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Last update: August 15, 2014.
1

Electromagnetism.  

National Technical Information Service (NTIS)

This program demonstrates the characteristics of electromagnetism with iron filings and a compass. It shows the left-hand rule for determining current flow in an electromagnet. It illustrates the use of a dot and a cross to designate current flow.

1994-01-01

2

Electromagnets  

NSDL National Science Digital Library

This is an activity about the properties of electromagnets, which is a crucial underpinning for understanding how magnetic fields are generated in nature, in the surface of the Sun, and in the interior of Earth. Learners will create an electromagnet by letting an electric current flow through a wire to generate a magnetic field, which is then detected using a compass. This activity requires a thin insulated wire, pencil, battery, compass and paper clips. This is Activity 2 of the Magnetism and Electromagnetism teachers guide.

3

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

4

Electromagnetic Suspension.  

National Technical Information Service (NTIS)

The electromagnetic suspension suggested differs from known suspensions in that its rotor is made in the form of a rod placed between the poles of the electromagnets of an n-phase system. This invention can be used in gravimetry and gyroscopic devices. (A...

B. V. Bolotov L. Z. Piven

1973-01-01

5

Electromagnetic Attraction.  

ERIC Educational Resources Information Center

Three activities involving electromagnetism are presented. Discussed are investigations involving the construction of an electromagnet, the effect of the number of turns of wire in the magnet, and the effect of the number of batteries in the circuit. Extension activities are suggested. (CW)

Milson, James L.

1990-01-01

6

Virtual Electromagnet  

NSDL National Science Digital Library

This is an interactive online activity, in which learners equip a virtual electromagnet and see how many iron filings it can pick up. Learners change various characteristics of the electromagnet including the number of windings, the gage of the wire, the current type (AC or DC), the material used in the wire, and the voltage on the power supply.

Regents, The U.

2014-01-01

7

Electromagnetic fasteners  

DOEpatents

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

8

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

9

Electromagnetic Math  

NSDL National Science Digital Library

This book offers an introduction to the electromagnetic spectrum using examples of data from a variety of NASA missions and satellite technologies. The 84 problem sets included allow students to explore the concepts of waves, wavelength, frequency, and speed; the Doppler Shift; light; and the energy carried by photons in various bands of the spectrum. Extensive background information is provided which describes the nature of electromagnetic radiation.

10

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

11

Creating an Electromagnet  

NSDL National Science Digital Library

Student teams investigate the properties of electromagnets. They create their own small electromagnet and experiment with ways to change its strength to pick up more paper clips. Students learn about ways that engineers use electromagnets in everyday applications.

Integrated Teaching And Learning Program

12

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

13

Electromagnetic valve  

US Patent & Trademark Office Database

In an electromagnetic valve, a composite valve case has a cylindrical hollow and a composite valve body formed in spool shape is slidably housed in the cylindrical hollow. The composite valve body has not only an inherent valve function for changing fluid path area according to its movement in the cylindrical hollow but also an armature function for constituting a magnetic circuit. The composite valve case has not only a cylinder function for allowing the valve body to slidably move but also a stator function for constituting a magnetic circuit. The composite valve body and the composite valve case are made of soft magnetic material and are provided at their surfaces with thin hardened layers formed by surface or heat treatment.

2003-12-30

14

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

15

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

16

Electromagnetic environmental effects compendium  

NASA Astrophysics Data System (ADS)

This report summarizes the electromagnetic environmental effects (E3) program of the U.S. Army Communications-Electronics Command (CECOM). The report includes background information on CECOM's role in the Army E3 program, presents the approach used to identify the electromagnetic environment, summarizes E3 criteria (i.e., the CECOM model electromagnetic environment), and provides a sample E3 assessment. The report also discusses electromagnetic trends and their implications.

Brockel, Kenneth H.; Cofield, David; Deallaume, William; Gorr, Lanny; Major, Paul A.

1993-08-01

17

Electromagnetic particle simulation codes  

Microsoft Academic Search

Electromagnetic particle simulations solve the full set of Maxwell's equations. They thus include the effects of self-consistent electric and magnetic fields, magnetic induction, and electromagnetic radiation. The algorithms for an electromagnetic code which works directly with the electric and magnetic fields are described. The fields and current are separated into transverse and longitudinal components. The transverse E and B fields

P. L. Pritchett

1985-01-01

18

The electromagnetic spike solutions  

NASA Astrophysics Data System (ADS)

The aim of this paper is to use the existing relation between polarized electromagnetic Gowdy spacetimes and vacuum Gowdy spacetimes to find explicit solutions for electromagnetic spikes by a procedure which has been developed by one of the authors for gravitational spikes. We present new inhomogeneous solutions which we call the EME and MEM electromagnetic spike solutions.

Nungesser, Ernesto; Lim, Woei Chet

2013-12-01

19

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

20

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

21

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.

22

Electromagnetic structure of pion  

SciTech Connect

In this work, we analyze the electromagnetic structure of the pion, an elementary particle composed by a quark-antiquark bound state, by considering the calculation of its electromagnetic radius and its electromagnetic form factor in low and intermediate energy range. Such observables are determined by means of a theoretical model that takes into account the constituent quark and antiquark of the pion, in the formalism of the light-front field theory. In particular, it is considered a nonsymmetrical vertex for such a model, in which we have calculated the electromagnetic form factor of the pion in an optimized way, by varying its regulator mass, so that we can obtain the best value for the pion electromagnetic radius when compared with the experimental one. The theoretical calculations are also compared with the most recent experimental data involving the pion electromagnetic form factor and the results show very good agreement.

Mello, Clayton S.; Cruz Filho, Jose P.; Da Silva, Edson O.; El-Bennich, Bruno; De Melo, J. P.; Filho, Victo S. [Laboratorio de Fisica Teorica e Computacional (LFTC), Universidade Cruzeiro do Sul, 01506-000, Sao Paulo (Brazil)

2013-03-25

23

How Strong are Electromagnets?  

NSDL National Science Digital Library

This is an activity about electromagnetism. Using a battery and a length of wire, learners will construct an electromagnet and investigate the number of paperclips the electromagnet can hold for an electromagnet with twenty loops of wire versus one with forty loops of wire. A six to twelve volt battery, a large nail or metal rod, and insulated wire are required for this activity. This is the fourth activity in the Exploring the Earth's Magnetic Field: An IMAGE Satellite Guide to the Magnetosphere educators guide.

24

The Electromagnetic Spectrum  

NSDL National Science Digital Library

This is a lesson about the electromagnetic spectrum. Learners will read two pages of information about the electromagnetic spectrum and answer questions in an accompanying worksheet. This activity is from the Stanford Solar Center's All About the Sun: Sun and Stars activity guide for Grades 5-8 and can also accompany the Stanford Solar Center's Build Your Own Spectroscope activity.

25

Electromagnetic compatibility overview  

NASA Technical Reports Server (NTRS)

An assessment of the electromagnetic compatibility impact of the Satellite Power System is discussed. The discussion is divided into two parts: determination of the emission expected from SPS including their spatial and spectral distributions, and evaluation of the impact of such emissions on electromagnetic systems including considerations of means for mitigating effects.

Davis, K. C.

1980-01-01

26

Electromagnetic Analysis: Concrete Results  

Microsoft Academic Search

Abstract Although the possibility of attacking smart - cards by analyz - ing their electromagnetic power radiation repeatedly appears in research papers, all accessible references evade the essence of reporting conclusive experiments where actual cryptographic algorithms such as des or rsa were successfully attacked This work describes electromagnetic experiments conducted on three dif - ferent cmos chips, featuring di erent

Karine Gandolfi; Christophe Mourtel; Francis Olivier

2001-01-01

27

Electromagnetic shunt damping  

Microsoft Academic Search

A method for electromagnetic shunt damping (EMSD) is presented in this paper. Compared to piezoelectric shunt damping, the proposed EMSD vibration controller has a number of benefits. It requires small shunt voltages, can provide large stroke and can dampen larger mechanical structures. A passive control strategy is validated through experimentation on a simple electromagnetic mass-spring-damper system. Theoretical results are also

S. Behrens; A. J. Fleming; S. O. Reza Moheimani

2003-01-01

28

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

29

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

30

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

31

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

32

Electromagnetic particle simulation codes  

Microsoft Academic Search

Electromagnetic particle simulations solve the full set of Maxwell's equations. They thus include the effects of self-consistent\\u000a electric and magnetic fields, magnetic induction, and electromagnetic radiation. The algorithms for an electromagnetic code\\u000a which works directly with the electric and magnetic fields are described. The fields and current are separated into transverse\\u000a and longitudinal components. The transverse \\u000a $$\\\\underset{\\\\raise0.3em\\\\hbox{$\\\\smash{\\\\scriptscriptstyle\\\\thicksim}$}}{E} $$\\u000a and \\u000a $$\\\\underset{\\\\raise0.3em\\\\hbox{$\\\\smash{\\\\scriptscriptstyle\\\\thicksim}$}}{B}

P. L. Pritchett

1985-01-01

33

The ALICE Electromagnetic Calorimeters  

NASA Astrophysics Data System (ADS)

ALICE is the general purpose experiment at the LHC dedicated to the study of heavy ion collisions. ALICE includes two different electromagnetic calorimeters: a high resolution, modest acceptance PHoton Spectrometer (PHOS) and a large acceptance, moderate resolution electromagnetic calorimeter (EMCal). The electromagnetic calorimeters are designed to trigger on high energy gamma-rays and jets, and to enhance the capabilities of ALICE for these measurements. The PHOS is a PbWo4 crystal calorimeter while the EMCal is a Ph/Scintillator sampling shish-kebab type calorimeter. The PHOS and EMCal construction, readout, and performance are described.

Awes, Terry C.

2012-08-01

34

High frequency electromagnetic tomography  

SciTech Connect

An experiment was conducted in G Tunnel at the Nevada Test Site to evaluate high frequency electromagnetic tomography as a candidate for in situ monitoring of hydrology in the near field of a heater placed in densely welded tuff. Tomographs of 200 MHz electromagnetic permittivity were made for several planes between boreholes. Data were taken before the heater was turned on, during heating and during cooldown of the rockmass. This data is interpreted to yield maps of changes in water content of the rockmass as a function of time. This interpretation is based on laboratory measurement of electromagnetic permittivity as a function of water content for densely welded tuff. 8 refs., 6 figs.

Daily, W.; Ramirez, A.; Ueng, T.; Latorre, R.

1989-09-01

35

Electromagnetically Driven Flux Compression.  

National Technical Information Service (NTIS)

Electromagnetically driven flux compression (EMC) devices are developed with a view to applications for experiments with megagauss fields, in particular for a study of magnetic bremsstrahlung. Fields of the order of 1.3 MG are reproducibly generated by me...

D. Kachilla, F. Herlach, T. Erber

1969-01-01

36

Electromagnetic Field Probes.  

National Technical Information Service (NTIS)

The report summarizes activities during the first quarter of a program directed to the development of probes and techniques for measurement of electromagnetic radiation in shielded enclosures over the 20 to 200 MHz frequency range. Studies were made of te...

G. W. Bechtold J. L. Birchfield R. D. Wetherington

1972-01-01

37

Electromagnetic structure of nuclei  

NASA Astrophysics Data System (ADS)

A brief review is given of selected topics in the electromagnetic structure of nucleons and nuclei for which significant progress was obtained in the two years since the last meeting in this series at Steamboat Springs Colorado.

Arnold, R. G.

1986-10-01

38

Electromagnetic structure of nuclei  

SciTech Connect

A brief review is given of selected topics in the electromagnetic structure of nucleons and nuclei for which significant progress was obtained in the two years since the last meeting in this series at Steamboat Springs Colorado.

Arnold, R.G.

1986-10-15

39

The Electromagnetic Spectrum  

NSDL National Science Digital Library

This interactive, online module reviews the basics of the the electromagnetic spectrum and makes the connection between radiation theory and the images we get from weather satellites. Students will learn about: the electromagnetic spectrum; electromagnetic waves; the electromagnetic spectrum and radiation theory; and how satellite radiometers "see" different sections of the spectrum. The module is part of an online course for grades 7-12 in satellite meteorology, which includes 10 interactive modules. The site also includes lesson plans developed by teachers and links to related resources. Each module is designed to serve as a stand-alone lesson, however, a sequential approach is recommended. Designed to challenge students through the end of 12th grade, middle school teachers and students may choose to skim or skip a few sections.

40

Electromagnetism in the Movies.  

ERIC Educational Resources Information Center

Describes how the authors used portions of popular movies to help students review concepts related to electromagnetism. Movies used and concepts covered in the review are listed, and a sample activity is described. (WRM)

Everitt, Lori R.; Patterson, Evelyn T.

1999-01-01

41

Electromagnetically Tunable Fluids.  

National Technical Information Service (NTIS)

The overarching goal of this project was to exploit the transport properties at colloidal and microfluidic dimensions to controllably alter the high-frequency electromagnetic material properties at the macro level. This was to achieve multifunctionality a...

D. Lagoudas G. H. Huff J. Boyd M. A. Bevan Z. Ounaies

2011-01-01

42

Research in Electromagnetic Scattering.  

National Technical Information Service (NTIS)

In the main area of Frequency-Domain Electromagnetics, we made significant accomplishments in the sub-areas of Scattering-Matrix Analysis of periodic Arrays, Bandwidth and Quality Factor of Antennas, Supergain Arrays, and Surface Integral Equations. Yaghj...

A. Yaghjian

2006-01-01

43

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

44

A Compact Electromagnetic Accelerator.  

National Technical Information Service (NTIS)

An electromagnetic pellet accelerator for the injection of glass beads into a plasma accelerator is used to simulate cometary dust for collection method development. The accelerator is described and a schematic diagram given. Its operational characteristi...

E. Igenbergs H. Kuczera P. Lell

1980-01-01

45

Solar Nantenna Electromagnetic Collectors.  

National Technical Information Service (NTIS)

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...

D. Slafe D. K. Kotter P. Pinhero S. D. Novack

2008-01-01

46

An opening electromagnetic transducer  

NASA Astrophysics Data System (ADS)

Tubular solenoids have been widely used without any change since an electrical wire was discovered to create magnetic fields by Hans Christian Oersted in 1820 and thereby the wire was first coiled as a helix into a solenoid coil by William Sturgeon in 1823 and was improved by Joseph Henry in 1829 [see http://www.myetymology.com/encyclopedia/History_of_the_electricity.html; J. M. D. Coey, Magnetism and Magnetic Materials (Cambridge University Press, New York, 2010); and F. Winterberg, Plasma Phys. 8, 541553 (1996)]. A magnetic control method of C-shaped carrying-current wire is proposed, and thereby a new opening electromagnetic transducer evidently differing from the traditional tubular solenoid is created, capable of directly encircling and centering the acted objects in it, bringing about convenient and innovative electromagnetic energy conversion for electromagnetic heating, electromagnetic excitation, physical information capture, and electro-mechanical motion used in science research, industry, and even biomedical activities.

Sun, Yanhua; Kang, Yihua

2013-12-01

47

Electromagnetism from counting.  

National Technical Information Service (NTIS)

The fact that experimental accuracy is finite makes the measurement of particle positions and velocities non-local and often non- commutative even in a scale invariant theory. Applied to electromagnetic and gravitational phenomena, we argue that this lead...

H. P. Noyes

1992-01-01

48

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

49

ADAPTING GID FOR ELECTROMAGNETICS  

Microsoft Academic Search

The objective of this paper is to show and share the experiences on the use of GiD as a pre- and post- processor for some of the electromagnetic FEM codes developed in the Research Group that the authors belong to. GiD has advantageous features but important limitations for electromagnetic problems, mainly due to the unavailability of non-standard (H(curl) and H(div)

Diego Sánchez-Repila; Luis E. García-Castillo

50

Inhomogeneous electromagnetic gravitational collapse  

SciTech Connect

The collapse of an inhomogeneous dust cloud in the presence of an electromagnetic field is investigated in detail. The possibility of a naked singularity arising is studied using some known solutions for a spherical charged inhomogeneous dust cloud. It is found that locally naked singularities may develop when the arbitrary functions in the solution are chosen in a special way, but that a global naked singularity will not form. Also the role of the electromagnetic pressure is discussed.

Stein-Schabes, J.A.

1985-04-15

51

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

52

Electromagnetic attachment mechanism  

NASA Technical Reports Server (NTRS)

An electromagnetic attachment mechanism is disclosed for use as an end effector of a remote manipulator system. A pair of electromagnets, each with a U-shaped magnetic core with a pull-in coil and two holding coils, are mounted by a spring suspension system on a base plate of the mechanism housing with end pole pieces adapted to move through openings in the base plate when the attractive force of the electromagnets is exerted on a strike plate of a grapple fixture affixed to a target object. The pole pieces are spaced by an air gap from the strike plate when the mechanism first contacts the grapple fixture. An individual control circuit and power source is provided for the pull-in coil and one holding coil of each electromagnet. A back-up control circuit connected to the two power sources and a third power source is provided for the remaining holding coils. When energized, the pull-in coils overcome the suspension system and air gap and are automatically de-energized when the pole pieces move to grapple and impose a preload force across the grapple interface. A battery backup is a redundant power source for each electromagnet in each individual control circuit and is automatically connected upon failure of the primary source. A centerline mounted camera and video monitor are used in cooperation with a target pattern on the reflective surface of the strike plate to effect targeting and alignment.

Monford, Leo G., Jr. (inventor)

1992-01-01

53

Electromagnetic particle simulation codes  

NASA Technical Reports Server (NTRS)

Electromagnetic particle simulations solve the full set of Maxwell's equations. They thus include the effects of self-consistent electric and magnetic fields, magnetic induction, and electromagnetic radiation. The algorithms for an electromagnetic code which works directly with the electric and magnetic fields are described. The fields and current are separated into transverse and longitudinal components. The transverse E and B fields are integrated in time using a leapfrog scheme applied to the Fourier components. The particle pushing is performed via the relativistic Lorentz force equation for the particle momentum. As an example, simulation results are presented for the electron cyclotron maser instability which illustrate the importance of relativistic effects on the wave-particle resonance condition and on wave dispersion.

Pritchett, P. L.

1985-01-01

54

Aircraft electromagnetic compatibility  

NASA Technical Reports Server (NTRS)

Illustrated are aircraft architecture, electromagnetic interference environments, electromagnetic compatibility protection techniques, program specifications, tasks, and verification and validation procedures. The environment of 400 Hz power, electrical transients, and radio frequency fields are portrayed and related to thresholds of avionics electronics. Five layers of protection for avionics are defined. Recognition is given to some present day electromagnetic compatibility weaknesses and issues which serve to reemphasize the importance of EMC verification of equipment and parts, and their ultimate EMC validation on the aircraft. Proven standards of grounding, bonding, shielding, wiring, and packaging are laid out to help provide a foundation for a comprehensive approach to successful future aircraft design and an understanding of cost effective EMC in an aircraft setting.

Clarke, Clifton A.; Larsen, William E.

1987-01-01

55

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

2012-06-19

56

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  

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.

C. D. Ponds

1985-01-01

57

Improved Electromagnetic Brake  

NASA Technical Reports Server (NTRS)

A proposed design for an electromagnetic brake would increase the reliability while reducing the number of parts and the weight, relative to a prior commercially available electromagnetic brake. The reductions of weight and the number of parts could also lead to a reduction of cost. A description of the commercial brake is prerequisite to a description of the proposed electromagnetic brake. The commercial brake (see upper part of figure) includes (1) a permanent magnet and an electromagnet coil on a stator and (2) a rotor that includes a steel contact plate mounted, with tension spring loading, on an aluminum hub. The stator is mounted securely on a stationary object, which would ordinarily be the housing of a gear drive or a motor. The rotor is mounted on the shaft of the gear drive or motor. The commercial brake nominally operates in a fail-safe (in the sense of normally braking) mode: In the absence of current in the electromagnet coil, the permanent magnet pulls the contact plate, against the spring tension, into contact with the stator. To release the brake, one excites the electromagnet with a current of the magnitude and polarity chosen to cancel the magnetic flux of the permanent magnet, thereby enabling the spring tension to pull the contact plate out of contact with the stator. The fail-safe operation of the commercial brake depends on careful mounting of the rotor in relation to the stator. The rotor/stator gap must be set with a tolerance between 10 and 15 mils (between about 0.25 and about 0.38 mm). If the gap or the contact pad is thicker than the maximum allowable value, then the permanent magnetic field will not be strong enough to pull the steel plate across the gap. (For this reason, any contact pad between the contact plate and the stator must also be correspondingly thin.) If the gap exceeds the maximum allowable value because of shaft end play, it becomes impossible to set the brake by turning off the electromagnet current. Although it may still be possible to set the brake by applying an electromagnet current to aid the permanent magnetic field instead of canceling it, this action can mask an out-of-tolerance condition in the brake and it does not restore the fail-safe function of setting the brake when current is lost.

Martin, Toby B.

2004-01-01

58

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

59

Canceling Electromagnetic Interference During Tests  

NASA Technical Reports Server (NTRS)

Old technique solves modern problem. Simple amplitude-and-phase-cancellation technique removes strong electromagnetic interference from received test signal, enabling recovery of relatively weak signal from device under test. Useful in outdoor tests of devices for electromagnetic compatibility.

Robinson, Paul A., Jr.; Edmonds, Larry D.

1988-01-01

60

New Perspective on Classical Electromagnetism.  

National Technical Information Service (NTIS)

The fallacies associated with the gauge concept in electromagnetism are illustrated. A clearer and more valid formulation of the basics of classical electromagnetism is provided by recognizing a previously overlooked law of induction as well as the physic...

M. Johnson P. Cote

2013-01-01

61

Electromagnetic simulation environment  

Microsoft Academic Search

We present a general purpose simulator that includes electromagnetic scattering tools for buried targets and standard signal processing functionality. Additional modules for genetic or gradient optimization, parallel processing, and multi-aspect target detection via Hidden Markov Models are also available. The entire library is completely scriptable for customization and web enabled for publishing results on the internet. It is also extensible

Eric Jones; Balaji Krishnapuram; John Pormann; John A. Board; Lawrence Carin

2001-01-01

62

Electro-Magnetic Actuator.  

National Technical Information Service (NTIS)

The electro-magnetic wave generator is particularly adapted for creating a rotating wave in the flexible ring gear of a harmonic drive device. One application of the harmonic drive as a speed reducer is in propelling small, deep diving research submarines...

C. F. Janes

1965-01-01

63

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

64

Equivalence principles and electromagnetism  

NASA Technical Reports Server (NTRS)

The implications of the weak equivalence principles are investigated in detail for electromagnetic systems in a general framework. In particular, it is shown that the universality of free-fall trajectories (Galileo weak equivalence principle) does not imply the validity of the Einstein equivalence principle. However, the Galileo principle plus the universality of free-fall rotation states does imply the Einstein principle.

Ni, W.-T.

1977-01-01

65

Electromagnetic brain mapping  

Microsoft Academic Search

There has been tremendous advances in our ability to produce images of human brain function. Applications of functional brain imaging extend from improving our understanding of the basic mechanisms of cognitive processes to better characterization of pathologies that impair normal function. Magnetoencephalography (MEG) and electroencephalography (EEG) (MEG\\/EEG) localize neural electrical activity using noninvasive measurements of external electromagnetic signals. Among the

S. Baillet; J. C. Mosher; R. M. Leahy

2001-01-01

66

Nuclear Electromagnetic Pulse Review  

Microsoft Academic Search

Electromagnetic Pulse (EMP) from nuclear detonations have been observed for well over half a century. Beginning in the mid-to-late 1950s, the physics and modeling of EMP has been researched and will continue into the foreseeable future. The EMP environment propagates hundreds of miles from its origins and causes interference for all types of electronic instrumentation. This includes military, municipal and

Michael Dinallo

2011-01-01

67

Adaptive electromagnetic shunt damping  

Microsoft Academic Search

This paper presents a new type of passive vibration control: adaptive electromagnetic shunt damping. We propose a single-mode resonant shunt controller that adapts to environmental conditions using two different adaptation strategies. The first technique is based on minimizing the root mean square (RMS) vibration, while the second minimizes the phase difference between two measurable signals. An experimental comparison shows that

Dominik Niederberger; Sam Behrens; Andrew J. Fleming; S. O. R. Moheimani; Manfred Morari

2006-01-01

68

Focusing of electromagnetic waves.  

National Technical Information Service (NTIS)

The focusing of electromagnetic waves inside a slab has been examined together with two special cases in which the slab is reduced to a single interface or a single medium. To that end the exact solutions for the fields inside a layered medium have been u...

V. Dhayalan

1996-01-01

69

Simple Superconducting "Permanent" Electromagnet  

NASA Technical Reports Server (NTRS)

Proposed short tube of high-temperature-superconducting material like YBa2Cu3O7 acts as strong electromagnet that flows as long as magnetic field remains below critical value and temperature of cylinder maintained sufficiently below superconducting-transition temperature. Design exploits maximally anisotropy of high-temperature-superconducting material.

Israelson, Ulf E.; Strayer, Donald M.

1992-01-01

70

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

71

What are Electromagnetic Metamaterials?  

NSDL National Science Digital Library

Metamaterials are artificial structures that display properties beyond those available in naturally occuring materials. Materials interact with light and other electromagnetic fields. Because of this, materials can be used to control light in various ways, forming the basis for optical devices. This website from Duke University gives more details and graphs.

2011-08-29

72

SOLAR NANTENNA ELECTROMAGNETIC COLLECTORS  

Microsoft Academic Search

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

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

2008-01-01

73

Computational Electronics and Electromagnetics  

SciTech Connect

The Computational Electronics and Electromagnetics thrust area is a focal point for computer modeling activities in electronics and electromagnetics in the Electronics Engineering Department of Lawrence Livermore National Laboratory (LLNL). Traditionally, they have focused their efforts in technical areas of importance to existing and developing LLNL programs, and this continues to form the basis for much of their research. A relatively new and increasingly important emphasis for the thrust area is the formation of partnerships with industry and the application of their simulation technology and expertise to the solution of problems faced by industry. The activities of the thrust area fall into three broad categories: (1) the development of theoretical and computational models of electronic and electromagnetic phenomena, (2) the development of useful and robust software tools based on these models, and (3) the application of these tools to programmatic and industrial problems. In FY-92, they worked on projects in all of the areas outlined above. The object of their work on numerical electromagnetic algorithms continues to be the improvement of time-domain algorithms for electromagnetic simulation on unstructured conforming grids. The thrust area is also investigating various technologies for conforming-grid mesh generation to simplify the application of their advanced field solvers to design problems involving complicated geometries. They are developing a major code suite based on the three-dimensional (3-D), conforming-grid, time-domain code DSI3D. They continue to maintain and distribute the 3-D, finite-difference time-domain (FDTD) code TSAR, which is installed at several dozen university, government, and industry sites.

DeFord, J.F.

1993-03-01

74

Electromagnetic effects in crustal fracturing  

NASA Astrophysics Data System (ADS)

The major results from field observation of electromagnetic precursors of seismic events are presented. These phenomena, including disturbances in the atmospheric electric potential, pulsed electromagnetic radiation, electrotelluric fields and luminous effects, characteristically appear on the order of the hours to days before earthquakes, with earthquakes occurring during a decrease in the phenomena. The phenomena occur over a broad frequency range. All anomalies except for electromagnetic radiation have been observed at the epicenters of earthquakes. Foreshocks have not been recorded during these anomalies. No burst of electromagnetic, atmospheric electric or electrotelluric fields has been observed at the moment of earthquakes. Electromagnetic radiation in the radio frequency band is considered most promising for earthquake prediction purposes. The specific characteristics of electromagnetic radiation caused by seismic phenomena must be determined in order to distinguish this radiation from other electromagnetic radiation.

Gokhberg, M. B.; Gufeld, I. L.; Gershenzon, N. I.; Pilipenko, V. A.

1985-08-01

75

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

76

Magnetism and Electromagnetism  

NSDL National Science Digital Library

All About Circuits is a website that âÂÂprovides a series of online textbooks covering electricity and electronics.â Written by Tony R. Kuphaldt, the textbooks available here are wonderful resources for students, teachers, and anyone who is interested in learning more about electronics. This specific section, Magnetism and Electromagnetism, is the fourteenth chapter in Volume I â Direct Current. A few of the topics covered in this chapter include: Permanent magnets; Electromagnetic induction; and Mutual inductance. Diagrams and detailed descriptions of concepts are included throughout the chapter to provide users with a comprehensive lesson. Visitors to the site are also encouraged to discuss concepts and topics using the All About Circuits discussion forums (registration with the site is required to post materials).

Kuphaldt, Tony R.

2008-07-07

77

Electromagnetic wave energy converter  

NASA Technical Reports Server (NTRS)

Electromagnetic wave energy is converted into electric power with an array of mutually insulated electromagnetic wave absorber elements each responsive to an electric field component of the wave as it impinges thereon. Each element includes a portion tapered in the direction of wave propagation to provide a relatively wideband response spectrum. Each element includes an output for deriving a voltage replica of the electric field variations intercepted by it. Adjacent elements are positioned relative to each other so that an electric field subsists between adjacent elements in response to the impinging wave. The electric field results in a voltage difference between adjacent elements that is fed to a rectifier to derive dc output power.

Bailey, R. L. (inventor)

1973-01-01

78

Ordinary electromagnetic mode instability  

NASA Technical Reports Server (NTRS)

The instability of the ordinary electromagnetic mode propagating perpendicular to an external magnetic field is studied for a single-species plasma with ring velocity distribution. The marginal instability boundaries for both the purely growing mode and the propagating growing modes are calculated from the instability criteria. The dispersion characteristics for various sets of plasma parameters are also given. The typical growth rates are of the order of the cyclotron frequency.

Cheng, C. Z.

1974-01-01

79

Electromagnetic Hammer for Metalworking  

NASA Technical Reports Server (NTRS)

High eddy currents apply pressure for cold-forming. Coil housing constructed for mechanical strength to hold coil against magnetic force, to maintain electrical contact with coil ends, and to maintain insulation between coil turns. Drilled holes placed to facilitate release of bubbles during potting. In contrast with mechanical hammers, electromagnetic hammer requires no dynamic material contact with workpiece; consequently, produces almost no change in metal grain structure.

Anderson, S. A.; Brunet, F.; Dowd, A.; Durham, R.; Ezell, J.; Gorr, G.; Hartley, D.; Jackson, F.; Marchand, J.; Macfarlane, W.; Nameth, P.; Okelly, K.; Phillips, H.; Rollo, J.; Rupert, E.; Sykes, H.; Vitrano, E.; Woods, M.

1986-01-01

80

Electromagnetic Interference Reduction Filters  

Microsoft Academic Search

This paper presents the theory and application of lumped-image parameter reactive filter networks, absorptive-type filter networks, and combined absorptive-reactive filter networks as conducted electromagnetic interference reduction circuits. A comparison of the passband characteristics by specific examples is given for filter configurations of the pi, T, absorptive, and absorptive-reactive type under implementation conditions of a fixed source impedance and a varying

Henry Hoffart

1968-01-01

81

The KLOE electromagnetic calorimeter  

Microsoft Academic Search

The KLOE calorimeter is a fine lead-scintillating fiber sampling calorimeter. We describe in the following the calibration procedures and the calorimeter performances obtained after 3 years of data taking. We get an energy resolution for electromagnetic showers of 5.4%\\/E(GeV) and a time resolution of 56 ps\\/E(GeV). We also present a measurement of efficiency for low-energy photons.

M. Adinolfi; F. Ambrosino; A. Antonelli; M. Antonelli; F. Anulli; G. Barbiellini; G. Bencivenni; S. Bertolucci; C. Bini; C. Bloise; V. Bocci; F. Bossi; P. Branchini; G. Cabibbo; R. Caloi; P. Campana; M. Casarsa; G. Cataldi; F. Ceradini; F. Cervelli; P. Ciambrone; E. De Lucia; P. De Simone; G. De Zorzi; S. Dell'Agnello; A. Denig; A. di Domenico; C. di Donato; S. Di Falco; A. Doria; O. Erriquez; A. Farilla; A. Ferrari; M. L. Ferrer; G. Finocchiaro; C. Forti; A. Franceschi; P. Franzini; M. L. Gao; C. Gatti; P. Gauzzi; A. Giannasi; S. Giovannella; E. Graziani; H. G. Han; S. W. Han; X. Huang; M. Incagli; L. Ingrosso; L. Keeble; W. Kim; C. Kuo; G. Lanfranchi; J. Lee-Franzini; T. Lomtadze; C. S. Mao; M. Martemianov; W. Mei; R. Messi; S. Miscetti; S. Moccia; M. Moulson; S. Müller; F. Murtas; L. Pacciani; M. Palomba; M. Palutan; E. Pasqualucci; L. Passalacqua; A. Passeri; D. Picca; G. Pirozzi; L. Pontecorvo; M. Primavera; P. Santangelo; E. Santovetti; G. Saracino; R. D. Schamberger; B. Sciascia; F. Scuri; I. Sfiligoi; P. Silano; T. Spadaro; E. Spiriti; L. Tortora; P. Valente; B. Valeriani; G. Venanzoni; A. Ventura; S. Wölfle; Y. Wu; Y. G. Xie; P. F. Zema; C. D. Zhang; J. Q. Zhang; P. P. Zhao

2002-01-01

82

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.

Fanning, Alan W. (San Jose, CA); Gonzales, Aaron A. (San Jose, CA); Patel, Mahadeo R. (San Jose, CA); Olich, Eugene E. (Aptos, CA)

1994-01-01

83

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.

Fanning, Alan W. (San Jose, CA); Gonzales, Aaron A. (San Jose, CA); Patel, Mahadeo R. (San Jose, CA); Olich, Eugene E. (Aptos, CA)

1996-01-01

84

Isotropic metamaterial electromagnetic lens  

Microsoft Academic Search

Several authors have recently exhibited the focusing activity in the domain of so-called electromagnetic lenses. These lenses are parallel-plate layers of metamaterials whose properties can be described in terms of negative index of refraction. Known works on this subject refer to 2D structures. This work is our first attempt to show the focusing effect by a parallel-plate layer of a

E. Verney; B. Sauviac; C. R. Simovski

2004-01-01

85

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

86

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

87

Nuclear Electromagnetic Pulse Review  

NASA Astrophysics Data System (ADS)

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

Dinallo, Michael

2011-04-01

88

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

89

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

90

Electromagnetic field and cosmic censorship  

NASA Astrophysics Data System (ADS)

We construct a gedanken experiment in which an extremal Kerr black hole interacts with a test electromagnetic field. Using Teukolsky's solutions for electromagnetic perturbations in Kerr spacetime, and the conservation laws imposed by the energy momentum tensor of the electromagnetic field and the Killing vectors of the spacetime, we prove that this interaction cannot convert the black hole into a naked singularity, thus cosmic censorship conjecture is not violated in this case.

Düzta?, Koray

2014-04-01

91

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

92

Electromagnetic Theory 3 Volume Set  

NASA Astrophysics Data System (ADS)

Volume 1: Preface; 1. Introduction; 2. Outline of the electromagnetic connections; 3. The elements of vectorial algebra and analysis; 4. Theory of plane electromagnetic waves; Appendix. Volume 2: Preface; 5. Mathematics and the age of the earth; 6. Pure diffusion of electric displacement; 7. Electromagnetic waves and generalised differentiation; 8. Generalised differentiation and divergent series; Appendix. Volume 3: 9. Waves from moving sources; 10. Waves in the ether.

Heaviside, Oliver

2011-09-01

93

Does “electromagnetic pollution” cause illness?  

Microsoft Academic Search

Summary More and more self-declared electromagnetic hypersensitive patients are entering physicians’ practices seeking help. To assess the prevalence of cases and the opinion of Austrian physicians regarding the potential health-relevance of environmental electromagnetic fields (“electromagnetic pollution”), a statistical investigation among general practitioners was undertaken, with surprising results. Only one-third report on never having been asked about the health impact of

Norbert Leitgeb; Jörg Schröttner; Michael Böhm

2005-01-01

94

Electromagnetic pump stator coil  

DOEpatents

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.

Fanning, Alan W. (San Jose, CA); Dahl, Leslie R. (Livermore, CA)

1996-01-01

95

Electromagnetic pump stator coil  

DOEpatents

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

96

Electromagnetic strong plasma turbulence  

NASA Astrophysics Data System (ADS)

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.

2007-02-01

97

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

98

Electro-magnetic compatibility  

NASA Astrophysics Data System (ADS)

The historical background to the growth in problems of electromagnetic compatibility (EMC) in UK Military aircraft is reviewed and the present approach for minimizing these problems during development is discussed. The importance of using representative aircraft for final EMC assessments is stressed, and the methods of approach in planning and executing such tests are also outlined. The present equipment qualification procedures are based on assumptions regarding the electromagnetic fields present within the airframe, and the nature of the coupling mechanisms. These cannot be measured with any certainty in representative aircraft. Thus EMC assessments rely on practical tests. Avionics systems critical to flight safety, and systems vital to mission effectiveness require test methods that provide a measure of the safety and performance margins available to account for variations that occur in production and service use. Some proven methods are available, notably for detonator circuits, but in most other areas further work is required. Encouraging process has been made in the use of current probes for the measurement of interfering signals on critical signal lines, in conjunction with complementary test house procedures, as a means for obtaining the safety margins required in flight and engine control systems. Performance margins for mission systems using digital techniques are difficult to determine, and there is a need for improved test techniques. The present EMC qualification tests for equipment in the laboratory do not guarantee freedom from interference when installed, and the results are limited in value for correlating with aircraft tests.

Maidment, H.

1980-05-01

99

Electromagnetic propulsion for spacecraft  

NASA Technical Reports Server (NTRS)

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.

1993-01-01

100

Metamaterials beyond electromagnetism  

NASA Astrophysics Data System (ADS)

Metamaterials are rationally designed man-made structures composed of functional building blocks that are densely packed into an effective (crystalline) material. While metamaterials are mostly associated with negative refractive indices and invisibility cloaking in electromagnetism or optics, the deceptively simple metamaterial concept also applies to rather different areas such as thermodynamics, classical mechanics (including elastostatics, acoustics, fluid dynamics and elastodynamics), and, in principle, also to quantum mechanics. We review the basic concepts, analogies and differences to electromagnetism, and give an overview on the current state of the art regarding theory and experiment—all from the viewpoint of an experimentalist. This review includes homogeneous metamaterials as well as intentionally inhomogeneous metamaterial architectures designed by coordinate-transformation-based approaches analogous to transformation optics. Examples are laminates, transient thermal cloaks, thermal concentrators and inverters, ‘space-coiling’ metamaterials, anisotropic acoustic metamaterials, acoustic free-space and carpet cloaks, cloaks for gravitational surface waves, auxetic mechanical metamaterials, pentamode metamaterials (‘meta-liquids’), mechanical metamaterials with negative dynamic mass density, negative dynamic bulk modulus, or negative phase velocity, seismic metamaterials, cloaks for flexural waves in thin plates and three-dimensional elastostatic cloaks.

Kadic, Muamer; Bückmann, Tiemo; Schittny, Robert; Wegener, Martin

2013-12-01

101

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

102

Electromagnetic Field Penetration Studies  

NASA Technical Reports Server (NTRS)

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

Deshpande, M.D.

2000-01-01

103

New Scheme for Electromagnetic Simulations  

Microsoft Academic Search

A new explicit time stepping scheme for electromagnetic simulations is described, the neo-finite-difference method. This numerical method which describes the time derivative as an arc instead of a straight line is more accurate. Thus, larger time steps can be used than with the standard leapfrog method. We start by Fourier analyzing the electromagnetic field in space. The Fourier amplitudes obey

K. R. Chen; J. M. Dawson

1995-01-01

104

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

105

Particle swarm optimization in electromagnetics  

Microsoft Academic Search

The particle swarm optimization (PSO), new to the electromagnetics community, is a robust stochastic evolutionary computation technique based on the movement and intelligence of swarms. This paper introduces a conceptual overview and detailed explanation of the PSO algorithm, as well as how it can be used for electromagnetic optimizations. This paper also presents several results illustrating the swarm behavior in

Jacob Robinson; Yahya Rahmat-Samii

2004-01-01

106

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

107

Gravitational scattering of electromagnetic radiation  

NASA Technical Reports Server (NTRS)

The scattering of electromagnetic radiation by linearized gravitational fields is studied to second order in a perturbation expansion. The incoming electromagnetic radiation can be of arbitrary multipole structure, and the gravitational fields are also taken to be advanced fields of arbitrary multipole structure. All electromagnetic multipole radiation is found to be scattered by gravitational monopole and time-varying dipole fields. No case has been found, however, in which any electromagnetic multipole radiation is scattered by gravitational fields of quadrupole or higher-order multipole structure. This lack of scattering is established for infinite classes of special cases, and is conjectured to hold in general. The results of the scattering analysis are applied to the case of electromagnetic radiation scattered by a moving mass. It is shown how the mass and velocity may be determined by a knowledge of the incident and scattered radiation.

Brooker, J. T.; Janis, A. I.

1980-01-01

108

The Electromagnetic Spectrum  

NSDL National Science Digital Library

In this lesson, students are introduced to the electromagnetic spectrum. They observe a demonstration of the visible light spectrum created by a flashlight and a prism, complete an activity sheet where they identify the wavelength that is involved in technologies used in their communities, and learn about satellite sensors that remotely sense data. Student worksheets, a data sheet, answer keys, and Web links are included. This is Lesson 3 in Understanding Light, part of IMAGERS, Interactive Media Adventures for Grade School Education using Remote Sensing. The website provides hands-on activities in the classroom supporting the science content in two interactive media books, The Adventures of Echo the Bat and Amelia the Pigeon.

109

Novel electromagnetic accelerometer  

NASA Astrophysics Data System (ADS)

A novel micro-accelerometer based on electromagnetic field induction has been fabricated from Si (100) wafers using silicon micro machining techniques. For this design, measurements of acceleration ranging from 0-50 g have been experimentally demonstrated. The physical structure and a brief description of the fabrication process is given. The actual size of the device is 4.2 x 4.2 mm, its amplified output voltage varies linearly from 0-9 V with the rate of 0.175 V/g and the power consumption is less than 2.5 mW. Due to the simple structure a batch processing with on chip signal conditioning circuitry is possible. The required electronic circuitry compared to the capacitive accelerometers is much simpler.

Abbaspour-Sani, Ebrahim; Huang, Ruey-Shing; Kwok, Chee Yee

1994-08-01

110

Electromagnetic propulsion for spacecraft  

NASA Technical Reports Server (NTRS)

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.

1993-01-01

111

Superconducting electromagnetic thruster  

NASA Astrophysics Data System (ADS)

An electromagnetic thruster for marine vehicles using a jet of water driven by the interaction of a mutually perpendicular intensified magnetic field and an intensified electric field is disclosed. The intensified magnetic field is produced by superconducting coils cooled by a coolant such as liquid helium. An intensified electric field is produced by passing high amperage current across the seawater jet. These interacting fields produce a Lorentz force perpendicular to mutually perpendicular electric and magnetic field vectors which is used to drive the seawater jet. In some embodiments, the force may also be used to draw water into the jet from the boundary layer flow around the vehicle thereby reducing boundary layer turbulence and associated radiated noise.

Meng, James C.

1994-08-01

112

Superconducting electromagnetic thruster  

SciTech Connect

An electromagnetic thruster for marine vehicles using a jet of water driven by the interaction of a mutually perpendicular intensified magnetic field and an intensified electric field is disclosed. The intensified magnetic field is produced by superconducting coils cooled by a coolant such as liquid helium. An intensified electric field is produced by passing high amperage current across the seawater jet. These interacting fields produce a Lorentz force perpendicular to mutually perpendicular electric and magnetic field vectors which is used to drive the seawater jet. In some embodiments, the force may also be used to draw water into the jet from the boundary layer flow around the vehicle thereby reducing boundary layer turbulence and associated radiated noise.

Meng, J.

1993-02-11

113

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

114

Electromagnetically Clean Solar Arrays  

NASA Technical Reports Server (NTRS)

The term 'electromagnetically clean solar array' ('EMCSA') refers to a panel that contains a planar array of solar photovoltaic cells and that, in comparison with a functionally equivalent solar-array panel of a type heretofore used on spacecraft, (1) exhibits less electromagnetic interferences to and from other nearby electrical and electronic equipment and (2) can be manufactured at lower cost. The reduction of electromagnetic interferences is effected through a combination of (1) electrically conductive, electrically grounded shielding and (2) reduction of areas of current loops (in order to reduce magnetic moments). The reduction of cost is effected by designing the array to be fabricated as a more nearly unitary structure, using fewer components and fewer process steps. Although EMCSAs were conceived primarily for use on spacecraft they are also potentially advantageous for terrestrial applications in which there are requirements to limit electromagnetic interference. In a conventional solar panel of the type meant to be supplanted by an EMCSA panel, the wiring is normally located on the back side, separated from the cells, thereby giving rise to current loops having significant areas and, consequently, significant magnetic moments. Current-loop geometries are chosen in an effort to balance opposing magnetic moments to limit far-0field magnetic interactions, but the relatively large distances separating current loops makes full cancellation of magnetic fields problematic. The panel is assembled from bare photovoltaic cells by means of multiple sensitive process steps that contribute significantly to cost, especially if electomagnetic cleanliness is desired. The steps include applying a cover glass and electrical-interconnect-cell (CIC) sub-assemble, connecting the CIC subassemblies into strings of series-connected cells, laying down and adhesively bonding the strings onto a panel structure that has been made in a separate multi-step process, and mounting the wiring on the back of the panel. Each step increases the potential for occurrence of latent defects, loss of process control, and attrition of components. An EMCSA panel includes an integral cover made from a transparent material. The silicone cover supplants the individual cover glasses on the cells and serves as an additional unitary structural support that offers the advantage, relative to glass, of the robust, forgiving nature of the silcone material. The cover contains pockets that hold the solar cells in place during the lamination process. The cover is coated with indium tin oxide to make its surface electrically conductive, so that it serves as a contiguous, electrically grounded shield over the entire panel surface. The cells are mounted in proximity to metallic printed wiring. The painted-wiring layer comprises metal-film traces on a sheet of Kapton (or equivalent) polyimide. The traces include contact pads on one side of the sheet for interconnecting the cells. Return leads are on the opposite side of the sheet, positioned to form the return currents substantially as mirror images of, and in proximity to, the cell sheet currents, thereby minimizing magnetic moments. The printed-wiring arrangement mimics the back-wiring arrangement of conventional solar arrays, but the current-loop areas and the resulting magnetic moments are much smaller because the return-current paths are much closer to the solar-cell sheet currents. The contact pads are prepared with solder fo electrical and mechanical bonding to the cells. The pocketed cover/shield, the solar cells, the printed-wiring layer, an electrical bonding agent, a mechanical-bonding agent, a composite structural front-side face sheet, an aluminum honeycomb core, and a composite back-side face sheet are all assembled, then contact pads are soldered to the cells and the agents are cured in a single lamination process.

Stem, Theodore G.; Kenniston, Anthony E.

2008-01-01

115

Electromagnetic inverse scattering  

NASA Technical Reports Server (NTRS)

A three-dimensional electromagnetic inverse scattering identity, based on the physical optics approximation, is developed for the monostatic scattered far field cross section of perfect conductors. Uniqueness of this inverse identity is proven. This identity requires complete scattering information for all frequencies and aspect angles. A nonsingular integral equation is developed for the arbitrary case of incomplete frequence and/or aspect angle scattering information. A general closed-form solution to this integral equation is developed, which yields the shape of the scatterer from such incomplete information. A specific practical radar solution is presented. The resolution of this solution is developed, yielding short-pulse target resolution radar system parameter equations. The special cases of two- and one-dimensional inverse scattering and the special case of a priori knowledge of scatterer symmetry are treated in some detail. The merits of this solution over the conventional radar imaging technique are discussed.

Bojarski, N. N.

1972-01-01

116

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

117

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

118

Electromagnetic Field Effects in Explosives  

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

119

From the electromagnetic pulse to high-power electromagnetics  

Microsoft Academic Search

Since the 1960s significant effort has gone into developing requisite technology for the nuclear electromagnetic pulse (EMP). In the late 1970s several important summary documents were published. The author updates this information to the present. It is noted that EMP has affected a set of related areas which can be collectively referred to as high-power electromagnetics (HPE). This includes direct-strike

CARL E. BAUM

1992-01-01

120

Electromagnetic Modeling of Display Module Interconnect  

Microsoft Academic Search

This paper deals with the use of the computational electromagnetic modeling into the electromagnetic design (EMD) of an electronic system as apart of design process. In this paper an electric and electromagnetic computational verification flow is suggested. As an application electromagnetic modeling of interconnect of display module is investigated using suggested the EMD computational verification flow

A. N. Arslan; V. Hurskainen; I. Pankinaho; I. Kelander; A. Rautio

2006-01-01

121

Accurate computational method for solving electromagnetic wave  

Microsoft Academic Search

This paper studied in solving monochromatic electromagnetic wave. Under such circumstances of axial symmetric and passive electromagnetic wave that is finite and differentiable on the symmetric axis, a new approximation theory and evolutionary computing method are provided by using Maxwell equations. Out-of-axis electromagnetic wave can be expressed as series with the method. This series contains electromagnetic wave on the symmetric

Li Zijun; Fang Benying

2009-01-01

122

Measurement of electromagnetic energy flow  

NASA Astrophysics Data System (ADS)

The measurement of electromagnetic energy flow is an integral part of solving radiation-budget and optical-characterization problems. It is therefore very important to understand clearly what specific measurement is afforded by an optical instrument and how to model this measurement theoretically. We will not discuss technical and technological issues related to the development of sensitive and efficient detectors of light. Instead, the discussion will focus on the precise definitions of general measurement principles and their specific practical implications in the framework of electromagnetic scattering by particles and particle groups. We will discuss in succession measurements with direction-insensitive detectors, monodirectional well-collimated, and panoramic well-collimated radiometers. Special attention will be paid to the electromagnetic response of a well-collimated radiometer to polychromatic light. We will see, in particular, that although the main characteristic of electromagnetic energy flow is the Poynting vector, the actual measurement of this quantity is possible only in very special cases.

Mishchenko, M. I.

2012-12-01

123

Vertical Electromagnetic Pulse (VEMP) Testing.  

National Technical Information Service (NTIS)

This TOP provides methods for planning, providing instrumentation, and execution of testing of Army/DOD Materiel to determine the effects of Vertical Component High Altitude Electromagnetic Pulse (VHEMP) Environment on the safety and/or reliability of the...

2009-01-01

124

Electromagnetic Interference In New Aircraft  

NASA Technical Reports Server (NTRS)

Report reviews plans to develop tests and standards to ensure that digital avionics systems in new civil aircraft immune to electromagnetic interference (EMI). Updated standards reflect more severe environment and vulnerabilities of modern avionics.

Larsen, William E.

1991-01-01

125

Electromagnetic Showers at High Energy  

ERIC Educational Resources Information Center

Some of the properties of electromagnetic showers observed in an experimental study are illustrated. Experimental data and results from quantum electrodynamics are discussed. Data and theory are compared using computer simulation. (BB)

Loos, J. S.; Dawson, S. L.

1978-01-01

126

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

127

Tracking Electromagnetic Energy With SQUIDs.  

National Technical Information Service (NTIS)

A superconducting quantum interference device (SQUID) is a gadget used to measure extremely weak signals, specifically magnetic flux. It can detect subtle changes in energy, up to 100 billion times weaker than the electromagnetic energy required to move a...

2005-01-01

128

Conical electromagnetic radiation flux concentrator  

NASA Technical Reports Server (NTRS)

Concentrator provides method of concentrating a beam of electromagnetic radiation into a smaller beam, presenting a higher flux density. Smaller beam may be made larger by sending radiation through the device in the reverse direction.

Miller, E. R.

1972-01-01

129

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

130

[Electromagnetic field intolerance: a nonexistent disease?].  

PubMed

Idiopathic Environmental Intolerance Attributed to Electromagnetic Fields is a relatively new phenomenon, which is not fully understood. Extensive research has been carried out to exclude or confirm out that symptoms reported by sufferers are caused by electromagnetic field. This article describes outcomes of recent experiments and meta-analyses. The article may answer to the question if electromagnetic field does really cause reported symptoms, furthermore, it provides hypothetical explanation of this phenomenon. Keywords: electromagnetic hypersensitivity - electromagnetic field - nonspecific symptoms - nocebo effect. PMID:24506686

Safá?ová, Sárka

2014-01-01

131

Pulsed electromagnetic gas acceleration  

NASA Technical Reports Server (NTRS)

Detailed measurements of the axial velocity profile and electromagnetic structure of a high power, quasi-steady MPD discharge are used to formulate a gasdynamic model of the acceleration process. Conceptually dividing the accelerated plasma into an inner flow and an outer flow, it is found that more than two-thirds of the total power in the plasma is deposited in the inner flow, accelerating it to an exhaust velocity of 12.5 km/sec. The outer flow, which is accelerated to a velocity of only 6.2 km/sec, appears to provide a current conduction path between the inner flow and the anode. Related cathode studies have shown that the critical current for the onset of terminal voltage fluctuations, which was recently shown to be a function of the cathode area, appears to reach an asymptote for cathodes of very large surface area. Detailed floating potential measurements show that the fluctuations are confined to the vicinity of the cathode and hence reflect a cathode emission process rather than a fundamental limit on MPD performance.

Jahn, R. G.; Vonjaskowsky, W. F.; Clark, K. E.

1974-01-01

132

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

133

Modern electromagnetic scattering  

NASA Astrophysics Data System (ADS)

We develop a numerically stable algorithm for electromagnetic wave propagation through planar stratified media. This algorithm is implemented in a modern programming language and is suitable for the study of such applications as Anderson localization and perfect lensing. Our algorithm remains numerically stable even in the presence of large absorption. Furthermore, in the context of the linear response laws and causality, we analyze a vanishing absorption approximation, which is commonly used in wave scattering problems. We show that it is easy to violate causality in the frequency-domain by making the vanishing absorption approximation. We also develop an orders-of-scattering approximation, termed "screened cylindrical void/core" (SCV) approximation, for wave scattering from a large host cylinder containing N eccentrically embedded core cylinders. The SCV approximation is developed via separation of variables and a cluster T-matrix. We establish the limitations of the SCV approximation and it is in good agreement with the numerically-exact solution. Furthermore, we illustrate that the large host cylinder model with N cylindrical inclusions can be used to theoretically and experimentally investigate strong multiple scattering effects in random media, such as Anderson localization.

Yuffa, Alex J.

134

Electromagnetic Interference on Pacemakers  

PubMed Central

External sources, either within or outside the hospital environment, may interfere with the appropriate function of pacemakers which are being implanted all around the world in current medical practice. The patient and the physician who is responsible for follow-up of the pacing systems may be confronted with some specific problems regarding the various types of electromagnetic interference (EMI). To avoid these unwanted EMI effects one must be aware of this potential problem and need to take some precautions. The effects of EMI on pacemaker function and precautions to overcome some specific problems were discussed in this review article. There are many sources of EMI interacting with pacemakers. Magnetic resonance imaging creates real problem and should be avoided in pacemaker patients. Cellular phones might be responsible for EMI when they were held on the same side with the pacemaker. Otherwise they don't cause any specific type of interaction with pacemakers. Sale security systems are not a problem if one walks through it without lingering in or near it. Patients having unipolar pacemaker systems are prone to develop EMI because of pectoral muscle artifacts during vigorous active physical exercise.

Erdogan, Okan

2002-01-01

135

Electromagnetically driven peristaltic pump  

DOEpatents

An electromagnetic peristaltic pump apparatus may comprise a main body section having an inlet end and an outlet end and a flexible membrane which divides the main body section into a first cavity and a second cavity. The first cavity is in fluid communication with the inlet and outlet ends of the main body section. The second cavity is not in fluid communication with the first cavity and contains an electrically conductive fluid. The second cavity includes a plurality of electrodes which are positioned within the second cavity generally adjacent the flexible membrane. A magnetic field generator produces a magnetic field having a plurality of flux lines at least some of which are contained within the second cavity of the main body section and which are oriented generally parallel to a flow direction in which a material flows between the inlet and outlet ends of the main body section. A control system selectively places a voltage potential across selected ones of the plurality of electrodes to deflect the flexible membrane in a wave-like manner to move material contained in the first cavity between the inlet and outlet ends of the main body section.

Marshall, Douglas W. (Blackfoot, ID)

2000-01-01

136

Electromagnetism of Bacterial Growth  

NASA Astrophysics Data System (ADS)

There has been increasing concern from the public about personal health due to the significant rise in the daily use of electrical devices such as cell phones, radios, computers, GPS, video games and television. All of these devices create electromagnetic (EM) fields, which are simply magnetic and electric fields surrounding the appliances that simultaneously affect the human bio-system. Although these can affect the human system, obstacles can easily shield or weaken the electrical fields; however, magnetic fields cannot be weakened and can pass through walls, human bodies and most other objects. The present study was conducted to examine the possible effects of bacteria when exposed to magnetic fields. The results indicate that a strong causal relationship is not clear, since different magnetic fields affect the bacteria differently, with some causing an increase in bacterial cells, and others causing a decrease in the same cells. This phenomenon has yet to be explained, but the current study attempts to offer a mathematical explanation for this occurrence. The researchers added cultures to the magnetic fields to examine any effects to ion transportation. Researchers discovered ions such as potassium and sodium are affected by the magnetic field. A formula is presented in the analysis section to explain this effect.

Ainiwaer, Ailiyasi

2011-10-01

137

From GEM to electromagnetism  

NASA Astrophysics Data System (ADS)

In the first part of the present work, we focus on the theory of gravitoelectromagnetism (GEM), and we derive the full set of equations and constraints that the GEM scalar and vector potentials ought to satisfy. We discuss important aspects of the theory, such as the presence of additional constraints resulting from the field equations and gauge condition, the requirement of the time-independence of the vector potential and the emergence of additional terms in the expression of the Lorentz force. We also propose an alternative ansatz for the metric perturbations that is found to be compatible only with a vacuum configuration but evades several of the aforementioned obstacles. In the second part of this work, we pose the question of whether a tensorial theory using the formalism of General Relativity could re-produce the theory of Electromagnetism. We demonstrate that the full set of Maxwell's equations can be exactly re-produced for a large class of models, but the framework has several weak points common with those found in GEM.

Bakopoulos, A.; Kanti, P.

2014-06-01

138

Electromagnetic ion beam instabilities  

NASA Technical Reports Server (NTRS)

The linear theory of electromagnetic instabilities driven by an energetic ion beam streaming parallel to a magnetic field in a homogeneous Vlasov plasma is considered. Numerical solutions of the full dispersion equation are presented. At propagation parallel to the magnetic field, there are four distinct instabilities. A sufficiently energetic beam gives rise to two unstable modes with right-hand polarization, one resonant with the beam, the other nonresonant. A beam with sufficiently large T (perpendicular to B)/T (parallel to B) gives rise to the left-hand ion cyclotron anisotropy instability at relatively small beam velocities, and a sufficiently hot beam drives unstable a left-hand beam resonant mode. The parametric dependences of the growth rates for the three high beam velocity instabilities are presented here. In addition, some properties at oblique propagation are examined. It is demonstrated that, as the beam drift velocity is increased, relative maxima in growth rates can arise at harmonics of the ion cyclotron resonance for both right and left elliptically polarized modes.

Gary, S. P.; Foosland, D. W.; Smith, C. W.; Lee, M. A.; Goldstein, M. L.

1984-01-01

139

Electromagnetic unit fuel injector  

SciTech Connect

This patent describes an electromagnetic unit fuel injector of the type including a housing havine a pump cylinder therein; an externally actuated plunger reciprocable in the cylinder means to define therewith a pump chamber. The housing includes a valve body having a spray outlet at one end thereof for the discharge of fuel. An injection valve is movable in the valve body to control flow through the spray outlet. An inlet passage is in flow communication with the pump chamber and is connectable at its other end to a source of fuel. A pressure modulated servo chamber is in the housing. A spring means and a servo piston means operatively connected to the injection valve with the servo piston means being positioned so as to be acted on by the pressure of fuel in the servo chamber and a discharge passage in the housing connects the pump chamber to the spray outlet and to the servo chamber and has a throttle orifice controlling fuel flow to the servo chamber. The housing means further includes a drain passage means in flow communication at one end with the servo chamber and at its opposite end with a source of fuel at a predetermined pressure and a pressure sensitive control valve operatively positioned in the housing. A pull type solenoid is operatively supported in the housing means and a fuel passage means connectable is at one end to a source of fuel at a suitable supply pressure and at its other end being in operative flow communication with the pump chamber. The improvement wherein the control valve is in the form of a poppet valve and wherein the stepped bore includes an enlarged internal diameter portion next adjacent to the valve seat whereby the pressure of fuel in the annulus cavity can act against the head in a valve opening direction and wherein the force of the valve return spring is preselected so that the control valve is also operative as a pressure relief valve.

Deckard, J.I.

1986-02-25

140

Novel electromagnetic micropump  

NASA Astrophysics Data System (ADS)

The mergence of partial aspects and functional components of micro actuators and micro fluidic technology allows the development of complex micro systems, which are more and more interesting for MEMS application, especially for BioMEMS. This enormous potential is shown in this article showing the realization of an electro magnetic micro pump. The basic build-up consists of a polymer magnet integrated into a pump chamber of a fluidic PDMS device, which is located above a double layer micro coil. By applying a current, the polymer magnet performs a bidirectional movement, which results in a pumping effect by the two arranged passive check valves being perpendicularly arranged to the flow channels. The valve membrane is flexible and opens the channel towards the flow direction. The advantage of this configuration is that leakage can be avoided by the special geometrical configuration of the fluid chamber and the valves. The fabrication process includes UV depth lithography using AZ9260, electroforming of copper for the double layer spiral coil and Epon SU-8 for insulation, embedding and manufacturing of the valve seat. Furthermore, the fluidic devices are realized by replica molding of PDMS using a multilayer SU-8 master. Furthermore, a new technology for realizing micro polymer magnets was optimized and deployed. Using these fabrication processes, a magnetic micro actuator has already been developed based on the movable plunger principle, which forms the basic set-up of the micro pump. This actuator is monolithically fabricated and successfully tested. In addition, the fluidic system of the micro pump was successfully fabricated and tested. In order to connect the valve seats based on SU-8 to the PDMS fluidic chamber and the valve lips, a special bonding process was developed. The combination of the fluidic system with the electromagnetic part is currently under investigation. The dimension of the micro pump is about 10 × 6 × 3 mm.

Feldmann, M.; Demming, S.; Lesche, C.; Büttgenbach, S.

2007-12-01

141

78 FR 33633 - Human Exposure to Radiofrequency Electromagnetic Fields  

Federal Register 2010, 2011, 2012, 2013

...Exposure to Radiofrequency Electromagnetic Fields; Reassessment of Exposure to Radiofrequency Electromagnetic Fields Limits and Policies; Final...Exposure to Radiofrequency Electromagnetic Fields AGENCY: Federal...

2013-06-04

142

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

143

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

144

Binary black holes' effects on electromagnetic fields.  

PubMed

In addition to producing gravitational waves, the dynamics of a binary black hole system could induce emission of electromagnetic radiation by affecting the behavior of plasmas and electromagnetic fields in their vicinity. We here study how the electromagnetic fields are affected by a pair of orbiting black holes through the merger. In particular, we show how the binary's dynamics induce a variability in possible electromagnetically induced emissions as well as a possible enhancement of electromagnetic fields during the late-merge and merger epochs. These time dependent features will likely leave their imprint in processes generating detectable emissions and can be exploited in the detection of electromagnetic counterparts of gravitational waves. PMID:19792706

Palenzuela, Carlos; Anderson, Matthew; Lehner, Luis; Liebling, Steven L; Neilsen, David

2009-08-21

145

Electromagnetic jets from compact objects  

NASA Technical Reports Server (NTRS)

The possibility that at least some astrophysical jets are initially electromagnetic in origin is examined. Subsequent pick-up of ionization would convert such electromagnetic jets into hydrodynamic jets. In such a model, relativistic outflow is formed into highly collimated beams simply through the interaction with the surrounding medium. Forming jets under such general circumstances is encouraging in view of the range of scales that appear to be involved. The overall properties of such jets are largely determined by a single dimensionless parameter: the characteristic electrostatic potential drop rewritten as a particle Lorentz factor. Consequently, the determination of any one observable, such as the total power output, also determines the particle energy scale, the electromagnetic field strengths, etc.

Michel, F. Curtis

1987-01-01

146

Un-renormalized classical electromagnetism  

SciTech Connect

This paper follows in the tradition of direct-action versions of electromagnetism having the aim of avoiding a balance of infinities wherein a mechanical mass offsets an infinite electromagnetic mass so as to arrive at a finite observed value. However, the direct-action approach ultimately failed in that respect because its initial exclusion of self-action was later found to be untenable in the relativistic domain. Pursing the same end, this paper examines instead a version of electromagnetism wherein mechanical action is excluded and self-action is retained. It is shown that the resulting theory is effectively interacting due to the presence of infinite forces. A vehicle for the investigation is a pair of classical point charges in a positronium-like arrangement for which the orbits are found to be self-sustaining and naturally quantized.

Ibison, Michael [Institute for Advanced Studies at Austin, 4030 West Braker Lane, Suite 300, Austin, TX 78759 (United States)]. E-mail: ibison@earthtech.org

2006-02-15

147

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

148

Time reversal of electromagnetic waves.  

PubMed

We report the first experimental demonstration of time-reversal focusing with electromagnetic waves. An antenna transmits a 1-micros electromagnetic pulse at a central frequency of 2.45 GHz 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 to its initial source and is compressed in time. The quality of focusing is determined by the frequency bandwidth and the spectral correlations of the field within the cavity. PMID:15169405

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

2004-05-14

149

Electromagnetic Models of Extragalactic Jets  

SciTech Connect

Relativistic jets may be confined by large-scale, anisotropic electromagnetic stresses that balance isotropic particle pressure and disordered magnetic field. A class of axisymmetric equilibrium jet models will be described and their radiative properties outlined under simple assumptions. The partition of the jet power between electromagnetic and mechanical forms and the comoving energy density between particles and magnetic field will be discussed. Current carrying jets may be recognized by their polarization patterns. Progress and prospects for measuring this using VLBI and GLAST observations will be summarized.

Lisanti, M.; Blandford, R.; /KIPAC, Menlo Park

2007-10-22

150

Electromagnetic Gun With Commutated Coils  

NASA Technical Reports Server (NTRS)

Proposed electromagnetic gun includes electromagnet coil, turns of which commutated in sequence along barrel. Electrical current fed to two armatures by brushes sliding on bus bars in barrel. Interaction between armature currents and magnetic field from coil produces force accelerating armature, which in turn, pushes on projectile. Commutation scheme chosen so magnetic field approximately coincides and moves with cylindrical region defined by armatures. Scheme has disadvantage of complexity, but in return, enables designer to increase driving magnetic field without increasing armature current. Attainable muzzle velocity increased substantially.

Elliott, David G.

1991-01-01

151

Electromagnetic interference in critical care.  

PubMed

Mobile communication and wireless data transmission are playing an increasing role in health care. Reports describing medical device malfunction related to cellular phones have raised awareness about the problem of electromagnetic interference. Although initial institutional responses were to ban cellular devices in hospitals, these restrictions are relaxing as the knowledge base in this area expands. Medical device malfunction is extremely rare if the distance from the transmitting device is greater than 1 m. This article reviews the current understanding of electromagnetic interference as it applies to the technology-rich critical care environment. PMID:16990096

Lapinsky, Stephen E; Easty, Anthony C

2006-09-01

152

In-Line, Concurrent Electromagnetic Beam Analyzer.  

National Technical Information Service (NTIS)

This invention relates generally to electromagnetic radiation technology and more specifically to electromagnetic beam diagnostics. An in-line concurrent diagnostic analyzer for laser beams is described. An aperture mirror splits the initial laser beam in...

F. Mako J. A. Pasour

1984-01-01

153

Parametric Instabilities of Electromagnetic Waves in Plasmas.  

National Technical Information Service (NTIS)

A simple formalism for the parametric decay of an intense, coherent electromagnetic wave into an electrostatic wave and scattered electromagnetic waves in a homogeneous plasma is developed. Various instabilities including Brillouin and Raman backscatterin...

J. F. Drake P. K. Kaw Y. C. Lee G. Schmidt C. S. Liu

1973-01-01

154

Hybrid Techniques for Complex Aerospace Electromagnetics Problems.  

National Technical Information Service (NTIS)

Important aerospace electromagnetics problems include the evaluation of antenna performance on aircraft and the prediction and control of the aircraft's electromagnetic signature. Due to the ever increasing complexity and expense of aircraft design, aeros...

J. Aberle

1993-01-01

155

Electromagnetic Gage Techniques for Dynamic Tensile Fracture.  

National Technical Information Service (NTIS)

Electromagnetic gage techniques are ideally suited to measuring in-material motions during the dynamic fracture of many materials. As electromagnetic sensing elements can be constructed of any conducting material and are not affected by micro-deformation ...

C. Young

1988-01-01

156

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

157

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

158

Development of a Strong Electromagnet Wiggler.  

National Technical Information Service (NTIS)

The Strong Electromagnet (SEM) wiggler is a permanent magnet-assisted electromagnet under development at the Lawrence Livermore National Laboratory (LLNL) as part of the Induction Linac Free-Electron-Laser (IFEL) program. This concept uses permanent magne...

M. J. Burns G. A. Deis R. H. Holmes R. D. Van Maren K. Halbach

1987-01-01

159

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

160

Open tools for electromagnetic simulation programs  

Microsoft Academic Search

Purpose – The aim of the paper is to propose three computer tools to create electromagnetic simulation programs: GiD, Kratos and EMANT. Design\\/methodology\\/approach – The paper presents a review of numerical methods for solving electromagnetic problems and presentation of the main features of GiD, Kratos and EMANT. Findings – The paper provides information about three computer tools to create electromagnetic

Javier Mora; Rubén Otín; Pooyan Dadvand; Enrique Escolano; Miguel A. Pasenau; Eugenio Oñate

2006-01-01

161

Three-phase electromagnetic AC motors  

Microsoft Academic Search

Advanced three-phase electromagnetic ac motors based on electromagnetic gate-inductor motors are proposed. The concept of\\u000a development and the constructive scheme of a three-phase electromagnetic ac motor are given. Advantages of the proposed motors\\u000a compared to asynchronous motors are shown.

Yu. V. Smirnov

2009-01-01

162

The Future of Electromagnetic Field Litigation  

Microsoft Academic Search

This Article explores the dynamics and complexity of the electromagnetic field controversy. Presently, there are many unanswered questions with respect to the effects electromagnetic radiation has on people who live or work near power lines. This Article examines the state of domestic and international scientific evidence that exists regarding the risks of electromagnetic radiation. Ultimately, the Article concludes that although

Michael C. Anibogu

1998-01-01

163

Noninvasive valve monitor using alternating electromagnetic field  

Microsoft Academic Search

One or more electrical coils are carefully located on the outside of a valve body. An alternating current passing through the coil(s) results in an alternating electromagnetic field being transmitted into the valve body and valve internals. The electromagnetic field varies in intensity and polarity in the valve. As the position of a valve internal part is changed, the electromagnetic

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

1993-01-01

164

Some Student Conceptions of Electromagnetic Induction  

ERIC Educational Resources Information Center

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

Thong, Wai Meng; Gunstone, Richard

2008-01-01

165

Electromagnetic Scattering by Charged Dust Aggregates  

Microsoft Academic Search

Dust aggregates in plasma charge, which makes it difficult to study the propagation of electromagnetic wave in it. While in order to study the influence of charged dust to the space detection, some work must be done for the electromagnetic characteristic of it. Based on discrete dipole approximation (DDA), electromagnetic scattering characteristic of charged dust aggregates is studied. At the

Haiying Li; Zhensen Wu; Guangchi Wang

2006-01-01

166

Parallelisation of electromagnetic simulation codes  

Microsoft Academic Search

In this paper results obtained from the parallelisation of existing 3D electromagnetic Finite Element codes within the ESPRIT HPCN project PARTEL are presented. The parallelisation procedure, based on the Bulk Synchronous Parallel approach, is outlined and the encouraging results obtained in terms of speed-up on some industrially significant test cases are described and discussed

R. Janssen; M. Dracopoulos; K. Parrott; E. Slessor; P. Alotto; P. Molfino; M. Nervi; J. Simkin

1998-01-01

167

Experimental electromagnetic launchers at MRL  

Microsoft Academic Search

The design and construction of small caliber rail-type electromagnetic launchers are described. Bore sizes of 48 sq mm or 100 sq mm cross section are used and barrel lengths vary from 200 mm to 2 m. Sufficient information is provided to reproduce any of the devices, all of which are proving to be very useful experimentally. Examples of results are

A. J. Bedford; G. A. Clark; Y. C. Thio

1983-01-01

168

Electromagnetic Mass Difference of Kaons.  

National Technical Information Service (NTIS)

Using the algebra of currents, modified Weinberg sum rules, and the tadpole model of Coleman, Glashow, and Schnitzer, a calculation is made of the kaon electromagnetic mass difference in the soft-kaon limit to be -3.9 plus or minus 0.6 MeV, in excellent a...

C. L. Cook L. E. Evans M. Y. Han N. R. Lipshutz N. Straumann

1968-01-01

169

Power electronics and electromagnetic compatibility  

Microsoft Academic Search

Recently, power electronics has become the dominant factor in the deterioration of the electromagnetic environment, causing declining quality of line power and increasing level of conducted EMI. This paper reviews the fundamentals of EMC in power electronics, including the terminology and categories of EMC, the propagation and generation of low-frequency and high-frequency disturbances, and the various agency regulations. The paper

R. Redl

1996-01-01

170

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

171

GROUND AND AIRBORNE ELECTROMAGNETIC METHODS  

Microsoft Academic Search

1. SUMMARY Electromagnetic (EM) methods are used to map variations in electrical properties. The main physical property involved in these methods is inductive electrical conductivity, which is a measure of how easily electrical current can pass through a material. Conductivity is a complex function of several variables including the conductivity of solid materials, conductivity of pore fluids, porosity, arrangement of

172

Electromagnetic fields and public health  

Microsoft Academic Search

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,

T. E. Aldrich; C. E. Easterly

1987-01-01

173

Gravitational Analog of the Electromagnetic  

Microsoft Academic Search

The gravitational analog of the electromagnetic Poynting vector is constructed us- ing the field equations of general relativity in the Hilbert gauge. It is found that when the gravitational Poynting vector is applied to the solution of the linear mass quadrupole oscillator, the correct gravitational quadrupole radiation flux is ob- tained. Further to this, the Maxwell-like gravitational Poynting vector gives

Poynting Vector

174

Electromagnetic Interaction of Dual Systems  

Microsoft Academic Search

We introduce the electromagnetic interaction of dual models by means of a generalized minimum-interaction principle. It leads to a conserved current and a gauge-invariant theory. Unfortunately, the strong gauge conditions are preserved only for on-mass-shell photons, which leads to unphysical poles in k.k'.

P. Ramond

1972-01-01

175

Analysis of Units in Electromagnetism.  

National Technical Information Service (NTIS)

To define a system of electromagnetic units uniquely, six basic quantities must be chosen. Maxwell's equations are derived in a general form, independent of any particular choice of the six basic quantities. It is shown that the MKSA-formulation of the fi...

F. Primdahl

1971-01-01

176

Electromagnetic response of unconventional superconductors  

Microsoft Academic Search

We derive the current response to the linearly polarized electromagnetic field incident normally on the specular surface of a clean nonconventional superconductor with orbital spontaneous magnetization parallel to the crystal axis and perpendicular to the crystal surface. The result includes the usual part known from the theory of conventional superconductivity, as well as the magneto-optical term typical for superconductors with

V. P. Mineev

2008-01-01

177

Electromagnetic vortices in a plasma  

Microsoft Academic Search

It is shown that electromagnetic solitary vortices (with a nonpotential electric field) can exist in a plasma. Vortices of two types are discussed: Alfven and ballooning. An Alfven vortex can exist in a homogeneous plasma immersed in a homogeneous magnetic field. A ballooning vortex is predicted for a plasma with homogeneous density immersed in crossed magnetic and gravitational fields.

G. D. Aburdzhaniia; A. B. Mikhailovskii; O. G. Onishchenko; S. E. Sharapov; A. P. Churikov

1984-01-01

178

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

179

Proposed electromagnetic wave energy converter  

NASA Technical Reports Server (NTRS)

Device converts wave energy into electric power through array of insulated absorber elements responsive to field of impinging electromagnetic radiation. Device could also serve as solar energy converter that is potentially less expensive and fragile than solar cells, yet substantially more efficient.

Bailey, R. L.

1973-01-01

180

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

181

Explanations, Education, and Electromagnetic Fields.  

ERIC Educational Resources Information Center

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

Friedman, Sharon M.

182

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

183

Coupling Electromagnetism to Global Charge  

NASA Astrophysics Data System (ADS)

It is shown that an alternative to the standard scalar quantum electrodynamics (QED) is possible. In this new version, there is only global gauge invariance as far as the charged scalar fields are concerned, although local gauge invariance is kept for the electromagnetic field. The electromagnetic coupling has the form j?(A? +??B) where B is an auxiliary field and the current j? is A? independent, so that no "sea gull terms" are introduced. As a consequence of the absence of sea gulls, it is seen that no Klein paradox appears in the presence of a strong square well potential. In a model of this kind, spontaneous breaking of symmetry does not lead to photon mass generation, instead the Goldstone boson becomes a massless source for the electromagnetic field. When spontaneous symmetry breaking takes place infrared questions concerning the theory and generalizations to global vector QED are discussed. In this framework, Q-Balls and other nontopological solitons that owe their existence to a global U(1) symmetry can be coupled to electromagnetism and could represent multiply charged particles now in search in the large hadron collider (LHC). Furthermore, we give an example where an "Emergent" Global Scalar QED can appear from an axion-photon system in an external magnetic field. Finally, formulations of Global Scalar QED that allow perturbative expansions without sea gulls are developed.

Guendelman, E. I.

2013-12-01

184

Electromagnetic electron temperature anisotropy instabilities  

NASA Technical Reports Server (NTRS)

This paper considers electromagnetic Vlasov instabilities driven by electron temperature anisotropies in a homogeneous, nonrelativistic magnetized plasma. Numerical solutions of the full linear dispersion equation for bi-Maxwellian distribution functions and instabilities propagating parallel to the magnetic field are presented. Parametric dependences of the maximum growth rates of the electron fire hose and whistler anisotropy instabilities are given.

Gary, S. P.; Madland, C. D.

1985-01-01

185

Therapeutic applications of electromagnetic power  

Microsoft Academic Search

The use of electromagnetic (EM) power for therapeutic applications has existed since EM sources have been available to man. Physical medicine has been a major user of both shortwave (27.33 MHz) and microwave (2450 MHz) diathermy over the decades in which the EM power has been used to heat deep tissues for stimulating various medically beneficial physiologic responses in the

ARTHUR W. GUY; JUSTUS F. LEHMANN; JERRY B. STONEBRIDGE

1974-01-01

186

Electromagnetic hypersensitivity: Fact or Fiction?  

Microsoft Academic Search

As the prevalence of wireless telecommunication escalates throughout the world, health professionals are faced with the challenge of patients who report symptoms they claim are connected with exposure to some frequencies of electromagnetic radiation (EMR). Some scientists and clinicians acknowledge the phenomenon of hypersensitivity to EMR resulting from common exposures such as wireless systems and electrical devices in the home

Stephen J. Genuis; Chris Lipp

187

Millimeter wave electromagnetic measurement techniques  

Microsoft Academic Search

This report presents the results of studies to develop the rationale for electromagnetic measurement techniques for use in the EMC evaluation of millimeter wave (MMW) communication-electronic equipment and systems. In the development of this rationale, seven basic tasks were performed. Under the first task, the EMC\\/EMI data requirements for MMW equipments and systems were established to provide a clear definition

E. E. Donaldson; J. C. Mantovani; G. B. Melson; D. W. Acree

1982-01-01

188

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

189

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

190

Strong permanent magnet-assisted electromagnetic undulator  

SciTech Connect

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.

Halbach, Klaus (Berkeley, CA)

1988-01-01

191

Hardening against a combined electromagnetic threat  

NASA Astrophysics Data System (ADS)

Hardening against the electromagnetic environment is usually done by considering each threat separately. In recent years, there has been an increasing interest in methods for unifying electromagnetic standards and procedures to simplify the design and testing of hardening techniques. This approach is appealing as it could reduce the cost of system design as well as the cost of testing. The objective of this paper is twofold: firstly, to assess the feasibility of combining the various electromagnetic threats to simplify the design of electromagnetic protection; and secondly, to assess the feasibility of using a single test, or at least a minimum number of tests, to verify the electromagnetic hardness of a system.

Dion, M.; Gardner, C.; Kashyap, S.

1995-03-01

192

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

193

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

194

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

2013-07-12

195

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

196

Laminated electromagnetic pump stator core  

DOEpatents

A stator core for an electromagnetic pump includes a plurality of circumferentially abutting tapered laminations extending radially outwardly from a centerline axis to collectively define a radially inner bore and a radially outer circumference. Each of the laminations includes radially inner and outer edges and has a thickness increasing from the inner edge toward the outer edge to provide a substantially continuous path adjacent the circumference. This pump is used in nuclear fission reactors. 19 figs.

Fanning, A.W.

1995-08-08

197

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

198

Electromagnetic separation of actinide isotopes  

Microsoft Academic Search

This report describes the design and technical characteristics of the electromagnetic mass-separator S-2 VNIIEF employed in the production of highly enriched isotopes of heavy actinide elements with a small relative difference of mass numbers. The mass-separator S-2 provides highly enriched isotopes in amounts adequate for nuclear physics and applied investigations. The technological procedure is presented, as well as the operational

S. M. Abramychev; N. V. Balashov; S. P. Vesnovskii; V. N. Vjachin; V. G. Lapin; E. A. Nikitin; V. N. Polynov

1992-01-01

199

Electromagnetic scattering from biological tissue  

NASA Astrophysics Data System (ADS)

Based on the mathematical models of the experimentally fitted spectrum of index inhomogeneities, we analyze the electromagnetic field scattered from biological tissue. The resulting cross-spectral density matrices are expressed in spherical polar coordinates and the two-dimensional definition of polarization could be used. The results show that the polarization characteristics of the far scattered field depend closely on the types of the tissue.

Tong, Zhisong; Korotkova, Olga

2012-12-01

200

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

201

Electromagnetic response of unconventional superconductors  

Microsoft Academic Search

We derive the current response to the linearly polarized electromagnetic\\u000afield with finite frequency and wave vector incident normally on the specular\\u000asurface of a clean nonconventional superconductor with orbital spontaneous\\u000amagnetization parallel to the crystal axis and perpendicular to the crystal\\u000asurface. The result includes the usual part known from the theory of\\u000aconventional superconductivity and as well the

V. P. Mineev

2008-01-01

202

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

203

Teaching Electromagnetism Using Advanced Technologies  

NSDL National Science Digital Library

Michael Faraday was the first to realize that the shape of electromagnetic field lines is extraordinarily expressive of their dynamical effects. We can understand intuitively many things about the forces transmitted by the fields by looking at the topology of the field lines. This is especially true when the field lines are animated. This NSF-funded site has many examples of EM field lines.

Belcher, John

2003-10-10

204

Geometry of Electromagnetic null field  

Microsoft Academic Search

Summary  Electromagnetic tensor field can be divided into three classes according as (i) its eigen values are all different (ii) two\\u000a of its eigen values vanish (iii) all the eigen values vanish. In the first two classes a non-holonomic frame can be constructed\\u000a from its eigen-vectors and their inverses. Hlavatý (1958) showed using Line-Geometry that a non-holonomic frame can be constructed

R. S. Mishra

1963-01-01

205

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

206

Electromagnetic separation of actinide isotopes  

NASA Astrophysics Data System (ADS)

This report describes the design and technical characteristics of the electromagnetic mass-separator S-2 VNIIEF employed in the production of highly enriched isotopes of heavy actinide elements with a small relative difference of mass numbers. The mass-separator S-2 provides highly enriched isotopes in amounts adequate for nuclear physics and applied investigations. The technological procedure is presented, as well as the operational results over many years in the production of highly enriched isotopes of uranium, plutonium, americium and curium.

Abramychev, S. M.; Balashov, N. V.; Vesnovskii, S. P.; Vjachin, V. N.; Lapin, V. G.; Nikitin, E. A.; Polynov, V. N.

1992-08-01

207

Pulsed power for electromagnetic launching  

SciTech Connect

There are system advantages to producing power for electromagnetic propulsion by real-time generation rather than by a sequence of generation-storage-switching. The best type of generator for this purpose is the flux compression generator. Different types of flux compression generator which have been developed at Sandia National Laboratories are reviewed and their applications to electric launching are discussed. New experimental facilities for producing more powerful generators are described and cost comparisons are made.

Cowan, M

1980-12-01

208

Wind measurements by electromagnetic probes  

NASA Technical Reports Server (NTRS)

The emerging technology of electromagnetic probing of the atmosphere to measure winds used in a space vehicle ascent winds load calculations is presented. The frequency range, altitude, and resolution for the following probes are presented: lidars, microwave radars, and clear-air Doppler radars (popularly known as wind profilers). The electromagnetic probing of the atmosphere by clear-air radars and lasers is the new technology to supplement balloon-borne wind sensors used to determine ascent wind loads of space vehicles. The electromagnetic probes measure the wind velocity using the Doppler effect. This is the radar technology used in MSFC's Radar Wind Profiler, and is similar to the technology used in conventional Doppler systems except that the frequency is generally lower, antenna is bigger, and dwell time much longer. Designed for unattended and automated instrumentation in providing measurements of the wind in the troposphere, the profiler employs Doppler radar technology and is currently being put in operation at NASA Kennedy Space Center, Florida.

Susko, Michael

1988-01-01

209

Electromagnetic brake/clutch device  

NASA Astrophysics Data System (ADS)

An electromagnetic brake/clutch device includes a drive shaft supported by at least one bearing for transmitting torque, a housing, affixed to prevent its rotation, surrounding the drive shaft, and an electromagnetically activated device within the housing to selectively prevent and allow rotation of the drive shaft. The electromagnetically activated device includes a plurality of cammed rollers to prevent counter-clockwise rotation of the drive shaft. The drive shaft includes a circumferential disk and the housing includes a reaction ring for engagement with the plurality of cammed rollers. The plurality of cammed rollers are released from engagement with the circumferential disk and the reaction ring by a plurality of tripping mechanisms within the housing. The tripping action uses the locking force to act as a release force merely by changing the boundary conditions of the roller interface angles. The tripping mechanisms include trippers for disengaging the plurality of cammed rollers and an anvil shaped portion for providing lateral movement of the trippers. The plurality of cammed rollers is preloaded to engagement with the circumferential disk and reaction ring by a spring, and is located with respect to an adjacent tripping mechanism with another spring.

Vranish, John M.

1994-01-01

210

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

SciTech Connect

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

Palenzuela, Carlos [Canadian Institute for Theoretical Astrophysics (CITA), Toronto, Ontario M5S 3H8 (Canada); Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Berlin, D-14476 Golm (Germany); Lehner, Luis [Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5 (Canada); Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); Canadian Institute For Advanced Research (CIFAR), Cosmology and Gravity Program (Canada); Yoshida, Shin [Department of Earth Science and Astronomy, Graduate School of Arts and Sciences, University of Tokyo, Meguro, Tokyo 153-8902 (Japan)

2010-04-15

211

Gravito-electromagnetic resonances in Minkowski space  

NASA Astrophysics Data System (ADS)

We consider the interaction between gravitational and electromagnetic radiation propagating on a Minkowski background and look into the effects of the former upon the latter. Not surprisingly, the coupling between these two sources leads to gravitationally driven electromagnetic waves. At the second perturbative level, the driving force appears as the superposition of two waves, the properties of which are decided by the initial conditions. We find that the Weyl-Maxwell interaction typically leads to electromagnetic beatlike signals and, in some cases, to the resonant amplification of the driven electromagnetic wave. For physically reasonable initial conditions, we show that these resonances imply a linear (in time) growth for the amplitude of the electromagnetic signal, with the overall amplification also depending on the strength of the driving gravity wave. Finally, we provide order-of-magnitude estimates of the achieved amplification by applying our analysis to astrophysical environments where both gravitational and electromagnetic waves are expected to coexist.

Kouretsis, Alexandros P.; Tsagas, Christos G.

2013-08-01

212

Electromagnetic coupling of high-altitude, nuclear electromagnetic pulses  

NASA Astrophysics Data System (ADS)

The vulnerability of complete military electronics systems to high-altitude electromagnetic pulses (HEMP) is assessed. Component and subsystem susceptibility is identified by focusing on one, two, and possibly three-dimensional computer models that include the major physical phenomena as represented, for example, by heat and electronic transport equations. Probabilistic failure analysis is applied to identify system vulnerabilities and to point the way to effective hardening. In order to assess system coupling with HEMP, an attempt is made to achieve a phenomenological understanding based on a multifaceted, complementary approach that combines analytical, computational, and experimental techniques, including scale-model tests. Current work on coupling phenomenology is described.

1984-11-01

213

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

214

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

215

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

2009-06-12

216

Manager's Role in Electromagnetic Interference (EMI) Control  

NASA Technical Reports Server (NTRS)

This presentation captures the essence of electromagnetic compatibility (EMC) engineering from a project manager's perspective. It explains the basics of EMC and the benefits to the project of early incorporation of EMC best practices. The EMC requirement products during a project life cycle are identified, along with the requirement verification methods that should be utilized. The goal of the presentation is to raise awareness and simplify the mystique surrounding electromagnetic compatibility for managers that have little or no electromagnetics background

Sargent, Noel B.; Lewis, Catherine C.

2013-01-01

217

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

218

Thin sheet casting with electromagnetic pressurization  

DOEpatents

An apparatus, method and system for the casting of thin strips or strips of metal upon a moving chill block that includes an electromagnet located so that molten metal poured from a reservoir onto the chill block passes into the magnetic field produced by the electromagnet. The electromagnet produces a force on the molten metal on said chill block in the direction toward said chill block in order to enhance thermal contact between the molten metal and the chill block.

Walk, Steven R. (Winterport, ME); Slepian, R. Michael (Pittsburgh, PA); Nathenson, Richard D. (Pittsburgh, PA); Williams, Robert S. (Fairfield, OH)

1991-01-01

219

Electromagnetic Imaging Methods for Nondestructive Evaluation Applications  

PubMed Central

Electromagnetic nondestructive tests are important and widely used within the field of nondestructive evaluation (NDE). The recent advances in sensing technology, hardware and software development dedicated to imaging and image processing, and material sciences have greatly expanded the application fields, sophisticated the systems design and made the potential of electromagnetic NDE imaging seemingly unlimited. This review provides a comprehensive summary of research works on electromagnetic imaging methods for NDE applications, followed by the summary and discussions on future directions.

Deng, Yiming; Liu, Xin

2011-01-01

220

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

221

Electromagnetic Interference Tests for Electronic Equipment.  

National Technical Information Service (NTIS)

The report prescribes procedures and techniques for measuring frequencies and amplitudes of the electromagnetic interference characteristics (emission, compatibility, and susceptibility) of electronic and electromechanical equipment, systems and subsystem...

1974-01-01

222

Calculation principles for a synchronous electromagnetic clutch  

NASA Technical Reports Server (NTRS)

A detailed explanation of the calculation principles, for a synchronous salient-pole electromagnetic clutch with lumped excitation windings is supplied by direct current. Practical recommendations are given.

Panasenkov, M. A.

1978-01-01

223

Noncontacting ultrasonic and electromagnetic HTS tape NDE  

SciTech Connect

Two noncontacting nondestructive evaluation techniques (electromagnetic and ultrasonic) for inspection of high temperature superconducting tapes are described. Results for Ag-clad BSCCO tapes are given.

Telschow, K.L.; Bruneel, F.W.; Walter, J.B.; Koo, L.S.

1996-10-01

224

Stimulated electromagnetic emissions by high-frequency electromagnetic pumping of the ionospheric plasma  

Microsoft Academic Search

A high frequency electromagnetic pump wave transmitted into the ionospheric plasma from the ground can stimulate electromagnetic radiation with frequencies around that of the ionospherically reflected pump wave. The numerous spectral features of these stimulated electromagnetic emissions (SEE) and their temporal evolution on a wide range of time scales are reviewed and related theoretical, numerical, and simulation results are discussed.

T. B. Leyser

2001-01-01

225

Quantum Electromagnetics - A Local-Ether Wave Equation Unifying Quantum Mechanics, Electromagnetics, and Gravitation  

Microsoft Academic Search

The theory of Quantum Electromagnetics presents a wave equation for electromagnetic and matter waves [1]. A fundamental feature entirely different from the principle of relativity is that the position vector and the time derivative in the wave equation are referred uniquely to the proposed local-ether frame. For electromagnetic wave, the local-ether wave equation accounts for a wide variety of propagation

Ching-Chuan Su

2002-01-01

226

Electromagnetic effects on transportation systems  

SciTech Connect

Electronic and electrical system protection design can be used to eliminate deleterious effects from lightning, electromagnetic interference, and electrostatic discharges. Evaluation of conventional lightning protection systems using advanced computational modeling in conjunction with rocket-triggered lightning tests suggests that currently used lightning protection system design rules are inadequate and that significant improvements in best practices used for electronic and electrical system protection designs are possible. A case study of lightning induced upset and failure of a railway signal and control system is sketched.

Morris, M.E.; Dinallo, M.A.

1996-05-01

227

Electromagnetic Transients Program (EMTP) primer  

NASA Astrophysics Data System (ADS)

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 be the single most important enhancement to the EMTP. The Primer is an EMTP training manual for new users. It includes introductory material and eleven sample studies so that the reader can learn by the case study method. The Primer is part of a series of new EMTP user manuals which covers program operation, theory, and application guide lines.

Mauser, S. F.; McDermott, T. E.

1985-09-01

228

Localized transmission of electromagnetic energy  

SciTech Connect

Novel electromagnetic directed-energy pulse train (EDEPT) solutions of Maxwell's equations have been obtained. One particular solution, the modified-power-spectrum (MPS) pulse, will be described in detail. EDEPT's such as the MPS pulses, can be tailored to give localized energy transmission along a specified direction in space that is significantly improved over conventional diffraction-limited beams. Moreover, they represent fields that recover their initial amplitudes along the direction of propagation at extremely large distances from their initial location. These EDEPT solutions are not physically pathological and can be reconstructed from causal Green's functions. In fact, these fields appear to be launchable from finite-aperture antennas.

Ziolkowski, R.W.

1989-02-15

229

Electromagnetic properties of massive neutrinos  

SciTech Connect

The vertex function for a virtual massive neutrino is calculated in the limit of soft real photons. A method based on employing the neutrino self-energy operator in a weak external electromagnetic field in the approximation linear in the field is developed in order to render this calculation of the vertex function convenient. It is shown that the electric charge and the electric dipole moment of the real neutrino are zero; only the magnetic moment is nonzero for massive neutrinos. A fourth-generation heavy neutrino of mass not less than half of the Z-boson mass is considered as a massive neutrino.

Dobrynina, A. A., E-mail: aleksandradobrynina@rambler.ru; Mikheev, N. V.; Narynskaya, E. N. [Demidov Yaroslavl State University (Russian Federation)] [Demidov Yaroslavl State University (Russian Federation)

2013-10-15

230

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

231

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

232

Electromagnets 1: Turn on the Power. Science in a Box.  

ERIC Educational Resources Information Center

The article presents inexpensive activities to teach elementary school students about electromagnets. Students learn to make an electromagnet with a battery, nail, and wire, then different activities help them explore the difference between permanent magnets and electromagnets. (SM)

Whitman, Betsy Blizard

1992-01-01

233

Large-Scale Electromagnetic Simulation  

NASA Astrophysics Data System (ADS)

The dramatic increase in computational capability that has occurred over the last ten years has allowed fully electromagnetic simulations of large, complex, multidimensional systems to move progressively from impractical, to expensive, and recently, to routine and widespread. This is particularly the case for systems that require the motion of free charge to be self-consistently treated. Several simulation tools have been developed to solve Maxwell's equations for both time-dependent problems, using finite difference and finite volume techniques, and time-harmonic problems, using boundary integral and finite element techniques. When required, several tools provide for the self-consistent treatment of free charge by integrating the Lorentz force equation, typically using the Particle-In-Cell (PIC) method. These tools have found widespread use for many diverse applications, including high-current electron and ion diodes, magnetically insulated power transmission systems, high-power microwave oscillators, high-frequency digital and analog integrated circuit packages, microwave integrated circuit components, antenna systems, radar cross-section applications, and electromagnetic interaction with biological material. This paper will give a brief overview of the various techniques used for such simulations, including a discussion of the effect of the architectures of modern high-performance computers on the implementation of those techniques. Also, some of the many simulation tools that are available will be described. As time permits, examples from several application areas will be presented.

Seidel, David B.

1996-05-01

234

Millimeter Waves: Acoustic and Electromagnetic  

PubMed Central

This article is the presentation I gave at the D'Arsonval Award Ceremony on June 14, 2011 at the Bioelectromagnetics Society Annual Meeting in Halifax, Nova Scotia. It summarizes my research activities in acoustic and electromagnetic millimeter waves over the past 47 years. My earliest research involved acoustic millimeter waves, with a special interest in diagnostic ultrasound imaging and its safety. For the last 21 years my research expanded to include electromagnetic millimeter waves, with a special interest in the mechanisms underlying millimeter wave therapy. Millimeter wave therapy has been widely used in the former Soviet Union with great reported success for many diseases, but is virtually unknown to Western physicians. I and the very capable members of my laboratory were able to demonstrate that the local exposure of skin to low intensity millimeter waves caused the release of endogenous opioids, and the transport of these agents by blood flow to all parts of the body resulted in pain relief and other beneficial effects.

Ziskin, Marvin C.

2012-01-01

235

Electromagnetic wave energy conversion research  

NASA Technical Reports Server (NTRS)

Known electromagnetic wave absorbing structures found in nature were first studied for clues of how one might later design large area man-made radiant-electric converters. This led to the study of the electro-optics of insect dielectric antennae. Insights were achieved into how these antennae probably operate in the infrared 7-14um range. EWEC theoretical models and relevant cases were concisely formulated and justified for metal and dielectric absorber materials. Finding the electromagnetic field solutions to these models is a problem not yet solved. A rough estimate of losses in metal, solid dielectric, and hollow dielectric waveguides indicates future radiant-electric EWEC research should aim toward dielectric materials for maximum conversion efficiency. It was also found that the absorber bandwidth is a theoretical limitation on radiant-electric conversion efficiency. Ideally, the absorbers' wavelength would be centered on the irradiating spectrum and have the same bandwith as the irradiating wave. The EWEC concept appears to have a valid scientific basis, but considerable more research is needed before it is thoroughly understood, especially for the complex randomly polarized, wide band, phase incoherent spectrum of the sun. Specific recommended research areas are identified.

Bailey, R. L.; Callahan, P. S.

1975-01-01

236

Dielectric detection by an electromagnetic cavity method  

Microsoft Academic Search

A method to screen for flammable and explosive materials in bottles by electromagnetic measurement is described. The technique makes use of an aluminum cavity having strong electromagnetic resonances in the radio wave band. An object inserted into the cavity changes the internal field configuration, and causes small, but measurable shifts in the resonant frequencies. The response depends on the electrical

James C. Weatherall; Howard F. Beckley; Joseph A. Gatto

2004-01-01

237

Engineering electromagnetic metamaterials and methanol fuel cells  

Microsoft Academic Search

Electromagnetic metamaterials represent a group of artificial structures, whose dimensions are smaller than subwavelength. Due to electromagnetic metamaterials' collective response to the applied fields, they can exhibit unprecedented properties to fascinate researchers' eyes. For instance, artificial magnetism above terahertz frequencies and beyond, negative magnetic response, and artificial plasma lower than ultraviolet and visible frequencies. Our goal is to engineer those

Tajen Yen

2005-01-01

238

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

239

High order methods for electromagnetics simulation  

Microsoft Academic Search

Higher order methods in electromagnetics are of interest to the PIC community in modeling electromagnetic wave propagation in cavities. It is believed that high order numerical methods have advantages over lower order methods as they can produce equivalently accurate solutions at lower resolution and thus potentially at lower computational cost. In this paper we present the algorithm and result of

John Loverich; Ammar Hakim

2007-01-01

240

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

241

Electromagnetic Simulation Studies of Photocathode Sources  

Microsoft Academic Search

We present the results of electromagnetic simulation studies on space-charge dominated electron beams produced by photocathode sources. In particular, we demonstrate the computational requirements on the Green's function based simulation code IRPSS (Indiana Rf Photocathode Source Simulator) for obtaining relative space-charge electromagnetic field errors of at most 1%, and show how these fields compare with electrostatic based field solver methods.

Mark Hess; Chong Shik Park

2007-01-01

242

The ELF-I augmented electromagnetic launcher  

Microsoft Academic Search

Augmenting an electromagnetic launcher barrel with one or more turns can theoretically increase the launcher system performance more than twice that of a simple EML. This is accomplished by increasing the amount of magnetic flux in the bore and thus increasing the electromagnetic accelerating force. The potential for augmented barrels had yet to be evaluated, therefore a one meter long

D. A. Fikse; J. L. Wu; Y. C. Thio

1984-01-01

243

Electromagnetic unidirectionality in magnetic photonic crystals  

Microsoft Academic Search

We study the effect of electromagnetic unidirectionality, which can occur in magnetic photonic crystals under certain conditions. A unidirectional periodic medium, being perfectly transparent for an electromagnetic wave of certain frequency, ``freezes'' the radiation of the same frequency propagating in the opposite direction. One of the most remarkable manifestations of the unidirectionality is that while the incident radiation can enter

A. Figotin; I. Vitebskiy

2003-01-01

244

NASA Applications for Computational Electromagnetic Analysis  

NASA Technical Reports Server (NTRS)

Computational Electromagnetic Software is used by NASA to analyze the compatibility of systems too large or too complex for testing. Recent advances in software packages and computer capabilities have made it possible to determine the effects of a transmitter inside a launch vehicle fairing, better analyze the environment threats, and perform on-orbit replacements with assured electromagnetic compatibility.

Lewis, Catherine C.; Trout, Dawn H.; Krome, Mark E.; Perry, Thomas A.

2011-01-01

245

Electromagnetic fields: Biological and clinical aspects  

Microsoft Academic Search

Our entire biosphere is immersed in a sea of man-made electromagnetic fields (EMF). Occupational and public health data suggest that these fields may be a health hazard, possibly involving cancer and fetal loss. This paper reviews the history and pertinent physics of electromagnetic fields and presents evidence from the authors' work, and that of others, of biological interaction with living

F. L. Tabrah; S. Batkin

1991-01-01

246

Medical application of surface electromagnetic waves  

Microsoft Academic Search

Advantages of surface electromagnetic waves application in medicine, including increased efficiency and depth of energy penetration are shown. Two types of the electrodes for physiotherapy, based on slow-wave structures (applicators and radiators) are described. It is shown that varying deceleration and frequency can control electric and magnetic field penetration into body tissue. The new method of electromagnetic energy radiation into

Yuriy N. Pchelnikov; Valery A. Kholodnyi

1998-01-01

247

Color superconductivity and its electromagnetic manifestation  

Microsoft Academic Search

A collection of the physical observables, related to the electromagnetic properties of a nucleon, to investigate the non--perturbative quantum fluctuations in the strong interaction vacuum state under the influence of at least one close by (in energy density) color superconducting phase found in several QCD motivated model calculations, are studied. It is shown that the spontaneous breaking of the electromagnetic

S. Ying

1999-01-01

248

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 specific…

Albe, Virginie; Venturini, Patrice; Lascours, Jean

2001-01-01

249

Upper High School Students' Understanding of Electromagnetism  

ERIC Educational Resources Information Center

Although electromagnetism is an important component of upper secondary school physics syllabuses in many countries, there has been relatively little research on students' understanding of the topic. A written test consisting of 16 diagnostic questions was developed and used to survey the understanding of electromagnetism of upper secondary school…

Saglam, Murat; Millar, Robin

2006-01-01

250

Wavelets and electromagnetic power system transients  

Microsoft Academic Search

The wavelet transform is introduced as a method for analyzing electromagnetic transients associated with power system faults and switching. This method, like the fourier transform, provides information related to the frequency composition of a waveform, but it is more appropriate than the familiar Fourier methods for the non-periodic, wide-band signals associated with electromagnetic transients. It appears that the frequency domain

D. C. Robertson; O. I. Camps; J. S. Mayer; W. B. Gish

1996-01-01

251

The Teaching of Electromagnetism at University Level  

ERIC Educational Resources Information Center

Discusses different kinds of material presentation in the teaching of electromagnetism at the university level, including three "classical" approaches and the Keller personalized proctorial system. Indicates that a general introduction to generators and motors may be useful in an electromagnetism course. (CC)

Houldin, J. E.

1974-01-01

252

Plasma Diagnostics with Short Electromagnetic Pulses  

Microsoft Academic Search

The propagation of short electromagnetic pulses in an ionized medium and the reflection of transient pulses from bounded ionized regions is discussed. Analytical expressions for transient oscillations in reflected and propagated electromagnetic fields excited by a unidirectional pulse are derived for certain simple cases. The transient oscillations show a periodicity which is directly related to the plasma frequency and are

Hans J. Schmitt

1964-01-01

253

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

254

Passive vibration control via electromagnetic shunt damping  

Microsoft Academic Search

This work will present a new type of passive vibration control technique based on the concept of electromagnetic shunt damping. The proposed technique is similar to piezoelectric shunt damping, as an appropriately designed impedance is shunted across the terminals of the transducer. Theoretical and experimental results are presented for a simple electromagnetic mass spring damper system.

Sam Behrens; Andrew J. Fleming; S. O. Reza Moheimani

2005-01-01

255

Forward electromagnetic scattering models for sea ice  

Microsoft Academic Search

Recent advances in forward modeling of the electromagnetic scattering properties of sea ice are presented. In particular, the principal results include the following: (1) approximate calculations of electromagnetic scattering from multilayer random media with rough interfaces, based on the distorted Born approximation and radiative transfer (RT) theory; (2) comprehensive theory of the effective complex permittivity of sea ice based on

K. M. Golden; M. Cheney; Kung-Hau Ding; A. K. Fung; Thomas C. Grenfell; D. Isaacson; Jin Au Kong; S. V. Nghiem; J. Sylvester; P. Winebrenner

1998-01-01

256

Constraint propagation through electromagnetic interaction topologies  

NASA Astrophysics Data System (ADS)

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 system. A constraint based approach for the modelling of the electromagnetic interactions in the system is then described. The approach taken here subdivides the modelling task into: (1) the definition of the related physical topology; (2) constraining topological nodes with specific electromagnetic attributes; and (3) the propagation of the electromagnetic constraints to determine the probability of failure. The scheme has been implemented in Quintus Prolog on a Sun Sparcstation. The electromagnet topology is represented in Prolog using an object-oriented knowledge representation methodology. A small database containing some attributes of electromagnetic components found on the Canadian NSA helicopter was developed. A coarse topological decomposition of the helicopter was made and the attributes for the various components were entered. This tool was very useful in providing understanding of all the complex interaction paths existing in complex systems.

Lovetri, Joe; Graham, Darin P. W.

1990-08-01

257

Signal characteristics from electromagnetic cascades in ice  

NASA Astrophysics Data System (ADS)

We investigate the development of electromagnetic cascades in ice using a GEANT Monte Carlo simulation. We examine the Cherenkov pulse that is generated by the charge excess that develops and propagates with the shower. This study is important for the RICE experiment at the South Pole, as well as any test beam experiment which seeks to measure coherent Cherenkov radiation from an electromagnetic shower. .

Razzaque, Soebur; Seunarine, Surujhdeo; Besson, David Z.; McKay, Douglas W.

2001-07-01

258

Quantization of Electromagnetic Fields in Cavities  

NASA Technical Reports Server (NTRS)

A quantization procedure for the electromagnetic field in a rectangular cavity with perfect conductor walls is presented, where a decomposition formula of the field plays an essential role. All vector mode functions are obtained by using the decomposition. After expanding the field in terms of the vector mode functions, we get the quantized electromagnetic Hamiltonian.

Kakazu, Kiyotaka; Oshiro, Kazunori

1996-01-01

259

Electromagnetic concepts in mathematical representation of physics  

NSDL National Science Digital Library

This articles addresses the use of mathematics when studying the physics of electromagnetism. The authors focus on common electromagnetic concepts and their associated mathematical representation and arithmetical tools. The authors conclude that most students do not understand the significant aspects of physical situations and have difficulty using relationships and models specific to magnetic phenomenon.

Albe, Virginie; Venturini, Patrice; Lascours, Jean

2006-12-06

260

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

261

Electromagnetic Attenuation by Solid Particle Aerosols  

Microsoft Academic Search

Theories of electromagnetic attenuation by absorption and scattering from aerosols of solid particles were evaluated and experimentally verified. Particles having specific physical and morphological properties were tested to maximize the mass extinction coefficients of the aerosols in several bands of the electromagnetic spectrum. Particulate materials were chosen based on theoretical predictions and compatible aerosolization schemes were developed for each material.

Erica Ray Petersen

1991-01-01

262

AN ANISOTROPIC ELECTROMAGNETIC-ELASTIC ANALOGY  

Microsoft Academic Search

An analogy is exhibited between results for electromagnetic waves in linear media which are both electrically and magnetically anisotropic (crystals) and results for flnite amplitude elastic waves in deformed Mooney-Rivlin materials. More precisely, the results for elastic waves in deformed Mooney-Rivlin materials appear formally as a special case of the results for electromagnetic waves in electrically and magnetically anisotropic crystals.

Ph. Boulanger; M. Hayes; Departement de Mathematique

263

Electromagnetic acoustic resonance and materials characterization  

Microsoft Academic Search

This paper reviews the operation principles and several applications of electromagnetic acoustic resonance (EMAR). EMAR is an emerging ultrasonic spectroscopy technique for nondestructive and noncontact materials characterization, relying on the use of electromagnetic-acoustic transducers (EMATs) and the superheterodyne circuitry for processing the received reverberation signals excited by long radio-frequency (RF) bursts. The transduction occurs through the Lorentz force mechanism and,

Masahiko Hirao; Hirotsugu Ogi

1997-01-01

264

Electromagnetic bonding of plastics to aluminum  

NASA Technical Reports Server (NTRS)

Electromagnetic curing is used to bond strain gage to aluminum tensile bar. Electromagnetic energy heats only plastic/metal interface by means of skin effect, preventing degradation of heat-treated aluminum. Process can be easily applied to other metals joined by high-temperature-curing plastic adhesives.

Sheppard, A. T.; Silbert, L.

1980-01-01

265

Electromagnetic scattering by pyramidal and wedge absorber  

Microsoft Academic Search

Electromagnetic scattering from pyramidal and wedge absorbers used to line the walls of modern anechoic chambers is measured and compared with theoretically predicted values. The theoretical performance for various angles of incidence is studied. It is shown that a pyramidal absorber scatters electromagnetic energy more as a random rough surface does. The apparent reflection coefficient from an absorber wall illuminated

Brian T. Dewitt; Walter D. Burnside

1988-01-01

266

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

267

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

268

Noninvasive valve monitor using alternating electromagnetic field  

DOEpatents

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

Eissenberg, David M. (Oak Ridge, TN) [Oak Ridge, TN; Haynes, Howard D. (Knoxville, TN) [Knoxville, TN; Casada, Donald A. (Knoxville, TN) [Knoxville, TN

1993-01-01

269

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

270

Noninvasive valve monitor using alternating electromagnetic field  

DOEpatents

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

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

1993-03-16

271

Healthcare vulnerabilities to electromagnetic pulse.  

PubMed

The U.S. healthcare system is particularly vulnerable to the effects of electromagnetic pulse (EMP) attack because of the system's technological sophistication, but while national defense planners prepare for the considerable threat that EMP poses, there has been little or no recognition of this threat within the US healthcare community, and neither has there been any significant healthcare planning to deal with such an eventuality. Recognition of the risk presented by EMP, and advance institution of appropriate strategies to mitigate its effects on the healthcare system, could enable the preservation of much of that system's function in the face of EMP-related disruptions, and will greatly further all-hazards disaster preparations. PMID:19202885

Ross, Lenard H; Mihelic, F Matthew

2008-01-01

272

Electromagnetic scattering by impedance structures  

NASA Technical Reports Server (NTRS)

The scattering of electromagnetic waves from impedance structures is investigated, and current work on antenna pattern calculation is presented. A general algorithm for determining radiation patterns from antennas mounted near or on polygonal plates is presented. These plates are assumed to be of a material which satisfies the Leontovich (or surface impedance) boundary condition. Calculated patterns including reflection and diffraction terms are presented for numerious geometries, and refinements are included for antennas mounted directly on impedance surfaces. For the case of a monopole mounted on a surface impedance ground plane, computed patterns are compared with experimental measurements. This work in antenna pattern prediction forms the basis of understanding of the complex scattering mechanisms from impedance surfaces. It provides the foundation for the analysis of backscattering patterns which, in general, are more problematic than calculation of antenna patterns. Further proposed study of related topics, including surface waves, corner diffractions, and multiple diffractions, is outlined.

Balanis, Constantine A.; Griesser, Timothy

1987-01-01

273

Electromagnetic gating in ion channels.  

PubMed

There have been many attempts to develop a theoretical explanation of the phenomena of electromagnetic field interactions with biological systems. None of the reported efforts have been entirely successful in accounting for the observed experimental results, in particular with respect to the reports of interactions between extremely low frequency (ELF) magnetic fields and biological systems at ion cyclotron resonance frequencies. The approach used in this paper starts with the Lorentz force equation, but use is made of cylindrical co-ordinates and cylindrical boundary conditions in an attempt to more closely model the walls of an ion channel. The equations of motion of an ion that result from this approach suggest that the inside shape of the channel plus the ELF magnetic fields at specific frequencies and amplitudes could act as a gate to control the movement of the ion across the cell membrane. PMID:1282185

McLeod, B R; Liboff, A R; Smith, S D

1992-09-01

274

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

275

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

276

Ultrarelativistic electromagnetic pulses in plasmas  

NASA Technical Reports Server (NTRS)

The physical processes of a linearly polarized electromagnetic pulse of highly relativistic amplitude in an underdense plasma accelerating particles to very high energies are studied through computer simulation. An electron-positron plasma is considered first. 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 piston-like 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.

1981-01-01

277

Avalanche photodiodes for electromagnetic calorimeters  

NASA Astrophysics Data System (ADS)

Hamamatsu S8148 silicon avalanche photodiode (APD) working in proportional mode has been chosen as readout device for the PbWO 4 crystals in the barrel of the CMS electromagnetic calorimeter (ECAL). High hadron fluences strongly affect the main parameters of both the scintillation crystals and the silicon detectors. In this work, we offer a new zinc sulfide-silicon (ZnS-Si) isotype heterojunction APD structure that is able to operate in high-radiation levels. A Monte Carlo simulation code has been performed in order to compare the Hamamatsu S8148 and the ZnS-Si APD structures for the photons emitting from PbWO 4 crystal during 10 years of CMS operation. Based on this work, the performance of these two APD structures has been investigated.

Pilicer, Ercan; Kocak, Fatma; Tapan, Ilhan; Ahmetoglu (Afrailov), Muhitdin

2007-03-01

278

Electromagnetic modeling of plasmonic nanostructures  

NASA Astrophysics Data System (ADS)

In this thesis, plasmonic properties of metal nanostructures are investigated by electromagnetic simulations using the finite difference time domain (FDTD) method. Chapter 1 covers the background knowledge required to read this thesis. It talks about the fundamentals of the FDTD method, the physics of plasmonics and a brief description of photocatalysis. In chapter 2, we perform optimization of plasmonic nanoparticle geometries. An iterative optimization algorithm is used to determine the configuration of the nanoparticles that gives the maximum electric field intensity at the center of the cluster. We observe that the optimum configurations of these clusters have mirror symmetry about the axis of planewave propagation, but are otherwise non-symmetric and non-intuitive. The maximum field intensity is found to increase monotonically with the number nanoparticles in the cluster, producing intensities that are 2500 times larger than the incident electromagnetic field. In chapter 3, evaporated thin films are imaged with high resolution transmission electron microscopy (HRTEM), to reveal the structure of the semicontinuous metal island film with sub-nm resolution. The electric field distributions and the absorption spectra of these semicontinuous island film geometries are calculated using the finite difference time domain (FDTD) method and compared with the experimentally measured absorption spectra. In addition to that, we calculate the SERS enhancement factors and photocatalytic enhancement factors of these films. We also study the effect of annealing on these films, which results in a large reduction in electric field strength due to increased nanoparticle spacing. In chapter 4, we study the effects of surrounding nanoparticles on a plasmonic hot spot. From our simulations, we show that the surrounding film contributes significantly to the electric field intensity at the hot spot by focusing energy to it. Widening of the gap size causes a decrease in the intensity at the hot spot. However, these island-like nanoparticle hot spots are shown to be robust to gap size than nanoparticle dimer geometries, studied previously. In fact, the main factor in determining the hot spot intensity is the focusing effect of the surrounding nano-islands. In chapter 5, we demonstrate plasmon-enhanced photocatalytic water splitting, and reduction of CO2 with H2O to form hydrocarbon fuels. Under visible illumination, we observe enhancements of up to 66X in the photocatalytic splitting of water in TiO2 with the addition of Au nanoparticles. We also perform a systematic study of the mechanisms of Au nanoparticle/TiO 2-catalyzed photoreduction of CO2 and water vapor over a wide range of wavelengths. In this case, under visible light illumination, we observe a 24-fold enhancement in the photocatalytic activity due to the intense local electromagnetic fields created by the surface plasmons of the Au nanoparticles. Above the plasmon resonance, under ultraviolet radiation we observe a reduction in the photocatalytic activity. Electromagnetic simulations indicate that the improvement of photocatalytic activity in the visible range is caused by the local electric field enhancement near the TiO2 surface, rather than by the direct transfer of charge between the two materials. In chapter 6, I will talk about a method for fabricating arrays of plasmonic nanoparticles with separations on the order of 1nm using an angle evaporation technique. High resolution transmission electron microscopy (HRTEM) is used to resolve the small separations achieved between nanoparticles fabricated on thin SiN membranes. These nearly touching metal nanoparticles produce extremely high electric field intensities when irradiated with laser light. We perform surface enhanced Raman spectroscopy (SERS) a non-resonant dye molecule (p-ATP) deposited on the nanoparticle arrays using confocal micro-Raman spectroscopy. Our results show significant enhancement when the incident laser is polarized parallel to the axis of the nanoparticle pairs, whereas no enhancement is observed for the p

Pavaskar, Prathamesh

279

Electromagnetic Signatures of SMBH Coalescence  

NASA Technical Reports Server (NTRS)

When two supermassive black holes (SMBHs) approach within 1-10 mpc, gravitational wave (GW) losses begin to dominate the evolution of the binary, pushing the system to merge in a relatively small time. During this final inspiral regime, the system will emit copious energy in GWs, which should be directly detectable by pulsar timing arrays and space-based interferometers. At the same time, any gas or stars in the immediate vicinity of the merging 5MBHs can get heated and produce bright electromagnetic (EM) counterparts to the GW signals. We present here a number of possible mechanisms by which simultaneous EM and GW signals will yield valuable new information about galaxy evolution, accretion disk dynamics, and fundamental physics in the most extreme gravitational fields.

Schnittman, Jeremy

2012-01-01

280

Integrated Circuit Electromagnetic Immunity Handbook  

NASA Astrophysics Data System (ADS)

This handbook presents the results of the Boeing Company effort for NASA under contract NAS8-98217. Immunity level data for certain integrated circuit parts are discussed herein, along with analytical techniques for applying the data to electronics systems. This handbook is built heavily on the one produced in the seventies by McDonnell Douglas Astronautics Company (MDAC, MDC Report E1929 of 1 August 1978, entitled Integrated Circuit Electromagnetic Susceptibility Handbook, known commonly as the ICES Handbook, which has served countless systems designers for over 20 years). Sections 2 and 3 supplement the device susceptibility data presented in section 4 by presenting information on related material required to use the IC susceptibility information. Section 2 concerns itself with electromagnetic susceptibility analysis and serves as a guide in using the information contained in the rest of the handbook. A suggested system hardening requirements is presented in this chapter. Section 3 briefly discusses coupling and shielding considerations. For conservatism and simplicity, a worst case approach is advocated to determine the maximum amount of RF power picked up from a given field. This handbook expands the scope of the immunity data in this Handbook is to of 10 MHz to 10 GHz. However, the analytical techniques provided are applicable to much higher frequencies as well. It is expected however, that the upper frequency limit of concern is near 10 GHz. This is due to two factors; the pickup of microwave energy on system cables and wiring falls off as the square of the wavelength, and component response falls off at a rapid rate due to the effects of parasitic shunt paths for the RF energy. It should be noted also that the pickup on wires and cables does not approach infinity as the frequency decreases (as would be expected by extrapolating the square law dependence of the high frequency roll-off to lower frequencies) but levels off due to mismatch effects.

Sketoe, J. G.

2000-08-01

281

Modeling Electromagnetic Scattering From Complex Inhomogeneous Objects  

NASA Technical Reports Server (NTRS)

This software innovation is designed to develop a mathematical formulation to estimate the electromagnetic scattering characteristics of complex, inhomogeneous objects using the finite-element-method (FEM) and method-of-moments (MoM) concepts, as well as to develop a FORTRAN code called FEMOM3DS (Finite Element Method and Method of Moments for 3-Dimensional Scattering), which will implement the steps that are described in the mathematical formulation. Very complex objects can be easily modeled, and the operator of the code is not required to know the details of electromagnetic theory to study electromagnetic scattering.

Deshpande, Manohar; Reddy, C. J.

2011-01-01

282

Detection of electromagnetic waves using charged cantilevers  

NASA Astrophysics Data System (ADS)

We describe micromechanical structures that are capable of sensing both electrostatic fields and electromagnetic fields over a wide frequency range. Typically, sensing of electromagnetic waves is achieved with electrically conducting antennas, which despite the many advantages do not exhibit high sensitivity over a broad frequency range. An important aspect of our present work is that, in contrast to traditional antennas, the dimensions of micromechanical oscillators sensitive to electromagnetic waves can be much smaller than the wavelength. We characterized the micromechanical oscillators and measured responses to electric fields and estimated the performance limits by evaluating the signal-to-noise ratio theoretically and experimentally.

Datskos, P. G.; Lavrik, N. V.; Tobin, J. D.; Bowland, L. T.

2012-03-01

283

High order methods for electromagnetics simulation  

NASA Astrophysics Data System (ADS)

Higher order methods in electromagnetics are of interest to the PIC community in modeling electromagnetic wave propagation in cavities. It is believed that high order numerical methods have advantages over lower order methods as they can produce equivalently accurate solutions at lower resolution and thus potentially at lower computational cost. In this paper we present the algorithm and result of electromagnetic simulations of the crab cavity using a higher than second order numerical wave propagation algorithm. Ultimately this high order scheme will be implemented in the plasma code VORPAL where it will be tested on a variety of computational plasma problems.

Loverich, John; Hakim, Ammar

2007-11-01

284

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

285

Development of a strong electromagnet wiggler  

SciTech Connect

The Strong Electromagnet (SEM) wiggler is a permanent magnet-assisted electromagnet under development at the Lawrence Livermore National Laboratory (LLNL) as part of the Induction Linac Free-Electron-Laser (IFEL) program. This concept uses permanent magnets within the wiggler to provide a reverse bias flux in the iron and thus delay the onset of magnetic saturation. The electromagnet coils determine the wiggler field and operate at low current densities by virtue of their placement away from the midplane. We describe here the design approach used and test data from a 7-period wiggler prototype that includes curved pole tips to provide wiggle-plane focusing. 7 refs.

Burns, M.J.; Deis, G.A.; Holmes, R.H.; Van Maren, R.D.; Halbach, K.

1987-01-01

286

Development of the strong electromagnet wiggler  

SciTech Connect

The Strong Electromagnet (SEM) wiggler is a permanent magnet-assisted electromagnet under development at the Lawrence Livermore National Laboratory (LLNL) as part of the Induction Linac Free-Electron-Laser (IFEL) program. This concept uses permanent magnets within the wiggler to provide a reverse bias flux in the iron and thus delay the onset of magnetic saturation. The electromagnet coils determine th4e wiggler field and operate at low current densities by virtue of their placement away from the midplane. The authors describe the design approach used and test data from a 7-period wiggler prototype that includes curved pole tips to provide wiggler-plane focusing.

Burns, M.J.; Deis, G.A.; Holmes, R.H.; Van Maren, R.D.; Halbach, K.

1988-03-01

287

An AWE Implementation for Electromagnetic Analysis  

NASA Technical Reports Server (NTRS)

Although full wave electromagnetic systems are large and cumbersome to solve, typically only a few parameters, such as input impedance, S parameters, and far field pattern, are needed by the designer or analyst. A reduced order modeling of these parameters is therefore an important consideration in minimizing the the CPU requirements. The Asymptotic Waveform Evaluation (AWE) method is one approach to construct a reduced order model of the input impedance or other useful electromagnetic parameters. We demonstrate its application and validity when used in conjunction with the finite element method to simulate full wave electromagnetic problems.

Gong, Jian; Volakis, John L.

1996-01-01

288

Geant4 Electromagnetic Physics for LHC Upgrade  

NASA Astrophysics Data System (ADS)

In this work we present recent progress in Geant4 electromagnetic physics modelling, with an emphasis on the new refinements for the processes of multiple and single scattering, ionisation, high energy muon interactions, and gamma induced processes. The future LHC upgrade to 13 TeV will bring new requirements regarding the quality of electromagnetic physics simulation: energy, particle multiplicity, and statistics will be increased. The evolution of CPU performance and developments for Geant4 multi-threading connected with Geant4 electromagnetic physics sub-packages will also be discussed.

Ivanchenko, V. N.; Apostolakis, J.; Bagulya, A.; Bogdanov, A.; Grichine, V.; Incerti, S.; Ivantchenko, A.; Maire, M.; Pandola, L.; Pokorski, W.; Sawkey, D.; Schaelicke, A.; Schenk, M.; Schwarz, S.; Urban, L.; Geant4 electromagnetic physics working groups

2014-06-01

289

Reformulation of electromagnetic and gravito-electromagnetic equations for Lorentz system with octonion algebra  

NASA Astrophysics Data System (ADS)

In this paper, the real, complex octonion algebra and their properties are defined. The electromagnetic and gravito-electromagnetic equations with monopoles in terms of S and reference systems are presented in vector notations. Additionally, the duality transformations of gravito-electromagnetic situation for two reference systems are also represented. Besides, it is explained that Maxwell-like equations for gravito-electromagnetism are also invariant under Lorentz transformations. By introducing complex octonionic differential operator, a new generalized complex octonionic field term consisting of electromagnetic and gravito-electromagnetic components has been firstly suggested for Lorentz system. Afterwards, a complex octonionic source equation is obtained as in basic way, more compact and elegant notation. By defining a new complex octonionic general potential term, the field equation is attained once again. The components of complex octonionic field and wave equations are written in detailed for S and reference systems.

Tan??l?, Murat; Kansu, Mustafa Emre; Demir, Süleyman

2014-05-01

290

Reverberating chambers as sources of stochastic electromagnetic fields  

Microsoft Academic Search

Reverberating chambers are of recognized relevance in many EMC applications since they allow us to generate a reference electromagnetic statistical field. This paper investigates the electromagnetic field in reverberating chambers. Reverberating chambers are large overmoded cavities wherein a nonstationary electromagnetic field is present. This electromagnetic field is stochastic in nature; therefore, proper analytical tools need to be considered in order

Paolo Corona; Giuseppe Ferrara; Maurizio Migliaccio

1996-01-01

291

Alternating Iteration Method For Solving Monochromatic Electromagnetic Wave  

Microsoft Academic Search

This paper has studied solving monochromatic electromagnetic wave. Under such circumstances of axial symmetric and passive electromagnetic wave that is finite and differentiable on the symmetric axis, a new approximation theory and alternating iteration method are provided by using Maxwell equations. Out-of-axis electromagnetic wave can be expressed as series with the method. This series contains electromagnetic wave on the symmetric

Zi-Jun Li; Mian Liu; Gang Li; Ben-Ying Fang

2006-01-01

292

Active Vibration Control of Beam Using Electromagnetic Constrained Layer Damping  

Microsoft Academic Search

This paper investigates vibration control of beam through electro-magnetic constrained layer damping (EMCLD) which consists of electromagnet layer, permanent magnet layer and viscoelastic damping layer. When the coil of the electromagnet is electrified with proper control strategy, the electromagnet can exert magnetic force opposite to the direction of structural deformation so that the structural vibration is attenuated. A mathematical model

Niu Hongpan; Zhang Yahong; Zhang Xinong; Xie Shilin

2008-01-01

293

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

294

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

295

Calculation of electromagnetic force in electromagnetic forming process of metal sheet  

SciTech Connect

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

Xu Da; Liu Xuesong; Fang Kun; Fang Hongyuan [State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001 (China)

2010-06-15

296

Intrinsic Electromagnetic Solitary Vortices in Magnetized Plasma.  

National Technical Information Service (NTIS)

Several Rossby type vortex solutions constructed for electromagnetic perturbations in magnetized plasma encounter the difficulty that the perturbed magnetic field and the parallel current are not continuous on the boundary between two regions. We find tha...

J. Liu W. Horton

1986-01-01

297

Stepped Waveguide Electromagnetic Material Characterization Technique.  

National Technical Information Service (NTIS)

Electromagnetic material characterization is the process of determining the complex permittivity and permeability of a material. A new waveguide material measurement technique is developed to reduce test sample size requirements for low-frequency applicat...

S. P. Dorey

2004-01-01

298

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

299

Clutter Models for Subsurface Electromagnetic Applications.  

National Technical Information Service (NTIS)

Clutter models for subsurface electromagnetic applications are discussed with emphasis on tunnel detection applications. Random medium models are more versatile and require less detailed information than deterministic models. The Born approximation is use...

D. A. Hill

1989-01-01

300

Electromagnetic Interactions with Few Body Systems  

SciTech Connect

The current status of electromagnetic interactions with few-body systems is presented. Results of recent experiments and theoretical investigations are discussed. Comments are made on several experimental investigations planned for the near future.

R. Roy Whitney

1988-04-01

301

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

302

Calibrator for an Electromagnetically Braked Bicycle Ergometer.  

National Technical Information Service (NTIS)

The electromagnetically braked bicycle ergometer is frequently used in the exercise physiology laboratory as a source of known workload. Normally the accuracy of the device cannot be verified without returning it to the factory for recalibration, a costly...

R. P. Layton W. A. Tetrault

1982-01-01

303

High-Altitude Electromagnetic Pulse (HEMP) Testing.  

National Technical Information Service (NTIS)

This TOP provides methods for planning, providing instrumentation, and execution of testing Army/DOD equipment to determine the effects of Horizontal Component High Altitude Electromagnetic Pulse (HEMP) environment. The content includes facilities, instru...

2011-01-01

304

Relativistic Particle Motion in Nonuniform Electromagnetic Waves.  

National Technical Information Service (NTIS)

It is shown that a charged particle moving in a strong nonuniform electromagnetic wave suffers a net acceleration in the direction of the negative intensity gradient of the wave. Electrons will be expelled perpendicularly from narrow laser beams and vario...

G. Schmidt T. Wilcox

1973-01-01

305

Working principle of an electromagnetic wiping system  

NASA Astrophysics Data System (ADS)

In galvanizing lines, the gas knife wiping device works well for controlling the zinc coating thickness up to 2 to 3 m/s strip velocities. But for higher velocities, a strong liquid zinc splash risk forbids the gas pressure increase, which would be necessary to keep the same thickness control efficiency of the knives. That is why a complementary electromagnetic wiping system, whose purpose is to pre-wipe the liquid zinc before the gas knives take over, is presented here. After mentioning different kinds of AC and DC possible electromagnetic solutions, a DC field electromagnetic brake (EMB) system based on the use of permanent magnets is selected for a future experimental implementation. In order to better understand the electromagnetic and fluid mechanics phenomena, an analytical model and then different numerical models are presented here. These models show an interesting wiping effect on the liquid zinc, which seems promising for a future experimental pilot design. Figs 8, Refs 9.

Ernst, R.; Fautrelle, Y.; Bianchi, A.-M.; Iliescu, M.

2009-03-01

306

Electromagnetic Field Control and Optimization Using Metamaterials.  

National Technical Information Service (NTIS)

Transformation optics has shown the ability to cloak an object from incident electromagnetic radiation is possible. However, the material parameters are inhomogeneous, anisotropic, and, in some instances, singular at various locations. In order for a cloa...

J. S. McGuirk

2009-01-01

307

Vlasov Antenna Data for Electromagnetic Code Validation.  

National Technical Information Service (NTIS)

Measured antenna data is provided for validating computational electromagnetic (CEM) computer programs. The subject antenna is the Vlasov antenna, which is formed by cutting a hollow circular cylindrical waveguide at an oblique angle. Measurements are sho...

A. Greenwood K. Hendricks

2003-01-01

308

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.

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

1984-12-01

309

Frequency Domain Electromagnetic Sensor Array Development.  

National Technical Information Service (NTIS)

A laboratory prototype frequency domain electromagnetic induction sensor array suitable for simultaneous operation with an array of cesium vapor total field magnetometers has been designed and fabricated and has undergone limited bench testing. The design...

D. J. Wright

2007-01-01

310

Electromagnetic Pulse Interaction at a Dielectric Interface.  

National Technical Information Service (NTIS)

The research on pulsed electromagnetic beam fields is nearing completion with some rather interesting results. In particular, the rigorous angular spectrum representation of pulsed beam fields has been found to differ from the given by the simpler plane-w...

K. E. Oughstun

1989-01-01

311

Pulsed Electromagnetic Field System for Nondestructive Testing.  

National Technical Information Service (NTIS)

The device is for detecting subsurface irregularities in a metal sample. Pulsed electromagnetic fields of alternate long and short time duration are transmitted into the sample through a mask. A receiving coil detects the reflected pulsed fields from the ...

C. J. Renken

1966-01-01

312

Electromagnetic thrusters for spacecraft prime propulsion  

NASA Technical Reports Server (NTRS)

The benefits of electromagnetic propulsion systems for the next generation of US spacecraft are discussed. Attention is given to magnetoplasmadynamic (MPD) and arc jet thrusters, which form a subset of a larger group of electromagnetic propulsion systems including pulsed plasma thrusters, Hall accelerators, and electromagnetic launchers. Mission/system study results acquired over the last twenty years suggest that for future prime propulsion applications high-power self-field MPD thrusters and low-power arc jets have the greatest potential of all electromagnetic thruster systems. Some of the benefits they are expected to provide include major reductions in required launch mass compared to chemical propulsion systems (particularly in geostationary orbit transfer) and lower life-cycle costs (almost 50 percent less). Detailed schematic drawings are provided which describe some possible configurations for the various systems.

Rudolph, L. K.; King, D. Q.

1984-01-01

313

Electromagnetic/Electrothermal Gun Technology Development.  

National Technical Information Service (NTIS)

The Army Science Board (ASB) was directed to monitor progress of the electromagnetic/electrothermal gun technology development program. This second and final report fulfills all ASB responsibilities indicated in the Congressional directives and the Panel ...

A. F. Grum A. R Eaton G. A. Thiele M. C. Gourdine P. J. Weinberger

1990-01-01

314

Sketches of the history of Electromagnetics  

NSDL National Science Digital Library

This website outlines the history of light, electricity, magnetism and electromagnetic theory, placed in a linked timeline order with corresponding biographical sketches. It includes events from antiquity to 1933.

Biggus, Jeff

1996-01-01

315

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

316

Progress In Electromagnetics Research Symposium (PIERS)  

NASA Technical Reports Server (NTRS)

The third Progress In Electromagnetics Research Symposium (PIERS) was held 12-16 Jul. 1993, at the Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California. More than 800 presentations were made, and those abstracts are included in this publication.

1993-01-01

317

Injection Molding Compound for Electromagnetic Shielding.  

National Technical Information Service (NTIS)

A thermoplastic injection molding compound with excellent electromagnetic shielding effectiveness has been developed as a material for housings of electronic equipment. The compound contains stainless steel fiber as an electroconductive filler and maintai...

H. Takahama H. Tamaki T. Herai

1988-01-01

318

Electromagnetic strangeness production and hadronic form factors.  

National Technical Information Service (NTIS)

Using a phenomenological approach based on an isobaric model including s, u, and t-channels, a thorough study of the associated strangeness electromagnetic production has been performed. The sensitivity to the hadronic form factors of the reactions ep (yi...

C. Charles J. C. David M. Guidal B. Saghai C. Fayard

1995-01-01

319

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

320

Electromagnetic Treatment of Loblolly Pine Seeds.  

National Technical Information Service (NTIS)

Loblolly pine (Pinus taeda L.) seeds were exposed to an electromagnetic radiation treatment (Energy Transfer Process, marketed by the Energy Transfer Corporation), and the effects of the treatments on seed germination, seedling development, disease resist...

J. P. Barnett S. L. Krugman

1989-01-01

321

Stochastic quantization of the electromagnetic field  

Microsoft Academic Search

Stochastic field equations for electromagnetism are presented. The covariance in the ground state is calculated. The question of Lorentz covariance is examined. The connection with ordinary quantum field theory is made. The theory is compared with stochastic electrodynamics.

Mark Davidson

1981-01-01

322

Electromagnetic responses of magnetic conductive hollow fibers  

NASA Astrophysics Data System (ADS)

Electromagnetic parameters for a magnetic conductive hallow fiber have been derived, and the anisotropy of the magnetic permeability and the electric permittivity for a hollow fiber was demonstrated theoretically. The axial parameters ?// and ?// are the key factors related to electromagnetic characteristics of the hollow fiber. Simulations have been carried out to study the axial permeability ?//, and axial permittivity ?// of a magnetic conductive hallow fiber with different geometric, and electrical parameters such as diameter, aspect ratio and conductivity The simulations carried out reveal several interesting properties of the hallow fiber's electromagnetic parameters. (1) The parameters ?'//, ?''//, ?'// and ?''// all decrease with increasing outer radius from 0.5 to 6 µm. (2) When the aspect ratio of the hallow fiber is above 30 µm, ?'// and ?''// remain at constant, while, ?'// and ?''// are found to increase. (3) The parameters ?'//, ?''//, and ?'// all decrease with increasing conductivity, however ?''// increases with increasing conductivity. Additionally these simulated results are consistent with reported experimental results carried out on electromagnetically modified hollow carbon fibers.

Deng, Lianwen; Luo, Heng; Huang, Shengxiang; Zhou, Liang; Hu, Zhaowen; Zhou, Kesheng; Xiao, Peng

2012-04-01

323

Development of an Electromagnetic Pellet-Accelerator.  

National Technical Information Service (NTIS)

A simple electromagnetic accelerator was developed and tested. The primary and secondary circuits (the driver) were investigated analytically and experimentally. Optimum values and configuration for the primary and secondary coils were derived in a model....

E. Igenbergs H. Kuczera P. Lell

1979-01-01

324

Some Student Conceptions of Electromagnetic Induction  

NASA Astrophysics Data System (ADS)

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

Thong, Wai Meng; Gunstone, Richard

2008-01-01

325

Multiplexers for Multifunction Electromagnetic Radiating Systems (MERS).  

National Technical Information Service (NTIS)

The Multiplexers for Multifunction Electromagnetic Radiating Systems (MERS) objective was to merge four different radio frequency (RF) sensor systems into a single-antenna structure. Currently, the four candidates are Combat Direction Finding (CDF), Ident...

W. Henry T. Q. Ho M. Mills D. Rubin

1995-01-01

326

Electromagnetic Launchers: Background and the MRL Program.  

National Technical Information Service (NTIS)

An active R. & D. program is being undertaken into the technology of electromagnetic launchers. These have potential applications in weaponry, controlled thermonuclear fusion, space launch, advanced industrial processes, equation-of-state research, genera...

Y. C. Thio

1982-01-01

327

Galium Electromagnetic (GEM) Thruster Concept and Design  

NASA Technical Reports Server (NTRS)

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 first stage through a porous metal electrode using an electromagnetic pump. At a designated time, a pulsed discharge (approx. 10-50 J) is initiated in the first stage, ablating the liquid gallium from the porous electrode surface and ejecting a dense thermal gallium plasma into the second state. The presence of the gallium plasma in the second stage serves to trigger the high-energy (approx. 500 J), second-stage pulse which provides the primary electromagnetic (j x B) acceleration.

Polzin, Kurt A.; Markusic, Thomas E.

2005-01-01

328

Electromagnetic damping of neutron star oscillations  

NASA Technical Reports Server (NTRS)

A simple model of magnetic field perturbations driven by neutron star oscillations is used to estimate the electromagnetic power radiated by g-modes and torsional oscillations. The calculation assumes that the neutron star has a frozen-in magnetic field which is perturbed by the oscillatory motions of the surface. The disturbances propagate into the vacuum as outgoing electromagnetic waves. The relative effectiveness of Joule heating of the neutron star crust by pulsation-induced electric currents is estimated. It is concluded that electromagnetic damping is the dominant energy dissipation mechanism for quadrupole g-mode oscillations of neutron stars. For dipole spheroidal modes, both electromagnetic radiation and Joule heating are important, and there is no gravitational radiation emitted by these modes.

Mcdermott, P. N.; Savedoff, M. P.; Van Horn, H. M.; Zweibel, E. G.; Hansen, C. J.

1984-01-01

329

Naval Electromagnetic (EM) Gun Technology Assessment.  

National Technical Information Service (NTIS)

The Naval Research Advisory Committee was asked in May 2003 to conduct an assessment of the current maturity of electromagnetic (EM) gun technology for the Assistant Secretary of the Navy (Research, Development & Acquisition). Specifically, the Committee ...

J. Bachkosky D. Katz R. Rumpf W. Weldon

2003-01-01

330

Naval Electromagnetic (EM) Gun Technology Assessment.  

National Technical Information Service (NTIS)

The Naval Research Advisory Committee was asked in May 2003 to conduct an assessment of the current maturity of electromagnetic (EM) gun technology for the Assistant Secretary of the Navy (Research, Development & Acquisition). Specifically, the Commit...

J. Bachkosky D. Katz R. Rumpf W. Weldon

2004-01-01

331

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

332

Serpentine Robot Arm Contains Electromagnetic Actuators  

NASA Technical Reports Server (NTRS)

Identical modules assembled into flexible robot arm configured in serpentlike fashion to manipulate objects while avoiding obstacles. Each module includes integral electromagnetic actuators energized selectively to produce variety of motions, stationary configurations, and combinations thereof.

Moya, Israel A.; Studer, Philip A.

1994-01-01

333

Experimental Study on Electromagnetically Driven Shock Tube.  

National Technical Information Service (NTIS)

In this paper the criteria followed in the construction of an electromagnetic shock tube with internal electrodes are described. The purpose of this work is to allow the investigation on phenomena accompanying a shock wave, being generated by abruptly dis...

C. Bistagnino

1968-01-01

334

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

335

Electromagnetic coupling through multiconductor cable shields  

SciTech Connect

This paper discusses two approaches to the determination of the distribution of source terms of a shielded multiconductor cable due to electromagnetic coupling through the shield. Comparisons are made of the results of some of these calculations with available data.

Tigner, T.E.; Frederick, D.; Setty, P.N.; Sutton, R.W.

1982-12-01

336

Tour of the Electromagnetic Spectrum Book  

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.

337

Electromagnetism in Interaction with Deformable Solids.  

National Technical Information Service (NTIS)

This is the final report on research begun. The research effort encompasses three subject areas consisting of the following: (1) Electromagnetism in interaction with conducting and nonconducting polarizable and magnetizable deformable solid continua; (2) ...

H. F. Tiersten

1981-01-01

338

Introduction to the Electromagnetism of the Sea.  

National Technical Information Service (NTIS)

The factors which influence the propagation of electromagnetic waves through the ocean and through the air-ocean interface are discussed in detail including numerical data. The effects include refraction, absorption, reflection. The entire frequency range...

P. Halley

1974-01-01

339

Generalization of the Electromagnetic Current Operator.  

National Technical Information Service (NTIS)

The present experimental data for the radiative decays of vector mesons require a generalization of the Gell-Mann-Nishijima formula for the electromagnetic current. This generalization will affect the values of the magnetic moments but not the charges. (E...

A. Bohm

1977-01-01

340

Electromagnetic Teeming and Treatment of Liquid Metal.  

National Technical Information Service (NTIS)

The report deals with application of an electromagnetic field to control the teeming of liquid metal in casting and metallurgical operations, and the development of new processes of liquid metal treatment and its purification from gases, nonmetallic inclu...

L. A. Verte

1972-01-01

341

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

342

Moto Kanda and I on electromagnetic sensors  

Microsoft Academic Search

This paper summarizes, with a short bibliography of major references, the work of Dr. Motohisa (Moto) Kanda and Carl Baum on electromagnetic sensors. This topic of common interest was the subject of many of our discussions over the years

C. E. Baum

2002-01-01

343

Electromagnetic radiation from beam-plasma instabilities  

NASA Technical Reports Server (NTRS)

The mechanism by which unstable electrostatic waves of an electron-beam plasma system are converted into observed electromagnetic waves is of great current interest in space plasma physics. Electromagnetic radiation arises from both natural beam-plasma systems, e.g., type III solar bursts and kilometric radiation, and from man-made electron beams injected from rockets and spacecraft. In the present investigation the diagnostic difficulties encountered in space plasmas are overcome by using a large laboratory plasma. A finite diameter (d approximately equal to 0.8 cm) electron beam is injected into a uniform quiescent magnetized afterglow plasma of dimensions large compared with electromagnetic wavelength. Electrostatic waves grow, saturate and decay within the uniform central region of the plasma volume so that linear mode conversion on density gradients can be excluded as a possible generation mechanism for electromagnetic waves.

Stenzel, R. L.; Whelan, D. A.

1982-01-01

344

Method and apparatus for measuring electromagnetic radiation  

NASA Technical Reports Server (NTRS)

An apparatus and method are described in which the capacitance of a semiconductor junction subjected to an electromagnetic radiation field is utilized to indicate the intensity or strength of the radiation.

Been, J. F. (inventor)

1973-01-01

345

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

346

High-Power Electromagnetic Thruster Being Developed  

NASA Technical Reports Server (NTRS)

High-power electromagnetic thrusters have been proposed as primary in-space propulsion options for several bold new interplanetary and deep-space missions. As the lead center for electric propulsion, the NASA Glenn Research Center designs, develops, and tests high-power electromagnetic technologies to meet these demanding mission requirements. Two high-power thruster concepts currently under investigation by Glenn are the magnetoplasmadynamic (MPD) thruster and the Pulsed Inductive Thruster (PIT).

LaPointe, Michael R.; Mikellides, Pavlos G.

2001-01-01

347

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

348

Low-Frequency Electromagnetic Backscattering from Tunnels  

SciTech Connect

Low-frequency electromagnetic scattering from one or more tunnels in a lossy dielectric half-space is considered. The tunnel radii are assumed small compared to the wavelength of the electromagnetic field in the surrounding medium; a tunnel can thus be modeled as a thin scatterer, described by an equivalent impedance per unit length. We examine the normalized backscattering width for cases in which the air-ground interface is either smooth or rough.

Casey, K; Pao, H

2007-01-16

349

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

350

Measurements in an electromagnetic test laboratory  

NASA Astrophysics Data System (ADS)

Electromagnetic compatibility test equipment and the specially built strong electromagnetic pulses immunity test system, developed in order to control the characteristics of aerospace communication systems, are described. The compatability tests are carried out at frequencies from 10KHz to 10GHz in a Faraday cage. Measurement is implemented with an optical transmission bus. The extremely high voltage pulse generator assembled for immunity testing is based on Marx generators. Measurement and command are made via optical circuits.

Raveu, Bernard

1987-01-01

351

Channel shape optimization of electromagnetic pumps  

SciTech Connect

Electromagnetic pumps are used for the transportation of liquid metals such as the cooling sodium of fast breeder nuclear reactors. The design of this induction machine is close to that of a tubular linear induction motor. In this paper, channels of variable cross section are used to improve the efficiency of electromagnetic pumps. The optimum channel shape is derived analytically and is then tested with a finite element code. The performances are compared with those of standard pumps.

Leboucher, L.; Boissonneau, P. [LEGI, Genoble (France). Inst. de Mecanique de Grenoble] [LEGI, Genoble (France). Inst. de Mecanique de Grenoble; Villani, D. [Framatome direction Novatome, Lyon (France)] [Framatome direction Novatome, Lyon (France)

1995-05-01

352

Slot design of optimized electromagnetic pump  

SciTech Connect

Electromagnetic pumps are used for the transportation of liquid metals such as the cooling sodium of fast breeder nuclear reactors. The design of this induction machine is close to that of a tubular linear induction motor. A non uniform slot distribution is used to optimize electromagnetic pumps. This geometry is tested with a finite element code. The performances are compared with the regular slot distribution of Industrial prototypes.

Leboucher, L. (LEGI, Grenoble (France). Institut de Mecanique); Villani, D. (Framatome direction Novatome, Lyon (France))

1993-11-01

353

Generating highly uniform electromagnetic field characteristics  

DOEpatents

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

Crow, James Terry (Albuquerque, NM)

1998-01-01

354

Generating highly uniform electromagnetic field characteristics  

DOEpatents

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

Crow, J.T.

1997-06-24

355

Generating highly uniform electromagnetic field characteristics  

DOEpatents

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

Crow, James T. (Albuquerque, NM)

1998-01-01

356

Generating highly uniform electromagnetic field characteristics  

DOEpatents

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

Crow, James T. (Albuquerque, NM)

1997-01-01

357

Generating highly uniform electromagnetic field characteristics  

DOEpatents

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

Crow, J.T.

1998-02-10

358

Generating highly uniform electromagnetic field characteristics  

DOEpatents

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

Crow, J.T.

1998-05-05

359

Apparatus and Methods for Mitigating Electromagnetic Emissions  

NASA Technical Reports Server (NTRS)

Apparatus, methods, and other embodiments associated with mitigation of magnetic fields are described herein. In an embodiment, a method for mitigating an electromagnetic field includes positioning a mitigating coil around a linear alternator of linear motor so that the mitigating coil is coaxially located with an alternator coil; arranging the mitigating coil to generate a field to mitigate an electromagnetic field generated by the alternator coil; and passing an induced current from the alternator coil through the mitigating coil.

Geng, Steven M. (Inventor); Niedra, Janis M. (Inventor)

2013-01-01

360

Parallel computation of electromagnetic fields  

SciTech Connect

The DSI3D code is designed to numerically solve electromagnetics problems involving complex objects by solving Maxwell`s curl equations in the time-domain and in three space dimensions. The code has been designed to run on the new parallel processing computers as well as on conventional serial computers. The DSI3D code is unique for the following reasons: It runs efficiently on a variety of parallel computers, Allows the use of unstructured non-orthogonal grids, Allows a variety of cell or element types, Reduces to be the Finite Difference Time Domain (FDID) method when orthogonal grids are used, Preserves charge or divergence locally (and globally), Is non- dissipative, and Is accurate for non-orthogonal grids. This method is derived using a Discrete Surface Integration (DSI) technique. As formulated, the DSI technique can be used with essentially arbitrary unstructured grids composed of convex polyhedral cells. This implementation of the DSI algorithm allows the use of unstructured grids that are composed of combinations of non-orthogonal hexahedrons, tetrahedrons, triangular prisms and pyramids. This algorithm reduces to the conventional FDTD method when applied on a structured orthogonal hexahedral grid.

Madsen, N.K.

1997-05-21

361

Nde: Surfing the Electromagnetic Spectrum  

NASA Astrophysics Data System (ADS)

Advances in Nondestructive Evaluation demand an arsenal of techniques. This was as true twenty years ago as it is today. As materials and their associated technologies progress, so must the strategy for evaluating the quality of the product. Nondestructive Evaluation is a constant struggle to extract, from classical and quantum physics, the quintessential elements that will optimally address an inspection requirement, apart from purely academic interest. It must work to be useful and thereby advance the field. The electromagnetic spectrum, from Roentgen to Maxwell/Hertz, lies at the foundation of both classical and quantum physics. Not only has NDE plucked pearls form every nook of the spectrum ranging from X-rays to T-rays but also has managed to utilize virtually every known coupling of the spectrum to the classical mechanics of heat and sound. I will ``surf'' the spectrum to provide a sampling of what NDE has extracted past and present as well as try to couple to its future.

Ringermacher, Harry I.

2010-02-01

362

Electromagnetic fields in cased borehole  

SciTech Connect

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

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

2001-07-20

363

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

364

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

365

Electromagnetic launch of lunar material  

NASA Technical Reports Server (NTRS)

Lunar soil can become a source of relatively inexpensive oxygen propellant for vehicles going from low Earth orbit (LEO) to geosynchronous Earth orbit (GEO) and beyond. This lunar oxygen could replace the oxygen propellant that, in current plans for these missions, is launched from the Earth's surface and amounts to approximately 75 percent of the total mass. The reason for considering the use of oxygen produced on the Moon is that the cost for the energy needed to transport things from the lunar surface to LEO is approximately 5 percent the cost from the surface of the Earth to LEO. Electromagnetic launchers, in particular the superconducting quenchgun, provide a method of getting this lunar oxygen off the lunar surface at minimal cost. This cost savings comes from the fact that the superconducting quenchgun gets its launch energy from locally supplied, solar- or nuclear-generated electrical power. We present a preliminary design to show the main features and components of a lunar-based superconducting quenchgun for use in launching 1-ton containers of liquid oxygen, one every 2 hours. At this rate, nearly 4400 tons of liquid oxygen would be launched into low lunar orbit in a year.

Snow, William R.; Kolm, Henry H.

1992-01-01

366

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

367

Electromagnetic fields stress living cells.  

PubMed

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 and refold damaged proteins and transport them across cell membranes. Induction of the stress response involves activation of DNA, and despite the large difference in energy between ELF and RF, the same cellular pathways respond in both frequency ranges. Specific DNA sequences on the promoter of the HSP70 stress gene are responsive to EMF, and studies with model biochemical systems suggest that EMF could interact directly with electrons in DNA. While low energy EMF interacts with DNA to induce the stress response, increasing EMF energy in the RF range can lead to breaks in DNA strands. It is clear that in order to protect living cells, EMF safety limits must be changed from the current thermal standard, based on energy, to one based on biological responses that occur long before the threshold for thermal changes. PMID:19268550

Blank, Martin; Goodman, Reba

2009-08-01

368

Terahertz electromagnetic response for metamaterial  

NASA Astrophysics Data System (ADS)

Recently, more and more groups are concentrating on learning surface plasma on metal split with sub-wavelength of terahertz. There is a new material which is made of two materials named metamaterial. It is combined with semiconductor and metal materials. Metal parts are made with subwavelength microstructure. Abnormal phenomenon occurred when it is excited by an intense light, showing an enhancement transmission of terahertz wave. In this paper, we design a planar structure composed of gallium arsenide (substrate) and copper (metal). Copper array is plating on a GaAs wafer on order of micron with photoetching technology. The thickness of GaAs and copper layer are 650 and 0.5 micros individually. THz incidence has an enhanced transmission like surface plasmonic resonance with terahertz time-domain system when another exciting lighted on, which made current carriers in photoconductor. This resonance arises from an inductor-capacitor circuit resonance. Comparison is performed between results with and without excitation. The angle of sample plane with terahertz polarization and incidence can affect this electromagnetic response in some degree. Its transmittance with back-incidence is much stronger than that with front-incidence at certain frequencies. This kind of artificial structure has potential abilities in terahertz devices in the future. It is helpful to develop terahertz filter, polarizing film, beam reflector, phase retarder and so on.

Jiang, Xue; Yan, Ziyu; Jin, Bin; Wang, Yu; Mu, Kaijun; Zhou, Qingli; Zhang, Cunlin

2008-03-01

369

Aircraft Lightning Electromagnetic Environment Measurement  

NASA Technical Reports Server (NTRS)

This paper outlines a NASA project plan for demonstrating a prototype lightning strike measurement system that is suitable for installation onto research aircraft that already operate in thunderstorms. This work builds upon past data from the NASA F106, FAA CV-580, and Transall C-180 flight projects, SAE ARP5412, and the European ILDAS Program. The primary focus is to capture airframe current waveforms during attachment, but may also consider pre and post-attachment current, electric field, and radiated field phenomena. New sensor technologies are being developed for this system, including a fiber-optic Faraday polarization sensor that measures lightning current waveforms from DC to over several Megahertz, and has dynamic range covering hundreds-of-volts to tens-of-thousands-of-volts. A study of the electromagnetic emission spectrum of lightning (including radio wave, microwave, optical, X-Rays and Gamma-Rays), and a compilation of aircraft transfer-function data (including composite aircraft) are included, to aid in the development of other new lightning environment sensors, their placement on-board research aircraft, and triggering of the onboard instrumentation system. The instrumentation system will leverage recent advances in high-speed, high dynamic range, deep memory data acquisition equipment, and fiber-optic interconnect.

Ely, Jay J.; Nguyen, Truong X.; Szatkowski, George N.

2011-01-01

370

ALICE electromagnetic calorimeter prototype test  

SciTech Connect

This Memorandum of Understanding between the Test Beam collaborators and Fermilab is for the use of beam time at Fermilab during the Fall, 2005 Meson Test Beam Run. The experimenters plan to measure the energy, position, and time resolution of prototype modules of a large electromagnetic calorimeter proposed to be installed in the ALICE experiment at the LHC. The ALICE experiment is one of the three large approved LHC experiments, with ALICE placing special emphasis on the LHC heavy-ion program. The large electromagnetic calorimeter (EMCal) is a US initiative that is endorsed by the ALICE collaboration and is currently in the early stages of review by the Nuclear Physics Division of the DOE. The installation in the test beam at FNAL and test beam measurements will be carried out by the US members of the ALICE collaboration (ALICE-USA). The overall design of the ALICE EMCal is heavily influenced by its location within the ALICE L3 magnet. The EMCal is to be located inside the large room temperature magnet within a cylindrical integration volume approximately l12cm deep, by 5.6m in length, sandwiched between the ALICE TPC space frame and the L3 magnet coils. The chosen technology is a layered Pb-scintillator sampling calorimeter with a longitudinal pitch of 1.6mm Pb and 1.6mm scintillator. The full detector spans {eta} = -0.7 to {eta} = 0.7 with an azimuthal acceptance of {Delta}{phi} = 120{sup o}. The EMCal readout is of a ''Shish-Kabob'' type similar to the PHENIX Pb-scintillator sampling calorimeter in which the scintillation light is collected via wavelength shifting fibers running through the Pb-scintillator tiles perpendicular to the front surface. The detector is segmented into {approx}14000 towers. The basic structural units of the calorimeter are supermodules, each subtending approximately {approx}20{sup o} in {Delta}{phi} and 0.7 units in {Delta}{eta}. Supermodules are assembled from individual modules. The modules are further segmented into 2 x 2 individually read out towers. The fibers from an individual tower are grouped together to form readout tower bundles. These are each optically coupled to an avalanche photodiode (APO) via a short light guide to provide some spatial optical mixing and to match the fiber bundle to the APO. The module assembly is indicated in Figure l. The supermodules weigh about 9.6 tons and are the basic units handled during installation. Each supermodule is roughly I45cm wide at the front surface by 350cm long with an active depth of 24.5cm (at {eta} = 0) plus an additional 6.6 cm of depth in structural plates. The physical characteristics of the ALICE EMCal are summarized in Table 1. The EMCal test beam measurements at FNAL will utilize a stacked 4 x 4 array of prototype EMCal modules (8 x 8 towers). All towers will be instrumented with the same model APO and preamplifier as will be used in the ALICE experiment and all channels will be readout with existing prototype front end electronics intended for use in ALICE. The goals of the test beam measurements are: To investigate the energy resolution, linearity, uniformity, and position resolution, using electron beams; To study the energy dependence of the response to electrons and hadrons to determine the particle identification capabilities of the EMCal by shower shape; And to investigate the timing characteristics of the energy signal for crude time-of-flight measurement ({approx} 1ns) for use for anti-neutron rejection. Measurements will be made for comparison with different signal shaping times in the front end electronics.

Awes, Terry; /Oak Ridge

2005-09-01

371

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

372

[Health effects of electromagnetic fields].  

PubMed

Use of electricity causes extremely low frequency magnetic fields (ELF-MF) and wireless communication devices emit radiofrequency electromagnetic fields (RF-EMF). Average ELF-MF exposure is mainly determined by high voltage power lines and transformers at home or at the workplace, whereas RF-EMF exposure is mainly caused by devices operating close to the body (mainly mobile and cordless phones). Health effects of EMF are controversially discussed. The IARC classified ELF-MF and RF-EMF as possible carcinogenic. Most consistent epidemiological evidence was found for an association between ELF-MF and childhood leukaemia. If causal, 1 - 4 percent of all childhood leukaemia cases could be attributed to ELF-MF. Epidemiological research provided some indications for an association between ELF-MF and Alzheimer's diseases as well as amyotrophic lateral sclerosis, although not entirely consistent. Regarding mobile phones and brain tumours, some studies observed an increased risk after heavy or long term use on the one hand. On the other hand, brain tumour incidence was not found to have increased in the last decade in Sweden, England or the US. Acute effects of RF-EMF on non-specific symptoms of ill health seem unlikely according to randomized and double blind provocation studies. However, epidemiological research on long term effects is still limited. Although from the current state of the scientific knowledge a large individual health risk from RF-EMF exposure is unlikely, even a small risk would have substantial public health relevance because of the widespread use of wireless communication technologies. PMID:24297859

Röösli, Martin

2013-12-01

373

Is Electromagnetic Gravity Control Possible?  

SciTech Connect

We study the interplay of Einstein's Gravitation (GR) and Maxwell's Electromagnetism, where the distribution of energy-momentum is not presently known (The Feynman Lectures, Vol 2, Chapter 27, section 4). As Feynman himself stated, one might in principle use Einstein's equations of GR to find such a distribution. GR (born in 1915) presently uses the Levi-Civita connection, LCC (the LCC was born two years after GR as a new concept, and not just as the pre-existing Christoffel symbols that represent it). Around 1927, Einstein proposed for physics an alternative to the LCC that constitutes a far more sensible and powerful affine enrichment of metric Riemannian geometry. It is called teleparallelism (TP). Its Finslerian version (i.e. in the space-time-velocity arena) permits an unequivocal identification of the EM field as a geometric quantity. This in turn permits one to identify a completely geometric set of Einstein equations from curvature equations. From their right hand side, one may obtain the actual distribution of EM energy-momentum. It is consistent with Maxwell's equations, since these also are implied by the equations of structure of TP. We find that the so-far-unknown terms in this distribution amount to a total differential and do not, therefore, alter the value of the total EM energy-momentum. And yet these extra terms are at macroscopic distances enormously larger than the standard quadratic terms. This allows for the generation of measurable gravitational fields by EM fields. We thus answer affirmatively the question of the title.

Vargas, Jose G. [PST Associates, 600 Westover Rd, Columbia, SC 29210 (United States); Torr, Douglas G. [PST Associates, 5221 Tern Place, Fayetteville, NC 28311-1967 (United States)

2004-02-04

374

Relativistic electromagnetic ion cyclotron instabilities.  

PubMed

The relativistic instabilities of electromagnetic ion cyclotron waves driven by MeV ions are analytically and numerically studied. As caused by wave magnetic field and in sharp contrast to the electrostatic case, interesting characteristics such as Alfve nic behavior and instability transition are discovered and illuminated in detail. The instabilities are reactive and are raised from the coupling of slow ions' first-order resonance and fast ions' second-order resonance, that is an essential extra mechanism due to relativistic effect. Because of the wave magnetic field, the nonresonant plasma dielectric is usually negative and large, that affects the instability conditions and scaling laws. A negative harmonic cyclotron frequency mismatch between the fast and slow ions is required for driving a cubic (and a coupled quadratic) instability; the cubic (square) root scaling of the peak growth rate makes the relativistic effect more important than classical mechanism, especially for low fast ion density and Lorentz factor being close to unity. For the cubic instability, there is a threshold (ceiling) on the slow ion temperature and density (the external magnetic field and the fast ion energy); the Alfve n velocity is required to be low. This Alfve nic behavior is interesting in physics and important for its applications. The case of fast protons in thermal deuterons is numerically studied and compared with the analytical results. When the slow ion temperature or density (the external magnetic field or the fast ion energy) is increased (reduced) to about twice (half) the threshold (ceiling), the same growth rate peak transits from the cubic instability to the coupled quadratic instability and a different cubic instability branch appears. The instability transition is an interesting new phenomenon for instability. PMID:15903591

Chen, K R; Huang, R D; Wang, J C; Chen, Y Y

2005-03-01

375

Light transmitting electromagnetic wave shielding composite materials using electromagnetic wave polarizing effect  

NASA Astrophysics Data System (ADS)

Light transmitting and electromagnetic wave shielding material using a cross-polarizing effect of unidirectionally aligned electrically conductive fiber-dielectric composite has been developed. Two-electrically isolated unidirectionally aligned continuous electrically conductive fiber layers were incorporated into an optically transparent polymethylmethacrylate (PMMA) matrix. Electromagnetic wave shielding by the polarizing effect of the composite was examined by the free-space method in a frequency range from 18 to 24 GHz. The composite shields electromagnetic wave with a small expense of light transmittance of the PMMA matrix. Effect of fiber spacing, angle of fiber axis direction, and polarizing mode of incident electromagnetic wave are discussed based on experimental results. It is concluded that the use of the polarizing effect is an effective way to obtain an optically transparent electromagnetic shielding material.

Matumura, K.; Kagawa, Y.; Baba, K.

2007-01-01

376

Power law inflation with electromagnetism  

SciTech Connect

We generalize Ringström’s global future causal stability results (Ringström 2009) [11] for certain expanding cosmological solutions of the Einstein-scalar field equations to solutions of the Einstein–Maxwell-scalar field system. In particular, after noting that the power law inflationary spacetimes (M{sup n+1},g{sup -hat}, ?{sup -hat}) considered by Ringström (2009) in [11] are solutions of the Einstein–Maxwell-scalar field system (with exponential potential) as well as of the Einstein-scalar field system (with the same exponential potential), we consider (nonlinear) perturbations of initial data sets of these spacetimes which include electromagnetic perturbations as well as gravitational and scalar perturbations. We show that if (as in Ringström (2009) [11]) we focus on pairs of relatively scaled open sets U{sub R{sub 0}}?U{sub 4R{sub 0}} on an initial slice of (M{sup n+1},g{sup -hat}), and if we choose a set of perturbed data which on U{sub 4R{sub 0}} is sufficiently close to that of (M{sup n+1},g{sup -hat},?{sup -hat}, A{sup -hat} = 0), then in the maximal globally hyperbolic spacetime development (M{sup n+1},g,?,A) of this data via the Einstein–Maxwell-scalar field equations, all causal geodesics emanating from U{sub R{sub 0}} are future complete (just as in (M{sup n+1},g{sup -hat})). We also verify that, in a certain sense, the future asymptotic behavior of the fields in the spacetime developments of the perturbed data sets does not differ significantly from the future asymptotic behavior of (M{sup n+1},g{sup -hat}, ?{sup -hat}, A{sup -hat} = 0). -- Highlights: •We prove stability of expanding solutions of the Einstein–Maxwell-scalar field equations. •All nearby solutions are geodesically complete. •The topology of the initial slice is irrelevant to our stability results.

Luo, Xianghui; Isenberg, James, E-mail: isenberg@uoregon.edu

2013-07-15

377

Electromagnetics for Detecting Shallow Tunnels  

NASA Astrophysics Data System (ADS)

Detecting tunnels by geophysical means, even very shallow ones, has been difficult, to say the least. Despite heavy R&D funding from the military since the early 70s, geophysicists have not produced tools that are simple and practical enough to meet the military needs. The initial interest and R&D funding on the subject perhaps started with the Vietcong tunnels in the 60s. Tunnels in the Korean DMZ, first found in the mid 70s, sharply escalated the R&D spending. During the 90s, covert tunnels along the US-Mexico border have kept the topic alive but at a minimal funding level. Most recent interest appears to be in the terrorism-related shallow tunnels, more or less anywhere in the regions of conflict. Despite the longstanding effort in the geophysical community under heavy public funding, there is a dearth of success stories where geophysicists can actually claim to have found hitherto unknown tunnels. For instance, geophysics has not discovered a single tunnel in Vietnam or in Korea! All tunnels across the Korean DMZ were found from human intelligence. The same is true to all illicit tunnels found along the southwestern border. The tunnels under discussion are clandestine, which implies that the people who built them do not wish others to succeed in finding them. The place around the tunnel, therefore, may not be the friendliest venue for surveyors to linger around. The situation requires tools that are fast, little noticeable, and hardly intrusive. Many geophysical sensors that require ground contacts, such as geophones and electrodes that are connected by a myriad of cables, may not be ideal in this situation. On the other hand, a sensor that can be carried by vehicle without stopping, and is nothing obviously noticeable to bystanders, could be much more acceptable. Working at unfriendly environment also requires forgoing our usual practices where we collect data leisurely and make pretty maps later. To be useful, geophysical tools must be able to process observed data and translate them into actionable results. They may in forms of audio (similar to the beeper of a landmine detector), strip chart, or even a 2D graphic display on a computer screen. In short, the tool must be able to declare a contact, audibly or graphically, in real time or shortly thereafter. In summary, we have two questions here. The first one is if any of the available geophysical tools can detect tunnels. If the answer is yes, then the next question is if any of them are able to perform fast in an unfriendly environment. Electromagnetic sensors may be able to meet the operational requirements: under what circumstances it can find tunnels would be another outstanding question.

Won, I.

2006-05-01

378

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

379

Broadband electromagnetic cloaking with smart metamaterials.  

PubMed

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. PMID:23169054

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

2012-01-01

380

Advanced electromagnetic methods for aerospace vehicles  

NASA Technical Reports Server (NTRS)

The Advanced Helicopter Electromagnetics (AHE) Industrial Associates Program continues its research on variety of main topics identified and recommended by the Advisory Task Force of the program. The research activities center on issues that advance technology related to helicopter electromagnetics. While most of the topics are a continuation of previous works, special effort has been focused on some of the areas due to recommendations from the last annual conference. The main topics addressed in this report are: composite materials, and antenna technology. The area of composite materials continues getting special attention in this period. The research has focused on: (1) measurements of the electrical properties of low-conductivity materials; (2) modeling of material discontinuity and their effects on the scattering patterns; (3) preliminary analysis on interaction of electromagnetic fields with multi-layered graphite fiberglass plates; and (4) finite difference time domain (FDTD) modeling of fields penetration through composite panels of a helicopter.

Balanis, Constantine A.; Sun, Weimin; El-Sharawy, El-Budawy; Aberle, James T.; Birtcher, Craig R.; Peng, Jian; Tirkas, Panayiotis A.

1992-01-01

381

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

382

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

383

Gallium Electromagnetic (GEM) Thrustor Concept and Design  

NASA Technical Reports Server (NTRS)

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 Fig. 1. In this concept, liquid gallium propellant is pumped into the first stage through a porous metal electrode using an electromagneticpump[l]. At a designated time, a pulsed discharge (approx.10-50 J) is initiated in the first stage, ablating the liquid gallium from the porous electrode surface and ejecting a dense thermal gallium plasma into the second state. The presence of the gallium plasma in the second stage serves to trigger the high-energy (approx.500 I), send-stage puke which provides the primary electromagnetic (j x B) acceleration.

Polzin, Kurt A.; Markusic, Thomas E.

2006-01-01

384

Gravitational sources of purely electromagnetic origin  

NASA Astrophysics Data System (ADS)

The feasibility of developing an equation of state is examined for an electromagnetic mass model which is not under tension. The analysis attempts to dispense with the invariant relation described by Tiwari et al. (1984) in which a repulsive source describes the mass model. By considering the Einstein-Maxwell field equations for charged dust corresponding to an axially symmetric line element of Levi-Civita (1919), it is shown that the compatibility of the charged fluid source and the axially symmetric field exists when the pressure vanishes. The charged dust distributions are first considered to have only electromagnetic origins, and then the distributions are examined in cases where certain conditions are necessary for electromagnetic origins to exist. The solution for the source of the Curzon (1924) particle field, and the exterior field of an electron can be described by the source of the 'Reissner-Nordstrom-Curzon' field.

Tiwari, R. N.; Rao, J. R.; Ray, Saibal

1991-04-01

385

PhET Simulation: Magnets and Electromagnets  

NSDL National Science Digital Library

In this interactive simulation, users explore the interactions between a compass and a bar magnet and investigate characteristics of electromagnets. This resource was developed to help students build a foundation to understand electromagnetism and factors affecting magnetic field strength. It is appropriate for use in middle school and high school, and could also be adapted for use in college physics preparatory courses. This resource is part of the PhET project (Physics Education Technology) a growing collection of simulations and curriculum support for teachers and learners of physics, biology, chemistry, and earth science. See Related Items for a link to a standards-based lesson plan and elicitation questions developed specifically to accompany the "Magnets and Electromagnets" simulation.

2010-12-02

386

Apparatus for processing electromagnetic radiation and method  

NASA Technical Reports Server (NTRS)

Measuring apparatus including a ruled member having alternate transparent and opaque zones. An optical coupler connecting the ruled member with electromagnetic radiation-conversion apparatus. The conversion apparatus may include a photomultiplier and a discriminator. Radiation impinging on the ruled member will, in part, be converted to electrical pulses which correspond to the intensity of the radiation. A method of processing electromagnetic radiation includes providing a member having alternating dark and light zones, establishing movement of the member through the beam of electromagnetic radiation with the dark zones interrupting passage of radiation through the rule, providing an optical coupler to connect a portion of the radiation with a conversion station where the radiation portion is converted into an electrical pulse which is related to the intensity of the radiation received at the conversion station. The electrical pulses may be counted and the digitized signals stored or permanently recorded to produce positional information.

Gatewood, George D. (Inventor)

1983-01-01

387

Electromagnetic properties for arbitrary spin particles: Natural electromagnetic moments from light-cone arguments  

SciTech Connect

We revisit the old-standing problem of the electromagnetic interaction for particles of arbitrary spin. Based on the assumption that light-cone helicity at tree level and Q{sup 2}=0 should be conserved nontrivially by the electromagnetic interaction, we are able to derive all the natural electromagnetic moments for a pointlike particle of any spin. We provide here a transparent decomposition of the electromagnetic current in terms of covariant vertex functions. We also define in a general way the electromagnetic multipole form factors, and show their relation with the electromagnetic moments and covariant vertex functions. The light-cone helicity conservation argument determines uniquely the values of all electromagnetic moments, which we refer to as the 'natural' ones. These specific values are in accordance with the standard model, and the prediction of universal g=2 gyromagnetic factor is naturally recovered. We provide a very simple and compact formula for these natural moments. As an application of our results, we generalize the discussion of quark transverse charge densities to particles with arbitrary spin, giving more physical support to the light-cone helicity conservation argument.

Lorce, Cedric [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet, D-55099 Mainz (Germany)

2009-06-01

388

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

389

Electromagnetic wave collapse in a radiation background.  

PubMed

The nonlinear interaction, due to quantum electrodynamical (QED) effects between an electromagnetic pulse and a radiation background, is investigated by combining the methods of radiation hydrodynamics with the QED theory for photon-photon scattering. For the case of a single coherent electromagnetic pulse, we obtain a Zakharov-like system, where the radiation pressure of the pulse acts as a driver of acoustic waves in the photon gas. For a sufficiently intense pulse and/or background energy density, there is focusing and the subsequent collapse of the pulse. The relevance of our results for various astrophysical applications are discussed. PMID:14611403

Marklund, Mattias; Brodin, Gert; Stenflo, Lennart

2003-10-17

390

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

391

Electromagnetic effects on toroidal momentum transport  

NASA Astrophysics Data System (ADS)

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.

2010-12-01

392

Optimization design of electromagnetic shielding composites  

NASA Astrophysics Data System (ADS)

The effective electromagnetic parameters physical model of composites and prediction formulas of composites' shielding effectiveness and reflectivity were derived based on micromechanics, variational principle and electromagnetic wave transmission theory. The multi-objective optimization design of multilayer composites was carried out using genetic algorithm. The optimized results indicate that material parameter proportioning of biggest absorption ability can be acquired under the condition of the minimum shielding effectiveness can be satisfied in certain frequency band. The validity of optimization design model was verified and the scheme has certain theoretical value and directive significance to the design of high efficiency shielding composites.

Qu, Zhaoming; Wang, Qingguo; Qin, Siliang; Hu, Xiaofeng

2013-03-01

393

Simulation of electromagnetic aspects of lightning  

NASA Technical Reports Server (NTRS)

Electromagnetic processes peculiar to the direct-strike case are reviewed with respect to their implications for lightning electromagnetic simulation. At low frequencies (quasistatic) there are important surface-charge-density and corona effects in addition to the surface-current-density effects. At resonant frequencies the frequency-spectral content of the excitation and properties of the arc (attachment, detachment, time history, spatial distribution, resistance, etc.) are significant. Of great complexity in all this are nonlinear aspects of the arc and corona around the system of interest. The complexity of these various processes requires rigor in the simulator design. Potential simulation concepts are presented and their relative merits are discussed.

Baum, C. E.

1980-01-01

394

Device and method for redirecting electromagnetic signals  

DOEpatents

A device fabricated to redirect electromagnetic signals, the device including a primary driver adapted to provide a predetermined force, a linkage system coupled to the primary driver, a pusher rod rotationally coupled to the linkage system, a flexible rod element attached to the pusher rod and adapted to buckle upon the application of the predetermined force, and a mirror structure attached to the flexible rod element at one end and to the substrate at another end. When the predetermined force buckles the flexible rod element, the mirror structure and the flexible rod element both move to thereby allow a remotely-located electromagnetic signal directed towards the device to be redirected.

Garcia, Ernest J. (823 Piedra Larga, NE., Albuquerque, NM 87123)

1999-01-01

395

Electromagnetic continuous casting project: Final report  

SciTech Connect

This report describes the work on development of an electromagnetic casting process for steel, which was carried out at Argonne National Laboratory between January 1985 and December 1987. This effort was concerned principally with analysis and design work on magnet technology, liquid metal feed system, coolant system, and sensors and process controllers. Experimentation primarily involved (1) electromagnetic studies to determine the conditions and controlling parameters for stable levitation and (2) feed-system studies to establish important parameters that control and influence fluid flow from the liquid metal source to the caster. 73 refs., 91 figs., 11 tabs.

Battles, J.E.; Rote, D.M.; Misra, B.; Praeg, W.F.; Hull, J.R.; Turner, L.R.; Shah, V.L.; Lari, R.J.; Gopalsami, N.; Wiencek, T.

1988-10-01

396

LEM-electromagnetic fields measurement laboratory  

NASA Astrophysics Data System (ADS)

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

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

2000-04-01

397

Program For Displaying Computed Electromagnetic Fields  

NASA Technical Reports Server (NTRS)

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

Hom, Kam W.

1995-01-01

398

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

399

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

400

Bell-Szekeres Solution for Colliding Electromagnetic Waves.  

National Technical Information Service (NTIS)

The Bell-Szekeres solution, which describes the collision of plane electromagnetic waves, is considered. The solution is adapted to cases in which the approaching electromagnetic waves are of a specified finite duration, and the polarization of the approa...

J. B. Griffiths

1984-01-01

401

Nonlinear Motion of Plasmas in a Strong Electromagnetic Field.  

National Technical Information Service (NTIS)

A plasma subjected to a strong electromagnetic field with a finite wavelength is considered and a method of obtaining the nonlinear plasma current in all orders of this field presented; both electrostatic and electromagnetic perturbations are considered. ...

N. Thehung

1975-01-01

402

Investigation of Elliptical Cooling Channels for a Naval Electromagnetic Railgun.  

National Technical Information Service (NTIS)

The future Naval Electromagnetic Railgun will use a mega-ampere electrical current to generate an electromagnetic force which accelerates a projectile to hypersonic velocities. The applied current can raise the bulk temperature of the rails by over 100 de...

E. R. Kealey

2005-01-01

403

An overview of electromagnetic interference problems in spacecraft  

NASA Technical Reports Server (NTRS)

Electromagnetic Interference Workshop held at JPL /Feb., 1968/ permitted an exchange of information on electromagnetic interference problems encountered in aerospace programs. The experiences related at this workshop dealt primarily with Surveyor, Lunar Orbiter, OGO, ATS, and Mariner unmanned programs.

Bastow, J. G.

1969-01-01

404

Notebook on Electromagnetic Properties of Composite Materials Below 1 GHz.  

National Technical Information Service (NTIS)

This report is the seventh in a series of reports on the electromagnetic properties of composites materials. The report quantitatively delineates: the vast differences in electromagnetic behavior exhibited by the principle composite materials (Graphite/ep...

D. R. Pflug J. A. Birken R. A. Wallenberg D. T. Auckland

1981-01-01

405

Effects of Nuclear Electromagnetic Pulse (EMP) on Nuclear Power Plants.  

National Technical Information Service (NTIS)

The electromagnetic pulse (EMP) from a high-altitude nuclear detonation consists of a transient pulse of high intensity electromagnetic fields. These intense fields induce current and voltage transients in electrical conductors. Although most nuclear powe...

P. R. Barnes R. R. Davis R. W. Manweiler

1977-01-01

406

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

407

Fermion helicity flip in higher-derivative electromagnetism.  

National Technical Information Service (NTIS)

It is shown that massive fermions have their helicity flipped on account of their interaction with an electromagnetic field described by Podolsky's generalized electrodynamics. Massless fermions, in turn, seem to be unaffected by the electromagnetic field...

A. J. Accioly H. Mukai

1996-01-01

408

Heavy metal exposure in patients suffering from electromagnetic hypersensitivity  

Microsoft Academic Search

BackgroundRisks from electromagnetic devices are of considerable concern. Electrohypersensitive (EHS) persons attribute a variety of rather unspecific symptoms to the exposure to electromagnetic fields. The pathophysiology of EHS is unknown and therapy remains a challenge.

David Ghezel-Ahmadi; Alice Engel; Jörg Weidemann; Lygia Therese Budnik; Xaver Baur; Ulrich Frick; Simone Hauser; Norbert Dahmen

2010-01-01

409

Nuclear electromagnetic pulse and the electric power system  

Microsoft Academic Search

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 electromagnetic pulse (HEMP). Later-time, low frequency fields have been defined as magnetohydrodynamic-electromagnetic pulse (MHD-EMP). Nuclear detonations at, or near the surface of the earth can also produce

J. R. Legro; T. J. Reed

1985-01-01

410

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

411

Advances in Electromagnetic Launch Science and Technology and its Applications  

Microsoft Academic Search

The US 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 stress, 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

2008-01-01

412

Determining and controlling the electromagnetic environment for Space Station Freedom  

NASA Technical Reports Server (NTRS)

Critical issues facing the SSF electromagnetic compatibility community are discussed focusing on effective utilization of SSF resources to perform overall SSF verification. Attention is also given to management and phases of an Electromagnetic Environment Effects Control Program (EEECP) aimed at producing an electromagnetically compatible station.

Pearson, S. D.; Mccollum, M. B.

1993-01-01

413

Psychological Effects of Occupational Exposure to Electromagnetic Fields  

Microsoft Academic Search

Background: In psychological studies, exposure to electromagnetic field is one of the hazardous factors, which has adverse effects on mental health. Exposure to electromagnetic field due to daily use of electricity makes this study so important. The goal of this study was to determine the relationship between psychologi- cal symptoms and occupational exposure to electromagnetic field among workers at High

Yousefi HA; Nasiri P

414

The effect of electromagnetic fields on oxidative DNA damage  

Microsoft Academic Search

Many recent studies have focused on the investigation of the biological effects of electromagnetic field. Although the several types of biological effects of electromagnetic fields have been shown, the molecular mechanisms of these effects have not been explained yet. Some epidemiological studies have suggested that exposure to ambient, low- level 50-60 Hz electromagnetic fields increase risk of disease including cancer

415

Simulation by FEM of sheet metal electromagnetic forming processes  

Microsoft Academic Search

The electromagnetic forming is a process to manufacture a part from sheet metal. The final shape of the part depends on the geometry of the dies, the material behaviour of the workpiece and the process parameters. This paper describes magnetic field transient analysis into electromagnetic forming devices using the finite element method (FEM). The electromagnetic force which causes plastic deformation

Dorin Luca

2009-01-01

416

2-D FEM simulation of an electromagnetic flowmeter  

Microsoft Academic Search

A computational investigation was carried out in a contactless electromagnetic induction flowmeter to measure the velocity of molten aluminum flowing though a ceramic duct. This paper includes the simulation and the experimental validation using as a reference the electromagnetic induction flowmeter and the experimental test. The results make it possible to demonstrate the reliability of the simulation of the electromagnetic

M. A. Rodriguez; D. Morinigo; J. Fernandez; R. Cuesta; J. A. Maroto

2008-01-01

417

ELEMENT-FREE GALERKIN METHOD IN ELECTROMAGNETIC FIELD COMPUTATION  

Microsoft Academic Search

Element-free Galerkin Method (EFGM) as a widely used method in all mesh- less studies has developed extensively in the past twenty years. As an attempt to solve electromagnetic field problems by the meshless method, we study the algorithm and pro- gramming when solving electromagnetic problems by using EFGM. Current research on this method is still in its infancy in electromagnetic

Yun Zhai; Maohui Xia; Lechun Liu

2008-01-01

418

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

419

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

420

Genetic algorithm optimization applied to electromagnetics: a review  

Microsoft Academic Search

Genetic algorithms are on the rise in electromagnetics as design tools and problem solvers because of their versatility and ability to optimize in complex multimodal search spaces. This paper describes the basic genetic algorithm and recounts its history in the electromagnetics literature. Also, the application of advanced genetic operators to the field of electromagnetics is described, and design results are

Daniel S. Weile; Eric Michielssen

1997-01-01

421

Antenna field calibration laboratory for RF electromagnetic field meters  

Microsoft Academic Search

During recent years, the pronounced electromagnetic pollution of the environment makes it ever more necessary to increase the number of calibrated field strength meters aiming at a better protection of the people and equipment against the electromagnetic radiations. The paper presents the calibration procedure and necessary equipment of RF electromagnetic field meters in the antenna field inside the semi-anechoic chamber

A. Marinescu; A. Scornea; I. Dumbrava; G. Mihai; J. Glimm; K. Munter; R. Pape

2003-01-01

422

Electromagnetic and acoustic emission associated with rock fracture  

Microsoft Academic Search

To understand the physical mechanism of the anomalous electromagnetic emissions observed before earthquakes, we carried out some laboratory experiments on electromagnetic and acoustic emission from a rock. Granitic samples were loaded at a constant strain rate and electromagnetic and acoustic emission were simultaneously recorded during deformation of the sample. Ten to 20% of the acoustic emissions detected during the experiment

I. Yamada; K. Masuda; H. Mizutani

1989-01-01

423

Evolution of electromagnetic field in resonator with nonlinear paramagnetic filling  

Microsoft Academic Search

The problem deals with the evolution of the electromagnetic field inside resonator with the paramagnetic filling is considered. The complex magnetic susceptibility obtained from the Bloch equations has been presented in a form of power series intensity of the electromagnetic field. The solution of evolution equations describing the time dependence of the electromagnetic field inside the resonator under the conditions

S. P. Gavrilov; S. I. Tarapov; A. A. Vertiy; M. E. Özel

1996-01-01

424

Electromagnetic Dancer: Connect Her Up and Watch Her Dance!  

NSDL National Science Digital Library

In this activity, learners use a nail and magnet wire to build an electromagnet, which controls the movements of a paper dancer. Learners will enjoy watching the dancer swirl around when they activate the electromagnet. Use this activity to help learners explore circuits, electromagnets, and currents. Includes pictures, detailed steps for construction, and focus questions to enhance learning.

Workshop, Watsonville E.

2011-01-01

425

Covariant electromagnetic theory for inertial frames with substratum flow  

Microsoft Academic Search

The original Maxwell's equations for the ether rest frame are generalized to electromagnetic field equations for arbitrary inertial frames in which the ether is in a state of motion. The electromagnetic field equations with ether flow w are found to be Galilei covariant, and reduce to the Maxwell equations in the limit w\\/c goes to zero. Electromagnetic signals propagate isotropically

H. E. Wilhelm

1985-01-01

426

Electromagnetic model order reduction for system-level modeling  

Microsoft Academic Search

Reduced-order modeling of an electromagnetic system is understood as the approximation of a continuous or discrete model of the system by one of substantially lower order, yet capable of capturing the electromagnetic behavior of the original one with sufficient engineering accuracy. Specific methodologies for model order reduction of distributed electromagnetic systems are discussed in this paper. It is shown that

Andreas C. Cangellaris; Mustafa Celik; Soheila Pasha; Li Zhao

1999-01-01

427

Irreducible mass and energetics of an electromagnetic black hole  

Microsoft Academic Search

The mass-energy formula for a black hole endowed with electromagnetic structure (EMBH) is clarified for the nonrotating case. The irreducible mass Mirr is found to be independent of the electromagnetic field and explicitly expressable as a function of the rest mass, the gravitational energy and the kinetic energy of the collaps- ing matter at the horizon. The electromagnetic energy is

Remo Ruffinia; Luca Vitagliano

428

Irreducible mass and energetics of an electromagnetic black hole  

Microsoft Academic Search

The mass-energy formula for a black hole endowed with electromagnetic structure (EMBH) is clarified for the nonrotating case. The irreducible mass Mirr is found to be independent of the electromagnetic field and explicitly expressible as a function of the rest mass, the gravitational energy and the kinetic energy of the collapsing matter at the horizon. The electromagnetic energy is distributed

Remo Ruffini; Luca Vitagliano

2002-01-01

429

Questions of energy transformation in dc electromagnetic mechanisms. [Electromagnetic energy to energy of mechanical vibrations  

SciTech Connect

Electromagnetic reciprocal-motion transducers (EMT) are being used ever more extensively in modern industry. In particular, rubble to break down bulkiness, slicer drives for coal combines, drilling equipment, etc. are produced on the basis of EMT. This paper is devoted to further refinement of energy conversion questions and their analysis. The energy coming from the supply source in the magnetization of the additionally sucked-in armature volume is determined by the magnetic energy density in the armature section at the pole level. A general expression is deduced for the electromagnetic force of the EMT that sets up the interrelation between the whole system magnetic energy and the coil flux-linkage. It is shown that expressions known earlier for the electromagnetic forces, obtained for the constant current electromagnet and the constant flux-linkage cases, are particular cases of the general expression that is valid without any additional constraints for the condition of the EMT working process.

Simonov, B.F.

1986-05-01

430

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

431

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

432

Pulsed Electromagnetic Acceleration of Plasma: A Review  

Microsoft Academic Search

Much have been learned about the acceleration mechanisms involved in accelerating a plasma electromagnetically in the laboratory over the last fourty years since the early review by Winston Bostik of 1963, but the accumulated understanding is very much scattered throughout the literature. This literature extends back at least to the early sixties and includes Rosenbluth's snowplow model, discussions by Ralph

Y. C. Francis Thio; Peter J. Turchi; Thomas E. Markusic; Jason T. Cassibry; James C. Sommer

2002-01-01

433

Full Particle Electromagnetic Simulation of Collisionless Shocks  

Microsoft Academic Search

This tutorial-style review is mainly dedicated to the different strategies and constraints used for simulating and analysing the dynamics of collisionless shocks with full particle electromagnetic codes. The relationship between macroscopic and microscopic processes inherent to the shock dynamics and the associated numerical constraints are explained. Different initial methods are commonly used for exciting a shock which are summarized and

Lembege

2003-01-01

434

Electromagnetic launchers: Background and the MRL program  

Microsoft Academic Search

Electromagnetic launchers are studied. These have potential applications in weaponry, controlled thermonuclear fusion, space launch, advanced industrial processes, equation of state research, generation of intense magnetic fields and as facilities for a wide range of studies in penetration mechanics, detonation, and warheads.

Y. C. Thio

1982-01-01

435

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

436

Electromagnetic-Repulsion Systems For Deicing Aircraft  

NASA Technical Reports Server (NTRS)

Improved eddy-current electromagnetic-repulsion deicing systems developed for use on variety of exterior aircraft surfaces like leading edges of wings, engine inlets, propellers, and helicopter rotors. Fit to exterior surfaces, as retrofits or original equipment. Systems light in weight, consume little average power, and capable of protecting against severe icing conditions.

Smith, Samuel O.; Zieve, Peter

1994-01-01

437

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

438

Electromagnetic logging technique based on borehole radar  

Microsoft Academic Search

An electromagnetic logging technique based on borehole radar is introduced in this paper. The tool consists of one transmitter and two receivers, which can be used to cancel the effect of the antenna characteristics by taking the ratio of two receiver signals. Since receiver signals measured in the time domain can be converted into the frequency domain by Fourier transformation,

Sixin Liu; Motoyuki Sato

2002-01-01

439

Electromagnetic Compatibility of Matrix Converter System  

Microsoft Academic Search

Abstract. The presented paper ,deals with matrix converters pulse width modulation strategies design with emphasis on the ,electromagnetic compatibility. Matrix converters provide an all-silicon solution to the problem of converting AC power from one frequency to another, offering almost all the features required of an ideal static frequency changer. They possess many ,advantages compared to the conventional voltage or current

Ji?í Lettl; Stanislav Flígl

440

Electromagnetic Fields and Possible Health Effects  

Microsoft Academic Search

????????????????????.????????????????????????.???,??? ??????,?????????????????????????.?????????????,??????? ?????????????????,????????????????????????????????????. ??????????????,????????????,???????????????.???,?????? ????????????????????????????????????????????????,????? ????????????.????????????????????????????,???????????? ??????????????????.?????????????????0.3-0.4µT ?????,???????? ??????????? µT ????????????,?????????????????????.??,??? ????????????????,13???????????????????????????????????? ?????????.WHO ?14????????????????????????????.?????????? ???????????????0-300GHz ?,??????.?????????,??????????????? ??????.????,WHO ??????????????????????????????????. Abstract Recent years have seen an unprecedented increase in the number and diversity of sources of electromagnetic fields (EMF) used for individual, industrial and commercial purposes. All these technologies have made our life richer and easier. All populations are now exposed to

Chiyoji OHKUBO

441

Pulsing electromagnetic fields induce cellular transcription  

Microsoft Academic Search

Weak, pulsing electromagnetic fields can modify biological processes. The hypothesis that responses to such induced currents depend on pulse characteristics was evaluated by using transcription as the target process. Two pulses in clinical use, the repetitive single pulse and the repetitive pulse train, were tested. These pulses produced different results from each other and from controls when transcription in dipteran

R. Goodman; C. A. Bassett; A. S. Henderson

1983-01-01

442

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

443

IMPROVEMENTS IN OR RELATING TO ELECTROMAGNETIC FLOWMETERS  

Microsoft Academic Search

An electromagnetic flowmeter is designed for operation under high ; temperature and pressure conditions. The flowmeter comprises a body member ; defining a bore and an electrically insulating sleeve loosely lining part of the ; bore. The sleeve is designed so that fluid may penetrate between the sleeve and ; body to balance the pressure across the sleeve. Two diametrically

Thorpe

1962-01-01

444

Electromagnetic Scalar Potentials at a Dielectric Interface.  

National Technical Information Service (NTIS)

The use of scalar potentials in the solution of electromagnetic boundary value problems is described. Explicit solutions of fields at a dielectric interface and at a perfect conductor are derived in terms of the solutions to the wave equation that obey Di...

M. J. Lahart

1996-01-01

445

Electromagnetic De-Shaling of Coal  

Microsoft Academic Search

The efficiency with which an electromagnetic sensor array is able to distinguish density and ash content of coal and shale mixtures was determined experimentally. The investigated sensor was originally designed for automatic metal detection and sorting in industrial glass recycle processing, where it is widely applied. In coal preparation, the results indicate good possibilities to remove automatically the remaining shale

T. P. R. De Jong; M. B. Mesina; W. Kuilman

2003-01-01

446

Electromagnetic Fields and Public Health: Mobile Phones  

MedlinePLUS

Electromagnetic fields and public health: mobile phones Fact sheet N°193 June 2011 Key facts Mobile phone use is ubiquitous with an estimated 4. ... important to investigate, understand and monitor any potential public health impact. Mobile phones communicate by transmitting radio waves ...

447

Electromagnetic compatibility design guideline for STADAN  

NASA Technical Reports Server (NTRS)

Procedures for achieving electromagnetic compatibility in electronic and electrical equipment for aerospace ground stations are investigated. The application of shielding theory to good design is treated and standards of good practice are outlined for bonding, grounding, wiring, and cabling. Some aspects of filter design are explained, and suggestions are given for the application of filters to electronic and electrical equipment.

Cowdell, R. B.; Hill, J. S.; Senn, J. C.; Shifman, J. C.; Skaggs, J. W.

1971-01-01

448

Calibrating Accelerometers Using an Electromagnetic Launcher.  

National Technical Information Service (NTIS)

A Pulse Forming Network (PFN), Helical Electromagnetic Launcher (HEML), Command Module (CM), and Calibration Table (CT) were built and evaluated for the combined ability to calibrate an accelerometer. The PFN has a maximum stored energy of 19.25 kJ bank a...

E. Timpson

2012-01-01

449

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

450

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

451

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

452

Electromagnetic scattering by optically anisotropic magnetic particle  

Microsoft Academic Search

The Mie theory for electromagnetic scattering by spherical particle is extended to the case of magnetic particle with gyromagnetic type of permeability. Specifically, we first construct for the magnetic induction BI inside the particle a new set of vector basis functions, which are the solution of the wave equation for BI and expanded in terms of the usual vector spherical

Zhifang Lin; S. T. Chui

2004-01-01

453

Learning Electromagnetism with Visualizations and Active Learning  

Microsoft Academic Search

This chapter describes learning electromagnetism with visualizations and focuses on the value of concrete and visual representations in teaching abstract concepts. We start with a theoretical background consisting of three subsections: visualization in science, simulations and microcomputerbased laboratory, and studies that investigated the effectiveness of simulations and real-time graphing in physics. We then present the TEAL (Technology Enabled Active Learning)

YEHUDIT JUDY DORI; John Belcher

454

Superconductive Levitated Armatures for Electromagnetic Launchers.  

National Technical Information Service (NTIS)

An electromagnetic railgun launcher and armature. The armature is made from superconducting material and is levitated between the rails of the launcher by the Meissner effect. The Meissner effect is created by cooling the armature and subjecting it to a m...

L. J. Jasper

1988-01-01

455

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

456

Human Health and Exposure to Electromagnetic Radiation.  

National Technical Information Service (NTIS)

This review consists of three main parts. In the first the general features of electromagnetic fields and their interactions with the human body are described. It is pointed out that some evidence from biological experiments means that it is not a priori ...

J. A. Dennis C. R. Muirhead J. R. Ennis

1992-01-01

457

Alternating current electromagnetic servo induction meter  

NASA Technical Reports Server (NTRS)

Electromagnetic device accurately indicates the responses of various sensors in high performance flight research aircraft to conditions encountered in flight. The device responds to sensor inputs to move a slideable armature along an indicator scale by the force of currents induced in the armature winding.

Bogue, R. K.

1968-01-01

458

Medical application of slow electromagnetic waves  

Microsoft Academic Search

The development and realization of microwave radiators, based on slow-wave structures (SWS) application, has shown that the application of slow electromagnetic waves is extremely promising in different areas of medicine. A novel family of RF applicators and microwave radiators is offered and designed. An artificial ear with antenna on coupled spirals and coagulating scalpels with coupled combs on metal and

Yu. N. Pchelnikov; A. A. Yelizarov

1999-01-01

459

Scattering of Electromagnetic Waves, Theories and Applications  

NASA Astrophysics Data System (ADS)

A timely and authoritative guide to the state of the art of wave scattering Scattering of Electromagnetic Waves offers in three volumes a complete and up-to-date treatment of wave scattering by random discrete scatterers and rough surfaces. Written by leading scientists who have made important contributions to wave scattering over three decades, this new work explains the principles, methods, and applications of this rapidly expanding, interdisciplinary field. It covers both introductory and advanced material and provides students and researchers in remote sensing as well as imaging, optics, and electromagnetic theory with a one-stop reference to a wealth of current research results. Plus, Scattering of Electromagnetic Waves contains detailed discussions of both analytical and numerical methods, including cutting-edge techniques for the recovery of earth/land parametric information. The three volumes are entitled respectively Theories and Applications, Numerical Simulation, and Advanced Topics. In the first volume, Theories and Applications, Leung Tsang (University of Washington) Jin Au Kong (MIT), and Kung-Hau Ding (Air Force Research Lab) cover: Basic theory of electromagnetic scattering Fundamentals of random scattering Characteristics of discrete scatterers and rough surfaces Scattering and emission by layered media Single scattering and applications Radiative transfer theory and solution techniques One-dimensional random rough surface scattering

Tsang, Leung; Kong, Jin Au; Ding, Kung-Hau

2000-07-01

460

Transient electromagnetic wave propagation in waveguides  

Microsoft Academic Search

This paper focuses on propagation of transient electromagnetic waves in waveguides of general cross section with perfectly conducting walls. The solution of the transient wave propagation problem relies on a wave splitting technique, which has been frequently used in direct and inverse scattering problems during the last decade. The field in the waveguide is represented as a time convolution of

Gerhard Kristensson

1995-01-01

461

The behavior of electromagnetic fields at edges  

Microsoft Academic Search

The behavior of an electromagnetic field in the neighborhood of the common edge of angular dielectric or conducting regions is determined from the condition that the energy density must be integrable over any finite domain (the so-called edge condition). Two cases are treated in detail 1) A region consisting of a conducting wedge and two different dielectric wedges with a

J. Meixner

1972-01-01

462

The Good, the Bad and the Electromagnet  

NSDL National Science Digital Library

Using plastic straws, wire, batteries and iron nails, student teams build and test two versions of electromagnetsâone with and one without an iron nail at its core. They test each magnet's ability pick up loose staples, which reveals the importance of an iron core to the magnet's strength. Students also learn about the prevalence and importance of electromagnets in their everyday lives.

USF STARS (GK-12 Program),

463

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

464

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

465

Nuclear Electromagnetic Pulse (NEMP) Hardened Cables.  

National Technical Information Service (NTIS)

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 shea...

W. C. Wells Y. Shiau

1976-01-01

466

Electromagnetic pulse and the electric power network  

Microsoft Academic Search

The nuclear electromagnetic pulse (EMP) - electric power system interaction problem is defined. 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

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

1984-01-01

467

Electromagnetic Pulse and the Electric Power Network  

Microsoft Academic Search

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

Kenneth Klein; Paul Barnes; Henry Zaininger

1985-01-01

468

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

469

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

470

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

471

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

472

The electromagnetic pulse from nuclear detonations  

Microsoft Academic Search

Models of the processes whereby a nuclear detonation emits a coherent electromagnetic pulse fall into three classes: those involving Compton electron currents produced by interaction of prompt ? radiation from the detonation with the environment, those involving photoelectron currents produced by the similar interaction of primary X radiation from the detonation, and those involving perturbation of the ambient magnetic field

Gary H. Price

1974-01-01

473

Radiated fields from an electromagnetic pulse simulator  

Microsoft Academic Search

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

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

1990-01-01

474

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

475

Electromagnetic pulse from final gravitational stellar collapse  

Microsoft Academic Search

We employ an effective gravitational stellar final collapse model which contains the relevant physics involved in this complex phenomena: spherical radical infall in the Schwarzschild metric of the homogeneous core of an advanced star, giant magnetic dipole moment, magnetohydrodynamic material response and realistic equations of state (EOS). The electromagnetic pulse is computed both for medium size cores undergoing hydrodynamic bounce

P. D. Morley; Ivan Schmidt

2002-01-01

476

Control strategies for Maglev electromagnetic suspension bogies  

Microsoft Academic Search

Two electromagnetic suspensions have been successfully realised for low speed Maglev operation: the High Speed Surface Transport (HSST) Maglevs, and the GEC-Alsthom Birmingham Maglev which operated from 1984 until 1995. The two design strategies are quite different. The former, designed initially for high speed (>200 km\\/h), employs a magnetic primary and an air spring secondary suspension enabling higher speed operation

J. E. Paddison; H. Ohsaki; E. Masada

1996-01-01

477

Electromagnetic probes of quark gluon plasma  

Microsoft Academic Search

In very energetic collisions of heavy ions, a novel state of matter — quark gluon plasma — is expected to be transiently formed. We review the suitability of electromagnetically interacting particles, dilepton pairs, single photons, diphotons, etc., as diagnostic tools for quark gluon plasma.

Jan-e Alam; Sibaji Raha; Bikash Sinha

1996-01-01

478

Neutrino-helium ionizing collisions: Electromagnetic contribution  

NASA Astrophysics Data System (ADS)

In terrestrial experiments searching for neutrino magnetic moments one investigates the ionization channel in the neutrino-atom scattering. We present numerical calculations that disprove the recent theoretical claim about large enhancement of the electromagnetic-interaction contribution to the neutrino impact ionization of helium relative to the case of the neutrino scattering on free electrons.

Kouzakov, Konstantin A.; Rodina, Yulia A.; Studenikin, Alexander I.

2014-04-01

479

Relativistic particle motion in nonuniform electromagnetic waves  

NASA Technical Reports Server (NTRS)

A charged particle moving in a strong nonuniform electromagnetic wave which suffers a net acceleration in the direction of the negative intensity gradient of the wave was investigated. Electrons will be expelled perpendicularly from narrow laser beams and various instabilities result.

Schmidt, G.; Wilcox, T.

1973-01-01

480

AN ELECTROMAGNETIC SHOCK TUBE FOR AERODYNAMIC RESEARCH  

Microsoft Academic Search

An electromagnetically driven shock tube was studied as a possible new ; tool for aerodynamic research in which velocities of up to 41,000 fps are ; obtainable in air. At these high velocities stagnation temperatures of about ; 35,000 deg K are produced. The simple construction and operation of the shock ; tube is described and an evaluation is made

Ziemer

1958-01-01

481

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

482

The Electromagnetic Spectrum: Wavelength and Energy  

NSDL National Science Digital Library

In this activity, students demonstrate the relationship between wave frequency and energy in the electromagnetic spectrum by shaking a rope to identify the relationships. This activity is part of Unit 2 in the Space Based Astronomy guide that contains background information, worksheets, assessments, extensions, and standards.

483

Electromagnetic Analysis of Reentrant Klystron Cavity  

NASA Astrophysics Data System (ADS)

The mathematically simple formalism proposed earlier for calculating electromagnetic parameters of a reentrant cavity Barroso et al. (International Journal of Infrared and Millimeter Waves 26(8):1071-1083, 2005) is improved in usability by proposing a closed form solution for the parameter connecting two asymptotic regions of very small and very large gaps. The results obtained are verified with earlier reported results.

Tiwari, Ashish Kumar; Hannurkar, P. R.

2010-10-01

484

Nucleon electromagnetic form factors in QCD  

SciTech Connect

The nucleon electromagnetic form factors are calculated in a light cone QCD sum rules framework using the most general form of the nucleon interpolating current. Using two models for the distribution amplitudes, we predict the form factors. The predictions are also compared with existing experimental data. It is shown that our results describe remarkably well the existing experimental data.

Aliev, T. M.; Azizi, K.; Ozpineci, A.; Savci, M. [Physics Department, Middle East Technical University, 06531, Ankara (Turkey)

2008-06-01

485

Microcirculatory effects of pulsed electromagnetic fields  

Microsoft Academic Search

Purpose: Pulsed electromagnetic fields (PEMF) are used clinically to expedite healing of fracture non-unions, however, the mechanism of action by which PEMF stimulation is effective is unknown. The current study examined the acute effects of PEMF stimulation on arteriolar microvessel diameters in the rat cremaster muscle. The study hypothesis was that PEMF would increase arteriolar diameters, a potential mechanism involved

Thomas L. Smith; Donna Wong-Gibbons; Jane Maultsby

2004-01-01

486

Electromagnetic particle codes on unstructured grids  

NASA Astrophysics Data System (ADS)

The most widely used computational model of collisionless plasmas is the Lagrangian-Eulerian hybrid technique known as particle-in-cell or PIC. In the electromagnetic version, Maxwell's equations are solved on an Eulerian grid and electromagnetic forces are interpolated from the grid to particle locations. Particles are then moved in Lagrangian fashion while their currents are interpolated back onto the grid to provide sources for the fields on the next cycle. There are many applications where one needs to model plasmas and electromagnetic waves inside regions of complicated shape. Traditional methods for solving Maxwell's equations employ finite differences on regular grids to replace differential operators. These methods are awkward for complicated boundary shapes, often replacing smoothly curved or slanted boundaries with stairsteps. The desire to incorporate realistic boundaries into plasma simulations is motivated by a host of situations in which proper representation of the boundary shape is expected to be critical. The approach to solving this problem is to design electromagnetic particle codes based on the use of unstructured grids. The arbitrary connectivity of unstructured grids provides the flexibility to place nodes wherever needed to fit the most complex boundary shapes. The most significant problems that must be addressed as a result of this strategy are grid generation, field solution, and particle tracking. The solutions to these problems, along with a few preliminary results, are presented.

Ambrosiano, John J.; Brandon, Scott T.; Loehner, Rainald

1990-06-01

487

Electromagnetic Wave Interactions with a Metamaterial Cloak  

Microsoft Academic Search

We establish analytically the interactions of electromagnetic wave with a general class of spherical cloaks based on a full wave Mie scattering model. We show that for an ideal cloak the total scattering cross section is absolutely zero, but for a cloak with a specific type of loss, only the backscattering is exactly zero, which indicates the cloak can still

Hongsheng Chen; Bae-Ian Wu; Baile Zhang; Jin Au Kong

2007-01-01

488

ELECTROMAGNETIC ARTICULOGRAPHY IN COARTICULATION RESEARCH1  

Microsoft Academic Search

This paper gives an overview of the basic methodological issues relevant to the use of electromagnetic articulography in experimental phonetics. The following topics are covered: measurement principle, sources of error, environmental conditions, combination with other equipment, disturbances to the subjects' speech, safety. Finally, an example is given of how this technique can provide new information on lingual articulation even within

Philip Hoole; Noel Nguyen

1996-01-01

489

Planar Electromagnet Microwiggler for Free Electron Lasers.  

National Technical Information Service (NTIS)

An electromagnet planar microwiggler for use in free electron lasers was tested, constructed of current conductors wound on ferromagnetic cores. A prototype with a period of 1 cm and gap of 0.5 cm produced a peak field on axis in excess of 4.6 kG, with a ...

R. Stoner S. C. Chen G. Bekefi

1990-01-01

490

Electromagnetic Acoustic Transducers (EMATs) for erosion monitoring  

Microsoft Academic Search

Advantages of electromagnetic transducer (EMAT-based) systems motivated a study to establish criteria and requirements needed for erosion monitoring at elevated (operating) temperatures. The effort concentrated on three areas: (1) development of EMAT design parameters, (2) material-EMAT interaction, and (3) signal processing. Prototype horizontal shearwave EMATs, based on design parameters selected from computer calculations of the static field, were evaluated, and

K. J. Reimann

1984-01-01

491

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

492

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

493

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.

494

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

495

Calculating Electromagnetic Fields Of A Loop Antenna  

NASA Technical Reports Server (NTRS)

Approximate field values computed rapidly. MODEL computer program developed to calculate electromagnetic field values of large loop antenna at all distances to observation point. Antenna assumed to be in x-y plane with center at origin of coordinate system. Calculates field values in both rectangular and spherical components. Also solves for wave impedance. Written in MicroSoft FORTRAN 77.

Schieffer, Mitchell B.

1987-01-01

496

Characteristics of Electromagnetic Pulse Propagation in Metal.  

National Technical Information Service (NTIS)

It is well known that the solution of the diffusion equation for an electromagnetic field with a time harmonic term, e(sup iax), is in the form of a traveling wave whose amplitude attenuates over distance into a conducting medium. As the attenuation is an...

M. Namkung B. Wincheski S. Nath

2004-01-01

497

Ether drift experiments and electromagnetic momentum  

NASA Astrophysics Data System (ADS)

Propagation of Aharonov-Bohm matter waves and light waves in moving media is characterized by the interaction electromagnetic momentum. Thus, recent models of light propagation in moving rarefied media justify and call for an optical experiment of the Mascart-Jamin type, capable of testing the modern interpretations of ether drift experiments.

Spavieri, G.; Guerra, V.; de Abreu, R.; Gillies, G. T.

2008-05-01

498

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.

499

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

500

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