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1

Visual field deficit due to downward displacement of optic chiasm  

Microsoft Academic Search

Visual disturbance in hydrocephalus is typically due to raised intracranial pressure. We describe a patient who presented\\u000a with marked loss of peripheral visual fields, but without features suggestive of raised intracranial pressure. MR scan showed\\u000a an enlarged third ventricle and a downward displacement of the optic chiasm, Chiari II malformation. These radiological changes\\u000a and the visual field deficits reversed after

Daniel Holsgrove; Paul Leach; Amit Herwadkar; Kanna K. Gnanalingham

2009-01-01

2

Role of plasma response in displacements of the tokamak edge due to applied non-axisymmetric fields  

NASA Astrophysics Data System (ADS)

Linear, two-fluid, resistive modelling of the plasma response to applied non-axisymmetric fields shows significant displacement of edge temperature and density profiles. The calculated displacements, often of 2 cm or more in H-mode pedestals with parameters appropriate to DIII-D, are due to the helical distortions resulting from stable edge modes being driven to finite amplitude by the applied fields. In many cases, these displacements are greater in magnitude, and different in phase, than the distortions of the separatrix manifolds predicted from vacuum modelling. Comparison of these results with experimental measurements from Thomson scattering and soft x-ray imaging finds good quantitative agreement. In these experiments, the phase of the applied non-axisymmetric magnetic field was flipped or rotated in order to probe the non-axisymmetric features of the response. The poloidal structures measured by x-ray imaging show clear indications of a helical response, as opposed to simply a change in the axisymmetric transport. Inclusion of two-fluid effects and rotation are found to be important in obtaining quantitative agreement with Thomson scattering data. Modelling shows screening of islands in the H-mode pedestal, but island penetration near the top of the pedestal where the electron rotation vanishes in plasmas with co-current rotation. Enhanced transport due to these islands may provide a mechanism for maintaining the pedestal width below the stability threshold of edge-localized modes. For typical DIII-D parameters, it is shown that the linear approximation is often near or beyond the limit of validity in the H-mode edge; however, the general agreement with experimental measurements indicates that these linear results nevertheless maintain good predictive value for profile displacements.

Ferraro, N. M.; Evans, T. E.; Lao, L. L.; Moyer, R. A.; Nazikian, R.; Orlov, D. M.; Shafer, M. W.; Unterberg, E. A.; Wade, M. R.; Wingen, A.

2013-07-01

3

Role of plasma response in displacements of the tokamak edge due to applied non-axisymmetric fields  

SciTech Connect

Linear, two-fluid, resistive modelling of the plasma response to applied non-axisymmetric fields shows significant displacement of edge temperature and density profiles. The calculated displacements, often of 2 cm or more in H-mode pedestals with parameters appropriate to DIII-D, are due to the helical distortions resulting from stable edge modes being driven to finite amplitude by the applied fields. In many cases, these displacements are greater in magnitude, and different in phase, than the distortions of the separatrix manifolds predicted from vacuum modelling. Comparison of these results with experimental measurements from Thomson scattering and soft x-ray imaging finds good quantitative agreement. In these experiments, the phase of the applied non-axisymmetric magnetic field was flipped or rotated in order to probe the non-axisymmetric features of the response. The poloidal structures measured by x-ray imaging show clear indications of a helical response, as opposed to simply a change in the axisymmetric transport. Inclusion of two-fluid effects and rotation are found to be important in obtaining quantitative agreement with Thomson scattering data. Modelling shows screening of islands in the H-mode pedestal, but island penetration near the top of the pedestal where the electron rotation vanishes in plasmas with co-current rotation. Enhanced transport due to these islands may provide a mechanism for maintaining the pedestal width below the stability threshold of edge-localized modes. For typical DIII-D parameters, it is shown that the linear approximation is often near or beyond the limit of validity in the H-mode edge; however, the general agreement with experimental measurements indicates that these linear results nevertheless maintain good predictive value for profile displacements.

Evans, T. E. [General Atomics, San Diego; Ferraro, N. M. [General Atomics, San Diego; Orlov, D. M. [University of California, San Diego & La Jolla; Wade, M. [General Atomics, San Diego; Lao, L. L. [General Atomics, San Diego; Moyer, R. A. [University of California, San Diego; Wingen, A. [University of Dusseldorf, Germany; Nazikian, R. [Princeton Plasma Physics Laboratory (PPPL); Unterberg, Ezekial A [ORNL; Shafer, Morgan W [ORNL

2013-01-01

4

SYSTEMIC TOXICITY REACTIONS DUE TO EPIDURAL CATHETER DISPLACEMENT  

Microsoft Academic Search

Toxic reactions to local anesthetics may occur due to over dose, accidental intravenous injections or rapid systemic uptake of the drugs. But there have been few reports on toxicity due to displacement of epidural catheters after an initial correct insertion and performance of a test dose. Here we present a case of local anesthetics toxicity due to possible displacement of

M. H. Ghafari; M. Akrami; M. Sadeghi; M. Ghoreishinejad

5

Crustal displacements due to continental water loading  

NASA Astrophysics Data System (ADS)

The effects of long-wavelength (>100 km), seasonal variability in continental water storage on vertical crustal motions are assessed. The modeled vertical displacements (?rM) have root-mean-square (RMS) values for 1994-1998 as large as 8 mm, with ranges up to 30 mm, and are predominantly annual in character. Regional strains are on the order of 20 nanostrain for tilt and 5 nanostrain for horizontal deformation. We compare ?rM with observed Global Positioning System (GPS) heights (?rO) (which include adjustments to remove estimated effects of atmospheric pressure and annual tidal and non-tidal ocean loading) for 147 globally distributed sites. When the ?rO time series are adjusted by ?rM, their variances are reduced, on average, by an amount equal to the variance of the ?rM. Of the ?rO time series exhibiting a strong annual signal, more than half are found to have an annual harmonic that is in phase and of comparable amplitude with the annual harmonic in the ?rM. The ?rM time series exhibit long-period variations that could be mistaken for secular tectonic trends or postglacial rebound when observed over a time span of a few years.

van Dam, T.; Wahr, J.; Milly, P. C. D.; Shmakin, A. B.; Blewitt, G.; Lavallée, D.; Larson, K. M.

6

Point processes and stochastic displacement fields.  

PubMed

The effect of a stochastic displacement field on a statistically independent point process is analyzed. Stochastic displacement fields can be divided into two large classes: spatially correlated and uncorrelated. For both cases exact transformation equations for the two-point correlation function and the power spectrum of the point process are found, and a detailed study of them with important paradigmatic examples is done. The results are general and in any dimension. Particular attention is devoted to the kind of large-scale correlations that can be introduced by the displacement field and to the realizability of arbitrary "superhomogeneous" point processes. PMID:15697458

Gabrielli, Andrea

2004-12-23

7

Asymptomatic Motor Cortex Displacement due to a Giant Arachnoid Cyst  

Microsoft Academic Search

Cerebral lesions are held to induce plastic changes of the brain. Less well established, however, is how much space-occupying brain lesions may only displace functional representations. In a 66-year-old man we show, by means of functional magnetic resonance imaging and transcranial magnetic stimulation, a profound displacement of the motor cortex due to a large asymptomatic arachnoid cyst. Thus, the chronically

J. Nickel; S. Jörgens; P. Bussfeld; R. J. Seitz

2008-01-01

8

BLOCK DISPLACEMENT METHOD FIELD DEMONSTRATION AND SPECIFICATIONS  

EPA Science Inventory

The Block Displacement technique has been developed as a remedial action method for isolating large tracks of ground contaminated by hazardous waste. The technique places a low permeability barrier around and under a large block of contaminated earth. The Block Displacement proce...

9

Deformations of the Earth's mantle due to core displacements  

NASA Astrophysics Data System (ADS)

The planet is assumed to consist of an absolutely rigid sphere to which the viscous elastic spherical shell (the mantle) is connected from the external side. In the undeformed state the centres of mass of the mantle and the core coincide and the shells have concentric positions. The centre of mass of the core is considered to be displaced according to a definite law relative to the centre of mass of the mantle in its undeformed state among to the differential action from external celestial bodies. The solution of the problem of elasticity is obtained using a restricted treatment by taking into account only the mutual interaction of the mantle and the moving core and by neglecting the non-sphericities of the core and the mantle. The corresponding effects of the mantle deformations caused by the external bodies are known and can be studied separately on the basis of the principle of superposition. The deformations of the Earth’s mantle due to secular drift of the core along the polar axis are described. The phenomenon of the contrasting tendencies in the deformations northern and southern hemispheres of the Earth (expansion and contraction, respectively) is discovered. The evaluation of the velocity of the core drift relative to the mantle’s centre of mass has been obtained and was found to be equal to 8.0cm year-1.

Barkin, Yu. V.; Shatina, A. V.

2005-06-01

10

Block Displacement Method Field Demonstration and Specifications.  

National Technical Information Service (NTIS)

The Block Displacement technique has been developed as a remedial action method for isolating large tracks of ground contaminated by hazardous waste. The technique places a low permeability barrier around and under a large block of contaminated earth. The...

T. P. Brunsing

1987-01-01

11

Articular disk displacement of TMJ due to trauma.  

PubMed

One hundred and thirty native American Indian patients undergoing orthodontic treatment for malocclusions were screened for temporomandibular joint (TMJ) abnormalities. These patients were followed over the course of orthodontic treatment and six of these patients suffered a traumatic injury to the TMJ. These six patients who had been previously screened and found to be asymptomatic, developed symptoms. Three were diagnosed with articular disk displacement of the TMJ confirmed by magnetic resonance imaging (MRI). PMID:8242786

Goddard, G

1993-07-01

12

Microscopic 3-D displacement field measurements using digital speckle photography  

Microsoft Academic Search

A technique to measure object shape and 3-D displacement fields in micro-scale is offered by microscopic stereo digital speckle photography. The displacement of the random features that are often present on many engineering surfaces when viewed in a microscope is measured with the system, using image correlation. In this paper the equipment, physical model and calibration routines are described. The

Linda Larsson; Mikael Sjödahl; Fredrik Thuvander

2004-01-01

13

Characterization of damaged composite laminates by an optical measurement of the displacement field  

NASA Astrophysics Data System (ADS)

The degradation of the elastic properties of composite laminates with intralaminar cracks is caused by reduced stress in the damaged layer which is mainly due to two parameters: the crack opening displacement (COD) and the crack sliding displacement (CSD). In this paper these parameters are measured experimentally providing laminate stiffness reduction models with valuable information for validation of used assumptions and for defining limits of their application. In particular, the displacement field on the edges of a [0/ +704/ -704]s glass fiber/epoxy laminate specimens with multiple intralaminar cracks is studied and the COD and CSD dependence on the applied mechanical load is measured. The specimen full-field displacement measurement is carried out using ESPI (Electronic Speckle Pattern Interferometry). By studying the displacement discontinuities, the crack face displacements were measured. A comparison between the COD and the CSD (for the same crack) is performed.

Loukil, M. S.; Varna, J.; Ayadi, Z.

2012-02-01

14

Identifi cation of elastic parameters by displacement field measurement  

Microsoft Academic Search

In this Note we study a parameter identification problem associated with a two-dimensional mechanical problem. In a first part, the experimental technique of determining the displace- ment field is presented. The variational method proposed herein is based on the minimiza- tion of a separately convex functional which leads to the reconstruction of the elastic tensor and the stress field. These

Giuseppe Geymonat; Francois Hild; Stephane Pagano

15

Fuzzy models for analysis of rock mass displacements due to underground mining in mountainous areas  

Microsoft Academic Search

The displacement and deformations of rock mass due to underground mining has often resulted in major disasters throughout the world, frequently inflicting heavy losses of life and damage to property. And these disasters have motivated the development of rock mass mechanics. The prediction of displacement of rock mass and their surface effects is an important problem of the rock mass

Wenxiu Li; Songhua Mei; Shuhua Zai; Shengtao Zhao; Xuli Liang

2006-01-01

16

Mechanisms of In Situ Rock Displacement During Hypervelocity Impact: Field and Microscopic Observations  

NASA Astrophysics Data System (ADS)

The nature of rock deformation due to hypervelocity impact is discussed, especially with regard to the larger terrestrial structures (e.g., Sudbury, Vredefort, Manicouagan). Based on field observations and thin section microscopy, evidence is presented for two end-members of rock response to extreme strain rates: (1) bulk deformation, due to pervasive fracture generation and ensuing micro-displacement with melting; (2) localized large-displacement faulting, accompanied by friction melt generation (pseudotachylytes). There is no evidence for bulk "fluidization" at the thin section scale, except where bulk melting has occurred during impact melt sheet generation, wherein truly fluid (igneous) rocks are formed.

Spray, J. G.

2003-02-01

17

Measuring Electric Field Induced Subpicometer Displacement of Step Edge Ions  

NASA Astrophysics Data System (ADS)

We provide unambiguous evidence that the applied electrostatic field displaces step atoms of ionic crystal surfaces by subpicometers in different directions via the measurement of the lateral force interactions by bimodal dynamic force microscopy combined with multiscale theoretical simulations. Such a small imbalance in the electrostatic interaction of the shifted anion-cation ions leads to an extraordinary long-range feature potential variation and is now detectable with the extreme sensitivity of the bimodal detection.

Kawai, Shigeki; Canova, Filippo Federici; Glatzel, Thilo; Hynninen, Teemu; Meyer, Ernst; Foster, Adam S.

2012-10-01

18

Full-field representation of discretely sampled surface deformation for displacement and strain analysis  

Microsoft Academic Search

A detailed evaluation of the feasibility of determining displacements and displacement gradients from measured surface displacement fields is presented. An improved methodology for both the estimation and elimination of noise is proposed. The methodology is used to analyze the gradients for three tests: (1) uniform rotation, (2) uniform strain, and (3) crack-tip displacement fields. Results of the study indicate that

M. A. Sutton; J. L. Turner; H. A. Bruck; T. A. Chae

1991-01-01

19

PREDICTION OF SURFACE SETTLEMENT DUE TO THE DISPLACEMENT OF SOFT ZONES  

SciTech Connect

In areas composed of coastal plain sediments, soft zones subjected to partial overburden may be present in the subsurface. During or after a seismic event, these soft zones may be compressed. The resulting displacement due to the deformation of the soft zones will propagate to the ground surface and cause the surface to settle. This paper presents a method to predict the settlement at the surface due to the propagation of the displacement from the soft zones. This method is performed by discretizing the soft zones into multiple clusters of finite sub-areas or subspaces. Settlement profile at the ground surface due to the displacement of each sub-area or subspace is computed assuming the shape is a normal distribution function. Settlement due to the displacement of the soft zones can then be approximated by adding the settlements computed for all the sub-areas or subspaces. This method provides a simple and useful tool for the prediction of the settlement profile and the results are consistent with those obtained from the finite difference analysis.

Li, W

2008-03-03

20

Determination of displacements at the boundary of a body due to discontinuities in the medium  

SciTech Connect

The problem of determining the displacements at the boundary of a body due to instantaneous disturbance of the continuity of the medium inside the body, i.e. discontinuities over a certain finite surface S, is of particular interest in connection with the inspection of structural elements, prediction of the probable effects of earthquakes, and the study of other processes. Three-dimensional problems - which more adequately reflect the actual physical processes that take place - are especially interesting in this regard. Here, we use an elastic half-space as an example to study the dependence of the displacements at its boundary on the instantaneous formation of discontinuities inside the half-space over a certain finite plane surface S. To solve this problem with allowance for its three-dimensional nature, we will examine a half-space weakened by plane slits whose opposing surfaces are displaced relative to one another over the period of time t in accordance with a certain law. Conditionally assuming that this law is known, we determine the displacements that these displacements cause at the boundary of the body. The boundary is assumed to be free of external forces.

Stankevich, V.Z.; Khai, M.V. [Institute of Applied Problems of Mechanics and Mathematics, Lvov (Ukraine)

1995-06-01

21

An Investigation of Smoothness Constraints for the Estimation of Displacement Vector Fields from Image Sequences  

Microsoft Academic Search

A mapping between one frame from an image sequence and the preceding or following frame can be represented as a displacement vector field. In most situations, the mere gray value variations do not provide sufficient information in order to estimate such a displacement vector field. Supplementary constraints are necessary, for example the postulate that a displacement vector field varies smoothly

Hans-Hellmut Nagel; Wilfried Enkelmann

1986-01-01

22

Usefulness of synthetic aperture radar (SAR) interferometry for digital elevation model (DEM) generation and estimation of land surface displacement in Jharia coal field area  

Microsoft Academic Search

Land surface displacement is a phenomenon of ground movement, which may occur due to various reasons including unplanned mining. The quantification of land surface displacement through conventional field surveys is based on sparingly distributed point data, which may be insufficient for many applications. A detailed spatial and temporal monitoring of land surface displacements through remote sensing-based synthetic aperture radar (SAR)

Atanu Bhattacharya; Manoj K. Arora; Mukat L. Sharma

2011-01-01

23

Usefulness of synthetic aperture radar (SAR) interferometry for digital elevation model (DEM) generation and estimation of land surface displacement in Jharia coal field area  

Microsoft Academic Search

Land surface displacement is a phenomenon of ground movement, which may occur due to various reasons including unplanned mining. The quantification of land surface displacement through conventional field surveys is based on sparingly distributed point data, which may be insufficient for many applications. A detailed spatial and temporal monitoring of land surface displacements through remote sensing-based synthetic aperture radar (SAR)

Atanu Bhattacharya; Manoj K. Arora; Mukat L. Sharma

2012-01-01

24

Displacement field estimation using a coupled Gauss-Markov model  

NASA Astrophysics Data System (ADS)

In this paper, we develop a model-based algorithm for obtaining the maximum a posteriori (MAP) estimate of the displacement vector field (DVF) from two consecutive image frames of an image sequence. To model the DVF, we develop a nonstationary vector field model called the Vector Coupled Gauss-Markov (VCGM) model. The VCGM model is well suited for estimating the DVF, since the resulting estimates preserve the boundaries between the moving and stationary areas in an image sequence. Thus, the model-based MAP estimator that we develop has the ability to adapt to the discontinuities of the DVF. Experiments with a typical video-conferencing sequence demonstrate the superior performance of the proposed algorithm with respect to prediction error and robustness to occlusions.

Brailean, James C.; Katsaggelos, Aggelos K.

1992-08-01

25

Apparent spatial blurring and displacement of a point optical source due to cloud scattering  

SciTech Connect

A Monte Carlo algorithm is used to determine the apparent spatial blurring of a terrestrial 1.07 micron optical point source due to cloud scattering as seen from space. The virtual image of a point source over a virtual source plane area 22.4 x 22.4 square kilometers arising from cloud scattering was determined for stratus clouds (NASA cloud number 5) and altostratus clouds optical source arises from photon scattering by cloud water droplets. Displacement of the virtual source is due to the apparent illumination of the cloud top region directly about the actual source which when viewed at a nonzero look angle gives a projected displacement of the apparent source relative to the actual source. These features are quantified by an analysis of the Monte Carlo computational results.

Brower, K.L.

1997-09-01

26

Displacements due to surface temperature variation on a uniform elastic sphere with its centre of mass stationary  

NASA Astrophysics Data System (ADS)

We investigate the displacement field induced by temperature variation within a spherical thermal boundary layer under an Earth-like condition of surface heating by deriving analytical solutions on a uniform elastic sphere under the constraint that its centre of mass remains stationary in space. Similar to strain solutions, our displacement solution consists of spectra of two distinctive modes: an exponential mode relating to the thermal body force and a power-law mode relating to the (equivalent) thermal surface loading. The exponential modes of the thermal body force in our solution turn out to be identical to that in a classic half-space solution, while the effect of thermal loading by the power-law modes in our spherical solution is different from the exponential modes of thermal loading in the half-space solution. The thermal surface loading is found, by analytical and numerical analyses, equally important in order of magnitude as the thermal body force in producing the radial displacement at the surface throughout the entire harmonic spectrum. The transverse displacement arises mainly from the power-law modes of thermal surface loading. Numerical simulations, based on NASA's space-borne observation of the global land surface temperature (ocean is masked out), have shown unique patterns in the annual variation of the global displacement field that fits the climatological and geographical settings. The predicted amplitude of the thermally induced surface deformation in global scale is at the millimetre level with the largest ˜2 mm for radial displacement and ˜1 mm for transverse displacement. Comparative analysis shows that the radial displacement field is asymptotically proportional to the surface temperature distribution, which justifies the use of the half-space solution as a good approximation for modelling the global radial displacement. The transverse displacement obtained by patched half-space solution fails to capture the long-range transverse variations on a spherical surface, and thus, is inadequate for modelling and synthesizing the global transverse displacement.

Fang, Ming; Dong, Danan; Hager, Bradford H.

2013-10-01

27

HEMP-Hand-Displacement-Based Pseudo-Haptics: A Study of a Force Field Application  

Microsoft Academic Search

Abstract This paper introduces a novel pseudo-haptic approach called HEMP - hand-displacement-based pseudo-haptics. The main idea behind HEMP is to provide haptic-like sensations by dynamically displacing the visual representation of the user's hand. This paper studies the possible application of HEMP to the simulation of force fields (FF). The proposed hardware solution for simulating the hand displacement is based on

Andreas Pusch; Olivier Martin; Sabine Coquillart

2008-01-01

28

Horizontal viscoelastic-gravitational displacement due to a rectangular dipping thrust fault in a layered Earth model  

Microsoft Academic Search

Calculations of horizontal displacements due to a rectangular finite thrust fault in a viscoelastic-gravitational layered Earth model are presented. The Earth model consists of a single elastic-gravitational layer overlying a viscoelastic-gravitational half-space. A review of the full three-dimensional theoretical solutions is presented along with the explicit solutions for horizontal displacements. Several examples of computations for dipping faults with various angles,

José Fernández; Ting-To Yu; John B. Rundle

1996-01-01

29

On the derivation of coseismic displacement fields using differential radar interferometry: The Landers earthquake  

Microsoft Academic Search

Presents a map of the coseismic displacement field resulting from the Landers, CA, June 28, 1992 earthquake derived using data acquired from an orbiting high resolution radar system. Data from the ERS-1 synthetic aperture radar instrument acquired in April, July, and August 1992 are used to generate a high resolution, wide area map of the displacements. The data represent the

HOWARD A. ZEBKER; PAUL ROSEN

1994-01-01

30

Macroscopic superposition and entanglement for displaced thermal fields induced by a single atom  

Microsoft Academic Search

We show that a cavity field can evolve from an initial displaced mixed thermal state to a macroscopic superpositions of displaced thermal states via resonant interaction with a two-level atom. As a macroscopic system (meter) is really in a mixed state before coupling with the microscopic system at some temperature, our result is important for studying the quantum measurement problem

Shi-Biao Zheng

2007-01-01

31

Constraints for the Estimation of Displacement Vector Fields From Image Sequences  

Microsoft Academic Search

Smoothness constraints have been used to facili­ tate the estimation of displacement vector fields. Differing from HORN and SCHUNCK 81 who employ a general smoothness requirement, this contribution reports an analysis of an \\

Hans-hellmut Nagel

1983-01-01

32

Displacement fields from point cloud data: Application of particle imaging velocimetry to landslide geodesy  

NASA Astrophysics Data System (ADS)

Acquiring spatially continuous ground-surface displacement fields from Terrestrial Laser Scanners (TLS) will allow better understanding of the physical processes governing landslide motion at detailed spatial and temporal scales. Problems arise, however, when estimating continuous displacement fields from TLS point-clouds because reflecting points from sequential scans of moving ground are not defined uniquely, thus repeat TLS surveys typically do not track individual reflectors. Here, we implemented the cross-correlation-based Particle Image Velocimetry (PIV) method to derive a surface deformation field using TLS point-cloud data. We estimated associated errors using the shape of the cross-correlation function and tested the method's performance with synthetic displacements applied to a TLS point cloud. We applied the method to the toe of the episodically active Cleveland Corral Landslide in northern California using TLS data acquired in June 2005-January 2007 and January-May 2010. Estimated displacements ranged from decimeters to several meters and they agreed well with independent measurements at better than 9% root mean squared (RMS) error. For each of the time periods, the method provided a smooth, nearly continuous displacement field that coincides with independently mapped boundaries of the slide and permits further kinematic and mechanical inference. For the 2010 data set, for instance, the PIV-derived displacement field identified a diffuse zone of displacement that preceded by over a month the development of a new lateral shear zone. Additionally, the upslope and downslope displacement gradients delineated by the dense PIV field elucidated the non-rigid behavior of the slide.

Aryal, Arjun; Brooks, Benjamin A.; Reid, Mark E.; Bawden, Gerald W.; Pawlak, Geno R.

2012-03-01

33

TRANSVERSE EFFECTS DUE TO RANDOM DISPLACEMENT OF RESISTIVE WALL SEGMENTS AND FOCUSING ELEMENTS  

SciTech Connect

In this paper, we study the single bunch transverse beam dynamics in the presence of random displacements of resistive wall segments and focusing elements. Analytical formulas are obtained for long-range resistive wall wake, together with numerical results for short-range resistive wall wake. The results are applied to the LCLS project and some other proposed accelerators.

Jean Delayen; Juhao Wu

2007-06-18

34

Evaluation of Displacement and Pore Pressure change Due to the Injections of Fluid in Geological Formations  

Microsoft Academic Search

Cap rock plays an important role in the geological sequestration of carbon dioxide capture and storage. It indicates the effectiveness of the storage formation controls the leakance of carbon dioxide and serves the need for geological repair and restoration. In this study, two analytical solutions based on the poroelastic theory were presented to evaluate the displacement and pore pressure change

K. Hsu; C. Chang

2010-01-01

35

Macroscopic superposition and entanglement for displaced thermal fields induced by a single atom  

SciTech Connect

We show that a cavity field can evolve from an initial displaced mixed thermal state to a macroscopic superpositions of displaced thermal states via resonant interaction with a two-level atom. As a macroscopic system (meter) is really in a mixed state before coupling with the microscopic system at some temperature, our result is important for studying the quantum measurement problem and decoherence under real conditions. For the two-mode case, entanglement of displaced thermal states between the modes can be obtained.

Zheng, Shi-Biao [Department of Electronic Science and Applied Physics, Fuzhou University, Fuzhou 350002 (China)

2007-03-15

36

On the derivation of coseismic displacement fields using differential radar interferometry: The Landers earthquake  

Microsoft Academic Search

We present a map of the coseimic displacement field resulting from the Landers, California, June 28, 1992, earthquake derived using data acquired from an orbiting high-resolution radar system. We achieve results more accurate than previous space studies and similar in accuracy to those obtained by conventional field survey techniques. Data from the ERS 1 synthetic aperture radar instrument acquired in

Howard A. Zebker; Paul A. Rosen; Richard M. Goldstein; Andrew Gabriel; Charles L. Werner

1994-01-01

37

Application of dynamic displacement current for diagnostics of subnanosecond breakdowns in an inhomogeneous electric field  

NASA Astrophysics Data System (ADS)

The breakdown of different air gaps at high overvoltages in an inhomogeneous electric field was investigated with a time resolution of up to 100 ps. Dynamic displacement current was used for diagnostics of ionization processes between the ionization wave front and a plane anode. It is demonstrated that during the generation of a supershort avalanche electron beam (SAEB) with amplitudes of ~10 A and more, conductivity in the air gaps at the breakdown stage is ensured by the ionization wave, whose front propagates from the electrode of small curvature radius, and by the dynamic displacement current between the ionization wave front and the plane electrode. The amplitude of the dynamic displacement current measured by a current shunt is 100 times greater than the SAEB. It is shown that with small gaps and with a large cathode diameter, the amplitude of the dynamic displacement current during a subnanosecond rise time of applied pulse voltage can be higher than 4 kA.

Shao, Tao; Tarasenko, Victor F.; Zhang, Cheng; Burachenko, Alexandr G.; Rybka, Dmitry V.; Kostyrya, Igor'D.; Lomaev, Mikhail I.; Baksht, Evgeni Kh.; Yan, Ping

2013-05-01

38

Application of dynamic displacement current for diagnostics of subnanosecond breakdowns in an inhomogeneous electric field.  

PubMed

The breakdown of different air gaps at high overvoltages in an inhomogeneous electric field was investigated with a time resolution of up to 100 ps. Dynamic displacement current was used for diagnostics of ionization processes between the ionization wave front and a plane anode. It is demonstrated that during the generation of a supershort avalanche electron beam (SAEB) with amplitudes of ~10 A and more, conductivity in the air gaps at the breakdown stage is ensured by the ionization wave, whose front propagates from the electrode of small curvature radius, and by the dynamic displacement current between the ionization wave front and the plane electrode. The amplitude of the dynamic displacement current measured by a current shunt is 100 times greater than the SAEB. It is shown that with small gaps and with a large cathode diameter, the amplitude of the dynamic displacement current during a subnanosecond rise time of applied pulse voltage can be higher than 4 kA. PMID:23742550

Shao, Tao; Tarasenko, Victor F; Zhang, Cheng; Burachenko, Alexandr G; Rybka, Dmitry V; Kostyrya, Igor' D; Lomaev, Mikhail I; Baksht, Evgeni Kh; Yan, Ping

2013-05-01

39

Field Effect on Displacive First-Order Transition in Relaxor Ferroelectrics  

NASA Astrophysics Data System (ADS)

As preliminaries of a microscopic theory for displacive phase transition, the first-order transition is investigated within a phenomenological study that provides a good explanation of experimental results on the electric field dependence and pressure effect in relaxor ferroelectrics. The morphotropic phase boundary (MPB) region in mixed perovskite oxides is described in the same phase diagram corresponding to individual perovskite oxides with successive phase transitions. On the basis of the calculated field-dependent phase transitions, the origin of the MPB is examined in comparison with that in the case of BaTiO3 with the first-order displacive transition.

Matsushita, Eiko; Sugiyama, Kouichi; Nozawa, Kazuki

2012-09-01

40

Particle displacements in the elastic deformation of amorphous materials: Local fluctuations vs. non-affine field  

NASA Astrophysics Data System (ADS)

We study the local disorder in the deformation of amorphous materials by decomposing the particle displacements into a continuous, inhomogeneous field and the corresponding fluctuations. We compare these fields to the commonly used non-affine displacements in an elastically deformed 2D Lennard-Jones glass. Unlike the non-affine field, the fluctuations are very localized, and exhibit a much smaller (and system size independent) correlation length, on the order of a particle diameter, supporting the applicability of the notion of local "defects" to such materials. We propose a scalar "noise" field to characterize the fluctuations, as an additional field for extended continuum models, e.g., to describe the localized irreversible events observed during plastic deformation.

Goldenberg, C.; Tanguy, A.; Barrat, J.-L.

2007-10-01

41

Retaking the Field: The Constitutional Constraints on Federal Legislation That Displaces Consent Decrees  

Microsoft Academic Search

Part I focuses on the provisions implicated when Congress eliminates or modifies the regulatory consent decrees of federal courts—the separation of powers guarantee, the Takings Clause, the Contracts Clause, and the Due Process Clause. Part II examines the Supremacy Clause and Tenth Amendment issues that potentially circumscribe congressional efforts to displace the decrees of state courts. Part III discusses the

Brian M. Hoffstadt

1999-01-01

42

Measuring displacement fields by cross-correlation and a differential technique: experimental validation  

NASA Astrophysics Data System (ADS)

A digital image correlation (DIC) algorithm for displacement measurements combining cross-correlation and a differential technique was validated through a set of experimental tests. These tests consisted of in-plane rigid-body translation and rotation tests, a tensile mechanical test, and a mode I fracture test. The fracture mechanical test, in particular, was intended to assess the accuracy of the method when dealing with discontinuous displacement fields, for which subset-based image correlation methods usually give unreliable results. The proposed algorithm was systematically compared with the Aramis® DIC-2D commercial code by processing the same set of images. When processing images from rigid-body and tensile tests (associated with continuous displacement fields), the two methods provided equivalent results. When processing images from the fracture mechanical test, however, the proposed method obtained a better qualitative description of the discontinuous displacements. Moreover, the proposed method gave a more reliable estimation of both crack length and crack opening displacement of the fractured specimen.©

Xavier, José; Sousa, António M. R.; Morais, José J. L.; Filipe, Vitor M. J.; Vaz, Mario

2012-04-01

43

[Visual field defects due to antiepileptic drugs].  

PubMed

Within the last years several reports concerning visual field defects, associated with antiepileptic drugs, have been published. In addition to antiepileptic drugs several other causes (e.g. retinopathy or chloroquine, phenothiazine etc.) may induce visual field disturbances. Visual field defects have been observed during vigabatrine, tiagabine, gabapentine, diazepam, phenytoine, and carbamazepine treatment. In 13 to 46% visual field defects are reported to be linked with epilepsies. In addition to general population based studies concerning visual field defects and prospective etiological studies in epilepsies, preclinical studies for the examination of the pathomechanism of visual field defects are necessary. PMID:10412701

Stefan, H; Bernatik, J; Knorr, J

1999-06-01

44

Displacement field for an edge dislocation in a layered half-space  

USGS Publications Warehouse

The displacement field for an edge dislocation in an Earth model consisting of a layer welded to a half-space of different material is found in the form of a Fourier integral following the method given by Weeks et al. [1968]. There are four elementary solutions to be considered: the dislocation is either in the half-space or the layer and the Burgers vector is either parallel or perpendicular to the layer. A general two-dimensional solution for a dip-slip faulting or dike injection (arbitrary dip) can be constructed from a superposition of these elementary solutions. Surface deformations have been calculated for an edge dislocation located at the interface with Burgers vector inclined 0??, 30??, 60??, and 90?? to the interface for the case where the rigidity of the layer is half of that of the half-space and the Poisson ratios are the same. Those displacement fields have been compared to the displacement fields generated by similarly situated edge dislocations in a uniform half-space. The surface displacement field produced by the edge dislocation in the layered half-space is very similar to that produced by an edge dislocation at a different depth in a uniform half-space. In general, a low-modulus (high-modulus) layer causes the half-space equivalent dislocation to appear shallower (deeper) than the actual dislocation in the layered half-space.

Savage, J. C.

1998-01-01

45

Time domain modeling of damping using anelastic displacement fields and fractional calculus  

Microsoft Academic Search

A fractional derivative model of linear viscoelasticity based on the decomposition of the displacement field into an anelastic part and elastic part is developed. The evolution equation for the anelastic part is then a differential equation of fractional order in time. By using a fractional order evolution equation for the anelastic strain the present model becomes very flexible for describing

Mikael Enelund; George A. Lesieutre

1999-01-01

46

Construction of a high-resolution moiré interferometer for investigating microstructural displacement fields in materials.  

PubMed

A high-magnification moiré interferometer has been constructed with a spatial resolution of the order of 1 microm to measure the local in-plane displacement field associated with a material's microstructure. Laser illumination passes through phase-stepping optics and is delivered to the microscope head by polarization-preserving single-mode optical fibres. The head itself is a compact unit consisting of collimating optics, an objective lens and a charge coupled device (CCD) camera. Thin-phase gratings are cast onto the sample surface with a compliant epoxy resin and coated with ca. 5 nm of gold to enhance the fringe contrast and reduce speckle noise. By switching between the laser illumination and white-light illumination, the underlying microstructure is viewed in exact registration with the measured displacement fields. The application of the instrument is illustrated here by visualization of displacement fields in polymer-bonded explosives (PBXs) during deformation to failure. PBXs are highly filled polymers consisting of up to 95% by weight crystalline explosive bound in a variety of polymeric binders. The mechanical properties of PBXs are highly dependent on the microstructure, and moiré interferometry is an ideal tool for investigating the relationship between the 1-100 microm sized crystals and the displacement fields. Methods such as this are required if computer models of inhomogeneous materials are to be accurately validated. PMID:12804287

Goldrein, H T; Rae, P J; Palmer, S J P; Field, J E

2002-05-15

47

Seismic displacements of landfills and deformation of geosynthetics due to base sliding  

Microsoft Academic Search

Seismic design of waste landfills has been a subject of intense research over the past two decades, primarily due to the severe environmental impact of a potential failure. The majority of the related studies have been focused on the stability assessment of landfills utilizing permanent deformation methods. However, previous investigations have not fully addressed the impact of the composite liner

Varvara Zania; Yiannis Tsompanakis; Prodromos N. Psarropoulos

2010-01-01

48

Generation displacement, power losses and emissions reduction due to solar thermal water heaters  

Microsoft Academic Search

A big portion of the electricity generated is wasted in the form of losses. Losses occur at all levels of the power system- generation, transmission, and distribution. However, at least 75% of the total system losses occur in the distribution system. We present a study of real power losses reduction at the distribution level due to the use of solar

J. Jimenez-Gonzalez; A. A. Irizarry-Rivera

2005-01-01

49

Surface displacement due to degree-1 loading in reference frames realized by imperfect geodetic networks  

Microsoft Academic Search

Load-induced geocenter motion has become a crucial factor for maintaining a terrestrial reference frame (TRF) at submillimeter level in near real-time, and for estimates of the variation of the degree-1 gravity field. Realization of the commonly adopted center of figure (CF) frame requires an infinite number of observation sites uniformly distributed over the Earth's surface. In reality, we can only

M. Fang; B. H. Hager

2009-01-01

50

Ionospheric effects due to electrostatic thundercloud fields  

Microsoft Academic Search

Electrostatic thundercloud fields are shown to heat lower ionospheric electrons significantly under night time conditions. The effect is maximized under conditions of higher altitudes of thundercloud charges, larger magnitudes of these charges, and larger scale heights of ambient conductivity profiles. The lower ionospheric conductivity can be modified as a result of the heating by up to one order of magnitude

Victor P. Pasko; Umran S. Inan; Timothy F. Bell

1998-01-01

51

Mars: a magnetic field due to thermoremanence?  

NASA Astrophysics Data System (ADS)

Presently available magnetic field data suggest a dipole moment of Mars of less than 10 -4 times the Earth's dipole moment. Presumably, Mars does not have an active dynamo at present which could give rise to a significant magnetic field. Nevertheless, the presently available data do not rule out a minor intrinsic field which may originate from a magnetized lithosphere. The objective of this study is to examine how much magnetization the Martian lithosphere could have acquired in the presence of an internal dynamo in early Martian history. Two models are presented: the first one assumes a laterally homogeneous lithosphere with a globally uniform thickness; the second model takes a possible dichotomy of the Martian lithosphere into account, which is assumed to be two to three times thicker in the southern hemisphere than in the northern hemisphere. The gradual cooling of the lithosphere below the Curie temperature is reproduced by a multilayer model. Curie isotherm motion with time and the dipole moment of the dynamo field are calculated from a thermal evolution model. For simplicity, the magnetic properties of the lithosphere are parameterized by its iron content. In the homogeneous case, the magnetostatic boundary value problem is solved exactly; in addition, an approximate solution is presented which is applicable with the dichotomy model. Using either method, the demagnetizing field in the separate layers mainly leads to the resulting remanent dipole moment. The remanent dipole moment is found to depend approximately linearly on the Curie isotherm depth and approximately quadratically on the iron content of the lithosphere. To reproduce the upper limit of the dipole moment derived from the Phobos mission (˜10 18 Am 2), a mean depth of 150 to 200 km for the Curie isotherm and a free iron content ranging from 5 to 6 vol.% are needed. The mean surface field may be less than 10 nT for both the homogeneous and the dichotomy model. The latter model yields a marked difference between the northern and southern hemisphere, with a pronounced anomaly at the dichotomy boundary.

Leweling, Martin; Spohn, Tilman

1997-11-01

52

Revolving-Field Analysis of T- and L-Connected Capacitor Motors with Arbitrarily Displaced Windings  

Microsoft Academic Search

Performance equations on T- and L-connected tapped-winding capacitor motors with both the extra-main and the auxiliary windings arranged arbitrarily in space from the main winding are presented in this paper, using the revolving-field theory. Also shown is the fact that these general equations can be employed to yield performance on conventional T- and L-connected capacitor motors. By displacing the windings

Bhag Guru

1979-01-01

53

Numerical simulation of displacement field of solidification process for investment casting  

Microsoft Academic Search

Computer simulation of the solidification process is used widely in the design of the mould and the die configuration. In this work, a simple and efficient methodology is proposed for the numerical simulation of displacement field for investment casting. The heat-transfer behavior and the time-dependent heat transfer coefficient between a casting and mould are investigated by inverse heat-conduction analysis, so

Yiwei Dong; Kun Bu; Dinghua Zhang

2008-01-01

54

Evaluation Of The Compressive Response Of Notched Composite Panels Using A Full-Field Displacement  

Microsoft Academic Search

An experimental and analytical evaluation of the compressive response of two composite, notched stiflened panels representativeof primar T composite wing structure is presented. A three-dimensional full-field image correlation technique isused to measure all three displacement components over global and local areas of the test panels. Point-wise and full-fieldresults obtained using the image correlation technique are presented and compared to experimental

David M. Mcgowan; Damodar R. Ambur; T. Glen Hanna; Stephen R. Mcneill

55

HEMP - hand-displacement-based pseudo-haptics: A study of a force field application and a behavioural analysis  

Microsoft Academic Search

This paper introduces a novel pseudo-haptic approach called HEMP—Hand-displacEMent-based Pseudo-haptics. The main idea behind HEMP is to provide haptic-like sensations by dynamically displacing the visual representation of the user's hand. This paper studies the possible application of HEMP to the simulation of force fields (FFs). The proposed hardware solution for simulating the hand displacement is based on an augmented reality

Andreas Pusch; Olivier Martin; Sabine Coquillart

2009-01-01

56

Contribution of nuclear displacements to the static polarizability of molecules in an external electric field: Application to fluorinated fullerenes C{sub 60}F{sub n}  

SciTech Connect

In molecules with ionic contributions to the binding, the contribution of nuclear displacements (due to the external field) to the static polarizability can be decisive. Using the finite field method, we optimized the structure with and without a finite external electric field by a total energy minimization and we calculated the polarizability from the induced dipole moment. In C{sub 60}F{sub n}, fluorination mostly increases the polarizability. Only for n=2 and 18, where the molecule without an external field has a very large dipole moment, does fluorination decrease it. For large n (n=20, 36, and 48), the polarizability per added F atom due to nuclear displacements is increased by a factor of about 2. The validity of the additivity model has been discussed.

Zagorodniy, K.; Taut, M.; Hermann, H. [Leibniz Institute for Solid State and Materials Research, IFW Dresden, P.O. Box 270016, 01171 Dresden (Germany)

2006-05-15

57

Surface displacement due to degree-1 loading in reference frames realized by imperfect geodetic networks  

NASA Astrophysics Data System (ADS)

Load-induced geocenter motion has become a crucial factor for maintaining a terrestrial reference frame (TRF) at submillimeter level in near real-time, and for estimates of the variation of the degree-1 gravity field. Realization of the commonly adopted center of figure (CF) frame requires an infinite number of observation sites uniformly distributed over the Earth’s surface. In reality, we can only approximate the idealized CF frame by using a finite number of irregularly distributed sites. We call this approximation the center of network (CN) frame. Irregularities in site distribution alias the response of the spherical Earth to degree-1 surface loading. We develop a new theory to cope with this situation. We show that load-induced geocenter motions in a general CN frame formally split the degenerate degree-1 load Love numbers into harmonic-order dependent, (m = -1, 0, 1). To eliminate the unknown variables contained in their formal expressions, we extend the split-load Love numbers into degree-1 Love matrices, H1, L1, and K1. Useful split-load Love numbers can be defined in what we call the principal frame of loading, analogous to the principal frame of stress. The artificial aliasing caused by irregular site distributions is quantified and clearly visualized in those well-defined split load Love numbers in the principle CN frame. In a detailed case study, we consider a realistic CN frame and its partial decompositions, CNh and CNl, maintained by 99 IGS reference sites. The two partials are found much less aliased then the complete CN frame. Based on synthetic true geocenter motion generated from MIT’s OGCM and the GLDAS hydrology model, a simulated GPS inversion is performed under the scheme of purposely misusing the CN frame as an idealized center of figure frame. Significant biases, by a factor ~2, are produced in the direction, confirming the conjecture that the exceptionally large components obtained from previous inversions of real data are indeed spurious.

Fang, M.; Hager, B. H.

2009-12-01

58

The tidal displacement field at Earth's surface determined using global GPS observations  

NASA Astrophysics Data System (ADS)

We investigate the 3-D tidal displacement field on Earth's surface recorded globally by 456 continuous global positioning system (GPS) stations of IGS spanning 1996-2011, for eight principal diurnal and semidiurnal tidal constituents. In-phase and quadrature amplitudes of the residual tidal displacements, after removal of an a priori body tide model, are estimated using the precise point positioning (PPP) technique on the daily GPS data; the resultant daily estimates are combined to derive final estimates for each tide at each station. The results are compared with the predictions of eight recent global ocean tide models, separately for coastal (307) and inland (149) stations. We show that GPS can provide tidal displacement estimates accurate to the level of 0.12 mm (horizontal) and 0.24 mm (vertical) for the lunar-only constituents (M2, N2, O1, and Q1) and less favorably for solar-related tidal constituents (S2, K2, K1, and P1), although improved by ambiguity resolution. Most recent ocean tide models fit the GPS estimates equally well on the global scale but do not agree well between them in certain coastal areas, especially for the vertical displacements, suggesting the existence of model uncertainties near shallow seas. The tidal residuals for the inland stations after removing both body tides and ocean tidal loading (OTL) furthermore show clear continental-scale spatial coherence, implying deficiencies of the a priori body tide modeling in catching lateral heterogeneity in elastic as well as inelastic properties in the Earth's deep interior. We assert that the GPS tidal displacement estimates now achieve sufficient accuracy to potentially provide constraints on the Earth's structure.

Yuan, Linguo; Chao, Benjamin Fong; Ding, Xiaoli; Zhong, Ping

2013-05-01

59

Probabilistic Fault Displacement Hazard Assessment For Pipelines, Mad Dog and Atlantis Field Developments, Deepwater Gulf of Mexico  

NASA Astrophysics Data System (ADS)

Seafloor faults having strong geomorphic expression and evidence for late Quaternary activity (i.e. < ~150,000 years) are common geologic features associated with the Sigsbee Escarpment. Waterbottom maps derived from exploration 3D multichannel seismic data provided an early indication that several zones of seafloor faults are in the vicinity of the Mad Dog and Atlantis prospect areas. As part of the site investigation activities for field development BP initiated a study to characterize the potential hazard due to fault displacement. The fault displacement hazard study consists of five components: 1) a site-wide structural geologic characterization of the style and origin of active faulting and fault-related deformation; 2) development of a late Quaternary stratigraphic model to evaluate the history, recency, and rate of fault activity at the site; 3) detailed characterization of faulting within limited study areas designated to capture fault behavior in areas of potential facilities development; 4) a general description of the relationship between Quaternary active faulting and slope failure processes within the field area; and 5) a probabilistic fault displacement hazard analysis (PFDHA) of the potential for fault rupture within the designated study areas that relates annual frequency of recurrence of faulting events to the size of the event. Changes in the style and origin of faulting and deformation of shallow (suprasalt) sediment across the individual field areas primarily is due to differences in the depth, geometry, and movement history of the underlying Sigsbee Salt Nappe. These relationships and the resulting geologic model for structural evolution of the suprasalt section has been used effectively to assess the site-wide geohazards not only for faulting, but also indirectly for slope failure and mass-gravity flows. Hazard from potential seafloor offset at fault crossings is judged to be moderate to low. Fault offsets of the shallowest horizons (less than 15 thousand years old) are typically less than ten meters to several tens of meters. Fault slip rates are on the order of tenths to several tens of meters-per-thousand-years (m/kyr, also millimeters-per-year, or mm/yr), with most values in the range of 2-10 m/kyr. Similarly, the probabilistic annual recurrence of 1-meter events is typically less than 10-3. These studies demonstrate that the presence of potentially active faults does not preclude safe development of seafloor facilities. To evaluate risk associated with potential seafloor faulting, integrated hazard studies can and should be conducted in the early stages of project development, with an underlying intent to understand the causative processes and quantitatively and explicitly evaluate the locations, magnitude and recurrence potential of displacement events.

Angell, M.; Hanson, K.; Swan, F.; Youngs, R.; Abramson, H.

2004-12-01

60

Cosmic electromagnetic fields due to perturbations in the gravitational field  

NASA Astrophysics Data System (ADS)

We use nonlinear gauge-invariant perturbation theory to study the interaction of an inflation produced seed magnetic field with density and gravitational wave perturbations in an almost Friedmann-Lemaître-Robertson-Walker spacetime with zero spatial curvature. We compare the effects of this coupling under the assumptions of poor conductivity, perfect conductivity and the case where the electric field is sourced via the coupling of velocity perturbations to the seed field in the ideal magnetohydrodynamic regime, thus generalizing, improving on and correcting previous results. We solve our equations for long wavelength limits and numerically integrate the resulting equations to generate power spectra for the electromagnetic field variables, showing where the modes cross the horizon. We find that the interaction can seed electric fields with nonzero curl and that the curl of the electric field dominates the power spectrum on small scales, in agreement with previous arguments.

Mongwane, Bishop; Dunsby, Peter K. S.; Osano, Bob

2012-10-01

61

The Contribution of Coseismic Displacements due to Splay Faults Into the Local Wavefield of the 1964 Alaska Tsunami  

NASA Astrophysics Data System (ADS)

The Alaska Earthquake Information Center conducts tsunami inundation mapping for coastal communities in Alaska. For many locations in the Gulf of Alaska, the 1964 tsunami generated by the Mw9.2 Great Alaska earthquake may be the worst-case tsunami scenario. We use the 1964 tsunami observations to verify our numerical model of tsunami propagation and runup, therefore it is essential to use an adequate source function of the 1964 earthquake to reduce the level of uncertainty in the modeling results. It was shown that the 1964 co-seismic slip occurred both on the megathrust and crustal splay faults (Plafker, 1969). Plafker (2006) suggested that crustal faults were a major contributor to vertical displacements that generated local tsunami waves. Using eyewitness arrival times of the highest observed waves, he suggested that the initial tsunami wave was higher and closer to the shore, than if it was generated by slip on the megathrust. We conduct a numerical study of two different source functions of the 1964 tsunami to test whether the crustal splay faults had significant effects on local tsunami runup heights and arrival times. The first source function was developed by Johnson et al. (1996) through joint inversion of the far-field tsunami waveforms and geodetic data. The authors did not include crustal faults in the inversion, because the contribution of these faults to the far-field tsunami was negligible. The second is the new coseismic displacement model developed by Suito and Freymueller (2008, submitted). This model extends the Montague Island fault farther along the Kenai Peninsula coast and thus reduces slip on the megathrust in that region. We also use an improved geometry of the Patton Bay fault based on the deep crustal seismic reflection and earthquake data. We propagate tsunami waves generated by both source models across the Pacific Ocean and record wave amplitudes at the locations of the tide gages that recorded the 1964 tsunami. As expected, the two sources produce very similar waveforms in the far field that are also in good agreement with the tide gage records. In order to study the near-field tsunami effects, we will construct embedded telescoping bathymetry grids around tsunami generation area to calculate tsunami arrival times and sea surface heights for both source models of the 1964 earthquake, and use available observation data to verify the model results.

Suleimani, E.; Ruppert, N.; Fisher, M.; West, D.; Hansen, R.

2008-12-01

62

Reconstruction of temperature and displacement fields in satellite sandwich panels based on integrated fiber optic sensors  

NASA Astrophysics Data System (ADS)

Large satellites are equipped with hundreds of sensors for temperature measurement. The large amount of sensors is expensive in terms of integration effort and mass in the case conventional sensors are used. In this article an integrated fiber optic temperature sensor network for the hot spot detection on satellite sandwich panels is introduced. The developed sensor system is integrated with only negligible mechanical impact. It is electro-magnetic immune and decoupled from mechanical loads. In addition to monitoring hotspots, the number and aerial density allows a reliable reconstruction of temperature and displacement fields.

Rapp, Stephan; Baier, Horst

2009-03-01

63

Europa's Alfvén Wing: Shrinking and Displacement by an Induced Magnetic Field  

NASA Astrophysics Data System (ADS)

An Alfvén wing (AW) is created by the interaction of a conducting body with a flowing magnetized plasma. In this presentation we investigate the AW created by the moon Europa in the Jovian magentosphere. During its 7 years of duty the Galileo spacecraft has visited Europa 11 times, out of which 4 flybys were crossing the Europan AW. We have studied the properties of the AW using the magnetic field data, with the moon embedded in different background magnetic field and plasma parameters. We have found the predicted shrinking and displacement of the AW by the induced magentic field in Europa. We also show that the characteristics of the AW can be used to get information about the local plasma parameters.

Volwerk, M.; Khurana, K. K.; Kivelson, M. G.

2004-12-01

64

Monitoring Landslide Displacement Fields at Different Temporal Scale by using GB-INSAR  

NASA Astrophysics Data System (ADS)

The application of SAR Interferometry technique (InSAR) for landslide monitoring, in order to resolve the problems connected to the implementation from the satellite platform, such as spatial resolution, incidence angles, temporal coverages, etc., can benefit from the use of ground-based instrumentation. This work concerns the application of ground-based SAR interferometry (GB-InSAR) to the monitoring of landslides characterized by different kinematics and diverse materials. This implementation has been realized by using the LISA (Linear Synthetic Radar) system developed at the JRC. The test sites, chosen to demonstrate the capabilities of such a technique in operational conditions, are the Ruinon rock slide in Valtellina, the Tessina earth slide in the Italian Dolomites and the Firenzuola rockslide in the Northern Appennines. The presence of independent monitoring systems within these landslides has allowed the radar measures to be validated. The LISA is a SAR system with interferometric capabilities specifically design for field applications. It is composed by a 2.8 m linear rail along which a motorised sled with two antennas is moved in order to obtain the synthetic aperture. The system can operate in the frequency band Ku (l = 1.8 cm) or C (l = 5.6 cm). Coherent SAR processing transforms raw data, acquired by the system, into a SAR images containing for each pixel information regarding the signal phase which depends on the target-sensor distance. Acquiring the data exactly from the same position (zero baseline condition), it is possible to directly relate the phase variations obtained by the interferometric analysis of consecutive couple of images to ground displacements along the line of sight of the radar instrumentations. Otherwise, by acquiring two radar datasets from slightly different positions it is possible to relate the phase variations obtained from the interferometric analysis to the topography of the observed area, providing an accurate DEM of the scene. While the first application allows to continuously follow the short term temporal evolution of the mass movements, the second one permits, by the comparison between interferometric DEM obtained in different periods, to observe the landslide evolution on a longer temporal scale. The application of these approaches to the selected test sites have demonstrated, by means of the comparison with traditionals instrumentations, the excellent precision and accuracy of the new technique. The use of such a technique, providing deformations maps of the studied area, facilitates the interpretation of the movement mechanism. Due to its non-invasive character, the good versatility in terms of suitable mass movement and the very high definition, the technique is well suited to mass movements, especially for those affecting urban area and cultural heritage.

Tarchi, D.; Casagli, N.; Catani, F.; Farina, P.; Leva, D.; Nico, G.

2002-12-01

65

A case of facial deformity due to bilateral developmental maxillary cheek teeth displacement in an adult horse  

PubMed Central

A 7-year-old mare presented with facial deformities associated with oral discomfort and weight loss was found to have bilateral, palatal, developmental displacements of the maxillary 08s, with secondary diastema. Following repulsion of both displaced teeth, the horse regained weight and resumed training. Bony deformities remained visible 9 mo after discharge.

Robert, Mickael P.; Gangl, Monika C.; Lepage, Olivier M.

2010-01-01

66

Extracting tractosemas from a displacement probability field for tractography in DW-MRI.  

PubMed

In this paper we present a novel method for estimating a field of asymmetric spherical functions, dubbed tractosemas, given the intra-voxel displacement probability information. The peaks of tractosemas correspond to directions of distinct fibers, which can have either symmetric or asymmetric local fiber structure. This is in contrast to the existing methods that estimate fiber orientation distributions which are naturally symmetric and therefore cannot model asymmetries such as splaying fibers. We propose a method for extracting tractosemas from a given field of displacement probability iso-surfaces via a diffusion process. The diffusion is performed by minimizing a kernel convolution integral, which leads to an update formula expressed in the convenient form of a discrete kernel convolution. The kernel expresses the probability of diffusion between two neighboring spherical functions and we model it by the product of Gaussian and von Mises distributions. The model is validated via experiments on synthetic and real diffusion-weighted magnetic resonance (DW-MRI) datasets from a rat hippocampus and spinal cord. PMID:18979726

Barmpoutis, Angelos; Vemuri, Baba C; Howland, Dena; Forder, John R

2008-01-01

67

Electric field effects on fluorescence quenching due to electron transfer  

Microsoft Academic Search

The effect of an external electric field on fluorescence quenching due to electron transfer from a photoexcited electron donor to an acceptor has been analyzed theoretically. The model predicts that at weak fields the variation DeltaI(c,F)\\/I(c,0) in the steady-state monomer fluorescence intensity induced by an external electric field is proportional to the square of the field strength F and to

Maria Hilczer; Sergey Traytak; M. Tachiya

2001-01-01

68

Plasma Diffusion across a Magnetic Field Due to Thermal Vortices.  

National Technical Information Service (NTIS)

A convergent cross-field diffusion coefficient due to flute-type thermal fluctuations (vortices) is derived, taking into account the nonlinear, orbit-diffusion effect on the dynamic screening of the interaction and the fluctuation spectrum. Because of the...

Y. C. Lee C. S. Liu

1972-01-01

69

Coseismic displacement field of the Wenchuan Ms 8.0 earthquake in 2008 derived using differential radar interferometry  

Microsoft Academic Search

We used the radar data from satellite ALOS\\/PALSAR of Japan and D-InSAR technology to derive the coseismic displacement produced by the Wenchuan, China Ms 8.0 earthquake on 12 May 2008. The result shows that the coseismic displacement primarily concentrated in a near-field range about 100km width on both sides of the Yingxiu-Beichuan fault. The incoherent zone about 250km long and

Chunyan Qu; Xinjian Shan; Guohong Zhang; Xiaogang Song; Guifang Zhang

2010-01-01

70

Applying a Bayesian Approach to Identification of Orthotropic Elastic Constants from Full Field Displacement Measurements  

NASA Astrophysics Data System (ADS)

A major challenge in the identification of material properties is handling different sources of uncertainty in the experiment and the modelling of the experiment for estimating the resulting uncertainty in the identified properties. Numerous improvements in identification methods have provided increasingly accurate estimates of various material properties. However, characterizing the uncertainty in the identified properties is still relatively crude. Different material properties obtained from a single test are not obtained with the same confidence. Typically the highest uncertainty is associated with respect to properties to which the experiment is the most insensitive. In addition, the uncertainty in different properties can be strongly correlated, so that obtaining only variance estimates may be misleading. A possible approach for handling the different sources of uncertainty and estimating the uncertainty in the identified properties is the Bayesian method. This method was introduced in the late 1970s in the context of identification [1] and has been applied since to different problems, notably identification of elastic constants from plate vibration experiments [2]-[4]. The applications of the method to these classical pointwise tests involved only a small number of measurements (typically ten natural frequencies in the previously cited vibration test) which facilitated the application of the Bayesian approach. For identifying elastic constants, full field strain or displacement measurements provide a high number of measured quantities (one measurement per image pixel) and hence a promise of smaller uncertainties in the properties. However, the high number of measurements represents also a major computational challenge in applying the Bayesian approach to full field measurements. To address this challenge we propose an approach based on the proper orthogonal decomposition (POD) of the full fields in order to drastically reduce their dimensionality. POD is based on projecting the full field images on a modal basis, constructed from sample simulations, and which can account for the variations of the full field as the elastic constants and other parameters of interest are varied. The fidelity of the decomposition depends on the number of basis vectors used. Typically even complex fields can be accurately represented with no more than a few dozen modes and for our problem we showed that only four or five modes are sufficient [5]. To further reduce the computational cost of the Bayesian approach we use response surface approximations of the POD coefficients of the fields. We show that 3rd degree polynomial response surface approximations provide a satisfying accuracy. The combination of POD decomposition and response surface methodology allows to bring down the computational time of the Bayesian identification to a few days. The proposed approach is applied to Moiré interferometry full field displacement measurements from a traction experiment on a plate with a hole. The laminate with a layup of [45,- 45,0]s is made out of a Toray® T800/3631 graphite/epoxy prepreg. The measured displacement maps are provided in Figure 1. The mean values of the identified properties joint probability density function are in agreement with previous identifications carried out on the same material. Furthermore the probability density function also provides the coefficient of variation with which the properties are identified as well as the correlations between the various properties. We find that while the longitudinal Young’s modulus is identified with good accuracy (low standard deviation), the Poisson’s ration is identified with much higher uncertainty. Several of the properties are also found to be correlated. The identified uncertainty structure of the elastic constants (i.e. variance co-variance matrix) has potential benefits to reliability analyses, by allowing a more accurate description of the input uncertainty. An additional advantage of the Bayesian approach is that it provides a natural way (in the form of the prior probab

Gogu, C.; Yin, W.; Haftka, R.; Ifju, P.; Molimard, J.; Le Riche, R.; Vautrin, A.

2010-06-01

71

Field due to a dipole in a polarisable molecular lattice  

Microsoft Academic Search

The effective electric field due to a permanent dipole in an arbitrary Bravais lattice of polarisable non-polar molecules is expressed exactly, taking account of the different polarisability of the polar guest molecule. The asymptotic behaviour of the field at large distances from the dipole is evaluated. An interpretation is offered for the rescaled dipole moment required to give agreement with

R. W. Munn; I. Eisenstein

1983-01-01

72

Some thoughts on error-contributions to reconstruct 3D coseismic displacement field using the model of combining multiple independent InSAR  

NASA Astrophysics Data System (ADS)

Interferometric Synthetic Aperture Radar (InSAR) has proved an immensely powerful tool in studying earthquakes with millimetre-scale accuracy at a high spatial resolution. However, each interferogram records only the component of displacement in the direction of the satellite line of sight (LOS). Thus previous InSAR studies of displacement due to earthquakes were generally limited to one or two components of the surface displacement field. Three- dimensional (3D) surface displacement maps can provide a more comprehensive understanding of source geometry associated with earthquake. By combining interferograms from multiple look angles, it is possible to constrain the three-dimensional components of displacement [Jung et al., 2011; Wright, et al., 2004; Hong et al., 2010]. In this work, we take 2008 Gaize Ms6.9 earthquake (Tibet) for example, derive LOS surface displacement from several paths of ENVISAT ASAR images (Image mode: Track 348, descending pass; Track 341, 427, and 155, ascending pass. ScanSAR mode: Track 341, 112, 155, and 384, ascending pass), and reconstruct the 3D coseismic displacement field with the model named multiple independent InSAR with different viewing angles. Because it is difficult to distinguish tectonic signal from phase noise (eg. orbital errors, atmospheric errors, and unwrapping errors), these error-contributions may be propagated to the 3D coseismic components (vertical, north, east). In addition, for ENVISAT ASAR, it is worth notice that the radar antenna is fixed with respect to the current satellite, which may lead to different LOS observations with nearly identical viewing angles in parallel passes. Thus, when inverting 3D components with least square solution, InSAR observation errors may be magnified by the ill-conditioned system of equations in the solution. Although the ill-conditioned system of equations may result in bad solution, some InSAR observation errors can be detected by the system. In our study, we will introduce the condition number (cond) of coefficient matrix to evaluate the condition of equation set. Our purposes are: 1) to find above which condition number (critical value) we can detect the observation errors from the equation set; 2) to comprehensive understand how the accuracies of 3D components are affected by ill-conditioned system. According to the answers of these two questions, some optimized algorithm may be proposed to improve the accuracies of reconstructing 3D coseismic displacement field.

Liu, Bin; Zhang, Jingfa; Luo, Yi

2012-07-01

73

Quantitative study of laser induced material removal mechanisms in aluminium: contributions due to vaporization, melt displacement and ejection  

Microsoft Academic Search

We report the results of a threefold investigation of nanosecond laser ablation of aluminium that permits us to isolate the relative contributions to material removal associated with vaporization, melt displacement and melt ejection. The analytical methods employed and results will be discussed.

M. J. Withford; J. M. Fishburn; D. W. Coutts; J. A. Piper

2005-01-01

74

Surface displacement field at Terceira island deduced from repeated GPS measurements  

NASA Astrophysics Data System (ADS)

We present the results of six GPS (Global Positioning System) campaigns held in Terceira Island (Azores) between 1999 and 2006 for a group of 17 stations, to estimate the surface displacement field induced by the Eurasian-Nubian interplate motion, and their relationship with the rifting along Terceira Rift and volcanic processes at the island scale. We show that the whole island mainly behaves like a rigid body which absolute motion is closer to Eurasia. The magnitude of the computed intra-island horizontal deformation field (difference between the individual site velocities and the mean rigid-body motion) is still below the observation accuracy, and so cannot be directly related with local processes. We also show that the island is globally subsiding with an average rate close to 1 mm/yr, as it moves to the NE away from the Terceira Rift, mostly attached to the Eurasian plate. The high subsidence rate can be the result of the volcanic processes that shaped the Serreta ridge, NW of Terceira.

Miranda, J. M.; Navarro, A.; Catalão, J.; Fernandes, R. M. S.

2012-03-01

75

Habitat partitioning and competitive displacement in cattails (Typha): experimental field studies  

Microsoft Academic Search

A conspicuous feature of many plant communities that is often considered evidence of competitive displacement is the segregation of species along a habitat gradient. The extent of competitive displacement is examined in a recently established association of cattails (Typha latifolia L. and T. angustifolia L.). To accomplish this, potential and realized distributions of these two species were compared along a

James B. Grace; Robert G. Wetzel

1981-01-01

76

Faraday Rotation Measure Due to the Intergalactic Magnetic Field  

Microsoft Academic Search

Studying the nature and origin of the intergalactic magnetic field (IGMF) is an outstanding problem of cosmology. Measuring Faraday rotation would be a promising method to explore the IGMF in the large-scale structure (LSS) of the universe. We investigated the Faraday rotation measure (RM) due to the IGMF in filaments of galaxies using simulations for cosmological structure formation. We employed

Takuya Akahori; Dongsu Ryu

2010-01-01

77

Alignment of atmospheric mineral dust due to electric field  

Microsoft Academic Search

Optical polarimetry observations on La Palma, Canary Islands, during a Saharan dust episode show dichroic extinction consistent with the presence of vertically aligned particles in the atmosphere. Modelling of the extinction together with particle orientation indicates that the alignment could have been due to an electric field of the order of 2 kV\\/m. Two alternative mechanisms for the origin of

Z. Ulanowski; J. Bailey; P. W. Lucas; J. H. Hough; E. Hirst

2007-01-01

78

Computation of full-field displacements in a scaffold implant using digital volume correlation and finite element analysis.  

PubMed

Measurements of three-dimensional displacements in a scaffold implant under uniaxial compression have been obtained by two digital volume correlation (DVC) methods, and compared with those obtained from micro-finite element models. The DVC methods were based on two approaches, a local approach which registers independent small volumes and yields discontinuous displacement fields; and a global approach where the registration is performed on the whole volume of interest, leading to continuous displacement fields. A customised mini-compression device was used to perform in situ step-wise compression of the scaffold within a micro-computed tomography (?CT) chamber, and the data were collected at steps of interest. Displacement uncertainties, ranging from 0.006 to 0.02 voxel (i.e. 0.12-0.4 ?m), with a strain uncertainty between 60 and 600 ??, were obtained with a spatial resolution of 32 voxels using both approaches, although the global approach has lower systematic errors. Reduced displacement and strain uncertainties may be obtained using the global approach by increasing the element size; and using the local approach by increasing the number of intermediary sub-volumes. Good agreements between the results from the DVC measurements and the FE simulations were obtained in the primary loading direction as well as in the lateral directions. This study demonstrates that volumetric strain measurements can be obtained successfully using DVC, which may be a useful tool to investigate mechanical behaviour of porous implants. PMID:23473631

Madi, K; Tozzi, G; Zhang, Q H; Tong, J; Cossey, A; Au, A; Hollis, D; Hild, F

2013-03-06

79

Mean Cross-Field Displacement of Magnetic Field Lines in Slow Solar Wind: A Confirmation of the Supradiffusion Predicted by the Generalized Quasilinear Theory  

Microsoft Academic Search

A quantitative comparison of the magnetic field-line mean cross-field displacements predicted by the generalized quasilinear theory and of those deduced from Helios 2 in situ measurements is presented for the quiet slow solar wind (SW) at 0.3 and 1 AU. While the supradiffusivity of the magnetic field lines, X2~(Deltaz)mu with 2>=mu>1, is confirmed on all field-aligned scales Deltaz<0.1 AU, the

B. R. Ragot

2006-01-01

80

Analysis of the lateral displacement and optical path difference in wide-field-of-view polarization interference imaging spectrometer  

Microsoft Academic Search

The mechanism of beam splitting and principle of wide-field-of-view compensation of modified Savart polariscope in the wide-field-of-view polarization interference imaging spectrometer (WPIIS) are analyzed and discussed. Formulas for the lateral displacement and optical path difference (OPD) produced by the modified Savart polariscope are derived by ray-tracing method. The theoretical and practical guidance is thereby provided for the study, design, modulation,

Lei Wu; Chunmin Zhang; Baochang Zhao

2007-01-01

81

Simultaneous Atomic Force Microscope and Quartz Crystal Microbalance Measurements: Interactions and Displacement Field of a Quartz Crystal Microbalance  

NASA Astrophysics Data System (ADS)

We analyze the interaction of two instruments often used in material science analysis, the atomic force microscope (AFM) and the quartz crystal microbalance (QCM), here combined in a single instrument for simultaneous measurements on a single sample. We show, using finite element analysis, that the in-plane displacement of a QCM oscillating in liquid with a quality factor of 2000 is 2 nm. The out-of-plane displacement is about one tenth of the in-plane displacement. This latter effect, due to the finite size of the electrodes, results in longitudinal acoustic waves launched in the liquid surrounding the QCM. If bounced against an obstacle, in our case the AFM cantilever holder, these longitudinal waves create standing wave patterns which cause frequency fluctuations of the resonator when it is moved, and thus decrease the QCM sensitivity.

Friedt, J.-M.; Choi, K. H.; Francis, L.; Campitelli, A.

2002-06-01

82

Destructive interferences between diffuse scatterings due to disorder and displacive modulation (X-ray ``white line" effect)  

NASA Astrophysics Data System (ADS)

In the solid solutions of charge transfer salts of the TTF-TCNQ family, a new diffraction effect is observed. The X-ray patterns of such materials show a broad diffuse scattering on which fine “white” diffuse lines at {Q} + 2 {k}_f are observed, whereas at {Q} - 2 {k}_f the diffuse scattering has the usual aspect. We propose a simple interpretation of this +2 {k}_f/ - 2 {k}_f asymmetry of intensity by a coupling in quadrature between a displacement wave and a composition wave of same wave vector. As the effect originates from a coherence between substitutional disorder and the displacement waves, we perform a calculation of the diffracted intensity to first order in displacement, for a one-dimensional alloy in which all the impurities pin a lattice distortion of wave vector 2 {k}_f, with the same phase. We emphasize the three relevant parameters of the calculations : the difference of structure factors of the substituted entities, the phase of the displacement wave with respect to the impurity and its polarization. We then propose that the white lines experimentally observed in (HMTTF){0.05} (HMTSF){0.95}-TCNQ, originate from the 2 {k}_f distortions induced by charge oscillations around the substituted HMTTF molecules on the donor stacks. Dans des solutions solides de sels à transfert de charge de la famille TTF-TCNQ un effet de diffraction original est observé. Les figures de diffraction de tels matériaux font apparaître de larges diffusions diffuses sur lesquelles on observe de fines lignes diffuses “blanches" en {Q} + 2 {k}_f, alors qu'en {Q} - 2 {k}_f on retrouve l'aspect habituel des lignes noires. Nous proposons une interprétation simple de cette asymétrie d'intensité +2 {k}_f/ - 2 {k}_f en couplant en quadrature une onde de déplacement et une onde de composition de même vecteur d'onde. La cohérence entre le désordre de substitution et le déplacement étant à l'origine de l'effet, nous effectuons ensuite un calcul de l'intensité diffusée au premier ordre en déplacement pour un modèle d'alliage unidimensionnel dans lequel toutes les impuretés accrochent une distorsion de réseau à 2 k f, avec la même phase. Ces résultats nous permettent de mettre en évidence les trois paramètres pertinents du problème : la différence entre les facteurs de structure des entités substituées, la phase de l'onde accrochée par rapport à l'impureté et sa polarisation. Nous proposons que les lignes blanches observées expérimentalement dans (HMTTF){0,05} (HMTSF){0,95}-TCNQ résultent des distorsions de réseau couplées aux oscillations de charge induites par des impuretés sur les chaînes donneuses.

Ravy, S.; Pouget, J. P.; Comes, R.

1992-06-01

83

A fingerprint method for the rapid determination of earthquake displacement fields in support of tsunami early warning  

NASA Astrophysics Data System (ADS)

Low latency knowledge of the displacement field associated with a large earthquake is invaluable for estimates of the tsunami potential, the prediction of tsunami propagation, and ultimately reliable early warning. We have developed a fingerprint method for the near-real time determination of the displacement field of earthquakes observed by GPS networks. The fingerprint module is designed as a part of a prototype system for tsunami early warning, and in this system, the output of the fingerprint module feeds into a module for tsunami propagation modeling. In a fault database, fault systems are parameterized and represented by reasonably large elements (order 200 km). For each element, the displacement fields are computed for unit slips and these a priori "fingerprints" are stored in the fault datebase. In general, the slip during an earthquake will have both a normal and a strike-slip component. Therefore, the fingerprints are computed for normal slip and strike slip separately. After a large earthquake, the set of elements participating in the rupture and the slip vector for each element can be determined in a rapid search through the database, in which a large number of reasonable combinations of fingerprints are fitted to low-latency high-resolution GPS time series. Different statistical measures for the fit quality are applied to determine the best-fitting set of elements. The weighted sum of the fingerprints for the identified active elements gives the total displacement field. We have previously validated the method for the 2004 Sumatran earthquake using the data of a sparse GPS network and shown that estimates of the displacement field could be made available within 12 minutes after the start of the rupture. In a time-delayed study, we use this method to investigate the relation between network geometry and minimum magnitude of earthquakes for which reliable determination of the displacement field can be achieved. This study utilizes GPS networks of variable density around several subduction zones, including the Sumatran and Cascadian faults. We also investigate the false-alarm rate as function of earthquake magnitude and network geometry.

Plag, H.-P.; Kremmer, C.; Hammond, W. C.; Blewitt, G.

2009-04-01

84

Biological effects due to weak magnetic field on plants  

NASA Astrophysics Data System (ADS)

Throughout the evolution process, Earth’s magnetic field (MF, about 50 ?T) was a natural component of the environment for living organisms. Biological objects, flying on planned long-term interplanetary missions, would experience much weaker magnetic fields, since galactic MF is known to be 0.1 1 nT. However, the role of weak magnetic fields and their influence on functioning of biological organisms are still insufficiently understood, and is actively studied. Numerous experiments with seedlings of different plant species placed in weak magnetic field have shown that the growth of their primary roots is inhibited during early germination stages in comparison with control. The proliferative activity and cell reproduction in meristem of plant roots are reduced in weak magnetic field. Cell reproductive cycle slows down due to the expansion of G1 phase in many plant species (and of G2 phase in flax and lentil roots), while other phases of cell cycle remain relatively stabile. In plant cells exposed to weak magnetic field, the functional activity of genome at early pre-replicate period is shown to decrease. Weak magnetic field causes intensification of protein synthesis and disintegration in plant roots. At ultrastructural level, changes in distribution of condensed chromatin and nucleolus compactization in nuclei, noticeable accumulation of lipid bodies, development of a lytic compartment (vacuoles, cytosegresomes and paramural bodies), and reduction of phytoferritin in plastids in meristem cells were observed in pea roots exposed to weak magnetic field. Mitochondria were found to be very sensitive to weak magnetic field: their size and relative volume in cells increase, matrix becomes electron-transparent, and cristae reduce. Cytochemical studies indicate that cells of plant roots exposed to weak magnetic field show Ca2+ over-saturation in all organelles and in cytoplasm unlike the control ones. The data presented suggest that prolonged exposures of plants to weak magnetic field may cause different biological effects at the cellular, tissue and organ levels. They may be functionally related to systems that regulate plant metabolism including the intracellular Ca2+ homeostasis. However, our understanding of very complex fundamental mechanisms and sites of interactions between weak magnetic fields and biological systems is still incomplete and still deserve strong research efforts.

Belyavskaya, N. A.

2004-01-01

85

Faraday Rotation due to Magnetic Fields in the Cosmic Web  

NASA Astrophysics Data System (ADS)

Measuring Faraday rotation would be a promising method to explore magnetic fields in the cosmic web. We investigated the Faraday rotation measure (RM) due to the intergalactic magnetic field (IGMF), using a model IGMF predicted with turbulence dynamo in the cosmic web. The inducement of RM is a random walk process, and the probability distribution of |RM| is log-normal. The root mean square (rms) of RM through a single filament in the local universe is of order ? 1 radian/square-meter. By integrating up to redshift z = 5, the rms of RM though a number of filaments is ? several radian/square-meter. The power spectrum of RM has a broad plateau over angular scales of ? 1 - 0.1 degree with a peak close to ? 0.1 degree. The second-order structure function has a flat profile in angular separations of > 0.2 degree. The RM due to the galactic magnetic fields, even towards the poles, should be as large as the extragalactic RM. We suggest a strategy to separate the extragalactic RM from the galactic RM in observations.

Ryu, Dongsu; Akahori, T.

2012-05-01

86

Holographic attachement for a machine for determing the field of displacements  

NASA Astrophysics Data System (ADS)

The application of holographic methods to mechanical testing on a broad scale is hampered by the necessity of placing the loading device on the plate of the holographic unit. The loading device here must be specially designed. Since the device's stand is in most cases insufficiently rigid, pictures of interference bands are obtained which include information not only on the displacement of the points of the sample's surface during its deformation but also on the rotations and displacements of the sample in the clamps. A holographic attachment developed for a certain test machine to cope with this problem is described.

Seleznev, V. G.

1981-02-01

87

Study of coseimic displacement field of the YUSHU MS 7.1 earthquake derived from Envisat\\/Asar data  

Microsoft Academic Search

We used the radar data from the satellite ENVISAT\\/ASAR of ESA and the differential interferometric synthetic aperture radar (D-InSAR) technology to derive the coseismic displacement field produced by the Yushu, Qinghai Province, China Ms 7.1 earthquake on 14 April 2010. Based on processing SAR data acquired before and after the event by the two-pass method, we obtained the interferometric fringe

Chunyan Qu; Guohong Zhang; Guifang Zhang; Xinjian Shan; Xiaogang Song; Yunhua Liu

2011-01-01

88

Displaced squeezed number states of the phonon field in polar semiconductors  

Microsoft Academic Search

Considering that the Fröhlich continuum model of polarons, in the static approximation, describes the electron-phonon interaction in polar semiconductors, and that the Hamiltonian of the generalized parametric oscillator represents the ion vibrations, we have studied a way of producing phonon-displaced squeezed number states. By the use of the evolution operator method, the exact wave function as well as the probability

S. Baskoutas; A. Jannussis; P. Yianoulis

1996-01-01

89

An asymptotic formula for the displacement field in the presence of small anisotropic elastic inclusions  

Microsoft Academic Search

We derive asymptotic expansions for the displacement at the boundary of a smooth, elastic body in the presence of small inhomogeneities. Both the body and the inclusions are allowed to be anisotropic. This work extends prior work of CapdeBoscq and Vogelius ({\\\\em Math. Modelling Num. Anal.} 37, 2003) for the conductivity case. In particular, we obtain an asymptotic expansion of

Elena Beretta; Eric Bonnetier; Elisa Francini

2011-01-01

90

Studies in space orientation: I. Perception of the upright with displaced visual fields  

Microsoft Academic Search

By requiring the S to look into a tilted mirror scene while his body remains erect, we have essentially a situation where the visual coordinates are displaced while the postural upright remains unchanged  In an experiment with 49 Ss striking evidence was found of the primary importance of visual factors in perception of the upright, and of the secondary role

S. E. Asch; H. A. Witkin

1948-01-01

91

Flexible force sensor measuring change in capacitance due to dielectric oil displacement out of domed polymer into surrounding channels  

Microsoft Academic Search

We propose a flexible capacitive force sensor not having vulnerable electrode on force applied site. It has a polymer domed structure inside which silicone oil is contained. When the force is added, the oil is pushed into surrounding thin channels, where the change in capacitance due to flowed-in dielectric oil is measured between two electrodes on top and bottom surfaces

T. Takahashi; M. Suzuki; S. Iwamoto; S. Aoyagi

2011-01-01

92

Improved Newton-Raphson digital image correlation method for full-field displacement and strain calculation.  

PubMed

The two-dimensional in-plane displacement and strain calculation problem through digital image processing methods has been studied extensively in the past three decades. Out of the various algorithms developed, the Newton-Raphson partial differential correction method performs the best quality wise and is the most widely used in practical applications despite its higher computational cost. The work presented in this paper improves the original algorithm by including adaptive spatial regularization in the minimization process used to obtain the motion data. Results indicate improvements in the strain accuracy for both small and large strains. The improvements become even more significant when employing small displacement and strain window sizes, making the new method highly suitable for situations where the underlying strain data presents both slow and fast spatial variations or contains highly localized discontinuities. PMID:21102673

Cofaru, Corneliu; Philips, Wilfried; Van Paepegem, Wim

2010-11-20

93

Immiscible displacement of oil by water in consolidated porous media due to capillary imbibition under ultrasonic waves.  

PubMed

Numerous studies done in the last four decades have demonstrated that acoustic stimulation may enhance recovery in oil reservoirs. This technology is not only technically feasible, but also serves as an economical, environmentally friendly alternative to currently accepted enhanced oil recovery (EOR) method. It requires low capital expenditure, and yields almost immediate improvement without any additional EOR agents. Despite a vast body of empirical and theoretical support, this method lacks sufficient understanding to make meaningful and consistent engineering predictions. This is in part due to the complex nature of the physical processes involved, as well as due to a shortage of fundamental/experimental research. Much of what the authors believe is happening within acoustically stimulated porous media is speculative and theoretical. This paper focuses on the effects of ultrasound on the interfacial forces between immiscible fluids. Capillary (spontaneous) imbibition of an aqueous phase into oil (or air)-saturated Berea sandstone and Indiana limestone samples experiments were conducted. Solutions of water, brine (15,000 and 150,000 ppm NaCl), anionic surfactant (sodium dodecyl diphenyloxide disulfonate), nonionic surfactant (alcohol ethoxylate) and polymer (xanthan gum) were prepared as the aqueous phase. Both counter-current and co-current geometries were tested. Due to the intrinsically unforced, gentle nature of the process, and their strong dependence on wettability, interfacial tension, viscosity and density, such experiments provide valuable insight into some of the governing mechanisms behind ultrasonic stimulation. PMID:17927413

Hamida, Tarek; Babadagli, Tayfun

2007-09-01

94

Modified field amplification sample injection for micellar electrokinetic chromatography of neutral compounds with amino-substituted cyclodextrin as carrier and 1-adamantanecarboxylate as displacer  

Microsoft Academic Search

A modified field amplification sample injection method was proposed and evaluated by using positively mono charged cyclodextrin (CD) as carrier and 1-adamantanecarboxylate as displacer for on-capillary preconcentration of neutral compounds and improvement of the concentration limit of detection in micellar electrokinetic chromatography. In modified sample injection mode a displacer plug was introduced before sample injection to reduce the length of

Tianlin Wang; Lingling Yuan; Sam F. Y. Li

2003-01-01

95

Biological effects due to weak magnetic fields on plants  

NASA Astrophysics Data System (ADS)

In the evolution process, living organisms have experienced the action of the Earth's magnetic field (MF) that is a natural component of our environment. It is known that a galactic MF induction does not exceed 0.1 nT, since investigations of weak magnetic field (WMF) effects on biological systems have attracted attention of biologists due to planning long-term space flights to other planets where the magnetizing force is near 10-5 Oe. However, the role of WMF and its influence on organisms' functioning are still insufficiently investigated. A large number of experiments with seedlings of different plant species placed in WMF has found that the growth of their primary roots is inhibited during the early terms of germination in comparison with control. The proliferation activity and cell reproduction are reduced in meristem of plant roots under WMF application. The prolongation of total cell reproductive cycle is registered due to the expansion of G phase in1 different plant species as well as of G phase in flax and lentil roots along with2 relative stability of time parameters of other phases of cell cycle. In plant cells exposed to WMF, the decrease in functional activity of genome at early prereplicate period is shown. WMF causes the intensification in the processes of proteins' synthesis and break-up in plant roots. Qualitative and quantitative changes in protein spectrum in growing and differentiated cells of plant roots exposed to WMF are revealed. At ultrastructural level, there are observed such ultrastructural peculiarities as changes in distribution of condensed chromatin and nucleolus compactization in nuclei, noticeable accumulation of lipid bodies, development of a lytic compartment (vacuoles, cytosegresomes and paramural bodies), and reduction of phytoferritin in plastids in meristem cells of pea roots exposed to WMF. Mitochondria are the most sensitive organelle to WMF application: their size and relative volume in cells increase, matrix is electron-transparent, and cristae reduce. Cytochemical studies indicate that cells of plant roots exposed to WMF show the Ca2 + oversaturation both in all organelles and in a hyaloplasm of the cells unlike the control ones. The data presented suggest that prolonged plant exposures to WMF may cause different biological effects at the cellular, tissue and organ level. They may be functionally related to systems that regulate plant metabolism including the intracellular Ca 2 + homeostasis. The understanding of the fundamental mechanisms and sites of interactions between WMF and biological systems are complex and still deserve strong efforts, particular addressed to basic principles of coupling between field energy and biomolecules.

Belyavskaya, N.

96

Young's modulus reconstruction for radio-frequency ablation electrode-induced displacement fields: a feasibility study.  

PubMed

Radio-frequency (RF) ablation is a minimally invasive treatment for tumors in various abdominal organs. It is effective if good tumor localization and intraprocedural monitoring can be done. In this paper, we investigate the feasibility of using an ultrasound-based Young's modulus reconstruction algorithm to image an ablated region whose stiffness is elevated due to tissue coagulation. To obtain controllable tissue deformations for abdominal organs during and/or intermediately after the RF ablation, the proposed modulus imaging method is specifically designed for using tissue deformation fields induced by the RF electrode. We have developed a new scheme under which the reconstruction problem is simplified to a 2-D problem. Based on this scheme, an iterative Young's modulus reconstruction technique with edge-preserving regularization was developed to estimate the Young's modulus distribution. The method was tested in experiments using a tissue-mimicking phantom and on ex vivo bovine liver tissues. Our preliminary results suggest that high contrast modulus images can be successfully reconstructed. In both experiments, the geometries of the reconstructed modulus images of thermal ablation zones match well with the phantom design and the gross pathology image, respectively. PMID:19258195

Jiang, Jingfeng; Varghese, Tomy; Brace, Christopher L; Madsen, Ernest L; Hall, Timothy J; Bharat, Shyam; Hobson, Maritza A; Zagzebski, James A; Lee, Fred T

2009-02-27

97

Study of Eastern Canadian Coastal Site Displacement due to Ocean Tide Loading Using a GPS Network in Atlantic Canada  

NASA Astrophysics Data System (ADS)

The continuously operating GPS stations of The Princess of Acadia project, especially the Coast Guard station in Saint John, New Brunswick and the station Digby in Halifax, Nova Scotia, both of which lie in the proximity of highly turbulent waters of Bay of Fundy, are subjected to perpetual movements due to temporally oceanic water mass surface loading of the lithosphere by the ocean tides. If the affects of ocean tide loading are not taken into consideration they can affect high- accuracy positioning especially in the final solutions for height. It is proposed under this project that ocean tidal loading studies be carried out in the area using atleast 1 year of GPS data with varying data processing sessions. Time series would then be extracted from discrete 24-hour solutions for ocean tide loading studies. Data collection in this regard is already in progress and 3 hr and 24 hr solutions are being extracted, cleaned and processed using DIPOP 3.1 software. The role of the tropospheric delay and its effect on height estimates when ocean tide loading effects, whether modeled or ignored, would also be investigated.

Rafiq, M.; Santos, M. C.

2004-05-01

98

Habitat partitioning and competitive displacement in cattails (Typha): experimental field studies  

SciTech Connect

A conspicuous feature of many plant communities that is often considered evidence of competitive displacement is the segregation of species along a habitat gradient. The extent of competitive displacement is examined in a recently established association of cattails (Typha latifolia L. and T. angustifolia L.). To accomplish this, potential and realized distributions of these two species were compared along a gradient of water depth in a small pond. These two species together comprised more than 95% of the plant biomass along the gradient and as such constituted a natural two-species association. Comparisons between potential and realized distributions permit a direct estimate of the reductions in abundance of each species by the presence of the other species and the reduction in potential niche overlap along the habitat gradient. In addition, the study of competitive interactions between T. latifolia and T. angustifolia provides us with an opportunity to evaluate the classification of these two species as respectively r-selected and K-selected (McNaughton 1975).

Grace, J.B.; Wetzel, R.G.

1981-10-01

99

Optics for five-dimensional measurement for correction of vertical displacement error due to attitude of floating body in superconducting magnetic levitation system  

SciTech Connect

An improved optical system for five-dimensional measurement has been developed for the correction of vertical displacement error due to the attitude change of a superconducting floating body that shows five degrees of freedom besides a vertical displacement of 10 mm. The available solid angle for the optical measurement is extremely limited because of the cryogenic laser interferometer sharing the optical window of a vacuum chamber in addition to the basic structure of the cryogenic vessel for liquid helium. The aim of the design was to develop a more practical as well as better optical system compared with the prototype system. Various artifices were built into this optical system and the result shows a satisfactory performance and easy operation overcoming the extremely severe spatial difficulty in the levitation system. Although the system described here is specifically designed for our magnetic levitation system, the concept and each artifice will be applicable to the optical measurement system for an object in a high-vacuum chamber and/or cryogenic vessel where the available solid angle for an optical path is extremely limited.

Shiota, Fuyuhiko; Morokuma, Tadashi [National Metrology Institute of Japan (NMIJ), AIST, Tsukuba Central 3, 1-1-1 Umezono, Ibaraki 305-8563 (Japan); Tokyo Denki University, 2-2 Kanda-Nishiki-cho, Chiyoda-ku, Tokyo 101-8457 (Japan)

2006-09-15

100

FARADAY ROTATION MEASURE DUE TO THE INTERGALACTIC MAGNETIC FIELD  

SciTech Connect

Studying the nature and origin of the intergalactic magnetic field (IGMF) is an outstanding problem of cosmology. Measuring Faraday rotation would be a promising method to explore the IGMF in the large-scale structure (LSS) of the universe. We investigated the Faraday rotation measure (RM) due to the IGMF in filaments of galaxies using simulations for cosmological structure formation. We employed a model IGMF based on turbulence dynamo in the LSS of the universe, it has an average strength of (B) {approx} 10 nG and a coherence length of several x 100 h {sup -1} kpc in filaments. With the coherence length smaller than the path length, the inducement of RM would be a random walk process, and we found that the density peak along the line of sight dominantly contributes to the resultant RM. The root mean square of RM through filaments at the present universe was predicted to be {approx}1 rad m{sup -2}. In addition, we predicted that the probability distribution function of |RM| through filaments follows the lognormal distribution, and the power spectrum of RM in the local universe peaks at a scale of {approx}1 h {sup -1} Mpc. Our prediction of RM could be tested with future instruments.

Akahori, Takuya [Research Institute of Basic Science, Chungnam National University, Daejeon (Korea, Republic of); Ryu, Dongsu, E-mail: akataku@canopus.cnu.ac.k, E-mail: ryu@canopus.cnu.ac.k [Department of Astronomy and Space Science, Chungnam National University, Daejeon (Korea, Republic of)

2010-11-01

101

Generalization of the iterative dissipative method for modeling electromagnetic fields in nonuniform media with displacement currents  

Microsoft Academic Search

The iterative dissipative method (IDM) is based on the simple fact that current induced in a conductive medium is in some sense smaller than the external current generating the field. This statement is a theorem based on the energy conservation law of the electromagnetic field. The method has been used to calculate electromagnetic fields in complicated, laterally inhomogeneous media. Examples

B. Sh. Singer; E. B. Fainberg

1995-01-01

102

Small displacement normal faults as barriers to fluid flow in the complexly faulted anticline of the Wilmington Field  

SciTech Connect

Fault controlled barriers can significantly affect basin flow dynamics. Fault barriers cause compartmentalization of fluid systems, isolating areas of differing fluid pressure, diagenetic processes, and fluid characteristics. Understanding the effects of relatively difficult to detect, small displacement faults on fluid flow is essential when analyzing basin hydrodynamics. The Wilmington structure is a SE plunging asymmetric anticline cut by a series of N-S oriented normal faults in the west and NW-SE oriented normal faults in the east. Fault displacement varies within the field from no displacement at fault tips, to the maxima for each fault, which varies from 10m to 135m. Faults are truncated at a mid Pliocene unconformity above which sediments are neither folded nor faulted. Over 2000 deviated wells penetrate the structure in a sixteen square mile area, often crossing the high angle normal faults. We are first performing a detailed analysis of fault geometry and degree of offset from well logs and a 3D seismic survey. A core recovered through the Temple Avenue fault shows slip over a ten meter zone without a dominant slip plane. Well logs also indicate a zone of deformation associated with the fault. A barrier was present, prior to development, across the fault where offset is less than the thickness of the offset reservoir unit, indicating fault zone properties are responsible for formation of the barrier. Fault barriers are established from offset oil-water contacts, pressure, and production surveys. Preliminary analysis of pressure data shows variability across the field and a lack of fluid communication over short distances.

Teas, P.A.; Thornburg, J. (Univ. of Southern California, Santa Cruz, CA (United States))

1996-01-01

103

Experimental and numerical in-plane displacement fields for determine the J-integral on a PMMA cracked specimen  

NASA Astrophysics Data System (ADS)

Contrary to J-integral values calculated from the 2D numerical model, calculated J-integrals [1] in the 3D numerical and 3D experimental cases are not very close with J-integral used in the literature. We can note a problem of structure which allows three-dimensional effects surrounding the crack tip to be seen. The aim of this paper is to determine the zone where the Jintegral formulation of the literature is sufficient to estimate the energy release rate (G) for the 3D cracked structure. For that, a numerical model based on the finite element method and an experimental setup are used. A grid method is adapted to experimentally determine the in-plane displacement fields around a crack tip in a Single-Edge-Notch (SEN) tensile polymer (PMMA) specimen. This indirect method composed of experimental in-plane displacement fields and of 2 theoretical formulations, allows the experimental J-integral on the free-surface to be determined and the results obtaining by the 3D numerical simulations to be confirmed.

Hedan, S.; Valle, V.; Cottron, M.

2010-06-01

104

Scale-dependent bias due to primordial vector fields  

NASA Astrophysics Data System (ADS)

Anisotropic stress perturbations induced by primordial Gaussian vector fields create non-Gaussianity in curvature perturbations. We found that such non-Gaussianity closely resembles the local-type non-Gaussianity parametrized by fNL, and generates scale-dependent bias in large-scale structures. We also found a simple relationship between the scale-dependent bias and the power spectrum of the vector fields. When the vector fields are interpreted as primordial magnetic fields, the effective fNL is shown to be always negative. The scale-dependent bias provides a new approach to probing primordial vector fields.

Shiraishi, Maresuke; Yokoyama, Shuichiro; Ichiki, Kiyotomo; Matsubara, Takahiko

2013-07-01

105

Europa's Alfvén wing: shrinkage and displacement influenced by an induced magnetic field  

Microsoft Academic Search

The Galileo magnetometer data are used to investigate the structure of the Alfvén wing during three flybys of Europa. The presence of an induced magnetic field is shown to shrink the cross section of the Alfvén wing and offset it along the direction radial to Jupiter. Both the shrinkage and the offset depend on the strength of the induced field.

M. Volwerk; K. Khurana; M. Kivelson

2007-01-01

106

Compositional effects on displacement mechanisms of the micellar fluid injected in the Sloss field test  

SciTech Connect

The performance of the micellar/polymer flood conducted in the Sloss reservoir did not follow predictions by a streamtube model. The model assumed that micellar flood displaces oil and water in a piston-type miscible manner with a final oil saturation of 5% PV, and sulfonate retention based on short-term laboratory adsorption tests. This paper, in conjunction with a complementary paper, describes process mechanisms needed to model the flood performance. The results of laboratory studies show higher sulfonate retention caused by ion-exchange effects, which result in partitioning of sulfonate into the oil phase and higher adsorption caused by long contact times. Long-term aging of the Sloss micellar fluid at the high reservoir temperature (93.3/sup 0/C (200/sup 0/F)) does not reduce oil recovery. The results of laboratory studies also show that the final oil saturation after micellar flooding is capillary-number dependent. A higher final oil saturation can be the result of reduced injectivity/productivity, increased interfacial tension (IFT), and/or decreased viscosity.

Gupta, S.P.

1984-02-01

107

Mean-square error due to gradiometer field measuring devices.  

PubMed

Gradiometers use spatial common mode magnetic field rejection to reduce interference from distant sources. They also introduce distortion that can be severe, rendering experimental data difficult to interpret. Attempts to recover the measured magnetic field from the gradiometer output will be plagued by the nonexistence of a spatial function for deconvolution (except for first-order gradiometers), and by the high-pass nature of the spatial transform that emphasizes high spatial frequency noise. Goals of a design for a facility for measuring biomagnetic fields should be an effective shielded room and a field detector employing a first-order gradiometer. PMID:1879849

Hatsell, C P

1991-06-01

108

Europa's Alfvén wing: shrinkage and displacement influenced by an induced magnetic field  

NASA Astrophysics Data System (ADS)

The Galileo magnetometer data are used to investigate the structure of the Alfvén wing during three flybys of Europa. The presence of an induced magnetic field is shown to shrink the cross section of the Alfvén wing and offset it along the direction radial to Jupiter. Both the shrinkage and the offset depend on the strength of the induced field. The entry and exit points of the spacecraft into and out of the Alfvén wings are modeled to determine the angle between the wings and the background magnetic field. Tracing of the Alfvén characteristics in a model magnetic field consisting of Jupiter's background field and an induced field in Europa produces an offset and shrinking of the Alfvén wing consistent with the geometric modeling. Thus we believe that the Alfvén wing properties have been determined correctly. The Alfvén wing angle is directly proportional to the local Alfvén velocity, and is thus a probe for the local plasma density. We show that the inferred plasma density can be understood in terms of the electron density measured by the plasma wave experiment. When Europa is located in the Jovian plasma sheet the derived mass-per-charge exceeds the previous estimates, which is a result of increased pickup of sputtered ions near the moon. The estimated rate of O2+ pickup agrees well with the results from numerical models.

Volwerk, M.; Khurana, K.; Kivelson, M.

2007-05-01

109

Full field displacement measurement by double symmetrical illumination with diode lasers through a pair of double exposure reflectionholograms  

NASA Astrophysics Data System (ADS)

Compact and stable phase stepping interferometer for shape and full field displacement measurement in static and in “real time” operation mode is presented. Double symmetrical illumination of the object in two orthogonal planes with diode lasers, emitting in NIR (790 nm and 830 nm), through a four-exposure reflective holographic optical element (Denisiyk's volume reflection holograms of a reference plane) is applied. The proposed four channels one-beam interferometer is very compact, as the diode lasers without collimators and spatial filters are used directly for reconstruction of the reference planes from a pair of double exposure reflection holograms and for object's illumination through the same holographic optical element. Phase stepping is introduced simply by precise increments of the diode lasers current. By introduction of removable sinusoidal phase gratings and removal of the holographic optical element, the system operates as a single-shot fringe projection profilometer for shape measurement that is essential for precise estimation of displacement vector's components. The proposed system is very stable against external noise, produced by vibrations, temperature changes, air flows, as well as against the influence of object's “rigid body” motion, as the compact and low weight interferometer can be stably fixed directly onto the measured construction.

Sainov, V.; Baldjiev, A.; Stoykova, E.

2013-06-01

110

Studies in space orientation. IV. Further experiments on perception of the upright with displaced visual fields  

Microsoft Academic Search

The effects of visual frameworks of different tilt and of different bodily positions upon perception of the upright were investigated in 53 adult Ss. The visual field consisted of a simple luminous frame contained in a completely darkened room. Within the frame was a luminous rod which the S had to set to the vertical and horizontal. The frame was

H. A. Witkin; S. E. Asch

1948-01-01

111

Semi-diurnal and diurnal variation of errors in GPS precipitable water vapor at Tsukuba, Japan caused by site displacement due to ocean tidal loading  

NASA Astrophysics Data System (ADS)

Simultaneous GPS and water vapor radiometer (WVR) observations were carried out at Tsukuba, Japan from May 1 to June 30, 1998. The precise point positioning method of the GIPSY/OASIS-II software package (GIPSY) was used to retrieve precipitable water vapor (GPS_PWV) from GPS data, which was then compared with precipitable water vapor observed by WVR (WVR_PWV). They agreed quite well with the root mean square difference of less than 1.5 mm. However, periodic variations were found in the difference between GPS_PWV and WVR_PWV (dPWV). It was also found that semi-diurnal or diurnal components of these variations had a positive correlation with site displacement due to Ocean Tidal Loading (OTL). Two months of dPWV data were decomposed by the period of a component of OTL, and then composite time series data with a period equal to that of the component were made. This process was performed for K1, O1, M2, and S1 components of OTL. In each component, a periodic variation in dPWV appeared which was similar to those of the simulated GPS_PWV errors from OTL effects calculated with 'GOTIC' (Sato and Hanada, 1984), a program for the computation of OTL effect. Inclusion of OTL effects into GIPSY analysis reduced dPWV. In the M2 component, the amplitude of the dPWV was reduced by about 80%. This suggests that the OTL components calculated by the GOTIC succeeded in simulating the actual site displacement by OTL effects in Japan. On the other hand, in K1 components, the amplitude of dPWV without OTL in GIPSY is 1.5 times larger than the simulated GPS_PWV error, with considerable error remaining even in the case of GIPSY analysis with OTL. The error may be due to multi-path effect, temperature dependency on conversion from Zenith Wet Delay to PWV, or instrument dependency of WVR on temperature. Analysis utilizing much longer data periods than the present two months is required to overcome these difficulties.

Shoji, Y.; Nakamura, H.; Aonashi, K.; Ichiki, A.; Seko, H.; Members of GPS/MET Japan Summer Campaign 1997 in Tsukuba

2000-10-01

112

The Limitation on Coronal Models Due to Magnetic Field Extrapolation  

NASA Astrophysics Data System (ADS)

There has recently been significant progress in generating realistic models of the solar coronal. Though full 3D models of the solar corona are on the horizon, it is currently not feasible to generate these models at the resolution required to meet observational specifications. It is now possible, however, to use 1D solutions to the hydrodynamic equations to create 3D models of the solar corona at the required resolution. In these 1D-to-3D models, the magnetic field is first extrapolated from photospheric field measurements, and then the field lines are populated with solutions to the 1D hydrodynamic equations. Observational constraints limit the heating functions used in the 1D solution. By far, the most uncertain aspect of this method is the magnetic field geometry; the lack of an extrapolation method that returns magnetic field lines that adequately reflect the true magnetic field limits the success of this method. In this talk, I will compare solar coronal models calculated using different extrapolation methods to the observed data and discuss the results.

Winebarger, A. R.

2011-12-01

113

Neutron star deformation due to multipolar magnetic fields  

NASA Astrophysics Data System (ADS)

Certain multiwavelength observations of neutron stars, such as intermittent radio emissions from rotation-powered pulsars beyond the pair-cascade death line, the pulse profile of the magnetar SGR 1900+14 after its 1998 August 27 giant flare and X-ray spectral features of PSR J0821-4300 and SGR 0418+5729, suggest that the magnetic fields of non-accreting neutron stars are not purely dipolar and may contain higher order multipoles. Here, we calculate the ellipticity of a non-barotropic neutron star with (i) a quadrupole poloidal-toroidal field, and (ii) a purely poloidal field containing arbitrary multipoles, deriving the relation between the ellipticity and the multipole amplitudes. We present, as a worked example, a purely poloidal field comprising dipole, quadrupole and octupole components. We show the correlation between field energy and ellipticity for each multipole, that the l = 4 multipole has the lowest energy, and that l = 5 has the lowest ellipticity. We show how a mixed multipolar field creates an observationally testable mismatch between the principal axes of inertia (to be inferred from gravitational wave data) and the magnetic inclination angle. Strong quadrupole and octupole components (with amplitudes ˜102 times higher than the dipole) in SGR 0418+5729 still yield ellipticity ˜10-8, consistent with current gravitational wave upper limits. The existence of higher multipoles in fast-rotating objects (e.g. newborn magnetars) has interesting implications for the braking law and hence phase tracking during coherent gravitational wave searches.

Mastrano, A.; Lasky, P. D.; Melatos, A.

2013-09-01

114

The origin of intergalactic magnetic fields due to extragalactic jets  

Microsoft Academic Search

The paper studies large-scale magnetization of intra- and intercluster media due to electric current-carrying extragalactic jets generated by active periods of galactic nuclei. The Lorentz force acting on the return current path has an expansive character which is responsible for the generation of a growing magnetic cocoon surrounding the associated jet. It is shown that such growing cocoons can be

Luiz C. Jafelice; Reuven Opher

1992-01-01

115

Electric fields in the human body due to electrostatic discharges.  

PubMed

Electrostatic discharges (ESDs) occur when two objects at different electric potentials come close enough to arc (spark) across the gap between them. Such discharges may be either single-event or repetitive (e.g., 60 Hz). Some studies have indicated that ESDs may be a causative factor for health effects in electric utility workers. Moreover, a hypothesis has recently been forwarded imperceptible contact currents in the human body may be responsible for health effects, most notably childhood leukemia. Numerical modeling indicates that the electric fields in human tissue resulting from typical contact currents are much greater than those induced from typical exposures to electric and magnetic fields at power line frequencies. Numerical modeling is used here to compute representative spark-discharge dosimetry in a realistic human adult model. The frequency-domain scalar potential finite difference method is applied in conjunction with the Fourier transform to assess electric fields in selected regions and tissues of interest in the body. Electric fields in such tissues as subcutaneous fat (where peripheral nerves may be excited), muscle and bone marrow are of the order of kilovolts per meter in the lower arm. The pulses, however, are of short duration (approximately 100 ns). PMID:15311833

Dawson, T W; Stuchly, M A; Kavet, R

2004-08-01

116

Nonequilibrium Flow Fields Due to Spatial Piston Motions.  

National Technical Information Service (NTIS)

The inviscid flow resulting from imposing a prescribed piston motion on a gas field previously at rest is examined. The gas model is presumed to possess several energy modes, one of which requires a finite time to approach thermodynamic equilibrium. A uni...

M. B. Sussman

1966-01-01

117

Dose uncertainty due to aperture effects in dynamic fields  

SciTech Connect

Dosimetry of intensity modulated radiation therapy requires accurate modeling of the beamlets that comprise each treatment segment. Planning systems such as Varian Eclipse and Philips Pinnacle recommend measuring dose distributions and output factors for fields as small as possible, generally down to at least 2x2 cm{sup 2}. Conventionally, we perform these measurements for regular fields, defined by the secondary collimators. In practice, it is the multileaf collimation system (MLC) that defines the intensity map and provides dynamic dose modulation in either a moving window or segmented step-and-shoot mode. For this review we have only considered the latter delivery mode. Using this method, we have studied aperture motion effects on the dynamic collimator scatter (S{sub c}), total scatter (S{sub c,p}), and phantom scatter (S{sub p}) factors for various combinations of collimator settings (4x4-14x40 cm{sup 2}) and dynamically stepped leaf gaps (0.1 to 1.0 cm) in comparison with those for static field factors. For two different Varian linear accelerators, we found similar results in a systematic dependence of collimator scatter on gap width and collimator setting. As the gap increases from 0.1 to 1.0 cm the dynamic collimator scatter factors converge from a maximum difference of about 30% toward the static field values. At the same time, there is no measurable difference between dynamic field phantom scatter factors and those conventionally obtained for static fields. Second, we evaluated the two planning systems as to how well they account for collimator scatter by attempting to mimic the dynamic apertures used above by planning and measuring dose distributions to several small, cylindrical targets for a similar range of fixed collimator settings. We found that the ratio of measured-to-planned doses as a function of target size were similar to the measured, dynamic S{sub c} data for the Varian Eclipse planning system, indicating underestimation of dose for targets smaller than 1 cm diameter, but were close to unity for the Philips Pinnacle system, suggestive of the underlying differences in the dose calculation algorithms. We discuss the measurements and results and potential impact on the dosimetry of small clinical targets.

Higgins, P. D.; Alaei, P. [Department of Therapeutic Radiology-Radiation Oncology, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

2006-07-15

118

Chaotic magnetic fields due to asymmetric current configurations - application to cross-field diffusion of particles in cosmic rays  

Microsoft Academic Search

The observed cross-field diffusion of charged particles in cosmic ray transport is assumed to be due to chaotic nature of the interplanetary\\/intergalactic magnetic fields. The particles are accelerated and energized by the temporal fluctuations of the magnetic field. The generation of chaotic magnetic fields is ad hoc and the characteristics of the fields are chosen to satisfy the observations. We

B. Dasgupta; A. K. Ram

2007-01-01

119

Chaotic Magnetic Fields due to Asymmetric Current Configurations - Modeling Cross-Field Diffusion of Charged Particles in Cosmic Rays  

Microsoft Academic Search

The observed cross-field diffusion of charged particles in cosmic ray transport is assumed to be due to chaotic nature of the interplanetary\\/intergalactic magnetic fields. The particles are accelerated and energized by the temporal fluctuations of the magnetic field. The generation of chaotic magnetic fields is ad hoc and the characteristics of the fields are chosen to satisfy the observations. We

A. K. Ram; B. Dasgupta

2007-01-01

120

Enhanced nucleation fields due to dipolar interactions in nanocomposite magnets  

NASA Astrophysics Data System (ADS)

One approach to construct powerful permanent magnets while using less rare-earth elements is to combine a hard magnetic material having a high coercive field with a soft magnetic material having a high saturation magnetization at the nanometer scale and create so-called nanocomposite magnets. If both materials are strongly coupled, exchange forces will form a stable magnet. We use finite element micromagnetics simulations to investigate the changing hysteresis properties for varying arrays of soft magnetic spherical inclusions in a hard magnetic body. We show that the anisotropy arising from dipolar interactions between soft magnetic particles in a hard magnetic matrix can enhance the nucleation field by more than 10% and strongly depends on the arrangement of the inclusions.

Fischbacher, Johann; Bance, Simon; Exl, Lukas; Gusenbauer, Markus; Oezelt, Harald; Reichel, Franz; Schrefl, Thomas

2013-03-01

121

Weed seed loss due to predation in Michigan maize fields  

Microsoft Academic Search

The influence of weed seed predation by invertebrates and vertebrates was examined in relation to distance from hedgerows in maize fields of southwestern Michigan. Experiments were conducted in spring and winter and included five common weed species, i.e., velvet-leaf (Abutilon theophrasti), redroot pigweed (Amaranthus retroflexus), common lamb's-quarters (Chenopodium album), fall panicum (Panicum dichotomiflorum), and yellow foxtail (Setaria lutescens). In the

Paul C. Marino; Katherine L. Gross; Douglas A. Landis

1997-01-01

122

Cross-Magnetic-Field Diffusion Due To Quasibound State Formation  

NASA Astrophysics Data System (ADS)

Classical trajectory simulations indicate that quasibound states of hydrogen (or antihydrogen) can form in low density magnetized plasmas [C. E. Correa, J. R. Correa, and C. A. Ordonez, Phys. Rev. E 72 (2005) 046406.]. Such quasibound states form at positive energies, where the energy of the two-particle system is defined to be zero when the electron and proton are at rest with infinite separation. The formation of quasibound states may affect the rate of diffusion of electrons across a magnetic field. Electron diffusion transverse to a magnetic field occurs, in part, because the guiding center position of an electron shifts with each binary interaction between an electron and a proton. The shift associated with a single binary interaction is normally not larger than a typical cyclotron radius. However, simulations indicate that a binary interaction that results in the formation of a quasibound state can cause a shift of the electron guiding center that is much larger than the cyclotron radius before the interaction. An assessment of the effect that the formation of quasibound states may have on electron cross-field diffusion is presented.

Ahat, Yasin; Ordonez, Carlos

2006-04-01

123

Full-field dynamic displacement and strain measurement using pulsed and high-speed 3D image correlation photogrammetry  

NASA Astrophysics Data System (ADS)

3D image correlation is a robust method for measuring full-field displacements and strains using a calibrated pair of video cameras. Underlying principles and benefits are reviewed, and the method is compared to both 3D ESPI and 2D image correlation. Several applications combining image correlation photogrammetry with stroboscopic illumination and/or high-speed video cameras are presented. Operational strains in ionic polymeric muscle samples and electro-restrictive actuators are determined. The use of short-duration white light pulses to study automobile tires on road wheels at speeds up to 150 miles per hour is demonstrated. Initial work measuring strains on an 18" flywheel in a spin pit at up to 35,000 rpm is described. A notched rubber dogbone sample is pulled to failure at 125% strain in 38 milliseconds, and hundreds of full-field strain maps are captured. This paper includes discussion of sample preparation methods and special lighting systems, including pulsed arc lamps and pulsed lasers. A matrix of capability using available high speed cameras is included.

Schmidt, Timothy; Tyson, John; Galanulis, Konstantin

2004-02-01

124

Thickness measurement of full field soap bubble film in real time based on large lateral shearing displacement interferometry  

NASA Astrophysics Data System (ADS)

Soap bubble has a profile nearly the same as a perfect sphere. Many researches focus on the measurement of the film thickness of the soap bubble over time in order to calculate the film drainage rate. Its thickness variation in gravitation field can be respectively approximated with many models, considering the cost and precision in different applications. In this research, fringe patterns of a soap bubble were captured continuously using the large lateral shearing displacement interferometry during the process from its formation to burst. From the analysis of three typical frames, it can be seen that the film thickness distribution along the gravity orientation shows a very good agreement with an exponential model. The ratio of its maximum error to the laser wavelength is 3/8, existing at the sphere's center. Moreover, it can be seen that the absolute value of the parameter k in the exponential model keeps increasing over time, while the parameter b keeps decreasing over time. Based on the parameter k from the exponential model, the maximum limit in the thickness measurement of the soap bubble film can be calculated from the function of the fringe pattern's resolution and its field coordinates. The result shows that there is a special point above the sphere's center, being the right place where the gradient of phase order changes its sign. The region near this point presents very high limitation in the film thickness measurement.

Lv, Wei; Zhou, Huai-Chun; Zhu, Jin-Rong

2012-03-01

125

Transport infrastructure monitoring: A ground based optical displacement monitoring system, field tests on a bridge, the Musmeci's bridge in Potenza, Italy.  

NASA Astrophysics Data System (ADS)

A gound based optical displacement monitoring system, "NIODIM", is being developed by Norsk Elektro Optikk in the framework of the activities of the European project "Integrated System for Transport Infrastructure surveillance and Monitoring by Electromagnetic Sensing" (ISTIMES), funded in the 7th Framework Programme (FP7/2007-2013). The optical displacement monitoring system has now participated in two real life field campaigns one in Switzerland and one in Italy. The latter, the tests in Potenza, Italy, will be presented in the following. The NIODIM system has undergone some development during the last year to adopt it for use in a somewhat higher frequency domain by changing the camera sensor part. This to make it more useful for monitoring of structures with oscillation frequencies tens of Hz. The original system was intended to a large extent to monitor land slides, quick clay and rock slides and similar phenomena typically having a relatively slow time response. The system has been significantly speeded up from the original 12 Hz. Current tests have been performed at a frame rate of 64 Hz i.e., the camera part and data processing unit have been running on 64Hz. In connection with the tests in Italy the data processing has been upgraded to include sub-pixel resolution i.e., the measurement results are no longer limited by pixel borders or single pixels. The main part of the NIODIM system is a camera capable of operating at a sufficiently high frame rate. This camera will typically be mounted on firm ground and will depict and monitor a reference point, typically a light emitting diode, LED, which will be mounted on the object susceptible to move. A processing unit will acquire the images from the camera part and find the position of the LED in the image and compare that to threshold values and if required raise a warning or an alarm. The NIODIM system can either be a standalone system or be an integrated part of the overall ISTIMES system, the ISTIMES system being a decision support system. Field trials as part of the ISTIMES project took place in Potenza, Italy, for a week in July 2011. The test target was Musmeci's bridge, a bridge with a design where aesthetic values have been just as important as traditional civil engineering aspects. Several technologies and techniques were tested at the same part of the bridge to allow for data correlation between different sensors. The camera and processing parts of the optical displacement monitoring system were mounted on a concrete wall at the one end of the bridge while the LED reference points were mounted on the bridge approximately 40 metres away. The tests at the Musmeci's bridge are successful and verifying some of the findings from the tests in Switzerland. However, we learned a lesson with regards to temporary mounting of the reference points using glossy stainless steel parts. A short period early in the morning, when illuminated by the sun, these stainless steel parts were just as bright as the LED reference point leading to potential noise in the measurements. Due to availability of the raw data this could be fixed later doing post processing on the stored data. One of the findings was that we have relatively large time of day variation that appear to be periodic with a cycle time of about 24 hours, at least with similar weather conditions. These displacements appear to be in the order of 10 mm and is probably due to thermal effects. Several shorter displacements have also been registered with amplitudes of a couple of mm and duration around 10 seconds. These shorter displacement peaks appear to be caused by heavy vehicles passing by on the bridge. The introduction of the processing using sub-pixel resolution looks very promising and appears to give a significant improvement of the actual resolution of the system. Even thought the measurements in the field are successfully completed we have noted larger slowly moving displacements than originally expected. This combined with shorter lasting peaks could lead to measurements above pre-set thres

Hagene, J. K.

2012-04-01

126

Displacement Current and Surface Flashover  

SciTech Connect

High-voltage vacuum insulator failure is generally due to surface flashover rather than insulator bulk breakdown. Vacuum surface flashover is widely believed to be initiated by a secondary electron emission avalanche along the vacuum-insulator interface. This process requires a physical mechanism to cause secondary electrons emitted from the insulator surface to return to that surface. Here, we show that when an insulator is subjected to a fast high-voltage pulse, the magnetic field due to displacement current through the insulator can provide this mechanism. This indicates the importance of the voltage pulse shape, especially the rise time, in the flashover initiation process.

harris, J R; Caporaso, G J; Blackfield, D; Chen, Y J

2007-07-17

127

Gold marker displacement due to needle insertion during HDR-brachytherapy for treatment of prostate cancer: A prospective cone beam computed tomography and kilovoltage on-board imaging (kV-OBI) study  

PubMed Central

Purpose To evaluate gold marker displacement due to needle insertion during HDR-brachytherapy for therapy of prostate cancer. Patients and methods 18 patients entered into this prospective evaluation. Three gold markers were implanted into the prostate during the first HDR-brachytherapy procedure after the irradiation was administered. Three days after marker implantation all patients had a CT-scan for planning purpose of the percutaneous irradiation. Marker localization was defined on the digitally-reconstructed-radiographs (DRR) for daily (VMAT technique) or weekly (IMRT) set-up error correction. Percutaneous therapy started one week after first HDR-brachytherapy. After the second HDR-brachytherapy, two weeks after first HDR-brachtherapy, a cone-beam CT-scan was done to evaluate marker displacement due to needle insertion. In case of marker displacement, the actual positions of the gold markers were adjusted on the DRR. Results The value of the gold marker displacement due to the second HDR-brachytherapy was analyzed in all patients and for each gold marker by comparison of the marker positions in the prostate after soft tissue registration of the prostate of the CT-scans prior the first and second HDR-brachytherapy. The maximum deviation was 5 mm, 7 mm and 12 mm for the anterior-posterior, lateral and superior-inferior direction. At least one marker in each patient showed a significant displacement and therefore new marker positions were adjusted on the DRRs for the ongoing percutaneous therapy. Conclusions Needle insertion in the prostate due to HDR-brachytherapy can lead to gold marker displacements. Therefore, it is necessary to verify the actual position of markers after the second HDR-brachytherapy. In case of significant deviations, a new DRR with the adjusted marker positions should be generated for precise positioning during the ongoing percutaneous irradiation.

2012-01-01

128

A method for determining inhomogeneous displacement fields at a preset resolution on the surface of deformed materials for problems of physical mesomechanics  

Microsoft Academic Search

We present a method for determining the fields of deformations and displacements on the surface of structurally inhomogeneous deformed materials, which is applicable on a mesoscopic level. The approach is based on a special processing of experimentally measured images or spatial distributions of the surface relief height. Results of testing the proposed method and applying it to metal samples are

O. V. Semenova; I. A. Zashivalova; O. A. Morozov

2008-01-01

129

Collective trauma in the Vanni- a qualitative inquiry into the mental health of the internally displaced due to the civil war in Sri Lanka  

Microsoft Academic Search

BACKGROUND: From January to May, 2009, a population of 300,000 in the Vanni, northern Sri Lanka underwent multiple displacements, deaths, injuries, deprivation of water, food, medical care and other basic needs caught between the shelling and bombings of the state forces and the LTTE which forcefully recruited men, women and children to fight on the frontlines and held the rest

Daya Somasundaram

2010-01-01

130

Relationship between breakdown field and radiated electromagnetic field strength due to low voltage ESD below 1kV  

Microsoft Academic Search

Relationship between breakdown field strength and radiated electromagnetic field strength was examined in experimental study. In the first, transition duration of voltage and current rise time due to small gap discharge as the low voltage ESD investigated in time domain. The measurement system used the 12 GHz experimental system. And so, the sensing system was used an E-field sensor and

K. Kawamata; S. Minegishi; A. Haga; O. Fujiwara

2008-01-01

131

Electromagnetic fields due to overhead and buried high-voltage power-lines: a quantitative comparison  

Microsoft Academic Search

Possible health hazards due to nonionizing radiations emanating from high-voltage power-lines are addressed. Specifically, the magnetic field due to power-line radiation has been considered as an etiological factor in some form(s) of childhood cancer. An investigation of the possibility of reducing the magnetic field effect nEar the earth's surface by burying the power lines was conducted. The overall electromagnetic field

Perarnbur S. Neelakanta; V. Ungvichian

1989-01-01

132

Internal Displacement Monitoring Centre  

NSDL National Science Digital Library

The Internal Displacement Monitoring Centre (IDMC) was established twelve years ago in the hope that they would "raise awareness of the plight of internally displaced people (IDP), point to gaps in national and international responses and promote solutions reflecting international standards and best practices." The Centre also keeps a database of 50 countries in which people have been displaced within their own country due to conflicts or human rights violations. To get a sense of where displaced persons are and how many countries have IDPs, visitors can click on the small world map on the far right hand side of the homepage. Scrolling over the map will reveal the number of displaced people by continent. Visitors interested in learning about an individual country can click on the continent, then click on one of the countries for an "Internal Displacement Profile", "Country Statistics", and an "Overview". The Resources tab, at the top of any page, includes "IDMC Publications", "Picture Galleries" of internally displaced people in India, Cyprus, and the West Bank, to name a few, and "IDP Maps" which has dozens of maps of from 2001 to 2009.

133

Suppression of side lobes in a spectrum of fibre Bragg gratings due to the transverse displacement of phase mask with respect to the optical fibre  

SciTech Connect

The possibility of apodisation of fibre Bragg gratings (FBGs) recorded in the interference region of two Gaussian beams in the phase-mask scheme is considered. The FBG reflection spectra are numerically simulated for different values of recordingbeam parameters and the distance between the axes of interfering beams diffracted into different orders, which is varied by transverse displacement of the phase mask with respect to the optical fibre. Suppression of side lobes and smoothing out of the FBG spectrum with an increase in the transverse displacement of the phase mask is experimentally demonstrated. It is shown that this effect is caused by the equalisation of the mean induced refractive index in the FBG region. (optical fibres, lasers and amplifiers. properties and applications)

Abdullina, S R; Nemov, I N; Babin, Sergei A [Institute of Automation and Electrometry, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation)

2012-09-30

134

Displacements and stresses due to a single force in a half-space in welded contact with another half-space  

NASA Astrophysics Data System (ADS)

Closed-form analytical expressions for the displacements and stresses induced by a single force of arbitrary orientation located in an elastic half-space in welded contact with another elastic half-space are obtained. These expressions are valid for arbitrary values of the Poisson's ratio and for arbitrary source and observer locations. The final results are given in a form that makes numerical computation straightforward and accurate.

Singh, Sarva Jit; Kumari, Gulshan; Singh, Kuldip

1999-11-01

135

Frequency analysis of the induced effects due to the lightning stroke radiated electromagnetic field  

Microsoft Academic Search

The effects of a lightning stroke to the protection system of the control building of an industrial plant are investigated. The results of a frequency-analysis study of effects connected with point values of the electromagnetic field generated within the building or due to the presence of radiation fields, namely, fields whose harmonic components, characterized by small wavelengths compared to the

Condettina Buccella; Saverio Cristina; Antonio Orlandi

1992-01-01

136

Field displacement during external radiotherapy in prostatic adenocarcinoma treated with radioactive 198Au implants and external irradiation.  

PubMed

The purpose of this work was to study displacement error and internal movements of the prostate during external beam radiotherapy. Verification films in the frontal (n = 194) and lateral (n = 64) portals were investigated in 14 patients treated with radioactive 198Au implants. Displacement errors of two implants were investigated. In seven patients, filling of the rectum and the bladder with contrast medium or isotonic saline was performed during CT investigation for planning purposes to detect movements of the prostate. Most (95%) of the displacement errors were less than 10 mm in the frontal portal and less than 15 mm in the lateral portals. No correlation to the patient's weight was found. The displacement errors were randomly distributed. The spatial relations between the implants were not altered during the treatments. Small movements of the prostate were observed. To conclude, the positioning system employed at present (laser) can be sufficient for the margins used (2 cm). In lateral portals, however, the system did not have the ability to detect a possible systematic displacement error from simulator to accelerator. The intention is to decrease the margins to 1 cm, which will necessitate a better positioning system. PMID:7492388

Lennernäs, B; Letocha, H; Rikner, G; Magnusson, A; Nilsson, S

1995-01-01

137

Large-scale magnetic fields from inflation due to Chern-Simons-like effective interaction  

NASA Astrophysics Data System (ADS)

We discuss the generation of large-scale magnetic fields due to the breaking of the conformal invariance in an electromagnetic field through the CPT-even dimension-6 Chern-Simons-like effective interaction with a fermion current in inflationary cosmology. It is shown that the magnetic fields on the 1 Mpc scale with the field strength of ~10-9 G at the present time can be generated even for the scale of the effective interaction being the Planck scale.

Bamba, K.; Geng, C. Q.; Ho, S. H.

2008-11-01

138

A method for determining inhomogeneous displacement fields at a preset resolution on the surface of deformed materials for problems of physical mesomechanics  

Microsoft Academic Search

We present a method for determining the fields of deformations and displacements on the surface of structurally inhomogeneous\\u000a deformed materials, which is applicable on a mesoscopic level. The approach is based on a special processing of experimentally\\u000a measured images or spatial distributions of the surface relief height. Results of testing the proposed method and applying\\u000a it to metal samples are

O. V. Semenova; I. A. Zashivalova; O. A. Morozov

2008-01-01

139

Simultaneous Atomic Force Microscope and Quartz Crystal Microbalance Measurements: Interactions and Displacement Field of a Quartz Crystal Microbalance  

Microsoft Academic Search

We analyze the interaction of two instruments often used in material science analysis, the atomic force microscope (AFM) and the quartz crystal microbalance (QCM), here combined in a single instrument for simultaneous measurements on a single sample. We show, using finite element analysis, that the in-plane displacement of a QCM oscillating in liquid with a quality factor of 2000 is

J.-M. Friedt; K. H. Choi; L. Francis; A. Campitelli

2002-01-01

140

Field Assessment of Non-toxigenic Aspergillus flavus Strain K49 in Competitive Displacement of Toxigenic Isolates  

Technology Transfer Automated Retrieval System (TEKTRAN)

Non-toxigenic strains of Aspergillus flavus offer the potential to control aflatoxin contamination by competitive displacement of indigenous populations of A. flavus colonizing corn grain. Two sets of experiments were conducted to assess the competitiveness of strain K49 when challenged against two...

141

CMB temperature anisotropy from broken spatial isotropy due to a homogeneous cosmological magnetic field  

SciTech Connect

We derive the cosmic microwave background temperature anisotropy two-point correlation function (including off-diagonal correlations) from broken spatial isotropy due to an arbitrarily oriented homogeneous cosmological magnetic field.

Kahniashvili, Tina [Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, Kansas 66506 (United States); Department of Physics, Laurentian University, Ramsey Lake Road, Sudbury, ON P3E 2C6 (Canada); National Abastumani Astrophysical Observatory, 2A Kazbegi Ave, Tbilisi, GE-0160 (Georgia); Lavrelashvili, George [Department of Theoretical Physics, A. Razmadze Mathematical Institute, 1 M. Aleksidze, Tbilisi, GE-0193 (Georgia); Ratra, Bharat [Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, Kansas 66506 (United States)

2008-09-15

142

Relativistic Fields Due to a Particle in a Grounded Cylindrical Box.  

National Technical Information Service (NTIS)

The exact relativistic fields inside a perfectly conducting, closed, grounded cylindrical box of finite length, which are due to a charged particle moving down the axis in vacuum, are obtained. This permits construction of the solution for a line segment ...

R. L. Liboff

1969-01-01

143

Collective trauma in the Vanni- a qualitative inquiry into the mental health of the internally displaced due to the civil war in Sri Lanka  

PubMed Central

Background From January to May, 2009, a population of 300,000 in the Vanni, northern Sri Lanka underwent multiple displacements, deaths, injuries, deprivation of water, food, medical care and other basic needs caught between the shelling and bombings of the state forces and the LTTE which forcefully recruited men, women and children to fight on the frontlines and held the rest hostage. This study explores the long term psychosocial and mental health consequences of exposure to massive, existential trauma. Methods This paper is a qualitative inquiry into the psychosocial situation of the Vanni displaced and their ethnography using narratives and observations obtained through participant observation; in depth interviews; key informant, family and extended family interviews; and focus groups using a prescribed, semi structured open ended questionnaire. Results The narratives, drawings, letters and poems as well as data from observations, key informant interviews, extended family and focus group discussions show considerable impact at the family and community. The family and community relationships, networks, processes and structures are destroyed. There develops collective symptoms of despair, passivity, silence, loss of values and ethical mores, amotivation, dependency on external assistance, but also resilience and post-traumatic growth. Conclusions Considering the severity of family and community level adverse effects and implication for resettlement, rehabilitation, and development programmes; interventions for healing of memories, psychosocial regeneration of the family and community structures and processes are essential.

2010-01-01

144

A numerical model to simulate micro-fracture of field hockey players due to jumping  

Microsoft Academic Search

A linear elastic fracture mechanics approach has been considered to understand the impact behavior of ankles and knees due to jumping. By using a crack increment model and a fatigue crack propagation model, simulation of the fracture due to repetitive jumps are evaluated. To aid the numerical calculation, an experimental study on standing jump by two Indian field hockey players

M. S. Hasan; H. Singh Ranu; J. E. Lander

1996-01-01

145

Drawdown distribution due to well fields in coupled leaky aquifers: 2. Finite aquifer system  

Microsoft Academic Search

Solutions for the drawdown distribution due to the operation of well fields in coupled leaky aquifers of infinite areal extent are available. This paper is concerned with the drawdown distribution caused by the pumping of well fields in coupled leaky aquifers of finite areal extent. A transform to solve the flow problem is obtained by the modification of the zero-order

Z. A. Saleem; C. E. Jacob

1974-01-01

146

Acceleration of electrons and solar flares due to quasi-static electric field  

Microsoft Academic Search

The storage of flare energy, efficient acceleration of electrons and the trigger of the flares are suggested to be attributed to a quasi-static electric field caused by a gas motion near the photosphere without satisfying the frozen condition. The primary cause of the onset of flares would be the acceleration of electrons due to the electric field above a critical

Tatsuo Takakura

1971-01-01

147

Electric and Magnetic Fields at the Earth's Surface Due to Auroral Currents  

Microsoft Academic Search

The horizontal components of the electric and magnetic fields due to auroral atmospheric currents are calculated at the surface of the earth. For sinusoidal changes in the earth's magnetic field (Fourier frequency components of actual nonsinusoidal variations), a lower limit of the corresponding earth-surface potential is obtained by considering a line-type auroral current over a nonuniform stratified earth. An upper

VERNON D. ALBERTSON; JOHAN A. VAN BAELEN

1970-01-01

148

Energy shifts of Rydberg atoms due to patch fields near metal surfaces  

SciTech Connect

The statistical properties of patch electric fields due to a polycrystalline metal surface are calculated. The fluctuations in the electric field scale like 1/z{sup 2} when z>>w, where z is the distance to the surface and w is the characteristic length scale of the surface patches. For typical thermally evaporated gold surfaces these field fluctuations are comparable to the image field of an elementary charge, and scale in the same way with distance to the surface. Expressions for calculating the statistics of the inhomogeneous broadening of Rydberg-atom energies due to patch electric fields are presented. Spatial variations in the patch fields over the Rydberg orbit are found to be insignificant.

Carter, J. D.; Martin, J. D. D. [Department of Physics and Astronomy and Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada)

2011-03-15

149

Examining the departure in response of non-point detectors due to non-uniform illumination and displacement of effective center  

NASA Astrophysics Data System (ADS)

A mathematical simulation approach based on the general purpose Monte Carlo N-particle transport code MCNP was developed to calculate the departure in reading of the neutron spectrometer instrument from that expected according to the inverse square law. The calculations were performed to evaluate the effects of beam divergence on the response of a 10 in. spherical device equipped with a long BF3 counter irradiated by 11 mono-energy neutron beams. The necessary geometry correction factor, because of non-uniform illumination, for the calibration of seven polyethylene spheres with several radionuclide neutron sources, i.e. Ra–Be, 241Am–Be, 241Am–B and Po–Be sources was also determined. In all calculations, the displacement of effective center from the geometric center of moderating spheres, when used as an instrument for neutron fluence measurement, was quantified.

Khabaz, Rahim

2013-11-01

150

Tidal station displacements  

Microsoft Academic Search

Theoretical modeling of the station displacements produced by tidal deformations of the Earth due to lunisolar gravitational forces is a necessary part of the analysis of space geodetic data. To attain the accuracies demanded by the precision of the data, a generalized version of the Love number formalism has to be used wherein the classical Love and Shida numbers are

P. M. Mathews; V. Dehant; John M. Gipson

1997-01-01

151

Low-field large magnetostriction in DyCo2 due to field-induced rearrangement of tetragonal variants  

NASA Astrophysics Data System (ADS)

The synchrotron high-energy x-ray diffraction was used to trace directly the structural evolution of polycrystalline DyCo2, one of RT2 (R = rare earth, T = Co, Fe) compounds with Laves phase, as a function of temperature and magnetic field. When the DyCo2 compound was zero-field cooled down below TC, the high temperature cubic lattice was distorted into tetragonal structure, associated with an expansion of unit cell volume. It was further found that the large magnetostriction at low magnetic field was due to the preferential rearrangement of tetragonal variants in the low-temperature ferrimagnetic phase. Our finding of the field-driven preferential selection of tetragonal variants in the polycrystalline materials provides important clues for exploring the advanced ferromagnetic alloys with a large magnetostriction at low field.

Nie, Zhihua; Yang, Sen; Wang, Yandong; Wang, Zilong; Liu, Dongmei; Ren, Yang

2013-09-01

152

Gyro-electron ghost images due to microchannel plate operation in transverse magnetic fields  

SciTech Connect

A multi-anode microchannel plate (MCP) detector was operated in a transverse magnetic field. When a collimated ion beam of approx.4-mm diameter impinged on one area of the plate, ghost images were observed elsewhere on the plate at anodes up to several centimeters from the beam spot. This effect is due to secondary electrons which are emitted from the interstitial surfaces around the MCP pores and returned to the surface of the plate under the influence of E-tilde X B-tilde fields, where E-tilde is the electric field perpendicular to the plate due to the MCP bias potential and B-tilde is the externally applied transverse magnetic field. A regenerative process is observed in which the secondary electrons traverse the surface of the plate in the E-tilde X B-tilde direction by successive gyro-orbit steps. A method for suppressing the ghost images is discussed.

Roquemore, A.L.; Medley, S.S.

1986-06-01

153

Calculation of the magnetic field due to a bioelectric current dipole in an ellipsoid  

Microsoft Academic Search

The bioelectric current dipole model is important both theoretically and computationally in the study of electrical activity\\u000a in the brain and stomach due to the resemblance of the shape of these two organs to an ellipsoid. To calculate the magnetic\\u000a field B due to a dipole in an ellipsoid, one must evaluate truncated series expansions involving ellipsoidal harmonics $$\\u000a\\\\mathbb{E}_n^m

Andrei Irimia

2008-01-01

154

New Phenomena in Propagation of Radio Polarizations due to Magnetic Fields on Cosmological Scales  

SciTech Connect

We discuss a new mechanism which could cause a rotation of polarization of electromagnetic waves due to magnetic fields on cosmological scales. The effect hinges on the geometrical phase of Pancharatnam and Berry, and causes a corkscrew twisting of the plane of polarization. The new effect represents an additional tool that allows possible intergalactic and cosmological magnetic fields to be studied using radio propagation. {copyright} {ital 1998} {ital The American Physical Society}

Ralston, J.P. [Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas 66044 (United States); Jain, P. [Physics Department, I. I. T., Kanpur, (India) 208016; Nodland, B. [Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States)

1998-07-01

155

Shot noise of low energy electron field emission due to Klein tunneling  

NASA Astrophysics Data System (ADS)

This paper investigates the property of shot noise for low energy electron field emission from a single-layer vertically aligned graphene sheet assuming the emission process is due to Klein tunneling. In our model, we use two different methods (relativistic WKB and transfer matrix) to calculate the transmission coefficient and thus obtain the Fano factor (? or suppression of shot noise) as a function of temperature T, Fermi energy Ef, and local electric field F. It is found that a universal maximum value of about ? = 1/3 can be reached at low temperature limit within a certain range of local electric field.

Sun, S.; Ang, L. K.

2012-07-01

156

ANALYSIS OF HIGH FIELD NON-LINEAR LOSSES ON SRF SURFACES DUE TO SPECIFIC TOPOGRAPHIC ROUGHNESS  

SciTech Connect

The high-field performance of SRF cavities will eventually be limited by the realization of fundamental material limits, whether it is Hc1 or Hsh, or some derivative thereof, at which the superconductivity is lost. Before reaching this fundamental field limit at the macro level, it must be encountered at localized, perhaps microscopic, sites of field enhancement due to local topography. If such sites are small enough, they may produce thermally stabilized normal-conducting regions which contribute non-linear losses when viewed from the macro resonant field perspective, and thus produce degradation in Q0. We have undertaken a calculation of local surface magnetic field enhancement from specific fine topographic structure by conformal mapping method and numerically. A solution of the resulting normal conducting volume has been derived and the corresponding RF Ohmic loss simulated.

Chen Xu,Charles Reece,Michael Kelley

2012-07-01

157

Faraday Rotation Measure due to the Intergalactic Magnetic Field. II. The Cosmological Contribution  

Microsoft Academic Search

We investigate the Faraday rotation measure (RM) due to the intergalactic magnetic field (IGMF) through the cosmic web up to cosmological distances, using a model IGMF based on turbulence dynamo in the large-scale structure of the universe. By stacking the IGMF and gas density data up to redshift z = 5 and taking account of the redshift distribution of polarized

Takuya Akahori; Dongsu Ryu

2011-01-01

158

Electric field effects on fluorescence quenching due to electron transfer. II. Linked donor-acceptor systems  

Microsoft Academic Search

A theoretical model has been proposed and applied to explain recent experimental results concerning the external electric field effect on fluorescence quenching due to intramolecular electron transfer in donor-acceptor pairs linked by a spacer. These results show that for some systems with a short length of a spacer and for a very low concentration of donor-acceptor pairs, the fluorescence quenching

Maria Hilczer; M. Tachiya

2002-01-01

159

Relativistic Fields Due to a Particle in a Grounded Cylindrical Box.  

National Technical Information Service (NTIS)

The exact relativistic fields inside a perfectly conducting, closed, grounded cylindrical box of finite length, which are due to a charged particle moving down the axis in vacuum are obtained. This permits construction of the solution for a line segment p...

R. L. Liboff

1969-01-01

160

Off-axial plasma displacement suitable for antihydrogen production in AEgIS experiment. An application of (1, 0) diocotron mode excitation in low magnetic fields  

NASA Astrophysics Data System (ADS)

Antihydrogen experiments are currently based on non neutral electron, positron or antiproton plasma manipulation techniques in cylindrical Malmberg-Penning traps. An experimental study of a plasma manipulation technique based on off-axis diocotron displacement is presented. The use of the autoresonant excitation of (1, 0) diocotron mode of pure electron plasma allows a precise positioning of the plasma by moving it across the magnetic field and allows dumping such plasma in a desired angular position. The experimental procedure described here will pave the way to positron loading into an off-axial Penning trap terminated with a positronium converter target as it is proposed for the AEgIS experimental apparatus. The technique was studied over a range of confining magnetic field values and reproduces experimental conditions similar to most of the currently running antihydrogen experiments. The efficiency of the autoresonant excitation - in terms of plasma expansion rate and particle loss - is analyzed, studying the behaviour of electron plasma subjected to large off-axial displacements, showing that this method fulfills the requirements imposed by the AEgIS experiment.

Canali, C.; Carraro, C.; Krasnicky, D.; Lagomarsino, V.; di Noto, L.; Testera, G.; Zavatarelli, S.

2011-12-01

161

Fracture surface interference in shear. 2: Experimental measurements of crack tip displacement field under Mode II loading in 7075-T6 Al  

SciTech Connect

The in-plane and out-of-plane displacement field around the tip of a crack (produced by Mode I fatigue precracking) loaded in pure, remote Mode II was measured as a function of K{sub IIapp} by electro-optic holographic interferometry. The effective Mode II stress intensity factor and the induced Mode I stress intensity factor were estimated from a fit to the near-tip expressions for the crack face displacement fields. The effective Mode II stress intensity factor was always less than the applied stress intensity factor demonstrating that the fracture surface asperities shield the crack tip. The induced Mode I stress intensity factor was roughly half that of the applied Mode II stress intensity factor, demonstrating that pure Mode II cracks cannot be obtained for cracks with microscopically rough surfaces. Plateaus and jumps in the dependence of the effective Mode II and induced Mode I stress intensity factor on the applied Mode II were correlated further supporting the notion that the fracture surface interference is based on asperity interactions. Analysis of the data shows that force transfer across the crack faces cannot be simply described by a frictional interaction across the asperities. It is suggested that deformation of the asperities must be considered to accurately model the shielding and induced crack face opening under remote Mode II loading.

Gross, T.S.; Watt, D.W. [Univ. of New Hampshire, Durham, NH (United States). Dept. of Mechanical Engineering; Zhang, Y. [Limco Manufacturing Corp., Glen Cove, NY (United States)

1995-03-01

162

RTV 21 Displacements  

SciTech Connect

A seal is needed for the cover of the Nitrogen Test Vessel in order to prevent leakage of the N{sub 2} gas. This seal is to be molded out of RTV 21. In this experiment, the Modulus of Elasticity of the RTV was sought after, and the displacements of the RTV due to various stresses were measured to see if they were large enough to provide a tight seal between the vessel and its cover.

Kurita, C.H.; /Fermilab

1987-02-04

163

Polarization of Charged Particles due to Radiation of Slow Waves in the External Magnetic Field  

NASA Astrophysics Data System (ADS)

Results of investigation of the interaction of charged particles with spin 1/2 moving in the external uniform magnetic field with slow electromagnetic waves of the helix wave guide are presented. The transfer of particles along Landau levels due to emitting and absorbing of slow electromagnetic waves in the regions of anomalous (ADE) and normal (NDE) Doppler effects is studied. Processes involving spin flip are considered. It is demonstrated that under spontaneous radiation in the region of ADE polarization of particles is possible. Complex Doppler effect (involving quantum kick) is studied. It is demonstrated that polarization of charged particles due to induced radiation is possible in this case.

Buts, V. A.; Buts, A. V.; Ivanov, B. I.; Manuilenko, O. V.

1997-05-01

164

EVALUATION OF THE COMPRESSIVE RESPONSE OF NOTCHED COMPOSITE PANELS USING A FULL-FIELD DISPLACEMENT MEASUREMENT SYSTEM  

Microsoft Academic Search

Abstract An experimental and analytical evaluation of the compressive response of two composite, notched stiffened panels representative of primary composite wing structure is presented. A three-dimensional full-field image correlation technique is

David M. McGowan; Damodar R. Ambur; T. Glen Hanna; Stephen R. McNeill

1999-01-01

165

Observation of megagauss-field topology changes due to magnetic reconnection in laser-produced plasmas.  

PubMed

The spatial structure and temporal evolution of megagauss magnetic fields generated by interactions of up to 4 laser beams with matter were studied with an innovative, time-gated proton radiography method that produces images of unprecedented clarity because it uses an isotropic, truly monoenergetic back-lighter (14.7-MeV protons from D3He nuclear fusion reactions). Quantitative field maps reveal precisely and directly, for the first time, changes in the magnetic topology due to reconnection in a high-energy-density plasma (n(e) approximately 10(20)-10(22) cm(-3), T(e) approximately 1 keV). PMID:17930762

Li, C K; Séguin, F H; Frenje, J A; Rygg, J R; Petrasso, R D; Town, R P J; Landen, O L; Knauer, J P; Smalyuk, V A

2007-08-02

166

Wavelet denoising of displacement estimates in elastography  

Microsoft Academic Search

Wavelet shrinkage denoising of the displacement estimates to reduce noise artefacts, especially at high overlaps in elastography, is presented in this paper. Correlated errors in the displacement estimates increase dramatically with an increase in the overlap between the data segments. These increased correlated errors (due to the increased correlation or similarity between consecutive displacement estimates) generate the so-called “worm” artefact

Udomchai Techavipoo; Tomy Varghese

2004-01-01

167

Temperature fields in a liquid due to the thermocapillary motion of bubbles and drops  

Microsoft Academic Search

Experiments were performed on the motion of isolated air bubbles and drops of Fluorinert FC-75 moving in a Dow-Corning silicone\\u000a oil under the action of an applied temperature gradient in a reduced gravity environment aboard the Space Shuttle in orbit.\\u000a The disturbance of the imposed temperature field due to the motion of the objects was studied optically using a shearing

G. Wozniak; R. Balasubramaniam; P. H. Hadland; R. S. Subramanian

2001-01-01

168

Noninversive partial velocity amplification of radiation by ions due to their rotation in a magnetic field  

Microsoft Academic Search

It is shown that upon the application of an external magnetic field, a gas of ionized particles may experience noninversive\\u000a partial velocity amplification of radiation by ions due to their Larmor rotation. In this case, virtually all ions may be\\u000a in the ground state. It may happen that approximately half the number of ions in the medium amplify the incident

A. I. Parkhomenko

2002-01-01

169

Displacement in Revitalizing Neighborhoods: A Review and Research Strategy. (RE-ANNOUNCEMENT of PB85-126829-see notes field for explanation).  

National Technical Information Service (NTIS)

This paper first provides an analytical framework for viewing the displacement of poor families within the larger context of neighborhood revitalization and then reviews existing evidence to assess what is known about displacement's magnitude and extent; ...

H. J. Sumka

1979-01-01

170

Field collapse due to band-tail charge in amorphous silicon solar cells  

SciTech Connect

It is common for the fill factor to decrease with increasing illumination intensity in hydrogenated amorphous silicon solar cells. This is especially critical for thicker solar cells, because the decrease is more severe than in thinner cells. Usually, the fill factor under uniformly absorbed red light changes much more than under strongly absorbed blue light. The cause of this is usually assumed to arise from space charge trapped in deep defect states. The authors model this behavior of solar cells using the Analysis of Microelectronic and Photonic Structures (AMPS) simulation program. The simulation shows that the decrease in fill factor is caused by photogenerated space charge trapped in the band-tail states rather than in defects. This charge screens the applied field, reducing the internal field. Owing to its lower drift mobility, the space charge due to holes exceeds that due to electrons and is the main cause of the field screening. The space charge in midgap states is small compared with that in the tails and can be ignored under normal solar-cell operating conditions. Experimentally, the authors measured the photocapacitance as a means to probe the collapsed field. They also explored the light intensity dependence of photocapacitance and explain the decrease of FF with the increasing light intensity.

Wang, Qi; Crandall, R.S. [National Renewable Energy Lab., Golden, CO (United States); Schiff, E.A. [Syracuse Univ., NY (United States)

1996-05-01

171

Effects of spatial confinement of electromagnetic field on optical forces due to whispering-gallery modes  

NASA Astrophysics Data System (ADS)

Using ab initio approach to the theory of electromagnetic interaction of a small particle and spherical whispering gallery mode resonator, we derive the optical forces experienced by the particle and it's resulting motion. The form of the forces differs from that expected by the traditional gradient/scattering approach due to the modification of the field by the particle. The main effect of the confinement of the field in a cavity consists in making the component of the optical force usually interpreted as gradient, manifestly non-conservative, and hence not presentable in the gradient form. It is shown how the standard gradient/scattering formalism can be modified for the cavity confined optical field.

Rubin, J. T.; Deych, L.

2012-02-01

172

Additional enhancement of electric field in surface-enhanced Raman Scattering due to Fresnel mechanism.  

PubMed

Surface-enhanced Raman scattering (SERS) is attracting increasing interest for chemical sensing, surface science research and as an intriguing challenge in nanoscale plasmonic engineering. Several studies have shown that SERS intensities are increased when metal island film substrates are excited through a transparent base material, rather than directly through air. However, to our knowledge, the origin of this additional enhancement has never been satisfactorily explained. In this paper, finite difference time domain modeling is presented to show that the electric field intensity at the dielectric interface between metal particles is higher for "far-side" excitation than "near-side". This is reasonably consistent with the observed enhancement for silver islands on SiO2. The modeling results are supported by a simple analytical model based on Fresnel reflection at the interface, which suggests that the additional SERS signal is caused by near-field enhancement of the electric field due to the phase shift at the dielectric interface. PMID:23903714

Jayawardhana, Sasani; Rosa, Lorenzo; Juodkazis, Saulius; Stoddart, Paul R

2013-01-01

173

Studies in space orientation. II. Perception of the upright with displaced visual fields and with body tilted  

Microsoft Academic Search

The S was presented with a small tilted room, on the back wall of which was a rod which he had to adjust to the true upright. In a first test, judgments of the rod were obtained with body upright, and under three different conditions of the field: (a) The S, standing at a distance from the tilted scene, viewed

S. E. Asch; H. A. Witkin

1948-01-01

174

Neural Control of Visual Search by Frontal Eye Field: Effects of Unexpected Target Displacement on Visual Selection and Saccade Preparation  

PubMed Central

The dynamics of visual selection and saccade preparation by the frontal eye field was investigated in macaque monkeys performing a search-step task combining the classic double-step saccade task with visual search. Reward was earned for producing a saccade to a color singleton. On random trials the target and one distractor swapped locations before the saccade and monkeys were rewarded for shifting gaze to the new singleton location. A race model accounts for the probabilities and latencies of saccades to the initial and final singleton locations and provides a measure of the duration of a covert compensation process—target-step reaction time. When the target stepped out of a movement field, noncompensated saccades to the original location were produced when movement-related activity grew rapidly to a threshold. Compensated saccades to the final location were produced when the growth of the original movement-related activity was interrupted within target-step reaction time and was replaced by activation of other neurons producing the compensated saccade. When the target stepped into a receptive field, visual neurons selected the new target location regardless of the monkeys’ response. When the target stepped out of a receptive field most visual neurons maintained the representation of the original target location, but a minority of visual neurons showed reduced activity. Chronometric analyses of the neural responses to the target step revealed that the modulation of visually responsive neurons and movement-related neurons occurred early enough to shift attention and saccade preparation from the old to the new target location. These findings indicate that visual activity in the frontal eye field signals the location of targets for orienting, whereas movement-related activity instantiates saccade preparation.

Murthy, Aditya; Ray, Supriya; Shorter, Stephanie M.; Schall, Jeffrey D.; Thompson, Kirk G.

2009-01-01

175

Displacement of Biomphalaria glabrata by the snail Thiara granifera in field habitats in St. Lucia, West Indies.  

PubMed

Thiara granifera is a melaniid snail capable of maintaining very high densities in a variety of habitats. It has been introduced into the New World from the Far East and is now spreading rapidly throughout the Caribbean. In Puerto Rico and Dominica casual observations following natural invasion by T. granifera suggest that it may exert a powerful restraining influence on populations of Biomphalaria glabrata, the major intermediate host of Schistosoma mansoni in the Caribbean. The potential of T. granifera in biological control is being investigated in St. Lucia. In four field trials, B. glabrata was apparently eliminated from marshes and streams six to 22 months after the introduction of T. granifera. Thiara granifera shows promise as a major factor in the suppression of schistosomiasis in the Caribbean, but it is unsuitable for universal use as it is an intermediate host of the lung fluke, Paragonimus westermani. PMID:6882056

Prentice, M A

1983-02-01

176

Improved confinement due to open ergodic field lines imposed by the dynamic ergodic divertor in TEXTOR.  

PubMed

The ergodization of the magnetic field lines imposed by the dynamic ergodic diverter (DED) in TEXTOR can lead both to confinement improvement and to confinement deterioration. The cases of substantial improvement are in resonant ways related to particular conditions in which magnetic flux tubes starting at the X points of induced islands are connected with the wall. This opening process is connected with a characteristic modification of the heat deposition pattern at the divertor target plate and leads to a substantial increase and steepening of the core plasma density and pressure. The improvement is tentatively attributed to a modification of the electric potential in the plasma carried by the open field lines. The confinement improvement bases on a spontaneous density built up due to the application of the DED and is primarily a particle confinement improvement. PMID:17358951

Finken, K H; Abdullaev, S S; Jakubowski, M W; de Bock, M F M; Bozhenkov, S; Busch, C; von Hellermann, M; Jaspers, R; Kikuchi, Y; Krämer-Flecken, A; Lehnen, M; Schega, D; Schmitz, O; Spatschek, K H; Unterberg, B; Wingen, A; Wolf, R C; Zimmermann, O

2007-02-05

177

A Solution of the Einstein Equation in a Stationary Gravitational Field Due to a Rotating Source  

NASA Astrophysics Data System (ADS)

The stationary and axially symmetric gravitational field due to a rotating deformed source can be treated by the Ernst equation. We prove analytically the validity of the solution of the Ernst equation that was presented as a possible solution in a previous paper for arbitrary real values of the deformation parameter &delta. By means of analytic continuations of the solution we obtain a new solution in oblate spheroidal coordinates. This leads to a metric different from the Tomimatsu-Sato metric. From these solutions for real &delta we determine the metric functions both in prolate and oblate spheroidal coordinates.

Tanimura, O.; Hori, S.

1999-02-01

178

Dispersive FDTD analysis of induced electric field in human models due to electrostatic discharge.  

PubMed

Contact currents flow from/into a charged human body when touching a grounded conductive object. An electrostatic discharge (ESD) or spark may occur just before contact or upon release. The current may stimulate muscles and peripheral nerves. In order to clarify the difference in the induced electric field between different sized human models, the in-situ electric fields were computed in anatomically based models of adults and a child for a contact current in a human body following ESD. A dispersive finite-difference time-domain method was used, in which biological tissue is assumed to obey a four-pole Debye model. From our computational results, the first peak of the discharge current was almost identical across adult and child models. The decay of the induced current in the child was also faster due mainly to its smaller body capacitance compared to the adult models. The induced electric fields in the forefingers were comparable across different models. However, the electric field induced in the arm of the child model was found to be greater than that in the adult models primarily because of its smaller cross-sectional area. The tendency for greater doses in the child has also been reported for power frequency sinusoidal contact current exposures as reported by other investigators. PMID:22713253

Hirata, Akimasa; Nagai, Toshihiro; Koyama, Teruyoshi; Hattori, Junya; Chan, Kwok Hung; Kavet, Robert

2012-06-20

179

Field and laboratory tests on risk of slope failure due to weathering of rock materials  

NASA Astrophysics Data System (ADS)

Authors set out the challenge to explore the mechanism of rock weathering and its effects to the geotechnical hazards. Any natural or human induced disturbances to the natural slopes speed up their weathering process. So, exploration of both disturbed and undisturbed slopes is necessary for robust understanding. Various regions in Asia were explored to experience variety of environmental and climatic conditions. Field exploration on the thickness and in-situ mechanical property was carried out by performing seismic refraction surveys, dynamic cone penetration tests and Schmidt hammer tests at various sites in Japan and Pakistan. In laboratory change in mechanical property of soft rocks due to weathering has been observed and slake durability tests were conducted on various rocks. Field exploration indicated that the thickness of weathered layer is 1 meter or its roundabouts and having S-wave velocity of 200-300 m/s. Laboratory testing differentiated the slaking potential and mechanical property degradation of various rocks. Moreover sensible correlations had been observed in thickness calculated by seismic refraction or dynamic cone penetration in field. Slake durability index showed good correlation with Schmidt hammer hardness and mechanical property. A general agreement was also observed when strength and S-wave velocities from laboratory tests were compared with the field exploration. Authors believed that the study provides the useful information on the long term prediction and assessment of landslide risk.

Qureshi, M. U.; Towhata, I.; Yamada, S.; Aziz, M.

2009-04-01

180

Porous silicon/Ni composites of high coercivity due to magnetic field-assisted etching  

PubMed Central

Ferromagnetic nanostructures have been electrodeposited within the pores of porous silicon templates with average pore diameters between 25 and 60?nm. In this diameter regime, the pore formation in general is accompanied by dendritic growth resulting in rough pore walls, which involves metal deposits also offering a branched structure. These side branches influence the magnetic properties of the composite system not only due to modified and peculiar stray fields but also because of a reduced interpore spacing by the approaching of adjacent side pores. To improve the morphology of the porous silicon structures, a magnetic field up to 8?T has been applied during the formation process. The magnetic field etching results in smaller pore diameters with less dendritic side pores. Deposition of a ferromagnetic metal within these templates leads to less branched nanostructures and, thus, to an enhancement of the coercivity of the system and also to a significantly increased magnetic anisotropy. So magnetic field-assisted etching is an appropriate tool to improve the structure of the template concerning the decrease of the dendritic pore growth and to advance the magnetic properties of the composite material.

2012-01-01

181

Magnetic Field Shift due to Mechanical Vibration in Functional Magnetic Resonance Imaging  

PubMed Central

Mechanical vibrations of the gradient coil system during readout in echo-planar imaging (EPI) can increase the temperature of the gradient system, and alter the magnetic field distribution during functional magnetic resonance imaging (fMRI). This effect is enhanced by resonant modes of vibrations and results in apparent motion along the phase encoding direction in fMRI studies. The magnetic field drift was quantified during EPI, by monitoring the resonance frequency interleaved with the EPI acquisition, and a novel method is proposed to correct the apparent motion. The knowledge on the frequency drift over time was used to correct the phase of the k-space EPI dataset. Since the resonance frequency changes very slowly over time, two measurements of the resonance frequency, immediately before and after the EPI acquisition, are sufficient to remove the field drift effects from fMRI time series. The frequency drift correction method was tested “in vivo” and compared to the standard image realignment method. The proposed method efficiently corrects spurious motion due to magnetic field drifts during fMRI.

Foerster, Bernd U.; Tomasi, Dardo; Caparelli, Elisabeth C.

2008-01-01

182

Laser front distortions due to flow field around a helicopter configuration on hover and forward motion  

NASA Astrophysics Data System (ADS)

Laser beam front distortions characterizing near field losses of energy from a turret mounted on a generic helicopter have been computed to support the modeling and simulation effort of a directed energy testing. The flow field has been computed using an unstructured computational fluid dynamics method with (a) Reynolds averaged Navier-Stokes method with Spalart-Almaras (SA) turbulence model and (b) time accurate Detached Eddy Simulation with SA turbulence model. The beam distortions have been computed using an aero-optics model developed at the University of Notre Dame. For study (a), the rotor surface is modeled by an actuator disk with a jump in the pressure at the disk plane with the laser passing through the flow field due to the fuselage and the rotor. In the case of study (b), the laser is passing through a time accurate flow field of an isolated rotor blade. The laser front distortions, computed through optical path differences for several azimuth and elevation angles for hover and forward flight conditions, are presented in this study.

Dodbele, Simha

2009-11-01

183

Large-scale magnetic fields from inflation due to a CPT-even Chern-Simons-like term with Kalb-Ramond and scalar fields  

NASA Astrophysics Data System (ADS)

We investigate the generation of large-scale magnetic fields due to the breaking of the conformal invariance in the electromagnetic field through the CPT-even dimension-six Chern-Simons-like effective interaction with a fermion current by taking account of the dynamical Kalb-Ramond and scalar fields in inflationary cosmology. It is explicitly demonstrated that magnetic fields on 1 Mpc scale with the field strength of ˜10-9 G at the present time can be induced.

Bamba, Kazuharu; Geng, C. Q.; Ho, S. H.; Kao, W. F.

2012-04-01

184

Computer simulation of electric field variations due to movements of electric charges.  

PubMed

Simulations were carried out for the orbit of electron-induced secondary electrons around a charged microfibril of a sciatic nerve tissue. In order to set the parameters for the simulation, the shape of the microfibril was determined from a transmission electron microscopy image, while the electric potential on the surface of the charged microfibril was evaluated from a reconstructed phase image obtained with electron holography. On the other hand, the passing point and the angle of secondary electrons at the microfibril surface were determined from a reconstructed amplitude image. Eventually, simulation of orbits of secondary electrons was carried out by changing the kinetic energy of the secondary electrons. Under the given conditions, the orbit of secondary electrons with a kinetic energy of 29.6 eV fits the observations. If there are thin layers of electrons, the secondary electrons do not reach the surface but they go over it due to the repulsive Coulomb force resulting in successive revolving motion around the charged microfibril. Furthermore, the electric field variation due to the movement of the electric charges resulting from the specimen drift is also discussed briefly comparing it with electron holography data. PMID:22595205

Inoue, Masao; Suzuki, Satoshi; Akase, Zentaro; Shindo, Daisuke

2012-05-16

185

Enhancement and decrease of critical current due to suppression of superconductivity by a magnetic field  

NASA Astrophysics Data System (ADS)

We present experimental results on the transport properties of a superconducting aluminum loop connected to reservoirs. As function of the applied magnetic field, an unexpected behavior is found—a steep enhancement (for temperatures close to the critical temperature) and a sharp drop (at lower temperatures) of the critical current at some value of the magnetic field Ba*(T) . These effects are a consequence of a sudden suppression of superconductivity at Ba=Ba* in the banks to which the loop is attached by the current leads. As a result, the normal metal-superconductor boundaries appear at the ends of the current leads and the quasiparticle distribution function f(E) in the superconductor deviates strongly from its equilibrium value. Calculations based on the Usadel equations show that the critical current should be enhanced at high temperature (due to the penetration of the normal current from the normal metal-superconductor boundaries), whereas at low temperatures, the suppression of the order parameter by the nonequilibrium f(E) dominates and the critical current decreases. The latter provides a direct experimental verification of the recently proposed mechanism of the destruction of superconductivity by an applied voltage [R. S. Keizer, M. G. Flokstra, J. Aarts, and T. M. Klapwijk, Phys. Rev. Lett. 96, 147002 (2006)].

Vodolazov, D. Y.; Golubovi?, D. S.; Peeters, F. M.; Moshchalkov, V. V.

2007-10-01

186

Solar Wind Slowdown Due to Dust Pickup during Interplanetary Field Enhancements  

NASA Astrophysics Data System (ADS)

The interplanetary field enhancements (IFEs) are characterized by their cusp-shaped enhancement in the magnetic field magnitude. They are observed throughout the inner solar system from 0.72AU by Pioneer Venus Orbiter to 5AU by Ulysses. The annual IFE rate is ten at 0.72AU and around eight at 1AU, i.e., decreases as the heliocentric distance increases. Multiple-spacecraft observations show that IFEs are moving radially away from the Sun at nearly the ambient solar wind speed. During the IFE events, case studies show that while there are correlated diamagnetic compensations in pressure there are no significant correlated changes in the solar wind speed. An IFE formation mechanism that explains most of the IFE features is that IFEs result from interactions between solar wind and clouds of picked up nanoscale charged dust, which is released in interplanetary collisions between objects of 10 to 1000m in diameter. The enhanced magnetic field behaves as a magnetic barrier that can transfer momentum to the charged dust from the solar wind. Momentum lifts the dust outward in the solar gravitational well. A prediction of this hypothesis is that solar wind will be slowed down even when the IFEs have reached exactly the solar wind speed. To test this hypothesis, we perform a superposed analysis on the radial velocity of IFEs observed at 1AU. In contrast to the case studies, the statistical results have a significant change in speed. The velocity on the solar wind side of the IFEs is smaller than the ambient velocity. This slowdown increases for larger IFEs with larger estimated mass. In addition, the amount of momentum due to the solar wind slowdown is quantitatively consistent with the momentum expected to be needed to lift the dust out of the Sun's gravitational potential well, which is in strong support of our IFE formation mechanism.

Lai, Hairong; Russell, Christopher; Wei, Hanying

2013-04-01

187

Fuel Efficient Stoves for Darfur Camps of Internally Displaced Persons: Report of Field Trip to North and South Darfur, November 16-December 17, 2005.  

National Technical Information Service (NTIS)

Approximately 2.2 million internally displaced persons (''IDPs'') in Darfur are living in dense camps scattered in arid areas with low fuelwood productivity. Unsustainable harvesting of fuelwood by the IDPs has created ever increasing zones of denudation,...

C. Galitsky A. Gadgil M. Jacobs Y. M. Lee

2006-01-01

188

Computation of the induced current density into the human body due to relative LF magnetic field generated by realistic devices  

Microsoft Academic Search

A three-dimensional finite-element formulation to compute induced currents into the human body due to relative low-frequency magnetic field is described. Magnetic source field and induced currents are computed separately, allowing to handle sources due to realistic devices. This method is validated using analytical solutions over a sphere. The limit of validity of the formulation is established. Computations using an accurate

Riccardo Scorretti; Noël Burais; Olivier Fabregue; Alain Nicolas; Laurent Nicolas

2004-01-01

189

FARADAY ROTATION MEASURE DUE TO THE INTERGALACTIC MAGNETIC FIELD. II. THE COSMOLOGICAL CONTRIBUTION  

SciTech Connect

We investigate the Faraday rotation measure (RM) due to the intergalactic magnetic field (IGMF) through the cosmic web up to cosmological distances, using a model IGMF based on turbulence dynamo in the large-scale structure of the universe. By stacking the IGMF and gas density data up to redshift z = 5 and taking account of the redshift distribution of polarized background radio sources against which the RM is measured, we simulate the sky map of the RM. The contribution from galaxy clusters is subtracted from the map, based on several different criteria of X-ray brightness and temperature. Our findings are as follows. The distribution of RM for radio sources of different redshifts shows that the rms value increases with redshift and saturates for z {approx}> 1. The saturated value is RM{sub rms} {approx} several rad m{sup -2}. The probability distribution function of |RM| follows the lognormal distribution. The power spectrum has a broad plateau over the angular scale of {approx}1{sup 0}-0.{sup 0}1 with a peak around {approx}0.{sup 0}15. The second-order structure function has a flat profile in the angular separation of {approx}> 0.{sup 0}2. Our results could provide useful insights for surveys to explore the IGMF with the Square Kilometer Array (SKA) and upcoming SKA pathfinders.

Akahori, Takuya [Research Institute of Basic Science, Chungnam National University, Daejeon (Korea, Republic of); Ryu, Dongsu, E-mail: akataku@canopus.cnu.ac.kr, E-mail: ryu@canopus.cnu.ac.kr [Department of Astronomy and Space Science, Chungnam National University, Daejeon (Korea, Republic of)

2011-09-10

190

Pattern orientation due to longitudinal fields in a cavity with Kerr media  

NASA Astrophysics Data System (ADS)

When describing field propagation in a ring cavity, longitudinal fields are usually neglected. Although small, the longitudinal component is always present in finite width beams. An equation describing field propagation in Kerr media and inside a ring cavity filled with such medium is derived. Coupling among longitudinal and transverse fields but also other usually neglected terms are considered. Numerical integration results show that coupling with longitudinal field can orientate the resulting pattern along the polarization direction.

Mártin, Daniel A.

2013-08-01

191

A Methodology to Validate the InSAR Derived Displacement Field of the September 7th, 1999 Athens Earthquake Using Terrestrial Surveying. Improvement of the Assessed Deformation Field by Interferometric Stacking  

PubMed Central

The primary objective of this paper is the evaluation of the InSAR derived displacement field caused by the 07/09/1999 Athens earthquake, using as reference an external data source provided by terrestrial surveying along the Mornos river open aqueduct. To accomplish this, a processing chain to render comparable the leveling measurements and the interferometric derived measurements has been developed. The distinct steps proposed include a solution for reducing the orbital and atmospheric interferometric fringes and an innovative method to compute the actual InSAR estimated vertical ground subsidence, for direct comparison with the leveling data. Results indicate that the modeled deformation derived from a series of stacked interferograms, falls entirely within the confidence interval assessed for the terrestrial surveying data.

Kotsis, Ioannis; Kontoes, Charalabos; Paradissis, Dimitrios; Karamitsos, Spyros; Elias, Panagiotis; Papoutsis, Ioannis

2008-01-01

192

Distortion of magnetic field and magnetic force of a brushless dc motor due to deformed rubber magnet  

Microsoft Academic Search

This paper investigates the distortion of magnetic field of a brushless dc (BLDC) motor due to deformed rubber magnet. Global or local deformation of rubber magnet in the BLDC motor is mathematically modeled by using the Fourier series. Distorted magnetic field is calculated by using the finite element method, and unbalanced magnetic force is calculated by using the Maxwell stress

C. J. Lee; G. H. Jang

2008-01-01

193

The effect of space charge fields due to finite length electron beams in the free-electron laser  

Microsoft Academic Search

The space charge electric field of a finite length electron beam in the free electron laser amplifier with a tapered wiggler is analyzed. In the free drift region between the accelerator and laser, expressions for the increase of energy spread due to the self field are presented. In the FEL interaction region, the general conditions on the importance of the

C.-M. Tang; P. Sprangle; H. Freund; W. Colson

1982-01-01

194

Wake fields of a bunch on a general trajectory due to coherent synchrotron radiation  

Microsoft Academic Search

If short bunches travel along trajectories with small bending radii a simple geometrical condition permits strong longitudinal and radial wake fields to act: electromagnetic fields emitted by a particle can `overtake' on a shelter straight trajectory and interact with particles ahead. The bunch then starts to radiate coherently. The electromagnetic fields along the bunch have strong gradients and in general

Martin Dohlus; A. Kabel; T. Limberg

1997-01-01

195

WAKE FIELDS OF A BUNCH ON A GENERAL TRAJECTORY DUE TO COHERENT SYNCHROTRON RADIATION  

Microsoft Academic Search

If short bunches travel along trajectories with small bend- ing radii a simple geometrical condition permits strong lon- gitudinal and radial wake fields to act: electromagnetic fields emitted by a particle can 'overtake' on a shorter straight trajectory and interact with particles ahead. The bunch then starts to radiate coherently. The electromag- netic fields along the bunch have strong gradients

M. Dohlus; A. Kabel; T. Limberg

1998-01-01

196

Generation of magnetic seed fields in protogalactic clouds due to plasma-neutral gas friction  

Microsoft Academic Search

We show that plasma - neutral gas friction in a weakly ionized rotating protogalactic system creates magnetic fields of seed field order. For these purposes we present results of 2-fluid simulations. Considering primordial gas clouds, this mechanism yields a magnetic field of the order of 10(-15) G on time scales of 10(6) yr and spatial scales of several hundred parsec.

H. Wiechen; G. T. Birk; H. Lesch

1998-01-01

197

Potato yield losses due to early blight in Minnesota fields, 1981 and 1982  

Microsoft Academic Search

In both 1981 and 1982, 51 potato fields were surveyed every 7–10 days for early blight severity and fungicide use. Early blight\\u000a severity data from each field were used as input to a regression model to estimate yield loss in that field. The model for\\u000a early maturing potato cultivars was Percent Yield Loss=0.8183+0.6441* (% blight increment between days 56 and

P. S. Teng; H. L. Bissonnette

1985-01-01

198

Precision displacement reference system  

DOEpatents

A precision displacement reference system is described, which enables real time accountability over the applied displacement feedback system to precision machine tools, positioning mechanisms, motion devices, and related operations. As independent measurements of tool location is taken by a displacement feedback system, a rotating reference disk compares feedback counts with performed motion. These measurements are compared to characterize and analyze real time mechanical and control performance during operation.

Bieg, Lothar F. (Albuquerque, NM); Dubois, Robert R. (Albuquerque, NM); Strother, Jerry D. (Edgewood, NM)

2000-02-22

199

Large scale alignments in quasar polarizations due to pseudoscalar-photon mixing in intergalactic magnetic fields  

Microsoft Academic Search

We consider the propagation of visible radiation from quasars located at cosmological distances in intergalactic space, taking pseudoscalar-photon mixing into account. We assume that the intergalactic magnetic field is uncorrelated in the wave vector space such that the two point correlation function shows a power dependence on the magnitude of the wave vector. This leads to correlated magnetic field in

Nishant Agarwal; Pavan K. Aluri; Pankaj Jain; Udit Khanna; Prabhakar Tiwari

2011-01-01

200

Electromagnetic fields in the human body due to switched transverse gradient coils in MRI  

NASA Astrophysics Data System (ADS)

Magnetic resonance imaging scans impose large gradient magnetic fields on the patient. Modern imaging techniques require this magnetic field to be switched rapidly for good resolution. However, it is believed that this can also lead to the unwanted side effect of peripheral nerve stimulation, which proves to be a limiting factor to the advancement of MRI technology. This paper establishes an analytical model for the fields produced within an MRI scanner by transverse gradient coils of known current density. Expressions are obtained for the magnetic induction vector and the electric field vector, as well as for the surface charge and current densities that are induced on the patient's body. The expressions obtained are general enough to allow the study of any combination of gradient coils whose behaviour can be approximated by Fourier series. For a realistic example coil current density and switching function, it is found that spikes of surface charge density are induced on the patient's body as the gradient field is switched, as well as loops of surface current density that mimic the coil current density. For a 10 mT m-1 gradient field with a rise time of 100 µs, the magnitude of the radial electric field at the body is found to be 10.3 V m-1. It is also found that there is a finite limit to radial electric field strength as rise time approaches zero.

While, Peter T.; Forbes, Larry K.

2004-07-01

201

Electromagnetic fields in the human body due to switched transverse gradient coils in MRI  

Microsoft Academic Search

Magnetic resonance imaging scans impose large gradient magnetic fields on the patient. Modern imaging techniques require this magnetic field to be switched rapidly for good resolution. However, it is believed that this can also lead to the unwanted side effect of peripheral nerve stimulation, which proves to be a limiting factor to the advancement of MRI technology. This paper establishes

Peter T While; Larry K Forbes

2004-01-01

202

Heating in the MRI environment due to superparamagnetic fluid suspensions in a rotating magnetic field  

NASA Astrophysics Data System (ADS)

In the presence of alternating-sinusoidal or rotating magnetic fields, magnetic nanoparticles will act to realign their magnetic moment with the applied magnetic field. The realignment is characterized by the nanoparticle's time constant, ?. As the magnetic field frequency is increased, the nanoparticle's magnetic moment lags the applied magnetic field at a constant angle for a given frequency, ?, in rad/s. Associated with this misalignment is a power dissipation that increases the bulk magnetic fluid's temperature which has been utilized as a method of magnetic nanoparticle hyperthermia, particularly suited for cancer in low-perfusion tissue (e.g., breast) where temperature increases of between 4 and 7 degree Centigrade above the ambient in vivo temperature cause tumor hyperthermia. This work examines the rise in the magnetic fluid's temperature in the MRI environment which is characterized by a large DC field, B0. Theoretical analysis and simulation is used to predict the effect of both alternating-sinusoidal and rotating magnetic fields transverse to B0. Results are presented for the expected temperature increase in small tumors (approximately 1 cm radius) over an appropriate range of magnetic fluid concentrations (0.002-0.01 solid volume fraction) and nanoparticle radii (1-10 nm). The results indicate that significant heating can take place, even in low-field MRI systems where magnetic fluid saturation is not significant, with careful selection of the rotating or sinusoidal field parameters (field frequency and amplitude). The work indicates that it may be feasible to combine low-field MRI with a magnetic hyperthermia system using superparamagnetic iron oxide nanoparticles.

Cantillon-Murphy, P.; Wald, L. L.; Adalsteinsson, E.; Zahn, M.

2010-03-01

203

Heating in the MRI environment due to superparamagnetic fluid suspensions in a rotating magnetic field  

PubMed Central

In the presence of alternating-sinusoidal or rotating magnetic fields, magnetic nanoparticles will act to realign their magnetic moment with the applied magnetic field. The realignment is characterized by the nanoparticle’s time constant, ?. As the magnetic field frequency is increased, the nanoparticle’s magnetic moment lags the applied magnetic field at a constant angle for a given frequency, ?, in rad/s. Associated with this misalignment is a power dissipation that increases the bulk magnetic fluid’s temperature which has been utilized as a method of magnetic nanoparticle hyperthermia, particularly suited for cancer in low-perfusion tissue (e.g., breast) where temperature increases of between 4°C and 7°C above the ambient in vivo temperature cause tumor hyperthermia. This work examines the rise in the magnetic fluid’s temperature in the MRI environment which is characterized by a large DC field, B0. Theoretical analysis and simulation is used to predict the effect of both alternating-sinusoidal and rotating magnetic fields transverse to B0. Results are presented for the expected temperature increase in small tumors (~1 cm radius) over an appropriate range of magnetic fluid concentrations (0.002 to 0.01 solid volume fraction) and nanoparticle radii (1 to 10 nm). The results indicate that significant heating can take place, even in low-field MRI systems where magnetic fluid saturation is not significant, with careful selection of the rotating or sinusoidal field parameters (field frequency and amplitude). The work indicates that it may be feasible to combine low-field MRI with a magnetic hyperthermia system using superparamagnetic iron oxide nanoparticles.

Wald, L.L.; Adalsteinsson, E.; Zahn, M.

2009-01-01

204

Distortion of magnetic field and magnetic force of a brushless dc motor due to deformed rubber magnet  

NASA Astrophysics Data System (ADS)

This paper investigates the distortion of magnetic field of a brushless dc (BLDC) motor due to deformed rubber magnet. Global or local deformation of rubber magnet in the BLDC motor is mathematically modeled by using the Fourier series. Distorted magnetic field is calculated by using the finite element method, and unbalanced magnetic force is calculated by using the Maxwell stress tensor. When the rubber magnet is globally or locally deformed, the unbalanced magnetic force has the frequencies with the first harmonic and the harmonics of slot number +/-1. However, the harmonic deformation with multiple of common divisor of pole and slot does not generate unbalanced magnetic force due to the rotational symmetry.

Lee, C. J.; Jang, G. H.

2008-04-01

205

Generating "superponderomotive" electrons due to a non-wake-field interaction between a laser pulse and a longitudinal electric field.  

PubMed

It is shown that electrons with momenta exceeding the "free electron" limit of m(e)ca(0)(2)/2 can be produced when a laser pulse and a longitudinal electric field interact with an electron via a non-wake-field mechanism. The mechanism consists of two stages: the reduction of the electron dephasing rate ? - p(x)/m(e)c by an accelerating region of electric field and electron acceleration by the laser via the Lorentz force. This mechanism can, in principle, produce electrons that have longitudinal momenta that is a significant multiple of m(e)ca(0)(2)/2. 2D particle-in-cell simulations of a relatively simple laser-plasma interaction indicate that the generation of superponderomotive electrons is strongly affected by this "antidephasing" mechanism. PMID:23971580

Robinson, A P L; Arefiev, A V; Neely, D

2013-08-05

206

Acoustic phonon tunneling and heat transport due to evanescent electric fields.  

PubMed

The authors describe how acoustic phonons can directly tunnel through vacuum and, therefore, transmit energy and conduct heat between bodies that are separated by a vacuum gap. This effect is enabled by introducing a coupling mechanism, such as piezoelectricity, that strongly couples electric field and lattice deformation. The electric field leaks into the vacuum as an evanescent field, which leads to finite solid-vacuum-solid transmission probability. Because of strong resonances in the system, some phonons can go through the vacuum gap with (or close to) unity transmission, which leads to significant thermal conductance and heat flux. PMID:20867653

Prunnila, Mika; Meltaus, Johanna

2010-09-14

207

Wake fields effects due to surface roughness in a circular pipe  

NASA Astrophysics Data System (ADS)

The problem of the wake field generated by a relativistic particle travelling in a long beam pipe with rough surface has been studied by means of a standard theory based on the hybrid modes excited in a periodically corrugated waveguide with circular cross-section. Slow waves synchronous with the particle can be excited in the structure, producing wake fields whose frequency and amplitude depend on the depth of the corrugation. An analytical expression of the wake field is given for very small corrugations.

Angelici, M.; Frezza, F.; Mostacci, A.; Palumbo, L.

2002-08-01

208

Evaluation of interactions of electric fields due to electrostatic discharge with human tissue.  

PubMed

Electrostatic discharges (ESDs) produce in the human tissue very strong electric fields of short duration. Possible biophysical interactions are evaluated by comparing the fields in subcutaneous fat/skin to the thresholds for peripheral nerve stimulation, and by computations of membrane potential and electric fields in cytoplasm of a typical cell in bone marrow. It is found that a 4-A peak ESD event is capable of stimulation of nerves located in subcutaneous fat of the lower arm of the hand eliciting a spark, with tens of kV/m and pulse duration of approximately 80 ns. For the same ESD event, the transmembrane potential (TMP) reaches 32 mV with a pulse duration of approximately 200 ns (half-width duration). The electric field in the cytoplasm of a bone marrow cell changes from about 8.8 kV/m to--2 kV/m in about 200 ns. PMID:15605868

Dawson, T W; Stuchly, M A; Kavet, R

2004-12-01

209

Origin of Magnetic Fields in the Universe due to Nonminimal Gravitational-Electromagnetic Coupling  

SciTech Connect

Basically the only existing theories for the creation of a magnetic field ({ital B}) in the Universe are the creation of a seed field {approximately}10{sup -20} G in spiral galaxy which is subsequently supposedly amplified up to the observed 10{sup -6}{endash}10{sup -5} G by a dynamo process or a seed intergalactic field of {approximately}10{sup -12}{endash} 10{sup -10} G which is amplified by collapse and differential rotation. No satisfactory dynamo theory, however, exists today. We show that a {approximately}10{sup -6}{endash} 10{sup -5} G magnetic field in spiral galaxies is directly obtained from a nonminimal gravitational-electromagnetic coupling, without the need of significant dynamo amplification. {copyright} {ital 1997} {ital The American Physical Society}

Opher, R. [Instituto de Astronomia e Geofisica, Universidade de Sao Paulo, Av.Miguel Stefano, 4.200, CEP 04301-904, Sao Paulo, SP (Brazil); Wichoski, U.F. [Department of Physics, Brown University, Providence, Rhode Island 02912 (United States); Wichoski, U.F. [Depto.Fisica-Matematica, Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, CEP 05389-970, Sao Paulo, SP (Brazil)

1997-02-01

210

Radiation Field in Air Due to Distributed Gamma-Ray Sources in the Ground.  

National Technical Information Service (NTIS)

A much more complete and detailed picture of the external environmental gamma-ray radiation field has been obtained through gamma-ray transport calculations of exposure rates, differential energy spectra, integral exposure rate spectra, and angular exposu...

H. Beck G. de Planque

1968-01-01

211

Blindness Due to Sellar Region Tumor Caused Apoplexy; Visual Field Investigation Helps the Diagnosis.  

National Technical Information Service (NTIS)

Chiasmal region tumor caused apoplexy is not uncommon. As its clinical picture varies and is complicated, early diagnosis is usually difficult. 7 cases are reported with marked visual loss, the presenting symptom. Visual fields all revealed definite chias...

L. Yuanxiu

1980-01-01

212

Dynamo effect and current drive due to magnetic fluctuations in sheared magnetic field  

SciTech Connect

It is shown that when the mean electromotive force in a plasma is evaluated in terms of the two-point correlation of driven magnetic field fluctuations (as would be appropriate for problems related to current drive by waves), there is no {beta} effect; i.e., the terms associated with gradients of the mean field vanish. The relevance of this result to the problem of current drive is discussed.

Avinash, K. (Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 78712 (USA))

1991-08-01

213

Computation of induced electric field and temperature elevation in human due to lightning current  

NASA Astrophysics Data System (ADS)

The present study investigated induced electric field and temperature elevation in specific tissues/organs of an anatomically based human body model for the lightning current. The threshold amplitude of the current inducing ventricular fibrillation and skin burning are estimated from computed induced electric field and temperature elevation with formulas for electrical stimulation and thermal damage. The computational results obtained herein were reasonably consistent with clinical observation.

Nagai, T.; Hirata, A.

2010-05-01

214

Wake fields effects due to surface roughness in a circular pipe  

NASA Astrophysics Data System (ADS)

The problem of the wake field generated by a relativistic particle travelling in a long beam pipe with rough surface has been revisited by means of a standard theory based on the hybrid modes excited in a periodically corrugated waveguide with circular cross section. Slow waves synchronous with the particle can be excited in the structure, producing wake fields whose frequency and amplitude depend on the depth of the corrugation. .

Angelici, M.; Frezza, F.; Mostacci, A.; Palumbo, L.

2001-08-01

215

A blood-oxygenation-dependent increase in blood viscosity due to a static magnetic field  

NASA Astrophysics Data System (ADS)

As the magnetic field of widely used MR scanners is one of the strongest magnetic fields to which people are exposed, the biological influence of the static magnetic field of MR scanners is of great concern. One magnetic interaction in biological subjects is the magnetic torque on the magnetic moment induced by biomagnetic substances. The red blood cell is a major biomagnetic substance, and the blood flow may be influenced by the magnetic field. However, the underlying mechanisms have been poorly understood. To examine the mechanisms of the magnetic influence on blood viscosity, we measured the time for blood to fall through a glass capillary inside and outside a 1.5 T MR scanner. Our in vitro results showed that the blood viscosity significantly increased in a 1.5 T MR scanner, and also clarified the mechanism of the interaction between red blood cells and the external magnetic field. Notably, the blood viscosity increased depending on blood oxygenation and the shear rate of the blood flow. Thus, our findings suggest that even a 1.5 T magnetic field may modulate blood flow.

Yamamoto, Toru; Nagayama, Yuki; Tamura, Mamoru

2004-07-01

216

Theoretical and experimental comparisons of nearfield electrogalvanic fields due to nonlinear polarization layers  

NASA Astrophysics Data System (ADS)

Based on completed experimental electric-field scans and the corresponding finite-element field predictions, it appears that the finite-element numerical technique presents a strong analytical tool in calculating the nearfield (within 650 micrometers electric-field distributions about active microcells. This was analytically achieved with the new double membrane finite-element configuration representing nonlinear polarization and by using a local tangent slope (impedance) definition dependent on the local potential difference. The experimental determination of the normal current was realized with a newly developed scanning vibrating electrode technique. The finite-element model utilizes a priori measured uncoupled polarization curves for pure iron and pure copper. The current densities and the electric field intensity was calculated for all the grid points within the electrolyte and on its boundaries. Results appear to indicate that first order anodic mass loss can be predicted using finite-element predicted current density distributions on the anodic surface and the imposition of Faraday's law. The electric-field correlation established for the normal current-density vector provides the confidence to proceed in the evaluation of electric fields associated with pitting and crevice corrosion.

Kasper, R. G.

1985-02-01

217

Tactile suppression of displacement.  

PubMed

In vision, the discovery of the phenomenon of saccadic suppression of displacement has made important contributions to the understanding of the stable world problem. Here, we report a similar phenomenon in the tactile modality. When scanning a single Braille dot with two fingers of the same hand, participants were asked to decide whether the dot was stationary or whether it was displaced from one location to another. The stimulus was produced by refreshable Braille devices that have dots that can be swiftly raised and recessed. In some conditions, the dot was stationary. In others, a displacement was created by monitoring the participant's finger position and by switching the dot activation when it was not touched by either finger. The dot displacement was of either 2.5 mm or 5 mm. We found that in certain cases, displaced dots were felt to be stationary. If the displacement was orthogonal to the finger movements, tactile suppression occurred effectively when it was of 2.5 mm, but when the displacement was of 5 mm, the participants easily detected it. If the displacement was medial-lateral, the suppression effect occurred as well, but less often when the apparent movement of the dot opposed the movement of the finger. In such cases, the stimulus appeared sooner than when the brain could predict it from finger movement, supporting a predictive rather than a postdictive differential processing hypothesis. PMID:20842353

Ziat, Mounia; Hayward, Vincent; Chapman, C Elaine; Ernst, Marc O; Lenay, Charles

2010-09-15

218

The displaced aggression questionnaire.  

PubMed

Previous measures of aggressive personality have focused on direct aggression (i.e., retaliation toward the provoking agent). An original self-report measure of trait displaced aggression is presented. Exploratory and confirmatory factor analyses provided support for a 3-factor conceptualization of the construct. These analyses identified an affective dimension (angry rumination), a cognitive dimension (revenge planning), and a behavioral dimension (general tendency to engage in displaced aggression). The trait measure demonstrated good internal consistency and test-retest reliability as well as convergent and discriminant construct validity. Unlike other related personality measures, trait displaced aggression significantly predicted indirect indicators of real-world displaced aggression (i.e., self-reported domestic abuse and road rage) as well as laboratory displaced aggression in 2 experiments. PMID:16784350

Denson, Thomas F; Pedersen, William C; Miller, Norman

2006-06-01

219

Three-dimensional myocardial strain analysis based on short- and long-axis magnetic resonance tagged images using a 1D displacement field  

Microsoft Academic Search

A robust algorithm to estimate three-dimensional strain in the left-ventricular heart wall, based on magnetic resonance (MR) grid-tagging in two sets of orthogonal image planes, is presented. Starting-point of this study was to minimize global interpolation and smoothing. Only the longitudinal displacement was interpolated between long-axis images. Homogeneous strain analysis was performed using small tetrahedrons. The method was tested using

Joost P. A Kuijer; J. Tim Marcus; Marco J. W Götte; Albert C van Rossum; Robert M Heethaar

2000-01-01

220

Infrared near-field detection of a narrow resonance due to molecular vibrations in a nanoparticle  

SciTech Connect

Di-iron nonacarbonyl particles on a gold surface have been imaged using an apertureless near-field scanning infrared microscopy. First and second harmonic detection, with and without an auto-homodyning option, have been used to collect the near-field spectrum of a single vibrational mode of the bridging carbonyls in di-iron nonacarbonyl nanocrystalline flakes on a gold surface. The experimental results have been compared to two theoretical models, a static image-dipole effective medium and an image dipole modified by a Fresnel coefficient for the appropriate observation angle. The calculations have taken into account the roughness of the gold film. The phase dependence of the near-field contrast has been investigated using broadband and tunable CO2 lasers. Particle size effects on contrast and spatial resolution have been studied to determine the limits of applicability of the half-space approximation.

Romanov, Vyacheslav; Walker, G.C. (University of Toronto, Toronto, Ontario, Canada)

2007-02-27

221

Neoclassical Drift of Circulating Orbits Due toToroidal Electric Field in Tokamaks  

SciTech Connect

In tokamaks, Ware pinch is a well known neoclassical effect for trapped particles in response to a toroidal electric field. It is generally believed that there exists no similar neoclassical effect for circulating particles without collisions. However, this belief is erroneous, and misses an important effect. We show both analytically and numerically that under the influence of a toroidal electric field parallel to the current, the circulating orbits drift outward toward the outer wall with a characteristic velocity O ({var_epsilon}{sup -1}) larger than the E x B velocity, where {var_epsilon} is the inverse aspect-ratio of a tokamak. During a RF overdrive, the toroidal electric field is anti-parallel to the current. As a consequence, all charged particles, including backward runaway electrons, will drift inward towards the inner wall.

Hong, Qin, Xiaoyin Guan and Nathaniel J. Fisch

2011-07-19

222

A platform to study magnetic field amplification of laser driven shocks due to induced turbulence  

NASA Astrophysics Data System (ADS)

Misaligned pressure and temperature gradients associated with asymmetrical shock waves generate currents which seed magnetic fields (Biermann battery process). These fields could then be further amplified by increasing particle gyration driven by vorticity and turbulence. Studies of such phenomena have been conducted at the Rutherford Appleton Laboratory and scaled to astrophysical conditions (e.g., protogalacitc structure formation) using magnetohydrodynamic scaling techniques. Shock waves were driven in a 1 mbar Argon gas filled chamber from ablation of 500 micron Carbon rods using 300 J of 527 nm, 1 ns pulse light. A plastic grid was positioned 1 cm from the target to drive turbulence with outer scale ˜1 mm (the size of the grid opening). An induction coil, located 2 cm from the grid, was used to measure the magnetic field while optical diagnostics were used to track the fluid flow. Preliminary results and comparisons with hydrodynamic codes will be shown.

Meinecke, Jena; Doyle, Hugo; Bell, A. R.; Crowston, Robert; Drake, Paul; Fatenejad, M.; Hartley, Nick; Koenig, Michel; Kuramitsu, Y.; Kuranz, Carolyn; Lamb, Don; MacDonald, Mike; Miniati, F.; Murphy, Chris; Pelka, Alex; Ravasio, Alessandra; Reville, Brian; Sakawa, Y.; Schekochihin, A. A.; Scopatz, Anthony; Tzeferacos, Petros; Wan, Wesley; Woolsey, Nigel; Gregori, Gianluca

2012-10-01

223

Is there a statistics transmutation due to interaction with Chern-Simons field.  

National Technical Information Service (NTIS)

The classical mechanics of a scalar particle interacting with a Chern-Simons field in the (2+1)-dimensional space-time has been considered. The geometric quantization of this system does not lead to particle statistics transmutation. 6 refs. (Atomindex ci...

G. G. Nanobashvili G. P. Pron'ko

1989-01-01

224

Variations of Mars Gravitational Field and Rotation Due to Seasonal CO 2 Exchange  

Microsoft Academic Search

About a quarter of the Martian atmospheric mass is exchanged between the atmosphere and the polar caps in the course of a Martian year: CO2 condenses to form (or add to) the polar caps in winter and sublimes into the atmosphere in summer. This paper studies the effect of this CO2 mass redistribution on Martian rotation and gravitational field. Two

B. Fong Chao; David Parry Rubincam

1990-01-01

225

Energy conversion of the flare due to direct electric fields from the sheared reconnection  

NASA Astrophysics Data System (ADS)

In this paper we present a new mechanism of the main energy conversion of the solar flare. Since a flare inducing prominence (flux tube) rises Vz ? 300 km s-1, the plasmas below it cannot continuously eject with Alfvén speeds of VA = 3000 km s-1 but probably with Vz ? ±100 km s-1. Plasma up and downflows with VA will within a short duration be blocked between the chromosphere where reconnected flux tubes are piling up, and the slowly rising flux rope. Hence the Petschek slow shock mechanism is difficult to be realized as a major energy converting mechanism. Adopting a conventional reconnecting morphology, we assume a magnetic component parallel to the photospheric neutral line, i.e. sheared fields of By ? 0. Then Gauss’s law leads to non-vanishing electric charges ?; 4?? = -div(V × B/c) ? By?Vz/c?x where the horizontal inflow velocity Vx changes to vertical down-flow Vz (e.g. By ? Bz = 40G and ?x ? 104 km). Then the electric field parallel to the magnetic fields E? calculated from Coulomb’s law from this ? is found to be far greater than the Dreicer field, and accelerates electrons and protons. Thus the horizontally inflowing Poynting energy flux in area Sx is immediately converted to the kinetic energy of electron beams along the magnetic field in area Sz; BVxSx/4?=12menVbeam3Sz with Sx/Sz ? 4. The particle beam energy flux cannot exceed the Poynting energy flux however large E? may be. The total energy can be supplied by 10 keV electrons and nbeam = 2 × 107 cm-3 for Vx = 40 km s-1. This inflow velocity Vx, though restricted by the rising prominence speed, explains the short flare duration consistent to observations. The electron beam flux nbeamVbeam will be simultaneously and co-spatially compensated by the slowly back-flowing bulk electrons, avoiding possible enormous charge pile-up. Instead of the conventional diffusion region, which contains serious difficulties if there is the shear as one should normally expect, we propose a reconnecting small region in the potential magnetic fields. The latter may be created by unwinding motions to erase the shear and to minimize energy, and the time scale is given only from the outside condition free from any diffusive processes such as the anomalous resistivity, because no electric currents may exist.

Hirayama, T.

226

Stability of Miscible Displacements Across Stratified Porous Media  

SciTech Connect

This report studied macro-scale heterogeneity effects. Reflecting on their importance, current simulation practices of flow and displacement in porous media were invariably based on heterogeneous permeability fields. Here, it was focused on a specific aspect of such problems, namely the stability of miscible displacements in stratified porous media, where the displacement is perpendicular to the direction of stratification.

Shariati, Maryam; Yortsos, Yanis C.

2000-09-11

227

The use of SPAMM to assess spatial distortion due to static field inhomogeneity in dental MRI.  

PubMed

In planning placement of dental implants using MRI, a SPAMM (spatial modulation of magnetization) magnetization preparation sequence was incorporated into a spin-echo imaging sequence. A phantom was imaged with a ferromagnetic object attached. Spatial distortion due to deviations in Larmor frequency was detected by a deviation of SPAMM lines. Both SPAMM line deviation and interline spacing were found to agree with a deltaB0 map generated from phase images. Imaging of a volunteer with and without typically used metallic implants positioned in a template showed SPAMM line deviations to correlate with expected deviations in vivo. SPAMM lines showed possible distortion due to chemical shift in the bone marrow and the presence of titanium implants to be insignificant. SPAMM may thus be used to provide a qualitative estimate of the accuracy of the MRI image when planning dental implants. PMID:11384057

Bridcut, R R; Redpath, T W; Gray, C F; Staff, R T

2001-05-01

228

Gravity Field Changes due to Long-Term Sea Level Changes  

Microsoft Academic Search

Long-term sea level changes caused by climatic changes (e.g. global warming) will alter the system Earth. This includes the redistribution of ocean water masses due to the migration of cold fresh water from formerly ice-covered regions to the open oceans mainly caused by the deglaciation of polar ice caps. Consequently also a change in global ocean circulation patterns will occur.

O. Makarynskyy; M. Kuhn; W. E. Featherstone

2004-01-01

229

Giant Spin-Orbit Interaction Due to Rotating Magnetic Fields in Graphene Nanoribbons  

NASA Astrophysics Data System (ADS)

We study graphene nanoribbons theoretically in the presence of spatially varying magnetic fields produced, e.g., by nanomagnets. We show, both analytically and numerically, that an exceptionally large Rashba spin-orbit interaction of the order of 10 meV can be produced by a nonuniform magnetic field. As a consequence, helical modes exist in armchair nanoribbons that exhibit nearly perfect spin polarization and are robust against boundary defects. This result paves the way for realizing spin-filter devices in graphene nanoribbons in the temperature regime of a few kelvins. If a nanoribbon in the helical regime is in proximity contact to an s-wave superconductor, the nanoribbon can be tuned into a topological phase that sustains Majorana fermions.

Klinovaja, Jelena; Loss, Daniel

2013-01-01

230

Antiproton cross-field diffusion in antihydrogen production experiments due to anisotropic binary interactions  

NASA Astrophysics Data System (ADS)

Collisional processes in electrostatic ion storage rings and reflecting-beam-type electrostatic ion traps can be associated with anisotropic binary interactions, because shielding of the Coulomb interactions may not take place in one or more dimensions. Collisional scattering theory has recently been developed for describing the velocity space scattering processes in such systems [J.R. Correa, Y. Chang, C.A. Ordonez, Phys. Plasmas 12 (2005) 084505]. The theory is extended to enable the effect of a magnetic field to be included. The theory is intended to be applicable, for example, to antiproton scattering within nested Penning traps that are used to produce antihydrogen [M. Amoretti et al., Nature 419 (2002) 456; G. Gabrielse et al., Phys. Rev. Lett. 89 (2002) 213401]. The theory is applied for considering the cross-magnetic-field diffusion of the antiprotons.

Ordonez, C. A.; Correa, J. R.

2007-08-01

231

Enhanced photorefractive beam fanning due to internal and external electric fields.  

PubMed

Significant increases (x10) in both speed and gain of the beam fanning process were obtained via three different methods in SBN and BSKNN. These methods involve the creation of a dc electric field either (1) externally, (2) by the pyroelectric effect, or (3) by thermally cycling the crystal and the presence of laser radiation. The enhanced effects were observed for both ordinary and extraordinary polarized light. PMID:20562988

Clark Iii, W W; Wood, G L; Miller, M J; Sharp, E J; Salamo, G J; Monson, B; Neurgaonkar, R R

1990-03-20

232

Suppression of small baryonic structures due to a primordial magnetic field  

NASA Astrophysics Data System (ADS)

We investigate the impact of the existence of a primordial magnetic field on the filter mass, characterizing the minimum baryonic mass that can form in dark matter (DM) haloes. For masses below the filter mass, the baryon content of DM haloes are severely depressed. The filter mass is the mass when the baryon to DM mass ratio in a halo is equal to half the baryon to DM ratio of the Universe. The filter mass has previously been used in semi-analytic calculations of galaxy formation, without taking into account the possible existence of a primordial magnetic field. We examine here its effect on the filter mass. For homogeneous comoving primordial magnetic fields of B0 ~ 1 or 2nG and a re-ionization epoch that starts at a redshift zs = 11 and is completed at zr = 8, the filter mass is increased at redshift 8, for example, by factors of 4.1 and 19.8, respectively. The dependence of the filter mass on the parameters describing the re-ionization epoch is investigated. Our results are particularly important for the formation of low-mass galaxies in the presence of a homogeneous primordial magnetic field. For example, for B0 ~ 1nG and a re-ionization epoch of zs ~ 11 and zr ~ 7, our results indicate that galaxies of total mass M ~ 5 × 108Msolar need to form at redshifts zF >~ 2.0, and galaxies of total mass M ~ 108Msolar at redshifts zF >~ 7.7.

Rodrigues, Luiz Felippe S.; de Souza, Rafael S.; Opher, Reuven

2010-07-01

233

Melt Motion Due to Peltier Marking during Bridgman Crystal Growth with an Axial Magnetic Field  

Microsoft Academic Search

This paper treats a liquid-metal flow inside an electrically insulating cylinder with electrically conducting solids above\\u000a and below the liquid region. There is a uniform axial magnetic field, and there is an electric current through the liquid\\u000a and both solids. Since the lower liquid-solid interface is concave into the solid and since the liquid is a better electrical\\u000a conductor than

C. C. Sellers; J. S. Walker; F. R. Szofran; S. Motakef

2000-01-01

234

Inputs of heavy metals due to agrochemical use in tobacco fields in Brazil's Southern Region.  

PubMed

Only a few studies have assessed the joint incorporation of heavy metals into agricultural systems based on the range of agrochemicals used on a specific agricultural crop. This study was conducted to assess the heavy metals input through application of the main agrochemicals used in Brazilian tobacco fields. A total of 56 samples of different batches of 5 fertilizers, 3 substrates, 8 insecticides, 3 fungicides, 2 herbicides, and 1 growth regulator commonly used in the cultivation of tobacco in Brazil's Southern Region were collected from 3 warehouses located in the States of Rio Grande do Sul, Santa Catarina, and Paraná. The total As, Cd, Co, Cr, Cu, Hg, Fe, Mn, Ni, Pb, and Zn content of the samples was then determined and compared with the regulations of different countries and information found in the available literature. The fertilizers were identified as the primary source of heavy metals among the agrochemicals used. Application of pesticides directly to the shoots of tobacco plants contributed very little to the supply of heavy metals. The agrochemicals used in Brazilian tobacco fields provide lower inputs of the main heavy metals that are nonessential for plants than those registered in the international literature for the majority of crop fields in different regions of the world. PMID:22729828

Zoffoli, Hugo José Oliveira; do Amaral-Sobrinho, Nelson Moura Brasil; Zonta, Everaldo; Luisi, Marcus Vinícius; Marcon, Gracioso; Tolón-Becerra, Alfredo

2012-06-23

235

Undulation instability in a bilayer lipid membrane due to electric field interaction with lipid dipoles  

NASA Astrophysics Data System (ADS)

Bilayer lipid membranes (BLMs) are an essential component of all biological systems, forming a functional barrier for cells and organelles from the surrounding environment. The lipid molecules that form membranes contain both permanent and induced dipoles, and an electric field can induce the formation of pores when the transverse field is sufficiently strong (electroporation). Here, a phenomenological free energy is constructed to model the response of a BLM to a transverse static electric field. The model contains a continuum description of the membrane dipoles and a coupling between the headgroup dipoles and the membrane tilt. The membrane is found to become unstable through buckling modes, which are weakly coupled to thickness fluctuations in the membrane. The thickness fluctuations, along with the increase in interfacial area produced by membrane buckling, increase the probability of localized membrane breakdown, which may lead to pore formation. The instability is found to depend strongly on the strength of the coupling between the dipolar headgroups and the membrane tilt as well as the degree of dipolar ordering in the membrane.

Bingham, Richard J.; Olmsted, Peter D.; Smye, Stephen W.

2010-05-01

236

Probing the mechanical properties of seismically active crust with space geodesy: Study of the coseismic deformation due to the 1992 Mw7.3 Landers (southern California) earthquake  

Microsoft Academic Search

The coseismic deformation due to the 1992 Mw7.3 Landers earthquake, southern California, is investigated using synthetic aperture radar (SAR) and Global Positioning System (GPS) measurements. The ERS-1 satellite data from the ascending and descending orbits are used to generate contiguous maps of three orthogonal components (east, north, up) of the coseismic surface displacement field. The coseismic displacement field exhibits symmetries

Yuri Fialko

2004-01-01

237

In-plane and out-of-plane displacement measurement in a wide dynamic range with a modified ESPI system  

NASA Astrophysics Data System (ADS)

Presented is the possibility of full-field displacement measurement in a wide dynamic range, using the hardware and software of a standard ESPI system. In-plane displacement measurements are performed by double symmetrical ullumination of the object, successively for each illumination direction, at a step-wise increase of the loading. The final result is the sum of the individual displacments for each loading step, thus overcoming the constraints due to decorrelation of the interference patterns, and ensuring high accuracy in a wide dynamic range. The out-of-plane displacements are measured by the method of interference fringe projection. The phase-stepping technique with digital processing of interference patterns provides high accuracy in a wide dynamic range, as well as real-time observation of displacements, typical for TV ESPI systems. Presented are experimental results; the prospoects for additional noise filtering are pointed out.

Boone, Pierre M.; Sainov, Ventzeslav C.; van der Linden, Johan E.

1995-06-01

238

Comments on "Evaluation of interactions of electric fields due to electrostatic discharge with human tissue".  

PubMed

Attention is drawn to recent paper by Rogers et al. (Aug., 2004) in which ultra-wideband pulses are applied to an isolated muscle as part of deriving a strength-duration curve for threshold stimulation. The paper extends the strength-duration threshold curve for unipolar pulses down to a pulse duration of about 1 ns, on the order of 1000 times shorter than previously studied. Results of the work justify use of traditional mathematical models of the strength-duration curve for nanosecond pulses, as done recently for the electric field resulting from electrostatic discharge through the body (Dawson, et al., 2004). PMID:16761853

Seaman, Ronald L; Comeaux, James A

2006-06-01

239

Variance and covariance of accumulated displacement estimates.  

PubMed

Tracking large deformations in tissue using ultrasound can enable the reconstruction of nonlinear elastic parameters, but poses a challenge to displacement estimation algorithms. Such large deformations have to be broken up into steps, each of which contributes an estimation error to the final accumulated displacement map. The work reported here measured the error variance for single-step and accumulated displacement estimates using one-dimensional numerical simulations of ultrasound echo signals, subjected to tissue strain and electronic noise. The covariance between accumulation steps was also computed. These simulations show that errors due to electronic noise are negatively correlated between steps, and therefore accumulate slowly, whereas errors due to tissue deformation are positively correlated and accumulate quickly. For reasonably low electronic noise levels, the error variance in the accumulated displacement estimates is remarkably constant as a function of step size, but increases with the length of the tracking kernel. PMID:23493610

Bayer, Matthew; Hall, Timothy J

2013-04-01

240

Kinematics Problem: Displacement  

NSDL National Science Digital Library

A bowling ball is lifted from rest onto a shelf by an external agent (position is in meters and time is in seconds). Rank the paths by the displacement of the bowling ball during the animations (greatest first).

Christian, Wolfgang; Belloni, Mario

2006-01-20

241

Precision Displacement Mechanism (PDM).  

National Technical Information Service (NTIS)

A mechanism designed to fulfill the requirements of the Precision Displacement Mechanism (PDM) for the Far Infrared and Submillimeter Space Telescope (FIRST) antenna is described. The PDM function is to perform the fine adjustment of the position of the m...

J. I. Bueno F. Delcampo P. Coste

1993-01-01

242

Global simulation of proton precipitation due to field line curvature during substorms  

NASA Astrophysics Data System (ADS)

The low latitude boundary of the proton aurora (known as the Isotropy Boundary or IB) marks an important boundary between empty and full downgoing loss cones. There is significant evidence that the IB maps to a region in the magnetosphere where the ion gyroradius becomes comparable to the local field line curvature. However, the location of the IB in the magnetosphere remains in question. In this paper, we show simulated proton precipitation derived from the Field Line Curvature (FLC) model of proton scattering and a global magnetohydrodynamic simulation during two substorms. The simulated proton precipitation drifts equatorward during the growth phase, intensifies at onset and reproduces the azimuthal splitting published in previous studies. In the simulation, the pre-onset IB maps to 7-8 RE for the substorms presented and the azimuthal splitting is caused by the development of the substorm current wedge. The simulation also demonstrates that the central plasma sheet temperature can significantly influence when and where the azimuthal splitting takes place.

Gilson, M. L.; Raeder, J.; Donovan, E.; Ge, Y. S.; Kepko, L.

2012-05-01

243

Excessive magnetic field flux density distribution from overhead isolated powerline conductors due to neutral line current.  

PubMed

Overhead isolated powerline conductors (hereinafter: "OIPLC") are the most compact form for distributing low voltage currents. From the known physics of magnetic field emission from 3-phase power lines, it is expected that excellent symmetry of the 120° shifted phase currents and where compact configuration of the 3-phase+neutral line exist, the phase current vectorial summation of the magnetic field flux density (MFFD) is expected to be extremely low. However, despite this estimation, an unexpectedly very high MFFD was found in at least three towns in Israel. This paper explains the reasons leading to high MFFD emissions from compact OIPLC and the proper technique to fix it. Analysis and measurement results had led to the failure hypothsis of neutral line poor connection design and poor grounding design of the HV-LV utility transformers. The paper elaborates on the low MFFD exposure level setup by the Israeli Environmental Protection Office which adopted a rather conservative precaution principal exposure level (2 mG averaged over 24 h). PMID:23675630

Netzer, Moshe

2013-06-01

244

SOI detector with drift field due to majority carrier flow - an alternative to biasing in depletion  

SciTech Connect

This paper reports on a SOI detector with drift field induced by the flow of majority carriers. It is proposed as an alternative method of detector biasing compared to standard depletion. N-drift rings in n-substrate are used at the front side of the detector to provide charge collecting field in depth as well as to improve the lateral charge collection. The concept was verified on a 2.5 x 2.5 mm{sup 2} large detector array with 20 {micro}m and 40 {micro}m pixel pitch fabricated in August 2009 using the OKI semiconductor process. First results, obtained with a radioactive source to demonstrate spatial resolution and spectroscopic performance of the detector for the two different pixel sizes will be shown and compared to results obtained with a standard depletion scheme. Two different diode designs, one using a standard p-implantation and one surrounded by an additional BPW implant will be compared as well.

Trimpl, M.; Deptuch, G.; Yarema, R.; /Fermilab

2010-11-01

245

Mode field perturbations and numerical aperture broadening due to angular misalignment in multimode fiber coupling  

NASA Astrophysics Data System (ADS)

Large core multimode fibers (MMF) in the range of 100-1000 ?m core diameter are commonly used with infrared lasers in medical, bio-photonics and other fiber optics applications. Angular misalignment of the laser source to the multimode fiber can lead to unusual angular patterns at the exit of the fiber. The angular content of the launch beam can result in under-filling, non-uniform angular filling, or over-filling of the MMF modes. Typically, the beam condition optics at the distal end of the device has a limited impact on these angular modes. The result is often loss of output power at the distal end or an uncontrolled angular and/or spatial distribution of light. We have investigated angular misalignment perturbations of various fiber and coupling optics combinations in a medical laser therapy device. We have quantified the resulting far field perturbations, as well as the resulting broadening of the fiber output numerical aperture (NA). Angular misalignment may cause the development of so called "donut modes" with highly inhomogeneous far field mode distribution, as well as a substantial NA broadening effect which may impact therapy. We have shown that in order to avoid these perturbations, tight tolerancing of fiber coupling opto-mechanics as well as a thorough alignment procedure is required.

Rose, Andreas; Johnston, Kyle; Klein, Karl-Friedrich; Catanzaro, Brian; de Taboada, Luis

2009-02-01

246

Variations of Mars gravitational field and rotation due to seasonal CO sub 2 exchange  

SciTech Connect

About a quarter of the Martian atmospheric mass is exchanged between the atmosphere and the polar caps in the course of a Martian year: CO{sub 2} condenses to form (or add to) the polar caps in winter and sublimes into the atmosphere in summer. This paper studies the effect of this CO{sub 2} mass redistribution on Martian rotation and gravitational field. Two mechanisms are examined: (1) the waxing and waning of solid CO{sub 2} in the polar caps and (2) the geographical distribution of gaseous CO{sub 2} in the atmosphere. In particular, the net peak-to-peak changes in J{sub 2} and J{sub 3} over a Martian year are both found to be as much as {approximately}6 {times} 10{sup {minus}9}. A simulation suggests that these changes may be detected by the upcoming Mars Observer under favorable but realistic conditions.

Chao, B.F.; Rubincam, D.P. (Goddard Space Flight Center, Greenbelt, MD (USA))

1990-08-30

247

Field-induced relaxation of bulk composition due to internal boundaries  

NASA Astrophysics Data System (ADS)

The establishment of compositional variations in solids caused by an external electric field usually requires electrodes that block either electronic or ionic charge carriers. Here we present unambiguous experimental and theoretical evidence that the compositional variations can occur even in the case of completely nonblocking electrodes if grain boundaries are present. In addition to the proper grain boundary impedance arc characterized by the dielectric relaxation time, ?, a second arc occurs at much lower frequencies (??). It is shown that this low-frequency response refers to a chemical relaxation (Warburg diffusion) induced by the selectively blocking grain boundary. The effect is the analogue to the chemical relaxation induced by selectively blocking electrodes (cf. Wagner-Hebb polarization).

Jamnik, J.; Guo, X.; Maier, J.

2003-04-01

248

Failure of Electromagnetic Voltage Transformer Due to Sustained OverVoltage on Switching - an Indepth Field Investigation and Analytical Study  

Microsoft Academic Search

An electromagnetic voltage transformer (EMVT) was damaged when the 220KV bus bar was being de-energised by a circuit breaker fitted with grading capacitors across its contacts. This paper describes the field investigations and analyses the phenomenon using the principle of harmonic balance. It is established that the failure occurred due to fero-resonance between CB grading capacitors and non-linear EMVT inductance

R. P. Aggarwal; N. S. Saxena; B. S. Sharma; Satish Kumar; Shalindra Krishan

1981-01-01

249

Measurement of plasma boundary displacement by n = 2 magnetic perturbations using imaging beam emission spectroscopy  

NASA Astrophysics Data System (ADS)

Imaging beam emission spectroscopy has been used to study the displacement of the plasma boundary in ELMing H-mode discharges with a 10 Hz rotating n = 2 external magnetic field perturbation in DIII-D. The rotating magnetic field creates a helical displacement of the beam emission profile of ˜2 cm on the low-field-side (LFS) midplane which rotates with the applied resonant magnetic perturbation. This shift in the beam emission profile is due primarily to a shift in the electron density profile, which is independently measured to be 1.9 cm on the LFS midplane. These boundary displacements exceed calculations for the displacement of the stable and unstable manifolds formed by the interaction of the magnetic perturbation with the divertor separatrix by a factor of 4-5, suggesting that the vacuum field model does not correctly model the effect of the magnetic perturbations even near the separatrix. The measured displacements are suggestive of a non-resonant kink response.

Moyer, R. A.; Van Zeeland, M. A.; Orlov, D. M.; Wingen, A.; Evans, T. E.; Ferraro, N. M.; Hanson, J. M.; Nazikian, R.; Wade, M. R.; Zeng, L.

2012-12-01

250

Subsecond spin relaxation times in quantum dots at zero applied magnetic field due to a strong electron-nuclear interaction.  

PubMed

A key to ultralong electron spin memory in quantum dots (QDs) at zero magnetic field is the polarization of the nuclei, such that the electron spin is stabilized along the average nuclear magnetic field. We demonstrate that spin-polarized electrons in n-doped (In,Ga)As/GaAs QDs align the nuclear field via the hyperfine interaction. A feedback onto the electrons occurs, leading to stabilization of their polarization due to formation of a nuclear spin polaron [I. A. Merkulov, Phys. Solid State 40, 930 (1998)]. Spin depolarization of both systems is consequently greatly reduced, and spin memory of the coupled electron-nuclear spin system is retained over 0.3 sec at temperature of 2 K. PMID:17358564

Oulton, R; Greilich, A; Verbin, S Yu; Cherbunin, R V; Auer, T; Yakovlev, D R; Bayer, M; Merkulov, I A; Stavarache, V; Reuter, D; Wieck, A D

2007-03-07

251

Subsecond Spin Relaxation Times in Quantum Dots at Zero Applied Magnetic Field Due to a Strong Electron-Nuclear Interaction  

NASA Astrophysics Data System (ADS)

A key to ultralong electron spin memory in quantum dots (QDs) at zero magnetic field is the polarization of the nuclei, such that the electron spin is stabilized along the average nuclear magnetic field. We demonstrate that spin-polarized electrons in n-doped (In,Ga)As/GaAs QDs align the nuclear field via the hyperfine interaction. A feedback onto the electrons occurs, leading to stabilization of their polarization due to formation of a nuclear spin polaron [I. A. Merkulov, Phys. Solid State 40, 930 (1998).PSOSED1063-783410.1134/1.1130450]. Spin depolarization of both systems is consequently greatly reduced, and spin memory of the coupled electron-nuclear spin system is retained over 0.3 sec at temperature of 2 K.

Oulton, R.; Greilich, A.; Verbin, S. Yu.; Cherbunin, R. V.; Auer, T.; Yakovlev, D. R.; Bayer, M.; Merkulov, I. A.; Stavarache, V.; Reuter, D.; Wieck, A. D.

2007-03-01

252

Microstructural changes in a cementitious membrane due to the application of a DC electric field.  

PubMed

The use of electromigration techniques to accelerate chloride ions motion is commonly employed to characterise the permeability of cementitious samples to chlorides, a relevant parameter in reinforced concrete corrosion. This paper is devoted to the study of microstructure's changes occurring in mortar samples when submitted to natural diffusion and migration experiments. The application of an electric field reduces testing time in about one order of magnitude with respect to natural diffusion experiments. Nevertheless, the final sample's microstructure differs in both tests. Impedance Spectroscopy is employed for real time monitoring of microstructural changes. During migration experiments the global impedance undergoes important increase in shorter period of time compared to natural diffusion tests. So, the forced motion of ions through the concrete membrane induces significant variations in the porous structure, as confirmed by Mercury Intrusion Porosimetry. After migration experiments, an important increase in the capillary pore size (10-100 nm) was detected. Conversely, no relevant variations are found after natural diffusion tests. Results presented in this work cast doubt on the significance of diffusion coefficient values obtained under accelerated conditions. PMID:18569312

Covelo, Alba; Diaz, Belen; Freire, Lorena; Novoa, X Ramon; Perez, M Consuelo

2008-07-01

253

Exploration of Quench Initiation Due to Intentional Geometrical Defects in a High Magnetic Field Region of an SRF Cavity  

SciTech Connect

A computer program which was used to simulate and analyze the thermal behaviors of SRF cavities has been developed at Jefferson Lab using C++ code. This code was also used to verify the quench initiation due to geometrical defects in high magnetic field region of SRF cavities. We built a CEBAF single cell cavity with 4 artificial defects near equator, and this cavity has been tested with T-mapping. The preheating behavior and quench initiation analysis of this cavity will be presented here using the computer program.

J. Dai, K. Zhao, G.V. Eremeev, R.L. Geng, A.D. Palczewski

2011-07-01

254

Fragmentation due to centrifugal forces in the photodissociation of H{sub 2}{sup +} in intense laser fields  

SciTech Connect

By means of quantum-dynamical and classical trajectory calculations of H{sub 2}{sup +} photodissociation in strong laser fields, it is shown that for certain combinations of pulse durations and intensities the rotational dynamics can lead to fragmentation. In that case, the photofragments exhibit characteristic angular distributions. The classical calculations provide a transparent physical picture of this mechanism which is also very well established in collisions between atomic nuclei or liquid droplets: nonrotating systems are stable, whereas rotating systems fragment due to the decrease of the fragmentation barrier with increasing angular momentum.

Fischer, Michael; Schmidt, Ruediger [Institut fuer Theoretische Physik, Technische Universitaet Dresden, Zellescher Weg 17, D-01069 Dresden (Germany); Lorenz, Ulf [HASYLAB at DESY, Notkestr. 85, D-22607 Hamburg (Germany); Schmidt, Burkhard [Institut fuer Mathematik, Freie Universitaet Berlin, Arnimallee 6, D-14195 Berlin (Germany)

2011-09-15

255

A Study of Transient Magnetic Fields in a Nacelle of a Wind Turbine Generator System due to Lightning  

NASA Astrophysics Data System (ADS)

A wind turbine generator system is composed of blades, a nacelle, a tower etc. In recent year, to make the blades and the nacelle lighter, the blades are often made from GFRP (Glass Fiber Reinforced Plastics) and the nacelle is composed of steel grids and GFRP covering it. When the lightning strikes the wind turbine, the current flows into the ground through the down conductor in the blades, the steel grids of nacelle, and the tower. The current flowing near the nacelle produces comparatively large magnetic fields inside the nacelle. Therefore, the communication and control systems are broken down or malfunction. In this paper, the transient magnetic fields in a nacelle due to lightning strokes at the tip of the blade and the rear portion of the nacelle are studied analytically and experimentally. In the analytical studies, the FDTD (Finite Difference Time Domain) method which is one of numerical electromagnetic field analyses is used. The reduced-size model of a wind turbine is used for experimental studies. As the results of the researches, it has been found that the magnetic fields at the front of the nacelle are larger than those at the rear of the nacelle regardless of the injected points of the lightning current. The lightning current following through the down conductor connected to the nacelle through the blades has a strong influence on the magnetic fields in the nacelle. We have proposed that the front of the nacelle should be covered with the conductor plate or mesh to decrease the large magnetic fields.

Yamamoto, Kazuo; Chikara, Tomohiro; Ametani, Akihiro

256

Orientation-dependent phenomena in photoelectron angular distributions due to strong-field ionization of laser-irradiated diatomic molecules  

NASA Astrophysics Data System (ADS)

We report about orientation-dependent effects arising in molecular photoelectron angular distributions (PAD) due to well pronounced contribution from ionization of inner molecular valence shell(s) to strong-field above-threshold ionization of laser-irradiated homonuclear diatomic molecules (N2, O2 and F2). In particular, our calculation results, obtained within the Density-Functional-Theory based Strong-Field-Approximation [V. I. Usachenko, P. E. Pyak and V. V. Kim Phys. Rev. A 79 116901 (2009)], suggest that within the high-intensity field domain (I >=3.10^14 W/cm^2) the molecular ionization dynamics for internuclear axis orientation angles ?/3 <=?<=2?/3 (with respect to the incident laser field polarization) does become very pronounced and manifested by the well predominant contribution rather from the 1?u inner shell than from the highest occupied molecular orbital (HOMO) (3?g in N2 or 1?g in O2 and F2, normally predominantly contributing under standard cases).

Usachenko, Vladimir; Pyak, Pavel; Kim, Vyacheslav; Chu, Shih-I.

2009-05-01

257

Displacement sensors using soft magnetostrictive alloys  

SciTech Connect

The authors report results on the response of a family of displacement sensors, which are based on the magnetostrictive delay line (MDL) technique, using current conductor orthogonal to the MDL. Such sensing technique is based on the change of the magnetic circuit and the acoustic stress point of origin due to the displacement of a soft magnetic material above it. Integrated arrays of sensors can be obtained due to the acoustic delay line technique and they can be used as tactile arrays, digitizers or devices for medical application (gait analysis etc.), while absence of hysteresis and low cost of manufacturing make them competent in this sector of sensor market.

Hristoforou, E. (NCSR Demokritos Aghia Paraskevi, Athens (Greece). Inst. of Material Science); Reilly, R.E. (King's College London (United Kingdom). Electronic and Electrical Engineering Dept.)

1994-09-01

258

Global displacement models 1  

Microsoft Academic Search

An introduction into global displacement models is presented. The local dynamical equation in the Eulerian and the Lagrangean description is reviewed with reference to stress tensors of type Cauchy, Piola, Kirchhoff and Finger. Constitutive equations for linear viscoelastic material with isotropic prestress are discussed. The role of frame velocity and frame acceleration or of Coriolis acceleration, Euler acceleration (gyroscopic or

E. W. Grafarend

1982-01-01

259

Character displacement in Hydrobia  

Microsoft Academic Search

Fenchel's study of size variation in Hydrobiid snails in the Limfjord, Denmark, provides one of the most convincing cases of ecological character displacement available. In order to assess the generality of the phenomena within the Hydrobia genus, allopatric and sympatric Hydrobia ventrosa, H. neglecta and H. ulvae were collected from 24 coastal sites around Eastern England in July and October,

A. J. Cherrill; R. James

1987-01-01

260

Romanticism displaced and placeless  

Microsoft Academic Search

Displacement, deriving mainly from the circumstances of the first modern world war, is an abiding notion in European Romanticism. It can take the form of a fragmentation of psychic identity through loss of nationality, as we find in Ugo Foscolo, or of the exile’s split between nationalist identities, as exemplified by Germaine de Staël’s Corinne. But in the literature of

Stuart Curran

2009-01-01

261

Liquid CO2 Displacement of Water in a Dual-Permeability Pore Network Micromodel  

SciTech Connect

Permeability contrasts exist in multilayer geological formations under consideration for carbon sequestration. To improve our understanding of heterogeneous pore-scale displacements, liquid CO2 (LCO2) - water displacement was evaluated in a pore network micromodel with two distinct permeability zones. Due to the low viscosity ratio (logM = -1.1), unstable displacement occurred at all injection rates over two orders of magnitude. LCO2 displaced water only in the high permeability zone at low injection rates with the mechanism shifting from capillary fingering to viscous fingering with increasing flow rate. At high injection rates, LCO2 displaced water in the low permeability zone with capillary fingering as the dominant mechanism. LCO2 saturation (SLCO2) as a function of injection rate was quantified using fluorescent microscopy. In all experiments, more than 50% of LCO2 resided in the active flowpaths, and this fraction increased as displacement transitioned from capillary to viscous fingering. A continuum-scale two-phase flow model with independently determined fluid and hydraulic parameters was used to predict SLCO2 in the dual-permeability field. Agreement with the micromodel experiments was obtained for low injection rates. However, the numerical model does not account for the unstable viscous fingering processes observed experimentally at higher rates and hence overestimated SLCO2.

Zhang, Changyong; Oostrom, Martinus; Grate, Jay W.; Wietsma, Thomas W.; Warner, Marvin G.

2011-09-01

262

Output Voltage Characteristics of Eddy Current Displacement Sensor for Various Heat Treatments of Measuring Objects  

Microsoft Academic Search

The output voltage of an eddy current displacement sensor (EC displacement sensor) depends on the heat treatment of the measuring object. The EC displacement sensor must detect a displacement of several tens of mum to allow the examination of the change in output voltage due to the heat treatment of the measuring object. Thus, we measure the relative permeability and

Tsutomu Mizuno; Shigemi Enoki; Takashi Asahina; Takayuki Suzuki; Hiroyuki Maeda; Takafumi Asahi; Hiroki Shinagawa

2008-01-01

263

Stress change due to the 2005 Miyagi-Oki earthquake and stress field of the Miyagi-Oki region  

NASA Astrophysics Data System (ADS)

Interplate earthquakes of M ~ 7.5 have occurred along the subducting plate boundary of the Miyagi-Oki region, middle part of the Japan Trench area, repeatedly at about 40 years intervals. In 2005, an interplate earthquake of M 7.2 occurred in this region and was observed by ocean bottom seismometers deployed in the source region. We attempt to understand the seismogenic mechanism in the Miyagi-Oki region by estimating the stress field from these data and further by comparing the obtained stress field with spatiotemporal variations of interplate slip or of microseismicity. Suzuki et al. (2009) estimated the regional stress field from the focal mechanisms of small earthquakes. They also investigated residuals between slip directions of the observed focal mechanisms and those expected from the obtained stress filed for each of the earthquakes. It turned out that that the earthquakes along the eastern rim of the rupture area of the 2005 mainshock tend to have large residuals. Since most of the earthquakes with large residuals occurred after the mainshock, it is probable that these earthquakes occurred in response to the stress disturbance caused by the mainshock. We calculated ?CFF due to the coseismic slip of the mainshock in order to measure quantitatively how the stress change could affect the seismicity. To calculate ?CFF, we assumed the hypocenter and the focal mechanism determined by Suzuki et al. (2009), and the spatial extent of the source area and the coseismic slip amount estimated by Yaginuma (2006). In the eastern rim of the mainshock, where stress change was supposed to account for the intense aftershock activity, most of the aftershocks have rupture planes on which positive ?CFF values were calculated. This result supports that stress change due to the mainshock rupture affected the aftershock activity. Besides, we estimated three-dimensional variation of the stress fields by dividing the study area into several small subvolumes in which stress-tensors were inverted for by using the method of Gephart and Forsyth (1984). Maximum principal stress axes tend to be vertical in the overriding North American plate, but those in the subducting Pacific plate tend to be parallel to the downgoing direction of the slab. This change in the stress filed across the plate boundary might indicate that the interplate coupling in the Miyagi-Oki region was weak during the aftershock activity of the 2005 earthquake. More in detail, the stress field seems to have regional variation as well as the change across the plate boundary. It is probable that these spatial variations reflect heterogeneity of the frictional property along the plate boundary.

Suzuki, K.; Hino, R.; Ito, Y.; Kanazawa, T.; Yamada, T.; Shinohara, M.; Uehira, K.; Yamamoto, Y.; Kaneda, Y.

2009-12-01

264

Toward development of parameters for permeability field variations due to fluid-rock reactions during geologic CO2 sequestration  

NASA Astrophysics Data System (ADS)

Injection of supercritical carbon dioxide, CO2, into deep saline aquifers and other formations during geologic CO2 sequestration, can result in complex fluid-rock reactions, potentially mitigated by biological processes. Such reactions may result in mineral dissolution or precipitation that in turn can modify fluid flow path geometries and related permeability fields. Changes in permeability affect fluid flow rates and flow patterns, as well as advection of chemical or biological components, with corresponding changes in fluid-rock reactions, thereby closing a complex feedback loop. In this loop, one of the least-well understood components concerns how much and where mineral dissolution or precipitation occurs and how these modifications in flow path geometry affect the permeability field. Here, we introduce a set of experimental and numerical approaches that are designed to quantify the changes in flow path morphology due to mineral dissolution or precipitation upon injection of supercritical CO2 into a range of host rocks or sediments that may be considered for CO2 sequestration. These quantifications will then be used in lattice-Boltzmann simulations of reactive multiphase-multicomponent fluid flow to develop parameters of permeability tensor field variations for continuum models and simulators such as TOUGH2.

Saar, M. O.; Seyfried, W. E.

2010-12-01

265

Study on optical fiber based displacement sensor  

NASA Astrophysics Data System (ADS)

Fiber optic sensor is commonly used in control and monitoring system for material deformation, strain, temperature, pressure and other industrial process parameters. Fiber optic displacement sensor based on intensity modulation can be designed by using the transmission technique where the intensity gradually changes due to change of detected laser intensity. Previous optical fiber based displacement sensors are constructed using two fibers along with a mirror arrangement or a single optical fiber acting as both transmitter and receiver such as 2X1 fiber couplers. The reported resolution of the system was in the range of 5 ?m-10 ?m. In our present study the displacement sensor composed of a laser source, optical fiber cable, microscope objective and power meter is designed. As in source-fiber coupling geometry, the microscope objective focuses the laser light onto a multimode glass fiber. The other end of the fiber is coupled to a power meter. As the fiber is displaced towards the focused spot, the detected power changes. The displacement resolution of 5 ?m is obtained with this simple setup. In the present paper, the results of theoretical analysis and experimental study of such a simple optical fiber based displacement sensor are presented.

Chakraborty, B.; Sinha, B. K.

2011-10-01

266

Displaced patella fractures.  

PubMed

Displaced patella fractures often result in disruption of the extensor mechanism of the knee. An intact extensor mechanism is a requirement for unassisted gait. Therefore, operative treatment of the displaced patella fracture is generally recommended. The evaluation of the patella fracture patient includes examination of extensor mechanism integrity. Operative management of patella fractures normally includes open reduction with internal fixation, although partial patellectomy is occasionally performed, with advancement of quadriceps tendon or patellar ligament to the fracture bed. Open reduction with internal fixation has historically been performed utilizing anterior tension band wiring, although comminution of the fracture occasionally makes this fixation construct inadequate. Supplementation or replacement of the tension band wire construct with interfragmentary screws, cerclage wire or suture, and/or plate-and-screw constructs may add to the stability of the fixation construct. Arthrosis of the patellofemoral joint is very common after healing of patella fractures, and substantial functional deficits may persist long after fracture healing has occurred. PMID:23966286

Della Rocca, Gregory J

2013-08-21

267

The Displaced Aggression Questionnaire  

Microsoft Academic Search

Previous measures of aggressive personality have focused on direct aggression (i.e., retaliation toward the provoking agent). An original self-report measure of trait displaced aggression is presented. Exploratory and confirmatory factor analyses provided support for a 3-factor conceptualization of the construct. These analyses identified an affective dimension (angry rumination), a cognitive dimension (revenge planning), and a behavioral dimension (general tendency to

Thomas F. Denson; William C. Pedersen; Norman Miller

2006-01-01

268

Above Water: Buoyancy & Displacement  

NSDL National Science Digital Library

In an investigation called "Shape It!" learners craft tiny boats out of clay, set them afloat on water and then add weight loads to them, in order to explore: how objects stay afloat in water; what the relationship is among surface tension, buoyancy, density and displacement; and how shape, size, and type of material affect an object's ability to remain buoyant. The introductory text discusses how heavy steel ships can float on bodies of water like rivers, bays and oceans.

Jersey, New; Center, Liberty S.; Coalition, New J.

2006-01-01

269

Investigating the relation between geothermal reservoir compaction, geometry and production rates from a ten-year InSAR ground displacement history at the Bradys and Desert Peak fields: Assessing the potential of retrospective InSAR monitoring to assist reservoir management and expansion over fields without previously documented subsidence  

Microsoft Academic Search

Knowledge of a geothermal reservoir's hydro-thermal-mechanical response to production is critical to sustaining and\\/or expanding its production capacity. We propose investigating the relation between geothermal reservoir compaction (or bulk porosity loss), geometry and production rates by recovering a ten-year InSAR ground displacement history at the Bradys and Desert Peak fields, in west central Nevada. Our objectives are to 1) Demonstrate

Gary Oppliger

270

SOFTWARE ENABLED VARIABLE DISPLACEMENT PUMPS - EXPERIMENTAL STUDIES  

Microsoft Academic Search

The majority of hydraulic systems are controlled using a me- tering valve or the use of variable displacement pumps. Metering valve control is compact and has a high control bandwidth, but it is energy inefficient due to throttling losses. Variable d isplace- ment pumps are far more efficient as the pump only produces the required flow, but comes with the

Michael B. Rannow; Haink C. Tu; Perry Y. Li; Thomas R. Chase

2006-01-01

271

Digital Fiber Optic Displacement Sensors.  

National Technical Information Service (NTIS)

A digital fiber optic displacement sensor using a Mach-Zehnder interferometer was tested. The theoretical sensitivity of digital interferometer displacement sensors, and the dual polarization method are presented. Experimental results show that interferom...

N. Fuerstenau

1987-01-01

272

Numerical modelling of thermal effects in rats due to high-field magnetic resonance imaging (0.5 1 GHz)  

NASA Astrophysics Data System (ADS)

A finite-difference time-domain (FDTD) thermal model has been developed to compute the temperature elevation in the Sprague Dawley rat due to electromagnetic energy deposition in high-field magnetic resonance imaging (MRI). The field strengths examined ranged from 11.75-23.5 T (corresponding to 1H resonances of 0.5-1 GHz) and an N-stub birdcage resonator was used to both transmit radio-frequency energy and receive the MRI signals. With an in-plane resolution of 1.95 mm, the inhomogeneous rat phantom forms a segmented model of 12 different tissue types, each having its electrical and thermal parameters assigned. The steady-state temperature distribution was calculated using a Pennes 'bioheat' approach. The numerical algorithm used to calculate the induced temperature distribution has been successfully validated against analytical solutions in the form of simplified spherical models with electrical and thermal properties of rat muscle. As well as assisting with the design of MRI experiments and apparatus, the numerical procedures developed in this study could help in future research and design of tumour-treating hyperthermia applicators to be used on rats in vivo.

Trakic, Adnan; Crozier, Stuart; Liu, Feng

2004-12-01

273

DISPLACEMENT SPECTRA FOR SEISMIC DESIGN  

Microsoft Academic Search

Displacement-based seismic design and assessment of structures require the reliable definition of displacement spectra for a wide range of periods and damping levels. The displacement spectra derived from acceleration spectra in existing seismic codes do not provide a suitable answer and there are no existing frequency-dependent attenuation relationships derived specifically for this purpose. Using a carefully processed dataset of European

JULIAN J. BOMMER; AMR S. ELNASHAI

1999-01-01

274

SOFTWARE ENABLED VARIABLE DISPLACEMENT PUMPS  

Microsoft Academic Search

Direct pump control of hydraulic systems is more energy efficient than throttle valve based methods to control hydra ulic systems. This requires variable displacement pumps that are responsive and capable of electronic control. Such Electronic Displacement Controlled (EDC) pumps tend to be significantl y larger, heavier and more expensive than fixed displacement c oun- terparts. In addition, achievable control bandwidths

Perry Y. Li; Cassie Y. Li; Thomas R. Chase

275

An ion displacement membrame model.  

PubMed

The usual assumption in treating the diffusion of ions in an electric field has been that the movement of each ion is independent of the movement of the others. The resulting equation for diffusion by a succession of spontaneous jumps has been well stated by Parlin and Eyring. This paper will consider one simple case in which a different assumption is reasonable. Diffusion of monovalent positive ions is considered as a series of jumps from one fixed negative site to another. The sites are assumed to be full (electrical neutrality). Interaction occurs by the displacement of one ion by another. An ion leaves a site if and only if another ion, not necessarily of the same species, attempts to occupy the same site. Flux ratios and net fluxes are given as functions of the electrical potential, concentration ratios, and number of sites encountered in crossing the membrane. Quantitative comparisons with observations of Hodgkin and Keynes are presented. PMID:6048876

Hladky, S B; Harris, J D

1967-09-01

276

A lateral-displacement flume for fish behavior and stranding studies during simulated pulsed flows  

Microsoft Academic Search

In regulated rivers, fluctuating water depths associated with pulsed discharges may strand small fish in side channels and\\u000a pools. Quantitative assessments of stranded fish are difficult in field studies (e.g., due to unknown effects of avian and\\u000a terrestrial vertebrate predators). To assess such lateral displacement and stranding on juvenile stream fishes, we designed,\\u000a constructed, and tested (with three species) a

Sarah A. Cocherell; Stephanie N. Chun; Dennis E. Cocherell; Lisa C. Thompson; A. Peter Klimley; Joseph J. Cech Jr

277

Approximation of Electromechanical Stresses in MLC Capacitors Due to Internally Clamped Strains  

Microsoft Academic Search

Internal stresses are calculated in multilayer capacitors due to applied electric fields via axial displacement compatibility relationships. Closed-form solutions are used to depict approximate levels of stresses in the active and margin regions of multilayer ceramic capacitors (MLCs) due to applied DC voltages. Normal strains and shear strains are superimposed in order to calculate the approximate internal electromechanical stresses. Principal

W. B. Carlson; D. E. McCauley

2006-01-01

278

Gas miscible displacement enhanced oil recovery: Technology status report  

SciTech Connect

Gas miscible displacement enhanced oil recovery research is conducted by the US Department of Energy's Morgantown Energy Technology Center to advance the application of miscible carbon dioxide flooding. This research is an integral part of a multidisciplinary effort to improve the technology for producing additional oil from US resources. This report summarizes the problems of the technology and the 1986 results of the ongoing research that was conducted to solve those problems. Poor reservoir volumetric sweep efficiency is the major problem associated with gas flooding and all miscible displacements. This problem results from the channeling and viscous fingering that occur due to the large differences between viscosity or density of the displacing and displaced fluids (i.e., carbon dioxide and oil, respectively). Simple modeling and core flooding studies indicate that, because of differences in fluid viscosities, breakthrough can occur after only 30% of the total pore volume (PV) of the rock has been injected with gas, while field tests have shown breakthrough occurring much earlier. The differences in fluid densities lead to gravity segregation. The lower density carbon dioxide tends to override the residual fluids in the reservoir. This process would be considerably more efficient if a larger area of the reservoir could be contacted by the gas. Current research has focused on the mobility control, computer simulation, and reservoir heterogeneity studies. Three mobility control methods have been investigated: (1) the use of polymers for direct thickening of high-density carbon dioxide, (2) mobile ''foam-like dispersions'' of carbon dioxide and an aqueous surfactant, and (3) in situ deposition of chemical precipitates. 22 refs., 14 figs., 6 tabs.

Not Available

1986-10-01

279

Displacement and Adolescent Suicide: Introduction to a Special Section  

Microsoft Academic Search

Empirical findings from previous studies indicate that the risk factors for adolescent suicide are multifaceted and likely the result of the interaction between individual and contextual risk factors. In this special section, we focus on one subdomain of risk factors for adolescent suicide, namely, displacement. During adolescence, experiences of displacement due to changes in family or peer relationships may be

Manfred H. M. van Dulmen; Robert M. Bossarte; Monica H. Swahn

2011-01-01

280

Displacement Measurement and Its Application in Interframe Image Coding  

Microsoft Academic Search

A new technique for estimating interframe displacement of small blocks with minimum mean square error is presented. An efficient algorithm for searching the direction of displacement has been described. The results of applying the technique to two sets of images are presented which show 8-10 dB improvement in interframe variance reduction due to motion compensation. The motion compensation is applied

JASWANT R. JAIN; ANIL K. JAIN

1981-01-01

281

An Analysis of Dynamic Displacements Measured Within Pavement Structures.  

National Technical Information Service (NTIS)

A mathematical model was developed for representing the measured displacement vector fields in thirty test sections at the Research Annex at Texas A and M University. While the model predicted the displacements fairly well in each test section, it was obv...

F. H. Scrivner W. M. Moore

1973-01-01

282

Variable displacement blower  

DOEpatents

A blower having a stationary casing for rotatably supporting a rotor assembly having a series of open ended chambers arranged to close against the surrounding walls of the casing. Pistons are slidably mounted within each chamber with the center of rotation of the pistons being offset in regard to the center of rotation of the rotor assembly whereby the pistons reciprocate in the chambers as the rotor assembly turns. As inlet port communicates with the rotor assembly to deliver a working substance into the chamber as the pistons approach a top dead center position in the chamber while an outlet port also communicates with the rotor to exhaust the working substance as the pistons approach a bottom dead center position. The displacement of the blower is varied by adjusting the amount of eccentricity between the center of rotation of the pistons and the center of rotation of the rotor assembly.

Bookout, Charles C. (Niskayuna, NY); Stotts, Robert E. (Clifton Park, NY); Waring, Douglass R. (Ballston Spa, NY); Folsom, Lawrence R. (Ohain, BE)

1986-01-01

283

Disconnection of coronal field lines due to the emergence of new photospheric flux as the cause of CMEs and interplanetary shocks  

Microsoft Academic Search

A scenario is presented whereby CMEs and interplanetary shocks are consequences of a large scale rearrangement of the coronal magnetic field induced by the disconnection of field lines from the solar surface due to the emergence of flux with opposite polarity. In this scenario the CME is the mass released from the previously closed structure and the interplanetary shock is

S. Bravo

1996-01-01

284

Incorporation of the effect of the composite electric fields of molecular ions as a simulation tool for biological damage due to heavy-ion irradiation  

SciTech Connect

This paper presents a theoretical study of the DNA damage due to the effect of the composite electric fields of H{sub 2}O{sup +} ions produced from the irradiation of a heavy ion onto a cell. A model for atomic and molecular processes in strong electric fields is developed. It is found that the composite electric fields increase the number of events of electron-impact ionization processes. This may promote DNA damage.

Moribayashi, Kengo [Quantum Beam Science Directorate, Japan Atomic Energy Agency, 8-1-7 Umemidai, Kizugawa-City, Kyoto 619-0215 (Japan) and Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe City, Kyoto 610-0394 (Japan)

2011-07-15

285

Protein–water displacement distributions  

Microsoft Academic Search

The statistical properties of fast protein–water motions are analyzed by dynamic neutron scattering experiments. Using isotopic exchange, one probes either protein or water hydrogen displacements. A moment analysis of the scattering function in the time domain yields model-independent information such as time-resolved mean square displacements and the Gauss-deviation. From the moments, one can reconstruct the displacement distribution. Hydration water displays

Wolfgang Doster; Marcus Settles

2005-01-01

286

MRI of displaced meniscal fragments.  

PubMed

A torn meniscus frequently requires surgical fixation or debridement as definitive treatment. Meniscal tears with associated fragment displacement, such as bucket handle and flap tears, can be difficult to recognize and accurately describe on MRI, and displaced fragments can be challenging to identify at surgery. A displaced meniscal fragment can be obscured by synovium or be in a location not usually evaluated at arthroscopy. We present a pictorial essay of meniscal tears with displaced fragments in patients referred to a pediatric hospital in order to increase recognition and accurate interpretation by the radiologist, who in turn can help assist the surgeon in planning appropriate therapy. PMID:21863288

Dunoski, Brian; Zbojniewicz, Andrew M; Laor, Tal

2011-08-24

287

Ureteral Displacement due to a Migrated Intrauterine Contraceptive Device  

Microsoft Academic Search

Perforation of the uterus is rare but potentially fatal. During puerperium when the uterus is small and its wall is thin, the risk of perforation increases. We report a rare complication from an intrauterine contraceptive device (IUD) which caused deviation of the right ureter in a 31-year-old woman who presented with complaints of insomnia and abdominal pain. Our case shows

Akif Sirikci; Kemal Sarica; Metin Bayram

2000-01-01

288

Monitoring pipe line stress due to ground displacement  

SciTech Connect

Northwest Pipeline Corp. has a large-diameter natural gas pipe line system from Ignacio, Colo., to Sumas, Wash. At Douglas Pass in Colorado, large landslides required several sections of the line to be relocated outside the slide areas: 4,400 ft of new line in April 1962 and 3,200 ft in March 1963. No serious disruptions occurred for the next 16 years. Then in July 1979, some 1,200 ft had to be relocated. From 1980 to date, many landslides in the Douglas Pass area have caused new deformations, with the springs of 1983 and 1984 being the worst years. In 1980, Northwest Pipeline began engineering and geotechnical studies of the landslide problems. These led to instrumentation and pipe monitoring which indicated that pipe failure can be predicted and prevented if important slope deformations or increases in pipe stresses are detected early enough to implement some mitigating measures. Excavation of the pipe to relieve the stresses was used in most cases. The method was so successful that no pipe failure occurred in 1984 within instrumented sections, in spite of the exceptionally bad climatic conditions experienced.

Greenwood, J.H. Jr.

1986-04-01

289

Displacement of large-scale open solar magnetic fields from the zone of active longitudes and the heliospheric storm of November 3-10, 2004: 2. "Explosion" of singularity and dynamics of sunspot formation and energy release  

NASA Astrophysics Data System (ADS)

A more detailed scenario of one stage (August-November 2004) of the quasibiennial MHD process "Origination ... and dissipation of the four-sector structure of the solar magnetic field" during the decline phase of cycle 23 has been constructed. It has been indicated that the following working hypothesis on the propagation of an MHD disturbance westward (in the direction of solar rotation) and eastward (toward the zone of active longitudes) with the displacement of the large-scale open solar magnetic field (LOSMF) from this zone can be constructed based on LOSMF model representations and data on sunspot formation, flares, active filaments, and coronal ejections as well as on the estimated contribution of sporadic energy release to the flare luminosity and kinetic energy of ejections: (1) The "explosion" of the LOSMF singularity and the formation in the explosion zone of an anemone active region (AR), which produced the satellite sunspot formation that continued west and east of the "anemone," represented a powerful and energy-intensive source of MHD processes at this stage. (2) This resulted in the origination of two "governing" large-scale MHD processes, which regulated various usual manifestations of solar activity: the fast LOSMF along the neutral line in the solar atmosphere, strongly affecting the zone of active longitudes, and the slow LOSMF in the outer layers of the convection zone. The fronts of these processes were identified by powerful (about 1031 erg) coronal ejections. (3) The collision of a wave reflected from the zone of active longitudes with the eastern front of the hydromagnetic impulse of the convection zone resulted in an increase in LOSMF magnetic fluxes, origination of an active sector boundary in the zone of active longitudes, shear-convergent motions, and generation and destabilization of the flare-productive AR 10696 responsible for the heliospheric storm of November 3-10, 2004.

Ivanov, K. G.

2010-12-01

290

Uniform near-field nanopatterning due to the field distribution control by oblique femtosecond laser irradiation to silicon and gold nanoparticles  

Microsoft Academic Search

We present near-field optical properties around silicon and gold nanoparticles aligned on a silicon substrate excited by oblique incidence femtosecond laser for nanohole processing. Near-field nanofabrication will open up smart applications for new optical devices with high-throughput processing. The near field around silicon and gold particles is explained by Mie scattering theory, while the near field around gold nanoparticles is

Tomoya Miyanishi; Mitsuhiro Terakawa; Minoru Obara

2011-01-01

291

CHARACTER DISPLACEMENT IN POLYPHENIC TADPOLES  

Microsoft Academic Search

Biologists have long known that closely related species are often phenotypically different where they occur together, but are indistinguishable where they occur alone. The causes of such character displacement are controversial, however. We used polyphenic spadefoot toad tadpoles (Spea bombifrons and S. multiplicata) to test the hypothesis that character displacement evolves to minimize competition for food. We also sought to

David W. Pfennig; Peter J. Murphy

2000-01-01

292

Polar twilight UV-visible radiation field: Perturbations due to multiple scattering, ozone depletion, stratospheric clouds, and surface albedo  

SciTech Connect

The polar twilight atmosphere is different from that at mid-latitude in several ways which lead to significant changes in the wavelength-dependent radiation field. Ozone depletion in the stratosphere leads to increased scattering below 340 nm. Polar stratospheric clouds produce changes in the radiation field which depend on cloud height and thickness. A surface albedo near unity produces a large increase in scattering. Multiple scattering becomes a larger percentage of the radiation field as solar zenith angle increases. These perturbations on the radiation field lead to enhanced ozone destruction in the stratosphere, increased surface irradiance, and a significant wavelength-dependent increase in nadir radiance.

Anderson, D.E., Jr. (Naval Research Lab., Washington, DC (United States)); Lloyd, S.A. (Harvard Univ., Cambridge, MA (United States))

1990-05-20

293

Displacement cascades in diatomic materials  

SciTech Connect

A new function, the specified-projectile displacement function p/sub ijk/ (E), is introduced to describe displacement cascades in polyatomic materials. This function describes the specific collision events that produce displacements and hence adds new information not previously available. Calculations of p/sub ijk/ (E) for MgO, Al/sub 2/O/sub 3/ and TaO are presented and discussed. Results show that the parameters that have the largest effect on displacement collision events are the PKA energy and the mass ratio of the atom types in the material. It is further shown that the microscopic nature of the displacement events changes over the entire recoil energy range relevant to fusion neutron spectra and that these changes are different in materials whose mass ratio is near one than in those where it is far from one.

Parkin, D.M.; Coulter, C.A.

1981-01-01

294

Non-Abelian Permittivity of Quark-Gluon Plasma Due to the Self-Interaction of Field  

Microsoft Academic Search

From the semiclassical kinetic equations and the mean field equation of quark-gluon plasma, the contribution of the color field self-coupling to the non-Abelian permittivity at the leading order in the weak coupling constant is analyzed. The nonlinear frequency drift has been estimated for the k=0 modes.

Ji-Sheng Chen; Jia-Rong Li

2000-01-01

295

Riesgo laboral y residencial por exposición a campos electromagnéticos Labour and residential risk due to electromagnetic fields exposition  

Microsoft Academic Search

In the recent years, there has been an increment of ex- position to electromagnetic fields (EMF), specially residen- tial and labour exposure. Some scientist allege that exposure to electric and mag- netic fields generated mainly by electric power delivery sys- tems is responsible for health problems as reproductive dys- function, birth defects, neurological disorders and cancer. This article provides a

M. Física; Pastor Vega

296

The effect of visual training for patients with visual field defects due to brain damage: a systematic review  

Microsoft Academic Search

The objective of this review was to evaluate whether systematic visual training leads to (1) a restitution of the visual field (restoration), (2) an increase in the visual search field size or an improvement in scanning strategies (compensation) and (3) a transfer of training-related improvements in activities of daily living such as reading. To retrieve relevant publications, computer-aided searches of

Lies Bouwmeester; Joost Heutink; Cees Lucas

2007-01-01

297

Apes communicate about absent and displaced objects: methodology matters.  

PubMed

Displaced reference is the ability to refer to an item that has been moved (displaced) in space and/or time, and has been called one of the true hallmarks of referential communication. Several studies suggest that nonhuman primates have this capability, but a recent experiment concluded that in a specific situation (absent entities), human infants display displaced reference but chimpanzees do not. Here, we show that chimpanzees and bonobos of diverse rearing histories are capable of displaced reference to absent and displaced objects. It is likely that some of the conflicting findings from animal cognition studies are due to relatively minor methodological differences, but are compounded by interpretation errors. Comparative studies are of great importance in elucidating the evolution of human cognition; however, greater care must be taken with methodology and interpretation for these studies to accurately reflect species differences. PMID:23681052

Lyn, Heidi; Russell, Jamie L; Leavens, David A; Bard, Kim A; Boysen, Sarah T; Schaeffer, Jennifer A; Hopkins, William D

2013-05-17

298

Fitting Strains and Displacements by Minimizing Dislocation Energy  

Microsoft Academic Search

We present a procedure for matching a displacement field to a given strain field, or vice- versa, over an arbitrary domain, which can be a finite element. The fitting criterion used is minimization of a dislocation energy functional. The strain field, whether given or fitted, need not be compatible. The method has four immediate applications: (i) finite element stiffness formulation

Carlos A. Felippa; K. C. Park

299

Displaced Arab Families: Mothers' Voices on Living and Coping in Postwar Beirut  

Microsoft Academic Search

This study explores the experiences and views of women and their families who have been affected by displacement due to the Lebanese civil war. Despite the popular notion that displaced families have returned home, the effects of displacement continue to be felt by families, especially the women. Findings from in-depth interviews with women currently residing in two suburbs of Beirut

Jihad Makhoul; Mary Ghanem

2009-01-01

300

Measurement of Radiated Electromagnetic Field due to Low Voltage ESD with Spherical Electrode in 1-3GHz Frequency Bandwidth  

NASA Astrophysics Data System (ADS)

The micro-gap discharge as the low voltage ESD shows very fast transition-duration of about 32 ps or less. Furthermore, the breakdown field strength in the gap was very high of about 80 MV/m in low voltage discharging of below 400V. The relationship between the breakdown field strength in the gap and the amplitude of radiated electromagnetic field was examined in experimental study. The amplitude of radiated electromagnetic field was proportion to the breakdown field strength at the gap in the resonance experimental system using the discharge electrode with dipole configuration. In this time, we present an improved experimental system to measure the amplitude of radiated electromagnetic filed in more wideband region using spherical electrodes and a horn antenna. As a result, the amplitude of radiated electromagnetic field is proportion to the discharge voltage from 300V to 620V, and the amplitude of radiated electromagnetic field was according to the diameter of spherical electrode in 1-3GHz frequency bandwidth.

Kawamata, Ken; Minegishi, Shigeki; Fujiwara, Osamu

301

Electromagnetic Fields and Relative Heating Patterns Due to a Rectangular Aperture Source in Direct Contact with Bilayered Biological Tissue  

Microsoft Academic Search

Expressions are derived and evaluated for the electro-magnetic fields and associated relative heating patterns in two-Iayered biological tissue media exposed to a direct-contact rectangular aperture source. The source consists of a linearly polarized electric field distribution specified in the plane of the aperture. The results may be used for many biomedical applications ranging from the design of diathermy applicators to

A. W. Guy

1968-01-01

302

Diamagnetic fields due to finite-dimension intense beams in high-gain free-electron lasers  

Microsoft Academic Search

High-gain, self-amplified spontaneous emission free-electron lasers (SASE FEL's), with proposed operation in wavelengths extending down to x rays, require intense relativistic electron beams, which under certain conditions can generate large diamagnetic fields. The action of these fields has the potential to seriously degrade FEL performance. It is shown here by both analysis and simulation that the finite size of the

J. B. Rosenzweig; P. Musumeci

1998-01-01

303

A 3D electrokinetic flow structure of solution displacement in microchannels for on-chip sample preparation applications  

NASA Astrophysics Data System (ADS)

Electroosmotic flow with solution displacement in microchannels is often encountered in many lab-on-a-chip devices where washing procedures are designed using one solution to displace another different solution. In order to investigate the detailed flow structures for a displacement process between two different electrolyte solutions, a three-dimensional numerical model is developed in this paper. KCl solution and LaCl3 solution are used as sample solutions. A 2 mm long straight microchannel with a rectangular cross-sectional area (height 100 µm and width 200 µm) was employed in this study. The governing equations of the applied electrical field, flow field and concentration field are numerically solved based on a finite-control-volume scheme. The fluid flow coupled equations are solved using the semi-implicit method for pressure-linked equation (SIMPLE) algorithm. The observed electrokinetic flow structures include back flow in the center of the channel and distortion of the plug-like electroosmotic velocity profile, which are investigated in detail. It is found that distortion in the flow field is due to the induced pressure gradient, which results from the nonuniformity of electroosmotic mobilities and electrical conductivities of the two solutions. Finally, the displacement between a pair of different solutions, distilled ultra-filtered (DIUF) water and LaCl3 solution, is briefly studied.

Shao, Zhanjie; Ren, Carolyn L.; Schneider, Gerry E.

2006-03-01

304

Borehole optical lateral displacement sensor  

DOEpatents

There is provided by this invention an optical displacement sensor that utilizes a reflective target connected to a surface to be monitored to reflect light from a light source such that the reflected light is received by a photoelectric transducer. The electric signal from the photoelectric transducer is then imputed into electronic circuitry to generate an electronic image of the target. The target`s image is monitored to determine the quantity and direction of any lateral displacement in the target`s image which represents lateral displacement in the surface being monitored. 4 figs.

Lewis, R.E.

1998-10-20

305

Small-scale reconnection due to lower-hybrid drift instability in current sheets with sheared fields  

SciTech Connect

The consequences of small-scale lower-hybrid drift (LHD) instability for reconnection through thin current sheets are investigated in dependence on guide magnetic field B{sub y0} by three-dimensional Vlasov-code simulations. The LHD waves are amplified by inverse resonant Landau damping on ion flow. In current sheets separating antiparallel magnetic fields the LHD waves can trigger global current-aligned eigenmodes, which directly couple to the tearing-mode instability. Depending on the initial conditions either small-scale, three-dimensional, or small-scale two-dimensional reconnection prevails. In the presence of a moderate guide magnetic field up to B{sub y0}=B{sub 0}, where B{sub 0} is the asymptotic B{sub x} field, the unstable LHD waves propagate obliquely to the current direction, at different angles from the opposite sides of the current sheet. The resulting patchy three-dimensional small-scale reconnection grows significantly slower, compared to reconnection in antiparallel fields.

Silin, I.; Buechner, J. [Max-Planck-Institut fuer Sonnensystemforschung, Katlenburg-Lindau (Germany)

2005-01-01

306

Demonstrations for the effect of composite electric fields of molecular ions on the motion of secondary electrons due to ion irradiation  

NASA Astrophysics Data System (ADS)

The present simulation demonstrates the energy loss of each individual secondary electron due to the composite electric field formed from molecular ions. Both of the secondary electron and molecular ions are produced from an incident ion impact ionization process. The initial conditions of the secondary electron under which this electron is trapped near the trajectory are found for a proton and a carbon ion.

Moribayashi, Kengo

2013-11-01

307

SoilFlex: A model for prediction of soil stresses and soil compaction due to agricultural field traffic including a synthesis of analytical approaches  

Microsoft Academic Search

Soil compaction is one of the most important factors responsible for soil physical degradation. Soil compaction models are important tools for controlling traffic-induced soil compaction in agriculture. A two-dimensional model for calculation of soil stresses and soil compaction due to agricultural field traffic is presented. It is written as a spreadsheet that is easy to use and therefore intended for

Thomas Keller; Pauline Défossez; Peter Weisskopf; Johan Arvidsson; Guy Richard

2007-01-01

308

Using CIDS with Displaced Workers.  

ERIC Educational Resources Information Center

|Discusses the use of the Virginia Vital Information for Education and Work program at J. Sargeant Reynolds Community College, with particular emphasis on career planning and placement services and outreach efforts. Highlights special displaced workers programs with industry. (DMM)|

Amburgey, Lillian; Sanborn, Carleton H.

1987-01-01

309

Collateral damage: Evolution with displacement of fracture distribution and secondary fault strands in fault damage zones  

NASA Astrophysics Data System (ADS)

We investigate the development of fracture distributions as a function of displacement to determine whether damage around small and large faults is governed by the same process. Based on our own field work combined with data from the literature, we find that (1) isolated single faults with small displacements have macrofracture densities that decay as r-0.8, where r is distance from the fault plane, (2) mature fault damage zones can be interpreted as a superposition of these r-0.8 decays from secondary fault strands, resulting in an apparently more gradual decay with distance, and (3) a change in apparent decay and fault zone thickness becomes evident in faults that have displaced more than ˜150 m. This last observation is consistent with a stochastic model where strand formation is related to the number of fractures within the damage zone, which in turn is a function of displacement. These three observations together suggest that the apparent break in scaling between small and large faults is due to the nucleation of secondary faults and not a change in process.

Savage, Heather M.; Brodsky, Emily E.

2011-03-01

310

Enhanced electro-magnetic energy transfer between a hot and cold body at close spacing due to evanescent fields.  

National Technical Information Service (NTIS)

Theoretical studies have demonstrated that the energy transfer between a hot and cold body at close spacing (on the order of the radiation wavelength) can greatly exceed the limit for black body radiation (ie, Power = (sigma)T(sup 4)). This effect, due to...

J. E. Raynolds

1998-01-01

311

The Dispersion of the Geomagnetic Field Due to Secular Variation and Its Determination for Remote Times from Paleomagnetic Data  

Microsoft Academic Search

In studies of the paleosecular variation the situation often arises that, although a number of spot readings of the palcogeomagnetic field have been deduced from the fossil magnetization of a rock formation, their stratigraphic sequence is unknown. Hence, in this paper, methods are discussed of deducing the amount of dispersion produced by the palcosecu- lar variation in the magnetization of

K. M. Creer

1962-01-01

312

The uncertainty of the Uranian radio source location due to the nonuniqueness of the planetary magnetic field model  

Microsoft Academic Search

Since the Voyager 2 encounter in early 1986, several investigators have attempted to localize the source regions of the smooth high-frequency radio emission which was observed by the planetary radio astronomy experiment at the nightside of Uranus. The various studies [most of them are based on the offset tilted dipole (OTD) model of the Uranian magnetic field] yielded significantly different

H. P. Ladreiter; W. Macher; G. K. F. Rabl; H. O. Rucker

1993-01-01

313

The Effects of an Induced Electric Dipole Moment due to Earth's Electric Field on the Artificial Satellites Orbit  

NASA Astrophysics Data System (ADS)

The orbits of artificial satellites are very sensitive to a large number of disturbances, whose effects add to the main force exerted by Earth's gravitational field. The most important perturbations, caused by solar radiation pressure, the Moon and the Sun gravitational fields, have been extensively discussed in the literature, and must be taken into account in order to correct the orbital motion, to prevent collisions between satellites in close orbits. In this paper we consider an additional source of acceleration arising from an electric dipole moment induced by the high altitude Earth electric field in a metallic satellite of spherical shape. The order of magnitude of such effect is estimated to be in the range of 10 - 23m/s2. It is emphasized that the electric dipole moment effect(EDME) is dependent on the satellite shape and geometry and proportional to E_0 v/r^4. The Earth electric field E 0 is largely influenced by atmospheric electromagnetic phenomena, such as whistler waves and thunderstorms.

Heilmann, Armando; Ferreira, Luiz Danilo Damasceno; Dartora, Cesar Augusto

2012-04-01

314

Clavicle fracture with intrathoracic displacement.  

PubMed

Clavicle fractures are common, and most are isolated injuries. Injury to the nearby subclavian vessels and brachial plexus have classically been described as potential complications of clavicle fractures. However, in the setting of a substantially displaced clavicle fracture, concomitant thoracic trauma is relatively frequent. Injury to the thorax can be difficult to identify on physical examination, and advanced imaging modalities may be required for diagnosis. The evaluation, workup, and management of a patient with intrathoracic displacement of a clavicle fracture are described. Despite the significant fracture displacement and associated pneumothorax, the injury severity was not clinically obvious. Imaging, including a screening chest radiograph and subsequent axial computed tomography, played an important role in diagnosis and management. The patient underwent successful open reduction and plate fixation. A thoracostomy tube was not required at any point during the hospitalization. The patient recovered uneventfully and returned to full work duty by 3 months postoperatively. Including the current report, only 3 cases of intrathoracic displacement of the clavicle have been published in the English literature. All involved fractures of the middle third of the clavicle. The severity of displacement was not obvious in any patient, and diagnosis was dependent on additional imaging. Given the frequency of associated chest trauma and limitations of physical examination, chest radiography should be considered in the evaluation of patients with substantially displaced clavicle fractures. PMID:23937761

Lohse, Grant R; Lee, Donald H

2013-08-01

315

Correcting capacitive displacement measurements in metrology applications with cylindrical artifacts  

Microsoft Academic Search

Metrology applications commonly require non-contact, capacitive sensors for displacement measurements due to their nanometer resolution. In some metrology applications, for example, the measurement of roundness and spindle error motion, the displacements of stationary and rotating cylindrical artifacts are measured. Error from using a conventionally calibrated sensor with a non-flat (e.g., cylindrical) target is typically neglected, but these errors cannot be

Philip T. Smith; R. Ryan Vallance; Eric R. Marsh

2005-01-01

316

DEM Simulated Results And Seismic Interpretation of the Red River Fault Displacements in Vietnam  

NASA Astrophysics Data System (ADS)

The Song Hong basin is the largest Tertiary sedimentary basin in Viet Nam. Its onset is approximately 32 Ma ago since the left-lateral displacement of the Red River Fault commenced. Many researches on structures, formation and tectonic evolution of the Song Hong basin have been carried out for a long time but there are still remained some problems that needed to put into continuous discussion such as: magnitude of the displacements, magnitude of movement along the faults, the time of tectonic inversion and right lateral displacement. Especially the mechanism of the Song Hong basin formation is still in controversy with many different hypotheses due to the activation of the Red River fault. In this paper PFC2D based on the Distinct Element Method (DEM) was used to simulate the development of the Red River fault system that controlled the development of the Song Hong basin from the onshore to the elongated portion offshore area. The numerical results show the different parts of the stress field such as compress field, non-stress field, pull-apart field of the dynamic mechanism along the Red River fault in the onshore area. This propagation to the offshore area is partitioned into two main branch faults that are corresponding to the Song Chay and Song Lo fault systems and said to restrain the east and west flanks of the Song Hong basin. The simulation of the Red River motion also showed well the left lateral displacement since its onset. Though it is the first time the DEM method was applied to study the deformation and geodynamic evolution of the Song Hong basin, the results showed reliably applied into the structural configuration evaluation of the Song Hong basin.

Bui, H. T.; Yamada, Y.; Matsuoka, T.

2005-12-01

317

Dispersive effects of transverse displacements of SLC Arc magnets  

SciTech Connect

The SLC Arc magnets are subject to random displacements and field errors resulting in unpredictable transverse displacement of the central trajectory from that of the design. The chosen method of correcting this perturbed trajectory in the SLC Arcs utilizes mechanical movement of the combined function magnets which compose the Arc transport lines. Here we present the results of a recent investigation substantiating the earlier results which led to the adoption of this method.

Murray, J.J.; Fieguth, T.; Kheifets, S.

1986-07-23

318

On the Energy Level Shifts of Atoms due to the Interaction between the Electron and the Electromagnetic Field  

Microsoft Academic Search

It was ascertained, by the experiment of Lamb and Retherford, that the 2S 12\\/2 and 2P 1\\/2 levels of hydrogen, which are necessarily expected, from Dirac's theory, to coincide, are actually separated by about 1000 M cycles; and it has ever since been attempted by Bethe and many other authors to interprete this as being due to the interaction between

O. Hara; T. Tokano

1949-01-01

319

Trends in the F2 ionospheric layer due to long-term variations in the Earth's magnetic field  

Microsoft Academic Search

The Earth's magnetic field presents long-term variations with changes in strength and orientation. Particularly, changes in the dip angle (I) and, consequently, in the sin(I)cos(I) factor, affect the thermospheric neutral winds that move the conducting plasma of the ionosphere. In this way, a lowering or lifting of the F2-peak (hmF2) is induced together with changes in foF2, depending on season,

Ana G. Elias

2009-01-01

320

Contactless sub-millimeter displacement measurements  

NASA Astrophysics Data System (ADS)

Weather effects on foldable domes, as used at the DOT and GREGOR, are investigated, in particular the correlation between the wind field and the stresses caused to both metal framework and tent clothing. Camera systems measure contactless the displacement of several dome points. The stresses follow from the measured deformation pattern. The cameras placed near the dome floor do not disturb telescope operations. In the set-ups of DOT and GREGOR, these cameras are up to 8 meters away from the measured points and must be able to detect displacements of less than 0.1 mm. The cameras have a FireWire (IEEE1394) interface to eliminate the need for frame grabbers. Each camera captures 15 images of 640 × 480 pixels per second. All data is processed on-site in real-time. In order to get the best estimate for the displacement within the constraints of available processing power, all image processing is done in Fourier-space, with all convolution operations being pre-computed once. A sub-pixel estimate of the peak of the correlation function is made. This enables to process the images of four cameras using only one commodity PC with a dual-core processor, and achieve an effective sensitivity of up to 0.01 mm. The deformation measurements are well correlated to the simultaneous wind measurements. The results are of high interest to upscaling the dome design (ELTs and solar telescopes).

Sliepen, Guus; Jägers, Aswin P. L.; Bettonvil, Felix C. M.; Hammerschlag, Robert H.

2008-07-01

321

Effects due to finite values of the temperature and the chemical potential in some two-dimensional field models  

SciTech Connect

A study is made in the mean field approximation of the ground-state structure of the Gross-Neveu model as N /yields/ /infinity/ and the two-dimensional (1 + 1) /var phi//sup 4/ model with fermions at finite values of the temperature T and chemical potential /alpha/ of the fermions. The critical values T/sub c/ and /alpha//sub c/ at which the symmetry of the system, which is spontaneously broken at T = /alpha/ = 0, is restored are obtained. The possibility of using the obtained results to describe the physical property is of quasione-dimensional systems in the theory of condensed media is discussed.

Osipov, V.A.; Fedyanin, V.K.

1988-06-01

322

Development of a Wireless Displacement Measurement System Using Acceleration Responses  

PubMed Central

Displacement measurements are useful information for various engineering applications such as structural health monitoring (SHM), earthquake engineering and system identification. Most existing displacement measurement methods are costly, labor-intensive, and have difficulties particularly when applying to full-scale civil structures because the methods require stationary reference points. Indirect estimation methods converting acceleration to displacement can be a good alternative as acceleration transducers are generally cost-effective, easy to install, and have low noise. However, the application of acceleration-based methods to full-scale civil structures such as long span bridges is challenging due to the need to install cables to connect the sensors to a base station. This article proposes a low-cost wireless displacement measurement system using acceleration. Developed with smart sensors that are low-cost, wireless, and capable of on-board computation, the wireless displacement measurement system has significant potential to impact many applications that need displacement information at multiple locations of a structure. The system implements an FIR-filter type displacement estimation algorithm that can remove low frequency drifts typically caused by numerical integration of discrete acceleration signals. To verify the accuracy and feasibility of the proposed system, laboratory tests are carried out using a shaking table and on a three storey shear building model, experimentally confirming the effectiveness of the proposed system.

Park, Jong-Woong; Sim, Sung-Han; Jung, Hyung-Jo; Spencer, Billie F.

2013-01-01

323

Generation of displaced squeezed superpositions of coherent states  

SciTech Connect

We study the method of generation of states that approximate superpositions of large-amplitude coherent states (SCSs) with high fidelity in free-traveling fields. Our approach is based on the representation of an arbitrary single-mode pure state, and SCSs in particular, in terms of displaced number states with an arbitrary displacement amplitude. The proposed optical scheme is based on alternation of photon additions and displacement operators (in the general case, N photon additions and N - 1 displacements are required) with a seed coherent state to generate both even and odd displaced squeezed SCSs regardless of the parity of the used photon additions. It is shown that the optical scheme studied is sensitive to the seed coherent state if the other parameters are unchanged. Output states can approximate either even squeezed SCS or odd SCS shifted relative to each other by some value. This allows constructing a local rotation operator, in particular, the Hadamard gate, which is a mainframe element for quantum computation with coherent states. We also show that three-photon additions with two intermediate displacement operators are sufficient to generate even displaced squeezed SCS with the amplitude 1.7 and fidelity more than 0.99. The effects deteriorating the quality of output states are considered.

Podoshvedov, S. A., E-mail: sapo66@mail.ru [South Ural State University, Department of General and Theoretical Physics (Russian Federation)

2012-03-15

324

Far-field self-focusing and -defocusing radiation behaviors of the electroluminescent light sources due to negative refraction.  

PubMed

In recent years, researchers have demonstrated negative refraction theoretically and experimentally by pumping optical power into photonic crystal (PhC) or waveguide structures. The concept of negative refraction can be used to create a perfect lens that focuses an object smaller than the wavelength. By inserting two-dimensional PhCs into the peripheral of a semiconductor light emitting structure, this study presents an electroluminescent device with negative refraction in the visible wavelength range. This approach produces polarization dependent collimation behavior in far-field radiation patterns. The modal dispersion of negative refraction results in strong group velocity modulation, and self-focusing and -defocusing behaviors are apparent from light extraction. This study further verifies experimental results by using theoretic calculations based on equifrequency contours. PMID:23454956

Yin, Yu-Feng; Lin, Yen-Chen; Tsai, Tsung-Han; Shen, Yi-Chun; Huang, Jianjang

2013-01-15

325

Permeability enhancement due to cold water injection: A Case Study at the Los Azufres Geothermal Field, Mexico  

SciTech Connect

Pressure transient buildup and falloff data from 3 wells at the Los Azufres geothermal field have been evaluated to determine the extent to which cold water infection increases the permeability of the near-bore reservoir formation. Simultaneous analysis of the buildup and falloff data provides estimates of the permeability-thickness of the reservoir, the skin factor of the well, and the degree of permeability enhancement in the region behind the thermal front. Estimates of permeability enhancement range from a factor of 4 to 9, for a temperature change of about 150{degree}C. The permeability enhancement is attributed to thermally induced contraction and stress-cracking of the formation. 9 refs., 18 figs.

Benson, S.M.; Daggett, J.; Ortiz, J.; Iglesias, E. (Lawrence Berkeley Lab., CA (USA); Comision Federal de Electricidad, Morelia (Mexico); Instituto de Investigaciones Electricas, Cuernavaca (Mexico))

1989-04-01

326

Transient Phenomena of Current and Field Distortion due to Dynamics of Packet-Like Charges in LDPE Films  

NASA Astrophysics Data System (ADS)

Simultaneous measurements for space charge and external current were carried out using a PEA measurement system with an electrometer on the back of a grounding electrode in order to clarify physical situation of a huge packet of positive space charges in LDPE films. A large number of positive charges from semi-conduction anode were accumulated at the interface between LDPE and Al-cathode under 1.5MV/cm of mean applied field and then they finally disappeared. Results of the simultaneous measurements showed that the external current kept a relatively high value during the charge accumulation and it further increased when the charges disappeared. Both the charge dynamics and the external current were restricted by addition of a low-molecular-weight paraffin wax, indicating that the carrier transport was influenced by micro structure of the polymer. Dynamics of residual charges after short-circuiting is also discussed.

Yoshioka, Hirokazu; Kadowaki, Kazunori; Kitani, Isamu

327

F layer postsunset height rise due to electric field prereversal enhancement: 2. Traveling planetary wave ionospheric disturbances and their role on the generation of equatorial spread F  

Microsoft Academic Search

This paper investigates the role played by traveling planetary wave ionospheric disturbances (TPWIDs) on the modulation of the electric field prereversal enhancement (PRE) amplitude, near-sunset hours, in the equatorial ionosphere, and their influence on the day-to-day equatorial spread F (ESF) variability. We show that ``fresh'' (ESF) day-to-day variability is closely related with the postsunset height rise due to the electric

P. R. Fagundes; J. R. Abalde; J. A. Bittencourt; Y. Sahai; R. G. Francisco; V. G. Pillat; W. L. C. Lima

2009-01-01

328

F layer postsunset height rise due to electric field prereversal enhancement: 2. Traveling planetary wave ionospheric disturbances and their role on the generation of equatorial spread F  

Microsoft Academic Search

This paper investigates the role played by traveling planetary wave ionospheric disturbances (TPWIDs) on the modulation of the electric field prereversal enhancement (PRE) amplitude, near-sunset hours, in the equatorial ionosphere, and their influence on the day-to-day equatorial spread F (ESF) variability. We show that “fresh” (ESF) day-to-day variability is closely related with the postsunset height rise due to the electric

P. R. Fagundes; J. R. Abalde; J. A. Bittencourt; Y. Sahai; R. G. Francisco; V. G. Pillat; W. L. C. Lima

2009-01-01

329

Forest transition in Vietnam and displacement of deforestation abroad  

PubMed Central

In some countries across the globe, tropical forest cover is increasing. The national-scale reforestation of Vietnam since 1992 is assumed to contribute to this recovery. It is achieved, however, by the displacement of forest extraction to other countries on the order of 49 (34–70) M m3, or ?39% of the regrowth of Vietnam's forests from 1987 to 2006. Approximately half of wood imports to Vietnam during this period were illegal. Leakage due to policies restricting forest exploitation and displacement due to growing domestic consumption and exports contributed respectively to an estimated 58% and 42% of total displacement. Exports of wood products from Vietnam also grew rapidly, amounting to 84% of the displacement, which is a remarkable feature of the forest transition in Vietnam. Attribution of the displacement and corresponding forest extraction to Vietnam, the source countries or the final consumers is thus debatable. Sixty-one percent of the regrowth in Vietnam was, thus, not associated with displacement abroad. Policies allocating credits to countries for reducing deforestation and forest degradation should monitor illegal timber trade and take into account the policy-induced leakage of wood extraction to other countries.

Meyfroidt, Patrick; Lambin, Eric F.

2009-01-01

330

Photonic bandgap Bragg fiber sensors for bending/displacement detection.  

PubMed

We demonstrate an amplitude-based bending/displacement sensor that uses a plastic photonic bandgap Bragg fiber with one end coated with a silver layer. The reflection intensity of the Bragg fiber is characterized in response to different displacements (or bending curvatures). We note that the Bragg reflector of the fiber acts as an efficient mode stripper for the wavelengths near the edge of the fiber bandgap, which makes the sensor extremely sensitive to bending or displacements at these wavelengths. Besides, by comparison of the Bragg fiber sensor to a sensor based on a standard multimode fiber with similar outer diameter and length, we find that the Bragg fiber sensor is more sensitive to bending due to the presence of a mode stripper in the form of a multilayer reflector. Experimental results show that the minimum detection limit of the Bragg fiber sensor can be as small as 3 ?m for displacement sensing. PMID:24085096

Qu, Hang; Brastaviceanu, Tiberius; Bergeron, Francois; Olesik, Jonathan; Pavlov, Ivan; Ishigure, Takaaki; Skorobogatiy, Maksim

2013-09-01

331

Intensity and polarization of laser-induced fluorescence due to forbidden excitation of He atoms immersed in an electric field in plasmas  

NASA Astrophysics Data System (ADS)

Laser-induced fluorescence (LIF) processes through the Stark and electric-quadrupole moment (QDP) transitions of HeI (2S1?nD1?2P1,n=3,4) have been investigated for reliable electric-field measurements in plasmas. A linear-polarization model is formulated for various configurations of electric fields, magnetic fields, and laser polarization. To extend the model to higher-particle-density plasmas we develop a rate-equation model involving a collisional disalignment term. Disalignment rates of nD1 states, Rda , due to a collision with He gas were measured. Spatial distributions in intensity and polarization of LIF were observed in a discharge plasma. For n=3 with small Rda , the same electric-field distribution in the sheath was obtained from either of the intensity ratios of the Stark to QDP component and the polarization, and the sheath potential agreed well with that by an electric probe. For n=4 with large Rda , the distribution was also correctly obtained from partially depolarized LIF wave forms by using the extended model. These results show that our extended model provides an accurate measurement of the electric field. The minimum detectable field strength was 80V/cm for n=4 . Application and limitations of the methods are discussed.

Takiyama, K.; Furukawa, S.; Namba, S.; Oda, T.; Kawasaki, K.

2009-02-01

332

A wireless laser displacement sensor node for structural health monitoring.  

PubMed

This study describes a wireless laser displacement sensor node that measures displacement as a representative damage index for structural health monitoring (SHM). The proposed measurement system consists of a laser displacement sensor (LDS) and a customized wireless sensor node. Wireless communication is enabled by a sensor node that consists of a sensor module, a code division multiple access (CDMA) communication module, a processor, and a power module. An LDS with a long measurement distance is chosen to increase field applicability. For a wireless sensor node driven by a battery, we use a power control module with a low-power processor, which facilitates switching between the sleep and active modes, thus maximizing the power consumption efficiency during non-measurement and non-transfer periods. The CDMA mode is also used to overcome the limitation of communication distance, which is a challenge for wireless sensor networks and wireless communication. To evaluate the reliability and field applicability of the proposed wireless displacement measurement system, the system is tested onsite to obtain the required vertical displacement measurements during the construction of mega-trusses and an edge truss, which are the primary structural members in a large-scale irregular building currently under construction. The measurement values confirm the validity of the proposed wireless displacement measurement system and its potential for use in safety evaluations of structural elements. PMID:24084114

Park, Hyo Seon; Kim, Jong Moon; Choi, Se Woon; Kim, Yousok

2013-09-30

333

Increased particle transport due t resonant magnetic perturbations modelled with a vacuum field line tracing code and a 2D fluid code  

SciTech Connect

In this paper we compare the pedestal density changes in resonant magnetic perturbations (RMP) H-modes at low collisionality with enhanced free streaming due to the creation of open field lines. First, we derive the effective radial transport coefficients by matching an ELMing (edge localized mode) H-mode using SOLPS5. Next, a vacuum field line tracing code, TRIP3D, is employed to calculate free streaming of particles along open field lines inside the traditional 2D axisymmetric separatrix. These coefficients are added to the effective radial transport coefficients from the ELMing H-mode and inserted in SOLPS5 to compute midplane profiles. Finally, we compare the SOLPS5 results with the experimental data from RMP H-modes and find good agreement. This good agreement was achieved not only for one single case, but also for two different experiments, with different triangularities, where the high triangularity case contains two RMP H-modes that give good agreement.

Mordijck, S. [University of California, San Diego; Moyer, R. A. [University of California, San Diego

2010-01-01

334

Reexamination of relaxation of spins due to a magnetic field gradient: Identity of the Redfield and Torrey theories  

SciTech Connect

There is an extensive literature on magnetic-gradient-induced spin relaxation. Cates, Schaefer, and Happer, in a seminal publication, have solved the problem in the regime where diffusion theory (the Torrey equation) is applicable using an expansion of the density matrix in diffusion equation eigenfunctions and angular momentum tensors. McGregor has solved the problem in the same regime using a slightly more general formulation using the Redfield theory formulated in terms of the autocorrelation function of the fluctuating field seen by the spins and calculating the correlation functions using the diffusion-theory Green's function. The results of both calculations were shown to agree for a special case. In the present work, we show that the eigenfunction expansion of the Torrey equation yields the expansion of the Green's function for the diffusion equation, thus showing the identity of this approach with that of the Redfield theory. The general solution can also be obtained directly from the Torrey equation for the density matrix. Thus, the physical content of the Redfield and Torrey approaches are identical. We then introduce a more general expression for the position autocorrelation function of particles moving in a closed cell, extending the range of applicability of the theory.

Golub, R.; Rohm, Ryan M.; Swank, C. M. [Physics Department, North Carolina State University, Raleigh, North Carolina 27695 (United States); Physics Department, University of North Carolina, Chapel Hill, North Carolina 27599 (United States)

2011-02-15

335

Analyzing and correcting for contaminating magnetic fields at the Brorfelde geomagnetic observatory due to high voltage DC power lines  

NASA Astrophysics Data System (ADS)

The magnetic field observations made at the geomagnetic observatory Brorfelde (BFE), Denmark, are subject to disturbances of several nT caused by two single wire high-voltage DC power lines connecting Scandinavia with Central Europe. We have analysed how the magnetic disturbances relate to the currents in the power lines and found a linear relationship. Using linear regression on carefully selected parts of the available data series we have determined the factors of proportionality. Based on the simple relationship between the currents in the power lines and the observed magnetic disturbances, we have derived a method to correct the observatory data for a significant part of the disturbances. In addition we have investigated the influence of the disturbances on the determination of the K-index of the observatory. We found that the K-index based on the original disturbed data compared to the K-indices calculated from corrected data was different in 4 % of the 3-hour intervals for the investigated period.

Maule, C. Fox; Thejll, P.; Neska, A.; Matzka, J.; Pedersen, L. W.; Nilsson, A.

2009-11-01

336

Increased vascular permeability in the circumventricular organs of adult rat brain due to stimulation by extremely low frequency magnetic fields.  

PubMed

It has been demonstrated that the exposure of biological systems to magnetic fields (MFs) can produce several beneficial effects: tissue recovery in chronic wounds, re-establishment of blood circulation after tissue ischemia or in necrotic tissues, improvement after epileptic episodes, angiogenesis, etc. In the current study, the effects of extremely low frequency (ELF) MF on the capillaries of some circumventricular organs (CVOs) are demonstrated; a vasodilator effect is reported as well as an increase in their permeability to non-liposoluble substances. For this study, 96 Wistar male rats (250 g body mass) were used and divided into three groups of 32 rats each: a control group (no treatment); a sham ELF-MF group; and an experimental group subjected to ELF-MF (120 Hz harmonic waves and 0.66 mT, root mean square) by the use of Helmholtz coils. All animals were administered colloidal carbon (CC) intravenously to study, through optical and transmission electron microscopy, the capillary permeability in CVOs and the blood-brain barrier (BBB) in brain areas. An increase in capillary permeability to CC was detected in the ELF-MF-exposed group as well as a significant increase in vascular area (capillary vasodilation); none of these effects were observed in individuals of the control and sham ELF-MF groups. It is important to investigate the mechanisms involved in the phenomena reported here in order to explain the effects of ELF-MF on brain vasculature. PMID:23060261

Gutiérrez-Mercado, Yanet K; Cañedo-Dorantes, Luis; Gómez-Pinedo, Ulises; Serrano-Luna, Gregorio; Bañuelos-Pineda, Jacinto; Feria-Velasco, Alfredo

2012-10-11

337

Reexamination of relaxation of spins due to a magnetic field gradient: Identity of the Redfield and Torrey theories  

NASA Astrophysics Data System (ADS)

There is an extensive literature on magnetic-gradient-induced spin relaxation. Cates, Schaefer, and Happer, in a seminal publication, have solved the problem in the regime where diffusion theory (the Torrey equation) is applicable using an expansion of the density matrix in diffusion equation eigenfunctions and angular momentum tensors. McGregor has solved the problem in the same regime using a slightly more general formulation using the Redfield theory formulated in terms of the autocorrelation function of the fluctuating field seen by the spins and calculating the correlation functions using the diffusion-theory Green’s function. The results of both calculations were shown to agree for a special case. In the present work, we show that the eigenfunction expansion of the Torrey equation yields the expansion of the Green’s function for the diffusion equation, thus showing the identity of this approach with that of the Redfield theory. The general solution can also be obtained directly from the Torrey equation for the density matrix. Thus, the physical content of the Redfield and Torrey approaches are identical. We then introduce a more general expression for the position autocorrelation function of particles moving in a closed cell, extending the range of applicability of the theory.

Golub, R.; Rohm, Ryan M.; Swank, C. M.

2011-02-01

338

Multiple displacement motor driven power drive unit  

Microsoft Academic Search

A multiple displacement motor driven power drive unit having two separate hydraulic systems each with a variable displacement hydraulic motor having its output connected to a torque summing gear train. A control provides for operation of one or the other of the motors at full displacement while the other motor is at zero displacement and free-wheels. There is a manual

Burandt

1985-01-01

339

Sectoral Change and Worker Displacement.  

National Technical Information Service (NTIS)

The research addresses dislocated worker problems and provides a comprehensive view of worker displacement and its role in the evolution of unemployment patterns over the past twenty-five years. The first part of the study measures a aggregate rate of wor...

R. Topel K. Murphy S. Davis L. Katz

1990-01-01

340

Stochastic Microgeometry for Displacement Mapping  

Microsoft Academic Search

Creating surfaces with intricate small-scale features (mi- crogeometry) and detail is an important task in geomet- ric modeling and computer graphics. We present a model processing method capable of producing a wide variety of complex surface features based on displacement mapping and stochastic geometry. The latter is a branch of mathe- matics that analyzes and characterizes the statistical prop- erties

Craig A. Schroeder; David E. Breen; Christopher D. Cera; William C. Regli

2005-01-01

341

Job Displacement, Disability, and Divorce  

Microsoft Academic Search

Earnings shocks should affect divorce probability by changing a couple's expected gains from marriage. We find that the divorce hazard rises after a spouse's job displacement but does not change after a spousal disability. This difference casts doubt on a purely pecuniary motivation for divorce following earnings shocks, since both types of shocks exhibit similar long-run economic consequences. Furthermore, the

2004-01-01

342

Knowledge Integration and Displaced Volume  

Microsoft Academic Search

This study contrasted spontaneous and reflective knowledge integration instruction delivered using a computer learning environment to enhance understanding of displaced volume. Both forms of instruction provided animated experiments and required students to predict outcomes, observe results, and explain their ideas. In addition, the reflective instruction diagnosed specific inconsistencies in student reasoning and encouraged students to reflect on these dilemmas as

Marcia C. Linn; Bat-Sheva Eylon

2000-01-01

343

Mass Media Displacement and Saturation  

Microsoft Academic Search

This study addresses the contradiction between the theoretical displacement of incumbent media by new media versus empirical evidence of rising consumption of both new and incumbent media. By analyzing 4 years of biannual daypart media consumption surveys, this research reveals trends in the consumer use of advertiser-supported media in the United States. Large gains were seen in new media, such

Jay Newell; Joseph J. Pilotta; John C. Thomas

2008-01-01

344

Guest displacement in silicon clathrates  

Microsoft Academic Search

We study both theoretically and experimentally the structure of the doped silicon clathrate II NaxSi34. We find that contrary to published works, the sodium atoms do not retain the Td symmetry inside the Si28 cages and move about 1 Å away from the center of the cage. This displacement, in conjunction with that of a sodium atom in an adjacent

Florent Tournus; Bruno Masenelli; Patrice Mélinon; Damien Connétable; Xavier Blase; Anne Marie Flank; Pierre Lagarde; Christian Cros; Michel Pouchard

2004-01-01

345

RECREATION BENEFITS AND DISPLACED FACILITIES  

EPA Science Inventory

A new recreation site or improvement of an existing site results in an increase in demand for that site perhaps at the expense of substitute facilities. A brief literature review indicates differing views on how benefits from displaced facilities should be treated. The author dem...

346

Retraining Displaced Workers. Policy Brief  

ERIC Educational Resources Information Center

|Robert LaLonde of the University of Chicago and Daniel Sullivan of the Federal Reserve Bank of Chicago suggest that retraining through our nation's community colleges is a way to reduce the skills gaps of at least some of these displaced workers and increase their reemployment earnings. Although workers may still experience significant earnings…

LaLonde, Robert; Sullivan, Daniel

2010-01-01

347

Retraining Displaced Workers. Policy Brief  

ERIC Educational Resources Information Center

Robert LaLonde of the University of Chicago and Daniel Sullivan of the Federal Reserve Bank of Chicago suggest that retraining through our nation's community colleges is a way to reduce the skills gaps of at least some of these displaced workers and increase their reemployment earnings. Although workers may still experience significant earnings…

LaLonde, Robert; Sullivan, Daniel

2010-01-01

348

Uncertainties in Eddy Covariance fluxes due to post-field data processing: a multi-site, full factorial analysis  

NASA Astrophysics Data System (ADS)

Eddy Covariance (EC) is the only technologically available direct method to measure carbon and energy fluxes between ecosystems and atmosphere. However, uncertainties related to this method have not been exhaustively assessed yet, including those deriving from post-field data processing. The latter arise because there is no exact processing sequence established for any given situation, and the sequence itself is long and complex, with many processing steps and options available. However, the consistency and inter-comparability of flux estimates may be largely affected by the adoption of different processing sequences. The goal of our work is to quantify the uncertainty introduced in each processing step by the fact that different options are available, and to study how the overall uncertainty propagates throughout the processing sequence. We propose an easy-to-use methodology to assign a confidence level to the calculated fluxes of energy and mass, based on the adopted processing sequence, and on available information such as the EC system type (e.g. open vs. closed path), the climate and the ecosystem type. The proposed methodology synthesizes the results of a massive full-factorial experiment. We use one year of raw data from 15 European flux stations and process them so as to cover all possible combinations of the available options across a selection of the most relevant processing steps. The 15 sites have been selected to be representative of different ecosystems (forests, croplands and grasslands), climates (mediterranean, nordic, arid and humid) and instrumental setup (e.g. open vs. closed path). The software used for this analysis is EddyPro™ 3.0 (www.licor.com/eddypro). The critical processing steps, selected on the basis of the different options commonly used in the FLUXNET community, are: angle of attack correction; coordinate rotation; trend removal; time lag compensation; low- and high- frequency spectral correction; correction for air density fluctuations; and length of the flux averaging interval. We illustrate the results of the full-factorial combination relative to a subset of the selected sites with particular emphasis on the total uncertainty at different time scales and aggregations, as well as a preliminary analysis of the most critical steps for their contribution to the total uncertainties and their potential relation with site set-up characteristics and ecosystem type.

Sabbatini, S.; Fratini, G.; Arriga, N.; Papale, D.

2012-04-01

349

Effects of rotor eccentric displacements on performance of bearingless switched reluctance motors  

Microsoft Academic Search

This paper investigates effects of rotor eccentric radial displacements on magnetic field distribution, winding inductances, radial force and torque of BSRM. Magnetic field distributions of BSRM with different displacements of rotor eccentricity are calculated by 2-D finite element analysis. Then inductances of main and radial force windings, radial force and torque can be obtained, respectively. The calculated results testify that

Zeyuan Liu; Zhiquan Deng; Jun Cai; Xiaoyuan Chen; Shishan Wang; Xiangsheng Li

2009-01-01

350

Interfacial effects in oil displacements  

SciTech Connect

The surface stress-deformation behavior of some real phase interfaces, such as crude oil-brine interfaces, is believed to be viscoelastic. In an effort to provide a general framework for understanding such behavior, the author has proposed the simple surface material, for which the present stress is determined by the past history of only the surface deformation gradient. After considering the concept of isotropy, the author is led to isotropic simple surface materials and the simple surface fluid. The linear Boussinesq surface fluid is a limiting case of the simple surface fluid, for which the relaxation time of the surface is so short or the flow so slow that memory effects disappear. Both the measurement of surface viscoelastic behavior and its effect upon the entrapment and displacement of residual oil are discussed. Unstable foams are used for mobility control in the displacement of residual oil by carbon dioxide or nitrogen. A qualitative analysis is developed for the displacement of an unstable foam in a porous media. The effects of the magnitude of the London-van der Waals forces, of the surface tension, of the surface viscosities, of the quality (volume fraction of the gas), of the bubble size, and of the viscosity of the foaming agent solution are investigated. Finally, a statistical structural model is used in the context of local volume averaging to examine the effects of interfacial tension, the interfacial viscosities, and wetting upon the capillary pressure and relative permeability functions in an unsteady-state displacement. Within the immediate the neighborhood of a displacement front, simulations, especially of inhibitions, should employ unsteady-state relative permeabilities.

Ramamohan, T.R.

1985-01-01

351

Ultrasonic Tracking of Acoustic Radiation Force-Induced Displacements in Homogeneous Media  

PubMed Central

The use of ultrasonic methods to track the tissue deformation generated by acoustic radiation force is subject to jitter and displacement underestimation errors, with displacement underestimation being primarily caused by lateral and elevation shearing within the point spread function (PSF) of the ultrasonic beam. Models have been developed using finite element methods and Field II, a linear acoustic field simulation package, to study the impact of focal configuration, tracking frequency, and material properties on the accuracy of ultrasonically tracking the tissue deformation generated by acoustic radiation force excitations. These models demonstrate that lateral and elevation shearing underneath the PSF of the tracking beam leads to displacement underestimation in the focal zone. Displacement underestimation can be reduced by using tracking beams that are narrower than the spatial extent of the displacement fields. Displacement underestimation and jitter decrease with time after excitation as shear wave propagation away from the region of excitation reduces shearing in the lateral and elevation dimensions. The use of higher tracking frequencies in broadband transducers, along with 2D focusing in the elevation dimension, will reduce jitter and improve displacement tracking accuracy. Relative displacement underestimation remains constant as a function of applied force, while jitter increases with applied force. Underdeveloped speckle (SNR <1.91) leads to greater levels of jitter and peak displacement underestimation. Axial shearing is minimal over the tracking kernel lengths used in Acoustic Radiation Force Impulse (ARFI) imaging and thus does not impact displacement tracking.

Palmeri, Mark L.; McAleavey, Stephen A.; Trahey, Gregg E.; Nightingale, Kathryn R.

2007-01-01

352

Disability, displacement and public health: a vision for Haiti.  

PubMed

Refugees and internally displaced persons (IDPs) with disabilities are some of the most neglected and socially excluded groups within any population. Natural disasters are events that cause bodily harm resulting in disability and that result in the displacement of people. Many predict a continual increase of natural disasters in the future due to changing climates. People with disabilities constitute one of the most vulnerable social groups in the case of a natural disaster. In 2010, Haiti suffered a devastating earthquake leading to great social, health and economic hardship including the displacement of people with disabilities. Due to the very extent of the structural devastation Haiti experienced and the international focus on assisting Haitians who suffered injuries leading to disabilities, there is an opportunity for Haiti to become a model for future disaster management in terms of mainstreaming the needs of people with disabilities in the restoration, resettlement and reintegration process. PMID:21608390

Wolbring, Gregor

353

Reassociation rate limited displacement of DNA strands by branch migration.  

PubMed Central

Large branched DNA structures are constructed by two-step reassociation of separated complementary strands from restriction fragments of different lengths. The displacement of DNA strands initially annealed to longer complementary DNA sequences, a process mediated by branch migration, is very rapid and has thus far been followed only under conditions which are second order, DNA reassociation rate limiting. The average lifetime of branched DNA leading to displacement of 1.6 Kb strands is estimated to be less than 10 seconds under conditions of DNA reassociation, Tm-25 degrees C. Several DNA-binding drugs, including intercalating dyes, have been tested to determine their influence, if any, on the kinetics of DNA strand displacements by branch migration. Only actinomycin D was found to have significant effect under the conditions we have described. The kinetics of the strand displacement in the presence of low concentrations of actinomycin D remain second order and slower rate of strand displacement must be attributed to decreased rate of reassociation of DNA strands to form the branched intermediates. Consideration is given to the potential manipulation of DNA structures at site-directed branches and the limitations due to rapid strand displacements. The feasibility of constructing sufficiently large branched DNA regions to approach first order, branch migration rate limiting kinetics is also discussed. Images

Green, C; Tibbetts, C

1981-01-01

354

A new loss mechanism in graphene nanoresonators due to the synthetic electric fields caused by inherent out-of-plane membrane corrugations  

NASA Astrophysics Data System (ADS)

For the first time the influence of out-of-plane deformations, which always exist in graphene, on the non-stationary processes is considered for the case of a monolayer graphene nanoresonator. A new loss mechanism for this device caused by dissipative intra-valley currents stipulated by synthetic electric fields is studied. These fields are generated by time-dependent gauge fields arising in a graphene membrane due to its intrinsic out-of-plane distortions and the influence of the external periodic electromotive force. The corresponding formula for the quality factor has a quantum mechanical origin and includes quantum mechanical parameters. This loss mechanism accounts for an essential part (about 40%) of losses in a graphene nanoresonator and it is specific just for graphene. The ways of minimization of this kind of dissipation (an increase in the quality factor of the electromechanical system) are discussed. It is explained why one can enhance the quality factor by correctly choosing a combination of strains (by strain engineering). In addition, it is shown that the quality factor can be increased by switching on a magnetic field perpendicular to the graphene membrane.

Firsova, N. E.; Firsov, Yu A.

2012-10-01

355

Hot-solvent miscible displacement  

SciTech Connect

This work describes an experimental and theoretical investigation of miscible displacement under nonisothermal conditions. The hot miscible floods were performed in an adiabatic glass bead pack, displacing one hydrocarbon by a more viscous hydrocarbon, the latter being at an elevated temperature. As a result, dispersion of both mass and heat took place, and was determined by temperature and concentration measurements. The system was simulated by coupled convective-diffusion and thermal conduction-convection equations. The results of the numerical as well as an approximate analytical solution were compared with the experimentally observed behavior. The numerical and experimental results point to the factors which should be considered in the choice of a solvent for a thermal-miscible type oil recovery process.

Awang, M.; Farouq Ali, S.M.

1980-01-01

356

Knowledge integration and displaced volume  

NSDL National Science Digital Library

This study contrasted spontaneous and reflective knowledge integration instruction delivered using a computer learning environment to enhance understanding of displaced volume. Both forms of instruction provided animated experiments and required students to predict outcomes, observe results, and explain their ideas. In addition, the reflective instruction diagnosed specific inconsistencies in student reasoning and encouraged students to reflect on these dilemmas as well as to construct general principles. We distinguished the impact of instruction on students who believed scientific phenomena are governed by principles (cohesive beliefs) versus students who believed that science is a collection of unrelated ldquofactsrdquo (dissociated beliefs). Students typically held multiple models of displacement, using different explanations depending on the form of assessment. For example, we found that 17% of these middle school students made accurate predictions about displacement experiments prior to instruction and 25% could construct an accurate general principle. However, only 12% consistently used the same explanation across assessments. After instruction, students were more accurate and more consistent: over 50% accurately predicted experimental outcomes, 79% gave an accurate general principle, and about 40% gave consistent responses. We found no advantages for enhanced animations over straightforward animated experiments. The reflective integration instruction led to more substantial long-term changes in student understanding than did spontaneous integration instruction. Furthermore, on a delayed posttest we found that students with cohesive beliefs not only sustained their understanding of displaced volume, but, when exposed to reflective integration instruction, actually continued to construct more predictive views following instruction. In contrast, students with dissociated beliefs made no long-term progress independent of the form of instruction.

Linn, Marcia; Eylon, Bat-Sheva

2006-12-07

357

Refugees and Internally Displaced People  

Microsoft Academic Search

Millions of refugees and internally displaced people (IDP) reflect the human consequences of armed conflicts and disasters\\u000a around the world. These individuals, families, communities, and societies suffer from conditions of war and violence, all\\u000a of which can be considered human rights violations, including torture, rape, abductions, sexual violation, war wounds, deprivation\\u000a of basic needs, ethnic cleansing, persecution and harassment, loss

Nancy Baron; Soeren Buus Jensen; Joop T. V. M. Jong

358

Dynamic analysis for the Pouliot Variable Displacement Engine  

Microsoft Academic Search

The piston and the three connecting links in the Pouliot Variable Displacement Engine are dynamically analyzed. Given the cylinder pressure as a function of the crank angle, the internal member and bearing loads are determined, as well as the unbalanced forces due to the reciprocating masses. Friction forces which result in approximate power losses are included. The unbalanced forces are

Delameter

1975-01-01

359

Analog-to-digital conversion as a source of drifts in displacements derived from digital recordings of ground acceleration  

USGS Publications Warehouse

Displacements obtained from double integration of digitally recorded ground accelerations often show drifts much larger than those expected for the true ground displacements. These drifts might be due to many things, including dynamic elastic ground tilt, inelastic ground deformation, hysteresis in the instruments, and cross feed due to misalignment of nominally orthogonal sensors. This article shows that even if those effects were not present, the analog-to-digital conversion (ADC) process can produce apparent "pulses" and offsets in the acceleration baseline if the ground motion is slowly varying compared with the quantization level of the digitization. Such slowly varying signals can be produced by constant offsets that do not coincide with a quantization level and by near- and intermediate-field terms in the wave field radiated from earthquakes. Double integration of these apparent pulses and offsets leads to drifts in the displacements similar to those found in processing real recordings. These effects decrease in importance as the resolution of the ADC process increases.

Boore, D. M.

2003-01-01

360

The effect of elbow joint centre displacement on force generation and neural excitation  

Microsoft Academic Search

Joint centre displacement may occur following total elbow replacement due to aseptic loosening or surgical misalignment, and\\u000a has been linked to implant failure. In this study, the effects of joint centre displacement were examined using a neuromusculoskeletal\\u000a model of the elbow joint. Isometric contractions were simulated at a range of joint angles during elbow flexion and extension.\\u000a Displacement of the

Emer P. Doheny; Madeleine M. Lowery; Mark J. O’Malley; David P. FitzPatrick

2009-01-01

361

Competition and character displacement in two species of scincid lizards  

Microsoft Academic Search

The role of competition in habitat occupation and character displacement is investigated in two species of alpine lizards (Niveoscincus microlepidotus and N. greeni), using both controlled competition experiments and field-based ecological work. Competition experiments demonstrate that interspecific aggression occurs between these closely related species, with the larger and more aggressive N. greeni being socially dominant. When these species occur in

Jane Melville

2002-01-01

362

Economising plasma simulation by total neglect of the displacement current  

Microsoft Academic Search

Attention is called to the advantages of neglecting the displacement current in allowing larger space and time steps in numerical models, thereby extending their application. It is pointed out that this eliminates light waves and the Langmuir mode from the model; since the electric field must no longer be calculated from the charge density (because the quasi-neutral approximation has been

M. G. Brown; J. W. Dungey

1983-01-01

363

High Throughput Screening of Potential Displacer Molecules.  

National Technical Information Service (NTIS)

A bioproduct may be selectively separated from one or more impurities by means of a displacement chromatography system that includes a solvent, a chromatographic resin and a chemically selective displacer. The method includes: dissolving the bioproduct an...

S. M. Cramer K. Rege J. Dordick N. Tugcu

2005-01-01

364

The effect of location of a convective heat source on displacement ventilation: CFD study  

Microsoft Academic Search

Two-dimensional computational simulations are performed to examine the effect of vertical location of a convective heat source on thermal displacement ventilation systems. In this study, a heat source is modeled with seven different heights from the floor (0.5, 0.75, 1.0, 1.25, 1.5, 1.75, 2.0m) in a displacement ventilation environment. The flow and temperature fields in thermal displacement ventilation systems vary

Hee-Jin Park; Dale Holland

2001-01-01

365

Engineering of Schroedinger cat states by a sequence of displacements and photon additions or subtractions  

SciTech Connect

A method to generate Schroedinger cat states in free propagating optical fields based on the use of displaced states (or displacement operators) is developed. Some optical schemes with photon-added coherent states are studied. The schemes are modifications of the general method based on a sequence of displacements and photon additions or subtractions adjusted to generate Schroedinger cat states of a larger size. The effects of detection inefficiency are taken into account.

Podoshvedov, S. A., E-mail: podoshvedov@mail.ru [Seoul National University, Center for Subwavelength Optics and Department of Physics and Astronomy (Korea, Republic of)

2011-04-15

366

Emittance growth due to the wake field driven by an electron beam accelerated in an RF-gun of free electron laser ``ELSA''  

NASA Astrophysics Data System (ADS)

It appears that the ease of the parameter chosen for ``ELSA'' photo injector, the influence of the exit aperture, in terms of beam quality, is slight concerning the transverse emittance: (???/??)(z)~3% at maximum, and negligible concerning the axial emittance. To complete this paper, we recall the results previously obtained concerning the wake field of a closed or open cavity for a beam approaching the anode [6,7]. They had quantitatively specified the expected deep assymetry between the conducting walls regarding their contribution to the total wake field, besides the space-charge contribution. (Given that the radial walls have no time to contribute, these conducting walls are the cathode and the anode.) Thus, concerning the effects on whole-beam emittances, the correction (???/??)(z) entailed by taking the anode contribution into account had been found to be less than 5% at maximum (a maximum reached for t=tg, and for E0=30MV/m). The field map perturbation due to the aperture in the anode [7] has an effect of the same order of magnitude, i.e. small, on the transverse emittance of a beam reaching this exit aperture. As shown in Fig. /3, this correction is of order of 3% for E0=30MV/m. It could be of the order of 10% for E0=10MV/M.

Salah, W.; Dolique, J.-M.

2000-09-01

367

Ecological Character Displacement in Adaptive Radiation  

Microsoft Academic Search

I give an overview of the observational and experimental evidence for ecological character displacement in adaptive radiation. Sixty-one published cases of character displacement involving closely related species (congeners) make up the observational data set. All cases involve divergence, even though parallel and convergent dis- placement are theoretically possible. Character ratios in sympatry were greatest when displacement was symmetric (mean 1.54)

Dolph Schluter

2000-01-01

368

Atrioventricular plane displacement in female endurance athletes  

Microsoft Academic Search

WISLØFF, U., J. HELGERUD, A. STØYLEN, and Ø. ELLINGSEN. Atrioventricular plane displacement in female endurance athletes. Med. Sci. Sports Exerc., Vol. 33, No. 9, 2001, pp. 1503-1510. Introduction: A novel hypothesis for increased ventricular pumping describes the heart as a displacement pump, in which atrioventricular plane displacement (AVPD) is an important mechanism. The hypothesis predicts that AVPD increases at high

ULRIK WISLØFF; JAN HELGERUD; ASBJØRN STØYLEN; ØYVIND ELLINGSEN

369

Burglary Reduction and the Myth of Displacement  

Microsoft Academic Search

Burglary remains a significant crime problem across Australia. While the Australian Institute of Criminology is keen to encourage burglary reduction initiatives, it often encounters the view that targeted operations simply displace crime to another area. This perception of total crime displacement is common, but has no strong evidential basis. While some studies have measured a modest degree of displacement in

Jerry Ratcliffe

2002-01-01

370

Lattice viscosity of displacive ferroelectric crystals  

NASA Astrophysics Data System (ADS)

With the aid of the double-time thermal Green's-function method and the correlation function formula, the lattice viscosity of a displacive-type ferroelectric crystal in the paraelectric phase is theoretically investigated from a modification of the Silverman and Joseph Hamiltonian considering dominant third- and fourth-order anharmonic terms in the lattice potential energy. It is shown that the total viscosity can be separated into two terms arising from acoustical and optical phonons, which for a small half-width of phonons reduce to the form similar to that propounded by Rice. The temperature dependence of the viscosity is discussed. In the vicinity of the Curie temperature, the viscosity shows an anomalous temperature behavior due to a soft mode, in agreement with experimental investigations.

Goyal, V. K.; Sharma, P. K.

1981-02-01

371

Current Density and Plasma Displacement Near Perturbed Rational Surface  

SciTech Connect

The current density in the vicinity of a rational surface of a force-free magnetic field subjected to an ideal perturbation is shown to be the sum of both a smooth and a delta-function distribution, which give comparable currents. The maximum perturbation to the smooth current density is comparable to a typical equilibrium current density and the width of the layer in which the current flows is shown to be proportional to the perturbation amplitude. In the standard linearized theory, the plasma displacement has an unphysical jump across the rational surface, but the full theory gives a continuous displacement.

A.H. Boozer and N. Pomphrey

2010-10-10

372

An Alternative Introduction to Maxwell's Displacement Current  

NASA Astrophysics Data System (ADS)

In introductory texts Ampere's law is generally introduced in the steady-current form ? B .dl = ?0 I, and it is later extended to a more general form1,2,3,4 involving the socalled displacement current Id, ? B .dl=?0 (I+Id). Here the line integral is to be taken along a closed Amperian loop, and I is the net conventional current that penetrates any surface bounded by the loop. In its steady-current form (without Id), Ampere's law is used to find the magnetic field generated by highly symmetric arrangements of current-carrying wires, for example, an infinite straight line of current or an infinite solenoid, in analogy with Gauss's law.

Reich, Gary

2013-11-01

373

Miscible displacement by high-pressure gas at Block 31  

Microsoft Academic Search

The world's first large-scale miscible displacement project by high-pressure gas injection has produced 130,000,000 bbl, almost double the original estimated primary recovery of 69,000,000 bbl, at the University Block 31 field in Crane County, Texas. The field-wide project began in 1952, and will keep the unit on stream well into the future, with ultimate recovery efficiency estimated at 60%. Infill

J. H. Hardy; N. Robertson

1975-01-01

374

Three-input majority logic gate and multiple input logic circuit based on DNA strand displacement.  

PubMed

In biomolecular programming, the properties of biomolecules such as proteins and nucleic acids are harnessed for computational purposes. The field has gained considerable attention due to the possibility of exploiting the massive parallelism that is inherent in natural systems to solve computational problems. DNA has already been used to build complex molecular circuits, where the basic building blocks are logic gates that produce single outputs from one or more logical inputs. We designed and experimentally realized a three-input majority gate based on DNA strand displacement. One of the key features of a three-input majority gate is that the three inputs have equal priority, and the output will be true if any of the two inputs are true. Our design consists of a central, circular DNA strand with three unique domains between which are identical joint sequences. Before inputs are introduced to the system, each domain and half of each joint is protected by one complementary ssDNA that displays a toehold for subsequent displacement by the corresponding input. With this design the relationship between any two domains is analogous to the relationship between inputs in a majority gate. Displacing two or more of the protection strands will expose at least one complete joint and return a true output; displacing none or only one of the protection strands will not expose a complete joint and will return a false output. Further, we designed and realized a complex five-input logic gate based on the majority gate described here. By controlling two of the five inputs the complex gate can realize every combination of OR and AND gates of the other three inputs. PMID:23710909

Li, Wei; Yang, Yang; Yan, Hao; Liu, Yan

2013-05-30

375

Carbon nanotube-coated electroactive paper (EAPap) as hybrid high-displacement actuator  

NASA Astrophysics Data System (ADS)

Electro-Active Paper (EAPap) has been investigated as an attractive EAP material for artificial muscles due to its many advantages such as lightweight, availability, low cost, large displacement output, low actuation voltage and low power consumption. The EAPap is based on cellulose material, and is shown to involve primarily transport of ions in response to an external electric field. Depending on the electrode material, EAPap has shown actuation displacement in the range of 2-4mm, at a few volts. Drawbacks of EAPap actuators include a low force output and a dependence on humidity. To address these limitations, a hybrid EAPap actuator is developed by incorporating an electrode fabricated using single-wall carbon nanotubes (SWNT)/Polyaniline (PANI) with different dopants. SWNT is dispersed in 1-Methy-2-pyrrolidone (NMP), and the resulting solution is used as a solvent for PANI and the various dopants. The SWNT/PANI/NMP solution is then deposited on the EAPap by spin coating. The coated EAPap is dried in a vacuum oven. Raman spectroscopy, X-Ray diffractometry and SEM tests are taken to confirm that the SWNT/PANI/dopant electrode material is successfully prepared by in situ polymerization. The actuation output of the SWNT/PANI/EAPap samples is tested in an environmental chamber in terms of free displacement and blocked force. When the SWNT/PANI/Cl- coated hybrid actuator is excited with 7Vp-p, a maximum displacement of 3.1mm and a maximum power output of 0.29mW are obtained. The hybrid actuator shows an improved actuation force as a result of enhanced stiffness of EAPap.

Yun, Sungryul; Kim, Jaehwan; Ounaies, Zoubeida; St Clair, T.

2005-05-01

376

Inductive Displacement Sensor for Force Measuring in Humanoid Robotic Application: Testing the Invariance on Angular Displacement  

Microsoft Academic Search

A planar displacement inductive sensor, usable in robotics, is presented in the paper. The sensor is composed of two sensor elements. The first sensor element detects vertical displacement while the second sensor element detects horizontal displacement. Combining information from these two sensor elements, it is possible to determine displacement in a plane. Sensor element is a pair of meander coils.

Snezana M. Djuric; Laszlo Nagy; Mirjana Damnjanovic

2009-01-01

377

Civil Conflict and Forced Migration: The Micro Determinants and Welfare Losses of Displacement in Colombia  

Microsoft Academic Search

Summary Forced displacement in Colombia has soared due to the escalating internal conflict. The purpose of this paper is twofold: first, to identify adequate instruments for addressing the problem of displacement by estimating its determinants and comparing these findings with the standard migration literature; second, to estimate its welfare losses, thus providing evidence as to whether the response to this

Carlos Eduardo Vélez

2008-01-01

378

Simultaneous detection of translational and angular displacements of micromachined elements  

SciTech Connect

An astigmatic detection system is constructed with a modified digital-versatile-disk optical head. This system, with a detecting spot of {approx}1 {mu}m, can simultaneously measure the vertical displacements and two-dimensional angular tilts of micromachined elements. It can detect thermal vibrations of microfabricated cantilevers with noise levels of 1.3 pm Hz{sup -1/2} for the linear displacement and of 3.2 nrad Hz{sup -1/2} for angular displacements over a frequency range from 1 to 800 kHz. The detecting frequency can even reach beyond 100 MHz if high-speed electronic devices are adopted. Further optimization of the system will broaden its applications in diverse technological fields.

Hwu, E.-T.; Hung, S.-K.; Yang, C.-W.; Hwang, I.-S.; Huang, K.-Y. [Institute of Physics, Academia Sinica, Nankang, Taipei, Taiwan (China); Department of Mechanical Engineering, National Taiwan University, Taipei, Taiwan (China)

2007-11-26

379

Picometer level displacement metrology with digitally enhanced heterodyne interferometry.  

PubMed

Digitally enhanced heterodyne interferometry is a laser metrology technique employing pseudo-random codes phase modulated onto an optical carrier. We present the first characterization of the technique's displacement sensitivity. The displacement of an optical cavity was measured using digitally enhanced heterodyne interferometry and compared to a simultaneous readout based on conventional Pound-Drever-Hall locking. The techniques agreed to within 5 pm/ radicalHz at 1 Hz, providing an upper bound to the displacement noise of digitally enhanced heterodyne interferometry. These measurements employed a real-time signal extraction system implemented on a field programmable gate array, suitable for closed-loop control applications. We discuss the applicability of digitally enhanced heterodyne interferometry for lock acquisition of advanced gravitational wave detectors. PMID:19158897

de Vine, Glenn; Rabeling, David S; Slagmolen, Bram J J; Lam, Timothy T-Y; Chua, Sheon; Wuchenich, Danielle M; McClelland, David E; Shaddock, Daniel A

2009-01-19

380

Displacement and adolescent suicide: introduction to a special section.  

PubMed

Empirical findings from previous studies indicate that the risk factors for adolescent suicide are multifaceted and likely the result of the interaction between individual and contextual risk factors. In this special section, we focus on one subdomain of risk factors for adolescent suicide, namely, displacement. During adolescence, experiences of displacement due to changes in family or peer relationships may be particularly important because these relationships play a key role in meeting developmental tasks. This special section brings together new findings from four empirical studies investigating how displacement affects risk for suicide across individuals in different contexts and across various domains of displacement. The findings suggest that (a) these risk factors are multifaceted and (b) they often represent an interaction between individual and contextual risk factors. At the same time, the articles in this special section indicate that the role of displacement is complex, and it may sometimes serve a protective role when combined with other factors (e.g., mental health treatment). PMID:22023269

van Dulmen, Manfred H M; Bossarte, Robert M; Swahn, Monica H

2011-01-01

381

Tsunami mortality and displacement in Aceh province, Indonesia.  

PubMed

A survey of 388 Indonesian households displaced by the December 2004 tsunami was conducted in Aceh province in February 2005. Of tsunami-displaced households in Aceh Barat and Nagan Raya districts, 61.8 per cent reported one or more family members as dead or missing due to the tsunami, with an overall mortality rate of 13.9 per cent (95% confidence interval (CI): 12.4-15.4). Risk of death was greatest in the youngest and oldest age groups, and among females. Overall, 36 per cent of tsunami-displaced households indicated an intention to return to their original community within three months, and displaced households residing in host communities were 2.2 (95% CI: 1.2-2.8) times more likely to state an intention to return to their original villages or another community as those residing in camps. The tsunami recovery effort should focus on strategies that facilitate either prompt return or permanent, voluntary relocation for those displaced. PMID:16911432

Rofi, Abdur; Doocy, Shannon; Robinson, Courtland

2006-09-01

382

SMA-based smart damper/displacement transducer  

NASA Astrophysics Data System (ADS)

An innovative smart shape memory alloy (SMA) -based damper/displacement transducer, which had comprehensive energy dissipation and strain self-sensing abilities (i.e. electric resistance vs. applied strain relationship) simultaneously, was proposed in this paper. This smart SMA-based damper/displacement transducer had three characteristics: 1) SMA wires in the damper/transducer were always elongated during the entire excitation; 2) SMA wires dissipated energy with re-centering ability due to pseudoelasticity; 3) SMA damper/transducer could simultaneously play the role of displacement transducer due to the strain self-sensing property of SMA wires in the damper. Such smart SMA-based damper/displacement transducer, incorporated into a building or a bridge, provided the potential to rapidly assess post-earthquake safety of structures. A large number of tests were conducted firstly, on the hysteresis stress-strain-electric resistance relationship of NiTi SMA wires (diameter 1.2mm). These tests were carried out under sinusoidal excitations with different loading frequencies at room temperature. The experimental results indicated that the pseudoelastic hysteresis loops of the SMA wires were dependent on loading frequency. In addition, the sensitivity coefficient of electric resistance vs. applied strain of the NiTi wires was identified to be 6.466 from the test results, which was independent of the loading frequency. Finally, shake table tests for a scaled 5-story steel frame, with the said smart SMA dampers/displacement transducers at the first story, subjected to various earthquake excitations, were conducted. The results of the shake table tests indicated that not only could the smart SMA damper/displacement transducers suppress structural seismic response effectively, but also it could monitor structural interstory drifts accurately.

Mao, Chen-xi; Li, Hui

2005-05-01

383

An Inexpensive Interferometric Setup for Measuring Microscopic Displacements  

NASA Astrophysics Data System (ADS)

In an interesting article published in an issue of The Physics Teacher, Reichert1 gives some didactic examples about static friction force between a plastic block and a wooden plane on which it rests. To explain the experiments, he uses a simple model based on a microscopic ``elastic band'' that connects the atoms of both surfaces. Reichert remarks that ``the block moves, albeit a microscopic distance,'' and that it would be helpful if the student could see these displacements. In another paragraph he states that ``measuring it (displacement) requires delicate and expensive optical instruments.'' Effectively, a measurement of such small displacements generally requires interferometric devices. At our university, we teach basic physics and we are aware of the difficulties that beginners have grasping the concepts involved in static friction force. At the same time, as our research field is related to optics metrology, we could not ignore Reichert's statement. Could we design an experimental device to measure the microscopic displacement referred to by Reichert, keeping it inexpensive and easy to implement? Incidentally, in the same issue of The Physics Teacher, Sawicki2 gives an excellent example of how, with a few common elements, a simple experiment of interferometric measurement can be put within students' reach. In this paper, we suggest the use of a simple interferometric device, built with very common and inexpensive elements, and describe an experiment on static friction force in which the instrument is applied to measure microscopic displacements.

Alanís, Elvio; Romero, Graciela; Martínez, Carlos; Álvarez, Liliana; Salazar, Germán

2004-04-01

384

Displaced Women in Northern GhanaIndigenous Knowledge About Ethnic Conflict  

Microsoft Academic Search

This article presents the findings of field research in Ghana in 2002 about internal displacement stemming from multiethnic violence in northern Ghana in 1994, known as the “Guinea Fowl War.” Indigenous, gender-specific knowledge from displaced Ghanaian women is presented in the context of feminist perspectives on the consequences of regional wars on non-combatants. The research generated indigenous material for social

Brenda Faye McGadney-Douglass; William K. Ahadzie

2008-01-01

385

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

PubMed

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

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

2011-12-28

386

An accurate elasto-plastic frictional tangential force displacement model for granular-flow simulations: Displacement-driven formulation  

NASA Astrophysics Data System (ADS)

We present in this paper the displacement-driven version of a tangential force displacement (TFD) model that accounts for both elastic and plastic deformations together with interfacial friction occurring in collisions of spherical particles. This elasto-plastic frictional TFD model, with its force-driven version presented in [L. Vu-Quoc, L. Lesburg, X. Zhang. An accurate tangential force displacement model for granular-flow simulations: contacting spheres with plastic deformation, force-driven formulation, Journal of Computational Physics 196(1) (2004) 298 326], is consistent with the elasto-plastic frictional normal force displacement (NFD) model presented in [L. Vu-Quoc, X. Zhang. An elasto-plastic contact force displacement model in the normal direction: displacement-driven version, Proceedings of the Royal Society of London, Series A 455 (1991) 4013 4044]. Both the NFD model and the present TFD model are based on the concept of additive decomposition of the radius of contact area into an elastic part and a plastic part. The effect of permanent indentation after impact is represented by a correction to the radius of curvature. The effect of material softening due to plastic flow is represented by a correction to the elastic moduli. The proposed TFD model is accurate, and is validated against nonlinear finite element analyses involving plastic flows in both the loading and unloading conditions. The proposed consistent displacement-driven, elasto-plastic NFD and TFD models are designed for implementation in computer codes using the discrete-element method (DEM) for granular-flow simulations. The model is shown to be accurate and is validated against nonlinear elasto-plastic finite-element analysis.

Zhang, Xiang; Vu-Quoc, Loc

2007-07-01

387

Design and analysis of displacement measurement system based on the four-quadrant detector  

NASA Astrophysics Data System (ADS)

The four-quadrant detector is mainly used in high-precision displacement measurement and other related fields. With the emergence of displacement problem in a large number of projects, the displacement measurement accuracy, speed and reliability have become increasingly demanding. In this paper, the measurement principle of four-quadrant detector is analyzed theoretically, the displacement measurement system based on four-quadrant detector is designed, and the experimental platform is built to test and validate the stability, measurement accuracy and range of the displacement measurement system. Experimental results show that: the deviation of the same spot position on measurement system is less than 0.17?m. The measurement error of spot displacement is less than 3.7?m.

Gao, Zi-jun; Dong, Li-li; Xu, Wen-hai

2013-09-01

388

Variable delivery, fixed displacement pump  

DOEpatents

A variable delivery, fixed displacement pump comprises a plurality of pistons reciprocated within corresponding cylinders in a cylinder block. The pistons are reciprocated by rotation of a fixed angle swash plate connected to the pistons. The pistons and cylinders cooperate to define a plurality of fluid compression chambers each have a delivery outlet. A vent port is provided from each fluid compression chamber to vent fluid therefrom during at least a portion of the reciprocal stroke of the piston. Each piston and cylinder combination cooperates to close the associated vent port during another portion of the reciprocal stroke so that fluid is then pumped through the associated delivery outlet. The delivery rate of the pump is varied by adjusting the axial position of the swash plate relative to the cylinder block, which varies the duration of the piston stroke during which the vent port is closed.

Sommars, Mark F. (Sparland, IL)

2001-01-01

389

Displacement Based Seismic Design Criteria  

SciTech Connect

The USNRC has initiated a project to determine if any of the likely revisions to traditional earthquake engineering practice are relevant to seismic design of the specialized structures, systems and components of nuclear power plants and of such significance to suggest that a change in design practice might be warranted. As part of the initial phase of this study, a literature survey was conducted on the recent changes in seismic design codes/standards, on-going activities of code-writing organizations/communities, and published documents on displacement-based design methods. This paper provides a summary of recent changes in building codes and on-going activities for future codes. It also discusses some technical issues for further consideration.

Costello, J.F.; Hofmayer, C.; Park, Y.J.

1999-03-29

390

DISPLACEMENT BASED SEISMIC DESIGN CRITERIA  

SciTech Connect

The USNRC has initiated a project to determine if any of the likely revisions to traditional earthquake engineering practice are relevant to seismic design of the specialized structures, systems and components of nuclear power plants and of such significance to suggest that a change in design practice might be warranted. As part of the initial phase of this study, a literature survey was conducted on the recent changes in seismic design codes/standards, on-going activities of code-writing organizations/communities, and published documents on displacement-based design methods. This paper provides a summary of recent changes in building codes and on-going activities for future codes. It also discusses some technical issues for further consideration.

HOFMAYER,C.H.

1999-03-29

391

Influence of lateral displacement on the levitation performance of a magnetized bulk high-Tc superconductor magnet  

NASA Astrophysics Data System (ADS)

Compared with the permanent magnet, the magnetized bulk high-Tc superconductor magnet (MBSCM) can trap higher magnetic field due to its strong flux pinning ability, so it is a good candidate to improve the levitation performance of high-Tc superconductive (HTS) maglev system. The trapped magnetic flux of a MBSCM is sustained by the inductive superconducting current produced by the magnetizing process and is susceptible to the current intensity as well as configuration. In the HTS maglev system, the lateral displacement is an important process to change the superconducting current within a MBSCM and then affects its levitation performance, which is essential for the traffic ability in curve-way, the loading capacity of lateral impact and so on. The research about influence of lateral displacement on the levitation performance of MBSCM is necessary when MBSCM is applied on the HTS maglev vehicle. The experimental investigations about the influence of lateral displacement on the levitation performance of a MBSCM with different trapped fluxes and applied fields are processed in this article. The analyses and conclusions of this article are useful for the practical application of MBSCM in HTS maglev system.

Liu, W.; Wang, J. S.; Ma, G. T.; Zheng, J.; Tuo, X. G.; Li, L. L.; Ye, C. Q.; Liao, X. L.; Wang, S. Y.

2012-03-01

392

40 CFR 86.419-2006 - Engine displacement, motorcycle classes.  

Code of Federal Regulations, 2011 CFR

...false Engine displacement, motorcycle classes. 86.419-2006 Section 86.419-2006...419-2006 Engine displacement, motorcycle classes. (a)(1) Engine displacement...b) Motorcycles will be divided into classes based on engine displacement....

2011-07-01

393

Length-displacement scaling relations and the development of faults  

NASA Astrophysics Data System (ADS)

Faults are complex systems whose growth and general evolution are still not well understood. Such an understanding, however, is important for several reasons: one is that seismogenic faults generate earthquakes and another is that faults are major conduits for fluids (groundwater, geothermal water, gas, oil, magma). It is widely accepted that faults normally initiate from 'flaws' or weaknesses in the rocks, but their subsequent development and growth and their seismogenic activity are less well understood. Here we present results on the slip/displacement-length scaling relations, both for faults and co-seismic ruptures, from a single comparatively small area, namely the eastern flank of the volcano Etna, Italy (Sicily). Using these data, together with data from the literature and analytical and numerical models, we provide a general growth model for faults. Following an earthquake in a fault zone, the co-seismic rupture length and the slip are commonly measured. Similarly, in a structural analysis of major faults, the total fault length and displacement are measured when possible. It is well known that typical rupture length - slip ratios are generally orders of magnitude larger than typical fault length-displacement ratios. So far, however, most of the measured co-seismic ruptures and faults have been from different areas and commonly hosted by rocks of widely different mechanical properties (which have strong effects on these ratios). The data presented here is composed of length-displacement ratios from 7 fault zones in Holocene lava flows on the flanks of the volcano Etna and 19 co-seismic rupture lengths-slips mostly from the same fault zones and thus hosted by rocks with largely the same mechanical properties. For the co-seismic ruptures, the average length is 3,657 m, the average slip 0.31 m, and the average length-slip ratio 19,595. For the faults, the average length is 6,341 m, the average displacement 73 m, and the average length-displacement ratio 130. Thus, the average rupture-slip ratio is about 150-times larger than the length-displacement ratio. We propose that the differences between the length-slip and the length-displacement ratios can be partly explained by dynamic Young's modulus of fault zone being 101-2-times greater than its static modulus. In this model, the dynamic modulus controls the length-slip ratios whereas the static modulus controls the length-displacement ratio. We suggest that the common aseismic slip in fault zones is partly due to adjustment of the short-term seismogenic length-slip ratios to the long-term length-displacement ratios. Fault displacement is here regarded as analogous to plastic flow, in which case the long-term displacement can be very large so long as sufficient shear stress concentrates in the fault. In conclusion, this model explains, partly at least, the difference in the slip/displacement-length scaling relations between co-seismic ruptures and faults and also explains slow earthquakes and aseismic slip, features that are now known to be very common in active fault zones.

Gudmundsson, Agust; De Guidi, Giorgio; Scudero, Salvatore

2013-04-01

394

Study of microdosimetric energy deposition patterns in tissue-equivalent medium due to low-energy neutron fields using a graphite-walled proportional counter.  

PubMed

To improve radiation protection dosimetry for low-energy neutron fields encountered in nuclear power reactor environments, there is increasing interest in modeling neutron energy deposition in metrological instruments such as tissue-equivalent proportional counters (TEPCs). Along with these computational developments, there is also a need for experimental data with which to benchmark and test the results obtained from the modeling methods developed. The experimental work described in this paper is a study of the energy deposition in tissue-equivalent (TE) medium using an in-house built graphite-walled proportional counter (GPC) filled with TE gas. The GPC is a simple model of a standard TEPC because the response of the counter at these energies is almost entirely due to the neutron interactions in the sensitive volume of the counter. Energy deposition in tissue spheres of diameter 1, 2, 4 and 8 µm was measured in low-energy neutron fields below 500 keV. We have observed a continuously increasing trend in microdosimetric averages with an increase in neutron energy. The values of these averages decrease as we increase the simulated diameter at a given neutron energy. A similar trend for these microdosimetric averages has been observed for standard TEPCs and the Rossi-type, TE, spherical wall-less counter filled with propane-based TE gas in the same energy range. This implies that at the microdosimetric level, in the neutron energy range we employed in this study, the pattern of average energy deposited by starter and insider proton recoil events in the gas is similar to those generated cumulatively by crosser and stopper events originating from the counter wall plus starter and insider recoil events originating in the sensitive volume of a TEPC. PMID:21476858

Waker, A J; Aslam

2011-04-08

395

Internal displacement and health among the Palestinian minority in Israel.  

PubMed

Long term health impacts of internal displacement (ID) resulting from political violence are not well documented or understood. One such case is the ID of 300,000-420,000 Palestinian citizens of Israel and their descendants during the Nakba of 1948 (Palestinian Catastrophe). We aim to document the long term health impacts of this ID. We draw on data collected in 2005 from a nationwide random sample of 902 individuals aged 30-70. Research participants were interviewed in person after being selected through a multistage sampling procedure. About 24% of participants reported that either they or their families had been internally displaced. Palestinian internally displaced persons (IDPs), that is, those who were forcibly displaced and dispossessed from their homes and lands during the Nakba and its aftermath, as well as their families and descendants, and who reside within the current borders of Israel, had an odds ratio of 1.45 (95% CI = 1.02-2.07) for poor self-rated health (SRH) compared to non-IDPs after controlling for demographic, socioeconomic and psychosocial factors. No difference was found between IDPs and non-IDPs in limiting longstanding illness following control for confounders. Low socioeconomic position and chronic stress were significantly related to ID and to SRH. Our findings suggest adverse long term health impacts of the Nakba on the IDPs when compared to non-IDPs. We propose that these disparities might stem from IDPs' unhealed post-traumatic scars from the Nakba, or from becoming a marginalized minority within their own society due to their displacement and loss of collective identity. Given these long term health consequences, we conclude that displacement should be addressed with health and social policies for IDPs. PMID:22386615

Daoud, Nihaya; Shankardass, Ketan; O'Campo, Patricia; Anderson, Kim; Agbaria, Ayman K

2012-02-11

396

Assessing the displacement effects of the Internet  

Microsoft Academic Search

This study examines the ''medium-centric'' and ''user-centric'' approaches in investigating the displacement effects of the Internet. Results from a random sample survey support the ''medium-centric'' approach in displacement effect. The use of the Internet does displace traditional media use of television, newspapers, and radio. The Internet performs a sub- stitutive rather than supplementary function. More important, the use of absolute

Paul S. N. Lee; Louis Leung

2008-01-01

397

Transverse sacral fractures with anterior displacement  

Microsoft Academic Search

Transverse fractures of the sacrum with anterior displacement are the rarest type of transverse sacral fractures. They usually\\u000a occur at the S1–S2 region in suicide jumpers. A clinical study was performed to evaluate the diagnosis, treatment and outcome\\u000a of transverse sacral fractures with anterior displacement. We present six patients with a transverse fracture of the sacrum\\u000a with anterior displacement. All

George S. Sapkas; Andreas F. Mavrogenis; Panayiotis J. Papagelopoulos

2008-01-01

398

Microbial Adhesion in Flow Displacement Systems  

PubMed Central

Flow displacement systems are superior to many other (static) systems for studying microbial adhesion to surfaces because mass transport and prevailing shear conditions can be adequately controlled and notoriously ill-defined slight rinsing steps to remove so-called “loosely adhering organisms” can be avoided. In this review, we present the basic background required to calculate mass transport and shear rates in flow displacement systems, focusing on the parallel plate flow chamber as an example. Critical features in the design of flow displacement systems are discussed, as well as different strategies for data analysis. Finally, selected examples of working with flow displacement systems are given for diverse biomedical applications.

Busscher, Henk J.; van der Mei, Henny C.

2006-01-01

399

Study on the time-grating displacement sensor of mix-motivating type  

Microsoft Academic Search

In this paper a new novel time-grating displacement sensor of mix-motivating type with the mechanism movement and the traveling wave magnetic field is proposed for the first time. In the research of time-grating displacement sensor, the mechanism-motivating modulation sensor are compared with the electricity-motivating modulation sensor rom various fields. It is found that, on the one hand, the two set

Donglin Peng; Xinghong Zhang; Xiaokang Liu; Wei Yang

2005-01-01

400

Displacement current in bottom-contact organic thin-film transistor  

NASA Astrophysics Data System (ADS)

We have used the Shockley-Ramo theorem to calculate the displacement current of drifting charge carriers in bottom-contact organic thin-film transistors (OTFTs). The displacement current is quantified in terms of the weighting field of the sensing electrode. We demonstrated that for the transistors, with dielectric thickness below 100 nm and channel length above 1 µm, the weighting field near the sensing electrode exponentially decays with the distance from the electrode. This implies that the charge transport near metal contacts can be studied with a measurement of displacement current. The presented model approximation simplifies interpretation of, for example, transient photocurrent measurements and optical de-trapping measurements in OTFTs.

Pavlica, E.; Bratina, G.

2008-07-01

401

Improved Wide Range Expressions for Displacements and Inverse Displacements for Standard Fracture Toughness Specimens.  

National Technical Information Service (NTIS)

Wide range expressions (interpolating polynomials) for displacements for standard ASTM fracture testing specimens have been developed. The strategy for fitting was to fit displacements as a function of crack length for all of the specimens using a similar...

J. A. Kapp

1992-01-01

402

Displacement current phenomena in the magnetically insulated transmission lines of the refurbished Z accelerator  

NASA Astrophysics Data System (ADS)

Experimental data is presented that illustrates important displacement current phenomena in the magnetically insulated transmission lines (MITLs) of the refurbished Z accelerator [D. V. Rose , Phys. Rev. ST Accel. Beams 13, 010402 (2010)PRABFM1098-440210.1103/PhysRevSTAB.13.010402]. Specifically, we show how displacement current in the MITLs causes significant differences between the accelerator current measured at the vacuum-insulator stack (at a radial position of about 1.6 m from the Z axis of symmetry) and the accelerator current measured at the load (at a radial position of about 6 cm from the Z axis of symmetry). The importance of accounting for these differences was first emphasized by Jennings et al. [C. A. Jennings , IEEE Trans. Plasma Sci. 38, 529 (2010)ITPSBD0093-381310.1109/TPS.2010.2042971], who calculated them using a full transmission-line-equivalent model of the four-level MITL system. However, in the data presented by Jennings et al., many of the interesting displacement current phenomena were obscured by parasitic current losses that occurred between the vacuum-insulator stack and the load (e.g., electron flow across the anode-cathode gap). By contrast, the data presented herein contain very little parasitic current loss, and thus for these low-loss experiments we are able to demonstrate that the differences between the current measured at the stack and the current measured at the load are due primarily to the displacement current that results from the shunt capacitance of the MITLs (about 8.41 nF total). Demonstrating this is important because displacement current is an energy storage mechanism, where energy is stored in the MITL electric fields and can later be used by the system. Thus, even for higher-loss experiments, the differences between the current measured at the stack and the current measured at the load are often largely due to energy storage and subsequent release, as opposed to being due solely to some combination of measurement error and current loss in the MITLs and/or double post-hole convolute. Displacement current also explains why the current measured downstream of the MITLs (i.e., the load current) often exceeds the current measured upstream of the MITLs (i.e., the stack current) at various times in the power pulse (this particular phenomenon was initially thought to be due to timing and/or calibration errors). To facilitate a better understanding of these phenomena, we also introduce and analyze a simple LC circuit model of the MITLs. This model is easily implemented as a simple drive circuit in simulation codes, which has now been done for the LASNEX code [G. B. Zimmerman and W. L. Kruer, Comments Plasma Phys. Controlled Fusion 2, 51 (1975)CPCFBJ0374-2806] at Sandia, as well as for simpler MATLAB®-based codes at Sandia. An example of this LC model used as a drive circuit will also be presented.

McBride, R. D.; Jennings, C. A.; Vesey, R. A.; Rochau, G. A.; Savage, M. E.; Stygar, W. A.; Cuneo, M. E.; Sinars, D. B.; Jones, M.; Lechien, K. R.; Lopez, M. R.; Moore, J. K.; Struve, K. W.; Wagoner, T. C.; Waisman, E. M.

2010-12-01

403

Drilling with new-generation positive displacement motors  

SciTech Connect

The paper describes a new generation of positive displacement downhole mud motors designed for long interval straight hole drilling with natural or man-made diamonds bits or with conventional three-cone rock bits. Field results have demonstrated that these motors are now cost-competitive with rotary drilling methods. The advantages of increased penetration, deviation control and reduced casing wear contribute to a lower cost per foot of hole drilled compared to rotary techniques. 3 refs.

Herbert, P.

1981-01-01

404

Displacement power spectrum measurement by CPMG in constant gradient  

Microsoft Academic Search

The modulation of spin phase produced by Carr-Purcell-Meiboom-Gill (CPMG) sequence in combination with constant magnetic field gradient is appropriate to probe the displacement power spectrum (DPS). The spin-echo attenuation is directly proportional to the DPS value at the applied modulation frequency. Relaxation and selective excitation effects can be factored out while probing the DPS. The modulation frequency is adjusted by

Samo Lasica; Janez Stepisnik

405

Displacement power spectrum measurement by CPMG in constant gradient  

Microsoft Academic Search

The modulation of spin phase produced by Carr–Purcell–Meiboom–Gill (CPMG) sequence in combination with constant magnetic field gradient is appropriate to probe the displacement power spectrum (DPS). The spin-echo attenuation is directly proportional to the DPS value at the applied modulation frequency. Relaxation and selective excitation effects can be factored out while probing the DPS. The modulation frequency is adjusted by

Samo Lasic; Janez Stepisnik; Aleš Mohori?

2006-01-01

406

Local Time Displacement of Substorm Expansion in Conjugate Hemispheres  

NASA Astrophysics Data System (ADS)

Because the Earth's magnetic field is largely dipolar and symmetric, many auroral features are conjugate between the northern and southern hemispheres. However, previous work has shown that the aurora can be nonconjugate. Most previous optical conjugacy studies have been limited to ground based observations or ground based and space based imager comparisons. In both cases at least one observation point is restricted to viewing only small scale features. Conjugate observations of the large scale behavior of the aurora have been confined to rare, serendipitous space based imager conjunctions and single spacecraft viewing of both hemispheres which is tempered by large oblique viewing angles. As the Polar spacecraft's apogee has descended in the the southern hemisphere, the Polar Ultraviolet Imager (UVI) has spent an increasing amount of time viewing the southern aurora. Simultaneously, the Wideband Imaging Camera (WIC) onboard the IMAGE spacecraft has been observing the northern aurora. By using image data from both spacecraft, we are able to systematically analyze the degree of auroral conjugacy on synoptic scales and over a wide variety of geomagnetic conditions. In this work, we focus on the conjugacy of the region of intense auroral emission during substorm onset and expansion. We find a persistent displacement in local time of the region of active aurora during substorm expansion; features in the northern hemisphere are shifted westward (duskward) relative to the conjugate point of the southern hemisphere aurora by up to a few thousand kilometers. Often there is a shift in the opposite direction observed before and at substorm onset. The same sense of displacement has been reported in earlier work. The sense or magnitude of the displacement showns no obvious correlation with the interplanetary magnetic field orientation or strength as suggested in previous studies. Therefore, we suggest that the displacement in local time of the region of intense auroral emission is a result of the asymmetric distortion of the magnetic field by the large scale field-aligned currents associated with substorms.

Fillingim, M. O.; Tung, Y.; Parks, G. K.; Mende, S. B.; Frey, H. U.; Immel, T. J.

2003-12-01

407

Perceptual adaptation to inverted, reversed, and displaced vision  

Microsoft Academic Search

Recent research has shown that a simple form of adaptation to prism-produced displacement of the visual field consists primarily of a proprioceptive change––a change in the felt position of the arm seen through prisms––rather than a visual, motor, or visuomotor change. More complex sorts of adaptation (to inversion, reversal, and other optical transformations) can also be understood as resulting from

Charles S. Harris

1965-01-01

408

Roughness length and displacement height derived from building databases  

SciTech Connect

In air quality and meteorological models, the bulk drag and turbulence enhancement due to cities is often parameterized through the roughness length (z{sub 0}) and displacement height (d). These log-law parameters have traditionally been derived from meteorological measurements and building morphological characteristics (e.g., see Grimmond and Oke, 1999). We are in the midst of an effort to characterize the morphological properties of some of the major cities in the western U.S. At this time we have completed the analyses for Los Angeles, Phoenix, and Salt Lake City. We are currently working with datasets from Portland and Houston and anticipate analyzing more than five other cities in the near future. Morphological analysis of 3-D building databases produces a suite of urban canopy parameters that can be incorporated into mesoscale meteorological, surface energy budget, and pollutant dispersion models. Additional computations can be performed to derive roughness length and displacement height using several common morphological formulae described in the literature. This paper summarizes the derivation of roughness length and displacement height for a 12-km{sup 2} section of downtown Los Angeles, 16-km{sup 2} section of downtown Phoenix, and 6-km{sup 2} section of downtown Salt Lake City. We correlate the computed roughness length and displacement height to underlying land use type.

Burian, S. J. (Steven J.); Brown, M. J. (Michael J.); Velugubantla, S. P. (Srinivas, P.)

2002-01-01

409

Assessing the accuracy of predicted ocean tide loading displacement values  

NASA Astrophysics Data System (ADS)

The accuracy of ocean tide loading (OTL) displacement values has long been assumed to be dominated by errors in the ocean tide models used, with errors due to the convolution scheme used considered very small (2-5%). However, this paper shows that much larger convolution errors can arise at sites within approximately 150 km of the coastline, depending on the method used to refine the discrete regularly spaced grid cells of the ocean tide model to better fit the coastline closest to the site of interest. If the local water mass redistribution approach is implemented, as used in the OLFG/OLMPP software recommended in the IERS 2003 conventions, OTL height displacement errors of up to around 20% can arise, depending on the ocean tide model used. Bilinear interpolation only, as used in the SPOTL and CARGA softwares for example, is shown from extensive global and regional comparisons of OTL displacement values derived from the different methods and softwares to be more appropriate. This is verified using GPS observations. The coastal refinement approach used in the OLFG/OLMPP software was therefore changed in August 2007 to use bilinear interpolation only. It is shown that with this change, OTL displacement values computed using OLFG/OLMPP, SPOTL and CARGA invariably agree to the millimetre level for coastal sites, and better than 0.2 mm for sites more than about 150 km inland.

Penna, N. T.; Bos, M. S.; Baker, T. F.; Scherneck, H.-G.

2008-12-01

410

Land expropriation and displacement in Bangladesh  

Microsoft Academic Search

This paper examines land grabbing in Bangladesh and views such seizures through the lens of displacement and land encroachment. Two different but potentially interacting displacement processes are examined. The first, the char riverine and coastal sediment regions that are in a constant state of formation and erosion, are contested sites ripe for power plays that uproot small producers on their

Shelley Feldman; Charles Geisler

2012-01-01

411

Planar inductive sensor for small displacement  

Microsoft Academic Search

This paper presents a meander type displacement inductive sensor, developed in printed circuit board (PCB) technology. It also describes design, realization and the input inductance measurement of sensor. The displacement in two directions (less than 0.5 mm) can be detected by using two sensor's elements (i.e. two pairs of meander coils). In each pair, one of the coils is fixed,

S. Duric; L. Nad; B. Biberdzic; M. Damnjanovic; L. Zivanov

2008-01-01

412

Displacement and Knowledge Construction in Literature Reviews.  

ERIC Educational Resources Information Center

Two literature reviews are interpreted to demonstrate how they are informed by what the author labels the "displacement story," that is, a story of how one prevailing professional paradigm is replaced by another. This study demonstrates how the narration, structure, and language in each review render particular tellings of the displacement story.…

Steinley, Gary

413

Proceedings of the Displaced Homemakers Conference.  

ERIC Educational Resources Information Center

The 1979 Displaced Homemakers Conference focused on developing awareness of services available from various Illinois agencies to displaced homemakers, generating the spirit and means for cooperative relationships among agencies serving them, and offering prototypes of how women's centers are attempting to coordinate the various services of state…

Illinois State Office of Education, Springfield. Div. of Adult Vocational and Technical Education.

414

Displacement damage analogs to ionizing radiation effects  

Microsoft Academic Search

We show that concepts, such as effective equivalent dose and the quality factor, which have long been found useful in comparing the effects of different kinds of ionizing radiation, are also applicable in correlating displacement damage effects in semiconductors. In the case of displacement damage, the energy deposition process is determined by the nonionizing energy loss (NIEL), instead of linear

Geoffrey P Summers; Edward A Burke; Michael A Xapsos

1995-01-01

415

Do Dogs (Canis familiaris) Understand Invisible Displacement?  

Microsoft Academic Search

Domestic dogs (Canis familiaris) perform above chance on invisible displacement tasks despite showing few other signs of possessing the necessary representational abilities. Four experiments investigated how dogs find an object that has been hidden in 1 of 3 opaque boxes. Dogs passed the task under a variety of control conditions, but only if the device used to displace the object

Emma Collier-Baker; Joanne M. Davis; Thomas Suddendorf

2004-01-01

416

Attenuation of surface-enhanced Raman scattering of magnetic-plasmonic FePt@Ag core-shell nanoparticles due to an external magnetic field  

NASA Astrophysics Data System (ADS)

The surface-enhanced Raman scattering (SERS) activities of Ag and FePt@Ag nanoparticle probes were examined using thiophenol as a Raman reporter molecule in the absence and presence of a magnetic field. Under external magnetic fields of different field strength, the SERS activities of both types of nanoparticles (NPs) were weakened as a function of magnetic field strength. The attenuation degree of SERS activity by the magnetic field in the case of FePt@Ag NPs is found to be two times higher than for Ag NPs, because the superparamagnetic FePt cores enhance the local magnetic field at the area of the Ag shells.

Trang, Nguyen T. T.; Thuy, Trinh T.; Mott, Derrick M.; Koyano, Mikio; Maenosono, Shinya

2013-06-01

417

Large displacement analysis of a marine riser  

SciTech Connect

A method of static analysis for a marine riser experiencing large displacements is presented. The method is suitable for analyzing a riser having a known top tension and a possible slippage at the top slip joint. Utilizing the stationary condition of a functional coupled with an equilibrium equation, one can conveniently obtain the equilibrium configuration numerically. The configuration is expressed in terms of the rectangular coordinates. The functional representing the energy and work of the riser system is expressed in terms of the horizontal coordinate which is parameterized in terms of the vertical depth instead of arc length. For a twodimensional problem, two multipliers must be included in the functional. One of the two represents the variable axial force along the length of the riser and the other corresponds to the strain energy per unit riser length due to bending. Utilizing the finite element method, a numerical procedure to obtain the configuration of static equilibrium is given. The resulting algebraic equations are highly nonlinear and the Newton-Raphson iterative procedure is used to solve the equations. An example is given.

Huang, T.; Chucheepsakul, S.

1985-03-01

418

Design of Nafion actuator with enhanced displacement  

NASA Astrophysics Data System (ADS)

A new actuator system has been developed. This actuator uses Nafion, a solid electrolyte, in combination with Platinum Copper (Pt-Cu) electrodes and mobile ions of Cu2+ to create much larger actuation displacement at smaller levels of applied voltage (1V or less). This actuator provides bending deformation. Large deformation is provided by electrode reaction of copper. Since this reaction is reversible, Cu electrode is not consumed by using polarity change of applied voltage. This actuation mechanism is different from others. Because the induction of the large deflection of Nafion, the large number of the mobile cations is essential. Although it is possible to induce a large deflection by applying a higher electric field as alternative way, this would introduce the electrolysis of water that is not desired unless the device is always submerged in water. To convert bending deformation to liner actuation, we designed a device using a pair of Nafion actuator, which is termed as loop actuator. This loop actuator can be designed into the device with large force by making parallel array. Solid polymer electrolyte-metal composite actuator contains water inside. Therefore coating that prevents water from evaporation is needed for its use in dry condition.

Uchida, Mikio; Xu, Chunye; Le Guilly, Marie; Taya, Minoru

2002-07-01

419

Interaction-induced atomic displacements revealed by drift-corrected dynamic force spectroscopy  

NASA Astrophysics Data System (ADS)

The three-dimensional force field above an NaCl(001) surface was measured on a fine grid by small amplitude dynamic force spectroscopy at room temperature. After careful drift corrections, maps in nominally equivalent symmetry planes as well as in sections parallel to the surface reveal distance-dependent shifts of characteristic atomic-sized features. These shifts reflect asymmetries of the probing tip apex but are mainly due to atomic displacements induced by short-range forces. In addition, weak decaying force oscillations with a period close to the interlayer spacing are detected at distances where no atomic-scale variations are expected. Stronger site-dependent changes appear in the interaction-induced energy dissipation.

Kawai, Shigeki; Glatzel, Thilo; Koch, Sascha; Baratoff, Alexis; Meyer, Ernst

2011-01-01

420

Energy dependence of electron damage and displacement threshold energy in 6H silicon carbide  

SciTech Connect

This paper reports on the frequency response of silicon carbide (SiC) light-emitting diodes that have been used to measure the energy dependence of displacement damage produced in 6H SiC by energetic electrons. The minimum electron energy required to produce displacement damage was determined to be 108 {plus minus} 7 keV, corresponding to an atomic displacement threshold energy, E{sub d}, of 21.8 {plus minus} 1.5 eV for the carbon atom. No evidence was seen of persistent damage due to displacement of silicon atoms. For electrons of energies greater than 0.5 MeV, the damage constant for lifetime degradation in SiC is lower than that for GaAs by more than three orders of magnitude, indicating a greatly superior resistance of SiC to displacement damage in most radiation environments.

Barry, A.L. (Communication Research Center, Ottawa (CA)); Lehmann, B.; Fritsch, D.; Braunig, D. (Hahn-Meitner-Inst. Berlin GmbH, Berlin (DE))

1991-12-01

421

Rotor Displacement of the Ultrasonic Motor Having an Angular Displacement Self-Correction Function  

NASA Astrophysics Data System (ADS)

This paper deals with the experimental investigation for confirmation of rotor displacement of the ultrasonic stepping motor having an angular displacement self-correction function. The experiment focused on the relationship between the rotor’s vibration displacement and its staying position for the self-correction. The result proved that the rotor always stays at the position where the displacement is smallest by cutting a slit into the rotor. Moreover, it has also been found that the stable self-correction of rotor angular displacement depends upon both the rotor driving frequency and rotor clamping force.

Chen, Xiaoduo; Kusakabe, Chiharu; Tomikawa, Yoshiro; Takano, Takehiro

1993-09-01

422

Spatial displacement correlations in polymeric systems  

NASA Astrophysics Data System (ADS)

The spatial correlations of the monomer displacements are studied via molecular-dynamics simulations of a melt of fully flexible, unentangled polymer chains with different length, interacting potential, density, and temperature. Both the scalar and the vector characters of the correlations are considered and their extension quantified in terms of suitable dynamical correlation lengths. Displacements performed at both short, i.e., vibrational, and long times, i.e., comparable to the structural relaxation time, are investigated. On both time scales the spatial correlations are modulated according to the radial distribution function g(r) to an extent which is determined by the character of the correlations, the time scale of the displacements and the structural slowing down. The spatial correlations of the short-time displacements have clear directional character. The modulus correlations of the long-time displacements are more marked, especially for sluggish states. Analogous findings are found by experiments on colloids. By inspecting the dynamical heterogeneities of states with slowed-down dynamics, it is observed that fast monomers exhibit correlations which are stronger and more differing from the bulk than the slow ones. It is shown that states with identical average vibrational monomer displacement exhibit identical spatial correlations of the monomer displacements pertaining to the subsets of the fast and the slow monomers characterizing both the short-time and the long-time dynamical heterogeneities.

Puosi, F.; Leporini, D.

2012-04-01

423

Spatial displacement correlations in polymeric systems.  

PubMed

The spatial correlations of the monomer displacements are studied via molecular-dynamics simulations of a melt of fully flexible, unentangled polymer chains with different length, interacting potential, density, and temperature. Both the scalar and the vector characters of the correlations are considered and their extension quantified in terms of suitable dynamical correlation lengths. Displacements performed at both short, i.e., vibrational, and long times, i.e., comparable to the structural relaxation time, are investigated. On both time scales the spatial correlations are modulated according to the radial distribution function g(r) to an extent which is determined by the character of the correlations, the time scale of the displacements and the structural slowing down. The spatial correlations of the short-time displacements have clear directional character. The modulus correlations of the long-time displacements are more marked, especially for sluggish states. Analogous findings are found by experiments on colloids. By inspecting the dynamical heterogeneities of states with slowed-down dynamics, it is observed that fast monomers exhibit correlations which are stronger and more differing from the bulk than the slow ones. It is shown that states with identical average vibrational monomer displacement exhibit identical spatial correlations of the monomer displacements pertaining to the subsets of the fast and the slow monomers characterizing both the short-time and the long-time dynamical heterogeneities. PMID:22559500

Puosi, F; Leporini, D

2012-04-28

424

Attomolar determination of coumaphos by electrochemical displacement immunoassay coupled with oligonucleotide sensing.  

PubMed

Coumaphos, an organophosphorus pesticide (OP) used worldwide, has raised serious public concerns due to its positive association with major types of cancer. Herein, a novel method for attomolar coumaphos detection was developed on the basis of an electrochemical displacement immunoassay coupled with oligonucleotide sensing. An optimized displacement immunoassay was constructed to improve the binding efficiency of an antigen-antibody pair, and a guanine-rich single-strand DNA label, in combination with oligonucleotide sensing, was used to amplify the detection signal with "direct" relationship to the analyte. As a result, coumaphos was sensitively determined from the enhanced catalytic cycle of guanine-Ru(bpy)(3)(2+) by chronoamperometry. The limit of detection (LOD) was down to 0.18 ng L(-1) (S/N = 3), which is equal to 49.6 amol in a sample solution of 100 ?L. In comparison with conventional methods, the proposed method has the lowest LOD and better accessibility to high-throughput sensing systems. Besides, it can complete the whole analysis process in under 50 min and exhibits good performance of excellent selectivity to the OPs. With regard to the advantages of rapidity, convenience, low cost, and ease of operation, the proposed method has provided a promising platform capable of fast and in-field OP detection, which may make the system promising for potential applications in the detection of other small molecules. PMID:22934793

Dai, Zong; Liu, Hui; Shen, Yudong; Su, Xingpeng; Xu, Zhenlin; Sun, Yuanming; Zou, Xiaoyong

2012-09-11

425

Effects of threshold displacement energy on defect production by displacement cascades in ?, ? and ?-LiAlO2  

NASA Astrophysics Data System (ADS)

Threshold displacement energy evaluation and a series of displacement cascade simulations in ?, ?, and ?-LiAlO2 were performed using molecular dynamics. Threshold displacement energy evaluations indicated that higher absolute ionic charge values and larger densities both increase threshold displacement energy. The displacement cascade simulations suggest that the influence of different crystal structures on the number of interstitial atoms generated in a displacement cascade is explainable almost entirely by the difference of the threshold displacement energy.

Tsuchihira, H.; Oda, T.; Tanaka, S.

2013-11-01

426

Anion-exchange displacement centrifugal partition chromatography.  

PubMed

Ion-exchange displacement chromatography has been adapted to centrifugal partition chromatography. The use of an ionic liquid, benzalkonium chloride, as a strong anion-exchanger has proven to be efficient for the preparative separation of phenolic acid regioisomers. Multigram quantities of a mixture of three hydroxycinnamic acid isomers were separated using iodide as a displacer. The displacement process was characterized by a trapezoidal profile of analyte concentration in the eluate with narrow transition zones. By taking advantage of the partition rules involved in support-free liquid-liquid chromatography, a numerical separation model is proposed as a tool for preliminary process validation and further optimization. PMID:15516108

Maciuk, Alexandre; Renault, Jean-Hugues; Margraff, Rodolphe; Trébuchet, Philippe; Zèches-Hanrot, Monique; Nuzillard, Jean-Marc

2004-11-01

427

Loading effects on time-variable gravity and surface displacements  

NASA Astrophysics Data System (ADS)

The global circulation of surface geophysical fluids (e.g. atmosphere, ocean hydrology) induce mass redistribution at the Earth's surface, and therefore gravity variations and surface deformation, over a large frequency domain. With the help of Love numbers, or the Green's function formalism, an output from general circulation models (GCM), they can be modeled with a high precision on an operational basis. We present here the computations of time-variable gravity and surface displacements, due to atmospheric, non-tidal oceanic and continental hydrological loading, and show the improvement in terms of reduction of the noise signal in GRACE KBRR residuals, Jason and Topex/Poseidon crossovers, as well as surface displacement observations (GPS, SLR or VLBI).

Boy, J.; Gegout, P.; Hinderer, J.; Luthcke, S. B.; Pavlis, E. C.; Lemoine, F. G.; Rowlands, D. D.

2008-12-01

428

Molecular Dynamics Simulations of Displacement Cascades in Single and Polycrystalline Zirconia  

SciTech Connect

Displacement cascades in zirconia have been studied using classical molecular dynamics simulations. Polycrystalline zirconia with nano-meter grains were created using Voronoi polyhedra construction and studied in comparison with single crystalline zirconia. The results show that displacement cascades with similar kinetic energy generated larger number of displaced atoms in polycrystalline than in the single crystal structure. The fraction of atoms with coordination number change was also higher in polycrystalline zirconia that was explained to be due to the diffusion of oxygen and relaxation at grain boundaries.

Du Jincheng [Department of Materials Science and Engineering, Center for Advanced Scientific Computing and Modeling, University of North Texas (United States)

2009-03-10

429

Local Structure of Displacively Disordered Pyrochlore Dielectrics  

SciTech Connect

Local cation environments in the pyrochlore dielectrics A{sub 2}B{sub 2}O6O' = (Bi,M){sub 2}(M,Nb){sub 2}O{sub 6}O' (M = Zn, Fe) were determined from the extended X-ray absorption fine structure. The A cations and O' ions are displaced from their ideal positions, yielding the effective (4 + 2 + 2) coordination for the A cations. The A-cation displacements are directed toward a pair of the framework O atoms; the specific displacement directions are determined by the nature of the A cations (i.e., Bi, Zn, Fe) and the local Nb/Zn (or Nb/Fe) B-site configurations. Local correlations among the atomic displacements and both [A{sub 4}O'] and [A{sub 2}B{sub 2}O] configurations provide near-ideal bond valence sums for all constituent species in these pyrochlore structures.

Krayzman,V.; Levin, I.; Woicik, J.

2007-01-01

430

Dynamics and Structure of Energetic Displacement Cascades.  

National Technical Information Service (NTIS)

This paper summarizes recent progress in the understanding of energetic displacement cascades and the primary state of damage in metals. On the theoretical side, the availability of supercomputers has greatly enhanced our ability to simulate cascades by m...

R. S. Averback T. Diaz de la Rubia R. Benedek

1987-01-01

431

Inverted liver with suprahepatic, anteriorly displaced gallbladder.  

PubMed

A suprahepatic, anteriorly displaced gallbladder in association with an inverted liver is an extremely rare congenital anomaly. We report the clinical and radiologic findings associated with a 78-year-old woman presenting with shortness of breath, desaturation, hypercapnia and hypoxemia. An abnormal chest radiograph demonstrated right hemi-diaphragmatic elevation consistent with a possible eventration. Subsequent imaging by computed tomography (CT) demonstrated an inverted liver with an anteriorly displaced, suprahepatic gallbladder. PMID:20666167

Hibbs, Harold; Ahmad, Usman

432

The displacement cascade in ceramic oxides  

NASA Astrophysics Data System (ADS)

The displacement cascade in ceramic oxides is studied using the atomic scattering methods of Lindhard et al. and the Monte Carlo TRIM methods of Biersack et al. The results concentrate on the effects of cascade energy and material mass ratio. It is seen that the heavy metal atom is preferentially displaced relative to the lighter O atom and that compositional changes can occur on the scale of the cascade.

Parkin, Don. M.

1990-02-01

433

Polymer displacement in dye-affinity chromatography  

Microsoft Academic Search

Displacement of lactate dehydrogenase from dye-affinity matrices with poly(ethyleneimine) (PEI) was shown to be an effective elution strategy. It resulted in better recoveries and sharper elution profiles than traditional non-specific elution while the purification factors were unchanged. The elution is assumed to proceed via displacement of bound protein by PEI when the polymer binds to the dye-ligands. Complete elution of

Igor Yu. Galaev; Pär Arvidsson; Bo Mattiasson

1995-01-01

434

Displacement analysis of a bend plate test with mechanical loading and laser heating  

SciTech Connect

The surface displacment of a steel plate caused by a permanent deformation as a result of local yielding was modeled by a finite element analysis. The local yielding occurs when a small area of the plate is heated by a laser beam. The calculated displacments are in good agreement with the preliminary experimental data obtained using a bend specimen with laser heating at the University of Alabama at Huntsville. It has been shown computuationally and optically that the relative displacments are less than 1mm near the laser heated area of the specimen. The results demonstrate that the experimental approach is a feasible technique for determining the residual stress under multiaxial stress field.

Lam, P.S.

1997-09-01

435

Spectral overlap in direct measurements of displaced single-photon states  

NASA Astrophysics Data System (ADS)

Many sophisticated quantum states of light display non-classical, characteristic oscillations in their photon statistics altering with respect to the applied displacement. In order to detect these oscillations the mode matching between the studied state and the displacement field plays a crucial role. Only recently the developments in the photon counting techniques have allowed the direct measurements of the photon-number distributions of quantum states. We investigate the properties of displaced single photons by applying time-multiplexed detection of photon statistics and quantify the value of the mode overlap.

Laiho, K.; Avenhaus, M.; Cassemiro, K. N.; Silberhorn, C.

2011-10-01

436

Development and evolution of character displacement.  

PubMed

Character displacement occurs when competition for either resources or successful reproduction imposes divergent selection on interacting species, causing divergence in traits associated with resource use or reproduction. Here, we describe how character displacement can be mediated either by genetically canalized changes (i.e., changes that reflect allelic or genotype frequency changes) or by phenotypic plasticity. We also discuss how these two mechanisms influence the tempo of character displacement. Specifically, we suggest that, under some conditions, character displacement mediated by phenotypic plasticity might occur more rapidly than that mediated by genetically canalized changes. Finally, we describe how these two mechanisms may act together and determine character displacement's mode, such that it proceeds through an initial phase in which trait divergence is environmentally induced to a later phase in which divergence becomes genetically canalized. This plasticity-first hypothesis predicts that character displacement should be generally mediated by ancestral plasticity and that it will arise similarly in multiple, independently evolving populations. We conclude by highlighting future directions for research that would test these predictions. PMID:22257002

Pfennig, David W; Pfennig, Karin S

2012-01-18

437

Displacement sensor for indoor machine calibrations.  

PubMed

This paper presents a simple displacement sensor for indoor machine calibrations. The sensor, which is placed in the path of a diverging laser beam, consists of two plane mirror pieces laterally displaced with the line joining their centers initially held perpendicular to the optical axis of the beam during the displacement of the sensor with one of the mirrors always traveling along the optical axis of the laser beam. The optical signals from the two mirrors are combined and a simple detector at the interference plane counts the fringes during the sensor displacement. The sensor could be mounted on the moving head of any mechanical machine, e.g., the lathe machine for displacement calibration. The device has been tested over a range of 10 cm beyond a distance of 150 cm from a diverging laser source giving an accuracy of 1.1015 ?m. Theoretical modeling, simulation, and experimental results are presented which establish that the proposed sensor can be used as a promising displacement measuring device. PMID:23736230

Mudassar, Asloob Ahmad; Butt, Saira

2013-05-20

438

Comparison of second cancer risk due to out-of-field doses from 6-MV IMRT and proton therapy based on 6 pediatric patient treatment plans  

PubMed Central

Background and Purpose This study compared 6-MV IMRT and proton therapy in terms of organ specific second cancer lifetime attributable risks (LARs) caused by scattered and secondary out-of-field radiation. Material and Methods Based on simulated organ doses, excess relative and excess absolute risk models were applied to assess organ-specific LARs. Two treatment sites (cranium and central spine) were considered involving 6 treatment volumes and 6 patient ages (9-month, 4-year, 8-year, 11-year, 14-year, and adult). Results The LARs for thyroid cancer from a 6 cm diameter field treating a brain lesion in a 4-year old patient were estimated to be 1.1% and 0.3% in passive proton therapy and IMRT, respectively. However, estimated LARs for bladder cancer, more than 25 cm from the field edge for the same patient and treatment field, were estimated to be 0.2% and 0.02% from IMRT and proton therapy, respectively. Risks for proton beam scanning was found to be an order of magnitude smaller compared to passive proton therapy. Conclusion In terms of out-of-field risks, IMRT offers advantage close to the primary field and an increasing advantage for passive proton therapy is noticed with increasing distance to the field. Scanning proton beam therapy shows the lowest risks.

Athar, Basit S.; Paganetti, Harald

2010-01-01

439

Experimental analysis of the contribution of swimming and drifting to the displacement of reef fish larvae  

Microsoft Academic Search

The extent to which behaviour affects the dispersal of pelagic larvae in reef fishes has been a topic of major discussion\\u000a among marine ecologists. Here, we experimentally quantified the extent to which the displacement of late-stage larvae of Abudefduf saxatilis is due to active movement (i.e. swimming) and drifting. We consider drifting as the component of larval displacement accounted\\u000a for

J. Derek Hogan; Camilo Mora

2005-01-01

440

A New Class of Inhomogeneous Cosmological Models with Electromagnetic Field in Normal Gauge for Lyra’s Manifold  

Microsoft Academic Search

A new class of exact solutions of Einstein’s modified field equations in inhomogeneous space-time for perfect fluid distribution\\u000a with electromagnetic field is obtained in the context of normal gauge for Lyra’s manifold. We have obtained solutions by considering\\u000a the time dependent displacement field. The source of the magnetic field is due to an electric current produced along the z-axis. Only

Anirudh Pradhan; H. Amirhashchi; H. Zainuddin

2011-01-01

441

Radiation damage due to electromagnetic showers  

Microsoft Academic Search

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

Igor Rakhno; Nikolai Mokhov; Sergei Striganov

2008-01-01

442

A 3D displacement measurement methodology for anisotropic porous cellular foam materials  

Microsoft Academic Search

This paper presents a new testing methodology for three dimensional (3D) full-field displacement mapping at the surface of elastic materials under static loading, here with a special focus on macroscopic behaviour of an anisotropic porous cellular foam. Three displacement components on four adjacent surfaces are estimated for cubic samples of the foam using a dual-camera 3D image correlation system. The

Rémi Guastavino; Peter Göransson

2007-01-01

443

An opening displacement characteristic determined by high-current anode phenomena of vacuum interrupter  

Microsoft Academic Search

A vacuum interrupter reaches its interruption limit once high-current anode phenomena occur. It is well-known that contact diameter, contact material, and magnetic field have a significant influence on high-current anode phenomena formation. However, an opening displacement characteristic of movable contact is another contribution for an anode spot formation. The objective of this paper is to propose an opening displacement characteristic

Liqiong Sun; Li Yu; Zhiyuan Liu; Jianhua Wang; Yingsan Geng

2011-01-01

444

Does juvenile competition explain displacement of a native crayfish by an introduced crayfish?  

Microsoft Academic Search

The coldwater crayfish Orconectes eupunctus is endemic to the Spring and Eleven Point Rivers of Arkansas and Missouri, and appears to have been displaced from a portion\\u000a of its range by the recently introduced ringed crayfish Orconectes neglectus. We examined competition among juveniles as a potential mechanism for this crayfish species displacement through laboratory\\u000a and field experiments. Orconectes eupunctus juveniles

Eric R. Larson; Daniel D. Magoulick

2009-01-01

445

On the finite displacement problem of a hollow cylinder under internal and external pressures  

Microsoft Academic Search

Using the method of successive approximations we find of this boundary-value problem the first-and second-order solutions. And then we obtain the formulae in the second approximation for the displacement, strain, and stress fields. Also, our results show that after deformation (i) a cross-section of the cylinder must be displaced into a plane section perpendicular to the central axis of the

Huang Ze-yan

1984-01-01

446

Simulation of foam displacement in porous media  

SciTech Connect

Foam is an excellent fluid for achieving mobility control of gas in porous media. Practical application of foams for EOR processes, however requires a predictive model of foam displacement. Further, quantitative information on foam-flow behavior at reservoir flow rates and pressures is required as input to any field-scale modeling. An experimental and mechanistic-modeling study is reported for the transient flow of foam through 1.3 {mu}m{sup 2} (1.3 D) Boise sandstone at backpressures in excess of 5 MPa (700 psi) over a quality range from 0.80 to 0.99. Total superficial velocities range from as little as 0.42 to 2.20 m/day (1.4 ft/day to 7 ft/day). Sequential pressure taps and gamma-ray densitometry measure flow resistance and in-situ liquid saturations, respectively. We garner experimental pressure and saturation profiles in both the transient and steady states. Adoption of a mean-size foam-bubble conservation equation along with the traditional reservoir simulation equations allows mechanistic foam simulation. Since foam mobility depends heavily upon its texture, the bubble population balance is both useful and necessary as the role of foam texture must be incorporated into any model which seeks accurate prediction of flow properties. Our model employs capillary-pressure-dependent kinetic expressions for lamellae generation and coalescence and also a term for trapping of lamellae. Additionally, the effects of surfactant chemical transport are included. We find quantitative agreement between experimental and theoretical saturation and pressure profiles in both the transient and steady states.

Kovscek, A.R.; Patzek, T.W.; Radke, C.J.

1993-08-01

447

Closed form evaluation of time domain fields due to Rao-Wilton-Glisson sources for use in marching-on-in-time based EFIE solvers  

Microsoft Academic Search

Often, spatial Rao-Wilton-Glisson (RWG) functions with polynomial temporal signatures are used in the construction of marching-on-in-time (MOT) based electric field integral equation (EFIE) solvers. While the efficient evaluation of fields generated by RWG sources with time-harmonic temporal dependence has been studied extensively, the same is not true for transient RWG sources. Here, it is shown that the convolution between RWG

M. Lu; E. Michielssen

2002-01-01

448

Fuzzy system models (FSMs) for analysis of rock mass displacement caused by underground mining in soft rock strata  

Microsoft Academic Search

In this paper, the mathematical theory of fuzzy probability measure (FPMs) is used for the problems of rock mass displacements and deformation due to underground excavation, especially mining in soft rock strata. A fuzzy system model is developed for the movement and deformation of rock mass on the basis of the assumption that the displacement and deformation of rock mass

Li Wen-xiu; Li Hai-ning

2009-01-01

449

Elastoplastic stress–strain analysis of buried steel pipelines subjected to fault displacements with account for service loads  

Microsoft Academic Search

This paper presents an analytical model for stress–strain analysis of buried steel pipelines subjected to active fault displacements, accounting for internal pressure and temperature variation ?T (a difference between the operational temperature and the temperature of pipelay). Along with the longitudinal stresses and strains arising from combined bending and tension due to fault displacements, additional hoop and axial stresses and

Oleg V. Trifonov; Vladimir P. Cherniy

450

Public self-consciousness moderates the link between displacement behaviour and experience of stress in women.  

PubMed

When stressed, people typically show elevated rates of displacement behaviour--activities such as scratching and face touching that seem irrelevant to the ongoing situation. Growing evidence indicates that displacement behaviour may play a role in regulating stress levels, and thus may represent an important component of the coping response. Recently, we found evidence that this stress-regulating effect of displacement behaviour is found in men but not in women. This sex difference may result from women's higher levels of public self-consciousness, which could inhibit expression of displacement behaviour due to the fear of projecting an inappropriate image. Here, we explored the link between public self-consciousness, displacement behaviour and stress among 62 healthy women (mean age?=?26.59 years; SD?=?3.61). We first assessed participants' public self-consciousness, and then quantified displacement behaviour, heart rate and cognitive performance during a Trier Social Stress Test (TSST) and used self-report questionnaires to assess the experience of stress afterwards. Public self-consciousness was negatively correlated with rate of displacement behaviour, and positively correlated with both the subjective experience of stress post-TSST and the number of mistakes in the cognitive task. Moderation analyses revealed that for women high in public self-consciousness, high levels of displacement behaviour were associated with higher reported levels of stress and poorer cognitive performance. For women low in public self-consciousness, stress levels and cognitiv