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Last update: November 12, 2013.
1

Electromagnets  

NSDL National Science Digital Library

In this investigation, students will construct electromagnets and test to see which variables make them stronger. Although elementary and middle school teachers are expected to have done this activity with their classes, teachers of younger students often

Horton, Michael

2009-05-30

2

Electromagnets  

NSDL National Science Digital Library

In this activity, the students will complete the grand challenge and design an electromagnet to separate steel from aluminum for the recycler. In order to do this, students compare the induced magnetic field of an electric current with the magnetic field of a permanent magnet and must make the former look like the latter. They discover that looping the current produces the desired effect and find ways to further strengthen the magnetic field.

Vu Bioengineering Ret Program

3

ELECTROMAGNETIC PUMP  

DOEpatents

This patent reiates to electromagnetic pumps for electricity-conducting fluids and, in particular, describes several modifications for a linear conduction type electromagnetic interaction pump. The invention resides in passing the return conductor for the current traversing the fiuid in the duct back through the gap in the iron circuit of the pump. Both the maximum allowable pressure and the efficiency of a linear conduction electromagnetic pump are increased by incorporation of the present invention.

Pulley, O.O.

1954-08-17

4

Electromagnetic fasteners  

SciTech Connect

An electromagnetic fastener for manipulating objects in space uses the matic attraction of various metals. An end effector is attached to a robotic manipulating system having an electromagnet such that when current is supplied to the electromagnet, the object is drawn and affixed to the end effector, and when the current is withheld, the object is released. The object to be manipulated includes a multiplicity of ferromagnetic patches at various locations to provide multiple areas for the effector on the manipulator to become affixed to the object. The ferromagnetic patches are sized relative to the object's geometry and mass.

Crane, Randolph W. (Idaho Falls, ID); Marts, Donna J. (Idaho Falls, ID)

1994-01-01

5

Electromagnetic Scattering.  

National Technical Information Service (NTIS)

This report summarizes research results produced by the investigator under support of the Air Force grant. The work has been mainly concerned with the scattering of electromagnetic waves by bounded bodies of small electrical dimensions, but with some cons...

T. B. A. Senior

1983-01-01

6

Electromagnetic Fields  

MedlinePLUS

... off radio-frequency energy (RF), a form of electromagnetic radiation. Scientists need to do more research on this before they can say for sure. NIH: National Institute of Environmental Health Sciences

7

Electromagnetic Hypersensitivity  

Microsoft Academic Search

\\u000a Electromagnetic hypersensitive persons (EHS) attribute their nonspecific health symptoms to environmental electromagnetic\\u000a fields (EMF) of different sources in or outside their homes. In general, causal attribution is not restricted to specific\\u000a EMF frequencies but involves a wide range from extremely low frequencies (ELF) up to radio frequencies (RF) including mobile\\u000a telecommunication microwaves and radar. EHS argue that existing exposure limits

Norbert Leitgeb

8

Electromagnet Lesson  

NSDL National Science Digital Library

This hands-on classroom activity will help students understand the connections between magnets and electricity generation. The learning cycle planner includes an exploration phase with a hands-on activity and a suggested video. The concept development phase suggests showing the film "Who Killed the Electric Car?" The main part of this learning unit is the electromagnet lesson, which is a two day small group activity in which students will create an electromagnet. This document may be downloaded in PDF file format; student worksheets are included.

Orzali, Joe

2011-12-08

9

Electromagnetic scattering  

Microsoft Academic Search

This report summarizes research results produced by the investigator under support of the Air Force grant. The work has been mainly concerned with the scattering of electromagnetic waves by bounded bodies of small electrical dimensions, but with some consideration also of acoustic scattering by soft, hard and homogeneous penetrable shapes.

T. B. A. Senior

1983-01-01

10

Electromagnetic Survey  

USGS Multimedia Gallery

USGS hydrologist conducts a broadband electromagnetic survey in New Orleans, Louisiana. The survey was one of several geophysical methods used during USGS applied research on the utility of the multi-channel analysis of surface waves (MASW) seismic method for non-invasive assessment of earthen levee...

2009-05-01

11

Electromagnetic launcher  

Microsoft Academic Search

This paper describes an electromagnetic launcher. It comprises: a stationary superconductive coil situated coaxially in a cylindrical vacuum vessel for providing a magnetic field. The superconductive coil having a central aperture, the vacuum vessel having an axially extending bore passing through the central aperture of the superconducting coil; a resistive coil situated coaxially with the superconductive coil and movable axially

E. T. Laskaris; M. V. K. Chari

1990-01-01

12

Electromagnetic Interference and Electromagnetic Compatibility Test Technology  

Microsoft Academic Search

With the extensive application of electronic equipment, issues from electromagnetic compatibility caused by electromagnetic interference will directly affect the normal operation of the system or equipment. In this paper, the electromagnetic interference on the basis of research and analysis the two typical interference source-- the inverter and microwave ovens, to discuss the mechanism and performance of electromagnetic and microwave radiation,

Feng Lv; Hua Zhao; Wenxia Du; Huilong Jin

2010-01-01

13

Electromagnetic leptogenesis  

SciTech Connect

We present a new leptogenesis scenario, where the lepton asymmetry is generated by CP-violating decays of heavy electroweak singlet neutrinos via electromagnetic dipole moment couplings to the ordinary light neutrinos. Akin to the usual scenario where the decays are mediated through Yukawa interactions, we have shown, by explicit calculations, that the desired asymmetry can be produced through the interference of the corresponding tree-level and one-loop decay amplitudes involving the effective dipole moment operators. We also find that the relationship of the leptogenesis scale to the light neutrino masses is similar to that for the standard Yukawa-mediated mechanism.

Bell, Nicole F.; Law, Sandy S. C. [School of Physics, University of Melbourne, Victoria 3010 (Australia); Kayser, Boris J. [Theoretical Physics Department, Fermilab, PO Box 500, Batavia, Illinois 60510-0500 (United States)

2008-10-15

14

Electromagnetic microactuators  

NASA Astrophysics Data System (ADS)

High precision microactuators have become key elements for many applications of MEMS, for example for positioning and handling systems as well as for microfluidic devices. Electromagnetic microactuators exhibit considerable benefits such as high forces, large deflections, low input impedances and thus, the involvement of only low voltages. Most of the magnetic microactuators developed so far are based on the variable reluctance principle and use soft magnetic materials. Since the driving force of such actuators is proportional to their volume, they require structures with rather great heights and aspect ratios. Therefore, the development of new photo resists, which allow UV exposure of thick layers of resist, has been essential for the advancement of variable reluctance microactuators. On the other hand, hard magnetic materials have the potential for larger forces and larger deflections. Accordingly, polymer magnets, in which micro particles of hard magnetic material are suspended in a polymer matrix, have been used to fabricate permanent magnet microactuators. In this paper we give an overview of sophisticated electromagnetic microactuators which have been developed in our laboratory in the framework of the Collaborative Research Center "Design and Manufacturing of Active Microsystems". In particular, concept, fabrication and test of variable reluctance micro stepper motors, of permanent magnet synchronous micromotors and of microactuators based on the Lorentz force principle will be described. Special emphasis will be given to applications in lab-on-chip systems.

Büttgenbach, S.; Al-Halhouli, A. T.; Feldmann, M.; Seidemann, V.; Waldschik, A.

2013-05-01

15

Electromagnetic calorimetry  

NASA Astrophysics Data System (ADS)

Electromagnetic calorimetry forms a key element of almost all current high energy particle physics detectors and has widespread application in related experimental fields such as nuclear physics and astro-particle physics. It will play a particularly important role in the latest generation of experiments at the CERN Large Hadron Collider (LHC), where it is expected that high energy electrons and photons will provide some of the clearest signatures for new discoveries. This article introduces the basic concepts underlying electromagnetic calorimetry and illustrates how these principles have been applied in recent and current detector designs, explaining the connection between technical choices and specific physics goals. Designs are described in sufficient detail to demonstrate the compromises that have to be made in achieving optimum performance within practical constraints. The main emphasis is on the LHC experiments, which provide outstanding examples of the state-of-the-art. Selected examples from other domains, such as nuclear physics and neutrino experiments are also considered and particular attention is given to calorimeter design studies for the proposed International Linear Collider (ILC) where the concept of Particle Flow Analysis is being used as a guiding influence in the overall detector optimization.

Brown, R. M.; Cockerill, D. J. A.

2012-02-01

16

Electromagnetic Topology: Characterization of Internal Electromagnetic Coupling.  

National Technical Information Service (NTIS)

The main principles are presented of a method dealing with the resolution of electromagnetic internal problems: Electromagnetic Topology. A very interesting way is to generalize the multiconductor transmission line network theory to the basic equation of ...

J. P. Parmantier J. P. Aparicio F. Faure

1991-01-01

17

Electromagnetic topology: Characterization of internal electromagnetic coupling  

Microsoft Academic Search

The main principles are presented of a method dealing with the resolution of electromagnetic internal problems: Electromagnetic Topology. A very interesting way is to generalize the multiconductor transmission line network theory to the basic equation of the Electromagnetic Topology: the BLT equation. This generalization is illustrated by the treatment of an aperture as a four port junction. Analytical and experimental

J. P. Parmantier; J. P. Aparicio; F. Faure

1991-01-01

18

Electromagnetic topology - Characterization of internal electromagnetic coupling  

Microsoft Academic Search

This paper presents the main principles of a method dealing with the resolution of electromagnetic internal problems: electromagnetic topology. A very interesting way is to generalize the multiconductor transmission line network theory to the basic equation of electromagnetic topology. This generalization is illustrated by the treatment of an aperture as a four port junction. Analytical and experimental derivations of the

J. P. Parmantier; J. P. Aparicio; F. Faure

1991-01-01

19

Electromagnetic Pulse Rotary Seal.  

National Technical Information Service (NTIS)

An rotary seal for protection against electromagnetic interference and electromagnetic pulses is disclosed. An electrically conductive resilient bellows surrounds a shaft extending through an opening in an enclosure. The bellows is attached at one end to ...

C. W. Neher

1987-01-01

20

The Electromagnetic Spectrum  

NSDL National Science Digital Library

This web site contains materials about all parts of the electromagnetic spectrum. It describes each space telescope that NASA has launched as well as its observing range in the electromagnetic spectrum.

Astrophysics, Laboratory F.

2004-11-17

21

The Electromagnetic Spectrum: FRONTLINE  

NSDL National Science Digital Library

This video segment adapted from FRONTLINE introduces the electromagnetic spectrum and explains how the various types of electromagnetic waves are distinguished by the amount of energy each wave carries.

Foundation, Wgbh E.

2004-02-20

22

Electromagnetic remote sensing. Low frequency electromagnetics  

NASA Astrophysics Data System (ADS)

A series of lectures are presented on the topic of the location and identification of compact objects by low frequency electromagnetics. These lectures were presented as a portion of two graduate level courses in electrical engineering at the University of Toronto in 1985 and 1987. Magnetostatics, electrostatics and electromagnetic induction techniques are discussed in detail.

McFee, John E.

1989-01-01

23

Electromagnetic Interference (Emi)  

Microsoft Academic Search

\\u000a Electric and magnetic signals originating outside of a defibrillator may affect its operation, a phenomenon known as electromagnetic\\u000a interference (EMI). EMI usually refers to interference from environmental electromagnetic instrumentation and should be distinguished\\u000a from other sources of electromagnetic noise causing ICD malfunction (Table 1). Signals most likely to penetrate and affect\\u000a pacemakers and ICDs are electromagnetic waves or signals at

Mike Hardage; Philip D. Henry

24

Composite electromagnetic pulse threat  

Microsoft Academic Search

A new electromagnetic pulse threat based on a composite ambient field defined by a combination of lightning, NEMP (nuclear electromagnetic pulse) and microwave threats is discussed. The composite electromagnetic pulse threat has been used to harden a military helicopter. The hardening to a composite threat resulted in the development of simplified hardening verification procedures. It also provided an economical advantage

A. S. Podgorski

1990-01-01

25

Composite electromagnetic pulse threat  

Microsoft Academic Search

A new electromagnetic pulse threat that is based on a composite ambient field defined by a combination of lightning, NEMP (nuclear electromagnetic pulse) and microwave threats is discussed. The composite electromagnetic pulse threat has been used to harden a military helicopter. The hardening to a composite threat resulted in the development of simplified hardening verification procedures. It also provided an

Andrew S. Podgorski

1990-01-01

26

Electromagnetic Radiation: On Trial  

NSDL National Science Digital Library

This activity introduces students to the properties of electromagnetic radiation in a variety of ways. For example, they put the different types of the electromagnetic radiation on trial, selecting the judge, prosecutor, defense counsel, and jury, and learning about electromagnetic energy by arguing the pros and cons of each wavelength. During this activity, students are introduced to the general properties of electromagnetic waves, learn to analyze the relation between the specific properties of waves and their position in the electromagnetic spectrum, and discuss methods used to detect and analyze different waves. Students also learn about scientists whose work contributed to our understanding of electromagnetic energy. Students are encouraged to use an electronic bulletin board to communicate with each other, posting insights, ideas, evidence and questions on electromagnetic energy.

2007-05-16

27

Electromagnetic cellular interactions.  

PubMed

Chemical and electrical interaction within and between cells is well established. Just the opposite is true about cellular interactions via other physical fields. The most probable candidate for an other form of cellular interaction is the electromagnetic field. We review theories and experiments on how cells can generate and detect electromagnetic fields generally, and if the cell-generated electromagnetic field can mediate cellular interactions. We do not limit here ourselves to specialized electro-excitable cells. Rather we describe physical processes that are of a more general nature and probably present in almost every type of living cell. The spectral range included is broad; from kHz to the visible part of the electromagnetic spectrum. We show that there is a rather large number of theories on how cells can generate and detect electromagnetic fields and discuss experimental evidence on electromagnetic cellular interactions in the modern scientific literature. Although small, it is continuously accumulating. PMID:20674588

Cifra, Michal; Fields, Jeremy Z; Farhadi, Ashkan

2010-07-30

28

Perfect electromagnetic conductor  

Microsoft Academic Search

In differential-form representation, the Maxwell equations are represented by simple differential relations between the electromagnetic two-forms and source three-forms while the electromagnetic medium is defined through a constitutive relation between the two-forms. The simplest of such relations expresses the electromagnetic two-forms as scalar multiples of one another. Because of its strange properties, the corresponding medium has been considered as nonphysical.

Ismo V. Lindell; Ari Sihvola

2005-01-01

29

Electromagnetically Operated Counter  

DOEpatents

An electromagnetically operated counter wherein signals to be counted are applied to cause stepwise rotation of a rotatable element which is connected to a suitable register. The mechanism involved consists of a rotatable armature having three spaced cores of magnetic material and a pair of diametrically opposed electromagnets with a suitable pulsing circuit to actuate the magnets.

Goldberg, H.D.; Goldberg, M.I.

1950-01-31

30

Introducing Electromagnetic Field Momentum  

ERIC Educational Resources Information Center

|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…

Hu, Ben Yu-Kuang

2012-01-01

31

Photonic electromagnetic field probes  

Microsoft Academic Search

Summary form only given. Optically sensed probes designed to accurately measure electromagnetic fields are described. The probes use passive electrooptic modulators of Pockels cell or integrated optics designs to transfer the electromagnetic signal to an optical carrier propagating in a fibre-optic link. This approach eliminates the need for active components or power sources in the probe head. It minimizes the

M. Kanda; K. D. Masterson; D. R. Novotny

1992-01-01

32

Low frequency electromagnetic devices  

Microsoft Academic Search

The design, simulation and implementation of low frequency electromagnetic devices on planar structures are given. Planar devices and components are designed and built on a ceramic-based material that allowed a surface-mount (SMT) application. Method of moment based electromagnetic field solvers are used to verify the design of the devices. Planar devices and components are then implemented and tested. Simulation results

Abdullah Eroglu

2009-01-01

33

Tunability enhanced electromagnetic wiggler  

DOEpatents

The invention discloses a wiggler used in synchrotron radiation sources and free electron lasers, where each pole is surrounded by at least two electromagnetic coils. The electromagnetic coils are energized with different amounts of current to provide a wide tunable range of the on-axis magnetic flux density, while preventing magnetic saturation of the poles.

Schlueter, R.D.; Deis, G.A.

1991-03-20

34

Tunability enhanced electromagnetic wiggler  

DOEpatents

The invention discloses a wiggler used in synchrotron radiation sources and free electron lasers, where each pole is surrounded by at least two electromagnetic coils. The electromagnetic coils are energized with different amounts of current to provide a wide tunable range of the on-axis magnetic flux density, while preventing magnetic saturation of the poles. 14 figs.

Schlueter, R.D.; Deis, G.A.

1992-03-24

35

The Electromagnetic Spectrum  

NSDL National Science Digital Library

This tutorial introduces students to the concepts of electromagnetic waves, wavelength, and the electromagnetic spectrum. Diagrams and written descriptions explain how wavelength is measured and explore the traditional divisions of the spectrum: radio, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

36

Tunability enhanced electromagnetic wiggler  

DOEpatents

The invention discloses a wiggler used in synchrotron radiation sources and free electron lasers, where each pole is surrounded by at least two electromagnetic coils. The electromagnetic coils are energized with different amounts of current to provide a wide tunable range of the on-axis magnetic flux density, while preventing magnetic saturation of the poles.

Schlueter, Ross D. (Albany, CA); Deis, Gary A. (Livermore, CA)

1992-01-01

37

Building an Electromagnet  

NSDL National Science Digital Library

Students design and construct an electromagnet that must pick up 10 staples. They begin with only minimal guidance, and after the basic concept is understood, are informed of the properties that affect the strength of that magnet. They conclude by designing their own electromagnet to complete the challenge of separating scrap steel from scrap aluminum for recycling and share it with the class.

Vu Bioengineering Ret Program

38

Electromagnetic Interference Prediction in Transient Electromagnetic Environment  

Microsoft Academic Search

This paper presents an approach to predict the interference effects of a transient electromagnetic environment (EME) caused by an aggregate of wideband transmitters on a traditional narrowband victim. Due to the constraint of the narrowband receiver, it is sufficient to evaluate such wideband parameters of transmitter as effective isotropically radiated average power (EIRP) and antenna gains, etc. at the center

Yu Zhi-yong; Wang Jiang-feng

2007-01-01

39

What Are Electromagnetic Fields?  

MedlinePLUS

... the main sources of IF fields; and radio, television, radar and cellular telephone antennas, and microwave ovens ... environments.) Electromagnetic fields at high frequencies Mobile telephones, television and radio transmitters and radar produce RF fields. ...

40

Electromagnetically Induced Transparency.  

National Technical Information Service (NTIS)

We report the first observation of electromagnetically induced transparency in optically thick medium. The transparency results from a destructive interference of two dressed states which are created by applying a temporally smooth coupling laser between ...

A. Imamoglu K. J. Boiler S. E. Harris

1992-01-01

41

Electrodeless Electromagnetic Blood Flowmeter.  

National Technical Information Service (NTIS)

The report presents an evaluation of two electrodeless electromagnetic blood flowmeters which circumvent the electrode-tissue interface problem. The flowmeter establishes a traveling magnetic field, and the flow rate is then determined by using a pickup c...

E. S. Pierson F. N. Huffman

1969-01-01

42

Identifying Electromagnetic Attacks against Airports  

NASA Astrophysics Data System (ADS)

This work presents a new and sophisticated approach to detect and locate the origin of electromagnetic attacks. At the example of an airport, a normal electromagnetic environment is defined, in which electromagnetic attacks shall be identified. After a brief consideration of the capabilities of high power electromagnetic sources to produce high field strength values, this contribution finally presents the approach of a sensor network, realizing the identification of electromagnetic attacks.

Kreth, A.; Genender, E.; Doering, O.; Garbe, H.

2012-05-01

43

Electromagnetic navigation guided bronchoscopy  

PubMed Central

Abstract This review describes the technique and applications of an emerging bronchoscopic approach utilizing three-dimensional reconstructions of chest computed tomography scans to facilitate electromagnetic guidance to peripheral lung nodules. This approach, electromagnetic navigation bronchoscopy, is useful for biopsy, placement of fiducial markers, or dye marking of overlying pleura prior to thoracoscopic wedge resection. This technique offers some potential advantages over other forms of biopsy. The design, application, relative advantages and pitfalls of this system are the subject of this review.

2009-01-01

44

Electromagnetic rotational actuation.  

SciTech Connect

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.

Hogan, Alexander Lee

2010-08-01

45

New electromagnetic conservation laws  

Microsoft Academic Search

The Chevreton superenergy tensor was introduced in 1964 as a counterpart, for electromagnetic fields, of the well-known Bel-Robinson tensor of the gravitational field. We here prove the unnoticed facts that, in the absence of electromagnetic currents, Chevreton's tensor (i) is completely symmetric, and (ii) has a trace-free divergence if the Einstein-Maxwell equations hold. It follows that the trace of the

G. Bergqvist; I. Eriksson; J. M. M. Senovilla

2003-01-01

46

Environmental and space electromagnetics  

Microsoft Academic Search

The present volume on environmental and space electromagnetics discusses spacecraft EM environment, natural and triggered lightning, atmospherics, whistlers, and emissions, and natural VLF\\/ELF radio noise. Attention is given to terrestrial and extraterrestrial noise environment, planetary lightning and cosmic plasma noise, noise and communication statistics, and space communication and measurement. Topics addressed include high-power electromagnetics, seismoelectric emissions, ball lightning, and meteorologico-electric

Hiroshi Kikuchi

1991-01-01

47

Metamaterial electromagnetic wave absorbers.  

PubMed

The advent of negative index materials has spawned extensive research into metamaterials over the past decade. Metamaterials are attractive not only for their exotic electromagnetic properties, but also their promise for applications. A particular branch-the metamaterial perfect absorber (MPA)-has garnered interest due to the fact that it can achieve unity absorptivity of electromagnetic waves. Since its first experimental demonstration in 2008, the MPA has progressed significantly with designs shown across the electromagnetic spectrum, from microwave to optical. In this Progress Report we give an overview of the field and discuss a selection of examples and related applications. The ability of the MPA to exhibit extreme performance flexibility will be discussed and the theory underlying their operation and limitations will be established. Insight is given into what we can expect from this rapidly expanding field and future challenges will be addressed. PMID:22627995

Watts, Claire M; Liu, Xianliang; Padilla, Willie J

2012-05-25

48

Electromagnetic properties of baryons  

SciTech Connect

We discuss the chiral behavior of the nucleon and {Delta}(1232) electromagnetic properties within the framework of a SU(2) covariant baryon chiral perturbation theory. Our one-loop calculation is complete to the order p{sup 3} and p{sup 4}/{Delta} with {Delta} as the {Delta}(1232)-nucleon energy gap. We show that the magnetic moment of a resonance can be defined by the linear energy shift only when an additional relation between the involved masses and the applied magnetic field strength is fulfilled. Singularities and cusps in the pion mass dependence of the {Delta}(1232) electromagnetic moments reflect a non-fulfillment. We show results for the pion mass dependence of the nucleon iso-vector electromagnetic quantities and present preliminary results for finite volume effects on the iso-vector anomalous magnetic moment.

Ledwig, T.; Pascalutsa, V.; Vanderhaeghen, M. [Institut fuer Kernphysik, Universitaet Mainz, D-55099 Mainz (Germany); Martin-Camalich, J. [Departamento de Fisica Teorica and IFIC, Universidad de Valencia-CSIC, Spain and Department of Physics and Astronomy, University of Sussex, BN1 9Qh, Brighton (United Kingdom)

2011-10-21

49

Gravitation electromagnetic theory  

NASA Astrophysics Data System (ADS)

The interrelationship existing between gravitation and electromagnetism is examined. A brief summary of the ideas which have guided scientific thought toward an understanding of gravitation is presented. The development of the electromagnetic theory is presented. The effects of the action of electromagnetic fields on the gravitational interactions are shown. On one side is, the explanation of various important cosmological phenomena, and on the other side, the path to control the gravitational interaction, which will foster the advent of gravitational propulsion, the foundations of which are established. The implications of this theory to the biological field are explored. In this field, the local control of gravitation opens the way to the study of the biological processes under several different conditions of gravity, which, in turn, may bring forth important results in biological research.

Deaquino, Fran

1988-03-01

50

Micronewton electromagnetic thruster  

NASA Astrophysics Data System (ADS)

A low cost and light electromagnetic thruster, consisting in a disc rigidly attached with a coaxial coil, shows steady recoil by losing its linear momentum. The signal applied in the device is a square electric potential. A continuous thrust is observed on the center-of-mass in one single direction under electromagnetic excitation for various voltages and nominal high frequencies. At 1 kHz with 20 V amplitude, the recoil force reaches 4 ?N (micronewton). The recoil is numerically quantified with induced electromotive and Lorentz forces. The presented device directly converts electric energy into kinetic energy.

Charrier, D. S. H.

2012-07-01

51

Introducing electromagnetic field momentum  

NASA Astrophysics Data System (ADS)

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 analysis and without using vector calculus identities or the need to evaluate integrals. I use this result to show that linear and angular momenta are conserved for a charge in the presence of a magnetic dipole when the dipole strength is changed.

Yu-Kuang Hu, Ben

2012-07-01

52

Review of Quantum Electromagnetic States.  

National Technical Information Service (NTIS)

This program provided a review of the conceptual and mathematical apparatus to apply modern theories of electromagnetic fields. As a study in low- noise electromagnetic states, it centers on the need to transition basic physics into the engineering arena ...

M. A. Parker

1999-01-01

53

Torsion and the Electromagnetic Field  

Microsoft Academic Search

In the framework of the teleparallel equivalent of general relativity, we study the dynamics of a gravitationally coupled electromagnetic field. It is shown that the electromagnetic field is able not only to couple to torsion, but also, through its energy-momentum tensor, produce torsion. Furthermore, it is shown that the coupling of the electromagnetic field with torsion preserves the local gauge

V. C. de Andrade; J. G. Pereira

1999-01-01

54

Geometrical Model of Electromagnetic Fields  

Microsoft Academic Search

The electrostatic field, electromagnetic waves, electromagnetic induction, and the pure magnetic field are illustrated and explained in terms of a single pictorial representation of the general electromagnetic field of a classical charged particle. The field of a charged particle is described by the orientation and density of a family of surfaces radially distributed about the path of the particle in

Edward S. Lowry

1963-01-01

55

Electromagnetic Spectrum Management.  

National Technical Information Service (NTIS)

This report presents the results of an Air Force Occupational Survey of the Electromagnetic Spectrum Management career ladder, Air Force Specialty Code (AFSC) 3C1X2. Authority for conducting occupational surveys is contained in AFI 36-2623. Copies of this...

1997-01-01

56

Electromagnetic pulse bombs' defense  

Microsoft Academic Search

With the high power microwave devices development, the high power microwave electromagnetic pulse bombs (E-bombs) have become practical abroad. The development of conventional E-bombs devices allows their use in nonnuclear confrontations. E-bombs are powerful enough to damage communication, radar, navigation and computer systems. This paper discusses effects of EMP on electrical system and how to defend the EMP.

Bin Chen; Yongbin Wang; Juan Li; Jianzhong Wang

2007-01-01

57

Differential Forms in Electromagnetics  

NASA Astrophysics Data System (ADS)

An introduction to multivectors, dyadics, and differential forms for electrical engineers While physicists have long applied differential forms to various areas of theoretical analysis, dyadic algebra is also the most natural language for expressing electromagnetic phenomena mathematically. George Deschamps pioneered the application of differential forms to electrical engineering but never completed his work. Now, Ismo V. Lindell, an internationally recognized authority on differential forms, provides a clear and practical introduction to replacing classical Gibbsian vector calculus with the mathematical formalism of differential forms. In Differential Forms in Electromagnetics, Lindell simplifies the notation and adds memory aids in order to ease the reader's leap from Gibbsian analysis to differential forms, and provides the algebraic tools corresponding to the dyadics of Gibbsian analysis that have long been missing from the formalism. He introduces the reader to basic EM theory and wave equations for the electromagnetic two-forms, discusses the derivation of useful identities, and explains novel ways of treating problems in general linear (bi-anisotropic) media. Clearly written and devoid of unnecessary mathematical jargon, Differential Forms in Electromagnetics helps engineers master an area of intense interest for anyone involved in research on metamaterials.

Lindell, Ismo V.

2004-04-01

58

Computation of Electromagnetic Fields  

Microsoft Academic Search

This paper reviews some of the more useful, current and newly developing methods for the solution of electromagnetic fields. It begins with an introduction to numerical methods in general, including specific references to the mathematical tools required for field analysis, e.g., solution of systems of simultaneous linear equations by direct and iterative means, the matrix eigenvalue problem, finite difference differentiation

A. Wexler

1969-01-01

59

Physics 2000: Electromagnetic Waves  

NSDL National Science Digital Library

This website presents the physics of electromagnetic waves by describing the properties of waves, electric forces, force fields, and vibrating charges. Interactive animations and a question and answer "tutorial" format is used to present the information. Presentations about the applications of E&M waves are also included.

Goldman, Martin

2004-07-14

60

Electromagnetic radiation detector  

DOEpatents

An electromagnetic radiation detector including a collimating window, a cathode member having a photoelectric emissive material surface angularly disposed to said window whereby radiation is impinged thereon at acute angles, an anode, separated from the cathode member by an evacuated space, for collecting photoelectrons emitted from the emissive cathode surface, and a negatively biased, high transmissive grid disposed between the cathode member and anode.

Benson, Jay L. (Albuquerque, NM); Hansen, Gordon J. (Albuquerque, NM)

1976-01-01

61

Electromagnetic radiations from rocks  

Microsoft Academic Search

To test the possibility of the emission of electromagnetic waves from rocks, experiments have been made to measure the electric field by using mainly granite samples that were struck together or struck by a hammer or a weight and were fractured by a bending moment. The wide-band (10 Hz to 100 kHz) waveforms of electric signals were digitally recorded. Roughly

Toshio Ogawa; Kazuo Oike; Taiji Miura

1985-01-01

62

Electromagnetic targeting of guns  

SciTech Connect

This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Electromagnetic pulse (EMP) signals produced from explosives being fired have been reported in the literature for fifty years. When a gun is fired it produces an EMP muzzle blast signal. The strength and nature of these signals was first analyzed in the early 1970s, while the results were interesting, no follow-up studies were conducted. With modern detection and signal processing technology, we believe that these signals could be used to instantaneously locate guns of virtually all calibers as they fire. The objective of our one-year project was to establish the basic nature of these signals and their utility in the concept of electromagnetic targeting of guns.

Pogue, E.W.; Boat, R.M.; Holden, D.N.; Lopez, J.R. [and others

1996-10-01

63

Electromagnetic induction spectroscopy  

NASA Astrophysics Data System (ADS)

An object, made partly or wholly of metals, has a distinct combination of electrical conductivity, magnetic permeability, and geometrical shape and size. When the object is exposed to a low-frequency electromagnetic field, it produces a secondary magnetic field. By measuring the secondary field in a broadband spectrum, we obtain a distinct spectral signature that may uniquely identify the object. Based on the response spectrum, we attempt to 'fingerprint' the object. This is the basic concept of Electromagnetic Induction Spectroscopy (EMIS). EMIS technology may be particularly useful for detecting buried landmines and unexploded ordnance. By fully characterizing and identifying an object without excavation. We should be able to reduce significantly the number of false targets. EMIS should be fully applicable to many other problems where target identification and recognition (without intrusive search) are important. For instance, an advanced EMIS device at an airport security gate may be able to recognize a particular weapon by its maker and type.

Won, I. J.; Keiswetter, Dean A.

1998-09-01

64

Electromagnetic field cancer scares.  

PubMed

The internal electric current or power levels that a human is likely to encounter in a typical electromagnetic field environment are calculated. At 60 Hz, a reasonable value for maximum permissible exposure is an internal current density of 1 microA cm(-2). At this frequency, a 600 V m(-1) electric field results in a current density of 0.0002 microA cm(-2), while a 200 microT magnetic field results in 0.6 microA cm(-2). This should be compared with an action potential, which is associated with a current density of 800 microA cm(-2). The ANSI/IEEE C95.1-1991 standards, whose frequency range is 3 kHz to 300 GHz, are examined. Epidemiological studies are briefly considered. The conclusion is that it is highly unlikely that there is a link between electromagnetic fields and cancer. PMID:9228165

Deutsch, S; Wilkening, G M

1997-08-01

65

An electromagnetic micro dynamometer  

Microsoft Academic Search

Performance of a planar magnetic VR micromotor is evaluated using an electromagnetically controlled load and planar gear coupling. Fabrication is based on extended LIGA processing methods. A new coil construction technique is described which uses wound micro-coils on a LIGA defined pre-fonn. A maximum rotational speed of 17,500 rpm is achieved for a 1000 pm diameter rotor with a maximum

T. R. Christenson; J. Klein; H. Guckel

1995-01-01

66

Electromagnetically Activated Hypersonic Ducts  

NASA Astrophysics Data System (ADS)

This paper explores the use of Electromagnetic Radiation as an alternative to combustion in Scramjet-like hypersonic engines. The radiation is absorbed by the flow, heating it and thereby providing an alternative to the heat derived from combustion in the Scramjet. The advantages and disadvantages of this system are explored and theoretical results are presented illustrating typical radiation pathlengths at different frequencies. Suggestions for further theoretical and practical work are also made.

MacLeod, C.

67

Electromagnetic tornadoes in space  

SciTech Connect

The exotic phenomenon of energetic-ion conic formation by plasma waves in the magnetosphere is considered. Two particular transverse heating mechanisms are reviewed in detail; lower-hybrid energization of ions in the boundary layer of the plasma sheet and electromagnetic ion cyclotron resonance heating in the central region of the plasma sheet. Mean particle calculations, plasma simulations and analytical treatments of the heating processes are described.

Chang, T.; Crew, G.B.; Retterer, J.M.

1988-01-01

68

Flash memory electromagnetic compatibility  

Microsoft Academic Search

This paper analyzes the radiated electromagnetic compatibility (EMC) behavior of AMD\\/Spansion Flash memory integrated circuits. Using The Engineering Society For Advanced Mobility Land Sea Air and Space (SAE) J1752\\/3 method, the peak RF noise (EMC with respect to radiated emissions) was measured for various technologies and product features, determining statistically valid sensitivity factors for several independent variables. The findings show

Adam D. Fogle; Don Darling; Richard C. Blish; Gene Daszko

2006-01-01

69

Method of electromagnetic exploration  

SciTech Connect

A method is described of electromagnetic exploration comprising the following steps: obtaining measures of two horizontal components of the earth's magnetic field at each reference sites; obtaining a measure of the vertical component of the earth's magnetic field for at least one exploratory site; and determining a measure of a multidimensional earth resistivity structure by correlating the measures of horizontal and vertical components of the earth's magnetic field.

Nekut, A.G. Jr.

1987-05-05

70

Electromagnetic Nondestructive Evaluation (III)  

Microsoft Academic Search

Within the context of non-destructive testing, the classical `Formulate-Solve-Interpret' model of problem solving becomes `Measure-Recover-Interpret'. But, before one can perform measurements, there must be appropriate instrumentation. In this book on electromagnetic non-destructive evaluation (ENDE) all these aspects (instrumentation, measurement, recovery and interpretation) are treated, though the major emphasis is on the recovery and interpretation aspects. The focus of the book,

R S Anderssen

2000-01-01

71

Electromagnetic polarizabilities of hadrons  

SciTech Connect

Electromagnetic polarizabilities of hadrons are reviewed, after a discussion of classical analogues. Differences between relativistic and non-relativistic approaches can lead to conflicts with conventional nuclear physics sum rules and calculational techniques. The nucleon polarizabilities are discussed in the context of the non-relativistic valence quark model, which provides a good qualitative description. The recently measured pion polarizabilities are discussed in the context of chiral symmetry and quark-loop models. 58 refs., 5 figs.

Friar, J.L.

1988-01-01

72

Hyperphysics: Electromagnetic Waves  

NSDL National Science Digital Library

This Wikipedia page contains a labeled diagram of an electromagnetic wave showing how the electric and magnetic vectors change as a wave moves through space. Text introduces the physics of the wave. Just above the diagram is a map of related concepts, depicted as a network. This page is part of the HyperPhysics Collection, which contains many short, illustrated pages on various areas of physics and astronomy.

Nave, Carl R.

2012-03-25

73

Banded electromagnetic stator core  

DOEpatents

A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figures.

Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.

1994-04-05

74

Banded electromagnetic stator core  

DOEpatents

A stator core for an electromagnetic pump includes a plurality of circumferentially adjoining groups of flat laminations disposed about a common centerline axis and collectively defining a central bore and a discontinuous outer perimeter, with adjacent groups diverging radially outwardly to form V-shaped gaps. An annular band surrounds the groups and is predeterminedly tensioned to clamp together the laminations, and has a predetermined flexibility in a radial direction to form substantially straight bridge sections between the adjacent groups. 5 figs.

Fanning, A.W.; Gonzales, A.A.; Patel, M.R.; Olich, E.E.

1996-06-11

75

Emergent electromagnetism in solids  

NASA Astrophysics Data System (ADS)

The electromagnetic field (EMF) is the most fundamental field in condensed-matter physics. Interaction between electrons, electron-ion interaction and ion-ion interaction are all of electromagnetic origin, while the other three fundamental forces, i.e. the gravitational force and weak and strong interactions, are irrelevant in the energy/length scales of condensed-matter physics. Also the physical properties of condensed matter, such as transport, optical, magnetic and dielectric properties, are almost described as their electromagnetic responses. In addition to this EMF, it often happens that the gauge fields appear as the emergent phenomenon in the low-energy sector due to the projection of the electronic wavefunctions onto the curved manifold of the Hilbert sub-space. These emergent EMFs play important roles in many places in condensed-matter physics including the quantum Hall effect, strongly correlated electrons and also in non-interacting electron systems. In this paper, we describe the fundamental idea behind it and some of its applications studied recently.

Nagaosa, Naoto; Tokura, Yoshinori

2012-01-01

76

Gravitation and electromagnetism  

NASA Astrophysics Data System (ADS)

The theory of general relativity unifies gravitation with the geometry of spacetime by replacing the scalar Newtonian gravitational potential with the symmetric metric tensor gmunu of a four-dimensional general Riemannian manifold by means of the equivalence principle. As is well known, the electromagnetic field has resisted all efforts to be interpreted in terms of the geometrical properties of space-time as well. In this investigation, we show that the electromagnetic field may indeed be given a geometrical interpretation in the framework of a modified version of general relativity - unimodular relativity. According to the theory of unimodular relativity developed by Anderson and Finkelstein, the equations of general relativity with a cosmological constant are composed of two independent equations, one which determines the null-cone structure of space-time, another which determines the measure structure of space-time. The field equations that follow from the restricted variational principle of this version of general relativity only determine the null-cone structure and are globally scale-invariant and scale-free. We show that the electromagnetic field may be viewed as a compensating gauge field that guarantees local scale invariance of these field equations. In this way, Weyl's geometry is revived. However, the two principle objections to Weyl's theory do not apply to the present formulation: the Lagrangian remains first order in the curvature scalar and the non-integrability of length only applies to the null-cone structure.

Bock, Robert Davis

77

Ejs Electromagnetic Wave Model  

NSDL National Science Digital Library

The Ejs Electromagnetic Wave model displays the electric field of an electromagnetic wave. The simulation allows an arbitrarily polarized wave to be created. The magnitude of the electric field components and the relative phase between the components of the electric field can all be changed via sliders. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item. Ejs Electromagnetic Wave model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_ehu_waves_emwave.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for wave optics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Aguirregabiria, Juan

2008-08-20

78

Coherent hybrid electromagnetic field imaging  

DOEpatents

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.

Cooke, Bradly J. (Jemez Springs, NM); Guenther, David C. (Los Alamos, NM)

2008-08-26

79

Electromagnetic Radiations Emanating From A Quenched Superconducting Electromagnet  

Microsoft Academic Search

A qualitative discussion is presented on the subject of electromagnetic radiations emanating from an arc discharge which is the result of an accidentally quenched superconducting electromagnet. The discussion is based upon the assumption that the electromagnet is the B-field source of a sea-going vessel’s magnetohydrodynamic, MHD. power plant. Should such a vessel be one which operates subsurface, it then seems

S. A. Marshall; D. G. Yerg

1990-01-01

80

Plane Electromagnetic Wave in PEMC  

Microsoft Academic Search

Plane electromagnetic wave propagating in perfect electromagnetic conductor\\u000a(PEMC) is considered. Its wave number has no connection with the frequency. An\\u000ainterface is introduced between an ordinary isotropic medium and PEMC. The wave\\u000ain PEMC is matched to plane electromagnetic wave incident normally on the\\u000ainterface from the ordinary medium and reflected from it. Then the\\u000aplane-parallel slab made of

Bernard Jancewicz

2006-01-01

81

Torsion and the Electromagnetic Field  

Microsoft Academic Search

In the framework of the teleparallel equivalent of general relativity, we\\u000astudy the dynamics of a gravitationally coupled electromagnetic field. It is\\u000ashown that the electromagnetic field is able not only to couple to torsion, but\\u000aalso, through its energy-momentum tensor, to produce torsion. Furthermore, it\\u000ais shown that the coupling of the electromagnetic field with torsion preserves\\u000athe local

V. C. de Andrade; J. G. Pereira

1997-01-01

82

Phase characteristics of electromagnetic stirring  

SciTech Connect

Electromagnetic stirring is used at billet molds as well as at slab mold, to get high quality steel at continuous casting in steel making plant. In order to get the same electromagnetic force in each billet mold and thus the same quality, phase characteristics of electromagnetic stirring is investigated. From the calculation result, it is found that the relative phase at which the difference of the electromagnetic torque in each mold becomes the smallest is 0 or 240 deg. To apply the phase characteristics of the EMS to the quality control, the authors propose the dynamic phase control system by two inverters to get the high quality in the surface crack.

Fujisaki, Keisuke; Ueyama, Takatsugu [Nippon Steel Corp., Futtsu, Chiba (Japan). Process Research Lab.; Takahashi, Keiichi [Nippon Steel Corp., Muroran, Hokkaido (Japan). Muroran Works; Satoh, Shouji [Ohita Plant Design Corp. (Japan)

1997-09-01

83

Electromagnetic strong plasma turbulence  

SciTech Connect

The first large-scale simulations of continuously driven, two-dimensional electromagnetic strong plasma turbulence are performed, for electron thermal speeds 0.01c{<=}v{<=}0.57c, by integrating the Zakharov equations for coupled Langmuir and transverse (T) waves near the plasma frequency. Turbulence scalings and wave number spectra are calculated, a transition is found from a mix of trapped and free T eigenstates for v{>=}0.1c to just free eigenstates for v{<=}0.1c, and wave energy densities are observed to undergo slow quasiperiodic oscillations.

Melatos, A.; Jenet, F. A.; Robinson, P. A. [School of Physics, University of Melbourne, Parkville, VIC 3010 (Australia); Department of Physics and Astronomy, University of Texas at Brownsville, Brownsville, Texas 78520 (United States); School of Physics, University of Sydney, Sydney, NSW 2006 (Australia)

2007-02-15

84

Electromagnetically induced conical emission  

NASA Astrophysics Data System (ADS)

We describe theoretically a scheme for observing conical emission, a transverse nonlinear optical effect, in an atomic vapor with all excitation fields below the saturation level of the involved atomic transitions. The scheme relies on the giant Kerr nonlinearities possible under electromagnetically induced transparency to introduce a radially varying phase shift to a weak probe field by a weak signal field. The probe’s far-field diffraction pattern shows multiple concentric rings around the probe beam’s axis, characteristic of conical emission.

Becerra-Castro, E. M.; de Araujo, Luís E. E.

2010-12-01

85

Electromagnetic pump stator coil  

SciTech Connect

An electrical stator coil for an electromagnetic pump includes a continuous conductor strip having first and second terminals at opposite ends thereof and an intermediate section disposed therebetween. The strip is configured in first and second coil halves, with the first coil half including a plurality of windings extending from the first terminal to the intermediate section, and the second coil half including a plurality of windings extending from the second terminal to the intermediate section. The first and second coil halves are disposed coaxially, and the first and second terminals are disposed radially inwardly therefrom with the intermediate section being disposed radially outwardly therefrom. 9 figs.

Fanning, A.W.; Dahl, L.R.

1996-06-25

86

All electromagnetic form factors  

NASA Astrophysics Data System (ADS)

The electromagnetic form factors of spin-1/2 particles are known, but due to historical reasons only half of them are found in many textbooks. Given the importance of the general result, its model independence, its connection to discrete symmetries and their violations we made an effort to derive and present the general result based only on the knowledge of the Dirac equation. We discuss the phenomenology connected directly with the form factors, and spin precession in external fields including time-reversal violating terms. We apply the formalism to spin-flip synchrotron radiation and suggest pedagogical projects.

Nowakowski, M.; Paschos, E. A.; Rodríguez, J. M.

2005-07-01

87

Electromagnetics. Second edition  

SciTech Connect

This book presents an account of the fundamentals of electromagnetic theory, giving readers an intuitive grasp of the subject. Emphasis is on the physical basis of the subject, but without undue neglect of mathematics. It includes topics not usually found in the standard texts. It also includes new sections on hysteresis, coaxial waveguides, radiation pressure, scattering by bound charge, and reflection by the ionosphere. In addition it contains 20 new, fully worked examples that illustrate applications to some problems of practical complexity. Finally, it bridges the gap between highly mathematical works and the usual, less rigorous formulations of the subject, and thus provides an easily understandable introduction to the subject.

Laud, B.B.

1987-01-01

88

Electromagnetic transitions in hypernuclei  

SciTech Connect

The object of this review is to survey observations of electromagnetic transitions in hypernuclei and to point out contributions of these observations to an understanding of the effective two-body hyperon-nucleon forces in the nucleus. The discussion concentrates on lambda-hyperon nucleon potentials. Future plans for high resolution hypernuclear spectroscopy using Ge diode detectors is discussed, especially regarding the window of utility of such devices. Expected improvements in beam facilities are also reviewed. 9 refs., 4 figs., 1 tab. (DWL)

Chrien, R.E.

1986-01-01

89

The ALICE electromagnetic calorimeter  

NASA Astrophysics Data System (ADS)

ALICE is the general purpose experiment at the LHC dedicated to the study of heavy-ion collisions. The electromagnetic calorimeter (EMCal) is a late addition to the ALICE suite of detectors with first modules installed in ALICE this year. The EMCal is designed to trigger on high energy gamma-rays and jets, and to enhance the capabilities of ALICE for these measurements. The EMCal is a Pb/scintillator sampling shish-kebab type calorimeter. The EMCal construction, readout, and performance in beam tests at the CERN SPS and PS are described.

Awes, Terry C.; ALICE Collaboration

2010-05-01

90

Electromagnetic fuel injection valve  

SciTech Connect

An electromagnetic fuel injection valve is described comprising: (a) a housing made of a magnetic material; (b) a valve which opens and closes a fuel injection port that is hydraulically connected to the interior of the housing; (c) a moving core which drives the valve; (d) a fuel guide member which consists of a large diameter portion that is secured to the housing on the side opposite to the fuel injection port. A stationary core extends from the large diameter portion to protrude into the housing. A connection portion extends from the large diameter portion to protrude toward the outer side of the housing, and a penetration path extends from the protruding end of the stationary core to the protruding end of the connection portion; (e) an electromagnetic coil disposed in an annular space defined by the outer periphery of the stationary core and the inner periphery of the housing; (f) a tubular member which is disposed in the penetration path and which has openings at its both ends; and (g) sealing means which hydraulically seals the area between the outer periphery of the tubular member and the inner periphery of the penetration path at an end portion on the side of the fuel injection port of the tubular member.

Soma, M.; Atago, T.; Kido, T.

1986-12-02

91

Electromagnetic field litigation  

SciTech Connect

Scientific research has been unable to resolve satisfactorily the question whether potential biological effects, especially carcinogenicity, may be associated with exposure of humans to the electromagnetic fields (EMFs) from high-voltage transmission lines. It may be years before the necessary human, laboratory, and basic research produce the evidence needed for professional consensus on this environmental issue. But as the scientific debate and human exposure continue, public concern is being expressed in administrative and judicial proceedings. During the past decade, the public perceptions of risk from nonionizing radiation of electromagnetic fields has been a factor introduced in local, state, and federal hearings; administrative proceedings; and court litigation. The focus of this review is to highlight public concern by examining the pattern of litigation in which bioeffects were alleged to be associated with transmission (power) lines. In this regard, the courts have split widely on the probative value and admissibility of scientifically based testimony to support compensation claims. Condemnation cases involving appellate court review, selected trial-level cases, and the emergence of tort claims are described. The use of tort claims imposes a substantial burden of proof on the plaintiff to demonstrate a cause-effect relationship between EMF exposure and disease. Finally, risk communication and public policy are discussed.

Hamilton, C.B. (Univ. of Tennessee, Knoxville, TN (United States)); Easterly, C.E. (Oak Ridge National Lab., TN (United States). Health and Safety Research Division)

1993-01-01

92

Electromagnetic propulsion for spacecraft  

NASA Astrophysics Data System (ADS)

Three electromagnetic propulsion technologies, solid propellant pulsed plasma thrusters (PPT), magnetoplasmadynamic (MPD) thrusters, and pulsed inductive thrusters (PIT), were developed for application to auxiliary and primary spacecraft propulsion. Both the PPT and MPD thrusters were flown in space, though only PPT's were used on operational satellites. The performance of operational PPT's is quite poor, providing only approximately 8 percent efficiency at approximately 1000 s specific impulse. However, laboratory PPT's yielding 34 percent efficiency at 2000 s specific impulse were extensively tested, and peak performance levels of 53 percent efficiency at 5170 s specific impulse were demonstrated. MPD thrusters were flown as experiments on the Japanese MS-T4 spacecraft and the Space Shuttle and were qualified for a flight in 1994. The flight MPD thrusters were pulsed, with a peak performance of 22 percent efficiency at 2500 s specific impulse using ammonia propellant. Laboratory MPD thrusters were demonstrated with up to 70 percent efficiency and 700 s specific impulse using lithium propellant. While the PIT thruster has never been flown, recent performance measurements using ammonia and hydrazine propellants are extremely encouraging, reaching 50 percent efficiency for specific impulses between 4000 to 8000 s. The fundamental operating principles, performance measurements, and system level design for the three types of electromagnetic thrusters are reviewed, and available data on flight tests are discussed for the PPT and MPD thrusters.

Myers, Roger M.

1993-09-01

93

Electromagnetic direct implicit PIC simulation  

SciTech Connect

Interesting modelling of intense electron flow has been done with implicit particle-in-cell simulation codes. In this report, the direct implicit PIC simulation approach is applied to simulations that include full electromagnetic fields. The resulting algorithm offers advantages relative to moment implicit electromagnetic algorithms and may help in our quest for robust and simpler implicit codes.

Langdon, A.B.

1983-03-29

94

Electromagnetic forces in deformable continua  

Microsoft Academic Search

The main objective in the reported investigation is related to the determination of the interaction of the stress-strain field with the electromagnetic field in deformable bodies. The electromagnetic fields exert forces and torques on the induced sources in the matter and cause the latter to move and deform. Such interactions are considered for materials which can be polarized and magnetized,

Y.-H. Pao

1978-01-01

95

Electromagnetic Navigation during Flexible Bronchoscopy  

Microsoft Academic Search

Background: Flexible bronchoscopy is routinely utilized in the diagnosis and treatment of various lung diseases. Nondiagnostic bronchoscopy leads to more invasive interventions, such as transthoracic needle aspiration, mediastinoscopy or even thoracotomy. Electromagnetic navigation is a novel technology that facilitates approaching peripheral lung lesions, which are difficult to sample by conventional means. The navigation system involves creating an electromagnetic field around

Yehuda Schwarz; Atul C. Mehta; Armin Ernst; Felix Herth; Ahuva Engel; Doron Besser; Heinrich D. Becker

2003-01-01

96

Electromagnetic field effects in explosives  

Microsoft Academic Search

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: measurements of conductivity; enhancement of performance; and control of initiation and growth of reaction. Hayes...()^1 showed a strong correlation of peak electrical conductivity with carbon content of

Douglas Tasker

2009-01-01

97

Health hazards and electromagnetic fields  

Microsoft Academic Search

Biological rhythms, physical wellbeing and mental states are dependent on our electrical brainwave system interacting with the extremely weak electromagnetic fields generated by the Earth's telluric and Cosmic radiations. In a single generation, since the evolution of humankind over millions of years, we are exposed to a wide range of powerful, artificially generated electromagnetic radiation which adversely affects the subtle

T. Saunders

2003-01-01

98

The Electromagnetic Spectrum: Infrared Waves  

NSDL National Science Digital Library

This webpage, part of a NASA site on the electromagnetic spectrum, presents information on infrared light. An explanation of how objects emit infrared is provided, along with a diagram of the electromagnetic spectrum. The site contains a number of photos made with infrared light.

2007-06-24

99

Electromagnetic studies in geothermal regions  

Microsoft Academic Search

During the past 25 yr, nearly all available electromagnetic and geoelectric techniques have been tested for their usefulness in geothermal exploration and exploitation. Dipole-dipole profiling, audiomagnetotellurics and controlled source electromagnetic methods are examples of those which have proven to be rather efficient for geothermal exploration. From the hundreds of field surveys which have been performed in many geothermal regions of

A. Berktold

1983-01-01

100

Exploration of the Electromagnetic Environment  

ERIC Educational Resources Information Center

|The electromagnetic environment is composed of electric and magnetic fields which result from man-made and natural sources. An elementary experiment is described to explore the electromagnetic environment by measuring electric fields in the frequency range from approximately equal to 10 to 24 000 Hz. The equipment required to conduct the…

Fullekrug, M.

2009-01-01

101

Planarity Criteria in Electromagnetic Topology.  

National Technical Information Service (NTIS)

The principal tool of the electromagnetic topologist is the interaction sequence diagram (ISD), which is the dual graph of the electromagnetic topology (EMT) of a system. One of the problems of working with the ISD is its complex appearance, in part due t...

R. S. Noss

1984-01-01

102

Planarity criteria in electromagnetic topology  

Microsoft Academic Search

The principal tool of the electromagnetic topologist is the interaction sequence diagram (ISD), which is the dual graph of the electromagnetic topology (EMT) of a system. One of the problems of working with the ISD is its complex appearance, in part due to multiple crossings of edges. This report presents some necessary and sufficient conditions for a graph to be

R. S. Noss

1984-01-01

103

Nucleon Electromagnetic Form Factors  

SciTech Connect

There has been much activity in the measurement of the elastic electromagnetic proton and neutron form factors in the last decade, and the quality of the data has greatly improved by performing double polarization experiments, in comparison with previous unpolarized data. Here we review the experimental data base in view of the new results for the proton, and neutron, obtained at JLab, MAMI, and MIT-Bates. The rapid evolution of phenomenological models triggered by these high-precision experiments will be discussed, including the recent progress in the determination of the valence quark generalized parton distributions of the nucleon, as well as the steady rate of improvements made in the lattice QCD calculations.

Marc Vanderhaeghen; Charles Perdrisat; Vina Punjabi

2007-10-01

104

Causal electromagnetic interaction equations  

SciTech Connect

For the electromagnetic interaction of two particles the relativistic causal quantum mechanics equations are proposed. These equations are solved for the case when the second particle moves freely. The initial wave functions are supposed to be smooth and rapidly decreasing at the infinity. This condition is important for the convergence of the integrals similar to the integrals of quantum electrodynamics. We also consider the singular initial wave functions in the particular case when the second particle mass is equal to zero. The discrete energy spectrum of the first particle wave function is defined by the initial wave function of the free-moving second particle. Choosing the initial wave functions of the free-moving second particle it is possible to obtain a practically arbitrary discrete energy spectrum.

Zinoviev, Yury M. [Steklov Mathematical Institute, Gubkin Street 8, 119991, Moscow (Russian Federation)

2011-02-15

105

Computational electronics and electromagnetics  

SciTech Connect

The Computational Electronics and Electromagnetics thrust area at Lawrence Livermore National Laboratory serves as the focal point for engineering R&D activities for developing computer-based design, analysis, and tools for theory. Key representative applications include design of particle accelerator cells and beamline components; engineering analysis and design of high-power components, photonics, and optoelectronics circuit design; EMI susceptibility analysis; and antenna synthesis. The FY-96 technology-base effort focused code development on (1) accelerator design codes; (2) 3-D massively parallel, object-oriented time-domain EM codes; (3) material models; (4) coupling and application of engineering tools for analysis and design of high-power components; (5) 3-D spectral-domain CEM tools; and (6) enhancement of laser drilling codes. Joint efforts with the Power Conversion Technologies thrust area include development of antenna systems for compact, high-performance radar, in addition to novel, compact Marx generators. 18 refs., 25 figs., 1 tab.

Shang, C. C.

1997-02-01

106

Electromagnetic propulsion for spacecraft  

NASA Astrophysics Data System (ADS)

Three electromagnetic propulsion technologies, solid propellant pulsed plasma thrusters (PPT), magnetoplasmadynamic (MPD) thrusters, and pulsed inductive thrusters (PIT) have been developed for application to auxiliary and primary spacecraft propulsion. Both the PPT and MPD thrusters have been flown in space, though only PPTs have been used on operational satellites. The performance of operational PPTs is quite poor, providing only about 8 percent efficiency at about 1000 sec specific impulse. Laboratory PPTs yielding 34 percent efficiency at 5170 sec specific impulse have been demonstrated. Laboratory MPD thrusters have been demonstrated with up to 70 percent efficiency and 7000 sec specific impulse. Recent PIT performance measurements using ammonia and hydrazine propellants are extremely encouraging, reaching 50 percent efficiency for specific impulses between 4000 and 8000 sec.

Myers, Roger M.

1993-02-01

107

Electromagnetically induced self-imaging  

NASA Astrophysics Data System (ADS)

We study the self-imaging and image-transforming properties of a probe field in a cold atomic medium with electromagnetically induced transparency (EIT). Due to the similarities between the gradient-index medium and the inhomogeneous index distribution of an EIT medium under the conditions of a negative probe detuning and a Gaussian control field, we find based on analytical investigations that there exists a kind of electromagnetically induced self-imaging phenomenon in cold atomic media. Numerical simulations clearly show that electromagnetically induced self-imaging is observable and controllable.

Cheng, Jing; Han, Shensheng

2007-05-01

108

Electromagnetic Compatibility in Aerospace Vehicles.  

National Technical Information Service (NTIS)

Electromagnetic compatibility in aerospace vehicles which requires careful consideration because of the generally high packing density of electronic equipment aboard aircraft or spacecraft, the complex cable hardness and the required reliability margins. ...

O. B. M. Pietersen

1983-01-01

109

Biological effects of electromagnetic fields.  

National Technical Information Service (NTIS)

Natural background levels of atmospheric electric and geomagnetic field levels are extremely low. Over the past several decades, however, human beings and other life forms on this planet have been subjected to a dramatically changing electromagnetic milie...

L. E. Anderson

1991-01-01

110

Materials for electromagnetic interference shielding  

Microsoft Academic Search

Materials for the electromagnetic interference (EMI) shielding of electronics and radiation sources are reviewed, with emphasis\\u000a on composite materials and resilient EMI gasket materials, which shield mainly by reflection of the radiation at a high frequency.

D. D. L. Chung

2000-01-01

111

Surface Vibration Electromagnetic Speech Sensor.  

National Technical Information Service (NTIS)

Abstract-As researchers continue to improve speech in noisy II environments, more interest is being placed on sensors with modalities that can be fused with traditional acoustic sensors. The standard literature has shown that electromagnetic sensors can b...

E. F. Greneker I. Chuckpaiwong J. L. Geisheimer S. A. Billington

2002-01-01

112

Sommerfeld Integrals and Electromagnetic Fields.  

National Technical Information Service (NTIS)

The complete electromagnetic fields for both elementary electric and magnetic dipoles are listed for both horizontal and vertical orientations of the dipoles. All combinations of dipole and field point locations above or below the boundary between two con...

T. W. H. Caffey

1988-01-01

113

Self-dual electromagnetic fields  

NASA Astrophysics Data System (ADS)

We demonstrate the utility of self-dual fields in electrodynamics. Stable configurations of free electromagnetic fields can be represented as superpositions of standing waves, each possessing zero Poynting vector and zero orbital angular momentum. The standing waves are themselves superpositions of self-dual and anti-self-dual solutions. The idea of self-duality provides additional insights into the geometrical and spectral properties of stable electromagnetic configurations, such as those responsible for the formation of ball lightning.

Chubykalo, Andrew E.; Espinoza, Augusto; Kosyakov, B. P.

2010-08-01

114

Electromagnetic Effects in SDF Explosions  

Microsoft Academic Search

The notion of high ion and electron concentrations in the detonation of aluminized explosive mixtures has aroused some interest in electro-magnetic effects that the SDF charges might generate when detonated. Motivated by this interest we have started to investigate whether significant electro-magnetic effects show up in our small-scale experiments. However, the design of instrumentation for this purpose is far from

H Reichenbach; P Neuwald; A L Kuhl

2010-01-01

115

Electromagnetic holographic imaging of bioimpedance  

NASA Astrophysics Data System (ADS)

The electromagnetic bioimpedance method has successfully measured the very subtle conductivity changes associated with brain edema and prostate tumor. This method provides noninvasive measurements using non-ionizing magnetic fields applied with a small coil that avoids the use of contact electrodes. This paper introduces results from combining a holographic signal processing algorithm and a low power coil system that helps provide the 3D image of impedance contrast that should make the noninvasive electromagnetic bioimpedance method useful in health care.

Smith, Dexter G.; Ko, Harvey W.; Lee, Benjamin R.; Partin, Alan W.

1998-05-01

116

The Nature of Electromagnetic Radiation  

NSDL National Science Digital Library

This web site is a reference page on electromagnetic radiation. It discusses the spectrum of light and both the wave and quantum nature of radiation. Also included are descriptions of the physics and applications of the different frequency bands, from gamma rays through radio waves, plus links to interactive Java simulations on the topic. See Related Materials on this page for a simpler student tutorial by the same authors on the topic of electromagnetic radiation.

Davidson, Michael; Abramowitz, Mortimer; Fellers, Thomas J.

2008-08-21

117

Time Reversal of Electromagnetic Waves  

Microsoft Academic Search

We report the first experimental demonstration of time-reversal focusing with electromagnetic waves. An antenna transmits a 1-mus electromagnetic pulse at a central frequency of 2.45GHz in a high-Q cavity. Another antenna records the strongly reverberated signal. The time-reversed wave is built and transmitted back by the same antenna acting now as a time-reversal mirror. The wave is found to converge

G. Lerosey; J. de Rosny; A. Tourin; A. Derode; G. Montaldo; M. Fink

2004-01-01

118

Electromagnetic methods in applied geophysics  

NASA Astrophysics Data System (ADS)

Review of promising new research developments dealing with electromagnetic methods in applied geophysics. Slow, steady progress of numerical modeling is seen in traditional low-frequency CW technology. Cryogenic coil systems are viewed as the major development in this area. In the newer area of transient applications, the most impressive results are coming from the use of seismic processing with earth-penetrating radar and the rapid development of transient electromagnetic equipment, theory, and experience.

Vozoff, K.

1980-09-01

119

Polarimetry of electromagnetic materials  

NASA Astrophysics Data System (ADS)

The goal of the polarimetry of electromagnetic solids is the thorough determinations of not only the linear and circular birefringences (LB an CB) but also the linear and circular dichroisms (LD and CD). Needless to say, measurements of circular phenomena are exceedingly more difficult than those of linear ones. For instance, the long period of 170 years elapsed from the discovery of CB by Arago in 1811 until the development of high accuracy universal polarimeter (HAUP) by Kobayashi in 1983, when the first perfect measurements of CB of solids became possible. Subsequent to the appearance of the HAUP method, attempts of extending HAUP theory to be applicable to CD measurements were followed by Moxon and Renshaw, and Dijkstra, Kremers, and Meekes by using Jones matrix calculus. However, their measurements to NiSO4 multiplied by 6H2O were not fully satisfactory. We completed afresh the theory of the extended HAUP and measured successfully LD of a high temperature superconductor Bi2Sr2CaCu2O8. An important fact was clarified; the extended HAUP theory indicates that CD can be obtained exclusively through accurate measurements of (theta) 0, a characteristic angle introduced in the original HAUP method. It means that there would be no ways for measuring CD of solids except for the HAUP method. Preliminary results of applying our theory to silver thiogallate are shown finally.

Asahi, Toru; Osaka, Tetsuya; Kobayashi, Jinzo

2001-07-01

120

SOLAR NANTENNA ELECTROMAGNETIC COLLECTORS  

SciTech Connect

This research explores a new efficient approach for producing electricity from the abundant energy of the sun. A nanoantenna electromagnetic collector (NEC) has been designed, prototyped, and tested. Proof of concept has been validated. The device targets mid-infrared wavelengths where conventional photovoltaic (PV) solar cells do not respond but is abundant in solar energy. The initial concept of designing NEC antennas was based on scaling of radio frequency antenna theory. This approach has proven unsuccessful by many due to not fully understanding and accounting for the optical behavior of materials in the THz region. Also until recent years the nanofabrication methods were not available to fabricate the optical antenna elements. We have addressed and overcome both technology barriers. Several factors were critical in successful implementation of NEC including: 1) frequency-dependent modeling of antenna elements, 2) selection of materials with proper THz properties and 3) novel manufacturing methods that enable economical large-scale manufacturing. The work represents an important step toward the ultimate realization of a low-cost device that will collect as well as convert this radiation into electricity, which will lead to a wide spectrum, high conversion efficiency, and low cost solution to complement conventional PVs.

Steven D. Novack; Dale K. Kotter; Dennis Slafer; Patrick Pinhero

2008-08-01

121

Information Security due to Electromagnetic Environments  

NASA Astrophysics Data System (ADS)

Generally, active electronic devices emit slightly unintentional electromagnetic noise. From long ago, electromagnetic emission levels have been regulated from the aspect of electromagnetic compatibility (EMC). Also, it has been known the electromagnetic emissions have been generated from the ON/OFF of signals in the device. Recently, it becomes a topic of conversation on the information security that the ON/OFF on a desired signal in the device can be reproduced or guessed by receiving the electromagnetic emission. For an example, a display image on a personal computer (PC) can be reconstructed by receiving and analyzing the electromagnetic emission. In sum, this fact makes known information leakage due to electromagnetic emission. “TEMPEST" that has been known as a code name originated in the U. S. Department of Defense is to prevent the information leakage caused by electromagnetic emissions. This paper reports the brief summary of the information security due to electromagnetic emissions from information technology equipments.

Sekiguchi, Hidenori; Seto, Shinji

122

Electromagnetic potentials without gauge transformations  

NASA Astrophysics Data System (ADS)

In this paper, we show that the use of the Helmholtz theorem enables the derivation of uniquely determined electromagnetic potentials without the necessity of using gauge transformation. We show that the electromagnetic field comprises two components, one of which is characterized by instantaneous action at a distance, whereas the other propagates in retarded form with the velocity of light. In our attempt to show the superiority of the new proposed method to the standard one, we argue that the action-at-a-distance components cannot be considered as a drawback of our method, because the recommended procedure for eliminating the action at a distance in the Coulomb gauge leads to theoretical subtleties that allow us to say that the needed gauge transformation is not guaranteed. One of the theoretical consequences of this new definition is that, in addition to the electric E and magnetic B fields, the electromagnetic potentials are real physical quantities. We show that this property of the electromagnetic potentials in quantum mechanics is also a property of the electromagnetic potentials in classical electrodynamics.

Chubykalo, A.; Espinoza, A.; Alvarado Flores, R.

2011-07-01

123

High performance electromagnetic simulation tools  

NASA Astrophysics Data System (ADS)

Army Research Office Grant #DAAH04-93-G-0453 has supported the purchase of 24 additional compute nodes that were installed in the Intel iPsC/860 hypercube at the Univesity Of Kentucky (UK), rendering a 32-node multiprocessor. This facility has allowed the investigators to explore and extend the boundaries of electromagnetic simulation for important areas of defense concerns including microwave monolithic integrated circuit (MMIC) design/analysis and electromagnetic materials research and development. The iPSC/860 has also provided an ideal platform for MMIC circuit simulations. A number of parallel methods based on direct time-domain solutions of Maxwell's equations have been developed on the iPSC/860, including a parallel finite-difference time-domain (FDTD) algorithm, and a parallel planar generalized Yee-algorithm (PGY). The iPSC/860 has also provided an ideal platform on which to develop a 'virtual laboratory' to numerically analyze, scientifically study and develop new types of materials with beneficial electromagnetic properties. These materials simulations are capable of assembling hundreds of microscopic inclusions from which an electromagnetic full-wave solution will be obtained in toto. This powerful simulation tool has enabled research of the full-wave analysis of complex multicomponent MMIC devices and the electromagnetic properties of many types of materials to be performed numerically rather than strictly in the laboratory.

Gedney, Stephen D.; Whites, Keith W.

1994-10-01

124

Electromagnetic diode based on nonlinear electromagnetically induced transparency in metamaterials  

NASA Astrophysics Data System (ADS)

We propose a scheme for subwavelength electromagnetic diode by employing the nonreciprocal electromagnetically induced transparency (EIT) in metamaterials. One-way response, with 17.36 dB transmission contrast and -4.4 dBm operating power, is conceptually demonstrated in a microwave waveguide system with asymmetric absorption and a varactor as the nonlinear medium inclusion. Such low-threshold and high-contrast transmission diode action comes from the EIT mechanism, which possesses narrower and sharper features than the Lorentz resonance. This mechanism will be useful for all-optical signal processing with advanced materials.

Sun, Yong; Tong, Yuan-wei; Xue, Chun-hua; Ding, Ya-qiong; Li, Yun-hui; Jiang, Haitao; Chen, Hong

2013-08-01

125

Electromagnetic fields and public health.  

PubMed Central

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.

Aldrich, T E; Easterly, C E

1987-01-01

126

Gauge invariant fractional electromagnetic fields  

NASA Astrophysics Data System (ADS)

Fractional derivatives and integrations of non-integers orders was introduced more than three centuries ago but only recently gained more attention due to its application on nonlocal phenomenas. In this context, several formulations of fractional electromagnetic fields was proposed, but all these theories suffer from the absence of an effective fractional vector calculus, and in general are non-causal or spatially asymmetric. In order to deal with these difficulties, we propose a spatially symmetric and causal gauge invariant fractional electromagnetic field from a Lagrangian formulation. From our fractional Maxwell's fields arose a definition for the fractional gradient, divergent and curl operators.

Lazo, Matheus Jatkoske

2011-09-01

127

Introduction to The Electromagnetic Spectrum  

NSDL National Science Digital Library

This NASA-created web site introduces electromagnetic waves and their behaviors to secondary learners. Each region of the spectrum is described, illustrated, and accompanied by video clips. Within each section, the authors explore the relationship between wavelength and wave type and provide information about how scientists detect the various waves and collect images of their emissions. Don't miss the link to NASA's Tour of the Electromagnetic Spectrum, a free set of 24 posters, which can be viewed online or printed for the classroom. This tutorial is part of NASA's Mission: Science website.

2009-10-05

128

Methodology for Selecting an Electromagnetic Gun System.  

National Technical Information Service (NTIS)

This thesis proposes a methodology for selecting an electromagnetic launcher (EML) based upon mission requirements and available technology. The intent of the study is twofold. First, it reviews electromagnetic launcher applications, the principles of ele...

K. E. Reinhard

1992-01-01

129

Numerical Analysis of Electromagnetic Bandgap Structures.  

National Technical Information Service (NTIS)

Electromagnetic bandgap (EBG) structures and negative index of refraction (NIR) meta-materials are periodic dielectric or metallic material structures that allow greater control over electromagnetic waves than has previously been possible. Man-made versio...

R. S. Schechter S. T. Chun

2007-01-01

130

Electromagnetic Radiation System (EMRS) for Susceptibility Testing.  

National Technical Information Service (NTIS)

The function of the Electromagnetic Radiation System (EMRS) is to generate electromagnetic energy so as to produce a constant field strength that can be automatically scanned as a function of frequency. The design objective is to cover the frequency range...

J. M. VanArsdale

1978-01-01

131

Electromagnetic Radiation System (EMRS) for Susceptibility Testing.  

National Technical Information Service (NTIS)

The function of the Electromagnetic Radiation System (EMRS) is to generate electromagnetic energy so as to produce a constant field strength that can be automatically scanned as a function of frequency. The design objective is to cover the frequency range...

E. S. Iskra

1976-01-01

132

Electromagnetic Radiation System (EMRS) for Susceptibility Testing.  

National Technical Information Service (NTIS)

The function of the Electromagnetic Radiation System (EMRS) is to generate electromagnetic energy so as to produce a constant field strength that can be automatically scanned as a function of frequency. The design objective is to cover the frequency range...

E. S. Iskra

1977-01-01

133

Electromagnetic Radiation System (EMRS) for Susceptibility Testing.  

National Technical Information Service (NTIS)

The Electromagnetic Radiation System (EMRS) is designed to generate electromagnetic energy to produce a constant field strength while scanned automatically in frequency. Design objective was 200 volts per meter from 30 Hz to 40 GHz. This report describes ...

J. V. Arsdale

1981-01-01

134

Electromagnetic Radiation System (EMRS) for Susceptibility Testing.  

National Technical Information Service (NTIS)

The function of the Electromagnetic Radiation System (EMRS) is to generate electromagnetic energy to produce a constant field strength that can be automatically scanned as a function of frequency. The design objective is to cover the frequency range of 30...

M. V. Stone

1979-01-01

135

Electromagnetic Compatibility of Nuclear Power Plants.  

National Technical Information Service (NTIS)

Lately, there has been a mounting concern about the electromagnetic compatibility of nuclear-power-plant systems mainly because of the effects due to the nuclear electromagnetic pulse, and also because of the introduction of more-sophisticated and, theref...

H. S. Cabayan

1983-01-01

136

Galium Electromagnetic (GEM) Thruster Concept and Design.  

National Technical Information Service (NTIS)

We describe the design of a new type of two-stage pulsed electromagnetic accelerator, the gallium electromagnetic (GEM) thruster. A schematic illustration of the GEM thruster concept is given. In this concept, liquid gallium propellant is pumped into the ...

K. A. Polzin T. E. Markusic

2005-01-01

137

Visible Light and the Electromagnetic Spectrum  

NSDL National Science Digital Library

During this lesson, the electromagnetic spectrum is explained and students learn that visible light makes up only a portion of this wide spectrum. Students also learn that engineers use electromagnetic waves for many different applications.

Integrated Teaching And Learning Program

138

Electromagnetic coupling on complex systems - Topological approach  

Microsoft Academic Search

The principles of electromagnetic topology, developed by Baum, are reviewed. The method involves breaking a complex electromagnetic problem down into several small ones that are easier to solve. An example is used to illustrate the advantages of the approach.

J. P. Parmantier; G. Labaume; J. C. Alliot; P. Degauque

1990-01-01

139

3D Electromagnetic Field Analysis for Mixing Suspension Electromagnet Used by Maglev Train  

Microsoft Academic Search

A maglev train is supported by electromagnetic force between suspension electromagnet and track and is driven by linear motor. The suspension electromagnet is an important part of a maglev train. Its operating characteristic has a direct bearing on technology-economy performance and run safety of the whole train. The paper advances a new electromagnet structure mixing permanent magnet with electric excitation

Liu Shaoke; Guo Zhongjun; Chen Guirong

2010-01-01

140

Electromagnetic design considerations for fast acting controllers  

SciTech Connect

Electromagnetic design considerations for fast acting controllers in a power system is introduced and defined. A distinction is made in relation to the more commonly understood system control design necessary for damping electromechanical oscillations using stability programs and eigenanalysis. Electromagnetic eigenanalysis tools have limited availability and are consequently rarely used. Electromagnetic transients programs (emtp) on the other hand are widely used and a procedure for undertaking electromagnetic control design of fast acting controllers in a power system using emtp is presented.

Woodford, D.A. [Manitoba HVDC Research Centre, Winnipeg, Manitoba (Canada)

1996-07-01

141

The electromagnetic spectrum : waves of energy  

NSDL National Science Digital Library

In this lesson, students will (1) understand that the sun energy is transferred to Earth by electromagnetic waves, which are transverse waves, (2) understand that there are eight main types of electromagnetic waves, classified on the electromagnetic spectrum according to their wavelengths, and (3) understand how each of the types of electromagnetic radiation is used or found in our everyday lives. This would be a suitable activity for small groups.

Coulson, Tracy; Kennedy, Karen

2002-01-01

142

The theory of the electromagnetic field  

Microsoft Academic Search

Aspects related to the concepts of charge and current are considered along with the effect of the electromagnetic field on general charge distributions, the electrical field produced by static charges, the magnetic induction field produced by steady currents, the electromagnetic field produced by time-dependent charge distributions, plane electromagnetic waves in vacuum, problems of potential theory, and time-dependent fields in the

D. M. Cook

1975-01-01

143

Speed of the Electromagnetic Gravitational Wave  

Microsoft Academic Search

With inter-nuclear, gravitational, electromagnetic coupling, and gravitational external body coupling, the electromagnetic waves launched at nucleon level must travel at a speed greater than light speed. This speed is 4.1 x 10 to the 10 meters per second, which is 137 times the normal speed of light. Matter has to be mostly transparent to the gravitational electromagnetic waves emitted; and

Ronald R. Kotas

2000-01-01

144

Smart electromagnetic structures: The neural antenna  

Microsoft Academic Search

Smart electromagnetic structures (SEMS) are defined as structures capable of interacting with their surrounding electromagnetic fields and either influencing the field or sensing and adapting to its presence. A structure is smart when it integrates sensing elements (e.g., antennas), processing elements (neural networks) and control elements (diodes) autonomously. SEMS provide an adaptive electromagnetic (EM) environment for the structure on which

Michael H. Thursby

1993-01-01

145

Electromagnetism radialization protection in interior design  

Microsoft Academic Search

With the increasing electromagnetic radiation of household appliances, the impacts of electromagnetic radiation on the people are larger than before. This paper aims to solve the problems which reducing the electromagnetic radiation at maximum extent by displaying furnitures or plants and using materials in the interior house design. There is big distinction when people displace the household appliances on different

Zhihao Zou; Weiping Hu; Yanyan Wang

2008-01-01

146

Resource Letter EM-1: Electromagnetic Momentum  

NASA Astrophysics Data System (ADS)

This Resource Letter surveys the literature on momentum in electromagnetic fields, including the general theory, the relation between electromagnetic momentum and vector potential, ``hidden'' momentum, the 4/3 problem for electromagnetic mass, and the Abraham-Minkowski controversy regarding the field momentum in polarizable and magnetizable media.

Griffiths, David J.

2012-01-01

147

Transient electromagnetic effects on networks using CRIPTE  

Microsoft Academic Search

A novel simulation approach to electromagnetic computations involving large, complex systems is described for studying the effects of high power radio-frequency pulses. The approach uses the electromagnetic topology method. The adoption of the multi-conductor transmission analysis gives the results that are in good agreement with other solution methods. The electromagnetic topology method has been extended to the analysis of buried

Naz E. Islam; S. Joe Yakura; J. P. Parmantier

2002-01-01

148

An overview of the electromagnetic topology  

Microsoft Academic Search

A general description of the electromagnetic topology method is presented with emphasis on the topological diagram and interaction graph. Quantitative treatment of electromagnetic interactions is considered, and for a general case, a model physically representing the propagation channels of electromagnetic signals and their scattering in topological volumes is derived. A multiconductor transmission line network is analyzed, and simplifications and approximations

J. P. Parmantier; X. Ferrieres; J. P. Aparicio; J. C. Alliot

1991-01-01

149

Electromagnetic aircraft launch system-EMALS  

Microsoft Academic Search

With the proliferation of electromagnetic launch systems presently being designed, built, or studied, there appears to be no limit to their application. One of the intriguing applications is electromagnetically catapulting aircraft from the deck of an aircraft carrier. The US Navy had foreseen the substantial capabilities of an electromagnetic catapult in the 1940s and built a prototype. However, it was

Michael R. Doyle; Douglas J. Samuel; Thomas Conway; Robert R. Klimowski

1995-01-01

150

Integrating electromagnetic launchers on ships  

Microsoft Academic Search

Naval combatant ships of the future will have high power electrically powered weapons systems, including electromagnetic launchers. Integrating high power electric gun systems into ships poses unique issues that ship designers have not faced before. These issues must be identified and addressed early in the conceptual design stage for successful development and integration of high power electric gun systems into

Antonios Challita; John Barber; John Ykema; Cliff Allen

2004-01-01

151

The courts and electromagnetic fields  

SciTech Connect

This article examines the recent development in eminent domain cases involving power transmission line rights of way, the issue of fear of the mythical buyer. The author feels that the fear of electrocution or of the possible cancer-inducing effects of electromagnetic fields is greatly influencing court decisions in these cases. The results could be more expensive rights of way acquisition by utilities.

Freeman, M. (Univ. of Pennsylvania, Philadelphia (United States))

1990-07-19

152

Chopper-Operated Electromagnetic Flowmeter  

Microsoft Academic Search

The problem of design of a square-wave electromagnetic flowmeter may be simplified by the use of a mechanical chopper as the gating device. Such an instrument has been assembled using commercial components costing less than $1000. A commercial 400-cycle chopper amplifier, Offner model 190, was modified to perform the sampling. Carrier signal was provided by Tektronix 162 and 161 generators.

Francis L. Abel

1959-01-01

153

Ferro tale: electromagnetic animation interface  

Microsoft Academic Search

In this video we demonstrate the idea and the prototype of an electromagnetic animation interface, ferro tale. Ferromagnetic particles, such as iron filings, have very fascinating characteristics. Therefore they are widely used in art, education and as toys. Besides their potential to enable visual and tactile feedback and to be used as a medium for high resolution tangible input, peoples

Nan Zhao; Xiang Cao; Jaturont Jamigranont

2012-01-01

154

Electromagnetic Levitation of a Disc  

ERIC Educational Resources Information Center

This paper presents a teaching experiment that explores the levitation of a disc of ferromagnetic material in the presence of the magnetic field produced by a single electromagnet. In comparison to the classical experiment of the levitation of a sphere, the main advantage of the proposed laboratory bench is that the uniform magnetic field…

Valle, R.; Neves, F.; de Andrade, R., Jr.; Stephan, R. M.

2012-01-01

155

Transient electromagnetic interference in substations  

Microsoft Academic Search

Electromagnetic interference levels on sensitive electronic equipment are quantified experimentally and theoretically in air and gas insulated substations of different voltages. Measurement techniques for recording interference voltages and currents and electric and magnetic fields are reviewed and actual interference data are summarized. Conducted and radiated interference coupling mechanisms and levels in substation control wiring are described using both measurement results

C. M. Wiggins; D. E. Thomas; F. S. Nickel; T. M. Salas; S. E. Wright

1994-01-01

156

Electromagnetic interference from wind turbines  

Microsoft Academic Search

Summary form only given. During the late nineteen seventies and eighties the University of Michigan Radiation Laboratory, under sponsorship from the US Department of Energy, studied theoretically and experimentally the effects of wind turbines (WTs) on the performance of various electromagnetic systems. The article summarizes selected portions of the fundamental work carried out and techniques developed under the program which

D. L. Sengupta

1999-01-01

157

Finite formulation of electromagnetic field  

Microsoft Academic Search

We show that the equations of electromagnetism can be directly obtained in a finite form, i.e., discrete, thus avoiding the traditional discretization methods of Maxwell's differential equations. The finite formulation can be used with unstructured meshes in two and three dimensions and easily permits to obtain fourth-order convergence

Enzo Tonti; Piazzale Europa

2002-01-01

158

Finite Element Methods for Electromagnetics.  

National Technical Information Service (NTIS)

In the present report, an overview is given over a number of options for formulating finite-element methods for the computation of electromagnetic fields directly in terms of the electric and/or magnetic field components that are required. A number of exi...

I. E. Lager G. Mur

2000-01-01

159

Technology-based electromagnetic education  

Microsoft Academic Search

In this paper, we briefly review the various roles of technology in stimulating interest and deepening understanding of abstract and highly mathematical subjects such as electromagnetics (EM). The general advantages of using technology in offering Web-based courses and professional training are described and examples of the ongoing activities in this area are summarized. Focus, however, is placed on the development

Magdy F. Iskander

2002-01-01

160

Cell Effects of Electromagnetic Radiation  

Microsoft Academic Search

The effects of electromagnetic radiation on cells and cell organelles are reviewed. The original results of studies of the influence of monochrome and impulse radiation on human cells are presented. The heterochromatin granule quantity was investigated as a parameter indicating the state of human cell. It was shown that heterochromatin granule quantity and cell membrane permeability increases under the influence

Y. G. Shckorbatov; N. N. Kolchigin; V. A. Grabina; V. N. Pasiuga; O. V. Kazansky

2006-01-01

161

Electromagnetic radiation and biological effects  

Microsoft Academic Search

A review on biological effects of low power radiation on humans and animals is presented. Effects of electromagnetic coupling between the cellular\\/PCS phone antenna and the human head model have been described. Theoretical plots of the near-field patterns are shown for the human brain. An Independent Expert Group on Mobile Phones (IEGMP) of the UK discourages the use of mobile

A. Kumar

2001-01-01

162

A new electromagnetic valve actuator  

Microsoft Academic Search

In conventional internal combustion (IC) engines, en- gine valve displacements are fixed relative to crankshaft position. If these valves are actuated as a variable function of crankshaft an- gle, significant improvements in fuel economy can be achieved. Ex- isting electromagnetically actuated variable-valve-timing (VVT) systems characteristically use springs to provide the large iner- tial power to move the engine valves. However,

W. S. Changt; T. A. Parlikart; M. D. Seemant; D. J. Perreaultt; J. G. Kassakian; T. A. Keirnl

2002-01-01

163

Electromagnetic Levitation of a Disc  

ERIC Educational Resources Information Center

|This paper presents a teaching experiment that explores the levitation of a disc of ferromagnetic material in the presence of the magnetic field produced by a single electromagnet. In comparison to the classical experiment of the levitation of a sphere, the main advantage of the proposed laboratory bench is that the uniform magnetic field…

Valle, R.; Neves, F.; de Andrade, R., Jr.; Stephan, R. M.

2012-01-01

164

Electromagnetic focusing in biological tissues  

Microsoft Academic Search

In this work we assess the feasibility of focused electromagnetic ablation of breast cancer. In our approach we consider two degrees of freedom, namely the bolus permittivity and the operational frequency. The electric fi elds in at wo- dimensional configuration are computed per source using the iterative conjugate gradient method. The fields are subsequently focused in two lesions. The focusing

W. M. Brink; I. E. Lager; B. J. Kooij

2011-01-01

165

Electromagnetic Interactions and Hadronic Structure  

NASA Astrophysics Data System (ADS)

1. Quark models of hadrons and issues in quark dynamics; 2. Elastic form factors; 3. Electromagnetic excitations of nucleon resonances; 4. Meson radiative decays; 5. Intermediate-energy photoproduction; 6. Chiral perturbation theory; 7. Spin structure functions; 8. Diffraction and colour dipoles; 9. Generalized parton distributions; 10. Quark-hadron duality; 11. Colour transparency; Index.

Close, Frank; Donnachie, Sandy; Shaw, Graham

2007-05-01

166

Electromagnetic Interactions and Hadronic Structure  

NASA Astrophysics Data System (ADS)

1. Quark models of hadrons and issues in quark dynamics; 2. Elastic form factors; 3. Electromagnetic excitations of nucleon resonances; 4. Meson radiative decays; 5. Intermediate-energy photoproduction; 6. Chiral perturbation theory; 7. Spin structure functions; 8. Diffraction and colour dipoles; 9. Generalized parton distributions; 10. Quark-hadron duality; 11. Colour transparency; Index.

Close, Frank; Donnachie, Sandy; Shaw, Graham

2009-07-01

167

Electromagnetic backscatter predictions using XPATCH  

Microsoft Academic Search

The ability to accurately identify objects solely from their electromagnetic backscatter is of continuing interest. In order for object identification to be practical, a comprehensive catalog of signatures must be generated. The prediction code XPATCH is one tool capable of generating such a catalog. It is a high frequency polarimetric code based on the shooting and bouncing ray (SBR) method,

R. O. Jernejcic; R. F. Schindel

1994-01-01

168

Electromagnetic topology - Junction characterization methods  

Microsoft Academic Search

The electrical characterization of topological network junctions using a formalism in accordance with electromagnetic topology is discussed. It is shown how the characteristic impedance of the network in which the junction is located can be chosen to treat several physical cable connection and termination configurations. Junctions which represent the separation of a conductor into other conductors are used as an

J. P. Parmantier; G. Labaume; J. C. Alliot; P. Degauque

1990-01-01

169

Electromagnetic configurations of rail guns  

Microsoft Academic Search

Some problems associated with the electromagnetic acceleration of macrobodies in a rail gun are examined. An approach to the design of rail gun configurations is proposed, and some basic rail gun schemes are synthesized. The alternative rail gun schemes are compared in terms of electrode potential and stability of the electrode gap with respect to parasitic current shunting. The effect

O. V. Fat'yanov; V. E. Ostashev; A. N. Lopyrev; A. V. Ul'Yanov

1993-01-01

170

Electromagnetic fields near rail guns  

Microsoft Academic Search

The field in the neighborhood of an electromagnetic railgun is computed for the case of constant current. The analysis centers on the Westinghouse EMACK launcher in which two rails of 5-m length carry a peak current of 2.1 MA, while a peak power of over 10 GW is delivered to the rails. Expressions are derived for electric field strength and

William G. Soper

1989-01-01

171

Electromagnetically actuated ball valve micropumps  

Microsoft Academic Search

We present two types of oscillating diaphragm micropumps configured with passive ball valves and using electromagnetic actuation. One type is made out of poly(methyl methacrylate) (PMMA), while the other one is made out of borosilicate glass. Both were produced using the powder blasting microfabrication method. The pumping resonant frequency was measured to be within the range of 20-30 Hz for

Christophe Yamahata; Frédéric Lacharme; Jan Matter; Silvan Schnydrig; Yves Burri; Martin A. M. Gijs

2005-01-01

172

Computational design for electromagnetic simulations  

NASA Astrophysics Data System (ADS)

An automatic computational procedure has been developed to efficiently and accurately design the shape of complicated electromagnetic objects. These electromagnetic objects can be simulated for operation at high frequencies (˜10 GHz), and can be comprised of dissimilar materials. The automated design procedure consists of linking together an original electromagnetic field simulation tool, an original adjoint routine for obtaining sensitivity derivatives, and an original grid-smoothing tool with an existing optimization package. The electromagnetic field simulation software employs a temporally and spatially higher-order accurate Streamline Upwind/Petrov-Galerkin finite-element method that numerically solves Maxwell's equations in the time domain using implicit time stepping. The software for computing sensitivity derivatives employs a reverse-mode time-accurate discrete adjoint methodology that is formulated to automatically maintain consistency with the electromagnetic field simulation software. Grid smoothing is achieved using a spatially higher-order accurate Galerkin finite-element method that generates a numerical solution to the linear elastic equations. All computational solutions to the linear systems present in each software tool are obtained using the Generalized Minimum Residual algorithm with block diagonal preconditioning. Each software tool is implemented using a parallel processing paradigm and is therefore capable of being executed on a distributed memory supercomputer. The order of accuracy of the electromagnetic field simulation software has been determined by using comparisons with exact solutions. The field software's results were compared to the exact solution of a rectangular resonant cavity. In all cases, the order properties of the field software exceed theoretical expectations when linear, quadratic, and cubic tetrahedral elements are employed to discretize the field. To demonstrate the consistency of the adjoint-based sensitivity derivates with those obtained directly from the field solver, derivatives have been extracted from the field software using a complex variable technique. The sensitivity derivatives from the reverse-mode time-accurate discrete adjoint method were then compared and demonstrated to agree to at least seven decimal places. As a demonstration of the assembled technologies, the optimization procedure successfully and efficiently modified the shape of two electromagnetic objects to reduce a specified cost function. A dielectric cube, under the influence of a propagating plane wave, was repositioned within a larger free space volume so that the field variables on the surface of the cube match desired values at a specified time. A similar demonstration case has also been conducted to modify the shape of a dielectric ellipsoid, under the same conditions as the cube.

Glasby, Ryan Steven

173

Electromagnetic environmental criteria for US Army missile systems: EMC (electromagnetic compatibility), EMR (electromagnetic radiation), EMI (electromagnetic interference), EMP (electromagnetic pulse), ESD (electrostatic discharge), and lightning. Final report for period ending October 1986  

Microsoft Academic Search

This report presents the design and test requirements in developing an electromagnetic compatibility missile system. Environmental levels are presented for electromagnetic radiation hazards, electromagnetic radiation operational electrostatic discharge, lightning, and electromagnetic pulse (nuclear). Testing techniques and facility capabilities are presented for research and development testing of missile systems.

M. Kilpatrick; C. D. Ponds

1987-01-01

174

Electromagnetic transduction of ultrasonic waves  

NASA Astrophysics Data System (ADS)

Excitation and detection of ultrasonic vibrations without physical contact has proven to be of great commercial value. First used to excite the resonant vibration of bar shaped laboratory specimens in the 1930's, it was Bruce Thompson's contributions in 1973-5 that launched their practical application to a wide range of difficult NDE problems. As a fresh PhD, he championed the use of mathematical models for the electromagnetic transduction process in order to guide the design and construction of practical transducers. His early papers presented both theoretical and experimental results that exposed the wide range of wave types that could be generated along with the environmental conditions that could be overcome. Several laboratories around the world established research programs to apply the electromagnetic transducer (EMAT) to specific NDE problems. This paper will summarize those applications made by the authors.

Passarelli, Frank; Alers, George; Alers, Ron

2012-05-01

175

Electromagnetic moments of quasistable particle  

SciTech Connect

We deal with the problem of assigning electromagnetic moments to a quasistable particle (i.e., a particle with mass located at the particle's decay threshold). In this case, an application of a small external electromagnetic field changes the energy in a nonanalytic way, which makes it difficult to assign definitive moments. On the example of a spin-1/2 field with mass M{sub *} interacting with two fields of masses M and m, we show how a conventionally defined magnetic dipole moment diverges at M{sub *}=M+m. We then show that the conventional definition makes sense only when the values of the applied magnetic field B satisfy |eB|/2M{sub *}<<|M{sub *}-M-m|. We discuss implications of these results to existing studies in electroweak theory, chiral effective-field theory, and lattice QCD.

Ledwig, Tim; Pascalutsa, Vladimir; Vanderhaeghen, Marc [Institut fuer Kernphysik, Johannes Gutenberg Universitaet Mainz, D-55099 Mainz (Germany)

2010-11-01

176

Time domain electromagnetic metal detectors  

SciTech Connect

This presentation focuses on illustrating by case histories the range of applications and limitations of time domain electromagnetic (TDEM) systems for buried metal detection. Advantages claimed for TDEM metal detectors are: independent of instrument response (Geonics EM61) to surrounding soil and rock type; simple anomaly shape; mitigation of interference by ambient electromagnetic noise; and responsive to both ferrous and non-ferrous metallic targets. The data in all case histories to be presented were acquired with the Geonics EM61 TDEM system. Case histories are a test bed site on Molokai, Hawaii; Fort Monroe, Virginia; and USDOE, Rocky Flats Plant. The present limitations of this technology are: discrimination capabilities in terms of type of ordnance, and depth of burial is limited, and ability of resolving targets with small metallic ambient needs to be improved.

Hoekstra, P.

1996-04-01

177

Electromagnetic Activation of Capillary Switches  

NASA Astrophysics Data System (ADS)

By designing coupled droplet pairs with the appropriate length scale to promote surface tension as the dominant force, one can create bi-stable capillary switches. This bi-stability can be triggered by pressure pulses, surface chemistry, electroosmosis, or body forces. To exploit the latter, we designed a capillary switch with electromagnetic activation. The resulting setup consists of a sub-millimeter tube, overfilled with a ferrofluid, surrounded by a wire coil to generate a magnetic field. Evidence of this capillary switching will be presented along with some theoretical basis in fluid- and electro-dynamics. The approach may also be used to investigate other transport phenomena in electromagnetically-coupled microfluidic systems, including the relative effects of translational motion of the ferrofluid (both particles and solvent molecules) versus the rotational effects of the individual magnetic grains. These individually addressable capillary switches offer intriguing applications including high-speed adaptive optics, actuators at the microscale, and possible PCB integration.

Malouin, Bernie; Dayal, Rohan; Parsa, Leila; Hirsa, Amir

2008-11-01

178

Electromagnetic tracking for catheter localization  

NASA Astrophysics Data System (ADS)

A low frequency AC electromagnetic tracking system is presented that is capable of determining the position and orientation of a catheter tip. Advantages of using magnetic tracking for this application is that magnetic fields are non-ionizing and pass through the human body with minimal attenuation. Low frequency fields are used to mitigate the effects of eddy currents induced in conductive materials found in the environment. There are two significant differences between this and other magnetic tracking technologies, these being (1) the use of a single magnetic sensing coil for position and orientation determination and (2) the eliminating of range restrictions between the sensing antenna and the magnetic field generators. This paper will discuss the general theory of electromagnetic tracking, why it is that researchers have an intense interest for internal tracking and a comparison of the new and old tracking technologies. Some applications of this tracking technology will also be presented.

Schneider, Mark R.

1999-07-01

179

Falling Magnets and Electromagnetic Braking  

NASA Astrophysics Data System (ADS)

The slow fall of a rare earth magnet through a copper pipe is a striking example of electromagnetic braking; this remarkable phenomenon has been the subject of a number of scientific paper s [1, 2]. In a pipe having radius R and wall thickness D, the terminal velocity of the falling magnet is proportional to (R?4)/D. It is interesting to ask what happens in the limit as D becomes very large. We report our experimental observations and theoretical predictions of the dependence of the terminal velocity on pipe radius R for large D. [1] Y. Levin, F.L. da Silveira, and F.B. Rizzato, ``Electromagnetic braking: A simple quantitative model''. American Journal of Physics, 74(9): p. 815-817 (2006). [2] J.A. Pelesko, M. Cesky, and S. Huertas, Lenz's law and dimensional analysis. American Journal of Physics, 3(1): p. 37-39. 2005.

Culbreath, Christopher; Palffy-Muhoray, Peter

2009-03-01

180

Electromagnetic response of Weyl semimetals.  

PubMed

It has been suggested recently, based on subtle field-theoretical considerations, that the electromagnetic response of Weyl semimetals and the closely related Weyl insulators can be characterized by an axion term ?E·B with space and time dependent axion angle ?(r,t). Here we construct a minimal lattice model of the Weyl medium and study its electromagnetic response by a combination of analytical and numerical techniques. We confirm the existence of the anomalous Hall effect expected on the basis of the field theory treatment. We find, contrary to the latter, that chiral magnetic effect (that is, ground state charge current induced by the applied magnetic field) is absent in both the semimetal and the insulator phase. We elucidate the reasons for this discrepancy. PMID:23889433

Vazifeh, M M; Franz, M

2013-07-09

181

Electromagnetic-gravitational energy systems  

Microsoft Academic Search

Two methods are considered to 'tap' the earth's rotational energy. This ancient 'collapsed gravitational energy' exceeds the earth-lunar binding energy. One involves an orbiting 'electromagnetic-gravitational' coupling system whereby the earth's rotation, with its nonuniform mass distribution, first uses gravity to add orbital energy to a satellite, similar to a planetary 'flyby'. The second stage involves enhanced satellite 'drag' as current-carrying

K. H. Schatten

1981-01-01

182

Electromagnetic-gravitational energy systems  

Microsoft Academic Search

Two methods axe considered to “tap” the earths' rotational energy. This ancient “collapsed gravitational energy” exceeds the earth-lunar binding energy. One involves an orbiting “electromagnetic-gravitational” coupling system whereby the earth's rotation, with its nonuniform mass distribution, first uses gravity to add orbital energy to a satellite, similar to a planetary “flyby.rd The second stage involves enhanced satellite “drag” as current-carrying

Kenneth H. Schatten

1981-01-01

183

Electromagnetic Spectrum of Am241  

Microsoft Academic Search

The electromagnetic spectrum of Am241 has been studied with a ten-inch bent-crystal spectrometer and a sodium iodide scintillation counter. Twelve gamma rays, sixteen Np L x-rays, and eight Am L x-rays have been measured. The gamma rays in Np have energies of 26.363, 33.199, 43.463, 59.568, 103, 113, 130, 159, 210, 270, 328, and 370 kev. The x-ray energies establish

Paul P. Day

1955-01-01

184

Electromagnetic Spectrum of Radium D  

Microsoft Academic Search

The electromagnetic spectrum of RaD has been studied by the proportional counter spectrometry technique. The work of the Curie Laboratory on the gamma-ray spectrum has been generally confirmed. However, the presumed K x-ray lines are of much lower intensity and occur at a lower energy than previously reported. The L x-ray intensity is 22 per hundred disintegrations, indicating 0.63 conversion

P. E. Damon; R. R. Edwards

1953-01-01

185

Electromagnetic Spectrum from QGP Fluid  

Microsoft Academic Search

We calculate thermal photon and electron pairdistribution from hot QCD matter produced in high energy heavy-ion collisions, based on a hydrodynamical model which is so tuned as to reproduce the recent experimental data at CERN SPS, and compare these electromagnetic spectra with experimental data given by CERN WA80 and CERES. We investigate mainly the effects of the off-shell properties of

Tetsufumi Hirano; Shin Muroya; Mikio Namiki

1997-01-01

186

Electromagnetic compatibility in hospital corridors  

Microsoft Academic Search

The proposal that electromagnetic compatibility (EMC) in healthcare be fostered by using a free-space minimal-separation criterion between radio frequency (RF) sources of given power and medical devices of given immunity is evaluated. Electric fields within various corridors of a hospital were measured and the residuals of the fields from both slow-fade characteristics, and from free-space field predictions were computed. Measured

D. Davis; B. Segal; A. Cinquino; K. Hoege; R. Mastrocola; T. Pavlasek

1999-01-01

187

ELECTROMAGNETIC MODELING OF RETINAL PHOTORECEPTORS  

Microsoft Academic Search

Abstract—New electromagnetic models for the rods and,cones that are the,photoreceptors at,the,back,of the,retina are developed and simulated in order to explain the roles of dimension, geometrical structure, directional sensitivity and visual pigments of the photoreceptors in the reception of visible light. The rods and cones are modeled as uniform and quasi-tapered helical antennas, respectively. The results of the model study show

Cahit Canbay

2008-01-01

188

Computer animation of electromagnetic phenomena  

Microsoft Academic Search

A post-processing graphic package has been developed for the computer animation of 2D as well as 3D electromagnetic fields obtained from various finite element programs available at IGTE. The goal was to use relatively inexpensive and commonly available personal computers (e.g. 486\\/33 MHz systems or better) for this purpose because they have the further benefit of good transportability, advantageous at

K. Preis; I. Bardi; O. Biro; R. Hoschek; M. Mayr; U. Peterlini; K. R. Richter; I. Ticar

1995-01-01

189

GENETIC EFFECTS OF ELECTROMAGNETIC WAVES  

Microsoft Academic Search

The genetic effects of electromagnetic waves can be detected by different test-systems. The mutagenic effect of ionizing radiation\\u000a can be developed on the levels of DNA and\\/or chromosomes. In numerous researches efficiency of micronucleus assay, alkaline\\u000a single-cell gel electrophoresis, chromosomal aberrations test and FISH-technique and their different combinations for the\\u000a detection of ionizing radiation-induced genotoxic effects are discussed. Also some

Rouben Aroutiounian; Galina Hovhannisyan; Gennady Gasparian

190

Electromagnetic scattering in polarizable backgrounds  

Microsoft Academic Search

We develop a fully vectorial formalism for the investigation of electromagnetic scattering in polarizable backgrounds, i.e., where the scatterers are not in vacuum but situated in a medium with a dielectric permittivity different from unity. Our approach is based on the Green's tensor technique and the corresponding Green's tensors for two-dimensional ~2D! and three-dimensional ~3D! systems are developed. The analysis

Olivier J. F. Martin; Nicolas B. Piller

1998-01-01

191

Genetic algorithms in engineering electromagnetics  

Microsoft Academic Search

This paper presents a tutorial and overview of genetic algorithms for electromagnetic optimization. Genetic-algorithm (GA) optimizers are robust, stochastic search methods modeled on the concepts of natural selection and evolution. The relationship between traditional optimization techniques and the GA is discussed. Step-by-step implementation aspects of the GA are detailed, through an example with the objective of providing useful guidelines for

J. Michael Johnson; V. Rahmat-Samii

1997-01-01

192

Electromagnetic fields stress living cells  

Microsoft Academic Search

Electromagnetic fields (EMF), in both ELF (extremely low frequency) and radio frequency (RF) ranges, activate the cellular stress response, a protective mechanism that induces the expression of stress response genes, e.g., HSP70, and increased levels of stress proteins, e.g., hsp70. The 20 different stress protein families are evolutionarily conserved and act as ‘chaperones’ in the cell when they ‘help’ repair

Martin Blank; Reba Goodman

2009-01-01

193

Genetic Effects of Electromagnetic Waves  

NASA Astrophysics Data System (ADS)

The genetic effects of electromagnetic waves can be detected by different test-systems. The mutagenic effect of ionizing radiation can be developed on the levels of DNA and/or chromosomes. In numerous researches efficiency of micronucleus assay, alkaline single-cell gel electrophoresis, chromosomal aberrations test and FISH-technique and their different combinations for the detection of ionizing radiation-induced genotoxic effects are discussed. Also some molecular-biological approaches developed in the last years are presented.

Aroutiounian, Rouben; Hovhannisyan, Galina; Gasparian, Gennady

194

Electromagnetism on anisotropic fractal media  

NASA Astrophysics Data System (ADS)

Basic equations of electromagnetic fields in anisotropic fractal media are obtained using a dimensional regularization approach. First, a formulation based on product measures is shown to satisfy the four basic identities of the vector calculus. This allows a generalization of the Green-Gauss and Stokes theorems as well as the charge conservation equation on anisotropic fractals. Then, pursuing the conceptual approach, we derive the Faraday and Ampère laws for such fractal media, which, along with two auxiliary null-divergence conditions, effectively give the modified Maxwell equations. Proceeding on a separate track, we employ a variational principle for electromagnetic fields, appropriately adapted to fractal media, so as to independently derive the same forms of these two laws. It is next found that the parabolic (for a conducting medium) and the hyperbolic (for a dielectric medium) equations involve modified gradient operators, while the Poynting vector has the same form as in the non-fractal case. Finally, Maxwell's electromagnetic stress tensor is reformulated for fractal systems. In all the cases, the derived equations for fractal media depend explicitly on fractal dimensions in three different directions and reduce to conventional forms for continuous media with Euclidean geometries upon setting these each of dimensions equal to unity.

Ostoja-Starzewski, Martin

2013-04-01

195

Fluctuating electromagnetic fields of solids  

NASA Astrophysics Data System (ADS)

Various theoretical methods to calculate the spectral and correlation properties of fluctuating electromagnetic fields generated by solids are reviewed, all of which essentially reduce to solving the Maxwell equations for a specified geometry and boundary conditions and then using the fluctuation-dissipation theorem. The spectral and correlation properties of thermally stimulated fields of a system in equilibrium and out of equilibrium with surrounding bodies are described. A special attention is put to the difference between the spectral and correlation properties of the propagating and evanescent waves of the thermally stimulated fields of solids. The dispersion interaction between solid bodies in different thermodynamic states, the resonance dispersion interaction in a three-body system, the fluctuating fields as a means of body-to-body energy transfer, and the shift, broadening, and deexcitation of energy levels in a particle near a solid surface are discussed using the theory of thermally stimulated electromagnetic fields. Thermally stimulated emission of infrared radiation of semiconductor crystals and films (heated up to 150 °C) on metal substrates are measured in frequency range of vibrational polaritons both for propagating waves and for evanescent waves transformed into propagating waves due to ATR prism over the samples. The experimental results on thermally stimulated electromagnetic fields from solids are in qualitative and quantitative agreement with model calculations and theoretical expectations.

Dorofeyev, I. A.; Vinogradov, E. A.

2011-07-01

196

Fabrication of electromagnetic micromirror array  

NASA Astrophysics Data System (ADS)

This paper describes the design, fabrication and experiments of a micromirror array driven by electromagnetic force for right angle beam reflection to the vertical direction of the substrate. The device was fabricated using aluminum surface micromachining combined with nickel electroplating. The micromirror has couple of torsional springs enough long for 45 degree rotation, which angular deflection is necessary for right angle beam reflection. Also micromirror has a magnetic material for electromagnetic operation, and it has a mechanical stopper for angular deflection control. The main structural material is evaporated aluminum, and magnetic material is electroplated nickel. Thick photoresist is used as a sacrificial layer, and it is removed by oxygen plasma process. Electromagnetic characteristics were measured to find that about 10kA/m magnetic field intensity is needed for 45 degrees angular deflection. 25V to approximately 50V clamping voltage is required for selectively operation between the array within the external magnetic field. The dynamic response measurement was fulfilled using He-Ne laser and position sensitive diode (PSD). The lapsed time to reach 45 degrees is less than 0.5ms. But upward spring bending prevents the stopper from touching the substrate, so some oscillations corresponding to natural response is observed.

Jang, YunHo; Kim, Yong-Kweon

2001-09-01

197

Electromagnetic Effects in SDF Explosions  

SciTech Connect

The notion of high ion and electron concentrations in the detonation of aluminized explosive mixtures has aroused some interest in electro-magnetic effects that the SDF charges might generate when detonated. Motivated by this interest we have started to investigate whether significant electro-magnetic effects show up in our small-scale experiments. However, the design of instrumentation for this purpose is far from straightforward, since there are a number of open questions. Thus the main aim of the feasibility tests is to find - if possible - a simple and reliable method that can be used as a diagnostic tool for electro-magnetic effects. SDF charges with a 0.5-g PETN booster and a filling of 1 g aluminum flakes have been investigated in three barometric bomb calorimeters with volumes ranging from 6.3 l to of 6.6 l. Though similar in volume, the barometric bombs differed in the length-to-diameter ratio. The tests were carried out with the bombs filled with either air or nitrogen at ambient pressure. The comparison of the test in air to those in nitrogen shows that the combustion of TNT detonation products or aluminum generates a substantial increase of the quasi-steady overpressure in the bombs. Repeated tests in the same configuration resulted in some scatter of the experimental results. The most likely reason is that the aluminum combustion in most or all cases is incomplete and that the amount of aluminum actually burned varies from test to test. The mass fraction burned apparently decreases with increasing aspect ratio L/D. Thus an L/D-ratio of about 1 is optimal for the performance of shock-dispersed-fuel combustion. However, at an L/D-ratio of about 5 the combustion still yields appreciable overpressure in excess of the detonation. For a multi-burst scenario in a tunnel environment with a number of SDF charges distributed along a tunnel section a spacing of 5 tunnel diameter and a fuel-specific volume of around 7 l/g might provide an acceptable compromise between optimizing the combustion performance and keeping the number of elementary charges low. Further tests in a barometric bomb calorimeter of 21.2 l volume were performed with four types of aluminum. The mass fraction burned in this case appeared to depend on the morphology of the aluminum particles. Flake aluminum exhibited a better performance than granulated aluminum with particle sizes ranging from below 25 {micro}m to 125 {micro}m for the coarsest material. In addition, a feasibility study on electro-magnetic effects from SDF charges detonated in a tunnel has been performed. A method was developed to measure the local, unsteady electro-conductivity in the detonation/combustion products cloud. This method proved to yield reproducible results. A variety of methods were tested with regard to probing electro-magnetic pulses from the detonation of SDF charges. The results showed little reproducibility and were small compared to the effect from pulsed high voltage discharges of comparatively small energy (around 32 J). Thus either no significant electromagnetic pulse is generated in our small-scale tests or the tested techniques have to be discarded as too insensitive or too limited in bandwidth to detect possibly very high frequency electro-magnetic disturbances.

Reichenbach, H; Neuwald, P; Kuhl, A L

2010-02-12

198

Applied Computational Electromagnetics Society Journal. Computer Applications in Electromagnetics Education. Special Issue. Volume 8, Number 1.  

National Technical Information Service (NTIS)

The Applied Computational Electromagnetics Society Journal is devoted to the exchange of information in computational electromagnetics, to the advancement of the state-of-the-art, and to the promotion of related technical activities. A primary objective o...

M. Iskander

1993-01-01

199

Statistical theory of electromagnetic weak turbulence  

SciTech Connect

The weak turbulence theory as commonly found in the literature employs electrostatic approximation and is applicable to unmagnetized plasmas only. To this date, fully electromagnetic generalization of the existing weak turbulence theory based upon statistical mechanical approach remains largely incomplete. Instead, electromagnetic effects are incorporated into the weak turbulence formalism by means of the semiclassical approach. The present paper reformulates the fully electromagnetic weak turbulence theory from classical statistical mechanical (i.e., the Klimontovich) approach.

Yoon, Peter H. [Institute for Physical Science and Technology, University of Maryland, College Park, Maryland 20742-2431 (United States)

2006-02-15

200

Electromagnetic wave in a relativistic magnetized plasma  

SciTech Connect

Results are presented from a theoretical investigation of the dispersion properties of a relativistic plasma in which an electromagnetic wave propagates along an external magnetic field. The dielectric tensor in integral form is simplified by separating its imaginary and real parts. A dispersion relation for an electromagnetic wave is obtained that makes it possible to analyze the dispersion and collisionless damping of electromagnetic perturbations over a broad parameter range for both nonrelativistic and ultrarelativistic plasmas.

Krasovitskiy, V. B. [Russian Academy of Sciences, Keldysh Institute of Applied Mathematics (Russian Federation)

2009-12-15

201

Electromagnetic wave scattering by Schwarzschild black holes.  

PubMed

We analyze the scattering of a planar monochromatic electromagnetic wave incident upon a Schwarzschild black hole. We obtain accurate numerical results from the partial wave method for the electromagnetic scattering cross section and show that they are in excellent agreement with analytical approximations. The scattering of electromagnetic waves is compared with the scattering of scalar, spinor, and gravitational waves. We present a unified picture of the scattering of all massless fields for the first time. PMID:19658920

Crispino, Luís C B; Dolan, Sam R; Oliveira, Ednilton S

2009-06-11

202

Modeling of Nonlaminated Electromagnetic Suspension Systems  

Microsoft Academic Search

Eddy currents induced within nonlaminated electromagnetic actuators by time-varying magnetic fields have a strong effect on the dynamics and control of electromagnetic suspension systems. This paper examines the modeling of these suspension systems and resolves two important problems: 1) the effect of time-varying flotor position on electromagnetic force production and 2) the proper manner in which to model voltage-mode operation

Lei Zhu; Carl R. Knospe

2010-01-01

203

Electromagnetic noise in McElroy Mine  

Microsoft Academic Search

Two different techniques were used to make measurements of the absolute value of electromagnetic noise in and above an operating coal mine. McElroy Mine, located near Moundsville, West Virginia. A 300-volt-dc and 480-volt-ac machinery was measured to see the electromagnetic environment it created. One technique measures noise over the entire electromagnetic spectrum of interest for brief time periods. It is

M. Kanda; J. W. Adams; W. D. Bensema

1974-01-01

204

Molecular Expressions: Science, Optics & You: Electromagnetic Radiation  

NSDL National Science Digital Library

This item is an interactive Java simulation on electromagnetic radiation, the family of wave-like phenomena which includes visible light. Users control amplitude and wavelength to explore how electromagnetic waves are propagated. Included is a detailed text tutorial. This item is part of a larger collection of reference materials and simulations on electricity and magnetism. See Related Materials on this page for links to additional materials by these authors on electromagnetic radiation.

Davidson, Michael; Abramowitz, Mortimer; Parry-Hill, Matthew J.

2008-08-21

205

An electromagnetic analogue of gravitational wave memory  

NASA Astrophysics Data System (ADS)

We present an electromagnetic analogue of gravitational wave memory. That is, we consider what change has occurred to a detector of electromagnetic radiation after the wave has passed. Rather than a distortion in the detector, as occurs in the gravitational wave case, we find a residual velocity (a ‘kick’) to the charges in the detector. In analogy with the two types of gravitational wave memory (‘ordinary’ and ‘nonlinear’) we find two types of electromagnetic kick.

Bieri, Lydia; Garfinkle, David

2013-10-01

206

Constraint propagation through electromagnetic interaction topologies  

Microsoft Academic Search

The effects of electromagnetic interactions in electrical systems are of concern because of the increasing susceptibility of system components. Heuristic methods are used by engineers to solve electromagnetic interaction problems. An approximate symbolic knowledge representation of a single emitter\\/path\\/susceptor problem has been described. In this paper the approximate single emitter\\/path\\/susceptor attributes are distributed throughout the electromagnetic topology of a complex

Joe Lovetri; Darin P. W. Graham

1990-01-01

207

MUSES: multi-sensor soil electromagnetic sounding  

NASA Astrophysics Data System (ADS)

The authors describe the performance of a multi-sensor package designed to measure the electromagnetic properties of the subsurface during future landing missions to Mars. The package consists of a soil dielectric spectroscopy probe (SDSP), a ground penetrating radar (GPR) and a time domain electromagnetic measurement (TDEM) system that, using different methods, estimate the electromagnetic properties of the shallow subsurface at different depths (0- 100 m). A data fusion approach is considered to improve the reliability and accuracy of the measurements.

Vannaroni, G.; Pettinelli, E.; Ottonello, C.; Cereti, A.; Della Monica, G.; Del Vento, D.; Di Lellis, A. M.; Di Maio, R.; Filippini, R.; Galli, A.; Menghini, A.; Orosei, R.; Orsini, S.; Pagnan, S.; Paolucci, F.; Pisani, A. R.; Schettini, G.; Storini, M.; Tacconi, G.

2004-01-01

208

Broadband electromagnetic cloaking of long cylindrical objects.  

PubMed

Electromagnetic cloaks are devices that make objects undetectable for probing with electromagnetic waves. The known realizations of transformational-optics cloaks require materials with exotic electromagnetic properties and offer only limited performance in narrow frequency bands. Here, we demonstrate a wideband and low-loss cloak whose operation is not based on the use of exotic electromagnetic materials, which are inevitably dispersive and lossy. Instead, we use a simple structure made of metal layers. In this Letter, we present an experimental demonstration of cloaking for microwaves and simulation results for cloaking in the visible range. PMID:19792314

Tretyakov, Sergei; Alitalo, Pekka; Luukkonen, Olli; Simovski, Constantin

2009-09-03

209

Detection of electromagnetic waves using MEMS antennas  

SciTech Connect

We describe the design, fabrication and characterization of simple micromechanical structures that are capable of sensing static electric time varying electromagnetic fields. Time varying electric field sensing is usually achieved using an electromagnetic antenna and a receiver. However, these antenna-based approaches do not exhibit high sensitivity over a broad frequency (or wavelength) range. An important aspect of the present work is that, in contrast to traditional antennas, the dimensions of these micromechanical oscillators can be much smaller than the wavelength of the electromagnetic wave. We characterized the fabricated micromechanical oscillators by measuring their responses to time varying electric and electromagnetic fields.

Lavrik, Nickolay V [ORNL; Tobin, [Oak Ridge National Laboratory (ORNL); Bowland, Landon T [ORNL

2011-01-01

210

Electromagnetic compatibility of nuclear power plants  

SciTech Connect

Lately, there has been a mounting concern about the electromagnetic compatibility of nuclear-power-plant systems mainly because of the effects due to the nuclear electromagnetic pulse, and also because of the introduction of more-sophisticated and, therefore, more-susceptible solid-state devices into the plants. Questions have been raised about the adequacy of solid-state-device protection against plant electromagnetic-interference sources and transients due to the nuclear electromagnetic pulse. In this paper, the author briefly reviews the environment, and the coupling, susceptibility, and vulnerability assessment issues of commercial nuclear power plants.

Cabayan, H.S.

1983-01-01

211

Libration Controller of Electromagnetic Vehicle Vibrator  

NASA Astrophysics Data System (ADS)

Electromagnetic Vehicle Vibrator is a non-explosive seismic source, for high resolution detection of underground information, which is used for mineral resources reconnaissance and detecting special target underground abroadly. The work principle comes from Chirp radar technique, the main task is sending Chirp signal with strict controlled parameter to underground. The Chirp signal produced by Electromagnetic Vehicle Vibrator is sent to underground by power amplification and vibrator drived electromagnetism. So the quality of signal influences the whole performance index of seismic explosive system. This thesis discusses hardware and sorfware of Electromagnetic Vehicle Vibrator.

Sun, F.; Chen, Z. B.

2006-10-01

212

Introduction to the special issue on high-power electromagnetics (HPEM) and intentional electromagnetic interference (IEMI)  

Microsoft Academic Search

A new threat to civil society has recently emerged. It is known as intentional electromagnetic interference (IEMI) and covers the threat of intense electromagnetic disturbances that may be applied to the sophisticated electronic systems that are so important to our daily lives. This paper provides a brief background for the threat, defines important terms, describes the different types of electromagnetic

William A. Radasky; Carl E. Baum; Manuem W. Wik

2004-01-01

213

Electromagnetic fields in fractal continua  

NASA Astrophysics Data System (ADS)

Fractal continuum electrodynamics is developed on the basis of a model of three-dimensional continuum ?D3?E3 with a fractal metric. The generalized forms of Maxwell equations are derived employing the local fractional vector calculus related to the Hausdorff derivative. The difference between the fractal continuum electrodynamics based on the fractal metric of continua with Euclidean topology and the electrodynamics in fractional space F? accounting the fractal topology of continuum with the Euclidean metric is outlined. Some electromagnetic phenomena in fractal media associated with their fractal time and space metrics are discussed.

Balankin, Alexander S.; Mena, Baltasar; Patiño, Julián; Morales, Daniel

2013-04-01

214

An electromagnetic world without polarization  

NASA Astrophysics Data System (ADS)

The majority of natural sources (black-bodies, fluorescent bulbs, etc) generate completely un-polarized light; the majority of detectors (eyes, photo-cameras, photomultipliers, etc) are polarization-insensitive. To reflect this, we attempt to describe approximately electromagnetic waves without polarization. Corresponding scalar equations are non-trivial modifications of standard d’Alembert and Helmholtz equations to the case of spatially inhomogeneous propagation speed v(\\mathbf{r})=1/\\sqrt{\\varepsilon (\\mathbf{r})\\mu (\\mathbf{r})}. A description of Fresnel reflection (FR) and Goos-Hänchen shift for total internal reflection phenomena is given on the basis of these modified equations.

Zeldovich, B. Ya; Tsai, C.-C.

2013-01-01

215

Electromagnetic weak turbulence theory revisited  

NASA Astrophysics Data System (ADS)

The statistical mechanical reformulation of weak turbulence theory for unmagnetized plasmas including fully electromagnetic effects was carried out by Yoon [Phys. Plasmas 13, 022302 (2006)]. However, the wave kinetic equation for the transverse wave ignores the nonlinear three-wave interaction that involves two transverse waves and a Langmuir wave, the incoherent analogue of the so-called Raman scattering process, which may account for the third and higher-harmonic plasma emissions. The present paper extends the previous formalism by including such a term.

Yoon, P. H.; Ziebell, L. F.; Gaelzer, R.; Pavan, J.

2012-10-01

216

Extremely low frequency electromagnetic fields  

SciTech Connect

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.

Wilson, B.W. (Pacific Northwest Lab., Richland, WA (USA). Chemical Sciences Dept.); Stevens, R.G. (Pacific Northwest Lab., Richland, WA (USA)); Anderson, L.E. (Pacific Northwest Lab., Richland, WA (USA). Life Sciences Center)

1990-01-01

217

Particle acceleration by electromagnetic waves.  

PubMed

We consider the symmetry in the interaction of photons and electrons, which has led to a common description of electron and photon accelerations; effects such as photon Landau damping arise naturally from such a treatment. Intense electromagnetic waves can act as a photon mirror to charged particles. The subsequent acceleration is equivalent to the photon pulse accelerating electrons. During the interaction or reflection process, the charged particle can emit bursts of radiation similar to the radiation emitted from the particles during wave breaking of plasma waves. PMID:18218605

Bingham, R

2008-05-28

218

Electromagnetic configurations of rail guns  

NASA Astrophysics Data System (ADS)

Some problems associated with the electromagnetic acceleration of macrobodies in a rail gun are examined. An approach to the design of rail gun configurations is proposed, and some basic rail gun schemes are synthesized. The alternative rail gun schemes are compared in terms of electrode potential and stability of the electrode gap with respect to parasitic current shunting. The effect of the ohmic resistance of the electrodes and of the additional magnetization field on the spatial structure of the discharge in the rail gun channel is discussed. A classification of rail gun modifications is presented.

Fat'yanov, O. V.; Ostashev, V. E.; Lopyrev, A. N.; Ul'Yanov, A. V.

1993-06-01

219

Covariant jump conditions in electromagnetism  

NASA Astrophysics Data System (ADS)

A generally covariant four-dimensional representation of Maxwell's electrodynamics in a generic material medium can be achieved straightforwardly in the metric-free formulation of electromagnetism. In this setup, the electromagnetic phenomena are described by two tensor fields, which satisfy Maxwell's equations. A generic tensorial constitutive relation between these fields is an independent ingredient of the theory. By use of different constitutive relations (local and non-local, linear and non-linear, etc.), a wide area of applications can be covered. In the current paper, we present the jump conditions for the fields and for the energy-momentum tensor on an arbitrarily moving surface between two media. From the differential and integral Maxwell equations, we derive the covariant boundary conditions, which are independent of any metric and connection. These conditions include the covariantly defined surface current and are applicable to an arbitrarily moving smooth curved boundary surface. As an application of the presented jump formulas, we derive a Lorentzian type metric as a condition for existence of the wave front in isotropic media. This result holds for ordinary materials as well as for metamaterials with negative material constants.

Itin, Yakov

2012-02-01

220

Compton Sources of Electromagnetic Radiation  

SciTech Connect

When a relativistic electron beam interacts with a high-field laser beam, intense and highly collimated electromagnetic radiation will be generated through Compton scattering. Through relativistic upshifting and the relativistic Doppler effect, highly energetic polarized photons are radiated along the electron beam motion when the electrons interact with the laser light. For example, X-ray radiation can be obtained when optical lasers are scattered from electrons of tens-of-MeV beam energy. Because of the desirable properties of the radiation produced, many groups around the world have been designing, building, and utilizing Compton sources for a wide variety of purposes. In this review article, we discuss the generation and properties of the scattered radiation, the types of Compton source devices that have been constructed to date, and the prospects of radiation sources of this general type. Due to the possibilities of producing hard electromagnetic radiation in a device that is small compared to the alternative storage ring sources, it is foreseen that large numbers of such sources may be constructed in the future.

Geoffrey Krafft,Gerd Priebe

2011-01-01

221

Electromagnetic Methods of Lightning Detection  

NASA Astrophysics Data System (ADS)

Both cloud-to-ground and cloud lightning discharges involve a number of processes that produce electromagnetic field signatures in different regions of the spectrum. Salient characteristics of measured wideband electric and magnetic fields generated by various lightning processes at distances ranging from tens to a few hundreds of kilometers (when at least the initial part of the signal is essentially radiation while being not influenced by ionospheric reflections) are reviewed. An overview of the various lightning locating techniques, including magnetic direction finding, time-of-arrival technique, and interferometry, is given. Lightning location on global scale, when radio-frequency electromagnetic signals are dominated by ionospheric reflections, is also considered. Lightning locating system performance characteristics, including flash and stroke detection efficiencies, percentage of misclassified events, location accuracy, and peak current estimation errors, are discussed. Both cloud and cloud-to-ground flashes are considered. Representative examples of modern lightning locating systems are reviewed. Besides general characterization of each system, the available information on its performance characteristics is given with emphasis on those based on formal ground-truth studies published in the peer-reviewed literature.

Rakov, V. A.

2013-08-01

222

Adaptive Multiscale Electromagnetic Particle Simulations  

NASA Astrophysics Data System (ADS)

Hybrid (massless fluid electrons, kinetic ions) and full electromagnetic PIC simulations have recently emerged as powerful computational tools for predicting energetic particle transport in large-scale plasma configurations. Multiple time and length scales associated with plasma and magnetic field inhomogeneities put severe restrictions on the timestep and mesh resolution in these applications. We present two approaches intended to relieve these issues. An asynchronous hybrid code, HYPERS discards traditional time stepping in favor of Discrete-Event Simulation (DES). DES adaptively selects time increments for individual particles and local electromagnetic fields by limiting their per-update changes. HYPERS has been designed to simulate 3D compact fusion devices (such as the SSX experiment at Swarthmore) and interactions of streaming plasmas with obstacles. To validate this new code, we compare results from 2D HYPERS simulations with those obtained with a traditional (time-stepped) hybrid code. We also discuss a novel subgridding (EMPOWER) algorithm for full EM-PIC simulations and demonstrate its efficiency on test problems. Both codes are being geared towards peta/exa-scale computer architectures. We report our undergoing efforts on developing efficient dynamic load-balancing strategies for parallel production runs.

Omelchenko, Y. A.; Karimabadi, H.; Brown, M.; Catalyurek, U. V.; Saule, E.

2010-11-01

223

Correlation theory of quantized electromagnetic field I  

Microsoft Academic Search

A correlation matrix is defined which describes arbitrary order correlation effects of the electromagnetic field. Dynamical equations are derived which govern the space-time development of the correlation matrix of the quantized electromagnetic field in vacuo. With the help of these equations, propagation laws and non-linear conservation laws for the correlation matrix are obtained.

R. Horák

1969-01-01

224

Electromagnetic models of the lightning return stroke  

Microsoft Academic Search

Lightning return-stroke models are needed for specifying the source in studying the production of transient optical emission (elves) in the lower ionosphere, the energetic radiation from lightning, and characterization of the Earth's electromagnetic environment, as well as studying lightning interaction with various objects and systems. Reviewed here are models based on Maxwell's equations and referred to as electromagnetic models. These

Yoshihiro Baba; Vladimir A. Rakov

2007-01-01

225

Challenges in bio-electromagnetic modeling  

Microsoft Academic Search

This paper accompanies a tutorial on challenges in bio-electromagnetic modeling. This is a broad multidisciplinary field which, of course, cannot be covered extensively within few pages. Yet, some of the central points can be highlighted nevertheless within a few examples from bio-medical engineering as there are: the typical multiscale character, the lack of good data on electromagnetic properties especially in

Carsten Potratz; Sabine Petersen; A. Grunbaum; U. van Rienen

2010-01-01

226

Suppressing electromagnetic interference in direct current converters  

Microsoft Academic Search

Since James Clerk Maxwell established the electromagnetic field theory in 1865, multifarious electrical and electronic products have been invented, designed, produced, and widely deployed, such as wireless communication devices, electrical machines and motors. This has profoundly changed our world and our lives. Now we cannot live without electrical products anymore and, thus, we are surrounded with electromagnetic fields generated. On

Hong Li; Zhong Li; Bo Zhang; Wallace Tang; Wolfgang Halang

2009-01-01

227

Wireless data transmission from inside electromagnetic fields  

Microsoft Academic Search

This paper describes analytical and experimental work developed to evaluate the effects of the electromagnetic fields produced by high-voltage lines (400 kV) on wireless data transmission at the 900 MHz band. In this work the source of the data transmission is located inside the electromagnetic field and the reception station is located at different distances from the power lines. Different

José Ignacio Huertas; Roberto Barraza; J. M. Echeverry

2009-01-01

228

Studies Of Apnea Monitor Radiofrequency Electromagnetic Interference  

Microsoft Academic Search

Reports that radiofrequency (RF) electromagnetic interference (EMI) was responsible for infant apnea (breath cessation) monitor disfunction have prompted an in-depth engineering investigation by the Center for Devices and Radiological Health (CDRH). Two studies were undertaken using several apnea monitors currently in use in the U.S. A laboratory study was done under controlled, repeatable conditions using a transverse electromagnetic (\\

P. S. Ruggera; Eugene R O'Bryan

1991-01-01

229

Bioelectromagnetic Effects of the Electromagnetic Pulse (EMP).  

National Technical Information Service (NTIS)

The public has expressed concern about the biological effects and hazards of non-ionizing electromagnetic fields produced by the electro-magnetic pulse (EMP) simulators that simulate the EMP emanating from a high-altitude nuclear explosion. This paper pro...

E. L. Patrick W. L. Vault

1990-01-01

230

Protecting the Power Grid From Electromagnetic Pulses  

Microsoft Academic Search

A nuclear explosion high in the Earth's atmosphere does no immediate known harm to living things, but the resulting electromagnetic pulse (EMP) from a single detonation could degrade 70 percent or more of the country's electrical service in an instant, warns the Commission to Assess the Threat to the United States from Electromagnetic Pulse Attack, which presented its findings to

Sarah Simpson

2004-01-01

231

Electromagnetic micro power generator — A comprehensive survey  

Microsoft Academic Search

This paper presents a comprehensive survey on vibration powered electromagnetic micro generator, which harvest mechanical energy from environment and convert this energy into useful electrical power for micro system and sensor node. The on-going research works on electromagnetic micro generator are reviewed as a background of this paper. Basic theories of micro generator to produce power from ambient motion by

Wong Chin Chye; Zuraini Dahari; Othman Sidek; Muhammad Azman Miskam

2010-01-01

232

Series and Parallel Experimenting with Electromagnets  

Microsoft Academic Search

The pull of electromagnets on weights acts through the magnetism evoked in iron by current flowing in wires coiled around that iron. Learning to work with this instrument entails engaging with how effects of current show different behavior under series and parallel connections of the wire windings. This experience was new for Joseph Henry when, around 1830, he devised electromagnets

Elizabeth Cavicchi

233

Interferences of electromagnetic field with biological matter  

Microsoft Academic Search

Interferences of electromagnetic field (EMF) with biological matter are first presented on the basis that EMF itself is a part of matter. Additionally, matter in its basic state (charged particles and electromagnetic fields) is electrical. Biological matter therefore represents processes which are fundamentally electrical. On the surface, these processes can be described as matter and function depending on more or

B. Nordenström; S. Ipavec; S. Alfas

1992-01-01

234

Electromagnetic Concepts in Mathematical Representation of Physics.  

ERIC Educational Resources Information Center

|Addresses the use of mathematics when studying the physics of electromagnetism. Focuses on common electromagnetic concepts and their associated mathematical representation and arithmetical tools. Concludes that most students do not understand the significant aspects of physical situations and have difficulty using relationships and models…

Albe, Virginie; Venturini, Patrice; Lascours, Jean

2001-01-01

235

Complete transformer model for electromagnetic transients  

Microsoft Academic Search

A complete, three phase transformer model for the calculation of electromagnetic transients is presented. The model consists of a set of state equations solved with the trapezoidal rule of integration in order to obtain an equivalent Norton circuit at the transformer terminals. Thus the transformer model can be easily interfaced with an electromagnetic transients program. Its main features are: (a)

F. de Leon; A. Semlyen

1994-01-01

236

Dynamics and control of electromagnetic satellite formations  

Microsoft Academic Search

Satellite formation flying is an enabling technology for many space missions, especially for space based telescopes. Electromagnetic formation flying (EMFF) is a novel concept that uses superconducting electromagnetic coils to provide forces and torques between different satellites in a formation. With EMFF the life-span of the mission becomes independent of the fuel. This comes at the cost of coupled and

Umair Ahsun; David W. Miller

2006-01-01

237

Influence of Electromagnetic Radiation on Enzyme Kinetics  

Microsoft Academic Search

This study is focused on experimental validation of our hypothesis proposed within the Resonant Recognition Model (RRM) [7], [8] that protein function can be modified by an applied electromagnetic radiation of defined frequency in a range of infrared (IR), visible and ultraviolet (UV) light. This postulate is investigated here by applying the electromagnetic radiation (1140-1200 nm) to example of L-Lactate

V. Vojisavljevic; E. Pirogova; I. Cosic

2007-01-01

238

Medical device electromagnetic interference-ANSI issues  

Microsoft Academic Search

Medical Device Electromagnetic Interference (EMI) is an interaction that may occur between electrical medical devices and other sources of electromagnetic energy. The United States Food and Drug Administration (FDA) has federal responsibility for the safety and efficacy of electrical medical devices and is deeply involved in the subject interaction. The American National Standards Institute (ANSI) has administered and coordinated the

DANIEL D. HOOLIHAN

1997-01-01

239

Walter Fendt Physics Applets: Electromagnetic Wave  

NSDL National Science Digital Library

This simulation shows a plane polarized electromagnetic wave propagating in positive x direction. The vectors of the electric field (red) are parallel to the y axis, the vectors of the magnetic field (blue) are parallel to the z axis. This applet illustrates the behavior of the fields in electromagnetic waves. This is part of a large collection of physics applets available in several languages.

Fendt, Walter

2007-01-29

240

Project Physics Tests 4, Light and Electromagnetism.  

ERIC Educational Resources Information Center

Test items relating to Project Physics Unit 4 are presented in this booklet. Included are 70 multiple-choice and 22 problem-and-essay questions. Concepts of light and electromagnetism are examined on charges, reflection, electrostatic forces, electric potential, speed of light, electromagnetic waves and radiations, Oersted's and Faraday's work,…

Harvard Univ., Cambridge, MA. Harvard Project Physics.

241

Narrow field electromagnetic sensor system and method  

DOEpatents

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.

McEwan, T.E.

1996-11-19

242

Project Physics Tests 4, Light and Electromagnetism.  

ERIC Educational Resources Information Center

|Test items relating to Project Physics Unit 4 are presented in this booklet. Included are 70 multiple-choice and 22 problem-and-essay questions. Concepts of light and electromagnetism are examined on charges, reflection, electrostatic forces, electric potential, speed of light, electromagnetic waves and radiations, Oersted's and Faraday's work,…

Harvard Univ., Cambridge, MA. Harvard Project Physics.

243

Electromagnetic backscattering from aircraft propeller blades  

Microsoft Academic Search

This paper gives a theoretical solution to the problem of determining the electromagnetic backscattering and Doppler spectrum of an aircraft propeller as presented to a radar operating in the 8-12 GHz band. At this band for all practical aircraft propeller the electromagnetic backscattering regime is in the optical region. The solution proceeds by modeling the aircraft propeller as a set

S. Y. Yang; S. M. Yeh; S. S. Bor; S. R. Huang; C. C. Hwang

1997-01-01

244

Wireless Phones Electromagnetic Field Radiation Exposure Assessment  

Microsoft Academic Search

Problem statement: Inadequate knowledge of electromagnetic field emit ted by mobile phones and increased usage at close proximity, crea ted a lot of skepticism and speculations among end users on its safety or otherwise. Approach: In this study, near field electromagnetic field ra diation measurements were conducted on different brand of mobile phones in active mode using a tri-axis isotropic

A. D. Usman; W. F. Wan Ahmad; Ab Kadir; M. Mokhtar

2009-01-01

245

Teaching Electromagnetic Radiation effects on Humans  

Microsoft Academic Search

We teach electromagnetics as part of a general education course in physics (for non science majors) in which we relate physics to societal issues. The course covers the effects of electromagnetic radiation on human beings. This discussion is limited to at most one class room period (about 50 minutes) usually less. There are several important conceptual issues that must be

David A. Larrabee

2006-01-01

246

Advantages of electromagnetic radiation in health  

Microsoft Academic Search

According to the concepts of electro medicine most of the diseases are caused by micro organisms. Electromagnetic radiation having many hazardous effects on human beings and other living forms has the other side of having disease curing effect. The killing and destructive power of electromagnetic radiation can be used constructively for curing the incurable diseases by eradicating the disease producing

S. T. S. R. Mohanaselvan

2003-01-01

247

Computational Techniques of Electromagnetic Dosimetry for Humans  

NASA Astrophysics Data System (ADS)

There has been increasing public concern about the adverse health effects of human exposure to electromagnetic fields. This paper reviews the rationale of international safety guidelines for human protection against electromagnetic fields. Then, this paper also presents computational techniques to conduct dosimetry in anatomically-based human body models. Computational examples and remaining problems are also described briefly.

Hirata, Akimasa; Fujiwara, Osamu

248

Narrow field electromagnetic sensor system and method  

DOEpatents

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.

McEwan, Thomas E. (Livermore, CA)

1996-01-01

249

The electromagnetic simulation software package MAFIA 4  

Microsoft Academic Search

MAFIA 4 is a general purpose electromagnetic simulation software package, which has found wide application in various research and industrial institutions. The program is based on the finite integration theory and covers all main aspects of this grid-based discrete electromagnetic field theory. New developments for MAFIA 4 are the TL3 code module for simulation of transient magnetoquasistatic fields including effects

M. Clemens; S. Drobny; H. Krugert; P. Pinder; O. Podebrad; B. Schillinger; B. Trapp; T. Weiland; M. Wilke; M. Bartsch; U. Becker; M. Zhang

1999-01-01

250

The SUMMA Graduate Fellowships in Advanced Electromagnetics  

Microsoft Academic Search

These fellowships are intended to promote exceptionally creative contributions to the advancement of electromagnetic theory and applications. They promote EM theory (conceptual, new ideas, new approaches), but with apparent potential applications (antennas, scattering, propagation, other EM devices). They will be awarded to graduate students studying electromagnetics for pursuit of the PhD. Such students may be currently MS or PhD candidates.

Alexander P. Stone

2009-01-01

251

Total kinetic energy of an electromagnetic body†  

Microsoft Academic Search

It is here proposed to extend the notion of the kinetic energy of a moving and deformable electromagnetic material. This extended form of kinetic energy, which we suggest naming total kinetic energy, is consistent with the classical expression of the kinetic energy, to which it reduces in the absence of electromagnetic fields. The proposed expression of the total kinetic energy

C. Trimarco

2005-01-01

252

Surface electromagnetic waves in cholesteric liquid crystals  

NASA Astrophysics Data System (ADS)

Surface electromagnetic waves propagating along the boundary of a cholesteric liquid crystal, represented by a coiled uniaxial medium, are examined analytically. An expression for surface electromagnetic waves is obtained by sewing together all attenuating solutions to the wave equation in the cholesteric liquid crystal and the substrate. Conditions for the existence of surface acoustic waves in the region of attenuating solutions are formulated.

Shiianovskii, S. V.

1987-07-01

253

Direct electromagnetic optimization of microwave filters  

Microsoft Academic Search

This article explores an optimization procedure for microwave filters and multiplexers. The procedure is initialized by a classical filter synthesis based on a segmented electromagnetic synthesis that provides the basic dimensions of the structure. The optimization loop, which combines a global electromagnetic analysis and a coupling identification, improves the structure response compared to an empirical optimization

S. Bila; D. Baillargeat; M. Aubourg; S. Verdeyme; P. Guillon; F. Seyfert; J. Grimm; L. Baratchart; C. Zanchi; J. Sombrin

2001-01-01

254

Hypnogenic action of a modulated electromagnetic field  

Microsoft Academic Search

The dynamics of behavioral and electroencephalographic changes in rats were studied during prolonged exposure to a modulated electromagnetic field (frequency 40 MHz, frequency of modulation 50 Hz, intensity 100–120 V\\/m). Exposure to a modulated electromagnetic field was found to cause the appearance of phasic disturbances in conditioned food and defensive reflexes or even the development of a cataleptic state. These

K. V. Sudakov; G. D. Antimonii

1977-01-01

255

Hydrodynamic construction of the electromagnetic field  

Microsoft Academic Search

We present an alternative Eulerian hydrodynamic model for the electromagnetic field in which the discrete vector indices in Maxwell's equations are replaced by continuous angular freedoms, and develop the corresponding Lagrangian picture in which the fluid particles have rotational and translational freedoms. This enables us to extend to the electromagnetic field the exact method of state construction proposed previously for

Peter Holland

2005-01-01

256

Charging Ahead: An Introduction to Electromagnetism  

NSDL National Science Digital Library

Charging Ahead: An Introduction to Electromagnetism is a set of hands-on activities designed to help teachers introduce middle and high school students to electromagnetism, one of the most fascinating and life changing phenomenon humankind has witnessed. In 1820, Hans Oersted, a Danish physicist and school teacher, discovered that an electrical current produces magnetism. This set the stage for the development of the electrical motor and generating electricity from motion and magnets. Charging Ahead uses readily available materials to introduce students to electromagnetism, to the factors that determine the strength of electrical coils, to the application of electromagnetism in the construction of an electrical motor, and to the production of electricity through the construction of a generator. Throughout the book, students are introduced to historical perspectives and to technological applications (circuit breakers, mag-lev trains, superconducting generators, etc.) of electromagnetism.

Schafer, Larry E.

2001-01-01

257

Electromagnetic anomaly before earthquakes measured by electromagnetic experiments  

NASA Astrophysics Data System (ADS)

Three experiments are carried out for earthquake monitoring using electromagnetic (EM) methods in recent years. Some earthquakes occurred in chance of the measurement time period for each experiment and the anomalies were recorded before the shocks. The observation at a site 20 km away from the epicenter of Zhangbei M S6.2 earthquake in 1998 shows that the apparent resistivity decreases in the strike direction before and/or during the earthquake and the resistivity increases in the decline direction. This anomalous variation in apparent resistivity accounts for about 20%. The apparent resistivities at a site in the epicentral area decrease in the strike and decline directions before and/or during the earthquake and increase after shocks. The experiments using artificial electromagnetic signals with super low frequency carried out in 1999 show that the resolution and stability of electric and magnetic spectra are improved. The spectra of electric and magnetic fields and apparent resistivity at the Baodi station began to anomalously change two days before the Qian’an earthquake with 120 km distant to the station. The anomalous variation of electric and magnetic spectra is about twice as great as normal variation and the apparent resistivity changes by about 20%. The measurements in active seismic area of Yunnan province in the year 2005 indicate that the electric and magnetic spectra anomalously change by one order before the Taoyuan earthquake about 100 km away from the observatories. But the measurements at the sites in Beijing area 2 000 km away from the epicenter do not show any anomaly.

Zhao, Guoze; Zhan, Yan; Wang, Lifeng; Wang, Jijun; Tang, Ji; Xiao, Qibin; Chen, Xiaobin

2009-08-01

258

Soil and site characterization using electromagnetic waves  

NASA Astrophysics Data System (ADS)

Success in geotechnical analysis, design, and construction invariably requires that we have proper knowledge and understanding of (1) the strength, (2) the fluid flow properties, and (3) the stress-deformation behavior of the earth materials. These important engineering properties are primarily determined by the components and structure of a soil, which also dictate the soil's responses in an electromagnetic field. As a nondestructive technique, electromagnetic property measurements offer a promising approach to characterize earth materials and identify the effects of changes in environments. However, despite many investigations in the last several decades, the relationship between the frequency-dependent electromagnetic properties of soils and their components and structure are still not well understood. Hence, estimation of engineering properties of a soil in a quantitative way from electromagnetic measurements can be uncertain. In this research several tasks have been accomplished: (1) Development of a physically based model that provides a means of investigating the coupled effects of important polarization mechanisms on soil electromagnetic properties, and a means of relating the electromagnetic properties of a soil to its fines content, clay mineralogy, anisotropy, degree of flocculation and pore fluid chemistry; (2) Deduction of the wide-frequency electromagnetic properties of a soil by measuring its responses to a step pulse voltage using time domain reflectometry (TDR); (3) Proposal of a practically applicable method to determine the volumetric water content, specific surface area and pore fluid salt concentration simultaneously from the dielectric spectrum; (4) Establishment of the relationships between the specific surface area, electromagnetic properties and compressibility, residual shear strength and hydraulic conductivity. This study establishes a framework for quantifying soil engineering properties from their electromagnetic properties. If properly determined and interpreted, the electromagnetic properties can also provide insights into the causes of soil property changes over time and can be very useful in studying the effects of biological factors in geotechnical engineering, a field that may offer great potential for future advances.

Liu, Ning

259

Electromagnetic studies in geothermal regions  

NASA Astrophysics Data System (ADS)

During the past 25 yr, nearly all available electromagnetic and geoelectric techniques have been tested for their usefulness in geothermal exploration and exploitation. Dipole-dipole profiling, audiomagnetotellurics and controlled source electromagnetic methods are examples of those which have proven to be rather efficient for geothermal exploration. From the hundreds of field surveys which have been performed in many geothermal regions of the world, a large variety of geothermal regions and local geothermal systems, with different geological, hydrological and heat transfer characteristics, has been found to exist. Depending on the combination of these different characteristics each geothermal region or system presents a new problem which may need a different field technique or group of field techniques for optimal exploration. Despite these problems, new geothermal regions have been detected and structures and processes in geothermal systems are now much better understood. For example, advances have been made in the study of (a) the characteristics of porous/permeable hot water/vapor reservoirs and of fractioned zones for hot water/vapor circulation and production (b) the distribution and movement of cold meteoric and of hot water (c) the thermal insulation of reservoirs by cap-rocks (d) convective and/or conductive heat transfer and (e) the thermal influence of magma intrusions to high crustal levels. New exploration techniques, data analysis procedures and model calculations have been developed in the course of research in geothermal areas. They include the controlled source electromagnetic methods, the remote reference field technique and the development of better and faster algorithms for direct and inverse model calculations. Problems for the future are (a) the development and improvement of equipment and field techniques for more precise delineation and resolution of the conductivity distribution in geothermal areas especially those with productive zones of high porosity/permeability and fracturing, (b) the improvement of computerised data analysis in the field to optimise progress during the field measurements and (c) the development of more efficient interpretation procedures for the rather inhomogeneous conductivity distribution which exists in most geothermal areas.

Berktold, A.

1983-07-01

260

Pain perception and electromagnetic fields.  

PubMed

A substantial body of evidence has accumulated showing that exposure to electromagnetic fields (EMFs) affects pain sensitivity (nociception) and pain inhibition (analgesia). Consistent inhibitory effects of acute exposures to various EMFs on analgesia have been demonstrated in most studies. This renders examinations of changes in the expression of analgesia and nociception a particularly valuable means of addressing the biological effects of and mechanisms underlying the actions of EMFs. Here we provide an overview of the effects of various EMFs on nociceptive sensitivity and analgesia, with particular emphasis on opioid-mediated responses. We also describe the analgesic effects of particular specific EMFs, the effects of repeated exposures to EMFs and magnetic shielding, along with the dependence of EMF effects on lighting conditions. We further consider some of the underlying cellular and biophysical mechanisms along with the clinical implications of these effects of various EMFs. PMID:17374395

Del Seppia, Cristina; Ghione, Sergio; Luschi, Paolo; Ossenkopp, Klaus-Peter; Choleris, Elena; Kavaliers, Martin

2007-02-14

261

Electromagnetic Induction with Neodymium Magnets  

NASA Astrophysics Data System (ADS)

In April 1820, Hans Christian Ørsted noticed that the needle of a nearby compass deflected briefly from magnetic north each time the electric current of the battery he was using for an unrelated experiment was turned on or off. Upon further investigation, he showed that an electric current flowing through a wire produces a magnetic field. In 1831 Michael Faraday and Joseph Henry separately expanded on Ørsted's discovery by showing that a changing magnetic field produces an electric current. Heinrich Lenz found in 1833 that an induced current has the opposite direction from the electromagnetic force that produced it. This paper describes an experiment that can help students to develop an understanding of Faraday's law and Lenz's law by studying the emf generated as a magnet drops through a set of coils having increasing numbers of turns.

Wood, Deborah; Sebranek, John

2013-09-01

262

Electromagnetic launcher: A new weapon  

NASA Astrophysics Data System (ADS)

There are several perceived advantages to using Electromagnetic (EM) launching for weapons applications. Higher muzzle velocities than can be achieved with conventional ordnance will minimize the projectile time-of-flight to the target; this is of particular interest for air-defense applications against maneuvering targets and for penetrator launching. The potential for precise current (hence acceleration) control promises lower peak accelerations that the projectile must withstand, and much more precise muzzle velocity control, permitting the use of smart projectiles and continuous zoning for artillery applications. The principles behind EM accelerators, particularly dc accelerators (railguns), the recent history of their development, their advantages for weapons applications, the general requirements, potential problem areas that must be faced by designers, and the work that has been done by researchers at Livermore and Los Alamos National Laboratories in accelerating 3-g projectiles to 10 km/s, and larger masses to lower velocities are discussed.

Brooks, A. L.; Hawke, R. S.

1981-08-01

263

Broadband cavity electromagnetically induced transparency  

SciTech Connect

Cavity electromagnetically induced transparency (EIT) is created in a three-level atomic system confined in a cavity and coupled to a free-space control laser and is manifested as a narrow transmission peak of a probe laser coupled into the cavity mode and tuned to the two-photon Raman resonance with the control laser. Cavity EIT can be observed with a control laser detuned from the atomic transition frequency in a range limited by the vacuum Rabi splitting of two cavity-atom normal modes. This leads to the broadband cavity EIT obtained in the coupled-cavity-atom system with a free-space, broadband control laser. We report an experimental observation of broadband cavity EIT in cold Rb atoms with a frequency-modulated control laser and discuss its application in multichannel and multifrequency light memory.

Wei Xiaogang [Department of Physics, Florida International University, Miami, Florida 33199 (United States); College of Physics, Jilin University, Changchun 130023 (China); Wang Yanhua [Department of Physics, Florida International University, Miami, Florida 33199 (United States); College of Physics and Electronics, Shanxi University, Taiyuan 030006 (China); Zhang Jiepeng [Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Physics Division P-23, Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States); Zhu Yifu [Department of Physics, Florida International University, Miami, Florida 33199 (United States)

2011-10-15

264

Ultrarelativistic electromagnetic pulses in plasmas  

SciTech Connect

We study through computer simulation the physical processes of a linearly polarized electromagnetic pulse of highly relativistic amplitude (eE/m..omega..c>>1) in an underdense plasma accelerating particles to very high energies. We consider first an electron-positron plasma. The maximum momenta achieved scale as the square of the wave amplitude. This acceleration stops when the bulk of the wave energy is converted to particle energy. The pulse leaves behind as a wake a vacuum region whose length scales as the amplitude of the wave. The results can be explained in terms of a snow plow or pistonlike action of the radiation on the plasma. When a mass ratio other than unity is chosen and electrostatic effects begin to play a role, first the ion energy increases faster than the electron energy and then the electron energy catches up later, eventually reaching the same value.

Ashour-Abdalla, M.; Leboeuf, J.N.; Tajima, T.; Dawson, J.M.; Kennel, C.F.

1981-04-01

265

Mechanics background influences students' conceptions in electromagnetism  

NSDL National Science Digital Library

The understanding of different aspects of the 'field' concept in electromagnetism was tested with high school students and prospective teachers of technological disciplines. Some of the observed difficulties could be interpreted as originating from the change in methodological approaches employed in different domains of physics: electromagnetism vis-a-vis mechanics. This may have encouraged students to misinterpret the nature of force interactions and work-energy conversions in the presence of electromagnetic fields. Clarification of the rationale for introducing the 'field' concept, especially in its historical aspect, could be useful in coping with the teaching-learning problems evidenced in this study and other research.

Galili, Igal

2006-05-08

266

Varying electromagnetic coupling and primordial magnetic fields  

SciTech Connect

We study the effect of variations of the electromagnetic coupling on the process of generation of primordial magnetic fields. We find that only through a significant growth of the electromagnetic coupling can minimum seed fields be produced. We also show that, if through some process in the early Universe the photon acquires a mass that leads, thanks to inflation, to the generation of primordial magnetic fields, then the influence of variations of the electromagnetic coupling amounts essentially to the results due to the photon effective mass alone.

Bertolami, O.; Monteiro, R. [Departamento de Fisica, Instituto Superior Tecnico, Av. Rovisco Pais 1, 1049-001 Lisbon (Portugal)

2005-06-15

267

Electromagnetic characterization of metallic sensory alloy  

NASA Astrophysics Data System (ADS)

Ferromagnetic shape-memory alloy (FSMA) particles undergo changes in both electromagnetic properties and crystallographic structure when strained. When embedded in a structural material, these attributes can provide sensory output of the strain state of the structure. In this work, a detailed characterization of the electromagnetic properties of a FSMA under development for sensory applications is performed. In addition, a new eddy current probe is used to interrogate the electromagnetic properties of individual FSMA particles embedded in the sensory alloy during controlled fatigue tests on the multifunctional material.

Wincheski, Buzz; Simpson, John; Wallace, Terryl; Newman, Andy; Leser, Paul; Lahue, Rob

2013-01-01

268

Disciplinary knots and learning problems in electromagnetism  

NASA Astrophysics Data System (ADS)

The concept of field acquire the ontological status of a physical entity when we consider dynamic situations. In this context rise up typical disciplinary knots that are source of learning problems for students, connected to: the sources of time depending fields, the electrodynamic of moving conductors, the nature of electric and magnetic fields as components of the electromagnetic field. A discussion of these principal knots on electromagnetism, and an analysis of the related learning problems provide one of the tree vertex of the triangle founding a research aimed to design a teaching/learning path on electromagnetic field.

Stefanel, Alberto

2008-05-01

269

Perfect Electromagnetic Conductor as Building Block for Complex Materials  

Microsoft Academic Search

This article analyzes how the perfect electromagnetic conductor (PEMC) can be used as a component phase in complex material composites. The recently introduced PEMC concept connects the fullest isotropy with complex and nonintuitive material effects in electromagnetics. The electromagnetic response of such PEMC material obeys the constitutive equation relating the electromagnetic two-forms (in the four-dimensional formulation) by a scalar factor.

A. Sihvola; I. V. Lindell

2006-01-01

270

Electromagnetic field radiation model for lightning strokes to tall structures  

Microsoft Academic Search

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

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

1996-01-01

271

An Efficient Algorithm for Shielding Electromagnetic Topological Diagram  

Microsoft Academic Search

An electromagnetic topology method used to analyze interactions between electronic systems and electromagnetic environment is presented. Combining electromagnetic topology model with the graph theory, an efficient algorithm is obtained. The algorithm can find out all the paths which have a lower shielding coefficient than the given threshold K in the shielding electromagnetic topological diagram.

Yongfeng Wang; Chengda Yu; Chaowei Zhang

2010-01-01

272

Introduction of an Electromagnetism Module in LS-DYNA for Coupled Mechanical-Thermal-Electromagnetic Simulations  

Microsoft Academic Search

A new electromagnetism module is being developed in LD-DYNA for coupled mechanical\\/thermal\\/electromagnetic simulations. One of the main applications of this module is Electromagnetic Metal Forming. The physics, numerical methods and capabilities of this new module are briefly presented. This module is then illustrated on different simulations. A first set of simulations corresponds to a ring expansion experiment, which was performed

Pierre L'Eplattenier; Grant Cook; Cleve Ashcraft; Mike Burger; Art Shapiro; Glenn Daehn; Mala Seth

273

Nonlocal theory of electromagnetic wave decay into two electromagnetic waves in a rippled density plasma channel  

SciTech Connect

Parametric decay of a large amplitude electromagnetic wave into two electromagnetic modes in a rippled density plasma channel is investigated. The channel is taken to possess step density profile besides a density ripple of axial wave vector. The density ripple accounts for the momentum mismatch between the interacting waves and facilitates nonlinear coupling. For a given pump wave frequency, the requisite ripple wave number varies only a little w.r.t. the frequency of the low frequency decay wave. The radial localization of electromagnetic wave reduces the growth rate of the parametric instability. The growth rate decreases with the frequency of low frequency electromagnetic wave.

Sati, Priti; Tripathi, V. K. [Indian Institute of Technology, Hauz Khas, Delhi 110054 (India)

2012-12-15

274

Electromagnetic Pulse and the Electric Power Network.  

National Technical Information Service (NTIS)

This paper defines the nuclear electromagnetic pulse (EMP) - electric power system interaction problem. A description of high altitude EMP (HEMP) characteristics, source region EMP (SREMP) characteristics, and magnetohydrodynamics EMP (MHD-EMP) characteri...

K. W. Klein P. R. Barnes H. W. Zaininger

1984-01-01

275

Electromagnetic ion/ion cyclotron instability  

SciTech Connect

Linear analysis and hybrid simulations are used to investigate the properties of a new electromagnetic ion beam instability. Some applications of the instability in space are also discussed. 7 refs., 1 fig.

Winske, D.; McKean, M.E. (Los Alamos National Lab., NM (USA)); Omidi, N.; Chou, V. (California Univ., San Diego, CA (USA))

1991-01-01

276

Tabletop Models for Electrical and Electromagnetic Geophysics.  

ERIC Educational Resources Information Center

Details the use of tabletop models that demonstrate concepts in direct current electrical resistivity, self-potential, and electromagnetic geophysical models. Explains how data profiles of the models are obtained. (DDR)

Young, Charles T.

2002-01-01

277

Large gap control in electromagnetic levitation.  

PubMed

This paper describes design and implementation of a single axis dc attraction type electromagnetic suspension system where an electromagnet of 2.6 kg mass is levitated over a large gap under a fixed ferromagnetic guide-way. The electromagnet exhibits nonlinear force-current-distance characteristics, and if controllers are to be designed by using linear analysis, the air-gap is restricted to a small region around the chosen nominal operating point. In this work, an attempt has been made to increase the operating range of an electromagnetic suspension system by using the concept of piecewise linear control where the nonlinear force-current-airgap relationships of the magnetic suspension system have been successively linearized at several operating points with a suitable controller designed for each operating point. A novel analog switching scheme has been designed and implemented to automatically switch to the relevant controller depending on the actual air-gap. PMID:16649567

Banerjee, Subrata; Prasad, Dinkar; Pal, Jayanta

2006-04-01

278

Management: Army Management of the Electromagnetic Spectrum.  

National Technical Information Service (NTIS)

This revision updates and consolidates several regulations regarding policies and responsibilities for Army management of the electromagnetic spectrum. It covers the coordination and integration of the research, development, test, acquisition, fielding an...

1997-01-01

279

Clay Seam Mapping With Electromagnetic Induction.  

National Technical Information Service (NTIS)

This report summarizes multi-phase geophysical demonstrations using various electromagnetic induction (EMI) methods on SR-537 near Dulce, New Mexico. The road has had extensive surface rehabilitation due to the presence of swelling clay-rich zones in the ...

J. Pfeiffer K. Hanna

2005-01-01

280

Electromagnetic Properties of the Higgs Vacuum.  

National Technical Information Service (NTIS)

Introducing a lattice equivalent of a current coupling to the gauge potential, we study various abelian Higgs models in the background of constant external electromagnetic field strength tensors. As expected from the analogy to superconductivity in terms ...

P. H. Damgaard U. M. Heller

1988-01-01

281

Printed Wiring Board for Shielding Electromagnetic Waves.  

National Technical Information Service (NTIS)

Recently, undesired radiation of electromagnetic waves from electronic devices has become a serious problem as the signal speed is increased. For the conventional measures, circuit pattern design, selection of components, shielding, grounding and wiring h...

H. Haniu S. Kubota T. Takatsuji H. Higuchi M. Takamatsu

1989-01-01

282

Tour of the Electromagnetic Spectrum Booklet  

NSDL National Science Digital Library

This booklet introduces electromagnetic waves, their behaviors, and how scientists visualize these data. Each region of the spectrum is described and illustrated with examples of NASA science. It is a companion piece to the video series under the same title.

Benesch, Troy

2010-01-01

283

Electromagnetic Propulsion: Drag and Erosion Modeling.  

National Technical Information Service (NTIS)

Railgun electromagnetic accelerators are currently being designed for hypervelocity projectile launch in equation of state impact experiments. Launcher development is proceeding in successive stages of increased acceleration and velocity with a goal of la...

A. C. Buckingham

1980-01-01

284

Electromagnetic ''Particle-in-Cell'' Plasma Simulation.  

National Technical Information Service (NTIS)

''PIC'' simulation tracks particles through electromagnetic fields calculated self-consistently from the charge and current densities of the particles themselves, external sources, and boundaries. Already used extensively in plasma physics, such simulatio...

A. B. Langdon

1985-01-01

285

Electromagnetic channel capacity for practical purposes  

NASA Astrophysics Data System (ADS)

What is the maximum rate at which digital information can be communicated without error using electromagnetic signals, such as radio communication? According to Shannon theory this rate is the capacity of the communication channel, which is obtained by maximizing the mutual information between the channel's input and output. Shannon theory, however, has been developed within classical physics, whereas electromagnetic signals are, ultimately, quantum-mechanical entities. To account for this fact, the capacity must be expressed in terms of a complicated optimization of the Holevo information, but explicit solutions are still unknown for arguably the most elementary electromagnetic channel, the one degraded by additive thermal noise. We place bounds on the thermal channel's Holevo information that determine the capacity up to corrections that are insignificant for practical scenarios such as those with high noise or low transmissivity. Our results apply to any bosonic thermal-noise channel, including electromagnetic signalling at any frequency.

Giovannetti, Vittorio; Lloyd, Seth; Maccone, Lorenzo; Shapiro, Jeffrey H.

2013-10-01

286

EMC (Electromagnetic Compatibility) Standard for Medical Devices.  

National Technical Information Service (NTIS)

The report fulfills requirements of FDA Contract 223-74-5246 to research, evaluate, and document performance parameters and methods of test for use in an electromagnetic compatibility (EMC) standard for medical devices. The objectives were met by performi...

1976-01-01

287

Electrical wire insulation and electromagnetic coil  

DOEpatents

An electromagnetic coil for high temperature and high radiation application in which glass is used to insulate the electrical wire. A process for applying the insulation to the wire is disclosed which results in improved insulation properties.

Bich, George J. (Penn Hills, PA); Gupta, Tapan K. (Monroeville, PA)

1984-01-01

288

Electromagnetic Absorption Effects in Plasma Spheres.  

National Technical Information Service (NTIS)

A set of equations is developed describing the steady state thermodynamics of a homogeneous plasma sphere for electromagnetic plane wave absorption in the case of electric dipole absorption resonance. The thermodynamic properties of the system are obtaine...

N. E. Pedersen J. Davis

1964-01-01

289

Electromagnetics Division Programs Activities, and Accomplishments.  

National Technical Information Service (NTIS)

The Electromagnetics Division is a critical national resource for a wide range of customers. U.S. industry is the primary customer both for the division's measurement services and for technical support on the test and measurement methodology necessary for...

2005-01-01

290

Advanced Electromagnetic Methods for Aerospace Vehicles.  

National Technical Information Service (NTIS)

The Advanced Helicopter Electromagnetics (AHE) Industrial Associates Program has fruitfully completed its fourth year. Under the support of the AHE members and the joint effort of the research team, new and significant progress has been achieved in the ye...

C. A. Balanis W. Sun E. El-sharawy J. T. Aberle C. R. Birtcher

1993-01-01

291

Electromagnetic Wave Propagation in Periodic Media.  

National Technical Information Service (NTIS)

The study investigates the propagation of electromagnetic waves in a rectangular waveguide which contains a periodically varying unidirectionally inhomogeneous medium. Variations of both permittivity and permeability in the direction of propagation are co...

R. M. Hall

1974-01-01

292

SP-100 thermoelectric-electromagnetic pump review  

SciTech Connect

This report contains vugraphs of a presentation on thermoelectric-electromagnetic pumps. It contains: engineering drawings; summary of rectangular TEMP results and comparison with GE predictions; and results of optimization study.

NONE

1988-12-31

293

Alternative Labelling Schemes in Electromagnetic Topology.  

National Technical Information Service (NTIS)

This report defines the problems associated with applying graph theory to interaction sequence diagrams used in electromagnetic topology. Because few applications have been developed, the optimal labelling scheme has yet to emerge. As a result, operations...

R. S. Noss

1983-01-01

294

Effects of Coherence in Electromagnetic Radiation.  

National Technical Information Service (NTIS)

The report summarizes researches concerned with theoretical studies of coherence effects in electromagnetic fields, with special reference to the electromangetic range of the spectrum. Various properties of fluctuating fields were investigated and second ...

E. Wolf

1967-01-01

295

Bioelectromagnetic effects of the electromagnetic pulse (EMP)  

Microsoft Academic Search

The public has expressed concern about the biological effects and hazards of non-ionizing electromagnetic fields produced by the electro-magnetic pulse (EMP) simulators that simulate the EMP emanating from a high-altitude nuclear explosion. This paper provides a summary of the bioelectromagnetic effects literature up through the present, describes current occupational standards for workers exposed to the EMP environment, and discusses the

E. L. Patrick; W. L. Vault

1990-01-01

296

Electromagnetic Transport from Microtearing Mode Turbulence  

SciTech Connect

This Letter presents nonlinear gyrokinetic simulations of microtearing mode turbulence. The simulations include collisional and electromagnetic effects and use experimental parameters from a high-{beta} discharge in the National Spherical Torus Experiment. The predicted electron thermal transport is comparable to that given by experimental analysis, and it is dominated by the electromagnetic contribution of electrons free-streaming along the resulting stochastic magnetic field line trajectories. Experimental values of flow shear can significantly reduce the predicted transport.

Guttenfelder, W.; Kaye, S. M.; Bell, R. E.; Hammett, G. W.; LeBlanc, B. P.; Mikkelsen, D. R. [Princeton Plasma Physics Laboratory, Princeton New Jersey 08543 (United States); Candy, J. [General Atomics, San Diego, California 92186 (United States); Nevins, W. M.; Wang, E. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Yuh, H. [Nova Photonics Inc., Princeton, New Jersey 08540 (United States)

2011-04-15

297

Modeling semi-anechoic electromagnetic measurement chambers  

Microsoft Academic Search

Previous studies developed a model to predict theoretically the low-frequency plane-wave reflection coefficient of an array of pyramid cone absorbers such as those used to line anechoic electromagnetic measurement chambers. The present authors apply this model in a geometrical optics approach to predict the electromagnetic field in a chamber lined with cone absorbers in the frequency range of 30-300 MHz.

Christopher L. Holloway; Edward F. Kuester

1996-01-01

298

Electromagnetic Transport From Microtearing Mode Turbulence  

SciTech Connect

This Letter presents non-linear gyrokinetic simulations of microtearing mode turbulence. The simulations include collisional and electromagnetic effects and use experimental parameters from a high beta discharge in the National Spherical Torus Experiment (NSTX). The predicted electron thermal transport is comparable to that given by experimental analysis, and it is dominated by the electromagnetic contribution of electrons free streaming along the resulting stochastic magnetic field line trajectories. Experimental values of flow shear can significantly reduce the predicted transport.

Guttenfelder, W; Kaye, S M; Nevins, W M; Wang, E; Bell, R E; Hammett, G W; LeBlanc, B P; Mikkelsen, D R

2011-03-23

299

Electromagnetic compatability 1982. Parts 1 & 2  

NASA Astrophysics Data System (ADS)

The origin, effect, measurement, and control of electromagnetic influences on biological and technological systems are discussed in reports and reviews. Subject areas addressed include electromagnetic compatibility (EMC) and space technology, EMC theory and models, switching and discharge noise sources, antennas, EM fields and propagation, radio communication, immunity, wire communication, lightning, and EMC in power systems. Sections are also devoted to specific noise sources and filters, measurement technology, and EMC and biology.

Bem, D. J.; Moron, W.; Struzak, R. G.

300

Electromagnetic Radiation System (EMRS) for susceptibility testing  

NASA Astrophysics Data System (ADS)

The Electromagnetic Radiation System (EMRS) is designed to generate electromagnetic energy to produce a constant field strength while scanned automatically in frequency. Design objective was 200 volts per meter from 30 Hz to 40 GHz. This report describes the development of prototype system elements covering the ranges of 30-60 MHz, 1-2.1 GHz, 2.1-4.0 GHz and 12.4-18.0 GHz.

Arsdale, J. V.

1981-06-01

301

Quasi-Gaussian electromagnetic beams  

NASA Astrophysics Data System (ADS)

A class of Maxwellian beams, which is an exact solution of the vector wave equation (Helmholtz equation) and Maxwell's equations, is introduced. The solution, termed a quasi-Gaussian electromagnetic (EM) beam, is formed from a superposition of sources and sinks with complex coordinates, and is characterized by an arbitrary waist w0 and a diffraction convergence length known as the Rayleigh range zR. An attractive feature of this beam is the description of strongly focused (or strongly divergent) EM-optical wave fields for kw0?1, where k is the wave number. A vector wave analysis is developed to determine and compute the spatial Cartesian components of the electric and magnetic fields (valid in the near field and the far field) stemming from Maxwell's vector equations and the Lorenz gauge condition, with particular emphasis on the parameter kw0 and the polarization states of the vector potentials used to derive the EM field's components. The results are potentially useful in the study of the axial and/or arbitrary wave scattering, radiation force, and torque in lasers operating with strongly focused (or strongly divergent) beams for particle manipulation in optical tweezers and imaging applications.

Mitri, F. G.

2013-03-01

302

Electromagnetic momentum conservation in media  

NASA Astrophysics Data System (ADS)

That static electric and magnetic fields can store momentum may be perplexing, but is necessary to ensure total conservation of momentum. Simple situations in which such field momentum is transferred to nearby bodies and point charges have often been considered for pedagogical purposes, normally assuming vacuum surroundings. If dielectric media are involved, however, the analysis becomes more delicate, not least since one encounters the electromagnetic energy-momentum problem in matter, the 'Abraham-Minkowski enigma', of what the momentum is of a photon in matter. We analyze the momentum balance in three nontrivial examples obeying azimuthal symmetry, showing how the momentum conservation is satisfied as the magnetic field decays and momentum is transferred to bodies present. In the last of the examples, that of point charge outside a dielectric sphere in an infinite magnetic field, we find that not all of the field momentum is transferred to the nearby bodies; a part of the momentum appears to vanish as momentum flux towards infinity. We discuss this and other surprising observations which can be attributed to the assumption of magnetic fields of infinite extent. We emphasize how formal arguments of conserved quantities cannot determine which energy-momentum tensor is more "correct", and each of our conservation checks may be performed equally well in the Minkowski or Abraham framework.

Brevik, Iver; Ellingsen, Simen Å.

2011-03-01

303

Electromagnetic momentum conservation in media  

SciTech Connect

That static electric and magnetic fields can store momentum may be perplexing, but is necessary to ensure total conservation of momentum. Simple situations in which such field momentum is transferred to nearby bodies and point charges have often been considered for pedagogical purposes, normally assuming vacuum surroundings. If dielectric media are involved, however, the analysis becomes more delicate, not least since one encounters the electromagnetic energy-momentum problem in matter, the 'Abraham-Minkowski enigma', of what the momentum is of a photon in matter. We analyze the momentum balance in three nontrivial examples obeying azimuthal symmetry, showing how the momentum conservation is satisfied as the magnetic field decays and momentum is transferred to bodies present. In the last of the examples, that of point charge outside a dielectric sphere in an infinite magnetic field, we find that not all of the field momentum is transferred to the nearby bodies; a part of the momentum appears to vanish as momentum flux towards infinity. We discuss this and other surprising observations which can be attributed to the assumption of magnetic fields of infinite extent. We emphasize how formal arguments of conserved quantities cannot determine which energy-momentum tensor is more 'correct', and each of our conservation checks may be performed equally well in the Minkowski or Abraham framework.

Brevik, Iver [Department of Energy and Process Engineering, Norwegian University of Science and Technology, N-7491 Trondheim (Norway); Ellingsen, Simen A., E-mail: simen.a.ellingsen@ntnu.no [Department of Energy and Process Engineering, Norwegian University of Science and Technology, N-7491 Trondheim (Norway)

2011-03-15

304

Advances in electromagnetic brain imaging  

NASA Astrophysics Data System (ADS)

Non-invasive and dynamic imaging of brain activity in the sub-millisecond time-scale is enabled by measurements on or near the scalp surface using an array of sensors that measure magnetic fields (magnetoencephalography (MEG)) or electric potentials (electroencephalography (EEG)). Algorithmic reconstruction of brain activity from MEG and EEG data is referred to as electromagnetic brain imaging (EBI). Reconstructing the actual brain response to external events and distinguishing unrelated brain activity has been a challenge for many existing algorithms in this field. Furthermore, even under conditions where there is very little interference, accurately determining the spatial locations and timing of brain sources from MEG and EEG data is challenging problem because it involves solving for unknown brain activity across thousands of voxels from just a few sensors (~300). In recent years, my research group has developed a suite of novel and powerful algorithms for EBI that we have shown to be considerably superior to existing benchmark algorithms. Specifically, these algorithms can solve for many brain sources, including sources located far from the sensors, in the presence of large interference from unrelated brain sources. Our algorithms efficiently model interference contributions to sensors, accurately estimate sparse brain source activity using fast and robust probabilistic inference techniques. Here, we review some of these algorithms and illustrate their performance in simulations and real MEG/EEG data.

Nagarajan, Srikantan S.

2010-02-01

305

Medical applications of electromagnetic fields  

NASA Astrophysics Data System (ADS)

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.

Lai, Henry C.; Singh, Narendra P.

2010-04-01

306

Inertia, Electromagnetism and Fluid Dynamics  

NASA Astrophysics Data System (ADS)

It is shown that the vector potential created by a charged particle in motion acts as an ideal space flow that surrounds the particle. The interaction between the particle and the entrained space flow gives rise to the observed properties of inertia and the relativistic increase of mass. Parallels are made between the inertia property of matter, electromagnetism and the hydrodynamic drag in potential flow. Accordingly, in this framework the non resistance of a particle in uniform motion through an ideal fluid (Paradox of Dirichlet) corresponds to Newton's first law. The law of inertia suggests that the physical vacuum can be modeled as an ideal fluid. It is shown that the force exerted on a particle by an ideal fluid produces two effects: i) resistance to acceleration and, ii) an increase of mass with velocity which is due to the fluid dragged by the particle, where the bare mass of the particle at rest changes when in motion (``dressed'' particle). From this theoretical ground, the inertia property of matter appears in a new light representing a promising avenue to create new propulsion concepts.

Martins, Alexandre A.; Pinheiro, Mario J.

2008-01-01

307

Electromagnetic antenna modeling (EAM) system  

NASA Astrophysics Data System (ADS)

The determination of foreign communications capabilities and intent is an important assessment function performed by the USAF National Air Intelligence Center (NAIC). In this context, Rome Laboratory became the NAIC engineering agent for the development of an NAIC requirement for the rapid analysis and evaluation of antenna structures based on often vague to sometimes detailed dimensional information. To this end, the Rome Laboratory sponsored development of the Electromagnetic Antenna Modeling (EAM) System, a state-of-the-art Pascal program with an MS Windows graphical user interface (GUI) pre- and post-processor. Users of NAIC capabilities initiate antenna analysis efforts that range from simple parametric studies to more complex, detailed antenna design and communication-system evaluations. Accordingly, EAM provides a modeling capability 'matched' to the sophistication of the individual analyst, with features appropriate for users ranging from nontechnical analysts to experienced antenna engineers. This capability is particularly valuable in the military-intelligence environment, in which high-speed assessments are required. In particular, EAM meets the specific antenna-analysis requirements of NAIC with a versatile graphical user interface.

Packer, Malcolm; Powers, Robert; Tsitsopoulos, Paul

1994-12-01

308

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

Microsoft Academic Search

Electromagnetic interference (EMI) is a source of noise problems in electronic devices. The EMI is attributed to coupling between sources of radiation and components placed in the same media such as package or chassis. This coupling can be either through conducting currents or through radiation. The radiation of electromagnetic (EM) fields is supported by surface currents. Thus, minimizing these surface

Baharak Mohajer Iravani

2007-01-01

309

An Electromagnetic Topology and Transmission Line Matrix Hybrid Technique for Modeling High Power Electromagnetic Interactions  

Microsoft Academic Search

A combination of electromagnetic topology (EMT) and a transmission line matrix methodology to simulate an external electromagnetic pulse's interactions with cable network following penetration through apertures is presented. The results show improvements over previous simulations using EMT technique only. An array of the topological network has been created by the integration of the sub-network matrices based on the transmission line

Phumin Kirawanich; David Gleason; N. E. Islam

2005-01-01

310

Electromagnetic topology analysis on relation between electromagnetic interference inside equipment and external electrostatic discharge  

Microsoft Academic Search

Simulation based on electromagnetic topology theory was applied to analyze the relationship between internal electromagnetic interference (EMI) and external electrostatic discharge (ESD) of semi-shielded electrical equipment. The topological structure model of the equipment was built to analyze the coupling paths of external disturbance. To the aperture coupling path, a new method was adopted to determine the transfer function between external

Bo Niu; Zhengxiang Song; Yingsan Geng; Jianhua Wang; Jing Wang

2008-01-01

311

Detector for electromagnetic radiation and a method of detecting electromagnetic radiation  

US Patent & Trademark Office Database

A detector for detecting electromagnetic radiation, especially for electromagnetic radiation in the GHz or THz range. The detector comprises a semiconductor structure having a 2D charge carrier layer or a quasi 2D charge carrier layer with an edge, at least first and second contacts to said charge carrier layer, said contacts being provided at said edge and being spaced apart by a distance, and a device for measuring at least one of the photocurrent between said first and second contacts, the photovoltage between said first and second contacts and the resistance between said first and second contacts. A device is provided for applying a magnetic field to said detector with a field component perpendicular to said charge carrier layer. An output signal of said measuring device provides information about at least one of the presence of electromagnetic radiation, the intensity of the incident electromagnetic radiation and the frequency of the incident electromagnetic radiation.

2006-01-17

312

Building health: The need for electromagnetic hygiene?  

NASA Astrophysics Data System (ADS)

Whilst the electromagnetic nature of the built environment has changed considerably over the past century, little thought is at present given to the possible advantages of creating electromagnetic microenvironments that more closely resemble those found in nature and/or developing biologically-friendly technology aligned more closely to its operating principles. This review paper examines how more natural exposures to a variety of electromagnetic phenomena could be re-introduced into the built environment, possible benefits that might arise, and discusses the extent to which there may be tangible benefits obtainable from introducing more rigorous properly considered electromagnetic hygiene measures. Amongst the matters discussed are: the effects of different materials, finishes and electrical items on charge generation (and the effects of excess charge on contaminant deposition); the possible benefits of suitably grounding conductive objects (including humans) in order to reduce excess charge and contaminant deposition; how the presence of vertical electric field regimes, similar to those found in nature, may enhance biological performance; and possible pitfalls to avoid when seeking to introduce appropriate electromagnetic hygiene regimes.

Jamieson, Isaac A.; Holdstock, Paul; ApSimon, Helen M.; Bell, J. Nigel B.

2010-04-01

313

Magnetic flimmers: 'light in the electromagnetic darkness'.  

PubMed

Transcranial magnetic stimulation has become an important field for both research in neuroscience and for therapy since Barker in 1985 showed that it was possible to stimulate the human motor cortex with an electromagnet. Today for instance, transcranial magnetic stimulation can be used to measure nerve conduction velocities and to create virtual lesions in the brain. The latter option creates the possibility to inactivate parts of the brain temporarily without permanent damage. In 2008, the American Food and Drugs Administration approved repetitive transcranial magnetic stimulation as a therapy for major depression under strict conditions. Repetitive transcranial magnetic stimulation has not yet been cleared for treatment of other diseases, including schizophrenia, anxiety disorders, obesity and Parkinson's disease, but results seem promising. Transcranial magnetic stimulation, however, was not invented at the end of the 20th century. The discovery of electromagnetism, the enthusiasm for electricity and electrotherapy, and the interest in Beard's concept of neurasthenia already resulted in the first electromagnetic treatments in the late 19th and early 20th century. In this article, we provide a history of electromagnetic stimulation circa 1900. From the data, we conclude that Mesmer's late 18th century ideas of 'animal magnetism' and the 19th century absence of physiological proof had a negative influence on the acceptance of this therapy during the first decades of the 20th century. Electromagnetism disappeared from neurological textbooks in the early 20th century to recur at the end of that century. PMID:23043145

Martens, Johannes W; Koehler, Peter J; Vijselaar, Joost

2012-10-05

314

Electromagnetic energy momentum in dispersive media  

SciTech Connect

The standard derivations of electromagnetic energy and momentum in media take Maxwell's equations as the starting point. It is well known that for dispersive media this approach does not directly yield exact expressions for the energy and momentum densities. Although Maxwell's equations fully describe electromagnetic fields, the general approach to conserved quantities in field theory is not based on the field equations, but rather on the action. Here an action principle for macroscopic electromagnetism in dispersive, lossless media is used to derive the exact conserved energy-momentum tensor. The time-averaged energy density reduces to Brillouin's simple formula when the fields are monochromatic. The time-averaged momentum density for monochromatic fields corresponds to the familiar Minkowski expression DxB, but for general fields in dispersive media the momentum density does not have the Minkowski value. The results are unaffected by the debate over momentum balance in light-matter interactions.

Philbin, T. G. [School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9SS, Scotland (United Kingdom)

2011-01-15

315

Broadband electromagnetic cloaking with smart metamaterials  

NASA Astrophysics Data System (ADS)

The ability to render objects invisible with a cloak that fits all objects and sizes is a long-standing goal for optical devices. Invisibility devices demonstrated so far typically comprise a rigid structure wrapped around an object to which it is fitted. Here we demonstrate smart metamaterial cloaking, wherein the metamaterial device not only transforms electromagnetic fields to make an object invisible, but also acquires its properties automatically from its own elastic deformation. The demonstrated device is a ground-plane microwave cloak composed of an elastic metamaterial with a broad operational band (10-12?GHz) and nearly lossless electromagnetic properties. The metamaterial is uniform, or perfectly periodic, in its undeformed state and acquires the necessary gradient-index profile, mimicking a quasi-conformal transformation, naturally from a boundary load. This easy-to-fabricate hybrid elasto-electromagnetic metamaterial opens the door to implementations of a variety of transformation optics devices based on quasi-conformal maps.

Shin, Dongheok; Urzhumov, Yaroslav; Jung, Youngjean; Kang, Gumin; Baek, Seunghwa; Choi, Minjung; Park, Haesung; Kim, Kyoungsik; Smith, David R.

2012-11-01

316

Electromagnetic radiation field of an electron avalanche  

NASA Astrophysics Data System (ADS)

Electron avalanches are the main constituent of electrical discharges in the atmosphere. However, the electromagnetic radiation field generated by a single electron avalanche growing in different field configurations has not yet been evaluated in the literature. In this paper, the electromagnetic radiation fields created by electron avalanches were evaluated for electric fields in pointed, co-axial and spherical geometries. The results show that the radiation field has a duration of approximately 1-2 ns, with a rise time in the range of 0.25 ns. The wave-shape takes the form of an initial peak followed by an overshoot in the opposite direction. The electromagnetic spectrum generated by the avalanches has a peak around 109 Hz.

Cooray, Vernon; Cooray, Gerald

2012-11-01

317

Feedback Control for Electromagnetic Vibration Feeder  

NASA Astrophysics Data System (ADS)

An electromagnetic-type vibratory feeder of is a typical transportation device used in automatic weighers. As existing feeders are driven by feedforward control, the so-called “firing angle control”, the driver cannot negate sudden disturbances. In this study, we consider applying a feedback control for such a feeder system. First, we give the two details of modelings for the vibration part and for the electromagnetic force part. Next, a feedback control system is constructed for the electromagnetic vibration feeder for which we propose a two-degrees-of-freedom proportional plus integral plus derivative (PID) controller with nonlinear elements. Next, we apply the feedback control to the feeder with a standard trough. Finally, we consider a method compatible with many varieties of troughs by adjusting a nonlinear element. On the basis of the results of some experiments, we confirm that the two-degrees-of-freedom PID control is more effective than the conventional firing angle control.

Doi, Tomoharu; Yoshida, Koji; Tamai, Yutaka; Kono, Katsuaki; Naito, Kazufumi; Ono, Toshiro

318

Parameter estimation from noisy transient electromagnetic measurements  

SciTech Connect

The study of the EMP phenomenon has promoted the development of techniques to investigate transient electromagnetic response data. Characterization of the EMP transient response information is necessary to evaluate the performance of that system in a hostile environment. An efficient technique to characterize this performance is to fit an electromagnetic model to the data. The performance of three different signal processing techniques applied to parameterize a body from noisy experimental electromagnetic transient response data is described. The techniques, which range from the well-known Prony method to the more sophisticated extended Kalman filter and finally to the highly sophisticated maximum likelihood identifier, are briefly described. The performance of these algorithms is compared, and their tradeoffs are discussed. 14 figures, 2 tables.

Gavel, D.T.; Candy, J.V.; Lager, D.L.

1980-01-01

319

Electromagnetic moments of quasi-stable baryons  

SciTech Connect

We address electromagnetic properties of quasi-stable baryons in the context of chiral extrapolations of lattice QCD results. For particles near their decay threshold we show that an application of a small external magnetic field changes the particle's energy in a non-analytic way. The conventional electromagnetic moments are only well-defined when the background field B satisfies |eB|/2M{sub *}<<|M{sub *}-M-m| where M{sub *} is the mass of the resonance and M, m the masses of the decay products. A direct application of this situation is the chiral extrapolation of the {Delta}(1232)-isobar electromagnetic properties. We discuss such an extrapolation of the {Delta}(1232)-isobar magnetic dipole, electric quadrupole and magnetic octupole moments by a covariant chiral effective field theory.

Ledwig, T.; Pascalutsa, V.; Vanderhaeghen, M. [Institut fuer Kernphysik, Universitaet Mainz, D-55099 Mainz (Germany); Martin-Camalich, J. [Departamento de Fisica Teorica and IFIC, Universidad de Valencia-CSIC (Spain)

2011-10-24

320

Electromagnetically driven dwarf tornados in turbulent convection  

NASA Astrophysics Data System (ADS)

Motivated by the concept of interdependency of turbulent flow and electromagnetic fields inside the spiraling galaxies, we explored the possibilities of generating a localized Lorentz force that will produce a three-dimensional swirling flow in weakly conductive fluids. Multiple vortical flow patterns were generated by combining arrays of permanent magnets and electrodes with supplied dc current. This concept was numerically simulated and applied to affect natural convection flow, turbulence, and heat transfer inside a rectangular enclosure heated from below and cooled from above over a range of Rayleigh numbers (104<=Ra<=5×109). The large-eddy simulations revealed that for low- and intermediate-values of Ra, the heat transfer was increased more than five times when an electromagnetic forcing was activated. In contrast to the generally accepted view that electromagnetic forcing will suppress velocity fluctuations and will increase anisotropy of turbulence, we demonstrated that localized forcing can enhance turbulence isotropy of thermal convection compared to its neutral state.

Kenjereš, Saša

2011-01-01

321

Electromagnetically induced absorption via incoherent collisions  

SciTech Connect

We conduct theoretical studies on electromagnetically induced absorption via incoherent collisions in an inhomogeneously broadened ladder-type three-level system with the density-matrix approach. The effects of the collision-induced coherence decay rates as well as the probe laser field intensity on the probe field absorption are examined. It is shown that with the increase of the collisional decay rates in a moderate range, a narrow dip due to electromagnetically induced transparency superimposed on the Doppler-broadened absorption background can be turned into a narrow peak under the conditions that the probe field intensity is not very weak as compared to the pump field, which results from the enhancement of constructive interference and suppression of destructive interference between one-photon and multiphoton transition pathways. The physical origin of the collision-assisted electromagnetically induced absorption is analyzed with a power-series solution of the density-matrix equations.

Yang Xihua [Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701 (United States); Department of Physics, Shanghai University, Shanghai 200444 (China); Sheng Jiteng; Xiao Min [Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701 (United States)

2011-10-15

322

Bioelectromagnetic effects of the electromagnetic pulse (EMP)  

SciTech Connect

The public has expressed concern about the biological effects and hazards of non-ionizing electromagnetic fields produced by the electro-magnetic pulse (EMP) simulators that simulate the EMP emanating from a high-altitude nuclear explosion. This paper provides a summary of the bioelectromagnetic effects literature up through the present, describes current occupational standards for workers exposed to the EMP environment, and discusses the use of medical surveillance as it relates to the potential human health hazards associated with exposure to the EMP environment.

Patrick, E.L.; Vault, W.L.

1990-03-01

323

Phenomenology of the deuteron electromagnetic form factors  

SciTech Connect

A rigorous extraction of the deuteron charge form factors from tensor polarization data in elastic electron-deuteron scattering, at given values of the 4-momentum transfer, is presented. Then the world data for elastic electron-deuteron scattering is used to parameterize, in three different ways, the three electromagnetic form factors of the deuteron in the 4-momentum transfer range 0-7 fm. This procedure is made possible with the advent of recent polarization measurements. The parameterizations allow a phenomenological characterization of the deuteron electromagnetic structure. They can be used to remove ambiguities in the form factors extraction from future polarization data.

David Abbott; Abdellah Ahmidouch; H. Anklin; J. Arvieux; James P. Ball; Shelton Beedoe; Elizabeth Beise; Louis Bimbot; Werner Boeglin; Herbert Breuer; Roger Carlini; Nicholas Chant; Samuel Danagoulian; K. Dow; Jean-Eric Ducret; Jim Dunne; Lars Ewell; L. Eyraud; C. Furget; Michel Garcon; Ron Gilman; Charles Glashausser; Paul Gueye; Kenneth Gustafsson; Kawtar Hafidi; A. Honegger; J. Jourdan; Serge Kox; Gerfried Kumbartzki; L. Lu; Allison Lung; Pete Markowitz; Justin McIntyre; David Meekins; F. Merchez; Joseph Mitchell; R. Mohring; S. Mtingwa; H. Mrktchyan; D. Pitz; Liming Qin; Ronald Ransome; J.-S. R'eal; Philip Roos; Paul Rutt; Reyad Sawafta; Stepan Stepanyan; Raphael Tieulent; E. Tomasi-Gustafsson; William Turchinetz; K. Vansyoc; J. Volmer; E. Voutier; Claude Williamson; Stephen Wood; Chen Yan; Jianguo Zhao; W. Zhao

2000-04-01

324

Phenomenology of the deuteron electromagnetic form factors  

SciTech Connect

A rigorous extraction of the deuteron charge form factors from tensor polarization data in elastic electron-deuteron scattering, at given values of the 4-momentum transfer, is presented. Then the world data for elastic electron-deuteron scattering is used to parameterize, in three different ways, the three electromagnetic form factors of the deuteron in the 4-momentum transfer range 0-7 fm. This procedure is made possible with the advent of recent polarization measurements. The parameterizations allow a phenomenological characterization of the deuteron electromagnetic structure. They can be used to remove ambiguities in the form factors extraction from future polarization data.

David Abbott; Abdellah Ahmidouch; H. Anklin; J. Arvieux; James P. Ball; Shelton Beedoe; Elizabeth Beise; Louis Bimbot; Werner Boeglin; Herbert Breuer; Roger Carlini; Nicholas Chant; Samuel Danagoulian; K. Dow; Jean-Eric Ducret; Jim Dunne; Lars Ewell; L. Eyraud; C. Furget; Michel Garcon; Ron Gilman; Charles Glashausser; Paul Gueye; Kenneth Gustafsson; Kawtar Hafidi; A. Honegger; J. Jourdan; Serge Kox; Gerfried Kumbartzki; L. Lu; Allison Lung; Pete Markowitz; Justin McIntyre; David Meekins; F. Merchez; Joseph Mitchell; R. Mohring; S. Mtingwa; H. Mrktchyan; D. Pitz; Liming Qin; Ronald Ransome; J.-S. R'eal; Philip Roos; Paul Rutt; Reyad Sawafta; Stepan Stepanyan; Raphael Tieulent; E. Tomasi-Gustafsson; William Turchinetz; K. Vansyoc; J. Volmer; E. Voutier; Claude Williamson; Stephen Wood; Chen Yan; Jianguo Zhao; W. Zhao

2000-02-25

325

Adjoint shape optimization applied to electromagnetic design.  

PubMed

We present an adjoint-based optimization for electromagnetic design. It embeds commercial Maxwell solvers within a steepest-descent inverse-design optimization algorithm. The adjoint approach calculates shape derivatives at all points in space, but requires only two "forward" simulations. Geometrical shape parameterization is by the level set method. Our adjoint design optimization is applied to a Silicon photonics Y-junction splitter that had previously been investigated by stochastic methods. Owing to the speed of calculating shape derivatives within the adjoint method, convergence is much faster, within a larger design space. This is an extremely efficient method for the design of complex electromagnetic components. PMID:24104043

Lalau-Keraly, Christopher M; Bhargava, Samarth; Miller, Owen D; Yablonovitch, Eli

2013-09-01

326

Electromagnetic stress tensor in ponderable media.  

PubMed

We derive an expression for the Maxwell stress tensor in a magnetic dielectric medium specified by its permittivity epsilon and permeability micro. The derivation proceeds from the generalized form of the Lorentz law, which specifies the force exerted by the electromagnetic E and H fields on the polarization P and magnetization M of a ponderable medium. Our stress tensor differs from the well-known tensors of Abraham and Minkowski, which have been at the center of a century-old controversy surrounding the momentum of the electromagnetic field in transparent materials. PMID:18542621

Mansuripur, Masud

2008-04-14

327

Electromagnetic effects on toroidal momentum transport  

SciTech Connect

A parametric study of electromagnetic effects on toroidal momentum transport has been performed. The work is based on a new version of the Weiland model where symmetry breaking toroidicity effects derived from the stress tensor have been taken into account. The model includes a self-consistent calculation of the toroidal momentum diffusivity, which contains both diagonal and off-diagonal contributions to the momentum flux. It is found that electromagnetic effects considerably increase the toroidal momentum pinch. They are sometimes strong enough to make the total toroidal momentum flux inward.

Mahmood, M. Ansar; Eriksson, A.; Weiland, J. [Department of Radio and Space Science, Chalmers University of Technology, EURATOM/VR Association, SE-41296 Goeteborg (Sweden)

2010-12-15

328

Electromagnetic Interference with Hall Thruster Operation  

NASA Astrophysics Data System (ADS)

The report is concerned with the experience of radio frequency underground testing of Hall plasma thrusters. Both previously published and new experimental data on the generation of microwave oscillations in Hall thrusters are analyzed. The spectra of microwave oscillations and electromagnetic radiation with electron dynamic are determined. The results of ground radio engineering tests on the thruster modules of a combined propulsion unit for Yamal-100 spacecraft are presented and a pulsed electromagnetic radiation component was detected. The experimental data on the amplification of microwave fields by the plasma thruster are presented. The conditions of anomalous microwave fields-plasma interaction are established.

Kirdyashev, K.

2004-10-01

329

Electromagnetically induced transparency for x-rays.  

SciTech Connect

Electromagnetically induced transparency is predicted for x rays in laser-dressed neon gas. The x-ray photoabsorption cross section and polarizability near the Ne K edge are calculated using an ab initio theory suitable for optical strong-field problems. The laser wavelength is tuned close to the transition between 1s-13s and 1s-13p ({approx}800 nm). The minimum laser intensity required to observe electromagnetically induced transparency is of the order of 1012 W/cm2. The ab initio results are discussed in terms of an exactly solvable three-level model. This work opens new opportunities for research with ultrafast x-ray sources.

Buth, C.; Santra, R.; Young, L.; Chemistry

2007-06-22

330

Scanning evanescent electro-magnetic microscope  

DOEpatents

A novel scanning microscope is described that uses near-field evanescent electromagnetic waves to probe sample properties. The novel microscope is capable of high resolution imaging and quantitative measurements of the electrical properties of the sample. The inventive scanning evanescent wave electromagnetic microscope (SEMM) can map dielectric constant, tangent loss, conductivity, complex electrical impedance, and other electrical parameters of materials. The quantitative map corresponds to the imaged detail. The novel microscope can be used to measure electrical properties of both dielectric and electrically conducting materials.

Xiang, Xiao-Dong (Alameda, CA); Gao, Chen (Alameda, CA)

2001-01-01

331

Scanning evanescent electro-magnetic microscope  

DOEpatents

A novel scanning microscope is described that uses near-field evanescent electromagnetic waves to probe sample properties. The novel microscope is capable of high resolution imaging and quantitative measurements of the electrical properties of the sample. The inventive scanning evanescent wave electromagnetic microscope (SEMM) can map dielectric constant, tangent loss, conductivity, complex electrical impedance, and other electrical parameters of materials. The quantitative map corresponds to the imaged detail. The novel microscope can be used to measure electrical properties of both dielectric and electrically conducting materials.

Xiang, Xiao-Dong (Alameda, CA); Gao, Chen (Anhui, CN); Schultz, Peter G. (La Jolla, CA); Wei, Tao (Sunnyvale, CA)

2003-01-01

332

Electromagnetic Gyration Hamiltonian Dynamics of the Stokes Parameters  

Microsoft Academic Search

Starting with a Schrödinger-type equation derived from the Maxwell theory of electromagnetism, a general formalism is presented for the change of light polarization in nonlinear birefringent media, which we call ``optical gyration'' or more generally, ``electromagnetic gyration\\

Hiroshi Kuratsuji; Robert Botet; Ryohei Seto

2007-01-01

333

Characteristics of Electromagnetic Wave Forms with Lightning in Winter Season.  

National Technical Information Service (NTIS)

From measured results of lightning electromagnetic wave forms, the electromagnetic wave forms in winter season were classified, wave propagation under the thunder cloud was clarified and a countermeasure of DF(direction finder) singularity was described. ...

S. Tomita

1988-01-01

334

Nuclear Electromagnetic Pulse and the Electric Power System.  

National Technical Information Service (NTIS)

A single, high-altitude nuclear detonation over the continental United States can expose large geographic areas to transient, electromagnetic pulse (EMP). The initial electromagnetic fields produced by this event have been defined as high-altitude electro...

J. R. Legro T. J. Reed

1985-01-01

335

Simultaneous observation of caviton formation, spiky turbulence, and electromagnetic radiation  

NASA Astrophysics Data System (ADS)

Formation of density cavities, spiky turbulence, and electromagnetic radiation at the plasma frequency and its harmonics are observed simultaneously in the presence of a cold-electron beam. The electrostatic and electromagnetic frequency spectra evolve with the development of cavities.

Cheung, P. Y.; Wong, A. Y.; Darrow, C. B.; Qian, S. J.

1982-05-01

336

Dynamics of ultimately short electromagnetic pulses in chiral carbon nanotubes  

NASA Astrophysics Data System (ADS)

The wave equation for the electromagnetic field propagating in chiral carbon nanotubes has been analyzed. The phenomenological equation similar to the sine-Gordon equation has been derived. The dynamics of the electromagnetic pulse has been investigated.

Konobeeva, N. N.; Belonenko, M. B.

2013-10-01

337

Electromagnetic Pulse Interaction Notes -- EMP 3-38.  

National Technical Information Service (NTIS)

This is a series of five notes on electromagnetic pulse interaction. Subjects covered in this volume are: electromagnetic shielding by advanced composite materials; fields in a rectangular cavity excited by a plane wave on an elliptical aperture; transien...

C. E. Baum

1979-01-01

338

Inhomogeneous cosmological models with electromagnetic field in general relativity  

Microsoft Academic Search

In this paper inhomogeneous cosmological models with perfect fluid distributions in presence of electromagnetic field is obtained. Various physical and geometrical properties of the model in presence of electromagnetic field are also discussed.

Raj Bali; Ghan Shyam Singh

1987-01-01

339

High Selectivity Electromagnetic Bandgap Device and Antenna System.  

National Technical Information Service (NTIS)

An antenna system includes an antenna element and an electromagnetic bandgap element proximate the antenna element wherein the electromagnetic bandgap element is optimized for narrow bandwidth operation thereby providing radiofrequency selectivity to the ...

D. H. Werner M. J. Wilhelm P. L. Werner

2004-01-01

340

Concept of Operation for USACC Electromagnetic Compatibility Program (EMCP).  

National Technical Information Service (NTIS)

The goals of the EMC Program are to: insure efficient integration of engineering, management, and quality assurance tasks, as related to Electromagnetic compatibility (EMC); insure intrasystem and intersystem design and operational electromagnetic compati...

1973-01-01

341

Dynamical evolution of the electromagnetic perturbation with Weyl corrections  

NASA Astrophysics Data System (ADS)

We present firstly the master equation of an electromagnetic perturbation with Weyl correction in the four-dimensional black hole spacetime, which depends not only on the Weyl correction parameter, but also on the parity of the electromagnetic field. It is quite different from that of the usual electromagnetic perturbation without Weyl correction in the four-dimensional spacetime. And then we have investigated numerically the dynamical evolution of the electromagnetic perturbation with Weyl correction in the background of a four-dimensional Schwarzschild black hole spacetime. Our results show that the Weyl correction parameter ? and the parities imprint in the wave dynamics of the electromagnetic perturbation. For the odd parity electromagnetic perturbation, we find it grows with exponential rate if the value of ? is below the negative critical value ?c. However, for the electromagnetic perturbation with even parity, we find that there does not exist such a critical threshold value and the electromagnetic field always decays in the allowed range of ?.

Chen, Songbai; Jing, Jiliang

2013-09-01

342

Skydd mot Elektromagnetiska Stoerningar (Hardening Against Electromagnetic Interference),  

National Technical Information Service (NTIS)

Hardening against Electromagnetic Interference is provided by means of Controlled Electromagnetic Topology. Protective measures are systematically optimized in order to achieve a balance between shielding and filtering. Using the concept of the Generalize...

T. Karlsson

1988-01-01

343

Relativistic causality and conservation of energy in classical electromagnetic theory  

NASA Astrophysics Data System (ADS)

Causality puts certain constraints on the change of the electromagnetic field due to the change in motion of charged particles. Naive calculations of the electromagnetic energy and the work performed by the electromagnetic fields which take these constraints into account might lead to paradoxes involving the apparent nonconservation of energy. A few paradoxes of this type for the simple motion of two charges are presented and resolved in a quantitative way providing deeper insight into various relativistic effects in classical electromagnetic theory.

Kislev, A.; Vaidman, L.

2002-12-01

344

Cascade control strategy design for electromagnetic guidance system  

Microsoft Academic Search

This work simulates lateral motion in magnetic levitation (maglev) transportation systems using a novel electromagnetic guidance device. First, current control modules, a pulse-width-modulation (PWM) controller and buck converter, are used for driving electromagnets. The electromagnetic guidance system, which has two current control modules, a gap controller, and a bipolar switching mechanism, controls the gap between the moving platform and rail.

Jeng-Dao Lee; Zhi-Bin Wang; Jia-Qi Lu; Xuan-Ren Chen; Rou-Yong Duan

2011-01-01

345

Simulating Electromagnetic Interactions in High Power Density Inverters  

Microsoft Academic Search

In high power density inverters with integrated functions like filters and control electronics electromagnetic interaction between components becomes an important issue. Especially filters for electromagnetic interference are very sensitive to electromagnetic fields and therefore critical to design. Nevertheless only few guidelines for optimizing placement of filter components were published up to now. This paper introduces a simulation method for predicting

E. Hoene; A. Lissner; S. Weber; S. Guttowski; W. John; H. Reichl

2005-01-01

346

Relativistic Theory of the Propagation of Plane Electromagnetic Waves  

Microsoft Academic Search

Based on the complete set of equations of thermodynamics of irreversible processes of a fluid in electromagnetic fields, a relativistic theory of the influence of electromagnetic waves on a simple fluid is developed. In particular, the oscillations of the fluid induced by a plane electromagnetic wave are evaluated, and the energy-momentum tensor is determined. It is further conjectured that Minkowski's

C. L. Tang; J. Meixner

1961-01-01

347

Nonlinear propagation of intense electromagnetic waves in weakly ionized plasmas  

Microsoft Academic Search

The nonlinear propagation of intense electromagnetic waves in weakly-ionized plasmas is considered. Stimulated scattering mechanisms involving electromagnetic and acoustic waves in an unmagnetized plasma are investigated. The growth rate and threshold for three-wave decay interactions as well as modulational and filamentation instabilities are presented. Furthermore, the electromagnetic wave modulation theory is generalized for weakly ionized collisional magnetoplasmas. Here, the radiation

P. K. Shukla

1993-01-01

348

The scattering of electromagnetic waves from rough surfaces  

Microsoft Academic Search

The theory and applications of scattering of electromagnetic waves from rough surfaces are addressed. The topics considered include: the general Kirchoff solution for scattering from rough surfaces; periodically rough surfaces; random rough surfaces: surfaces generated by random processes and other models; the statistical distribution of the scattered field; depolarization of electromagnetic waves scattered from a rough surface; reflection of electromagnetic

Petr Beckmann; Andre Spizzichino

1987-01-01

349

Electromagnetic pulse interaction notes--EMP 3-38  

Microsoft Academic Search

This is a series of five notes on electromagnetic pulse interaction. Subjects covered in this volume are: electromagnetic shielding by advanced composite materials; fields in a rectangular cavity excited by a plane wave on an elliptical aperture; transient electromagnetic characterization of arbitrary conducting bodies through an aperture-perforated conducting screen; a comparison of stick model skin current predictions with scale model

C. E. Baum

1979-01-01

350

Study of 3D formulations to model electromagnetic devices  

Microsoft Academic Search

For simulation of electromagnetic devices it is necessary to solve simultaneously the electromagnetic and electric circuit equations. Then the difficulties are in the choice of magnetic formulations to take into account the electric circuit equations with a limited number of unknowns. In this communication, we present and discuss several electromagnetic formulations. The cases of stranded and solid conductors are considered

Stefan Bouissou; Francis Piriou

1994-01-01

351

Locally resonant cavity cell model for electromagnetic band gap structures  

Microsoft Academic Search

Mushroom-like electromagnetic band gap (EBG) structures exhibit unique electromagnetic properties that have found a wide range of electromagnetic device applications. This paper focuses on the local resonance behaviors of EBG structures, and a simply locally resonant cavity cell (LRCC) model for mushroom-like EBG structures is presented to gain insight to the physical mechanism of the EBG structures and the interaction

Long Li; Bin Li; Hai-Xia Liu; Chang-Hong Liang

2006-01-01

352

Molecular Expressions: Science, Optics & You: The Nature of Electromagnetic Radiation  

NSDL National Science Digital Library

This web site is a tutorial for beginning physics students on the topic of electromagnetic radiation. Written for non-physics majors, it introduces the electromagnetic spectrum and contains links to related interactive Java simulations. This item is part of a larger collection of reference materials, simulations, and curriculum support on the topic of electromagnetism.

Davidson, Michael; Abramowitz, Mortimer

2008-06-11

353

EML - an electromagnetic levitator for the International Space Station  

Microsoft Academic Search

Based on a long and successful evolution of electromagnetic levitators for microgravity applications, including facilities for parabolic flights, sounding rocket missions and Spacelab missions, the Electromagnetic Levitator EML provides unique experiment opportunities onboard ISS. With the application of the electromagnetic levitation principle under microgravity conditions the undercooled regime of electrically conductive materials becomes accessible for an extended time which allows

A Seidel; W Soellner; C Stenzel

2011-01-01

354

Nonthermal millimeter electromagnetic field effect on the marine luminous bacteria  

Microsoft Academic Search

The nonthermal intensity millimeter electromagnetic field effect on the marine luminous bacteria are presented. The unique ability of luminous bacteria to emit light provides an opportunity for study of effects induced by electromagnetic fields. Therefore, the peculiarities of effects induced by electromagnetic radiation of the millimeter wavelengths and nonthermal intensity on the marine luminous bacteria Photobacterium leiognathi, strain 54 were

T. V. Drokina; L. U. Popova; M. A. Bitekhtina; G. A. Petrakovskii; D. A. Velikanov

2005-01-01

355

Scattering of Electromagnetic Waves by Periodic Rough Surfaces  

Microsoft Academic Search

Periodic structures often appear in the applications such as antenna design, microwave systems, metamaterials etc. and the analysis of electromagnetic wave propagation in such structures has an important place in the electromagnetic theory. Among them scattering of electromagnetic waves from rough surfaces is important due to both theoretical and practical points of view. For the periodic surfaces having a slow

S Yildiz; Y Altuncu; O Ozdemir

2006-01-01

356

Screening My Calls: Scale and the Electromagnetic Spectrum  

NSDL National Science Digital Library

Light is just one type of electromagnetic radiation; it belongs to the visible portion of the electromagnetic (EM) spectrum. The other regions of the EM spectrum include everything from gamma rays to radio waves. They are all the same thing: electromagnet

Taylor, Amy R.; Jones, M. G.; Falvo, Michael R.

2009-04-01

357

Advances in Electromagnetic Launch Science and Technology and Its Applications  

Microsoft Academic Search

The U.S. continues a broad spectrum of research to provide the scientific underpinnings for electromagnetic launch. These efforts include fundamental research on materials, properties of materials subjected to electromagnetic and thermal stresses, railguns (particularly the rail-armature sliding interface), coilguns, and energy storage and power conditioning. There is also broad and growing interest in novel applications of electromagnetic launch. For example,

H. D. Fair

2009-01-01

358

Fuzzy Logic Implementation Of An Electromagnetic Interactions Modelling Tool  

Microsoft Academic Search

An electromagnetic interactions modelling tool which is based on a fuzzy logic representation of the electromagnetic attributes in a topological decomposition of a system is described. The purpose of this tool is to help determine any electromagnetic compatibility problems in complex systems. This tool is an extension of the HardSyslHardDraw software (l, 21 enabling it to handle a fuzzy representation

J. Lo Vetri; William H. Henneker

1992-01-01

359

Electromagnetic interference analysis of magnetic resistance sensors inside a projectile under complex electromagnetic environments  

NASA Astrophysics Data System (ADS)

Accurate measurement of angular motion has long been recognized as a daunting task. In recent years the measurement of projectiles utilizing magnetic resistance sensors has become a hot research field. Electromagnetic interference on attitude measurement cannot be ignored in complex electromagnetic environments such as battlefield conditions. In this paper, the influence and function pattern of electromagnetic interference on the measuring performance are theoretically analyzed, and the shielding effectiveness (SE) simulation of projectile is conducted via software Computer Simulation Technology (CST). Considering the specific tests, the intensity of the influence is judged. The simulation indicates that the battlefield's complex electromagnetic environment influences the environment inside the projectile, especially its electronic components and capability. The research results can provide important theoretical support on the errors compensation and precision improvement of the projectile attitude measurement with Magnetic Resistance sensor.

Guo, Qingwei; Gao, Min; Lu, Zhicai; Yang, Peijie

2013-03-01

360

Electromagnetic-wave propagation along curved surfaces  

NASA Astrophysics Data System (ADS)

We show that Maxwell’s equations for a nonmagnetic, isotropic, but electrically inhomogeneous medium in the absence of charges or current sources lead to a wave equation governing surface electromagnetic wave propagation along a general curved, smooth surface which, when recasted using an appropriate choice of curvilinear coordinates u1,u2,u3 , can be fully separated in the spatial dimensions. It is shown that surface electromagnetic wave solutions decay exponentially away from the surface (along the u3 coordinate) with the same decay rate independent of the shape of the surface. Transmission and reflection coefficients governing scattering of electromagnetic waves on a varying surface shape are derived. Two test cases of a Gaussian-shaped and a sinusoidal-shaped surface are solved in details and discussed numerically in terms of transmission and reflection coefficients including dependencies on surface-shape parameters in the wavelength range 250-750 nm. The present method for determining surface electromagnetic wave propagation along complex-shaped metal-dielectric surfaces allows better insight into the importance of surface geometry as well as considerably faster computational speeds than those provided by standard numerical methods.

Willatzen, M.

2009-10-01

361

Electromagnetic-wave propagation along curved surfaces  

SciTech Connect

We show that Maxwell's equations for a nonmagnetic, isotropic, but electrically inhomogeneous medium in the absence of charges or current sources lead to a wave equation governing surface electromagnetic wave propagation along a general curved, smooth surface which, when recasted using an appropriate choice of curvilinear coordinates u{sup 1},u{sup 2},u{sup 3}, can be fully separated in the spatial dimensions. It is shown that surface electromagnetic wave solutions decay exponentially away from the surface (along the u{sup 3} coordinate) with the same decay rate independent of the shape of the surface. Transmission and reflection coefficients governing scattering of electromagnetic waves on a varying surface shape are derived. Two test cases of a Gaussian-shaped and a sinusoidal-shaped surface are solved in details and discussed numerically in terms of transmission and reflection coefficients including dependencies on surface-shape parameters in the wavelength range 250-750 nm. The present method for determining surface electromagnetic wave propagation along complex-shaped metal-dielectric surfaces allows better insight into the importance of surface geometry as well as considerably faster computational speeds than those provided by standard numerical methods.

Willatzen, M. [Mads Clausen Institute for Product Innovation, University of Southern Denmark, Alsion 2, DK-6400 Soenderborg (Denmark)

2009-10-15

362

Optimization of an Electromagnetic Energy Harvesting Device  

Microsoft Academic Search

This paper presents the modeling and optimization of an electromagnetic-based generator for generating power from ambient vibrations. Basic equations describing such generators are presented and the conditions for maximum power generation are described. Two-centimeter scale prototype generators, which consist of magnets suspended on a beam vibrating relative to a coil, have been built and tested. The measured power and modeled

Chitta Ranjan Saha; Terence O'Donnell; Heiko Loder; Steve Beeby; John Tudor

2006-01-01

363

TOPOLOGICAL ELECTROMAGNETISM FOR QUARKS AND LEPTONS  

SciTech Connect

As outgrowth of a topological bootstrap theory of strong interactions and precursor to a corresponding theory of weak interactions, we propose a representation of electromagnetic interactions for "elementary" hadrons and leptons through combinatorial topology. The representation supports the prediction of four lepton doublets.

Chew, G.F.; Poenaru, V.

1980-04-01

364

Electromagnetic fields in bone repair and adaptation  

NASA Astrophysics Data System (ADS)

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.

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

1995-01-01

365

Progress in Electromagnetic Launch Science and Technology  

Microsoft Academic Search

Electromagnetic (EM) launch science and technology in the United States continues to advance at a significant pace. The computational and experimental tools for understanding the critical physics issues are sufficiently mature that they are being utilized to provide insight and resolution of the remaining major technical challenges. For example, the primary computational electrodynamics code, EMAP3D, is now implemented in a

Harry D. Fair

2007-01-01

366

Measurements of electromagnetic bias in radar altimetry  

Microsoft Academic Search

The accuracy of satellite altimetric measurements of sea level is limited in part by the influence of ocean waves on the altimeter signal reflected from the sea surface. The difference between the mean reflecting surface and mean sea level is the electromagnetic bias. The bias is poorly known, yet for such altimetric satellite missions as the Topography Experiment (TOPEX)\\/Poseidon it

W. K. Melville; R. H. Stewart; W. C. Keller; J. A. Kong; D. V. Arnold; A. T. Jessup; M. R. Loewen; A. M. Slinn

1991-01-01

367

Inverse electromagnetic scattering models for sea ice  

Microsoft Academic Search

Inverse scattering algorithms for reconstructing the physical properties of sea ice from scattered electromagnetic field data are presented. The development of these algorithms has advanced the theory of remote sensing, particularly in the microwave region, and has the potential to form the basis for a new generation of techniques for recovering sea ice properties, such as ice thickness, a parameter

K. M. Goldenl; D. Borup; M. Cheney; E. Cherkaeva; M. S. Dawson; Kung-Hau Ding; A. K. Fung; D. Isaacson; S. A. Johnson; Arthur K. Jordan; Jin Au Kong; Ronald Kwok; Son V. Nghiem; Robert G. Onstott; J. Sylvester; D. P. Winebrenner; I. H. H. Zabel

1998-01-01

368

A topological theory of the electromagnetic field  

Microsoft Academic Search

It is shown that Maxwell equations in vacuum derive from an underlying topological structure given by a scalar field ? which represents a map S3×R?S2 and determines the electromagnetic field through a certain transformation, which also linearizes the highly nonlinear field equations to the Maxwell equations. As a consequence, Maxwell equations in vacuum have topological solutions, characterized by a Hopf

Antonio F. Rañada

1989-01-01

369

A topological theory of the electromagnetic field  

Microsoft Academic Search

It is shown that Maxwell equations in vacuum derive from an underlying topological structure given by a scalar field varphi which represents a map S 3× R--> S 2 and determines the electromagnetic field through a certain transformation, which also linearizes the highly nonlinear field equations to the Maxwell equations. As a consequence, Maxwell equations in vacuum have topological solutions,

Antonio F. Rañada

1989-01-01

370

Interaction theory of the electromagnetic field  

Microsoft Academic Search

An analysis of the field concept and its description in terms of field variables leads to the development of an Interaction Theory of the electromagnetic field with the following properties: (1) it is free of self-interaction terms; (2) the point charge model remains a viable conceptual element of the theory; (3) radiative reaction is fully accounted for within the framework

Solomon L. Schwebel

1972-01-01

371

Broadband Electromagnetic Pulses Coinciding with Sprite Luminosity  

NASA Astrophysics Data System (ADS)

This study reports novel optical sprite observations in southern France during the summer months 2009 and the associated electromagnetic radiation emitted in the frequency range >50 kHz. About 10% of the observed sprites are associated with consecutive pulses of >50 kHz electromagnetic radiation. Some of these broadband pulses occur simultaneously with the sprite luminosity. In particular, the electromagnetic radiation of the sprite itself can coincide with a broadband pulse. This behaviour is predicted by the relativistic runaway breakdown theory, in which the lightning electromagnetic field accelerates free electrons to form a narrow particle beam shooting upward into near-Earth space. This vertical relativistic runaway breakdown describes a novel physical process within the Earth's atmosphere, even though it may occur only on extremely rare occasions, i.e., ~100 upward particle beams per day around the globe. The wealth of currently planned future space missions in this research area will greatly enhance the detection likelihood of the predicted particle beams.

Fullekrug, M.; Roussel-Dupre, R. A.; Symbalisty, E.; Chanrion, O.; van der Velde, O. A.; Odzimek, A.; Whitley, T.; Neubert, T.

2009-12-01

372

Central Mechanism of Action of Electromagnetic Fields.  

National Technical Information Service (NTIS)

The article reviews the literature to date on the effect of electromagnetic fields (EMF) on the central nervous system. Different aspects of the subject are examined: role of natural EMF in the evolutionary processes and their influence on animals and man...

K. V. Sudakov G. D. Antimonii

1973-01-01

373

Electromagnetic propagation into reinforced-concrete walls  

Microsoft Academic Search

A rigorous method for analyzing building construction materials, using finite-element techniques and an expansion of fields in Floquet's modes, is presenteded in this paper. It allows us to precisely study the electromagnetic properties of buildings walls in terms of transmission and reflection characteristics, which can be useful in the design of wireless communication systems. First, we present the influence of

E. Richalot; M. Bonilla; Man-Fai Wong; V. Fouad-Hanna; H. Baudrand; J. Wiart

2000-01-01

374

Causes of Spurious Solutions in Electromagnetics.  

National Technical Information Service (NTIS)

The problem of spurious solutions in finite-element methods for electromagnetics is discussed with the explicit aim to re-open the discussion on this much debated subject. First an overview is given of existing ideas about the causes of spurious solutions...

G. Mur I. E. Lager

2000-01-01

375

Electromagnetic optimization exploiting aggressive space mapping  

Microsoft Academic Search

We propose a significantly improved space mapping (SM) strategy for electromagnetic (EM) optimization. Instead of waiting for upfront EM analyses at several base points, our new approach aggressively exploits every available EM analysis, producing dramatic results right from the first step. We establish a relationship between the novel SM optimization and the quasi-Newton iteration for solving a system of nonlinear

John W. Bandler; R. M. Biernacki; Shao Hua Chen; Ronald H. Hemmers; Kaj Madsen

1995-01-01

376

Structural mechanics for electromagnetic rail guns  

Microsoft Academic Search

The objective of this investigation is to explore potential designs and appropriate materials for a lightweight fieldable electromagnetic rail gun. Lessons learned from the previous launcher designs are reviewed and discussed from a mechanics point of view. Analyses are performed with a conceptually workable gun bore to illustrate the requirement of a fieldable gun construction. Both static and dynamic responses

Jerome T. Tzeng

2004-01-01

377

Development of an advanced electromagnetic gun barrel  

Microsoft Academic Search

An advanced electromagnetic gun (AEMG) barrel was developed for the US Air Force Wright Laboratory (Armament Directorate) to repetitively accelerate large mass projectiles. The AEMG barrel used 5-m rails, had a 50-mm square bore, and was designed to operate at a peak current of 1.5 MA (bore pressure 25 ksi). Key technical achievements included (1) an efficient barrel containment structure

T. W. Hurn; J. D'Aoust; L. Sevier; R. Johnson; J. Wesley

1993-01-01

378

Accuracy Assessment for AG500, Electromagnetic Articulograph  

ERIC Educational Resources Information Center

|Purpose: The goal of this article was to evaluate the accuracy and reliability of the AG500 (Carstens Medizinelectronik, Lenglern, Germany), an electromagnetic device developed recently to register articulatory movements in three dimensions. This technology seems to have unprecedented capabilities to provide rich information about time-varying…

Yunusova, Yana; Green, Jordan R.; Mefferd, Antje

2009-01-01

379

Nuclear electromagnetic pulse (NEMP) hardened cables  

Microsoft Academic Search

When a system is exposed to a Nuclear Electromagnetic Pulse (NEMP), the cables which are used to connect the components act as antennas and couple NEMP energy into the system. The purpose of the program is to develop shields for a 26-pair communications cable which will significantly reduce the NEMP pickup. Because of the technical approach employed, however, many results

W. C. Wells

1975-01-01

380

Nuclear electromagnetic pulse (NEMP) hardened cables  

Microsoft Academic Search

Energy from a Nuclear Electromagnetic Pulse (NEMP) couples into a system via the interconnecting cables. Calculations of the current induced on the sheath of a horizontal cable above a ground plane are discussed. These currents on the exterior of the sheath then excite the interior of the cable via the surface transfer impedance (Z sub T). The objective of reducing

W. C. Wells; Y. Shiau

1976-01-01

381

Nuclear Electromagnetic Pulse (NEMP) Hardened Cables.  

National Technical Information Service (NTIS)

When a system is exposed to a Nuclear Electromagnetic Pulse (NEMP), the cables which are used to connect the components act as antennas and couple NEMP energy into the system. The purpose of the program is to develop shields for a 26-pair communications c...

W. C. Wells

1975-01-01

382

Electromagnetic Mass--Separation and Its Applications  

SciTech Connect

The article describes the electromagnetic mass-separation method and its application in nuclear and solid state physics. The limited review of the results in these fields, obtained by scientific groups at the Physics Institute, Maria Curie Sklodowska University, Lublin, Poland and the Joint Institute for Nuclear Research, Dubna, Russia is presented.

Maoczka, D. [Institute for Atomic Energy, Swierk-Warsaw (Poland); Joint Institute for Nuclear Research, Dubna (Russian Federation); Turek, M.; Latuszynski, A. [Institute of Physics, Maria Curie-Sklodowska University, Lublin (Poland); Yushkevich, Yu. V. [Joint Institute for Nuclear Research, Dubna (Russian Federation)

2009-03-31

383

Standardized evaluation method for electromagnetic tracking systems  

Microsoft Academic Search

The major aim of this work was to define a protocol for evaluation of electromagnetic tracking systems (EMTS). Using this protocol we compared two commercial EMTS: the Ascension microBIRD (B) and NDI Aurora (A). To enable reproducibility and comparability of the assessments a machined base plate was designed, in which a 50 mm grid of holes is precision drilled for

Johann Hummel; Calvin Maurer Jr.; Michael Figl; Michael Bax; Helmar Bergmann; Wolfgang Birkfellner; Ramin Shahidi

2005-01-01

384

Electromagnetic geodesic acoustic modes in tokamak plasmas  

SciTech Connect

The drift kinetic equation is solved for investigation of the plasma response to electromagnetic geodesic acoustic modes. The plasma flow within magnetic surfaces is considered. A perpendicular magnetic perturbation with poloidal number m=2 is created due to the m=2 parallel return current.

Zhou Deng [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

2007-10-15

385

Electromagnetic field quantization in a nonlinear medium  

SciTech Connect

The electromagnetic field in a nonlinear magnetodielectric medium is quantized by modeling the medium with two quantum fields, namely E and M. The vector potential, electric and magnetic polarization densities of the medium, Maxwell and constitutive equations of the medium are found.

Kheirandish, F. [Department of Physics, Faculty of Science, University of Isfahan, Isfahan Iran (Iran, Islamic Republic of); Isfahan Quantum Optics Group (IQOG), University of Isfahan (Iran, Islamic Republic of); Amooshahi, M.; Amooghorban, E. [Department of Physics, Faculty of Science, University of Isfahan, Isfahan Iran (Iran, Islamic Republic of)

2009-07-07

386

Scattering of electromagnetic waves by drift modes  

NASA Astrophysics Data System (ADS)

It is shown that high-frequency electromagnetic waves can parametrically excite the convection and ion drift waves in a slightly inhomogeneous magnetized plasma. The growth rates of the nonlinear decay instabilities are obtained analytically. Permanent address: Electrical Engineering Department, Faculty of Engineering, Cairo University, Giza, Egypt.

Shukla, P. K.; Yu, M. Y.; El-Nadi, Adel

1984-12-01

387

Propagation of Electromagnetic Fields Over Flat Earth.  

National Technical Information Service (NTIS)

This report looks at the interaction of radiated electromagnetic fields with earth ground in military or law- enforcement applications of high- power microwave (HpM) systems. For such systems to be effective, the microwave power density on target must be ...

J. R. Miletta

2001-01-01

388

Impact of Fog on Electromagnetic Wave Propagation  

Microsoft Academic Search

This experiment was designed to explore the impact of fog on electromagnetic radiation, in particular microwaves and infrared light. For years law enforcement agencies have used microwave radiation (radar guns) to measure the speed of vehicles, and the last ten years has seen increased use of LIDAR, which uses 905-nm infrared radiation rather than microwaves. To evaulate the effect of

Jonathon Morris; Daniel Fleisch

2002-01-01

389

Electromagnetic energy and momentum in moving media  

Microsoft Academic Search

The problem of the electromagnetic energy-momentum tensor is among the oldest and the most controversial in macroscopic electrodynamics. In the center of the issue is a dispute about the Minkowski and the Abraham tensors for moving media. An overview of the current situation is presented. After putting the discussion into a general Lagrange-Noether framework, the Minkowski tensor is recovered as

Y. N. Obukhov

2008-01-01

390

Active electromagnetic structures, metamaterials, and antennas  

Microsoft Academic Search

If we are limited to rearranging passive materials such as dielectrics and metals, then the performance of antennas, artificial materials, and other electromagnetic structures that we build will always be determined by the same fundamental limitations that affect today's designs. By including active circuits, it is possible to exceed the limitations of passive structures and to build materials and devices

Daniel Sievenpiper; Minu Jacob; Jiang Long

2012-01-01

391

Electromagnetic mass differences of pions and kaons  

Microsoft Academic Search

We use the Cottingham method to calculate the pion and kaon electromagnetic mass differences with as few model-dependent inputs as possible. The constraints of chiral symmetry at low energy, QCD at high energy, and experimental data in between are used in the dispersion relation. We find excellent agreement with experiment for the pion mass difference. The kaon mass difference exhibits

John F. Donoghue; Antonio F. Perez

1997-01-01

392

Shielding efficiency measurements under pulsed electromagnetic fields  

Microsoft Academic Search

The paper describes a method of using the transfer function of a given system to calculate the shielding efficiency (SE) of a protective screen with the help of measurements conducted in the time domain. A high voltage electromagnetic pulse simulator (EMPS) creates the required pulse fields. The radiated field in the working zone of the simulator is measured by a

V. Venkateswarlu; Y. Narayana Rao

1995-01-01

393

Microchip laser sensor of electromagnetic field  

Microsoft Academic Search

We have developed the photonic sensor of electromagnetic field. The electrooptical phase modulator inserted in one laser cavity performs frequency modulation of the laser due to voltage induced in the antenna probe. The heterodyne detection allows to move the spectrum of modulated optical frequencies into the RF or microwave ranges. The issue of our solution is inserting of both lasers

Arkadiusz J. Antonczak; Krzysztof M. Abramski

2005-01-01

394

Electromagnetic Fields Estimation Using Spatial Statistics  

Microsoft Academic Search

The spatial statistics formalism is applied to electromagnetic fields analysis. Fields are considered as realizations of a random function. Their spatial structure is studied by a method known as variographic analysis. To infer unknown values of the fields, an interpolation method called kriging is then used. It is shown how kriging can be performed on experimental or numerical data to

Ph. De Doncker; J.-M. Dricot; R. Meys; M. Hélier; W. Tabbara

2006-01-01

395

Electromagnetic Interference and Shielding: An Introduction. (Revised).  

National Technical Information Service (NTIS)

The basic equations of the electromagnetc field are summarized as far as they are needed in the theory of ElectroMagnetic Interference and Shielding. Through the analysis of the radiation from small current-carrying wires ('electric dipole') and small cur...

A. T. de Hoop D. Quak

1993-01-01

396

Electromagnetic interference and solid state protective relays  

Microsoft Academic Search

This paper presents new information on the nature of the electromagnetic environment in an electric power station which can influence the performance of modern solid state protective relays and other sensitive electronic control and data processing equipments. Present industry standard tests do not simulate the full range of this environment and may need to be revised. The frequency spectrum of

W. C. Kotheimer; L. L. Mankoff

1977-01-01

397

Electromagnetic interference shielding effectiveness of carbon materials  

Microsoft Academic Search

Carbon materials for electromagnetic interference (EMI) shielding are reviewed. They include composite materials, colloidal graphite and flexible graphite. Carbon filaments of submicron diameter are effective for use in composite materials, especially after electroplating with nickel. Flexible graphite is attractive for EMI gaskets.

D. D. L. Chung

2001-01-01

398

MATHEMA: A Constructivist Enviroment for Electromagnetism Learning  

Microsoft Academic Search

In this paper we describe the Web-based adaptive educational hypermedia system called MATHEMA. In general, the MATHEMA is a learning system that dynamically generates courses in electromagnetism according to studentspsila learning goal, knowledge level, performance, learning style, abstract or concrete dimension of learning style, preference for visual and\\/or verbal feedback, preference for the kind of navigation, and preference of using

Alexandros Papadimitriou; Georgios Gyftodimos; Maria Grigoriadou

2009-01-01

399

Electromagnetic Relations in a Single Coordinate System  

Microsoft Academic Search

Certain experimental phenomena, like the homopolar generator, whose analyses have caused confusion are shown to be understandably treated by the following: Use the differential form of Maxwell's four field relations together with the Lorentz force equation as the fundamental relations for treating all electromagnetic phenomena in the observer's coordinate system. The Lorentz force is considered to act on all of

Emerson M. Pugh

1964-01-01

400

Electromagnetic pulse effect on civilian facilities  

Microsoft Academic Search

The Office of Energy Storage and Distribution of the US Department of Energy has formulated a research and development program for the assessment and protection of electric power systems when subjected to nuclear electromagnetic pulses (EMPs). This program addresses a problem which is an international concern, and unclassified information is being shared among the United States, West Germany, the United

Serafin

1986-01-01

401

Photino bremsstrahlung in intense electromagnetic fields  

Microsoft Academic Search

We calculate the probability for the emission of a pair of photinos by an electron moving in a background electromagnetic field. The rate of the process e ? e?? is estimated at different values of the field strength and electron energies. Comparing the cooling rate of some astrophysical objects via photino bremsstrahlung with another competing energy-loss mechanism we find new

Alexander V. Kurilin; Aleksey I. Ternov

1996-01-01

402

Multifunctional composites: Healing, heating and electromagnetic integration  

Microsoft Academic Search

Multifunctional materials, in the context of this research, integrate other functions into materials that foremost have outstanding structural integrity. Details of the integration of electromagnetic, heating, and healing functionalities into fiber-reinforced polymer composites are presented. As a result of fiber\\/wire integration through textile braiding and weaving, the dielectric constant of a composite may be tuned from negative to positive values.

Thomas Anthony John Plaisted

2007-01-01

403

Reconnection electromagnetic launcher (RCEML) and its application  

Microsoft Academic Search

RCEML is a special electromagnetic device. In this paper, the equation of motion of the RCEML is presented. Speed characteristic of RCEML and autostability of projectile have been studied. A 1000-stage RCEML device is designed and simulated for a small satellite on the basis of the research for the single-stage RCEML. The parametric evaluations of the RCEML have been concluded

Cheng Shukang; Li Xiaopeng; Li Liyi; Gao Hanying; Hu Yusheng

2003-01-01

404

Electromagnetic propulsion: drag and erosion modeling  

Microsoft Academic Search

Railgun electromagnetic accelerators are currently being designed for hypervelocity projectile launch in equation of state impact experiments. Launcher development is proceeding in successive stages of increased acceleration and velocity with a goal of launching sabot-supported 1 g projectiles at speeds near 100 km\\/s. The railgun utilizes Lorentz force produced by the current in an electrically conducting moving armature interacting with

Buckingham

1980-01-01

405

Electromagnetic ''particle-in-cell'' plasma simulation  

SciTech Connect

''PIC'' simulation tracks particles through electromagnetic fields calculated self-consistently from the charge and current densities of the particles themselves, external sources, and boundaries. Already used extensively in plasma physics, such simulations have become useful in the design of accelerators and their r.f. sources. 5 refs.

Langdon, A.B.

1985-04-22

406

Electromagnetic particle-in-cell plasma simulation  

Microsoft Academic Search

PIC simulation tracks particles through electromagnetic fields calculated self consistently from the charge and current densities of the particles themselves, external sources, and boundaries. Already used extensively in plasma physics, such simulations have become useful in the design of accelerators and their r.f. sources.

A. B. Langdon

1985-01-01

407

Interference between two electromagnetically induced transparencies  

Microsoft Academic Search

Summary form only given. We study interference between electromagnetically induced transparency (EIT) features in the radio frequency region of the spectrum associated with an electron spin resonance in the nitrogen-vacancy center in diamond. Measurements are made using a coherent optical detection technique. Two EIT features can be induced in a single absorption band by two coupling fields at different frequencies.

N. B. Manson; C. Wei; J. P. D. Martin; E. Wilson

2000-01-01

408

A new Model of Electromagnetic Magnetospheric Fields  

Microsoft Academic Search

Presentation of the electromagnetic fields in terms of the Euler potentials is ideal in modelling of the magnetic and electric fields in large-scale magnetospheric plasmas: The electric field consistent with the frozen-in condition including also the contribution arising from the temporal variations of the magnetic field can be easily obtained. Here, a recent model based on explicit Euler potentials is

P. K. Toivanen

2008-01-01

409

Modeling of electromagnetic fields reflected by runes  

Microsoft Academic Search

The technique of computer design of the parameters of the electromagnetic field reflected by the FEHU rune is shown. The geometrical optics techniques are used for the exact analysis of the phase vibrations reflected by the rune. We demonstrate influencing of the Fehu rune on same bio-object parameters, which were used as the detector of action.

O. P. Maksimyak; L. Y. Podkamen

2007-01-01

410

Parallel Computer Modeling of Complex Electromagnetic Systems  

Microsoft Academic Search

The HFSS frequency domain computer code, installed on an AIX-3 computer, was used to model a geometrically complex electromagnetic system operating over many decades of frequencies in nonhomogeneous media. First, we used a single processor unit, and then 16 processors operating in parallel. Since the Maxwell equations used in the HFSS code show no time dependence, parallel processing can be

A. S. Podgorski; Marek B. Zaremba; M. Vogel

2000-01-01

411

Stochastic Surface Models for Electromagnetic Scattering  

Microsoft Academic Search

\\u000a In this paper use of available geometrical models for stochastic surfaces within the electromagnetic scattering theory is\\u000a presented. Classical and fractals models are introduced. The following discussion focuses on the geometrical models complexity,\\u000a accuracy and applicability to analytically achieve closed form solutions of the scattered field.

Giorgio Franceschetti; Daniele Riccio I

412

Measurement and modeling of soil electromagnetic behavior  

Microsoft Academic Search

The paper presents procedures to measure and model soil electromagnetic parameters, as a function of frequency, adequate for frequency domain and transient studies of soil behavior and its effect in grounding. Such procedures take into account the problems related to field measurements, the need of a physical validation, and the great diversity of soil characteristics. The physical model, with a

Carlos Portela

1999-01-01

413

Finite element modeling of electromagnetic NDT phenomena  

Microsoft Academic Search

The development of computer-based defect characterization schemes for automated electromagnetic methods of nondestructive testing (NDT) requires adequate mathematical models to describe the complicated interactions of currents, fields and defects in materials. This paper describes the finite element equations governing active, residual and eddy current phenomena in materials with discontinuities and magnetic nonlinearity. It is suggested that the resulting magnetic vector

R. Palanisamy; W. Lord

1979-01-01

414

Energy Mental Models: Mechanics through Electromagnetism  

NSDL National Science Digital Library

We investigated students' mental models for energy, and changes in these models in going from mechanics to electromagnetism contexts. We interviewed students in a two-semester calculus-based physics course. Our research design included semi-structured interviews with demonstration. Based on our findings in the interviews we are developing a first version of an 'Energy Mental Model Inventory.'

Itza-Ortiz, Salomon F.; Lawrence, Benjamin; Zollman, Dean A.

2005-11-02

415

Multifield modeling of electromagnetic metal forming processes  

Microsoft Academic Search

The purpose of this work is the formulation of a thermo-magneto-mechanical multifield model and presentation of the numerical strategies applied. In particular, this model is used to simulate electromagnetic sheet metal forming processes (EMF). In this process, deformation of the workpiece is driven by the interaction of a current generated in the workpiece by a magnetic field generated by a

J. Unger; M. Stiemer; B. Svendsen; H. Blum

2006-01-01

416

Microstrip conductor loss models for electromagnetic analysis  

Microsoft Academic Search

This paper describes and rigorously validates single- and multiple-layer models of microstrip conductor loss appropriate for high-accuracy application in electromagnetic analysis software. The models are validated by comparison with measurement and by comparison with converged results. It is shown that in some cases an extremely small cell size is needed in order to achieve convergence. Several effects that make a

James C. Rautio; Veysel Demir

2003-01-01

417

Parametric modeling of transient electromagnetic systems  

Microsoft Academic Search

The modeling of a transient electromagnetic system as a single-input, single-output, linear, causal process is considered. Two canonical forms are discussed; one for impulse function input and the other for more general input. Expressions are derived for errors in the estimation of the model parameters caused by errors in the process data. It is shown that Prony's method is a

D. G. Dudley

1979-01-01

418

Bobbing and Kicks in Electromagnetism and Gravity  

Microsoft Academic Search

We exploit the analogy between gravitation and electromagnetism to gain some insight into the origin and nature of ``bobbing motion'' and momentum ``kicks'' that occur in the merger of black hole binaries with spin. Specifically, we consider two charged magnetic dipoles in a slow-motion approximation, and examine the role that field momentum plays in their motion. As expected, there is

Samuel E. Gralla; Abraham I. Harte; Robert M. Wald

2010-01-01

419

Electromagnetic Transients Program (EMTP) Primer. Final Report.  

National Technical Information Service (NTIS)

This document is an outgrowth of a survey and analysis of Electromagnetic Transients Program (EMTP) user needs, in which improved user's documentation was determined to by the single most important enhancement to the EMTP. The Primer is an EMTP training m...

S. F. Mauser T. E. McDermott

1985-01-01

420

AN ELECTROMAGNETIC INVERSE PROBLEM IN CHIRAL MEDIA  

Microsoft Academic Search

We consider the inverse boundary value problem for Maxwell's equations that takes into account the chirality of a body in R3. More precisely, we show that knowledge of a boundary map for the electro- magnetic fields determines the electromagnetic parameters, namely the conductivity, electric permittivity, magnetic permeability and chirality, in the interior. We rewrite Maxwell's equations as a first order

STEPHEN R. MCDOWALL

421

Electromagnetic inverse problem for dispersive media  

Microsoft Academic Search

The dispersion of transient electromagnetic waves in a homogeneous medium can be characterized by expressing either the complex permittivity as a function of frequency or the susceptibility kernel as a function of time. In this paper, a time domain technique is used to derive a nonlinear integrodifferential equation which relates the susceptibility kernel for a one-dimensional homogeneous slab to the

R. S. Beezley; R. J. Krueger

1985-01-01

422

Transformation media that rotate electromagnetic fields  

Microsoft Academic Search

The authors suggest a way to manipulate electromagnetic waves by introducing a rotation mapping of coordinates that can be realized by a specific transformation of the permittivity and permeability of a shell surrounding an enclosed domain. Inside the enclosed domain, the information from the outside will appear as if it is coming from a different angle. Numerical simulations were performed

Huanyang Chen; C. T. Chan

2007-01-01

423

Low Frequency Electromagnetic Cross-Borehole Imaging.  

National Technical Information Service (NTIS)

Most of the research in cross-borehole electromagnetic (EM) imaging has been done at high frequencies (17 to 200 Mhz). At these frequencies, the propagation distance through-the-earth is limited to less than 8 meters and the attenuation of the signal depe...

M. Pihlman P. E. Harben

1988-01-01

424

Complementary Electromagnetic Non-Destructive Evaluation  

NASA Astrophysics Data System (ADS)

The use of non-destructive evaluation (NDE) for defect detection and failure prediction in structures and specimens is widespread in energy industries, aimed at ageing power plants and pipelines, material degradation, fatigue and radiation damage, etc. At present there are no suitable electromagnetic NDE methods for the measurement and characterization of material degradation, in irradiated samples in particular, which is very important and timely for the nuclear power industry in the UK. This paper reports recent developments in the field of electromagnetic (EM) NDE at Newcastle University, including pulsed eddy current (PEC), pulsed magnetic flux leakage (PMFL), magnetic Barkhausen emission (MBE) and magneto-acoustic emission (MAE). As different EM methods have different strengths, an integrative EM framework is introduced. Case studies through the second round robin tests organized by the Universal Network for Magnetic Non-Destructive Evaluation (UNMNDE), representing eighteen leading research groups worldwide in the area of electromagnetic NDE, are reported. Twelve samples with different ageing times and rolling reduction ratios were tested using different magnetic methods among the UNMNDE members. Based on the studies, the complementary characteristics of electromagnetic techniques for NDE are discussed.

Tian, Gui Yun; Wilson, John; Morozov, Maxim

2011-06-01

425

Electromagnetic Noise in McElroy Mine.  

National Technical Information Service (NTIS)

Two different techniques were used to make measurements of the absolute value of electromagnetic noise in and above an operating coal mine, McElroy Mine, located near Moundsville, West Virginia. 300-volt-dc and 480-volt-ac machinery was measured to see th...

M. Kanda J. W. Adams W. D. Bensema

1974-01-01

426

CONTINUUM ELECTROMAGNETIC RADIATION FROM SOLAR FLARES  

Microsoft Academic Search

Continuum electromagnetic radiation from solar flares is discussed in ; terms of the energy loss processes of electrons in the solar atmosphere. It is ; shown that it is possible to attribute the continuum radiation both at radio ; frequencies and at visible frequencies to synchrotron radiation by exponential ; rigidity distributions of electrons. (auth);

W. A. Stein; E. P. Ney

1963-01-01

427

Electromagnetic Spectrum: Distribution of Radiant Energies  

NSDL National Science Digital Library

This item is a beginning tutorial on the electromagnetic spectrum designed for students of introductory physics. It provides multiple plots of the spectrum to aid users in understanding various EM spectrum classifications. This item is part of a larger tutorial on the topic of Remote Sensing, sponsored by the NASA Goddard Program office.

Short, Nicholas M.

2008-06-12

428

Project Physics Text 4, Light and Electromagnetism.  

ERIC Educational Resources Information Center

Optical and electromagnetic fundamentals are presented in this fourth unit of the Project Physics text for use by senior high students. Development of the wave theory in the first half of the 19th Century is described to deal with optical problems at the early stage. Following explanations of electric charges and forces, field concepts are…

Harvard Univ., Cambridge, MA. Harvard Project Physics.

429

The wave structure of monochromatic electromagnetic radiation  

Microsoft Academic Search

The paper considers a general field of electromagnetic waves of a single frequency and identifies the salient structurally stable features of the three-dimensional pattern of polarization. The approach is geometrical rather than analytical, and it differs from previous treatments of this kind by being applicable even when the constituent plane waves are travelling in all directions. Lines and surfaces exist

J. F. Nye; J. V. Hajnal

1987-01-01

430

Charging Ahead: An Introduction to Electromagnetism.  

ERIC Educational Resources Information Center

This guide explores the connection between electricity and magnetism with middle level and high school students. The phenomenon of electromagnetism is broken down into four lesson plans that provide students and teachers with a carefully constructed yet easy way to learn about their history. All four activities prompt students to use inexpensive,…

Shafer, Larry E.

431

NONLINEAR ANALYSIS OF ELECTROMAGNETIC LINEAR MOTOR COMPRESSORS  

Microsoft Academic Search

For energy conservation in refrigeration and air-conditioning systems, based on vapor compression cycles, capacity modulation is necessary. In addition, individual components of the system have to be improved. Although electromagnetic linear motor compressors are supposed to be most suitable for this purpose, they have not found wide acceptance because the interaction of various design parameters is not completely understood. In

KAZUMITSU NISHIOKA

1980-01-01

432

Maxwell's electromagnetic theory and special relativity.  

PubMed

This paper presents a brief history of electromagnetic theory from ancient times up to the work of Maxwell and the advent of Einstein's special theory of relativity. It is divided into five convenient periods and the intention is to describe these developments for the benefit of a lay scientific audience and with the minimum of technical detail. PMID:18218598

Hall, Graham

2008-05-28

433

Unique Signal Override Plug electromagnetic test report  

SciTech Connect

The MC4039 Unique Signal Override Plug (USOP) provides the unique signal for the B90 when fielded on aircraft that are not equipped with unique signal capability. Since the USOP is field installed, the concern is that it might be susceptible to electromagnetic radiation prior to installation on the weapon. This report documents a characterization of the USOP, evaluates various techniques for attaching electromagnetic shields, and evaluates the susceptibility of a fully assembled passive-USOP. Tests conducted evaluated the electromagnetic susceptibility of the passive, unconnected USOP. During normal operation the USOP is powered directly from the weapon. During the course of this test program two prototypes were developed. The prototype 1 USOP internal circuitry contains one SA3727 chip, five diodes, three resistors, and two capacitors; these are mounted on a circular circuit board and contained inside a metal back shell cover, which serves as an electromagnetic shield. The prototype 2 design incorporated four changes. The manufacturer of the SA3727 chip was changed from Lasarray to LSI Logic, the circuit board ground was tied to the case ground through a straight wire, Cl was changed from 1 microfarad to 0.1 microfarads. and the circuit board was changed, as required. 2 refs., 17 figs., 3 tabs. (JF)

Bonn, R.H.

1990-10-01

434

Electromagnetic field interactions with biological systems  

SciTech Connect

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.

Frey, A.H. (Randomline Inc., Huntingdon Valley, PA (United States))

1993-02-01

435

(p,q)-form Kähler electromagnetism  

NASA Astrophysics Data System (ADS)

We present a gauge invariant generalization of Maxwell's equations and p-form electromagnetism to Kähler manifolds. The result is a detour operator connecting Dolbeault and dual Dolbeault cohomologies and derives from BRST detour quantization of the N=4 supersymmetry algebra. The form of the new equations mimics the linearized Einstein's equations and extends to more general geometric structures.

Cherney, D.; Latini, E.; Waldron, A.

2009-04-01

436

Feedback Control for Electromagnetic Vibration Feeder  

Microsoft Academic Search

An electromagnetic-type vibratory feeder of is a typical transportation device used in automatic weighers. As existing feeders are driven by feedforward control, the so-called ``firing angle control'', the driver cannot negate sudden disturbances. In this study, we consider applying a feedback control for such a feeder system. First, we give the two details of modelings for the vibration part and

Tomoharu Doi; Koji Yoshida; Yutaka Tamai; Katsuaki Kono; Kazufumi Naito; Toshiro Ono

2001-01-01

437

Multiple cell configuration electromagnetic vibration energy harvester  

Microsoft Academic Search

This paper reports the design of an electromagnetic vibration energy harvester that doubles the magnitude of output power generated by the prior four-bar magnet configuration. This enhancement was achieved with minor increase in volume by 23% and mass by 30%. The new 'double cell' design utilizes an additional pair of magnets to create a secondary air gap, or cell, for

Anthony Marin; Scott Bressers; Shashank Priya

2011-01-01

438

Optimisation of electromagnetic vibrational energy harvesting device  

Microsoft Academic Search

This paper describes a model for an electromagnetic based, vibrational power generator and investigates the optimum conditions for load resistance, displacement and voltage in order to extract maximum electrical power from mechanical vibrations. Two macro-generators have been built and tested in order to verify the model.

C. R. Saha; T. O'Donnell; H. Loder

2006-01-01

439

Narrowband Electromagnetic Emissions from Saturn's Magnetosphere.  

National Technical Information Service (NTIS)

During the Voyager 1 flyby of Saturn a series of narrowband electromagnetic emissions were detected by the plasma wave instrument coming from the inner region of the magnetosphere in the frequency range from 3 to 30 kHz. These emissions have many close si...

D. A. Gurnett W. S. Kurth F. L. Scarf

1981-01-01

440

Electromagnetic fields generated by ocean waves  

Microsoft Academic Search

The electromagnetic field generated by a progressive ocean wave in a horizontally stratified ocean is a sum of a transverse electric type field, a transverse magnetic type field, and an electrostatic type field. Seawater velocity components in a vertical plane containing the direction of wave propagation generate the transverse electric part of the field, and the velocity component normal to

Walter Podney

1975-01-01

441

Pulsed operation of a superconductive electromagnetic gradiometer  

Microsoft Academic Search

An electromagnetic gradiometer (EMG) combines a superconducting quantum interference device (SQUID) gradiometer with an active magnetic source for use as an ultrasensitive metal detector. A report on performance tests of an EMG configuration using a pulsed source is presented. Eddy currents persist in metallic targets between pulses and thus make them visible to the receiver. Because the receiver only looks

P. V. Czipott; W. N. Podney

1991-01-01

442

Space environment, electromagnetic fields, and circadian rhythm  

Microsoft Academic Search

Human space activity began in 1961. About 400 persons have gone to space since then, and about 70 of them have stayed more than 1 month. Circadian rhythm and sleep in space have been investigated several times, though the effect of longer stays in space has not been adequately clarified. Electromagnetic fields are different in the space environment, especially in

R. Izumi; N. Ishioka; K. Mizuno; T. Goka

2000-01-01

443

Charging Ahead: An Introduction to Electromagnetism.  

ERIC Educational Resources Information Center

|This guide explores the connection between electricity and magnetism with middle level and high school students. The phenomenon of electromagnetism is broken down into four lesson plans that provide students and teachers with a carefully constructed yet easy way to learn about their history. All four activities prompt students to use inexpensive,…

Shafer, Larry E.

444

Electromagnetic Force on a Moving Dipole  

ERIC Educational Resources Information Center

|We analyse the force acting on a moving dipole due to an external electromagnetic field and show that the expression derived in Vekstein (1997 "Eur. J. Phys." 18 113) is erroneous and suggest the correct equation for the description of this force. We also discuss the physical meaning of the relativistic transformation of current for a closed…

Kholmetskii, Alexander L.; Missevitch, Oleg V.; Yarman, T.

2011-01-01

445

Microstructural diagnosis using electromagnetic wave scattering methodologies  

Microsoft Academic Search

Scattered electromagnetic waves were used in the present work to characterize the microstructural effects on the performance of metallic materials. A Nisb3Al alloy with a dendritic microstructure has exhibited better creep resistance compared to similar alloys having equiaxed microstructure of grains. X-ray diffraction was applied along the dendritic arms to investigate their orientations. Both the interlocking boundaries and crystallographic texture

Kevin Jenn Chien Chou

1998-01-01

446

Electromagnetic scattering calculations for terahertz sensing  

Microsoft Academic Search

This paper presents predictions of classical electromagnetic scattering from granular material illuminated by a terahertz (THz) source. Random media models are created to represent the explosive grains, air voids and filler material commonly found in explosive devices. These constituents can cause significant volume scattering that may alter or obscure the chemical response of the explosive, thus impacting THz detection of

L. M. Zurk; B. Orlowski; G. Sundberg; D. P. Winebrenner; E. I. Thorsos; A. Chen

2007-01-01

447

Low Frequency Electromagnetic Radiation and Genetic Aberrations.  

National Technical Information Service (NTIS)

Adult male Drosophila X(c2) yB/sc(8)y(+) were exposed for 5 days to 75, 60, or 45 Hz, 10v/m and 1 gauss and then mated to y sc(S1) In 49 sc(8); bw; st p(p). The low frequency electromagnetic radiation did not induce any of the following genetic aberration...

S. Mittler

1972-01-01

448

Electromagnetic imaging of dynamic brain activity.  

National Technical Information Service (NTIS)

Neural activity in the brain produces weak dynamic electromagnetic fields that can be measured by an array of sensors. Using a spatio-temporal modeling framework, we have developed a new approach to localization of multiple neural sources. This approach i...

J. Mosher R. Leahy P. Lewis J. Lewine J. George

1991-01-01

449

ALTERNATIVE LABELING SCHEMES IN ELECTROMAGNETIC TOPOLOGY  

Microsoft Academic Search

This paper defines the problems associated with applying graph theory to interaction sequence diagrams used in electromagnetic topology. Because few applications have been developed, the optimal labeling scheme has yet to emerge. As a result, operations on the graph are difficult to record concisely. This paper contains criteria to guide the design of labeling schemes. Some specific schemes are presented

Roger S. Noss

1986-01-01

450

Electromagnetic shielding effectiveness of composite material  

Microsoft Academic Search

The purpose of this paper is to present an engineering study of the electromagnetic shielding effectiveness of composite materials used in space applications. The objective of the study is to identify and quantify the important electrical characteristics of composite materials proposed as substitutes for conventional metal-based structural elements of spacecraft. Current design practices utilized by various developers of spacecraft, particularly

Patrick J. Serna; Gary H. Liechty

1999-01-01

451

Sensitivity analysis for electromagnetic topology optimization problems  

Microsoft Academic Search

This paper presents a level set based method to design the metal shape in electromagnetic field such that the incident current flow on the metal surface can be minimized or maximized. We represent the interface of the free space and conducting material (solid phase) by the zero-order contour of a higher dimensional level set function. Only the electrical component of

Shiwei Zhou; Wei Li; Qing Li

2010-01-01

452

Electromagnetic aircraft launch system development considerations  

Microsoft Academic Search

The US Navy is developing an electromagnetic aircraft launch system for its next generation of aircraft carriers. Its approach to the program is predicated on the state of the technology and expertise of the participants. A revised business model is discussed

R. R. Bushway

2001-01-01

453

The IAT electromagnetic launch research facility  

Microsoft Academic Search

A new electromagnetic launcher research facility is being constructed at the Institute for Advanced Technology (IAT). IAT is federated with the Army Research Laboratory and The University of Texas at Austin. The mission and support for the IAT comes from the U.S. Army. A major task assigned to the IAT is to support the Army's tactical programs in electric armaments

J. V. Parker; D. T. Berry; P. T. Snowden

1997-01-01

454

Infleunces of Electromagnetic Theory on Modern Art  

Microsoft Academic Search

This article deals in particular with the influences of electromagnetic theory (and its findings) on modern art, especially in the second half of the 18th century. The Young-Helmholtz-Maxwell theory of vision not only changed the understanding of the terms \\

A. E. Yilmaz

2009-01-01

455

Grain Refinement Via Electromagnetic Stirring During Solidification.  

National Technical Information Service (NTIS)

The grain-refinement effect of electromagnetic stirring of Sn-Pb alloys during solidification is investigated at higher field strength and in largersized samples. It is found that the grain-refining effect is due to a crystal multiplication phenomenon rat...

W. C. Johnston G. R. Kotler S. O'Hara H. V. Ashcom W. A. Tiller

1965-01-01

456

Electromagnetic formation flight for sparse aperture telescopes  

Microsoft Academic Search

The use of propellant to maintain the relative orientation of multiple spacecraft in a sparse aperture telescope such as NASA's Terrestrial Planet Finder (TPF) poses several issues. These include fuel depletion, optical contamination, plume impingement, thermal emission, and vibration excitation. An alternative is to eliminate the need for propellant, except for orbit transfer, and replace it with electromagnetic control. Relative

D. W. Miller; R. J. Sedwick; E. M. C. Kong; S. Schweighart

2002-01-01

457

The Electromagnetic Armature Force in Railguns  

NASA Astrophysics Data System (ADS)

Plasma armature transaugmented and muzzle-fed railgun experiments were performed in the UTSI 2.4 m, 1 cm bore diameter railgun. These experiments were evaluated with a performance model that included the simple electromagnetic force equation for the particular railgun, viscous and ablation armature drag, and the compression of bore gas ahead of the projectile. This evaluation revealed that at least one of the force or drag models was incorrect. The simple electromagnetic force equations for a "real railgun", one with a finite rail thickness, was derived using the conservation of power at the breech. Strain energy due to the transverse component of current density in the rails, and losses from eddy current generation from field diffusion and armature motion were neglected in this derivation. Three-dimensional (3-D) electromagnetic simulations were performed on a generic square bore railgun configuration with the codes MEGA and MAP3 to determine the seriousness of the losses not included in the derivation. These simulations showed that only a fraction of the force predicted by the simple electromagnetic force model was exerted on the armature. For example, a force of 510 N was predicted for the muzzle -fed railgun at steady-state while a calculated armature force of -170 N was found from the 3-D simulation with a stationary armature. This showed that the simple electromagnetic force model could not be used to predict railgun performance for the muzzle-fed railgun. A modification to the simple electromagnetic force equation is proposed,rm F {=}{+/-} {1over2 } alpha L^' I_sp {1}{2} + beta M^ ' I_1 I_2,where the positive sign gives the force for the transaugmented railgun and the negative sign gives the force for the muzzle -fed railgun. The parameters alpha and beta represent the fraction of force exerted on the armature from the inner and outer rails respectively. 3-D simulations are required to find values for alpha and beta . Evaluation of the transaugmented and muzzle-fed railgun experiments using the modified electromagnetic force equation in the performance model showed that one of the fluid mechanical drag models was still in error.

Taylor, Jaime R.

1995-01-01

458

How Electromagnetic Exposure can influence Learning Processes – Modelling Effects of Electromagnetic Exposure on Learning Processes  

Microsoft Academic Search

Abstract In the last years the public and often political discussion about eventually health hazard effects of high-frequency electromagnetic fields (above all of mobile-phones) on human,beings is increas- ing. The further need of scientific studies to clear up possible ,effects becomes ,more and more obvious. Actually, no one knows for sure how everyday electromagnetic exposure affects the learning and memory

Jochen Kuhn; Campus Landau; Hermann Stever

459

A feasibility study for electromagnetic pollution monitoring by electromagnetic-source localization via neural independent component analysis  

Microsoft Academic Search

The aim of this paper is to present an electromagnetic source localization technique based on independent component analysis (ICA), as a part of a feasibility study for electromagnetic pollution monitoring via neural network techniques. Four ICA algorithms known from the literature, allowing to process complex-valued signals, are used to estimate the propagation parameters of electromagnetic fields emitted by radio-base transmission

Luciano Albini; Pietro Burrascano; Simone Fiori

2003-01-01

460

Of electromagnetic waves and the experimental study on bioeffects of transient electromagnetic fields on cells and its applications  

Microsoft Academic Search

Many hot problems of non-thermal effects of electromagnetic waves, such as the effects on human beings of low frequency electric fields and the mechanism of the interaction between the biology body and low-intensity electromagnetic fields, were discussed. Moreover, experimental studies of transient electromagnetic fields leading to cell membrane deformation were studied and its possible applications presented

Baoyi Wang; Changjun Liu; Hong Zhang; Renling Fan

2000-01-01

461

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Report: Electromagnetic Interface (EMI)/Electromagnetic Radiation (EMR) and Electromagnetic Compatibility (EMC), for the METSAT/METOP AMSU-A1.  

National Technical Information Service (NTIS)

This document contains the procedure and the test results of the Advanced Microwave Sounding Unit-A (AMSU-A) Electromagnetic Interference (EMI), Electromagnetic Susceptibility, and Electromagnetic Compatibility (EMC) qualification test for the Meteorologi...

A. Valdez

1999-01-01

462

A strong permanent magnet-assisted electromagnetic undulator  

DOEpatents

This invention discloses an improved undulator comprising a plurality of electromagnet poles located along opposite sides of a particle beam axis with alternate north and south poles on each side of the beam to cause the beam to wiggle or undulate as it travels generally along the beam axis and permanent magnets spaced adjacent the electromagnetic poles on each side of the axis of said particle beam in an orientation sufficient to reduce the saturation of the electromagnet poles whereby the field strength of the electromagnet poles can be increased beyond the normal saturation levels of the electromagnetic poles. 4 figs.

Halbach, K.

1987-01-30

463

Hydrodynamic view of electrodynamics: energy rays and electromagnetic effective stress  

NASA Astrophysics Data System (ADS)

Energy rays ('photon trajectories') based upon the hydrodynamic formulation of electrodynamics are presented for time-dependent electromagnetic wave propagation. We derive Cauchy's equation of motion for the electromagnetic effective force governing the dynamics of energy rays. The effective force generated by the electromagnetic effective stress provides a surface force acting on the energy fluid element. For the head-on collision of two electromagnetic Gaussian pulses, the electromagnetic effective force, analogous to the role played by the quantum force in Bohmian mechanics, guides these non-crossing energy rays. For an electromagnetic pulse traveling from free space to a dielectric medium, the energy rays guided by the electromagnetic effective stress display reflection and refraction at the interface.

Chou, Chia-Chun; Wyatt, Robert E.

2011-06-01

464

Applications of the electromagnetic Helmholtz resonator*  

NASA Astrophysics Data System (ADS)

An electromagnetic Helmholtz resonator comprised of a capacitor with an aperture is investigated theoretically and experimentally. It is proposed that this resonance may be described using effective impedances describing the capacitor and aperture, similar to lumped element descriptions of the acoustic Helmholtz resonator. The dipole impedance of an electromagnetic aperture is derived and verified using the finite element method. Incorporating standard network relations, the aperture impedance can be used to calculate radiated power. Measurements of a capacitor demonstrates that the transmitted voltage through the capacitor is modified by induced charges. An induced voltage is introduced, and predictions agree with observations. Measurements of a capacitor with an aperture in the grounded plate indicate that induced currents cancel the imaginary impedance of the aperture, and double the real impedance. The observed impedance is close to predictions using the derived aperture impedance, confirming the utility of the aperture impedance in describing the system. The numerically obtained aperture electromagnetic fields are similar to the Birkeland current distribution and the cross polar cap potential in the Earth's polar ionosphere, motivating a model where the polar ionosphere is treated as an effective aperture. It is proposed that this effective aperture interacts with the capacitor formed between the Earth and ionosphere, creating an electromagnetic Helmholtz resonator. Predictions made with this model agree with measurements of transmitted power and phase velocity by FAST during a geomagnetic substorm, measurements of the Ionospheric Alfven Resonator, and oscillations recorded by ground based magnetometers. The same effective aperture behavior is expected in sunspots and polar coronal holes. A peak is predicted in Alfven wave power across the transition region for waves with a 5 min. period that delivers an average power over 100 W/m2 to the corona, sufficient to heat the quiet corona and launch the solar wind. Applied to sunspots, a minimum umbral temperature of 3750 K is predicted with a peak in transmitted power at 3 min., consistent with observations. A prototype electromagnetic guitar and associated methods to obtain music are also presented. These instruments replace the acoustic systems normally employed for musical instruments with electromagnetic equivalents and music samples are presented. *U.S. PATENTS PENDING 20070017344, 20070017345, 20070214940

Stoneback, Russell Alan

465

A bistable electromagnetically actuated rotary gate microvalve  

NASA Astrophysics Data System (ADS)

Two types of rotary gate microvalves are developed for flow modulation in microfluidic systems. These microvalves have been tested for an open flow rate of up to 100 sccm and operate under a differential pressure of 6 psig with flow modulation of up to 100. The microvalve consists of a suspended gate that rotates in the plane of the chip to regulate flow through the orifice. The gate is suspended by a novel fully compliant in-plane rotary bistable micromechanism (IPRBM) that advantageously constrains the gate in all degrees of freedom except for in-plane rotational motion. Multiple inlet/outlet orifices provide flexibility of operating the microvalve in three different flow configurations. The rotary gate microvalve is switched with an external electromagnetic actuator. The suspended gate is made of a soft magnetic material and its electromagnetic actuation is based on the operating principle of a variable-reluctance stepper motor.

Luharuka, Rajesh; Hesketh, Peter J.

2008-03-01

466

Development of a laced electromagnetic wiggler  

SciTech Connect

The laced electromagnetic wiggler is a new concept being developed to attain higher magnetic fields, shorter wavelengths, and larger gaps for the induction-linear accelerator, free-electron-laser (FEL) program. In the laced wiggler design, permanent magnets are located (''laced'') between the electromagnetic coils to increase the reverse-bias flux in the iron pole beyond that possible with only pole-edge (''side'') permanent magnets. This increase in reverse-bias flux allows wiggler operation at midplane magnetic field intensities comparable to those of a hybrid permanent magnet/steel wiggler, but with field adjustability over a specified range. The maximum field intensity and tuning range are selected, within limits, for specific design requirements. The authors have designed and tested a one-period prototype of this concept with promising results.

Christensen, T.C.; Burns, M.J.; Deis, G.A.; Parkison, C.D.; Halbach, K.

1988-03-01

467

Pulsed thrust measurements using electromagnetic calibration techniques  

SciTech Connect

A thrust stand for accurately measuring impulse bits, which ranged from 10-1000 {mu}N s using a noncontact electromagnetic calibration technique is described. In particular, a permanent magnet structure was designed to produce a uniform magnetic field, and a multiturn coil was made to produce a calibration force less than 10 mN. The electromagnetic calibration force for pulsed thrust measurements was linear to the coil current and changed less than 2.5% when the distance between the coil and magnet changed 6 mm. A pulsed plasma thruster was first tested on the thrust stand, and afterward five single impulse bits were measured to give a 310 {mu}N s average impulse bit. Uncertainty of the measured impulse bit was analyzed to evaluate the quality of the measurement and was found to be 10 {mu}N s with 95% credibility.

Tang Haibin; Shi Chenbo; Zhang Xin'ai; Zhang Zun; Cheng Jiao [School of Astronautics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China)

2011-03-15

468

Electromagnetic inverse applications for functional brain imaging  

SciTech Connect

This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). This project addresses an important mathematical and computational problem in functional brain imaging, namely the electromagnetic {open_quotes}inverse problem.{close_quotes} Electromagnetic brain imaging techniques, magnetoencephalography (MEG) and electroencephalography (EEG), are based on measurements of electrical potentials and magnetic fields at hundreds of locations outside the human head. The inverse problem is the estimation of the locations, magnitudes, and time-sources of electrical currents in the brain from surface measurements. This project extends recent progress on the inverse problem by combining the use of anatomical constraints derived from magnetic resonance imaging (MRI) with Bayesian and other novel algorithmic approaches. The results suggest that we can achieve significant improvements in the accuracy and robustness of inverse solutions by these two approaches.

Wood, C.C.

1997-10-01

469

Tour of the Electromagnetic Spectrum (EMS) Videos  

NSDL National Science Digital Library

These videos introduce middle- and high school-age learners to the electromagnetic spectrum. The product consists of 8 animations including an introduction to electromagnetic waves and one animation for each wavelength of the EM spectrum (Radio, Microwave, Infrared, Visible, Ultraviolet, X-Rays and Gamma Rays). Each wavelength of the EM spectrum offers a construct to illustrate and teach about NASA sensors, missions, and science. Emphasis is placed on relevant science, such as lunar exploration, and hot science topics, such as climate change. The examples and narrative for each wavelength animation build on the learnersâ prior knowledge then introduces examples from NASA missions. These examples explore the use of spectral analysis and visualizations that help scientists make discoveries about the world around us using EM waves.

Benesch, Troy

2009-01-01

470

Development of a laced electromagnetic wiggler  

SciTech Connect

The laced electromagnetic wiggler is a new concept being developed to attain higher magnetic fields, shorter wavelengths, and larger gaps for the induction-linear accelerator, free-electron-laser (FEL) program. In the laced wiggler design, permanent magnets are located (''laced'') between the electromagnetic coils to increase the reverse-bias flux in the iron pole beyond that possible with only pole-edge (''side'') permanent magnets. This increase in reverse-bias flux allows wiggler operation at midplane magnetic field intensities comparable to those of a hybrid permanent magnet/steel wiggler, but with field adjustability over a specified range. The maximum field intensity and tuning range are selected, within limits, for specific design requirements. We have designed and tested a one-period prototype of this concept with promising results.

Christensen, T.C.; Burns, M.J.; Deis, G.A.; Parkison, C.D.; Prosnitz, D.; Halbach, K.

1987-01-01

471

Fluidic electrodynamics: Approach to electromagnetic propulsion  

SciTech Connect

We report on a new methodological approach to electrodynamics based on a fluidic viewpoint. We develop a systematic approach establishing analogies between physical magnitudes and isomorphism (structure-preserving mappings) between systems of equations. This methodological approach allows us to give a general expression for the hydromotive force, thus re-obtaining the Navier-Stokes equation departing from the appropriate electromotive force. From this ground we offer a fluidic approach to different kinds of issues with interest in propulsion, e.g., the force exerted by a charged particle on a body carrying current; the magnetic force between two parallel currents; the Magnus's force. It is shown how the intermingle between the fluid vector fields and electromagnetic fields leads to new insights on their dynamics. The new concepts introduced in this work suggest possible applications to electromagnetic (EM) propulsion devices and the mastery of the principles of producing electric fields of required configuration in plasma medium.

Martins, Alexandre A.; Pinheiro, Mario J. [Institute for Plasmas and Nuclear Fusion and Instituto Superior Tecnico Lisboa, Portugal 351.1.21.841.92.43 (Portugal); Department of Physics and Institute for Plasmas and Nuclear Fusion and Instituto Superior Tecnico Lisboa, Portugal 351.1.21.841.93.22 (Portugal)

2009-03-16

472

Electromagnetic Counterparts to Supermassive Black Hole Mergers  

NASA Astrophysics Data System (ADS)

Future space-based gravitational-wave observations will provide an entirely new channel of information about the massive black holes marking the hearts of merging galaxies. The complementarity of gravitational-wave information with that from existing and future electromagnetic observations may enable strong astrophysical inferences to be drawn from future multimessenger observations, if they can be achieved. We discuss numerical simulations of transient electromagnetic signatures associated with massive black hole mergers, which include strong X-ray components. If such transients exist, the relative scarcity of bright X-ray sources, may lead to greater opportunities for multimessenger associations even for relatively poorly located gravitational-wave events. Understanding this possibility also requires better characterization of the transient X-ray sky.

Baker, John G.; Giacomazzo, B.; Kanner, J.; Kelly, B. J.; Schnittman, J.

2013-04-01

473

Coherent spin control by electromagnetic vacuum fluctuations  

SciTech Connect

In coherent control, electromagnetic vacuum fluctuations usually cause coherence loss through irreversible spontaneous emission. However, since the dissipation via emission is essentially due to correlation of the fluctuations, when emission ends in a superposition of multiple final states, correlation between different pathways may build up if the 'which way' information is not fully resolved (i.e., the emission spectrum is broader than the transition energy range). Such correlation can be exploited for spin-flip control in a {Lambda}-type three-level system, which manifests itself as an all-optical spin echo in nonlinear optics with two orders of optical fields saved as compared with stimulated Raman processes. This finding represents a class of optical nonlinearity induced by electromagnetic vacuum fluctuations.

Wang Jing [Department of Physics, Chinese University of Hong Kong, Shatin, N.T. (Hong Kong); Department of Physics, Tsinghua University, Beijing 100084 (China); Liu Renbao [Department of Physics, Chinese University of Hong Kong, Shatin, N.T. (Hong Kong); Zhu Bangfen [Department of Physics, Tsinghua University, Beijing 100084 (China); Institute of Advanced Study, Tsinghua University, Beijing 100084 (China); Sham, L. J. [Department of Physics, University of California-San Diego, La Jolla, California 92093-0319 (United States); Steel, D. G. [H. M. Randall Laboratory of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2011-05-15

474

Electromagnetic radiation absorbers and modulators comprising polyaniline  

DOEpatents

A composition for absorbing electromagnetic radiation, wherein said electromagnetic radiation possesses a wavelength generally in the range of from about 1000 Angstroms to about 50 meters, wherein said composition comprises a polyaniline composition of the formula ##STR1## where y can be equal to or greater than zero, and R.sup.1 and R.sup.2 are independently selected from the group containing of H, --OCH.sub.3, --CH.sub.3, --F, --Cl, --Br, --I, NR.sup.3 .sub.2, --NHCOR.sup.3, --OH, --O.sup.-, SR.sup.3, --OCOR.sup.3, --NO.sub.2, --COOH, --COOR.sup.3, --COR.sup.3, --CHO, and --CN, where R.sup.3 is a C.sub.1 to C.sub.8 alkyl, aryl or aralkyl group.

Epstein, Arthur J. (Bexley, OH); Ginder, John M. (Columbus, OH); Roe, Mitchell G. (Columbus, OH); Hajiseyedjavadi, Hamid (Columbus, OH)

1992-01-01

475

Radiated fields from an electromagnetic pulse simulator  

NASA Astrophysics Data System (ADS)

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.

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

476

Electromagnetically Induced Transparency for X Rays  

SciTech Connect

Electromagnetically induced transparency is predicted for x rays in laser-dressed neon gas. The x-ray photoabsorption cross section and polarizability near the Ne K edge are calculated using an ab initio theory suitable for optical strong-field problems. The laser wavelength is tuned close to the transition between 1s{sup -1}3s and 1s{sup -1}3p ({approx}800 nm). The minimum laser intensity required to observe electromagnetically induced transparency is of the order of 10{sup 12} W/cm{sup 2}. The ab initio results are discussed in terms of an exactly solvable three-level model. This work opens new opportunities for research with ultrafast x-ray sources.

Buth, Christian; Santra, Robin; Young, Linda [Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2007-06-22

477

Electromagnetic baryon form factors from holographic QCD  

NASA Astrophysics Data System (ADS)

In the holographic model of QCD suggested by Sakai and Sugimoto, baryons are chiral solitons sourced by D4 instantons in bulk of size 1/(?)1/2 with ? = g2Nc. We quantize the D4 instanton semiclassically using hbar = 1/(Nc?) and non-rigid constraints on the vector mesons. The holographic baryon is a small chiral bag in the holographic direction with a Cheshire cat smile. The vector-baryon interactions occur at the core boundary of the instanton in D4. They are strong and of order 1/(hbar)1/2. To order hbar0 the electromagnetic current is entirely encoded on the core boundary and vector-meson dominated. To this order, the electromagnetic charge radius is of order ?0. The meson contribution to the baryon magnetic moments sums identically to the core contribution. The proton and neutron magnetic moment are tied by a model independent relation similar to the one observed in the Skyrme model.

Kim, Keun-Young; Zahed, Ismail

2008-09-01

478

Vibration based electromagnetic micropower generator on silicon  

NASA Astrophysics Data System (ADS)

This paper discusses the theory, design and simulation of electromagnetic micropower generators with electroplated micromagnets. The power generators are fabricated using standard microelectromechanical system processing techniques. Electromagnetic two-dimensional finite element anlysis simulations are used to determine voltage and power that can be generated from different designs. This paper reports a maximum voltage and power of 55 mV and 70 ?W for the first design, incorporating microfabricated two-layer Cu coils on a Si paddle vibrating between two sets of oppositely polarized electroplated Co50Pt50 face centered tetragonal phase hard magnets. A peak voltage and power of 950 mV and 85 ?W are obtained for the second design, which includes electroplated Ni45Fe55 as a soft magnetic layer underneath the hard magnets. The volume of the device is about 30 mm3.

Kulkarni, Santosh; Roy, Saibal; O'Donnell, Terence; Beeby, Steve; Tudor, John

2006-04-01

479

Ionization in a quantized electromagnetic field  

SciTech Connect

An analytical expression for a matrix element of the transition from a bound state of an electron in an atom to continuum states is obtained by solving the problem of interaction of the electron with a quantized electromagnetic field. This expression is used to derive formulas for the photoelectron spectrum and the rate of ionization of the simplest model atomic system upon absorption of an arbitrary number of photons. The expressions derived are analyzed and compared with the corresponding relationships obtained via other approaches. It is demonstrated that there are differences as compared to the case of the classical field. In particular, the photoelectron spectrum exhibits dips due to the destructive interference of the transition amplitudes in the quantized electromagnetic field.

Gonoskov, I. A., E-mail: gonoskov@ufp.appl.sci-nnov.ru; Vugalter, G. A.; Mironov, V. A. [Russian Academy of Sciences, Institute of Applied Physics (Russian Federation)

2007-12-15

480

Storage of electromagnetic field energy in matter  

NASA Astrophysics Data System (ADS)

The partitioning, uniqueness and form of field energy stored in matter, and its properties as a state function, is established. Consequently, the first and second laws apply to the nonfield and field parts of the internal energy as separate entities. This provides a bridge between thermodynamics and the classical theory of electromagnetism. Presentation of the temperature as the sum of nonfield and field contributions is used to establish field dependent barriers to temperature decrease toward the absolute zero, and the existence of field induced temperature jumps. These temperature jumps appear at the instant the field is switched on, or turned off. The partitioning of field and nonfield energies is illustrated for a specific case of an ideal gas, and the heat absorbed by the field is derived in terms of difference in adiabatic magnetization. Finally, the current, restrictive, form of electromagnetic field energy density is redefined with respect to the effect of field energy stored outside the system boundaries.

Zimmels, Y.

2002-11-01

481

Electromagnetic pulse and the electric power network  

SciTech Connect

This paper defines the nuclear electromagnetic pulse (EMP) - electric power system interaction problem. A description of high altitude EMP (HEMP) characteristics, source region EMP (SREMP) characteristics, and magnetohydrodynamics EMP (MHD-EMP) characteristics are presented. The results of initial calculations of EMP induced surges on electric power transmission and distribution lines are presented and compared with lightning induced surges. Potential EMP impacts on electric power systems are discussed, and an overview of the Department of Energy (DOE) EMP research program is presented.

Klein, K.W.; Barnes, P.R.; Zaininger, H.W.

1984-01-01

482

BPS electromagnetic waves on giant gravitons  

Microsoft Academic Search

We find new 1\\/8-BPS giant graviton solutions in AdS5 × S5, carrying three angular momenta along S5, and investigate their properties. Especially, we show that nonzero worldvolume gauge fields are admitted preserving supersymmetry. These gauge field modes can be viewed as electromagnetic waves along the compact D3 brane, whose Poynting vector contributes to the BPS angular momenta. We also analyze

Seok Kim; Kimyeong Lee

2005-01-01

483

Electromagnetic linear actuators with inductive position sensing  

Microsoft Academic Search

Magnetically driven linear micro-actuators with 1 mN output force and hundreds of microns of total travel have been realized using LIGA-like processing techniques. These devices are driven at resonance frequencies of around 350 Hz and exhibit quality factors of about 300 in air. Exploiting wire-wound electromagnets, 300 ?m resonant displacements have been demonstrated with drive signal currents of about 1

H Guckel; T Earles; J Klein; J. D Zook; T Ohnstein

1996-01-01

484

Cognitive Effects of Electromagnetic Fields in Humans  

Microsoft Academic Search

\\u000a Electromagnetic fields interact with human tissue in a number of ways, depending on power level and frequency, and have been\\u000a long suspected by some to give rise to harmful effects. In particular, the use of a mobile phone against the head has aroused\\u000a suspicions of various cognitive effects. Accordingly, there have been a large number of studies of behavioural effects

Alan W. Preece

485

Electromagnetic Standing Waves and Ball Lightning  

Microsoft Academic Search

BY now it is well known1-3 that charged particles moving in harmonically oscillating vacuum electromagnetic fields can be subject to time-average forces which establish a virtual potential minimum for them. The matter takes on a different aspect when the number of particles is so large as to form a highly conducting plasma, as in Kapitza's theory of ball lightning4. Then,

Lewi Tonks

1960-01-01

486

Metamaterial transparency induced by cooperative electromagnetic interactions.  

PubMed

We propose a cooperative asymmetry-induced transparency, CAIT, formed by collective excitations in metamaterial arrays of discrete resonators. CAIT can display a sharp transmission resonance even when the constituent resonators individually exhibit broad resonances. We further show how dynamically reconfiguring the metamaterial allows one to actively control the transparency. While reminiscent of electromagnetically induced transparency, which can be described by independent emitters, CAIT relies on a cooperative response resulting from strong radiative couplings between the resonators. PMID:24138271

Jenkins, Stewart D; Ruostekoski, Janne

2013-09-30

487

Simulation and Visualisation for Electromagnetic Nondestructive Evaluation  

Microsoft Academic Search

This paper reviews the state-of-the art of modelling, simulation and visualisation and reviews the recent development of modelling, simulation and visualisation software for Nondestructive Evaluation (NDE). Simulation and visualisation can assist in the design and development of electromagnetic sensing and imaging techniques and systems for nondestructive testing, feature extraction and inverse problems for quantitative nondestructive evaluation. After reviewing the state-of-the

Anthony Simm; Ilham Zainal Abidin; Gui Yun Tian; Wai Lok Woo

2010-01-01

488

Radiation damage due to electromagnetic showers  

Microsoft Academic Search

Radiation-induced damage due to atomic displacements is essential to correctly predict the behavior of materials in nuclear reactors and at charged-particle accelerators. Traditionally the damage due to hadrons was of major interest. The recent increased interest in high-energy lepton colliders gave rise to the problem of prediction of radiation damage due to electromagnetic showers in a wide energy range--from a

Igor Rakhno; Nikolai Mokhov; Sergei Striganov

2008-01-01

489

Bobbing and kicks in electromagnetism and gravity  

SciTech Connect

We study systems analogous to binary black holes with spin in order to gain some insight into the origin and nature of 'bobbing' motion and 'kicks' that occur in this system. Our basic tool is a general formalism for describing the motion of extended test bodies in an external electromagnetic field in curved spacetime and possibly subject to other forces. We first show that bobbing of exactly the type as observed in numerical simulations of the binary black hole system occurs in a simple system consisting of two spinning balls connected by an elastic band in flat spacetime. This bobbing may be understood as arising from the difference between a spinning body's 'lab frame centroid' and its true center of mass, and is purely 'kinematical' in the sense that it will appear regardless of the forces holding two spinning bodies in orbit. Next, we develop precise rules for relating the motion of charged bodies in a stationary external electromagnetic field in flat spacetime with the motion of bodies in a weakly curved stationary spacetime. We then consider the system consisting of two orbiting charges with magnetic dipole moment and spin at a level of approximation corresponding to 1.5 post-Newtonian order. Here we find that considerable amounts of momentum are exchanged between the bodies and the electromagnetic field; however, the bodies store this momentum entirely as ''hidden'' mechanical momentum, so that the interchange does not give rise to any net bobbing. The net bobbing that does occur is due solely to the kinematical spin effect, and we therefore argue that the net bobbing of the electromagnetic binary is not associated with possible kicks. We believe that this conclusion holds in the gravitational case as well.

Gralla, Samuel E.; Harte, Abraham I.; Wald, Robert M. [Enrico Fermi Institute and Department of Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, Illinois 60637 (United States)

2010-05-15

490

Exact quantization of a paraxial electromagnetic field  

SciTech Connect

A nonperturbative quantization of a paraxial electromagnetic field is achieved via a generalized dispersion relation imposed on the longitudinal and the transverse components of the photon wave vector. This theoretical formalism yields a seamless transition between the paraxial- and the Maxwell-equation solutions. This obviates the need to introduce either ad hoc or perturbatively defined field operators. Moreover, our (exact) formalism remains valid beyond the quasimonochromatic paraxial limit.

Aiello, A.; Woerdman, J. P. [Huygens Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden (Netherlands)

2005-12-15

491

A new look at electromagnetic field theory  

Microsoft Academic Search

The most general expression of electromagnetic theory is examined in the light of (1) Faraday's interpretation of the field\\u000a as a potentiality for the force of charged matter to act upon a test body, and (2) Einstein's view of the field equations\\u000a as an example of a covariant expression of special relativity. Faraday's original interpretation, in which all physical variables

Mendel Sachs

1980-01-01

492

Rectangular Pulsed Laser-Electromagnetic Hybrid Accelerator  

SciTech Connect

Experimental investigation of impulse-bit and propellant consumption rate, or mass shot, per single pulse discharge was conducted to characterize the thrust performance of the rectangular laser-electromagnetic hybrid acceleration thruster with various propellant materials. From the result, alumina propellant showed significantly superior performance. The largest values of the measured impulse-bit, specific impulse and thrust efficiency were 49 {mu}Nsec, 6,200 sec and 22%, respectively.

Kishida, Yoshiaki; Katayama, Masahiro; Horisawa, Hideyuki [Department of Aeronautical and Astronautical Engineering, Tokai University Hiratsuka, Kanagawa, 259-1292 (Japan)

2010-10-13

493

Electromagnetic Casimir forces in elliptic cylinder geometries  

NASA Astrophysics Data System (ADS)

The scattering theory approach makes it possible to carry out exact calculations of Casimir energies in any geometry for which the scattering T-matrix and a partial wave expansion of the free Green’s function are available. We implement this program for the case of a perfectly conducting elliptic cylinder, thereby completing the set of geometries where electromagnetic scattering is separable. Particular emphasis is placed on the case of zero radius, where the elliptic cylinder reduces to a strip.

Graham, Noah

2013-05-01

494

Electromagnetic energy and momentum in moving media  

Microsoft Academic Search

The problem of the electromagnetic energy-momentum tensor is among the oldest\\u000aand the most controversial in macroscopic electrodynamics. In the center of the\\u000aissue is a dispute about the Minkowski and the Abraham tensors for moving\\u000amedia. An overview of the current situation is presented. After putting the\\u000adiscussion into a general Lagrange-Noether framework, the Minkowski tensor is\\u000arecovered as

Yuri N. Obukhov

2008-01-01

495

Applications of coilgun electromagnetic propulsion technology  

Microsoft Academic Search

Exciting and important applications of pulsed power and high voltage technology are found in the growing area of electromagnetic launch and propulsion. These applications include small-scale, precision staging devices (magnetically driven), low-speed, large mass catapult launchers, low-speed and high-speed trains, high-speed, long-range fire support naval guns, and the futuristic application of high-speed, direct satellite launch to space. The force requirements

R. J. Kaye; Bob N. Turman; Steven L. Shope

2002-01-01

496

The quantum effects of electromagnetic fluxes  

Microsoft Academic Search

This paper is a review of the problem of the observable action of enclosed electromagnetic fluxes on the quantum-mechanical state of charged particles, known as the Aharonov-Bohm effect. The authors first describe the quantum effects of the fluxes in the quasiclassical approximation, and discuss their relation with basic quantum-mechanical principles. Then they examine the influence of modeling assumptions on the

S. Olariu; I. Iovitzu Popescu

1985-01-01

497

The electromagnetic calorimeter of the NOMAD experiment  

Microsoft Academic Search

A description is given of the NOMAD electromagnetic calorimeter, consisting of 875 lead-glass counters read out by two-stage photomultipliers and a low noise electronic chain. The detector operates in a 0.4 T magnetic field transverse to the counter axis. The paper discusses the design criteria, the lead-glass characteristics, the properties of the read out chain and provides a summary of

D. Autiero; M. Baldo-Ceolin; G. Barichello; V. Bianchi-Bonaiti; F. Bobisut; A. Cardini; P. W. Cattaneo; V. Cavasinni; C. Conta; T. Del Prete; A. De Santo; L. Di Lella; R. Ferrari; V. Flaminio; M. Fraternali; D. Gibin; S. N. Gninenko; A. Guglielmi; E. Iacopini; A. V. Kovzelev; L. La Rotonda; A. Lanza; M. Laveder; C. Lazzeroni; M. Livan; M. Mezzetto; D. Orestano; F. Pastore; E. Pennacchio; R. Petti; G. Polesello; G. Renzoni; A. Rimoldi; C. Roda; A. Sconza; C. Sobczynski; M. Valdata-Nappi; M. Vascon; V. Vercesi; L. Visentin; S. A. Volkov

1996-01-01

498

Photino bremsstrahlung in intense electromagnetic fields  

NASA Astrophysics Data System (ADS)

We calculate the probability for the emission of a pair of photinos by an electron moving in a background electromagnetic field. The rate of the process e -> e?~?~ is estimated at different values of the field strength and electron energies. Comparing the cooling rate of some astrophysical objects via photino bremsstrahlung with another competing energy-loss mechanism we find new constraints on the selectron massesMe~R =Me~L >= 89.4 GeV.

Kurilin, Alexander V.; Ternov, Aleksey I.

1996-02-01

499

Phenomenology of the deuteron electromagnetic form factors  

Microsoft Academic Search

:   A rigorous extraction of the deuteron charge form factors from tensor polarization data in elastic electron-deuteron scattering,\\u000a at given values of the 4-momentum transfer, is presented. Then the world data for elastic electron-deuteron scattering is\\u000a used to parameterize, in three different ways, the three electromagnetic form factors of the deuteron in the 4-momentum transfer\\u000a range 0-7 fm?1. This procedure

David Abbott; Abdellah Ahmidouch; H. Anklin; J. Arvieux; James P. Ball; Shelton Beedoe; Elizabeth Beise; Louis Bimbot; Werner Boeglin; Herbert Breuer; Roger Carlini; Nicholas Chant; Samuel Danagoulian; K. Dow; Jean-Eric Ducret; Jim Dunne; Lars Ewell; L. Eyraud; C. Furget; M. Garçcon; Ron Gilman; Charles Glashausser; Paul Gueye; Kenneth Gustafsson; Kawtar Hafidi; A. Honegger; J. Jourdan; Serge Kox; Gerfried Kumbartzki; L. Lu; Allison Lung; Pete Markowitz; Justin McIntyre; David Meekins; F. Merchez; Joseph Mitchell; R. Mohring; S. Mtingwa; H. Mrktchyan; D. Pitz; Liming Qin; Ronald Ransome; J.-S. Réal; Philip Roos; Paul Rutt; Reyad Sawafta; Stepan Stepanyan; Raphael Tieulent; E. Tomasi-Gustafsson; William Turchinetz; K. Vansyoc; J. Volmer; E. Voutier; Claude Williamson; Stephen Wood; Chen Yan; Jianguo Zhao; W. Zhao

2000-01-01

500

Modeling of electromagnetically formed sheet metal  

Microsoft Academic Search

The intent of this paper is to show that a two-dimensional (2D) arbitrary Lagrangian Eulerian (ALE) finite-difference computer code can accurately predict the dynamics of the electromagnetic sheet metal forming process. The challenging aspect of simulating the deformation of thin metal parts which have been loaded by magnetic forces is solving a highly coupled system of partial differential equations. The

Gregg K Fenton; Glenn S Daehn

1998-01-01