developed for any of these effects. Most assessments of human volunteers exposed to EMF have been negative, but occasional effects on vigilance or alertness and some modest effects on circadian rhythmicity have been reported. Several carefully performed studies of workers occupationally exposed to high electric-field strengths have failed to find effects on behavior or cognitive functioning. Although the bulk of human research on the effects of EMF on cognitive performance is negative, there has been less assessment of behavior and psychiatric symptomatology. Because some studies, in both humans and animals, have described effects of EMF on circadian rhythms, future research might concentrate profitably on the assessment of EMF in relation to depression and other cyclically mediated psychiatric disorders. 40 refs.

  2. Studies on Weak Electromagnetic Fields Effects in Chick Embryos.

    DTIC Science & Technology

    1986-05-31

    of them for the field exposed eggs , the other for the controls. In the first one called "Experimental incubator", are located cylindric coils or...of fertilized chicken eggs in these experimental conditions. In our previous and present studies of EMFs effects on chick embryos development, the...of 34C for eggs in- F30. DISTISUTIONIAVAILAPUTY 00 "ITRACT 21. ABSTRACT SECURITY CLASSIFICATION UCkSSPION~oumITED 03 SAMES As apt. DOI USERS(U

  3. Imaging Nanoscale Electromagnetic Near-Field Distributions Using Optical Forces

    PubMed Central

    Huang, Fei; Ananth Tamma, Venkata; Mardy, Zahra; Burdett, Jonathan; Kumar Wickramasinghe, H.

    2015-01-01

    We demonstrate the application of Atomic Force Microscopy (AFM) for mapping optical near-fields with nanometer resolution, limited only by the AFM probe geometry. By detecting the optical force between a gold coated AFM probe and its image dipole on a glass substrate, we profile the electric field distributions of tightly focused laser beams with different polarizations. The experimentally recorded focal force maps agree well with theoretical predictions based on a dipole-dipole interaction model. We experimentally estimate the aspect ratio of the apex of gold coated AFM probe using only optical forces. We also show that the optical force between a sharp gold coated AFM probe and a spherical gold nanoparticle of radius 15 nm, is indicative of the electric field distribution between the two interacting particles. Photo Induced Force Microscopy (PIFM) allows for background free, thermal noise limited mechanical imaging of optical phenomenon over wide range of wavelengths from Visible to RF with detection sensitivity limited only by AFM performance. PMID:26073331

  4. Entrainment by a rotating magnetic field of a ferrofluid contained in a sphere.

    PubMed

    Felderhof, B U

    2011-10-01

    Entrainment of a ferrofluid contained in a sphere by a rotating uniform magnetic field is studied on the basis of spin-diffusion theory. The equations for flow velocity and spin velocity, coupled to Maxwell's equations of magnetostatics, are solved analytically to second order in the applied magnetic field. A similar derivation holds in electrohydrodynamics for a polar liquid contained in a sphere and subject to a rotating electrical field.

  5. [Physiotherapy with rotating pulse magnetic field in combined therapy of chronic obstructive pulmonary disease].

    PubMed

    Lobanov, A Iu; Gilinskaia, N Iu; Chereĭskaia, N K

    2005-01-01

    Rationale and technique are proposed and clinical trial has been made of efficacy of chronic obstructive pulmonary disease (COPD) treatment with impacts of rotating impulse magnetic field (RIMF) from the device Polyus-VIEM (two fields, induction 48-72 mTe, reversive rotation, 4-6 s reversion duration, 20-30 Hz, 7-10 min exposure of each field, 7-10 procedures). The addition of RIMF in combined treatment of COPD improves treatment and shortens its duration.

  6. Causal signal transmission by quantum fields. VI: The Lorentz condition and Maxwell's equations for fluctuations of the electromagnetic field

    NASA Astrophysics Data System (ADS)

    Plimak, L. I.; Stenholm, S.

    2013-11-01

    The general structure of electromagnetic interactions in the so-called response representation of quantum electrodynamics (QED) is analysed. A formal solution to the general quantum problem of the electromagnetic field interacting with matter is found. Independently, a formal solution to the corresponding problem in classical stochastic electrodynamics (CSED) is constructed. CSED and QED differ only in the replacement of stochastic averages of c-number fields and currents by time-normal averages of the corresponding Heisenberg operators. All relations of QED connecting quantum field to quantum current lack Planck's constant, and thus coincide with their counterparts in CSED. In Feynman's terms, one encounters complete disentanglement of the potential and current operators in response picture.

  7. Interaction of extremely-low-frequency electromagnetic fields with living systems

    SciTech Connect

    Tenforde, T.S.

    1991-11-01

    The sources and physical properties of extremely-low-frequency (ELF) electromagnetic fields are described in this paper. Biological effects and mechanisms through which ELF fields interact with humans and other organisms are discussed, including several aspects of this subject that are presently under active laboratory investigation. Studies on the potential health effects of ELF fields present in the home and workplace are also summarized, including a critical evaluation of evidence for a possible linkage between exposure to ELF fields and cancer risk. 53 refs.

  8. Electromagnetic induction by finite wavenumber source fields in 2-D lateral heterogeneities - The transverse electric mode

    NASA Technical Reports Server (NTRS)

    Hermance, J. F.

    1984-01-01

    Electromagnetic induction in a laterally homogeneous earth is analyzed in terms of a source field with finite dimensions. Attention is focused on a time-varying two-dimensional current source directed parallel to the strike of a two-dimensional anomalous structure within the earth, i.e., the E-parallel mode. The spatially harmonic source field is expressed as discontinuities in the magnetic (or electric) field of the current in the source. The model is applied to describing the magnetic gradients across megatectonic features, and may be used to predict the magnetic fields encountered by a satellite orbiting above the ionosphere.

  9. Force acting on an atom and a classical oscillator in an electromagnetic field

    SciTech Connect

    Makarov, V. P. Rukhadze, A. A.

    2010-01-15

    The expression for the force exerted by the field on an atom and averaged over the field period is derived in quantum-mechanical perturbation theory, in which a quasi-monochromatic electromagnetic field plays the role of a perturbation. An approximate solution is obtained to the classical (Newton) equation of motion in the same field for a harmonic isotropic oscillator. In both problems, the expressions for the force acting on a particle are completely identical if they are written in terms of the polarizability (of the atom and the oscillator). These results conform with the data obtained in macroscopic electrodynamics for rarefied media.

  10. Solution of the field equations for 2-D electromagnetic direct implicit plasma simulation

    NASA Astrophysics Data System (ADS)

    Hewett, D. W.; Langdon, A. B.

    1985-01-01

    A direct implicit particle-in-cell (PIC) simulation model with full electromagnetic (EM) effects has been implemented in 2-D Cartesian geometry. The model, implemented with the D1 time differencing scheme, was first implemented in a 1-D electrostatic (ES) version to gain some experience with spatial differencing in forms suitable for extension to the full EM field in two dimensions. The implicit EM field solve is considerably different from the implicit ES code. The EM field calculation requires an inductive part as well as the electrostatic and the B field must be self-consistently advanced.

  11. Electromagnetically induced transparency in the four-level system driven by bichromatic microwave field

    NASA Astrophysics Data System (ADS)

    Yang, Lijun; Sun, Ke-jia; Zhang, Su-heng; Feng, Xiao-min

    2014-11-01

    We present a theoretical study on the nonlinear behaviors of the electromagnetically induced transparency resonance subject to two microwave driving fields in a four-level atom system. The probe absorption spectrum is obtained by solving numerically the relevant equations of density matrix. It is shown that there are two pairs of the EIT windows in the probe absorption spectrum. The two pairs of EIT windows have symmetry with respect to the resonance frequency of the probe field, and the separation is equal to the Rabi frequency of the resonant microwave driving field. But in each pair, the splitting of two EIT windows is dominated to the strength of detuning microwave driving field.

  12. Quantum and classical statistics of the electromagnetic zero-point field

    NASA Astrophysics Data System (ADS)

    Ibison, Michael; Haisch, Bernhard

    1996-10-01

    A classical electromagnetic zero-point field (ZPF) analog of the vacuum of quantum field theory has formed the basis for theoretical investigations in the discipline known as random or stochastic electrodynamics (SED). In SED the statistical character of quantum measurements is imitated by the introduction of a stochastic classical background electromagnetic field. Random electromagnetic fluctuations are assumed to provide perturbations which can mimic certain quantum phenomena while retaining a purely classical basis, e.g., the Casimir force, the van der Waals force, the Lamb shift, spontaneous emission, the rms radius of a quantum-mechanical harmonic oscillator, and the radius of the Bohr atom. This classical ZPF is represented as a homogeneous, isotropic ensemble of plane electromagnetic waves whose amplitude is exactly equivalent to an excitation energy of hν/2 of the corresponding quantized harmonic oscillator, this being the state of zero excitation of such an oscillator. There is thus no randomness in the classical electric-field amplitudes: Randomness is introduced entirely in the phases of the waves, which are normally distributed. Averaging over the random phases is assumed to be equivalent to taking the ground-state expectation values of the corresponding quantum operator. We demonstrate that this is not precisely correct by examining the statistics of the classical ZPF in contrast to that of the electromagnetic quantum vacuum. Starting with a general technique for the calculation of classical probability distributions for quantum state operators, we derive the distribution for the individual modes of the electric-field amplitude in the ground state as predicted by quantum field theory. We carry out the same calculation for the classical ZPF analog, and show that the distributions are only in approximate agreement, diverging as the density of k states decreases. We then introduce an alternative classical ZPF with a different stochastic character, and

  13. Bubble shape and electromagnetic field in the nonlinear regime for laser wakefield acceleration

    SciTech Connect

    Li, X. F.; Yu, Q.; Huang, S.; Kong, Q.; Gu, Y. J.; Kawata, S.

    2015-08-15

    The electromagnetic field in the electron “bubble” regime for ultra-intense laser wakefield acceleration was solved using the d'Alembert equations. Ignoring the residual electrons, we assume an ellipsoidal bubble forms under ideal conditions, with bubble velocity equal to the speed of light in vacuum. The general solution for bubble shape and electromagnetic field were obtained. The results were confirmed in 2.5D PIC (particle-in-cell) simulations. Moreover, slopes for the longitudinal electric field of larger than 0.5 were found in these simulations. With spherical bubbles, this slope is always smaller than or equal to 0.5. This behavior validates the ellipsoid assumption.

  14. Using the CAVE virtual-reality environment as an aid to 3-D electromagnetic field computation

    SciTech Connect

    Turner, L.R.; Levine, D.; Huang, M.; Papka, M; Kettunen, L.

    1995-08-01

    One of the major problems in three-dimensional (3-D) field computation is visualizing the resulting 3-D field distributions. A virtual-reality environment, such as the CAVE, (CAVE Automatic Virtual Environment) is helping to overcome this problem, thus making the results of computation more usable for designers and users of magnets and other electromagnetic devices. As a demonstration of the capabilities of the CAVE, the elliptical multipole wiggler (EMW), an insertion device being designed for the Advanced Photon Source (APS) now being commissioned at Argonne National Laboratory (ANL), wa made visible, along with its fields and beam orbits. Other uses of the CAVE in preprocessing and postprocessing computation for electromagnetic applications are also discussed.

  15. Electromagnetic fields radiated from a lightning return stroke - Application of an exact solution to Maxwell's equations

    NASA Technical Reports Server (NTRS)

    Le Vine, D. M.; Meneghini, R.

    1978-01-01

    A solution is presented for the electromagnetic fields radiated by an arbitrarily oriented current filament over a conducting ground plane in the case where the current propagates along the filament at the speed of light, and this solution is interpreted in terms of radiation from lightning return strokes. The solution is exact in the fullest sense; no mathematical approximations are made, and the governing differential equations and boundary conditions are satisfied. The solution has the additional attribute of being specified in closed form in terms of elementary functions. This solution is discussed from the point of view of deducing lightning current wave forms from measurements of the electromagnetic fields and understanding the effects of channel tortuosity on the radiated fields. In addition, it is compared with two approximate solutions, the traditional moment approximation and the Fraunhofer approximation, and a set of criteria describing their applicability are presented and interpreted.

  16. Electromagnetic waves destabilized by runaway electrons in near-critical electric fields

    SciTech Connect

    Komar, A.; Pokol, G. I.; Fueloep, T.

    2013-01-15

    Runaway electron distributions are strongly anisotropic in velocity space. This anisotropy is a source of free energy that may destabilize electromagnetic waves through a resonant interaction between the waves and the energetic electrons. In this work, we investigate the high-frequency electromagnetic waves that are destabilized by runaway electron beams when the electric field is close to the critical field for runaway acceleration. Using a runaway electron distribution appropriate for the near-critical case, we calculate the linear instability growth rate of these waves and conclude that the obliquely propagating whistler waves are most unstable. We show that the frequencies, wave numbers, and propagation angles of the most unstable waves depend strongly on the magnetic field. Taking into account collisional and convective damping of the waves, we determine the number density of runaways that is required to destabilize the waves and show its parametric dependences.

  17. Chromosomal damage in human diploid fibroblasts by intermittent exposure to extremely low-frequency electromagnetic fields.

    PubMed

    Winker, Robert; Ivancsits, Sabine; Pilger, Alexander; Adlkofer, Franz; Rüdiger, H W

    2005-08-01

    Environmental exposure to extremely low-frequency electromagnetic fields (ELF-EMFs) has been implicated in the development of cancer in humans. An important basis for assessing a potential cancer risk due to ELF-EMF exposure is knowledge of biological effects on human cells at the chromosomal level. Therefore, we investigated in the present study the effect of intermittent ELF electromagnetic fields (50 Hz, sinusoidal, 5'field-on/10'field-off, 2-24 h, 1 mT) on the induction of micronuclei (MN) and chromosomal aberrations in cultured human fibroblasts. ELF-EMF radiation resulted in a time-dependent increase of micronuclei, which became significant after 10 h of intermittent exposure at a flux density of 1 mT. After approximately 15 h a constant level of micronuclei of about three times the basal level was reached. In addition, chromosomal aberrations were increased up to 10-fold above basal levels. Our data strongly indicate a clastogenic potential of intermittent low-frequency electromagnetic fields, which may lead to considerable chromosomal damage in dividing cells.

  18. Growth characteristics of mung beans and water convolvuluses exposed to 425-MHz electromagnetic fields.

    PubMed

    Jinapang, Peeraya; Prakob, Panida; Wongwattananard, Pongtorn; Islam, Naz E; Kirawanich, Phumin

    2010-10-01

    Effects of high-frequency, continuous wave (CW) electromagnetic fields on mung beans (Vigna radiata L.) and water convolvuluses (Ipomoea aquatica Forssk.) were studied at different growth stages (pre-sown seed and early seedling). Specifically, the effects of the electromagnetic source's power and duration (defined as power-duration level) on the growth of the two species were studied. Mung beans and water convolvuluses were exposed to electromagnetic fields inside a specially designed chamber for optimum field absorption, and the responses of the seeds to a constant frequency at various power levels and durations of exposure were monitored. The frequency used in the experiments was 425 MHz, the field strengths were 1 mW, 100 mW, and 10 W, and the exposure durations were 1, 2, and 4 h. Results show that germination enhancement is optimum for the mung beans at 100 mW/1 h power-duration level, while for water convolvuluses the optimum germination power-duration level was 1 mW/2 h. When both seed types were exposed at the early sprouting phase with their respective optimum power-duration levels for optimum seed growth, water convolvuluses showed growth enhancement while mung bean sprouts showed no effects. Water content analysis of the seeds suggests thermal effects only at higher field strength.

  19. Gauge-invariant expectation values of the energy of a molecule in an electromagnetic field

    SciTech Connect

    Mandal, Anirban; Hunt, Katharine L. C.

    2016-01-28

    In this paper, we show that the full Hamiltonian for a molecule in an electromagnetic field can be separated into a molecular Hamiltonian and a field Hamiltonian, both with gauge-invariant expectation values. The expectation value of the molecular Hamiltonian gives physically meaningful results for the energy of a molecule in a time-dependent applied field. In contrast, the usual partitioning of the full Hamiltonian into molecular and field terms introduces an arbitrary gauge-dependent potential into the molecular Hamiltonian and leaves a gauge-dependent form of the Hamiltonian for the field. With the usual partitioning of the Hamiltonian, this same problem of gauge dependence arises even in the absence of an applied field, as we show explicitly by considering a gauge transformation from zero applied field and zero external potentials to zero applied field, but non-zero external vector and scalar potentials. We resolve this problem and also remove the gauge dependence from the Hamiltonian for a molecule in a non-zero applied field and from the field Hamiltonian, by repartitioning the full Hamiltonian. It is possible to remove the gauge dependence because the interaction of the molecular charges with the gauge potential cancels identically with a gauge-dependent term in the usual form of the field Hamiltonian. We treat the electromagnetic field classically and treat the molecule quantum mechanically, but nonrelativistically. Our derivation starts from the Lagrangian for a set of charged particles and an electromagnetic field, with the particle coordinates, the vector potential, the scalar potential, and their time derivatives treated as the variables in the Lagrangian. We construct the full Hamiltonian using a Lagrange multiplier method originally suggested by Dirac, partition this Hamiltonian into a molecular term H{sub m} and a field term H{sub f}, and show that both H{sub m} and H{sub f} have gauge-independent expectation values. Any gauge may be chosen for the

  20. Gauge-invariant expectation values of the energy of a molecule in an electromagnetic field.

    PubMed

    Mandal, Anirban; Hunt, Katharine L C

    2016-01-28

    In this paper, we show that the full Hamiltonian for a molecule in an electromagnetic field can be separated into a molecular Hamiltonian and a field Hamiltonian, both with gauge-invariant expectation values. The expectation value of the molecular Hamiltonian gives physically meaningful results for the energy of a molecule in a time-dependent applied field. In contrast, the usual partitioning of the full Hamiltonian into molecular and field terms introduces an arbitrary gauge-dependent potential into the molecular Hamiltonian and leaves a gauge-dependent form of the Hamiltonian for the field. With the usual partitioning of the Hamiltonian, this same problem of gauge dependence arises even in the absence of an applied field, as we show explicitly by considering a gauge transformation from zero applied field and zero external potentials to zero applied field, but non-zero external vector and scalar potentials. We resolve this problem and also remove the gauge dependence from the Hamiltonian for a molecule in a non-zero applied field and from the field Hamiltonian, by repartitioning the full Hamiltonian. It is possible to remove the gauge dependence because the interaction of the molecular charges with the gauge potential cancels identically with a gauge-dependent term in the usual form of the field Hamiltonian. We treat the electromagnetic field classically and treat the molecule quantum mechanically, but nonrelativistically. Our derivation starts from the Lagrangian for a set of charged particles and an electromagnetic field, with the particle coordinates, the vector potential, the scalar potential, and their time derivatives treated as the variables in the Lagrangian. We construct the full Hamiltonian using a Lagrange multiplier method originally suggested by Dirac, partition this Hamiltonian into a molecular term Hm and a field term Hf, and show that both Hm and Hf have gauge-independent expectation values. Any gauge may be chosen for the calculations; but

  1. Gauge-invariant expectation values of the energy of a molecule in an electromagnetic field

    NASA Astrophysics Data System (ADS)

    Mandal, Anirban; Hunt, Katharine L. C.

    2016-01-01

    In this paper, we show that the full Hamiltonian for a molecule in an electromagnetic field can be separated into a molecular Hamiltonian and a field Hamiltonian, both with gauge-invariant expectation values. The expectation value of the molecular Hamiltonian gives physically meaningful results for the energy of a molecule in a time-dependent applied field. In contrast, the usual partitioning of the full Hamiltonian into molecular and field terms introduces an arbitrary gauge-dependent potential into the molecular Hamiltonian and leaves a gauge-dependent form of the Hamiltonian for the field. With the usual partitioning of the Hamiltonian, this same problem of gauge dependence arises even in the absence of an applied field, as we show explicitly by considering a gauge transformation from zero applied field and zero external potentials to zero applied field, but non-zero external vector and scalar potentials. We resolve this problem and also remove the gauge dependence from the Hamiltonian for a molecule in a non-zero applied field and from the field Hamiltonian, by repartitioning the full Hamiltonian. It is possible to remove the gauge dependence because the interaction of the molecular charges with the gauge potential cancels identically with a gauge-dependent term in the usual form of the field Hamiltonian. We treat the electromagnetic field classically and treat the molecule quantum mechanically, but nonrelativistically. Our derivation starts from the Lagrangian for a set of charged particles and an electromagnetic field, with the particle coordinates, the vector potential, the scalar potential, and their time derivatives treated as the variables in the Lagrangian. We construct the full Hamiltonian using a Lagrange multiplier method originally suggested by Dirac, partition this Hamiltonian into a molecular term Hm and a field term Hf, and show that both Hm and Hf have gauge-independent expectation values. Any gauge may be chosen for the calculations; but

  2. Vortex Formation of Rotating Bose-Einstein Condensates in Synthetic Magnetic Field with Optical Lattice

    NASA Astrophysics Data System (ADS)

    Zhao, Qiang

    2016-02-01

    Motivated by recent experiments carried out by Spielman's group at NIST, we study the vortex formation in a rotating Bose-Einstein condensate in synthetic magnetic field confined in a harmonic potential combined with an optical lattice. We obtain numerical solutions of the two-dimensional Gross-Pitaevskii equation and compare the vortex formation by synthetic magnetic field method with those by rotating frame method. We conclude that a large angular momentum indeed can be created in the presence of the optical lattice. However, it is still more difficult to rotate the condensate by the synthetic magnetic field than by the rotating frame even if the optical lattice is added, and the chemical potential and energy remain almost unchanged by increasing rotational frequency.

  3. A hybrid actuated microrobot using an electromagnetic field and flagellated bacteria for tumor-targeting therapy.

    PubMed

    Li, Donghai; Choi, Hyunchul; Cho, Sunghoon; Jeong, Semi; Jin, Zhen; Lee, Cheong; Ko, Seong Young; Park, Jong-Oh; Park, Sukho

    2015-08-01

    In this paper, we propose a new concept for a hybrid actuated microrobot for tumor-targeting therapy. For drug delivery in tumor therapy, various electromagnetic actuated microrobot systems have been studied. In addition, bacteria-based microrobot (so-called bacteriobot), which use tumor targeting and the therapeutic function of the bacteria, has also been proposed for solid tumor therapy. Compared with bacteriobot, electromagnetic actuated microrobot has larger driving force and locomotive controllability due to their position recognition and magnetic field control. However, because electromagnetic actuated microrobot does not have self-tumor targeting, they need to be controlled by an external magnetic field. In contrast, the bacteriobot uses tumor targeting and the bacteria's own motility, and can exhibit self-targeting performance at solid tumors. However, because the propulsion forces of the bacteria are too small, it is very difficult for bacteriobot to track a tumor in a vessel with a large bloodstream. Therefore, we propose a hybrid actuated microrobot combined with electromagnetic actuation in large blood vessels with a macro range and bacterial actuation in small vessels with a micro range. In addition, the proposed microrobot consists of biodegradable and biocompatible microbeads in which the drugs and magnetic particles can be encapsulated; the bacteria can be attached to the surface of the microbeads and propel the microrobot. We carried out macro-manipulation of the hybrid actuated microrobot along a desired path through electromagnetic field control and the micro-manipulation of the hybrid actuated microrobot toward a chemical attractant through the chemotaxis of the bacteria. For the validation of the hybrid actuation of the microrobot, we fabricated a hydrogel microfluidic channel that can generate a chemical gradient. Finally, we evaluated the motility performance of the hybrid actuated microrobot in the hydrogel microfluidic channel. We expect

  4. Enhanced responsiveness to parathyroid hormone and induction of functional differentiation of cultured rabbit costal chondrocytes by a pulsed electromagnetic field.

    PubMed

    Hiraki, Y; Endo, N; Takigawa, M; Asada, A; Takahashi, H; Suzuki, F

    1987-10-22

    Pulsed electromagnetic fields promote healing of delayed united and ununited fractures by triggering a series of events in fibrocartilage. We examined the effects of a pulsed electromagnetic field (recurrent bursts, 15.4 Hz, of shorter pulses of an average of 2 gauss) on rabbit costal chondrocytes in culture. A pulsed electromagnetic field slightly reduced the intracellular cyclic adenosine 3',5'-monophosphate (cAMP) level in the culture. However, it significantly enhanced cAMP accumulation in response to parathyroid hormone (PTH) to 140% of that induced by PTH in its absence, while it did not affect cAMP accumulation in response to prostaglandin E1 or prostaglandin I2. The effect on cAMP accumulation in response to PTH became evident after exposure of the cultures to the pulsed electromagnetic field for 48 h, and was dependent upon the field strength. cAMP accumulation in response to PTH is followed by induction of ornithine decarboxylase, a good marker of differentiated chondrocytes, after PTH treatment for 4 h. Consistent with the enhanced cAMP accumulation, ornithine decarboxylase activity induced by PTH was also increased by the pulsed electromagnetic field to 170% of that in cells not exposed to a pulsed electromagnetic field. Furthermore, stimulation of glycosaminoglycan synthesis, a differentiated phenotype, in response to PTH was significantly enhanced by a pulsed electromagnetic field. Thus, a pulsed electromagnetic field enhanced a series of events in rabbit costal chondrocytes in response to PTH. These findings show that exposure of chondrocytes to a pulsed electromagnetic field resulted in functional differentiation of the cells.

  5. Electromagnetic field redistribution induced selective plasmon driven surface catalysis in metal nanowire-film systems

    NASA Astrophysics Data System (ADS)

    Pan, Liang; Huang, Yingzhou; Yang, Yanna; Xiong, Wen; Chen, Guo; Su, Xun; Wei, Hua; Wang, Shuxia; Wen, Weijia

    2015-11-01

    For the novel interpretation of Raman spectrum from molecule at metal surface, the plasmon driven surface catalysis (PDSC) reactions have become an interesting topic in the research field of surface enhanced Raman scattering (SERS). In this work, the selective PDSC reactions of p,p’-dimercaptoazobenzene (DMAB) produced from para-aminothiophenol (PATP) or 4-nitrobenzenethiol (4NBT) were demonstrated in the Ag nanowires dimer-Au film systems. The different SERS spectra collected at individual part and adjacent part of the same nanowire-film system pointed out the importance of the electromagnetic field redistribution induced by image charge on film in this selective surface catalysis, which was confirmed by the simulated electromagnetic simulated electro- magnetic field distributions. Our result indicated this electromagnetic field redistribution induced selective surface catalysis was largely affected by the polarization and wavelength of incident light but slightly by the difference in diameters between two nanowires. Our work provides a further understanding of PDSC reaction in metal nanostructure and could be a deep support for the researches on surface catalysis and surface analysis.

  6. Calculation of the surface effect in the ferromagnetic conductor with the harmonic electromagnetic field

    NASA Astrophysics Data System (ADS)

    Nosov, G. V.; Kuleshova, E. O.; Vassilyeva, Yu Z.; Elizarov, A. I.

    2016-04-01

    The authors of the paper have obtained formulas for analytical calculation of the constants with the harmonic electromagnetic field, which characterize the surface layer (a skin layer) of the ferromagnetic conductors in case of heating and nonlinear magnetic properties, which can be used for practical calculation of the electromagnetic screens, rotors of the electrical machines and inductive heating installations. A nonlinear dependence of the magnetic induction on the magnetic tension of the ferromagnetic conductor is replaced by one or two linear sections. It is considered that the skin layer of the conductor has constant quantities of the specific conductivity and averaged temperature. Linear electrodynamics equations are solved for the conductive half-space. Parameters of the ferromagnetic conductor's surface layer are calculated: magnetic permeability, the thickness of the skin layer and its averaged temperature, exposure time of the electromagnetic field on the conductor with the established maximum temperature on the conductor's surface, pressure of the field on the conductor and its resistance, inductivity of the internal magnetic field in the conductor, the thermal energy capacity. The methods credibility is confirmed with the concurrence of the resistance and inductiviry of the ferromagnetic conductor with analogous quantities from other methods.

  7. Worldline approach for numerical computation of electromagnetic Casimir energies: Scalar field coupled to magnetodielectric media

    NASA Astrophysics Data System (ADS)

    Mackrory, Jonathan B.; Bhattacharya, Tanmoy; Steck, Daniel A.

    2016-10-01

    We present a worldline method for the calculation of Casimir energies for scalar fields coupled to magnetodielectric media. The scalar model we consider may be applied in arbitrary geometries, and it corresponds exactly to one polarization of the electromagnetic field in planar layered media. Starting from the field theory for electromagnetism, we work with the two decoupled polarizations in planar media and develop worldline path integrals, which represent the two polarizations separately, for computing both Casimir and Casimir-Polder potentials. We then show analytically that the path integrals for the transverse-electric polarization coupled to a dielectric medium converge to the proper solutions in certain special cases, including the Casimir-Polder potential of an atom near a planar interface, and the Casimir energy due to two planar interfaces. We also evaluate the path integrals numerically via Monte Carlo path-averaging for these cases, studying the convergence and performance of the resulting computational techniques. While these scalar methods are only exact in particular geometries, they may serve as an approximation for Casimir energies for the vector electromagnetic field in other geometries.

  8. Accuracy of electromagnetic tracking with a prototype field generator in an interventional OR setting

    SciTech Connect

    Boe, Lars Eirik; Leira, Haakon Olav; Tangen, Geir Arne; Hofstad, Erlend Fagertun; Amundsen, Tore; Langoe, Thomas

    2012-01-15

    Purpose: The authors have studied the accuracy and robustness of a prototype electromagnetic window field generator (WFG) in an interventional radiology suite with a robotic C-arm. The overall purpose is the development of guidance systems combining real-time imaging with tracking of flexible instruments for bronchoscopy, laparoscopic ultrasound, endoluminal surgery, endovascular therapy, and spinal surgery. Methods: The WFG has a torus shape, which facilitates x-ray imaging through its centre. The authors compared the performance of the WFG to that of a standard field generator (SFG) under the influence of the C-arm. Both accuracy and robustness measurements were performed with the C-arm in different positions and poses. Results: The system was deemed robust for both field generators, but the accuracy was notably influenced as the C-arm was moved into the electromagnetic field. The SFG provided a smaller root-mean-square position error but was more influenced by the C-arm than the WFG. The WFG also produced smaller maximum and variance of the error. Conclusions: Electromagnetic (EM) tracking with the new WFG during C-arm based fluoroscopy guidance seems to be a step forward, and with a correction scheme implemented it should be feasible.

  9. Electromagnetic Confined Plasma Target for Interaction Studies with Intense Laser Fields

    SciTech Connect

    Zielbauer, B; Ursescu, U; Trotsenko, S; Spillmann, U; Schuch, R; Stohlker, T; Kuhl, T; Borneis, S; Schenkel, T; McDonald, J; Schneider, D

    2006-08-09

    The paper describes a novel application of an electron beam ion trap as a plasma target facility for intense laser-plasma interaction studies. The low density plasma target ({approx}10{sup 13}/cm{sup 3}) is confined in a mobile cryogenic electromagnetic charged particle trap, with the magnetic confinement field of 1-3T maintained by a superconducting magnet. Ion plasmas for a large variety of ion species and charge states are produced and maintained within the magnetic field and the space charge of an energetic electron beam in the ''Electron Beam Ion Trap'' (EBIT) geometry. Intense laser beams (optical lasers, x-ray lasers and upcoming ''X-Ray Free Electron Lasers'' (XFEL)) provide strong time varying electromagnetic fields (>10{sup 12} V/cm in femto- to nano-sec pulses) for interactions with electromagnetically confined neutral/non-neutral plasmas. The experiments are aimed to gain understanding of the effects of intense photon fields on ionization/excitation processes, the ionization balance, as well as photon polarization effects. First experimental scenarios and tests with an intense laser that utilize the ion plasma target are outlined.

  10. Dynamics of resonant magnetic field penetration and plasma rotation

    NASA Astrophysics Data System (ADS)

    Ivanov, N. V.; Kakurin, A. M.

    2017-01-01

    Results of calculations and analysis of the penetration of resonant magnetic perturbations (RMP) into tokamak plasma are presented. The TEAR code used for the calculations is based on a two-fluid magnetohydrodynamics approximation that gives coupled diffusion-type equations for the magnetic flux perturbation and for plasma rotation velocities in toroidal and poloidal directions. The radial distribution of the magnetic flux perturbation is calculated taking account of an externally applied RMP and magnetic perturbation generated by an eddy current in the resistive-vacuum vessel. The decoupling of magnetic-island velocity from the velocity of plasma rotation is employed in the calculations according to available experimental evidence and corresponding theoretical understanding. The account of this decoupling, as well as of plasma rotation in the poloidal direction in addition to the toroidal one, reduces the RMP penetration threshold and accelerates the penetration process. The main attention is paid to the dependences of the RMP penetration dynamics on the simulation conditions. The simulation findings are compared with available experimental data. Some predictions of the penetration threshold values for ITER conditions are presented.

  11. Radio Frequency Trap for Containment of Plasmas in Antimatter Propulsion Systems Using Rotating Wall Electric Fields

    NASA Technical Reports Server (NTRS)

    Sims, William Herbert, III (Inventor); Martin, James Joseph (Inventor); Lewis, Raymond A. (Inventor)

    2003-01-01

    A containment apparatus for containing a cloud of charged particles comprises a cylindrical vacuum chamber having a longitudinal axis. Within the vacuum chamber is a containment region. A magnetic field is aligned with the longitudinal axis of the vacuum chamber. The magnetic field is time invariant and uniform in strength over the containment region. An electric field is also aligned with the longitudinal axis of the vacuum chamber and the magnetic field. The electric field is time invariant, and forms a potential well over the containment region. One or more means are disposed around the cloud of particles for inducing a rotating electric field internal to the vacuum chamber. The rotating electric field imparts energy to the charged particles within the containment region and compress the cloud of particles. The means disposed around the outer surface of the vacuum chamber for inducing a rotating electric field are four or more segments forming a segmented ring, the segments conforming to the outer surface of the vacuum chamber. Each of the segments is energized by a separate alternating voltage. The sum of the voltages imposed on each segment establishes the rotating field. When four segments form a ring, the rotating field is obtained by a signal generator applying a sinusoidal signal phase delayed by 90,180 and 270 degrees in sequence to the four segments.

  12. [Physical model of the plant tissue response to exposure to the microwave electromagnetic field].

    PubMed

    Kalinin, L G; Boshkova, I L

    2003-01-01

    A hypothesis was suggested to explain the effect of biostimulation of seeds exposed to microwave electromagnetic field. It was shown that the assumption on the determining influence of the microwave field on the transport properties of the conducting system of a plant satisfactorily explains the phenomena observed in germinating seeds and growing plants. A physical model of the response of a plant cell to a microwave field is presented, which served as a basis for the method of calculating the maximum possible time of exposure of plant tissue.

  13. Susceptibility of the QCD vacuum to CP-odd electromagnetic background fields.

    PubMed

    D'Elia, Massimo; Mariti, Marco; Negro, Francesco

    2013-02-22

    We investigate two flavor quantum chromodynamics (QCD) in the presence of CP-odd electromagnetic background fields and determine, by means of lattice QCD simulations, the induced effective θ term to first order in E[over →] · B[over →]. We employ a rooted staggered discretization and study lattice spacings down to 0.1 fm and Goldstone pion masses around 480 MeV. In order to deal with a positive measure, we consider purely imaginary electric fields and real magnetic fields, and then exploit the analytic continuation. Our results are relevant to a description of the effective pseudoscalar quantum electrodynamics-QCD interactions.

  14. Electromagnetically induced transparency in an asymmetric double quantum well under non-resonant, intense laser fields

    NASA Astrophysics Data System (ADS)

    Niculescu, E. C.

    2017-02-01

    Electromagnetically induced transparency in an asymmetric double quantum well subjected to a non-resonant, intense laser field is theoretically investigated. We found that the energy levels configuration could be switched between a Λ-type and a ladder-type scheme by varying the non-resonant radiation intensity. This effect is due to the laser-induced electron tunneling between the wells and it allows a substantial flexibility in the manipulation of the optical properties. The dependence of the susceptibilities on the control field Rabi frequency, intensity of the nonresonant laser, and the control field detuning for both configurations are discussed and compared.

  15. Explicit high-order symplectic integrators for charged particles in general electromagnetic fields

    NASA Astrophysics Data System (ADS)

    Tao, Molei

    2016-12-01

    This article considers non-relativistic charged particle dynamics in both static and non-static electromagnetic fields, which are governed by nonseparable, possibly time-dependent Hamiltonians. For the first time, explicit symplectic integrators of arbitrary high-orders are constructed for accurate and efficient simulations of such mechanical systems. Performances superior to the standard non-symplectic method of Runge-Kutta are demonstrated on two examples: the first is on the confined motion of a particle in a static toroidal magnetic field used in tokamak; the second is on how time-periodic perturbations to a magnetic field inject energy into a particle via parametric resonance at a specific frequency.

  16. Study of Kink Modes and Error Fields using Rotation Control with a Biased Probe

    NASA Astrophysics Data System (ADS)

    Stoafer, Chris C.; Levesque, J. P.; Peng, Q.; Mauel, M. E.; Navratil, G. A.

    2015-11-01

    A bias probe has been installed in the High Beta Tokamak - Extended Pulse (HBT-EP) for studying MHD mode rotation and stability. When the probe is inserted into the edge of the plasma and a voltage applied, the rotation of long-wavelength kink instabilities is strongly modified. A large poloidal plasma flow results, measured with a bi-directional Mach probe, and changes in plasma flow correlate to changes in edge kink mode rotation. An active controller is used to adjust the probe voltage in real time for controlling both the plasma flow and mode rotation. Bias probe voltages are generated through an active GPU-based digital feedback system. Mode rotation control is desirable and allows for MHD stability studies under conditions of varying mode rotation rates. At large positive biases, the probe current induces a torque that opposes the natural direction of mode rotation. We are able to apply sufficiently large torque to induce a transition to a fast rotation state (both mode and plasma rotation). The bias required to induce the transition is shown to depend on an applied error field, establishing a technique to determine the natural error field on HBT-EP. Supported by U.S. DOE Grant DE-FG02-86ER53222.

  17. Mesenchymal stem cells that located in the electromagnetic fields improves rat model of Parkinson’s disease

    PubMed Central

    Jadidi, Majid; Biat, Saeed Moghadas; Sameni, Hamid Reza; Safari, Manouchehr; Vafaei, Abbas Ali; Ghahari, Laya

    2016-01-01

    Objective(s): The main characteristic of mesenchymal stem cells (MSCs) is their ability to produce other cell types. Electromagnetic field (EMF) stimulates differentiation of MSCs into other cells. In this study, we investigated whether EMF can effect on the differentiation of MSCs into dopaminergic (DA) neurons. Materials and Methods: An EMF with a frequency of 50 Hz and two intensities of 40 and 400 µT 1hr/day was generated around the cells for a week. Afterwards, these cells were injected into the left ventricle of Parkinsonian rats. The rats survived for 2 weeks, and then sampling was performed. Results: The injected cells differentiated into DA neurons and sporadically settled in the substantia nigra pars compacta (SNpc). Transplanted rats exhibited significant partial correction apomorphine-induced rotational behavior compared to Parkinsonian rats (5.0±0.1 vs 7.57±0.08). Results demonstrated that endogenous serum and brain derived neurotrophic factor (BDNF) were altered in all experimental groups. The greatest increase was in group of 400 µT EMF in comparison with Parkinsonian rats (398±15 vs. 312±11.79 pg ⁄ mg). Current study have shown that 6-Hydroxydopamine can cause severe loss of dopaminergic neurons (68±6.58), but injected MSCs that exposed to 40 and 400 µT EMF increased dopaminergic neurons in SNpc (108±2.33 & 126±3.89) (P<0.001). Conclusion: Electromagnetic fields with particular frequencies stimulate MSCs. So, these cells had anti-Parkinsonian properties in our studies. PMID:27635198

  18. Faraday Rotation Measure Gradients from a Helical Magnetic Field in 3C273

    SciTech Connect

    Zavala, Robert T.; Taylor, G.B.; /NRAO, Socorro /KIPAC, Menlo Park

    2005-06-06

    Using high frequency (12-22 GHz) VLBA observations we confirm the existence of a Faraday rotation measure gradient of {approx}500 rad m{sup -2} mas{sup -1} transverse to the jet axis in the quasar 3C273. The gradient is seen in two epochs spaced roughly six months apart. This stable transverse rotation measure gradient is expected if a helical magnetic field wraps around the jet. The overall order to the magnetic field in the inner projected 40 parsecs is consistent with a helical field. However, we find an unexpected increase in fractional polarization along the edges of the source, contrary to expectations. This high fractional polarization rules out internal Faraday rotation, but is not readily explained by a helical field. After correcting for the rotation measure, the intrinsic magnetic field direction in the jet of 3C273 changes from parallel to nearly perpendicular to the projected jet motion at two locations. If a helical magnetic field causes the observed rotation measure gradient then the synchrotron emitting electrons must be separate from the helical field region. The presence or absence of transverse rotation measure gradients in other sources is also discussed.

  19. Delineation of electric and magnetic field effects of extremely low frequency electromagnetic radiation on transcription

    SciTech Connect

    Greene, J.J.; Skowronski, W.J.; Mullins, J.M.; Nardone, R.M.; Penafiel, M.; Meister, R. )

    1991-01-31

    The relative effects of the electric and magnetic field components of extremely low frequency electromagnetic radiation (ELF) on transcription were examined in human leukemia HL-60 cells. Delineation of the individual field contributions was achieved by irradiating cells in separate concentric compartments of a culture dish within a solenoid chamber. This exposure system produced a homogeneous magnetic field with a coincident electric field whose strength varied directly with distance from the center of the culture dish. Irradiation of HL-60 cells with sine wave ELF at 60 Hz and a field strength of 10 Gauss produced a transient increase in the transcriptional rates which reached a maximum of 50-60% enhancement at 30-120 minutes of irradiation and declined to near basal levels by 18 hours. Comparison of transcription responses to ELF of cells in different concentric compartments revealed that the transcriptional effects were primarily the result of the electric field component with little or no contribution from the magnetic field.

  20. Investigating the impact of electromagnetic fields on human cells: A thermodynamic perspective

    NASA Astrophysics Data System (ADS)

    Lucia, Umberto; Ponzetto, Antonio; Deisboeck, Thomas S.

    2016-02-01

    The consequences of the interactions of electromagnetic waves, as used in conventional MRI technology, with human cells are not fully understood. To analyze these interactions, a novel thermodynamic approach is presented that is based on the relationship between electromagnetic and thermodynamic quantities. The theoretical results indicate that the waves' impact is largest at high magnetic field strengths and at low frequencies. This is the first step towards a clinically useful framework to quantitatively assess MRI impact including a potential trade-off between the desired increase in spatial resolution that higher magnetic field strengths yield for diagnostic purposes and the danger this may pose for cell membranes, and by extension, for the tissues investigated.