WorldWideScience

Sample records for current plate motions

  1. Current plate motions across the Red Sea

    Science.gov (United States)

    Chu, Dezhi; Gordon, Richard G.

    1998-11-01

    A new objective method is used to estimate precisely 64 rates of seafloor spreading since chron 2A (3.2 Ma) from all the Red Sea magnetic profiles available from 15.9° to 26°N. The fastest spreading rate, ~16 mm yr-1, occurs near 18°N, whereas the slowest rate, 10 mm yr-1, occurs at 25.5°N and is consistent with the rate predicted from Arabia-Nubia data to the south. The standard deviation of the spreading rates is 0.8 mm yr-1, much smaller than the median standard deviation of 4 mm yr-1 previously assigned to spreading rates in the global plate-motion model NUVEL-1 (DeMets et al. 1990). The fit to the spreading rates, as well as the locations of earthquakes in and near the Red Sea, indicate that spreading south of approximately 17.7°N is less than the full rate of spreading between the Arabian and Nubian plates. The Red Sea spreading centre is instead usefully interpreted as the boundary between the Arabian Plate and a Danakil microplate that includes the subaerial Danakil block and a larger oceanic portion of lithosphere. Despite the absence of reliable azimuths of transform faults in the Red Sea, all components of the angular velocity of Arabia relative to Nubia are usefully constrained from just the 45 relevant spreading rates. The new compact 95 per cent confidence region of the angular velocity excludes prior estimates based on only four and two spreading rates by Chase (1978) and Jestin et al. (1994), respectively. 19 spreading rates in the southern Red Sea are used to estimate the angular velocity between the Danakil microplate and Arabia. An approach based on singular value decomposition shows that without slip vectors only two of the three components of the angular velocity of the Danakil microplate relative to Arabia or Nubia are usefully constrained, but that all three components are usefully constrained if one earthquake slip vector is included.

  2. Current Arabian Plate Motion From Campaign GPS Measurements in Saudi Arabia: Preliminary Results

    Science.gov (United States)

    Almuslmani, B.; Teferle, F. N.; Bingley, R. M.; Moore, T.

    2007-12-01

    Current investigations of the motions of the Arabian and its neighboring plates are primarily based on GPS measurements obtained in the surrounding areas of the Arabian plate, with few stations actually located on the Arabian plate itself in the Kingdom of Saudi Arabia. In order to advance the knowledge of the dynamics of the Arabian plate and its intra-plate deformations, the General Directorate of Military Survey (GDMS), through collaboration with the Institute of Engineering Surveying and Space Geodesy (IESSG), densified the GPS network in Saudi Arabia, covering nearly two thirds of the tectonic plate. Since July 2002, a network of 32 GPS stations has been established at locations of the Saudi Arabia geodetic network. At all of these GPS stations a concrete pillar has been used as the monument and the locations have been selected in order to give the broadest distribution of observing sites. During 2005, 27 additional GPS stations in the Hejaz and Asser Mountains, and the Farasan Islands, all in south-western Saudi Arabia, have been established, for which the past and future campaign GPS measurements will provide valuable data for investigations of crustal deformations close to the plate boundaries between the Nubia, Somalian and Arabian plates. In this presentation we will show results in the form of velocity field and plate motion estimates based on data from at least three campaigns occupying the initial 32 GDMS GPS network stations, but also from a number of IGS stations in the region. Our reference frame is aligned to ITRF2005 and uses approximately 40 IGS reference frame stations located on all major tectonic plates, e.g. Nubia and Somalia, surrounding the Arabian plate. Furthermore, we apply absolute satellite and receiver antenna phase center models together with newly available GPS products from a recent global re-processing effort.

  3. Localised Plate Motion on Venus

    Science.gov (United States)

    Ghail, R. C.

    1996-03-01

    The volcanic and tectonic features observed in Dali Vinculum, Parga Vinculum and Imdr Regio are concentrated at long, narrow, curvilinear zones, with relatively minor volcanism and tectonism between these zones. These zones, whilst more diffuse than terrestrial plate boundaries, nevertheless define the margins of tectonic plates. In contrast to Earth, however, it appears that venusian plates are neither created nor destroyed by lateral motion. Rather, plates are thinned and intruded at vincula plate boundaries, vertically accreted by small-scale intra-plate (planitia) volcanism and perhaps destroyed by delamination of thickened crust in tesserae and montane regions such as Thetis Regio and Ishtar Terra. The diversity in age both between and within these three areas together with the evidence for infrequent, small scale resurfacing in the planitiae are difficult to reconcile with a non-uniformitarian geological process.

  4. Horizontal versus vertical plate motions

    Directory of Open Access Journals (Sweden)

    M. Cuffaro

    2006-07-01

    Full Text Available We review both present and past motions at major plate boundaries, which have the horizontal component in average 10 to 100 times faster (10–100 mm/yr than the vertical component (0.01–1 mm/yr in all geodynamic settings. The steady faster horizontal velocity of the lithosphere with respect to the upward or downward velocities at plate boundaries supports dominating tangential forces acting on plates. This suggests a passive role of plate boundaries with respect to far field forces determining the velocity of plates. The forces acting on the lithosphere can be subdivided in coupled and uncoupled, as a function of the shear at the lithosphere base. Higher the asthenosphere viscosity, more significant should be the coupled forces, i.e., the mantle drag and the trench suction. Lower the asthenosphere viscosity, more the effects of uncoupled forces might result determinant, i.e., the ridge push, the slab pull and the tidal drag. Although a combination of all forces acting on the lithosphere is likely, the decoupling between lithosphere and mantle suggests that a torque acts on the lithosphere independently of the mantle drag. Slab pull and ridge push are candidates for generating this torque, but, unlike these boundary forces, the advantage of the tidal drag is to be a volume force, acting simultaneously on the whole plates, and being the decoupling at the lithosphere base controlled by lateral variations in viscosity of the low-velocity layer.

  5. The dynamics of Cenozoic and Mesozoic plate motions

    OpenAIRE

    Lithgow-Bertelloni, C.; Richards, M. A.

    1998-01-01

    Our understanding of the dynamics of plate motions is based almost entirely upon modeling of present-day plate motions. A fuller understanding, however, can be derived from consideration of the history of plate motions. Here we investigate the kinematics of the last 120 Myr of plate motions and the dynamics of Cenozoic motions, paying special attention to changes in the character of plate motions and plate-driving forces. We analyze the partitioning of the observed surface velocity field into...

  6. Chaotic Motion of Corrugated Circular Plates

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Large deflection theory of thin anisotropic circular plates was used to analyze the bifurcation behavior and chaotic phenomena of a corrugated thin circular plate with combined transverse periodic excitation and an in-plane static boundary load. The nonlinear dynamic equation for the corrugated plate was derived by employing Galerkin's technique. The critical conditions for occurrence of the homoclinic and subharmonic bifurcations as well as chaos were studied theoretically using the Melnikov function method. The chaotic motion was also simulated numerically using Maple, with the Poincaré map and phase curve used to evaluate when chaotic motion appears. The results indicate some chaotic motion in the corrugated plate. The method is directly applicable to chaotic analysis of an isotropic circular plate.

  7. Motion of the Scotia sea plates

    Science.gov (United States)

    Thomas, C.; Livermore, R.; Pollitz, F.

    2003-01-01

    Earthquake data from the Scotia Arc to early 2002 are reviewed in the light of satellite gravity and other data in order to derive a model for the motion of plates in the Scotia Sea region. Events with magnitude ???5, which occurred on or near the boundaries of the Scotia and Sandwich plates, and for which Centroid Moment Tensor (CMT) solutions are available, are examined. The newer data fill some of the previous sampling gaps along the boundaries of the Scotia and Sandwich plates, and provide tighter constraints on relative motions. Variations in the width of the Brunhes anomaly on evenly spaced marine magnetic profiles over the East Scotia Ridge provide new estimates of Scotia-Sandwich plate spreading rates. Since there are no stable fracture zones in the east Scotia Sea, the mean azimuth of sea floor fabric mapped by sidescan is used to constrain the direction of spreading. 18 new rate estimates and four azimuths from the East Scotia Ridge are combined with 68 selected earthquake slip vectors from the boundaries of the Scotia Sea in a least-squares inversion for the best-fitting set of Euler poles and angular rotation rates describing the 'present-day' motions of the Scotia and Sandwich plates relative to South America and Antarctica. Our preferred model (TLP2003) gives poles that are similar to previous estimates, except for Scotia Plate motion with respect to South America, which is significantly different from earlier estimates; predicted rates of motion also differ slightly. Our results are much more robust than earlier work. We examine the implications of the model for motion and deformation along the various plate boundaries, with particular reference to the North and South Scotia Ridges, where rates are obtained by closure.

  8. Tomography, the geoid and plate motions

    Science.gov (United States)

    Gable, Carl W.; O'Connell, Richard J.

    1991-01-01

    The dynamics of the earth's mantle and its relationship to mantle structure as revealed by seismic tomography, the geoid, and plate motions are discussed in a critical review of U.S. research from the period 1987-1990. Sections are devoted to plates and mantle convection; seismic anomalies, flow, and the geoid; subducted slabs and the 670-km discontinuity; the physical properties of the mantle; plumes; and computational and experimental modeling efforts. Also included is a comprehensive bibliography for the period.

  9. Computer animation of Phanerozoic plate motions

    Energy Technology Data Exchange (ETDEWEB)

    Scotese, C.R. (Univ. of Texas, Arlington, TX (United States). Dept. of Geology)

    1992-01-01

    Since 1985, the PALEOMAP Project, in collaboration with research groups both in the US and abroad, has assembled a digital model that describes global plate motions during the last 600 million years. In this paper the authors present a series of computer animations that dynamically illustrates the movement of continents and terranes, and the evolution of the ocean basins since the breakup of the late Precambrian supercontinent. These animations depict the motion of the plates from both equatorial and polar perspectives. Mesozoic and Cenozoic plate tectonic reconstructions are based on a synthesis of linear magnetic anomalies, fracture zone locations, intracontinental rifts, collision and thrust belts, and zones of strike-slip. Paleozoic plate reconstructions, though more speculative, are based on evidence of past subduction, continental collision, and inferred sea floor spreading. The relative longitudinal positions of the continents during the Paleozoic and the width of intervening oceans have been adjusted to best explain changing biogeographic and paleoclimatic patterns. A new paleomagnetic/hot spot reference frame has been constructed that combines paleomagnetic data compiled by Rob Van der Voo (1992) with inferred motion relative to a fixed frame of hot spots. Using probable Early Mesozoic and Paleozoic hot spot tracks on the major continents, the authors have extended plate motions relative to the hot spot reference frame back to 400 million years.

  10. Caribbean tectonics and relative plate motions

    Science.gov (United States)

    Burke, K.; Dewey, J. F.; Cooper, C.; Mann, P.; Pindell, J. L.

    1984-01-01

    During the last century, three different ways of interpreting the tectonic evolution of the Gulf of Mexico and the Caribbean have been proposed, taking into account the Bailey Willis School of a permanent pre-Jurassic deep sea basin, the Edward Suess School of a subsided continental terrain, and the Alfred Wegener School of continental separation. The present investigation is concerned with an outline of an interpretation which follows that of Pindell and Dewey (1982). An attempt is made to point out ways in which the advanced hypotheses can be tested. The fit of Africa, North America, and South America is considered along with aspects of relative motion between North and South America since the early Jurasic. Attention is given to a framework for reconstructing Caribbean plate evolution, the evolution of the Caribbean, the plate boundary zones of the northern and southern Caribbean, and the active deformation of the Caribbean plate.

  11. Longitudinal wave motion in width-constrained auxetic plates

    Science.gov (United States)

    Lim, Teik-Cheng

    2016-05-01

    This paper investigates the longitudinal wave velocity in auxetic plates in comparison to conventional ones, in which the plate is constrained from motion in the width direction. By taking into account the thickness change of the plate and its corresponding change in density, the developed wave velocity is casted not only as a function of Young’s modulus and density, but also in terms of Poisson’s ratio and longitudinal strain. Results show that density and thickness variations compensate for one another when the Poisson’s ratio is positive, but add up when the Poisson’s ratio is negative. Results also reveal that the classical model of longitudinal wave velocity for the plate is accurate when the Poisson’s ratio is about 1/3; at this Poisson’s ratio the influence from density and thickness variations cancel each other. Comparison between the current corrected model and the density-corrected Rayleigh-Lamb model reveals a number of consistent trends, while the discrepancies are elucidated. If the plate material possesses a negative Poisson’s ratio, the deviation of the actual wave velocity from the classical model becomes significant; auxeticity suppresses and enhances the wave velocity in compressive and tensile impacts, respectively. Hence the use of the corrected model is proposed when predicting longitudinal waves in width-constrained auxetic plates, and auxetic materials can be harnessed for effectively controlling wave velocities in thin-walled structures.

  12. RELATIVE MOTION AND DEFORMATION OF PACIFIC PLATE FROM SPACE GEODESY

    Institute of Scientific and Technical Information of China (English)

    JinShuanggen; ZhuWenyao

    2003-01-01

    The circum-Pacific tectonic system that contains of convergent, divergent and transform boundaries, is the most active region of volcanoes and earthquakes in the world, and involves many important theoretical questions in geosciences. The relative motion and deformation of Pacific plate is still an active subject of research. In this note, we analyze the deformation of Pacific plate and obtain reliable results of the relative motion rates at the circum-Pacific boundaries based on space geodetic data, which reveals the present-day motion characteristics of Pacific plate.

  13. Contemporary Crustal Motion and Deformation of South America Plate

    Institute of Scientific and Technical Information of China (English)

    JIN Shuanggen; ZHU Wenyao

    2003-01-01

    This paper presents the contemporary motion and active deformation of South America plate and relative motion of Nazca-South America plate using space geodetic data. The South America plate is moving at average 14.5 mm/a with an azimuth of 15.2° and shrinking in the west-east at 10. 9 mm/a. The geodetic deformations of sites with respect to the South America plate are in quite good agreement with the estimated deformations from NNR-NUVEL1A, but the deformation of the western South America regions is very large.

  14. A true polar wander model for Neoproterozoic plate motions

    Energy Technology Data Exchange (ETDEWEB)

    Ripperdan, R.L. (Weizmann Inst. of Science, Rehovot (Israel))

    1992-01-01

    Recent paleogeographic reconstructions for the interval 750--500 Ma (Neoproterozoic to Late Cambrian) require rapid rates of plate motion and/or rotation around an equatorial Euler pole to accommodate reconstructions for the Early Paleozoic. Motions of this magnitude appear to be very uncommon during the Phanerozoic. A model for plate motions based on the hypothesis that discrete intervals of rapid true polar wander (RTPW) occurred during the Neoproterozoic can account for the paleogeographic changes with minimum amounts of plate motion. The model uses the paleogeographic reconstructions of Hoffman (1991). The following constraints were applied during derivation of the model: (1) relative motions between major continental units were restricted to be combinations of great circle or small circle translations with Euler poles of rotation = spin axis; (2) maximum rates of relative translational plate motion were 0.2 m/yr. Based on these constraints, two separate sets of synthetic plate motion trajectories were determined. The sequence of events in both can be summarized as: (1) A rapid true polar wander event of ca 90[degree] rafting a supercontinent to the spin axis; (2) breakup of the polar supercontinent into two fragments, one with the Congo, West Africa, Amazonia, and Baltica cratons, the other with the Laurentia, East Gondwana, and Kalahari cratons; (3) great circle motion of the blocks towards the equator; (4) small circle motion leading to amalgamation of Gondwana and separation of Laurentia and Baltica. In alternative 1, rifting initiates between East Antarctica and Laurentia and one episode of RTPW is required. Alternative 2 requires two episodes of RTPW; and that rifting occurred first along the eastern margin and later along the western margin of Laurentia. Synthetic plate motion trajectories are compared to existing paleomagnetic and geological data, and implications of the model for paleoclimatic changes during the Neoproterozoic are discussed.

  15. Controlling the motion of multiple objects on a Chladni plate

    OpenAIRE

    2016-01-01

    The origin of the idea of moving objects by acoustic vibration can be traced back to 1787, when Ernst Chladni reported the first detailed studies on the aggregation of sand onto nodal lines of a vibrating plate. Since then and to this date, the prevailing view has been that the particle motion out of nodal lines is random, implying uncontrollability. But how random really is the out-of-nodal-lines motion on a Chladni plate? Here we show that the motion is sufficiently regular to be statistica...

  16. Plate Motions Predicted from Global Dynamic Models and Seismic Tomography: The Problem of North American Plate Motion

    Science.gov (United States)

    Liu, S.; King, S. D.; Adam, C. M.

    2016-12-01

    Seismic tomography is a snapshot of the mantle convection system and provides important constraints on Earth's internal dynamics. An increasing number of global seismic tomography models along with various rheological structures have been used to compute mantle flow pattern and the resulting surface expressions, including dynamic topography and geoid. Accurately predicting the plate motion from the mantle dynamic models is a challenge particularly with the newest generation of seismic tomography models (e.g., S40RTS, SAVANI), especially for the North American plate which only has a little subduction along it's boundary. The difficulties include the uncertainty of the velocity-to-density scaling, discrepancies between different seismic tomography models, and the computational technology to solve for global mantle flow with observationally constrained high resolution models. We use the code ASPECT (Advanced Solver for Problems in Earth CovecTion) to make a series of tests to derive mantle flow pattern from different global seismic tomography models and rheological structures. We further make a quantitative statistical comparison between the modeled and observed plate motions in terms of flow magnitude, flow direction, and plateness within each plate area. We investigate how the velocity-to-density scaling, the features of seismic tomography models, and the lateral rheological structures of the lithosphere and upper mantle influence the modeled plate motions. We find that the velocity-to-density scaling mainly changes the flow magnitude and has little impact on the flow direction. The results of different seismic tomography models are similar broadly but can be quite different in some regions. The presence of lateral viscosity variations including stiff cratons, weak plate boundary zones, and high viscosity slabs along with density variations from seafloor age and subducting slabs can improve the fit to observed plate motions. With a very small fraction of subduction

  17. Transient motion of thick anisotropic plates

    Science.gov (United States)

    Nayfeh, Adnan H.; Taylor, Timothy W.

    1991-01-01

    Analyses are developed for the response of anisotropic plate strips to a transient load. The load is taken in the form of a line load of normal stress on the surface or within the body of the strip. The characteristic free vibrational modes of the strip are derived and used to derive the secular equation for this case in closed form and to isolate the mathematical conditions for symmetric and antisymmetric wave mode propagation in completely separate terms. The applied loads are expanded in terms of these normal modes and the response of the plate is obtained by superposition of the appropriate components. Material systems of higher symmetry are contained implicitly in the analysis.

  18. Closure of the Africa-Eurasia-North America plate motion circuit and tectonics of the Gloria fault

    Science.gov (United States)

    Argus, Donald F.; Gordon, Richard G.; Demets, Charles; Stein, Seth

    1989-01-01

    The current motions of the African, Eurasian, and North American plates are examined. The problems addressed include whether there is resolvable motion of a Spitsbergen microplate, the direction of motion between the African and North American plates, whether the Gloria fault is an active transform fault, and the implications of plate circuit closures for rates of intraplate deformation. Marine geophysical data and magnetic profiles are used to construct a model which predicts about 4 mm/yr slip across the Azores-Gibraltar Ridge, and west-northwest convergence near Gibraltar. The analyzed data are consistent with a rigid plate model with the Gloria fault being a transform fault.

  19. Controlling the motion of multiple objects on a Chladni plate

    Science.gov (United States)

    Zhou, Quan; Sariola, Veikko; Latifi, Kourosh; Liimatainen, Ville

    2016-09-01

    The origin of the idea of moving objects by acoustic vibration can be traced back to 1787, when Ernst Chladni reported the first detailed studies on the aggregation of sand onto nodal lines of a vibrating plate. Since then and to this date, the prevailing view has been that the particle motion out of nodal lines is random, implying uncontrollability. But how random really is the out-of-nodal-lines motion on a Chladni plate? Here we show that the motion is sufficiently regular to be statistically modelled, predicted and controlled. By playing carefully selected musical notes, we can control the position of multiple objects simultaneously and independently using a single acoustic actuator. Our method allows independent trajectory following, pattern transformation and sorting of multiple miniature objects in a wide range of materials, including electronic components, water droplets loaded on solid carriers, plant seeds, candy balls and metal parts.

  20. A New Absolute Plate Motion Model for Africa

    Science.gov (United States)

    Maher, S. M.; Wessel, P.; Müller, D.; Harada, Y.

    2013-12-01

    The India-Eurasia collision, a change in relative plate motion between Australia and Antarctica, and the coeval ages of the Hawaiian Emperor Bend (HEB) and Louisville Bend of ~Chron 22-21 all provide convincing evidence of a global tectonic plate reorganization at ~50 Ma. Yet if it were a truly global event, then there should be a contemporaneous change in Africa absolute plate motion (APM) reflected by physical evidence somewhere on the Africa plate. This evidence might be visible in the Reunion-Mascarene bend, which exhibits many HEB-like features such as a large angular change close to ~50 Ma. Recently, the Reunion hotpot trail has been interpreted as a continental feature with incidental hotspot volcanism. Here we propose the alternative hypothesis that the northern portion of the chain between Saya de Malha and the Seychelles (Mascarene Plateau) formed as the Reunion hotspot was situated on the Carlsberg Ridge, contemporaneously forming the Chagos-Laccadive Ridge on the India plate. We have created a 4-stage model that explores how a simple APM model fitting the Mascarene Plateau can also satisfy the age progressions and geometry of other hotspot trails on the Africa plate. This type of model could explain the apparent bifurcation of the Tristan hotspot chain, the age reversals seen along the Walvis Ridge and the diffuse nature of the St. Helena chain. To test this hypothesis we have made a new African APM model that goes back to ~80 Ma using a modified version of the Hybrid Polygonal Finite Rotation Method. This method uses seamount chains and their associated hotspots as geometric constraints for the model, and seamount age dates to determine its motion through time. The positions of the hotspots can be moved to get the best fit for the model and to explore the possibility that the ~50 Ma bend in the Reunion-Mascarene chain reflects Africa plate motion. We will examine how well this model can predict the key features reflecting Africa plate motion and

  1. Observing tectonic plate motions and deformations from satellite laser ranging

    Science.gov (United States)

    Christodoulidis, D. C.; Smith, D. E.; Kolenkiewicz, R.; Klosko, S. M.; Torrence, M. H.

    1985-01-01

    The scope of geodesy has been greatly affected by the advent of artificial near-earth satellites. The present paper provides a description of the results obtained from the reduction of data collected with the aid of satellite laser ranging. It is pointed out that dynamic reduction of satellite laser ranging (SLR) data provides very precise positions in three dimensions for the laser tracking network. The vertical components of the stations, through the tracking geometry provided by the global network and the accurate knowledge of orbital dynamics, are uniquely related to the center of mass of the earth. Attention is given to the observations, the methodologies for reducing satellite observations to estimate station positions, Lageos-observed tectonic plate motions, an improved temporal resolution of SLR plate motions, and the SLR vertical datum.

  2. Observing tectonic plate motions and deformations from satellite laser ranging

    Science.gov (United States)

    Christodoulidis, D. C.; Smith, D. E.; Kolenkiewicz, R.; Klosko, S. M.; Torrence, M. H.

    1985-01-01

    The scope of geodesy has been greatly affected by the advent of artificial near-earth satellites. The present paper provides a description of the results obtained from the reduction of data collected with the aid of satellite laser ranging. It is pointed out that dynamic reduction of satellite laser ranging (SLR) data provides very precise positions in three dimensions for the laser tracking network. The vertical components of the stations, through the tracking geometry provided by the global network and the accurate knowledge of orbital dynamics, are uniquely related to the center of mass of the earth. Attention is given to the observations, the methodologies for reducing satellite observations to estimate station positions, Lageos-observed tectonic plate motions, an improved temporal resolution of SLR plate motions, and the SLR vertical datum.

  3. Eastern Indian Ocean microcontinent formation driven by plate motion changes

    Science.gov (United States)

    Whittaker, J. M.; Williams, S. E.; Halpin, J. A.; Wild, T. J.; Stilwell, J. D.; Jourdan, F.; Daczko, N. R.

    2016-11-01

    The roles of plate tectonic or mantle dynamic forces in rupturing continental lithosphere remain controversial. Particularly enigmatic is the rifting of microcontinents from mature continental rifted margins, with plume-driven thermal weakening commonly inferred to facilitate calving. However, a role for plate tectonic reorganisations has also been suggested. Here, we show that a combination of plate tectonic reorganisation and plume-driven thermal weakening were required to calve the Batavia and Gulden Draak microcontinents in the Cretaceous Indian Ocean. We reconstruct the evolution of these two microcontinents using constraints from new paleontological samples, 40Ar/39Ar ages, and geophysical data. Calving from India occurred at 101-104 Ma, coinciding with the onset of a dramatic change in Indian plate motion. Critically, Kerguelen plume volcanism does not appear to have directly triggered calving. Rather, it is likely that plume-related thermal weakening of the Indian passive margin preconditioned it for microcontinent formation but calving was triggered by changes in plate tectonic boundary forces.

  4. Vertical plate motions in the West Siberian Basin

    Science.gov (United States)

    Vibe, Yulia

    2014-05-01

    The West Siberian Basin is a sedimentary basin situated between the Ural Mountains and the Siberian Craton. The Basin has experienced several periods of subsidence and uplift since the arrival of the Siberian Traps c. 250 Ma. Although the Basin is extensively explored and hosts large reserves of Oil and Gas, the forces driving the vertical motions are poorly understood. In this work we attempt to analyse the amount, timing and location of subsidence and uplift in the Basin to shed light on the possible causes of these motions. A detailed description of sedimentary layers is published in a number of Soviet-era books and articles and serves as a basis for our research. This data is first converted into sediment grids through time. Subsequently, the sediments, the sediment load and the compaction are taken into account ('backstripping') to produce the depth of the Basin at respective time steps. With this technique we calculate the tectonic component of subsidence. Uncertainties related to uplift events are estimated by the unconformities in the stratigraphic charts. One of the possible driving forces of vertical motions is a change of force balance arising at plate boundaries. Since active plate tectonics have been absent from West Siberia since the formation of the Urengoy and Khodosey Rifts, c. 250Ma, we study the far-field tectonic effects as a potential driving mechanism. Indeed, some of the significant vertical events in the West Siberian Basin coincide with the major tectonic events around Siberia. An example is the spreading in the Arctic (Eurasian Basin) in the Eocene (56 Ma) which was synchronous with initiation of uplift events in the northern part of West Siberia. In the middle Oligocene (33 Ma), the northern and eastern parts of the basin were subjected to uplift as subsidence migrated southwards and the Basin rose above the sea level. This was coincident with the changes of plate motions in the northern North Atlantic and Indo-European collision.

  5. Ridge-spotting: A new test for Pacific absolute plate motion models

    Science.gov (United States)

    Wessel, Paul; Müller, R. Dietmar

    2016-06-01

    Relative plate motions provide high-resolution descriptions of motions of plates relative to other plates. Yet geodynamically, motions of plates relative to the mantle are required since such motions can be attributed to forces (e.g., slab pull and ridge push) acting upon the plates. Various reference frames have been proposed, such as the hot spot reference frame, to link plate motions to a mantle framework. Unfortunately, both accuracy and precision of absolute plate motion models lag behind those of relative plate motion models. Consequently, it is paramount to use relative plate motions in improving our understanding of absolute plate motions. A new technique called "ridge-spotting" combines absolute and relative plate motions and examines the viability of proposed absolute plate motion models. We test the method on six published Pacific absolute plate motions models, including fixed and moving hot spot models as well as a geodynamically derived model. Ridge-spotting reconstructs the Pacific-Farallon and Pacific-Antarctica ridge systems over the last 80 Myr. All six absolute plate motion models predict large amounts of northward migration and monotonic clockwise rotation for the Pacific-Farallon ridge. A geodynamic implication of our ridge migration predictions is that the suggestion that the Pacific-Farallon ridge may have been pinned by a large mantle upwelling is not supported. Unexpected or erratic ridge behaviors may be tied to limitations in the models themselves or (for Indo-Atlantic models) discrepancies in the plate circuits used to project models into the Pacific realm. Ridge-spotting is promising and will be extended to include more plates and other ocean basins.

  6. The Hawaii-Emperor Bend: Plate motion, plume motion, or both?

    Science.gov (United States)

    Wessel, P.

    2011-12-01

    The Hawaii-Emperor Bend (HEB) has become a lightening rod for studies of absolute plate motion (APM). Initially seen as the clearest evidence for an APM change over an approximately stationary hotspot, recent studies have suggested that the HEB represents no change in APM motion at all. Instead, it has been proposed that there was a rapid retardation of the southward motion of the underlying Hawaii plume at ~ 50 Ma while the Pacific plate continued its otherwise undisturbed westward motion. Some even see this development as further evidence that the hotspot hypothesis is fundamentally flawed and that no plumes exist. Although several lines of inquiry have lead to the revised interpretations of the HEB signature, there are in particular two principal observations that have prompted this proposed major revision: (a) Paleolatitudes inferred from basalt samples recovered from drill cores at several sites along the Emperor chain systematically imply a volcanic origin much further north than the present latitude of the Hawaiian hotspot, and (b) the age progressions along the Emperor and Louisville chains inferred from dated rock samples appear to diverge for ages older than ~55 Ma when a fixed hotspot reference frame is used to relate the two age progressions. While the latter discrepancy can be modeled with relative minor changes in the inter-hotspot distance between Hawaii and Louisville or by appealing to limited hotspot-ridge interactions, the paleolatitude anomaly at 78 Ma is almost 15 degrees. Unless this anomaly only partially reflects plume motion, its sheer magnitude may require a significant revision of Pacific tectonic history and could ultimately drive a stake through the heart of the hotspot hypothesis; critical new data on Louisville seamount paleolatitudes are required to resolve this puzzle. The HEB itself is constrained to have formed around 50-47 Ma, i.e., approximately Chron 21, which is a known period of significant and global plate reorganizations

  7. Ongoing glacial-isostatic adjustment and present-day motion of tectonic plates

    OpenAIRE

    2008-01-01

    The effect of glacial-isostatic adjustment (GIA) on the motion of tectonic plates is usually neglected. Employing a recently developed numerical approach, we examine the effect of glacial loading on the motion of the Earth’s main tectonic plates where we consider an elastic lithosphere of laterally variable strength and the plates losely connected by low viscous zones. Aim of the paper is to show the physical processes which controls the GIA induced horizontal motion and to assess the impact ...

  8. Alignment between seafloor spreading directions and absolute plate motions through time

    Science.gov (United States)

    Williams, Simon E.; Flament, Nicolas; Müller, R. Dietmar

    2016-02-01

    The history of seafloor spreading in the ocean basins provides a detailed record of relative motions between Earth's tectonic plates since Pangea breakup. Determining how tectonic plates have moved relative to the Earth's deep interior is more challenging. Recent studies of contemporary plate motions have demonstrated links between relative plate motion and absolute plate motion (APM), and with seismic anisotropy in the upper mantle. Here we explore the link between spreading directions and APM since the Early Cretaceous. We find a significant alignment between APM and spreading directions at mid-ocean ridges; however, the degree of alignment is influenced by geodynamic setting, and is strongest for mid-Atlantic spreading ridges between plates that are not directly influenced by time-varying slab pull. In the Pacific, significant mismatches between spreading and APM direction may relate to a major plate-mantle reorganization. We conclude that spreading fabric can be used to improve models of APM.

  9. Sensitivity analysis of the GNSS derived Victoria plate motion

    Science.gov (United States)

    Apolinário, João; Fernandes, Rui; Bos, Machiel

    2014-05-01

    Fernandes et al. (2013) estimated the angular velocity of the Victoria tectonic block from geodetic data (GNSS derived velocities) only.. GNSS observations are sparse in this region and it is therefore of the utmost importance to use the available data (5 sites) in the most optimal way. Unfortunately, the existing time-series were/are affected by missing data and offsets. In addition, some time-series were close to the considered minimal threshold value to compute one reliable velocity solution: 2.5-3.0 years. In this research, we focus on the sensitivity of the derived angular velocity to changes in the data (longer data-span for some stations) by extending the used data-span: Fernandes et al. (2013) used data until September 2011. We also investigate the effect of adding other stations to the solution, which is now possible since more stations became available in the region. In addition, we study if the conventional power-law plus white noise model is indeed the best stochastic model. In this respect, we apply different noise models using HECTOR (Bos et al. (2013), which can use different noise models and estimate offsets and seasonal signals simultaneously. The seasonal signal estimation is also other important parameter, since the time-series are rather short or have large data spans at some stations, which implies that the seasonal signals still can have some effect on the estimated trends as shown by Blewitt and Lavellee (2002) and Bos et al. (2010). We also quantify the magnitude of such differences in the estimation of the secular velocity and their effect in the derived angular velocity. Concerning the offsets, we investigate how they can, detected and undetected, influence the estimated plate motion. The time of offsets has been determined by visual inspection of the time-series. The influence of undetected offsets has been done by adding small synthetic random walk signals that are too small to be detected visually but might have an effect on the

  10. Motion of the Philippine Sea plate consistent with the NUVEL-1A model

    Science.gov (United States)

    Zang, Shao Xian; Chen, Qi Yong; Ning, Jie Yuan; Shen, Zheng Kang; Liu, Yong Gang

    2002-09-01

    We determine Euler vectors for 12 plates, including the Philippine Sea plate (PH), relative to the fixed Pacific plate (PA) by inverting the earthquake slip vectors along the boundaries of the Philippine Sea plate, GPS observed velocities, and 1122 data from the NUVEL-1 and the NUVEL-1A global plate motion model, respectively. This analysis thus also yields Euler vectors for the Philippine Sea plate relative to adjacent plates. Our results are consistent with observed data and can satisfy the geological and geophysical constraints along the Caroline (CR)-PH and PA-CR boundaries. The results also give insight into internal deformation of the Philippine Sea plate. The area enclosed by the Ryukyu Trench-Nankai Trough, Izu-Bonin Trench and GPS stations S102, S063 and Okino Torishima moves uniformly as a rigid plate, but the areas near the Philippine Trench, Mariana Trough and Yap-Palau Trench have obvious deformation.

  11. Evaluation of motion platform embedded with force plate-instrumented treadmill

    National Research Council Canada - National Science Library

    Emily H Sinitski; Edward D Lemaire; Natalie Baddour

    2015-01-01

    ... with a dual-belt treadmill and two force plates. The goal of this article was to investigate the performance characteristics associated with a treadmill-motion platform configuration and how system operation can affect the data collected...

  12. Brownian motion of a charged test particle in vacuum between two conducting plates

    Science.gov (United States)

    Yu, Hongwei; Chen, Jun

    2004-12-01

    The Brownian motion of a charged test particle caused by quantum electromagnetic vacuum fluctuations between two perfectly conducting plates is examined and the mean squared fluctuations in the velocity and position of the test particle are calculated. Our results show that the Brownian motion in the direction normal to the plates is reinforced in comparison to that in the single plate case. The effective temperature associated with this normal Brownian motion could be three times as large as that in the single plate case. However, the negative dispersions for the velocity and position in the longitudinal directions, which could be interpreted as reducing the quantum uncertainties of the particle, acquire positive corrections due to the presence of the second plate, and are thus weakened.

  13. Brownian motion of a charged test particle in vacuum between two conducting plates

    CERN Document Server

    Yu, H; Yu, Hongwei; Chen, Jun

    2004-01-01

    The Brownian motion of a charged test particle caused by quantum electromagnetic vacuum fluctuations between two perfectly conducting plates is examined and the mean squared fluctuations in the velocity and position of the test particle are calculated. Our results show that the Brownian motion in the direction normal to the plates is reinforced in comparison to that in the single-plate case. The effective temperature associated with this normal Brownian motion could be three times as large as that in the single-plate case. However, the negative dispersions for the velocity and position in the longitudinal directions, which could be interpreted as reducing the quantum uncertainties of the particle, acquire positive corrections due to the presence of the second plate, and are thus weakened.

  14. Thickness Evaluation of Aluminium Plate Using Pulsed Eddy Current Technique

    Science.gov (United States)

    Singh, Gurpartap; Bapat, Harsh Madhukar; Singh, Bhanu Pratap; Bandyopadhyay, Manojit; Puri, Rakesh Kumar; Badodkar, Deepak Narayanrao

    2013-10-01

    This paper describes a pulsed eddy current (PEC) based non-destructive testing system used for detection of thickness variation in aluminium plate. A giant magneto-resistive sensor has been used instead of pick up coil for detecting resultant magnetic field. The PEC response signals obtained from 1 to 5 mm thickness change in aluminium plate were investigated. Two time domain features, namely peak value and time to peak, of PEC response were used for extracting information about thickness variation in aluminium plate. The variation of peak value and time to peak with thickness was compared. A program was developed to display the thickness variation of the tested sample.

  15. Incipient Motion of Sediment Under Currents

    Institute of Scientific and Technical Information of China (English)

    DOU Guoren

    2000-01-01

    Summarized in the paper are the author′s studies on incipient motion of sediment in recent 40years. In addition to the forces of gravity, drag and lift, the cohesive force and the additional static pressure are important for fine particles. The relations between three stages of incipient motion are defined by use of instantaneous velocity. Formulas for initial velocity and critical shear stress are given and overall verified by the author′s and others′ experimental data

  16. Controlling the motion of multiple objects on a Chladni plate

    National Research Council Canada - National Science Library

    Zhou, Quan; Sariola, Veikko; Latifi, Kourosh; Liimatainen, Ville

    2016-01-01

    The origin of the idea of moving objects by acoustic vibration can be traced back to 1787, when Ernst Chladni reported the first detailed studies on the aggregation of sand onto nodal lines of a vibrating plate...

  17. Numerical Wave Flume Study on Wave Motion Around Submerged Plates

    Institute of Scientific and Technical Information of China (English)

    齐鹏; 侯一筠

    2003-01-01

    Nonlinear interaction between surface waves and a submerged horizontal plate is investigated in the absorbed numerical wave flume developed based on the volume of fluid (VOF) method. The governing equations of the numerical model are the continuity equation and the Reynolds-Averaged Navier-Stokes (RANS) equations with the k-ε turbulence equations. Incident waves are generated by an absorbing wave-maker that eliminates the waves reflected from structures. Results are obtained for a range of parameters, with consideration of the condition under which the reflection coefficient becomes maximal and the transmission coefficient minimal. Wave breaking over the plate, vortex shedding downwave, and pulsating flow below the plate are observed. Time-averaged hydrodynamic force reveals a negative drift force. All these characteristics provide a reference for construction of submerged plate breakwaters.

  18. Supercontinent Pangea, Mantle Dynamics, and Reference Frame of Global Plate Motions

    Science.gov (United States)

    Zhong, S.; Rudolph, M. L.; Liu, X.

    2014-12-01

    Arguably the most important and challenging goal in geodynamics is to understand the two-way dynamics between tectonic plates and mantle convection. While it has long been recognized that the present-day degree-2 mantle structure as imaged seismically is closely related to the plate motions (Hager and O'Connell, 1981) and their history (500 Ma (Torsvik et al., 2014), although its statistical significance has been challenged (Austermann et al., 2013). The proposals of the spatially stable Africa and Pacific LLSVPs and of the LIP eruptions along their edges have also been exploited in attempts to build global plate motion models since the Pangea assembly by providing a plate motion reference frame or inferring true polar wander (TPW) corrections to the plate motions (Torsvik et al., 2014). Second, mantle dynamics studies indicate that degree-1 mantle convection, which is expected with realistic lithospheric and mantle viscosity, may be needed for assembly of a supercontinent (e.g., Pangea) (Zhong et al., 2007). This suggests that the present degree-2 mantle structure may have been formed only after the Pangea assembly from an initially degree-1 structure - a scenario that is consistent with convection calculations with a proxy plate motion model that considers Pangea process (Zhang et al., 2010). In this presentation, in addition to critically reviewing these arguments, we will discuss calculations of long-wavelength geoid for the mantle with thermochemical piles and LLSVPs and their potential effects on TPW determinations and hence reconstruction of plate motion (i.e., net lithospheric rotation). We will also present additional calculations of mantle structure evolution using different plate motion history models.

  19. Global tectonics and the plate motion obtained from the ITRF97 station velocity vectors

    Institute of Scientific and Technical Information of China (English)

    MA; Zongjin(马宗晋); REN; Jinwei(任金卫); ZHANG; Jin(张进)

    2003-01-01

    By studying the characteristics of current crustal motion by using the ITRF97 station velocity vectors, it has been found that the ITRF97 station velocity vectors are coherent with those of NUVEL-1A model. Both the ITRF97 and NUVEL-1A velocity vectors show that the northern hemisphere is moving towards northeast and northwest along the North Atlantic Ridge. The Eurasian plate is moving to northeast, east, and southeast. The North American continent is moving to northwest, west, and southwest. The movement in the southern hemisphere is different completely.The movements of African, South American and Indian-Australian plates almost all direct to NE-NNE. The three plates take the South Atlantic Ridge and the Indian Ridge as boundaries, and the movement vectors increase gradually, showing a "lag" type stretch movement as the result of the superimposition of the whole movement of the southern hemisphere and the spreading of ocean ridges. The difference of velocity fields between the northern and southern hemispheres is obvious, and there is a disharmony zone between the two hemispheres. The geological data show that there is an oblique and discontinuous shear zone between the two hemispheres. Along this shear zone, eight large earthquakes (Ms≥7.8) took place from August 1999 to January 2001, while in the same time period, the seismic activities along the western and southern Pacific subduction zone is low, showing the significance of the shear zone on the global scale. The results in this paper indicate the relative shear motion between the northern and southern hemispheres.

  20. First general solutions for unidirectional motions of rate type fluids over an infinite plate

    Directory of Open Access Journals (Sweden)

    Constantin Fetecau

    2015-09-01

    Full Text Available Based on a simple but important remark regarding the governing equation for the non-trivial shear stress corresponding to the motion of a fluid over an infinite plate, exact solutions are established for the motion of Oldroyd-B fluids due to the plate that applies an arbitrary time-dependent shear stress to the fluid. These solutions, that allow us to provide the first exact solutions for motions of rate type fluids produced by an infinite plate that applies constant, constantly accelerating or oscillating shears stresses to the fluid, can easily be reduced to the similar solutions for Maxwell, second grade or Newtonian fluids performing the same motion. Furthermore, the obtained solutions are used to develop general solutions for the motion induced by a moving plate and to correct or recover as special cases different known results from the existing literature. Consequently, the motion problem of such fluids over an infinite plate that is moving in its plane or applies a shear stress to the fluid is completely solved.

  1. Contemporary plate motions from Lageos - A decade later

    Science.gov (United States)

    Christodoulidis, D. C.; Smith, D. E.; Klosko, S. M.; Dunn, P. J.; Robbins, J. W.

    1986-01-01

    Progress made due to Lageos tracking and the participation of over 20 countries in the acquisition and analysis of precise range measurements is reviewed. Results of both the observed global and regional plate kinematics are presented. Mission accomplishments include the following: (1) laser technology advancements of more than an order of magnitude in single point range precision over the last ten years, (2) station positioning at the few centimeter accuracy level for annual solutions, and (3) the emergence of a global picture of plate kinematics.

  2. The coupling of mechanical dynamics and induced currents in plates and surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Weissenburger, D.W.; Bialek, J.M.

    1986-10-01

    Significant mechanical reactions and deflections may be produced when electrical eddy currents induced in a conducting structure by transformer-like electromotive forces interact with background magnetic fields. Additional eddy currents induced by structural motion through the background fields modify both the mechanical and electrical dynamic behavior of the system. The observed effects of these motional eddy currents are sometimes referred to as magnetic damping and magnetic stiffness. This paper addresses the coupled structural deformation and eddy currents in flat plates and simple two-dimensional surfaces in three-space. A coupled system of equations has been formulated using finite element techniques for the mechanical aspects and a mesh network method for the electrical aspects of the problem.

  3. Super-weak asthenosphere models in light of plate motions and azimuthal anisotropy

    Science.gov (United States)

    Becker, T. W.

    2016-12-01

    Plate motions and azimuthal seismic anisotropy from surface waves are consistent with a strong, oceanic lithosphere that is predominantly dragged by slabs, and weakened upon subduction. Plates are underlain and sustained by a moderately weak asthenosphere, as expected from the temperature and pressure dependence of olivine viscosity for the upper mantle. However, recent observations from active source seismology, magneto-tellurics, body wave anisotropy, and postseismic surface deformation can be interpreted to imply the existence of a very weak channel of low viscosity material, potentially decoupling plates, not unlike a plume-fed asthenosphere scenario in several ways. Here, I explore the implications of such a decoupling channel for plate driving forces as well as observations of seismic anisotropy. The thickness and viscosity reduction of the channel are expected to trade off with each other, and plate motions are sensitive to the lateral extent of this super-weak asthenosphere. While there is some ambiguity of plate motion metrics with the strength of slabs, seismic anisotropy is expected to be sensitive to how shear is localized with depth. The overall good fit of azimuthal anisotropy patterns to flow model predictions brakes down for a number of the more extreme lateral and depth-dependent viscosity scenarios. This may imply that weakening mechanisms may not apply globally under plates, but are rather limited to isolated regions, perhaps associated with melt rich pockets that have limited connectivity.

  4. Relative Motion between the Rivera and North American Plates: Constraints from Focal Mechanisms

    Science.gov (United States)

    Suárez, Gerardo; Jaramillo, Said H.; Bandy, William

    2010-05-01

    The direction and velocity of the Rivera Plate in western Mexico relative to the North American plate has been a source of controversy. The southeastern segment of this plate boundary has been the site of one of the largest subduction events observed in Mexico during the last 100 years: the 3 June 1932 earthquake (Mw 8.2). To the northwest of the rupture zone of the 1932 event, however, there are no other known large subduction events, either from the historical or instrumental record. We analyze all focal mechanisms in this northern segment of the plate boundary to define the direction of relative motion between these two plates. The largest event occurred beneath the Tres Marias Escarpment, the earthquake of 4 December 1948. The recomputed magnitude yields Mw 6.4. This event caused widespread damage in a penal colony on the Tres Marias Islands. Although the focal mechanism of the 1948 event is not well constrained, the first arrival data collected shows reverse faulting with P axes oriented in a NE-SW direction. This mechanism coincides with other two fault plane solutions of more recent events. These mechanisms indicate reverse faulting beneath the Tres Marias Escarpment. To the northwest of the Islas Marias, in area where no clear physiographic feature defines the plate limits, we identify a group of strike-slip events, where the E-W trending nodal plane indicates right-lateral motion. These mechanisms suggest that the relative motion between Rivera and North America may be taken up by right-lateral strike slip motion. The accuracy of the locations does not allow to define in detail the geometry of this plate boundary. The slip vectors determined from these focal mechanisms are compared with the flow lines resulting from the various poles of relative motion between Rivera and North America to constrain its location.

  5. A new plate motions model for the central Atlantic region

    Science.gov (United States)

    Tassi, L.; Schettino, A.

    2010-12-01

    Although the plate kinematics associated with the opening of the central Atlantic ocean after the break-up of Pangaea has been the subject of several studies since the late 1960s, there are still open problems and debated solutions to the tectonic evolution of this area. In particular, the initial fit of Pangaea, the spreading directions during the early stages of opening, the existence of ridge jumps, and the entity of deformation processes in northwest Africa are still subject to different interpretations by distinct research groups. We performed a reassessment of the central Atlantic plate kinematics since the early Jurassic through a re-examination of marine magnetic anomalies and fracture zone trends. A total of 432 ship tracks from the NGDC GEODAS database for the time interval from 1964 through 1994 in the area comprised between the Fifteen-Twenty FZ and the Azores triple junction were analyzed. The data quality was assessed through the examination of Kp indices, and 191 magnetic profiles were extracted having an azimuth that differed from the fracture zones trend by less than 30° and did not cross any fracture zone. Magnetic data collected during moderately disturbed days (Kp > 5) were also filtered away. The 191 ship track segments were projected onto flow lines that parallel existing fracture zones in order to avoid shape distortion of the magnetic anomalies. Finally, the magnetic data were high-pass filtered to remove trends. A new advanced software tool for the analysis and interpretation of the anomalies was developed in order to improve the reliability of magnetic anomaly identifications. The main result of this work is a new map of the magnetic lineations in the central Atlantic, which overcomes the flaws of previous maps. The structural pattern that results from this study evidences that: 1) a unique spreading direction existed during the early and middle Jurassic, and until the M25 - M21 time interval in the late Jurassic. Such a spreading

  6. Current status and future research in motion planning

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Y.K.

    1995-07-01

    There have been numerous research efforts in the field of motion planning, resulting in many theoretical and practical results. We review the current status of existing motion planning algorithms, evaluate their completeness and efficiencies on modern computers, and suggest fruitful future research directions.

  7. Counter-current motion in counter-current chromatography.

    Science.gov (United States)

    Ito, Yoichiro

    2014-12-12

    After the CCC2012 meeting, I have received an e-mail regarding the terminology of "Countercurrent Chromatography". It stated that the term "Countercurrent" is a misnomer, because its stationary phase is motionless in the column and that the method should be renamed as liquid-liquid separations or centrifugal separations. However, it was found that these names are already used for various other techniques as found via Google search. The term "Countercurrent Chromatography" was originally made after two preparative methods of Countercurrent distribution and liquid Chromatography, both having no countercurrent motion in the column. However, it is surprising to find that this F1 hybrid method "Countercurrent Chromatography" can clearly exhibit countercurrent motion within the separation column in both hydrodynamic and hydrostatic equilibrium systems. This justifies that "Countercurrent Chromatography" is a proper term for this chromatographic method. Published by Elsevier B.V.

  8. The effects of possibly buoyant flat slab segments on Nazca and South American plate motions

    Science.gov (United States)

    Lithgow-Bertelloni, C. R.; Shea, R.; Crameri, F.

    2014-12-01

    Flat slabs are ubiquitous today and in Earth's past, present in at least 10% of present-day subduction zones. The Nazca slab is a classic example with large dip variations along strike, including two prominent flat segments in Peru and Argentina that coincide with the subduction of aseismic ridges. The origin of flat segments remain enigmatic though much work has examined the consequences for upper plate deformation and continued subduction. In the case of the Argentinian flat segment, detailed seismic imaging has shown significantly increased crustal thickness in the flat part of the slab. Our present understanding of oceanic crust formation suggests that incrased crustal thickness forms in response to larger degrees of partial melt, which in turn decrease the water content of the formed crust. The residuum from this process is depleted. The resulting combined lithospheric column is buoyant with respect to the underlying mantle, and likely cold from its contact with the overlying plate and unlikely to undergo the basalt-eclogite transition due to kinetic hindrances. This has consequences for mantle flow and the shear stresses it exerts at the base of the lithosphere and hence to plate motions. Interestingly, the motion of the Nazca-South America pair is difficult to reproduce even in the most sophisticated models (Stadler et al. 2010) without invoking special coupling, rheology or forces. We examine the effects of the subduction of neutral and buoyant flat segments on mantle flow and plate motions, globally and locally for Nazca and South America. We construct high-resolution models of the morphology and density structure of the Nazca slab and embed them in an existing global slab model. We compute the global viscous flow induced and predict plate motions consistent with the density heterogeneity and plate geometry. As an end member we also examine a Nazca slab that dips uniformly with a 30 degree dip. We find, perhaps unsurprisingly, that the most important

  9. Impact of uncertain reference-frame motions in plate kinematic reconstructions: A theoretical appraisal

    Science.gov (United States)

    Iaffaldano, Giampiero; Stein, Seth

    2017-01-01

    Geoscientists infer past plate motions, which serve as fundamental constraints for a range of studies, from observations of magnetic isochrons as well as hotspots tracks on the ocean floor and, for stages older than the Cretaceous, from paleomagnetic data. These observations effectively represent time-integrals of past plate motions but, because they are made at present, yield plate kinematics naturally tied to a present-day reference-frame, which may be another plate or a hotspots system. These kinematics are therefore different than those occurred at the time when the rocks acquired their magnetisation or when hotspot-related marine volcanism took place, and are normally corrected for the reference-frame absolute motion (RFAM) that occurred since then. The impact of true-polar-wander events on paleomagnetic data and the challenge of inferring hotspot drifts result in RFAMs being less resolved - in a temporal sense - and prone to noise. This limitation is commonly perceived to hamper the correction of plate kinematic reconstructions for RFAMs, but the extent to which this may be the case has not been explored. Here we assess the impact of uncertain RFAMs on kinematic reconstructions using synthetic models of plate motions over 100 million years. We use randomly-drawn models for the kinematics of two plates separated by a spreading ridge to generate a synthetic magnetisation pattern of the ocean floor. The kinematics we infer from such a pattern are outputs that we correct for synthetic RFAMs using two equivalent methods (a classical one as well as another that we propose and test here) and then compare to the 'true' motions input. We assess the misfits between true and inferred kinematics by exploring a statistically-significant number of models where we systematically downgrade the temporal resolution of RFAM synthetic data and add noise to them. We show that even poorly-resolved, noisy RFAMs are sufficient to retrieve reliable plate kinematic reconstructions

  10. Anatomy of the Dead Sea transform: Does it reflect continuous changes in plate motion?

    Science.gov (United States)

    ten Brink, U.S.; Rybakov, M.; Al-Zoubi, A. S.; Hassouneh, M.; Frieslander, U.; Batayneh, A.T.; Goldschmidt, V.; Daoud, M.N.; Rotstein, Y.; Hall, J.K.

    1999-01-01

    A new gravity map of the southern half of the Dead Sea transform offers the first regional view of the anatomy of this plate boundary. Interpreted together with auxiliary seismic and well data, the map reveals a string of subsurface basins of widely varying size, shape, and depth along the plate boundary and relatively short (25-55 km) and discontinuous fault segments. We argue that this structure is a result of continuous small changes in relative plate motion. However, several segments must have ruptured simultaneously to produce the inferred maximum magnitude of historical earthquakes.

  11. Global plate tectonics and the secular motion of the pole

    Science.gov (United States)

    Soler, T.

    1977-01-01

    Astronomical data compiled during the last 70 years by the international organizations providing the coordinates of the instantaneous pole clearly shows a persistent drift of the mean pole. The differential contributions to the earth's second-order tensor of inertia were obtained and applied, resulting in no significant displacement of the earth's principal axis. In view of the above, the effect that theoretical geophysical models for absolute plate velocities may have on an apparent displacement of the mean pole as a consequence of station drifting was analyzed. The investigation also reports new values for the crustal tensor of inertia (assuming an ellipsoidal earth) and the orientation of its axis of figure, reopening the old speculation of a possible sliding of the whole crustover the upper mantle, including the supporting geophysical and astronomic evidence.

  12. Inverse problem of pulsed eddy current field of ferromagnetic plates

    Science.gov (United States)

    Chen, Xing-Le; Lei, Yin-Zhao

    2015-03-01

    To determine the wall thickness, conductivity and permeability of a ferromagnetic plate, an inverse problem is established with measured values and calculated values of time-domain induced voltage in pulsed eddy current testing on the plate. From time-domain analytical expressions of the partial derivatives of induced voltage with respect to parameters, it is deduced that the partial derivatives are approximately linearly dependent. Then the constraints of these parameters are obtained by solving a partial linear differential equation. It is indicated that only the product of conductivity and wall thickness, and the product of relative permeability and wall thickness can be determined accurately through the inverse problem with time-domain induced voltage. In the practical testing, supposing the conductivity of the ferromagnetic plate under test is a fixed value, and then the relative variation of wall thickness between two testing points can be calculated via the ratio of the corresponding inversion results of the product of conductivity and wall thickness. Finally, this method for wall thickness measurement is verified by the experiment results of a carbon steel plate. Project supported by the National Defense Basic Technology Research Program of China (Grant No. Z132013T001).

  13. Motion of current filaments in avalanching PIN diodes

    Science.gov (United States)

    Xingrong, Ren; Changchun, Chai; Zhenyang, Ma; Yintang, Yang; Liping, Qiao; Chunlei, Shi; Lihua, Ren

    2013-04-01

    The motion of current filaments in avalanching PIN diodes has been investigated in this paper by 2D transient numerical simulations. The simulation results show that the filament can move along the length of the PIN diode back and forth when the self-heating effect is considered. The voltage waveform varies periodically due to the motion of the filament. The filament motion is driven by the temperature gradient in the filament due to the negative temperature dependence of the impact ionization rates. Contrary to the traditional understanding that current filamentation is a potential cause of thermal destruction, it is shown in this paper that the thermally-driven motion of current filaments leads to the homogenization of temperature in the diode and is expected to have a positive influence on the failure threshold of the PIN diode.

  14. Present-day plate motions: Retrieval from the TOPEX/Poseidon orbitography network (DORIS system)

    Science.gov (United States)

    Souriau, Annie; Cazenave, Anny; Biancale, R.; Balmino, G.; Dominh, K.; Mazzega, P.; Lemoine, J.-M.; Boucher, Claude; Willis, P.; Kasser, M.

    1991-01-01

    The goal of the proposal is to determine the present motion of the main tectonic plates from the Doppler data of the Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) orbitography system, which includes in its final configuration about 50 tracking stations with a world-wide distribution.

  15. High-resolution reconstructions of Pacific-North America plate motion: 20 Ma to present

    Science.gov (United States)

    DeMets, C.; Merkouriev, S.

    2016-11-01

    We present new rotations that describe the relative positions and velocities of the Pacific and North America plates at 22 times during the past 19.7 Myr, offering ≈1-Myr temporal resolution for studies of the geotectonic evolution of western North America and other plate boundary locations. Derived from ≈18 000 magnetic reversal, fracture zone and transform fault identifications from the Pacific-Antarctic-Nubia-North America plate circuit and the velocities of 935 GPS sites on the Pacific and North America plates, the new rotations and GPS-derived angular velocity indicate that the rate of motion between the two plates increased by ≈70 per cent from 19.7 to 9±1 Ma, but changed by less than 2 per cent since 8 Ma and even less since 4.2 Ma. The rotations further suggest that the relative plate direction has rotated clockwise for most of the past 20 Myr, with a possible hiatus from 9 to 5 Ma. This conflicts with previously reported evidence for a significant clockwise change in the plate direction at ≈8-6 Ma. Our new rotations indicate that Pacific plate motion became obliquely convergent with respect to the San Andreas Fault of central California at 5.2-4.2 Ma, in agreement with geological evidence for a Pliocene onset of folding and faulting in central California. Our reconstruction of the northern Gulf of California at 6.3 Ma differs by only 15-30 km from structurally derived reconstructions after including 3-4 km Myr-1 of geodetically measured slip between the Baja California Peninsula and Pacific plate. This implies an approximate 15-30 km upper bound for plate non-rigidity integrated around the global circuit at 6.3 Ma. A much larger 200±54 km discrepancy between our reconstruction of the northern Gulf of California at 12 Ma and that estimated from structural and marine geophysical observations suggests that faults in northwestern Mexico or possibly west of the Baja California Peninsula accommodated large amounts of obliquely divergent dextral shear

  16. Earthquake stress drops, ambient tectonic stresses and stresses that drive plate motions

    Science.gov (United States)

    Hanks, T.C.

    1977-01-01

    A variety of geophysical observations suggests that the upper portion of the lithosphere, herein referred to as the elastic plate, has long-term material properties and frictional strength significantly greater than the lower lithosphere. If the average frictional stress along the non-ridge margin of the elastic plate is of the order of a kilobar, as suggested by the many observations of the frictional strength of rocks at mid-crustal conditions of pressure and temperature, the only viable mechanism for driving the motion of the elastic plate is a basal shear stress of several tens of bars. Kilobars of tectonic stress are then an ambient, steady condition of the earth's crust and uppermost mantle. The approximate equality of the basal shear stress and the average crustal earthquake stress drop, the localization of strain release for major plate margin earthquakes, and the rough equivalence of plate margin slip rates and gross plate motion rates suggest that the stress drops of major plate margin earthquakes are controlled by the elastic release of the basal shear stress in the vicinity of the plate margin, despite the existence of kilobars of tectonic stress existing across vertical planes parallel to the plate margin. If the stress differences available to be released at the time of faulting are distributed in a random, white fasbion with a mean-square value determined by the average earthquake stress drop, the frequency of occurrence of constant stress drop earthquakes will be proportional to reciprocal faulting area, in accordance with empirically known frequency of occurrence statistics. ?? 1977 Birkha??user Verlag.

  17. The MAO NASU Plate Archive Database. Current Status and Perspectives

    Science.gov (United States)

    Pakuliak, L. K.; Sergeeva, T. P.

    2006-04-01

    The preliminary online version of the database of the MAO NASU plate archive is constructed on the basis of the relational database management system MySQL and permits an easy supplement of database with new collections of astronegatives, provides a high flexibility in constructing SQL-queries for data search optimization, PHP Basic Authorization protected access to administrative interface and wide range of search parameters. The current status of the database will be reported and the brief description of the search engine and means of the database integrity support will be given. Methods and means of the data verification and tasks for the further development will be discussed.

  18. Toward a self-consistent, high-resolution absolute plate motion model for the Pacific

    Science.gov (United States)

    Wessel, Paul; Harada, Yasushi; Kroenke, Loren W.

    2006-03-01

    The hot spot hypothesis postulates that linear volcanic trails form as lithospheric plates move relative to stationary or slowly moving plumes. Given geometry and ages from several trails, one can reconstruct absolute plate motions (APM) that provide valuable information about past and present tectonism, paleogeography, and volcanism. Most APM models have been designed by fitting small circles to coeval volcanic chain segments and determining stage rotation poles, opening angles, and time intervals. Unlike relative plate motion (RPM) models, such APM models suffer from oversimplicity, self-inconsistencies, inadequate fits to data, and lack of rigorous uncertainty estimates; in addition, they work only for fixed hot spots. Newer methods are now available that overcome many of these limitations. We present a technique that provides high-resolution APM models derived from stationary or moving hot spots (given prescribed paths). The simplest model assumes stationary hot spots, and an example of such a model is presented. Observations of geometry and chronology on the Pacific plate appear well explained by this type of model. Because it is a one-plate model, it does not discriminate between hot spot drift or true polar wander as explanations for inferred paleolatitudes from the Emperor chain. Whether there was significant relative motion within the hot spots under the Pacific plate during the last ˜70 m.y. is difficult to quantify, given the paucity and geological uncertainty of age determinations. Evidence in support of plume drift appears limited to the period before the 47 Ma Hawaii-Emperor Bend and, apart from the direct paleolatitude determinations, may have been somewhat exaggerated.

  19. Entropy generation in the flow system generated in between two parallel plates due to bivertical motion of the top plate

    Indian Academy of Sciences (India)

    Ahmet Z Sahin; Bekir S Yilbas

    2009-06-01

    Thermodynamic irreversibility in the flow system provides information on the energy and power losses in the system. Minimization of entropy generation in the flow system enables for the parametric optimization of the system operation. In the present study, parallel plates, in between, filled with the fluid are considered. The fluid motion resulted from the bi-vertical compression of the top plate of the parallel plates is examined. The entropy generation rate in the flow system is formulated after considering the constant movement of the top plate, constant applied load, and the combination of the constant velocity and applied load to the top plate. The optimum operating conditions related to the fluid motion in between the parallel plates is determined through the entropy analysis. It is found that the combination of the constant velocity and the constant applied load resulted in the low entropy generation rate.

  20. Experimental Study on Current-Driven Domain Wall Motion

    Science.gov (United States)

    Ono, T.; Yamaguchi, A.; Tanigawa, H.; Yano, K.; Kasai, S.

    2006-06-01

    Current-driven domain wall (DW) motion for a well-defined single DW in a micro-fabricated magnetic wire with submicron width was investigated by real-space observation with magnetic force microscopy. Magnetic force microscopy visualizes that a single DW introduced in a wire is displaced back and forth by positive and negative pulsed-current, respectively. Effect of the Joule heating, reduction of the threshold current density by shape control, and magnetic ratchet effect are also presented.

  1. Absolute plate motion of Africa around Hawaii-Emperor bend time

    Science.gov (United States)

    Maher, S. M.; Wessel, P.; Müller, R. D.; Williams, S. E.; Harada, Y.

    2015-06-01

    Numerous regional plate reorganizations and the coeval ages of the Hawaiian Emperor bend (HEB) and Louisville bend of 50-47 Ma have been interpreted as a possible global tectonic plate reorganization at ˜chron 21 (47.9 Ma). Yet for a truly global event we would expect a contemporaneous change in Africa absolute plate motion (APM) reflected by physical evidence distributed on the Africa Plate. This evidence has been postulated to take the form of the Réunion-Mascarene bend which exhibits many HEB-like features, such as a large angular change close to ˜chron 21. However, the Réunion hotspot trail has recently been interpreted as a sequence of continental fragments with incidental hotspot volcanism. Here we show that the alternative Réunion-Mascarene Plateau trail can also satisfy the age progressions and geometry of other hotspot trails on the Africa Plate. The implied motion, suggesting a pivoting of Africa from 67 to 50 Ma, could explain the apparent bifurcation of the Tristan hotspot chain, the age reversals seen along the Walvis Ridge, the sharp curve of the Canary trail, and the diffuse nature of the St. Helena chain. To test this hypothesis further we made a new Africa APM model that extends back to ˜80 Ma using a modified version of the Hybrid Polygonal Finite Rotation Method. This method uses seamount chains and their associated hotspots as geometric constraints for the model, and seamount age dates to determine APM through time. While this model successfully explains many of the volcanic features, it implies an unrealistically fast global lithospheric net rotation, as well as improbable APM trajectories for many other plates, including the Americas, Eurasia and Australia. We contrast this speculative model with a more conventional model in which the Mascarene Plateau is excluded in favour of the Chagos-Laccadive Ridge rotated into the Africa reference frame. This second model implies more realistic net lithospheric rotation and far-field APMs, but

  2. Is a 50 Ma Event Recorded in the Absolute Plate Motion of Africa?

    Science.gov (United States)

    Maher, S. M.; Wessel, P.; Müller, R.; Harada, Y.

    2012-12-01

    There is considerable evidence for a global plate tectonic reorganization at ~Chron 21, as suggested by observed changes in global relative plate motion (RPM). The timings of these events appear to coincide with the age of the Hawaiian Emperor Bend (HEB), i.e., ~47-50 Ma. This 120° bend has traditionally been the poster child for the fixed hotspot hypothesis, suggesting the Pacific plate underwent a change in absolute plate motion (APM) as it moved over a more or less stationary Hawaiian hotspot. However, palaeomagnetic evidence favors southward motion of the Hawaii hotspot during the Emperor stage, limiting the amount of APM change required. In the Indo-Atlantic realm, RPMs involving Africa all seem compatible with a change in Africa APM around ~50 Ma. If this global plate reorganization took place there should also be physical evidence on the Africa plate itself due to the change in Africa APM. A candidate for such evidence may be the Réunion-Mascarene bend, which exhibits many HEB-like features. However, the Réunion hotspot also created the Chagos-Laccadive ridge as it encountered (and later crossed) the Carlsberg Ridge, and the oldest Mascarene section closest to the Seychelles may be continental in origin; thus there is some uncertainty in how to interpret the geometry. Furthermore, published APM models have had difficulty modeling this abrupt change in orientation. To reexamine this problem we derived a new Africa APM model that goes back to ~65 Ma using the Hybrid Polygonal Finite Rotation Method. The modeling incorporates the geometry and ages of seamount chains on the Africa plate and their associated hotspots as suitable constraints on an Africa APM model. The present as well as earlier positions of hotspots can be adjusted to get the best fit for the model. We examine how models with or without a ~50 Ma bend satisfy the geometries and age progressions of hotspot chains on the Africa plate and how well the predictions match observed paleolatitudes.

  3. Reconciling geodetic and geologic estimates of recent plate motion across the Southwest Indian Ridge

    Science.gov (United States)

    DeMets, C.; Calais, E.; Merkouriev, S.

    2016-10-01

    We use recently published, high-resolution reconstructions of the Southwest Indian Ridge to test whether a previously described systematic difference between Global Positioning System (GPS) and 3.16-Myr-average estimates of seafloor spreading rates between Antarctica and Africa is evidence for a recent slowdown in Southwest Indian Ridge seafloor spreading rates. Along the Nubia-Antarctic segment of the ridge, seafloor opening rates that are estimated with the new, high-resolution reconstructions and corrected for outward displacement agree well with geodetic rate estimates and reduce previously reported, highly significant non-closure of the Nubia-Antarctic-Sur plate circuit. The observations are inconsistent with a slowdown in spreading rates and instead indicate that Nubia-Antarctic plate motion has been steady since at least 5.2 Ma. Lwandle-Antarctic seafloor spreading rates that are estimated from the new high-resolution reconstructions differ insignificantly from a GPS estimate, thereby implying steady Lwandle-Antarctic plate motion since 5.2 Ma. Between the Somalia and Antarctic plates, the new Southwest Indian Ridge reconstructions eliminate roughly half of the systematic difference between the GPS and MORVEL spreading rate estimates. We interpret the available observations as evidence that Somalia-Antarctic spreading rates have been steady since at least 5.2 Ma and postulate that the remaining difference is attributable to random and/or systematic errors in the plate kinematic estimates and the combined effects of insufficient geodetic sampling of undeforming areas of the Somalia plate, glacial isostatic adjustment in Antarctica, and transient deformation triggered by the 1998 Mw=8.2 Antarctic earthquake, the 2004 Mw=9.3 Sumatra earthquake, or possibly other large historic earthquakes.

  4. The interpretation of crustal dynamics data in terms of plate motions and regional deformation near plate boundaries

    Science.gov (United States)

    Solomon, Sean C.

    During our participation in the NASA Crustal Dynamics Project under NASA contract NAS-27339 and grant NAG5-814 for the period 1982-1991, we published or submitted for publication 30 research papers and 52 abstracts of presentations at scientific meetings. In addition, five M.I.T. Ph.D. students (Eric Bergman, Steven Bratt, Dan Davis, Jeanne Sauber, Anne Sheehan) were supported wholly or in part by this project during their thesis research. Highlights of our research progress during this period include the following: application of geodetic data to determine rates of strain in the Mojave block and in central California and to clarify the relation of such strain to the San Andreas fault and Pacific-North American plate motions; application of geodetic data to infer post seismic deformation associated with large earthquakes in the Imperial Valley, Hebgen Lake, Argentina, and Chile; determination of the state of stress in oceanic lithosphere from a systematic study of the centroid depths and source mechanisms of oceanic intraplate earthquakes; development of models for the state of stress in young oceanic regions arising from the differential cooling of the lithosphere; determination of the depth extent and rupture characteristics of oceanic transform earthquakes; improved determination of earthquake slip vectors in the Gulf of California, an important data set for the estimation of Pacific-North American plate motions; development of models for the state of stress and mechanics of fold-and-thrust belts and accretionary wedges; development of procedures to invert geoid height, residual bathymetry, and differential body wave travel time residuals for lateral variations in the characteristic temperature and bulk composition of the oceanic upper mantle; and initial GPS measurements of crustal deformation associated with the Imperial-Cerro Prieto fault system in southern California and northern Mexico. Full descriptions of the research conducted on these topics may be

  5. Kinematics of the Ethiopian Rift and Absolute motion of Africa and Somalia Plates

    Science.gov (United States)

    Muluneh, A. A.; Cuffaro, M.; Doglioni, C.

    2013-12-01

    The Ethiopian Rift (ER), in the northern part of East African Rift System (EARS), forms a boundary zone accommodating differential motion between Africa and Somalia Plates. Its orientation was influenced by the inherited Pan-African collisional system and related lithospheric fabric. We present the kinematics of ER derived from compilation of geodetic velocities, focal mechanism inversions, structural data analysis, and construction of geological profiles. GPS velocity field shows a systematic eastward magnitude increase in NE direction in the central ER. In the same region, incremental extensional strain axes recorded by earthquake focal mechanism and fault slip inversion show ≈N1000E orientation. This deviation between GPS velocity trajectories and orientation of incremental extensional strain is developed due to left lateral transtensional deformation. This interpretation is consistent with the en-échelon pattern of tensional and transtensional faults, the distribution of the volcanic centers, and the asymmetry of the rift itself. Small amount of vertical axis blocks rotation, sinistral strike slip faults and dyke intrusions in the rift accommodate the transtensional deformation. We analyzed the kinematics of ER relative to Deep and Shallow Hot Spot Reference Frames (HSRF). Comparison between the two reference frames shows different kinematics in ER and also Africa and Somalia plate motion both in magnitude and direction. Plate spreading direction in shallow HSRF (i.e. the source of the plumes locates in the asthenosphere) and the trend of ER deviate by about 27°. Shearing and extension across the plate boundary zone contribute both to the style of deformation and overall kinematics in the rift. We conclude that the observed long wavelength kinematics and tectonics are consequences of faster SW ward motion of Africa than Somalia in the shallow HSRF. This reference frame seems more consistent with the geophysical and geological constraints in the Rift. The

  6. Global Plate Motions and Their Impact on the Earth's Surface Area Change

    Institute of Scientific and Technical Information of China (English)

    Cao Shuai; Zhang Keliang; Wei Dongping

    2010-01-01

    Based on their Euler polea,we calculated the relative velocities between every two plates in the typical global plate motion models,respectively,and estimated the area change along these boundaries.In our calculations.plates on both sides accommodated area changes depending on the boundary types:extensional,convergent or transform,so we can estimate area change of each plate and then globally.Our preliminary results show that the area of the southern hemisphere increased while that of the northern hemisphere decreased over the past 1 million years,and global area has increased by 26,000km2 to 36,000km2,which corresponds to the 160m~250m increment on the Earth's radius if all these area increments are attributed to Earth's expansion.Taking the NUVEL-1 model as an example,of the 14 plates in this model,11 are decreasing,but the global area has increased because of the larger increment amount from Africa,North America and Antarctica.Finally,we also discussed factors affecting the global area change such as subduction zone retreating and back-arc spreading.

  7. High-resolution estimates of Southwest Indian Ridge plate motions, 20 Ma to present

    Science.gov (United States)

    DeMets, C.; Merkouriev, S.; Sauter, D.

    2015-12-01

    We present the first estimates of Southwest Indian Ridge (SWIR) plate motions at high temporal resolution during the Quaternary and Neogene based on nearly 5000 crossings of 21 magnetic reversals out to C6no (19.72 Ma) and the digitized traces of 17 fracture zones and transform faults. Our reconstructions of this slow-spreading mid-ocean ridge reveal several unexpected results with notable implications for regional and global plate reconstructions since 20 Ma. Extrapolations of seafloor opening distances to zero-age seafloor based on reconstructions of reversals C1n (0.78 Ma) through C3n.4 (5.2 Ma) reveal evidence for surprisingly large outward displacement of 5 ± 1 km west of 32°E, where motion between the Nubia and Antarctic plates occurs, but 2 ± 1 km east of 32°E, more typical of most mid-ocean ridges. Newly estimated SWIR seafloor spreading rates are up to 15 per cent slower everywhere along the ridge than previous estimates. Reconstructions of the numerous observations for times back to 11 Ma confirm the existence of the hypothesized Lwandle plate at high confidence level and indicate that the Lwandle plate's western and eastern boundaries respectively intersect the ridge near the Andrew Bain transform fault complex at 32°E and between ˜45°E and 52°E, in accord with previous results. The Nubia-Antarctic, Lwandle-Antarctic and Somalia-Antarctic rotation sequences that best fit many magnetic reversal, fracture zone and transform fault crossings define previously unknown changes in the Neogene motions of all three plate pairs, consisting of ˜20 per cent slowdowns in their spreading rates at 7.2^{+0.9 }_{ -1.4} Ma if we enforce a simultaneous change in motion everywhere along the SWIR and gradual 3°-7° anticlockwise rotations of the relative slip directions. We apply trans-dimensional Bayesian analysis to our noisy, best-fitting rotation sequences in order to estimate less-noisy rotation sequences suitable for use in future global plate reconstructions

  8. Discovering plate boundaries: Laboratory and classroom exercises using geodetic data to develop students' understanding of plate motion

    Science.gov (United States)

    Olds, S. E.

    2010-12-01

    To introduce the concept of plate boundaries, typical introductory geology exercises include students observing and plotting the location of earthquakes and volcanoes on a map to visually demarcate plate boundaries. Accompanying these exercises, students are often exposed to animations depicting the movement of Earth’s tectonic plates over time. Both of these teaching techniques are very useful for describing where the tectonics plates have been in the past, their shapes, and where the plates are now. With the integration of data from current geodetic techniques such as GPS, InSAR, LiDAR, students can learn that not only have the tectonic plates moved in the past, but they are moving, deforming, and changing shape right now. Additionally, GPS data can be visualized using time scales of days to weeks and on the scale of millimeters to centimeters per year. The familiar temporal and spatial scales of GPS data also help students understand that plate tectonics is a process that is happening in the present and can ease the transition to thinking about processes that are typically described using deep time, a very difficult concept for students to grasp. To provide a more robust learning environment, UNAVCO has been incorporating high-precision GPS data into free, place-based, data-rich learning modules for educators and students in introductory Earth science courses at secondary and undergraduate levels. These modules integrate new scientific discoveries related to crustal deformation and explore applications of GPS, LiDAR, and InSAR techniques to research. They also provide students with case studies highlighting the process of scientific discovery, providing context and meaning. Concurrent to these efforts, tools to visualize the inter-relationships of geophysical and geologic processes, structures, and measurements including high-precision GPS velocity data are an essential part of the learning materials. Among the suite of visualization tools that UNAVCO has made

  9. The benefits of extended plate motion history in mantle circulation models

    Science.gov (United States)

    Webb, Peter; Davies, Huw; Davies, Rhodri; Hochard, Cyril; Stampfli, Gerard

    2010-05-01

    Mantle Circulation Models (MCMs) are mantle convection simulations conditioned with plate motion history. Due to difficulties in reconstructing plate motions beyond ≈ 120 Ma, MCMs often only incorporate the most recent 120 Myr of plate tectonic evolution. We find that such models are strongly influenced by initial conditions. The development of a new series of tectonic reconstructions extending back to the Triassic (230 Ma) and including careful reconstruction of the oceanic parts of the plates (modified from Stampfli and Borel, 2004, Stampfli et al. 2008 and references therein) should prove to be of huge importance to MCMs. In this study we present a comparison between the traditionally used 120 Myr and the latest 230 Myr plate motion histories. We use the three-dimensional spherical mantle convection code TERRA (Bunge et al., 2003) to simulate convection at Earth like vigour. Here we apply the plate motion history as a surface velocity boundary condition to drive the internal convection of an already well-mixed system. The forward models from a chosen starting point to present day yield information on mantle temperature (as well as pressure, velocity and material properties) throughout the volume. One of the ways to validate our results is to compare these with tomographic models. Seismic tomography provides us with a snapshot of Earth's mantle at present day. Assuming that the mantle is driven largely by thermal convection, we can assume that the seismically fast regions are associated with cooler, denser material. The most significant of these can be interpreted as remnants of subducted slabs (Hafkenscheid et al 2006, van der Meer et al. 2010). We convert the temperatures predicted by the MCM to seismic velocities using the latest techniques (e.g. Cobden et al., 2008) and compare the calculated velocities to a range of seismic tomography models (both P and S wave). This way we can examine the validity of the surface velocity boundary condition and identify

  10. Evaluation of motion platform embedded with dual belt treadmill instrumented with two force plates.

    Science.gov (United States)

    Sinitski, Emily H; Lemaire, Edward D; Baddour, Natalie

    2015-01-01

    Motek Medical's Computer Aided Rehabilitation Environment (CAREN)-Extended system is a virtual environment primarily used in physical rehabilitation and biomechanical research. This virtual environment consists of a 180 degree projection screen used to display a virtual scene, a 12-camera motion capture system, and a six degree of freedom actuated platform equipped with a dual-belt treadmill and two force plates. The goal of this article was to investigate the performance characteristics associated with a "treadmill-motion platform" configuration and how system operation can affect the data collected. Platform static and dynamic characteristics were evaluated by translating or rotating the platform over progressively larger distances and comparing input and measured values. Treadmill belt speed was assessed with and without a person walking on the platform and at different orientations. Force plate measurements were examined when the treadmill was in operation, during ambulation, and over time to observe the baseline drift. Platform acceleration was dependent on the distance travelled and system settings. Treadmill speed variability was greatest at faster speeds. Force plate measurements were affected by platform and treadmill operation, contralateral impact forces during gait, and baseline drift. Knowledge of performance characteristics and their effect on outcome data is crucial for effective design of CAREN research protocols and rehabilitation scenarios.

  11. Determination of the tectonic plate motion by satellite laser ranging in 1999-2003

    Science.gov (United States)

    Schillak, S.; Wnuk, E.

    The paper presents results of the tectonic plates motion determination from satellite laser ranging in the period 1999-2003 The SLR station velocities were calculated from station geocentric coordinates determined from one month orbital arcs of Lageos-1 and Lageos-2 satellites for the first day of each arc The mean orbital RMS-of-fit for 5 years was equal to 15 mm The station velocities were determined for 29 stations and points in 1999-2003 it means for all SLR stations with data time span longer than 20 months The accuracy of station velocities determination varied from 0 4 mm year to 3 mm year dependent on quality of data and data span The difference of station velocities between ITRF2000 and the presented results were in the range 0-5 mm year Only for four stations Riyad Maidanak-2 Beijng and Arequipa after earthquake in 2001 the differences were statistically significant For the most stations is a good agreement with the NUVEL1A model of tectonic plates motion The significant differences were detected for stations Arequipa Concepcion Shanghai and Simosato The results differs from the model NUVEL1A in the station velocities and azimuths for South America tectonic plate and Japan

  12. Current-induced domain wall motion in ferromagnetic semiconductors

    Science.gov (United States)

    Ohno, Hideo

    2007-03-01

    Low magnetization (˜0.05 T) and high spin-polarization in ferromagnetism of transition metal-doped GaAs allow us to explore a number of spin-dependent phenomena not readily accessible in metal ferromagnets. Spin-polarized current induced domain wall (DW) motion in (Ga,Mn)As [1, 2] reveals rich physics resulting from the interaction between spin-polarized electrons and localized spins inside a magnetic DW. By using a 30 nm thick (Ga,Mn)As layer (xMn = 0.045) with perpendicular magnetic anisotropy, we have measured by magneto-optical Kerr microscopy a wide range of velocity-current density curves in the sample temperature range of 97 -- 107 K. Two regimes are found in the current density dependence of the DW velocity. At high-current densities (> 2 x 10^5 A/cm^2), the domain wall velocity is approximately a linear function of the current density above a threshold current density. This result will be compared to the recent theories of DW motion. At low-current densities, the functional form of the velocity-current curves follow an empirical scaling law, obtained by modifying the one for magnetic-field induced creep. This shows that current-induced DW creep is present. We have also determined the intrinsic resistance of the DW in a similar configuration [3]. *M. Yamanouchi, D. Chiba, F. Matsukura, and H. Ohno, Nature 428, 539 (2004). *M. Yamanouchi, D. Chiba, F. Matsukura, T. Dietl and H. Ohno, Phys. Rev. Lett. 96, 096601 (2006). *D. Chiba, M. Yamanouchi, F. Matsukura, T. Dietl, and H. Ohno, Phys. Rev. Lett. 96, 096602 (2006).

  13. Plate tectonics and planetary habitability: current status and future challenges.

    Science.gov (United States)

    Korenaga, Jun

    2012-07-01

    Plate tectonics is one of the major factors affecting the potential habitability of a terrestrial planet. The physics of plate tectonics is, however, still far from being complete, leading to considerable uncertainty when discussing planetary habitability. Here, I summarize recent developments on the evolution of plate tectonics on Earth, which suggest a radically new view on Earth dynamics: convection in the mantle has been speeding up despite its secular cooling, and the operation of plate tectonics has been facilitated throughout Earth's history by the gradual subduction of water into an initially dry mantle. The role of plate tectonics in planetary habitability through its influence on atmospheric evolution is still difficult to quantify, and, to this end, it will be vital to better understand a coupled core-mantle-atmosphere system in the context of solar system evolution. © 2012 New York Academy of Sciences.

  14. Intraplate deformation, stress in the lithosphere and the driving mechanism for plate motions

    Science.gov (United States)

    Albee, Arden L.

    1993-01-01

    The initial research proposed was to use the predictions of geodynamical models of mantle flow, combined with geodetic observations of intraplate strain and stress, to better constrain mantle convection and the driving mechanism for plate motions and deformation. It is only now that geodetic observations of intraplate strain are becoming sufficiently well resolved to make them useful for substantial geodynamical inference to be made. A model of flow in the mantle that explains almost 90 percent of the variance in the observed longwavelength nonhydrostatic geoid was developed.

  15. Numerical simulation of tectonic plates motion and seismic process in Central Asia

    Energy Technology Data Exchange (ETDEWEB)

    Peryshkin, A. Yu., E-mail: alexb700@yandex.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Makarov, P. V., E-mail: bacardi@ispms.ru; Eremin, M. O., E-mail: bacardi@ispms.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055, Russia and National Research Tomsk State University, Tomsk, 634050 (Russian Federation)

    2014-11-14

    An evolutionary approach proposed in [1, 2] combining the achievements of traditional macroscopic theory of solid mechanics and basic ideas of nonlinear dynamics is applied in a numerical simulation of present-day tectonic plates motion and seismic process in Central Asia. Relative values of strength parameters of rigid blocks with respect to the soft zones were characterized by the δ parameter that was varied in the numerical experiments within δ = 1.1–1.8 for different groups of the zonal-block divisibility. In general, the numerical simulations of tectonic block motion and accompanying seismic process in the model geomedium indicate that the numerical solutions of the solid mechanics equations characterize its deformation as a typical behavior of a nonlinear dynamic system under conditions of self-organized criticality.

  16. Shrinking of the Cocos and Nazca Plates due to Horizontal Thermal Contraction and Implications for Plate Non-rigidity and the Non-closure of the Pacific-Cocos-Nazca Plate Motion Circuit

    Science.gov (United States)

    Gordon, R. G.; Kreemer, C.

    2015-12-01

    Plate rigidity is the central tenet of plate tectonics. Mounting evidence suggests, however, that significant intraplate deformation occurs in oceanic lithosphere due to horizontal thermal contraction, the rate of which decreases as ≈ 1/age [Kumar & Gordon 2009]. Support for this hypothesis comes from the azimuths of submarine transform faults, which are fit significantly better assuming shrinking plates than by assuming rigid plates [Mishra & Gordon 2015]. Previously we estimated the intraplate velocity field of the Pacific plate accounting for horizontal thermal contraction. The ≈2 mm/yr southeastward motion predicted for the northeastern part of the plate relative to the Pacific-Antarctic Rise may contribute to the non-closure of the Pacific-North America plate motion circuit. In a reference frame in which fix the oldest portion of the Pacific plate, some sites on the plate move up to ≈2 mm/yr [Kreemer & Gordon 2014]. Here we present intraplate velocity fields of the Cocos and Nazca plates and discuss their implications for the non-rigidity of plates and the non-closure of the Pacific-Cocos-Nazca plate circuit, which fails closure by a stunning 14 ±5 mm/yr [DeMets et al. 2010]. If we fix the oldest part of the Cocos plate, intraplate velocities of up to ≈2 mm/yr are estimated, with the fastest motion occurring at the northern end of the plate. If we fix the oldest part of the Nazca plate, displacement rates up to 2 mm/yr are estimated, with the fastest motion occurring in the northeasternmost portion of the plate. In the velocity fields for both plates, the lithosphere adjacent to transform faults along the East Pacific Rise tends to move to the south, which would skew the azimuths of the transform faults clockwise of the values expected for rigid plates, which is the same as the sense of misfit between observed azimuths of transform faults and the azimuths calculated from the MORVEL global set of relative angular velocities [DeMets et al. 2010]. Direct

  17. A revised estimate of Pacific-North America motion and implications for Western North America plate boundary zone tectonics

    Science.gov (United States)

    Demets, Charles; Gordon, Richard G.; Stein, Seth; Argus, Donald F.

    1987-01-01

    Marine magnetic profiles from the Gulf of Californa are studied in order to revise the estimate of Pacific-North America motion. It is found that since 3 Ma spreading has averaged 48 mm/yr, consistent with a new global plate motion model derived without any data. The present data suggest that strike-slip motion on faults west of the San Andreas is less than previously thought, reducing the San Andreas discrepancy with geodetic, seismological, and other geologic observations.

  18. The World Stress Map Database Release 2016 - Global Crustal Stress Pattern vs. Absolute Plate Motion

    Science.gov (United States)

    Heidbach, Oliver; Rajabi, Mojtaba; Ziegler, Moritz; Reiter, Karsten

    2016-04-01

    The World Stress Map (WSM) Project was initiated in 1986 under the auspices of the International Lithosphere Program in order to compile the global information on the contemporary crustal stress state. The data come from a wide range of stress indicators such as borehole data (e.g. hydraulic fracturing, borehole breakouts), earthquake focal mechanism solutions, engineering methods (e.g. overcoring), and geological data (e.g. inversion of fault slip measurements). To guarantee the comparability of the different data sources each data record is assessed with the WSM quality ranking scheme. For the 30th anniversary we compiled a new WSM database with 42,410 data records which is an increase by >20,000 data records compared to the WSM 2008 database. In particular we added new data from more than 3,500 deep boreholes and put special emphasis on regions which previously had sparse or no published stress data such as China, Australia, Brazil, Southern Africa, Middle East and Iceland. Furthermore, we fully integrated the Chinese stress database and the Australian stress database. The resulting data increase reveals several areas with regional and local variability of the stress pattern. In particular we re-visited the question whether the plate boundary forces are the key control of the plate-wide stress pattern as indicated by the first release of the WSM in 1989 [Zoback et al, 1989]. As the WSM has now more than 10 times data records and thus a better spatial coverage we first filter the long-wave length stress pattern on a regular grid. We determine at these grid points the difference between absolute plate motion azimuth using the global plate model HS3-NUVEL1A [Gripp and Gordon, 2002] and the mean orientation of the maximum horizontal stress. The preliminary results show that the earlier findings are still valid in principal. However, all plates show in some parts significant deviations from this general trend; some plates such as the Australian Plate show hardly any

  19. Coupling Motion and Energy Harvesting of Two Side-by-Side Flexible Plates in a 3D Uniform Flow

    Directory of Open Access Journals (Sweden)

    Dibo Dong

    2016-05-01

    Full Text Available The fluid-structure interaction problems of two side-by-side flexible plates with a finite aspect ratio in a three-dimensional (3D uniform flow are numerically studied. The plates’ motions are entirely passive under the force of surrounding fluid. By changing the aspect ratio and transverse distance, the coupling motions, drag force and energy capture performance are analyzed. The mechanisms underlying the plates’ motion and flow characteristics are discussed systematically. The adopted algorithm is verified and validated by the simulation of flow past a square flexible plate. The results show that the plate’s passive flapping behavior contains transverse and spanwise deformation, and the flapping amplitude is proportional to the aspect ratio. In the side-by-side configuration, three distinct coupling modes of the plates’ motion are identified, including single-plate mode, symmetrical flapping mode and decoupled mode. The plate with a lower aspect ratio may suffer less drag force and capture less bending energy than in the isolated situation. The optimized selection for obtaining higher energy conversion efficiency is the plate flapping in single-plate mode, especially the plate with a higher aspect ratio. The findings of this work provide several new physical insights into the understanding of fish schooling and are expected to inspire the developments of underwater robots or energy harvesters.

  20. Current-controlled unidirectional edge-meron motion

    Science.gov (United States)

    Xing, Xiangjun; Pong, Philip W. T.; Zhou, Yan

    2016-11-01

    In order to address many of the challenges and bottlenecks currently experienced by traditional charge-based technologies, various alternatives are being actively explored to provide potential solutions of device miniaturization and scaling in the post-Moore's-law era. Amongst these alternatives, spintronic physics and devices have recently attracted rapidly increasing interest by exploiting the additional degree of electrons-spin. For example, magnetic domain-wall racetrack-memory and logic devices have been realized via manipulating domain-wall motion. As compared to domain-wall-based devices, magnetic skyrmions have the advantages of ultrasmall size (typically 5-100 nm in diameter), facile current-driven motion, topological stability, and peculiar emergent electrodynamics, promising for next-generation electronics applications in the post-Moore's-law regime. Here, a magnetic meron device, which behaves similarly to a PN-junction diode, is demonstrated for the first time, by tailoring the current-controlled unidirectional motion of edge-merons (i.e., fractional skyrmions) in a nanotrack with interfacial Dzyaloshinskii-Moriya interaction. The working principles of the meron device, theoretically predicted from the Thiele equation for topological magnetic objects, are further verified using micromagnetic simulations. The present study has revealed the topology-independent transport property of different magnetic objects and is expected to open the vista toward integrated composite circuitry (with unified data storage and processing) based on a single magnetic chip, as the meron device can be used, either as a building block to develop complex logic components or as a signal controller to interconnect skyrmion, domain-wall, and even spin-wave devices.

  1. Current-induced domain wall motion in nanoscale ferromagnetic elements

    Energy Technology Data Exchange (ETDEWEB)

    Malinowski, G [Laboratoire de Physique des Solides, CNRS, Universite Paris-sud 11, 91405 Orsay Cedex (France); Boulle, O [SPINTEC, CEA/CNRS/UJF/GINP, INAC, 38054 Grenoble Cedex 9 (France); Klaeui, M, E-mail: Klaeui@uni-mainz.de [SwissFEL, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Laboratory of Nanomagnetism and Spin Dynamics, Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne (Switzerland)

    2011-09-28

    We review the details of domain wall (DW) propagation due to spin-polarized currents that could potentially be used in magnetic data storage devices based on domains and DWs. We discuss briefly the basics of the underlying spin torque effect and show how the two torques arising from the interaction between the spin-polarized charge carriers and the magnetization lead to complex dynamics of a spin texture such as a DW. By direct imaging we show how confined DWs in nanowires can be displaced using currents in in-plane soft-magnetic materials, and that when using short pulses, fast velocities can be attained. For high-anisotropy out-of-plane magnetized wires with narrow DWs we present approaches to deducing the torque terms and show that in these materials potentially more efficient domain wall motion could be achieved.

  2. Past Plate Motions and The Evolution of Earth's Lower Mantle: Relating LLSVPs and Plume Distribution

    Science.gov (United States)

    Bull, A. L.; Torsvik, T. H.; Shephard, G. E.

    2015-12-01

    Seismic tomography elucidates broad, low shear-wave velocity structures in the lower mantle beneath Africa and the central Pacific with uncertain physical and compositional origins. The anomalously slow areas, which cover nearly 50% of the core-mantle boundary, are often referred to as Large Low Shear Velocity Provinces (LLSVPs) due to the reduced velocity of seismic waves passing through them. Several hypotheses have arisen to explain the LLSVPs in the context of large-scale mantle convection. One end-member scenario infers a spatial correlation between LLSVP margins at depth and the reconstructed surface eruption sites of hotspots, kimberlites, and Large Igneous Provinces. Such a correlation has been explained by the preferential triggering of plumes at LLSVP margins by impingement of the subducting lithosphere upon the lower thermal boundary layer at the interface between ambient mantle and the higher density structures. This scenario propounds that Earth's plate motion history plays a controlling role in plume development, and that the location, geometry and morphology of plumes may be influenced by the movement of subducting slabs. Here, we investigate what is necessary to create such a pattern of plume distribution in relation to LLSVPs. We consider what effect past plate motions may have had on the evolution of Earth's lower mantle, and discuss the development of mantle plumes in terms of subduction dynamics. We integrate plate tectonic histories and numerical models of mantle convection to investigate the role that subduction history plays in the development and evolution of plumes in the presence of LLSVPs. To test whether an interaction exists between the surface location of subduction and plume eruption sites, and if so, to what degree over time, we apply varying shifts to the absolute reference frame of the plate reconstruction. With this method, we are able to change the location of subduction at the surface and thus the global flow field. This in turn

  3. Late Neogene changes in North America and Antarctica absolute plate motions inferred from the Mid-Atlantic and Southwest Indian Ridges spreading histories

    Science.gov (United States)

    Iaffaldano, G.; DeMets, C.

    2016-08-01

    Reconstructions of absolute plate motions underpin our understanding of the plate torque balance, but are challenging due to difficulties in inferring well-dated rates and directions of plate movements from hot spot tracks. Useful information about plate dynamics can be inferred from rapid absolute plate motion changes, as these are linked only to the torque(s) that changed. Here we infer late Neogene changes in the absolute motions of North America and possibly Antarctica from changes in the easier-to-determine relative plate motions recorded along the Arctic, northern Mid-Atlantic and Southwest Indian Ridges. We show that Eurasia/North America and Nubia/North America motions changed by the same amount between 8 and 5 Ma, as may have Nubia/Antarctica and Somalia/Antarctica plate motions. By considering additional, independent constraints on Somalia/India plate motion, we argue that a scenario in which North America and Antarctica absolute motions changed is the simplest one that explains the observed changes in relative motions. We speculate that these changes are linked to the late Neogene dynamics of the Pacific plate.

  4. MagicPlate-512: A 2D silicon detector array for quality assurance of stereotactic motion adaptive radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Petasecca, M., E-mail: marcop@uow.edu.au; Newall, M. K.; Aldosari, A. H.; Fuduli, I.; Espinoza, A. A.; Porumb, C. S.; Guatelli, S.; Metcalfe, P.; Lerch, M. L. F.; Rosenfeld, A. B. [Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2500, Australia and Illawarra Health Medical Research Institute, Wollongong, NSW 2522 (Australia); Booth, J. T.; Colvill, E. [School of Medicine, University of Sydney, Sydney, NSW 2006, Australia and Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, NSW 2065 (Australia); Duncan, M.; Cammarano, D. [Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2500 (Australia); Carolan, M. [Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2500 (Australia); Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, NSW 2500 (Australia); Illawarra Health Medical Research Institute, Wollongong, NSW 2522 (Australia); Oborn, B. [Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW 2500 (Australia); Illawarra Cancer Care Centre, Wollongong Hospital, Wollongong, NSW 2500 (Australia); Perevertaylo, V. [SPA-BIT, Kiev 02232 (Ukraine); Keall, P. J. [School of Medicine, University of Sydney, Sydney, NSW 2006 (Australia)

    2015-06-15

    Purpose: Spatial and temporal resolutions are two of the most important features for quality assurance instrumentation of motion adaptive radiotherapy modalities. The goal of this work is to characterize the performance of the 2D high spatial resolution monolithic silicon diode array named “MagicPlate-512” for quality assurance of stereotactic body radiation therapy (SBRT) and stereotactic radiosurgery (SRS) combined with a dynamic multileaf collimator (MLC) tracking technique for motion compensation. Methods: MagicPlate-512 is used in combination with the movable platform HexaMotion and a research version of radiofrequency tracking system Calypso driving MLC tracking software. The authors reconstruct 2D dose distributions of small field square beams in three modalities: in static conditions, mimicking the temporal movement pattern of a lung tumor and tracking the moving target while the MLC compensates almost instantaneously for the tumor displacement. Use of Calypso in combination with MagicPlate-512 requires a proper radiofrequency interference shielding. Impact of the shielding on dosimetry has been simulated by GEANT4 and verified experimentally. Temporal and spatial resolutions of the dosimetry system allow also for accurate verification of segments of complex stereotactic radiotherapy plans with identification of the instant and location where a certain dose is delivered. This feature allows for retrospective temporal reconstruction of the delivery process and easy identification of error in the tracking or the multileaf collimator driving systems. A sliding MLC wedge combined with the lung motion pattern has been measured. The ability of the MagicPlate-512 (MP512) in 2D dose mapping in all three modes of operation was benchmarked by EBT3 film. Results: Full width at half maximum and penumbra of the moving and stationary dose profiles measured by EBT3 film and MagicPlate-512 confirm that motion has a significant impact on the dose distribution. Motion

  5. Astrometry with "Carte du Ciel" plates, San Fernando zone. II. CdC-SF: a precise proper motion catalogue

    CERN Document Server

    Vicente, Belen; Garzon, Francisco; Girard, Terrence M

    2009-01-01

    The historic plates of the "Carte du Ciel", an international cooperative project launched in 1887, offer valuable first-epoch material for the determination of absolute proper motions. We present the CdC-SF, an astrometric catalogue of positions and proper motions derived from the "Carte du Ciel" plates of the San Fernando zone, photographic material with a mean epoch of 1901.4 and a limiting magnitude of V~16, covering the declination range of -10deg < declination < -2deg. Digitization has been made using a conventional flatbed scanner. Special techniques have been developed to handle the combination of plate material and the large distortion introduced by the scanner. The equatorial coordinates are on the ICRS defined by Tycho-2, and proper motions are derived using UCAC2 as second-epoch positions. The result is a catalogue with positions and proper motions for 560000 stars, covering 1080 degrees squared. The mean positional uncertainty is 0.20" (0.12" for well-measured stars) and the proper-motion un...

  6. The Effect of Plate Motion History on the Longevity of Deep Mantle Heterogeneities

    Science.gov (United States)

    Bull, Abigail; Domeier, Mathew; Torsvik, Trond

    2014-05-01

    Numerical studies of mantle convection have attempted to explain tomographic observations that reveal a lower mantle dominated by broad regional areas of lower-than-average shear-wave speeds beneath Africa and the Central Pacific. The anomalous regions, termed LLSVPs ("large low shear velocity provinces"), are inferred to be thermochemical structures encircled by regions of higher-than-average shear-wave speeds associated with Mesozoic and Cenozoic subduction zones. The origin and long-term evolution of the LLSVPs remains enigmatic. It has been proposed that the LLSVP beneath Africa was not present before 240 Ma, prior to which time the lower mantle was dominated by a degree-1 convection pattern with a major upwelling centred close to the present-day Pacific LLSVP and subduction concentrated mainly in the antipodal hemisphere. The African LLSVP would thus have formed during the time-frame of the supercontinent Pangea as a result of return flow in the mantle due to circum-Pacific subduction. An opposing hypothesis, which propounds a more long-term stability for both the African and Pacific LLSVPs, is suggested by recent palaeomagnetic plate motion models that propose a geographic correlation between the surface eruption sites of Phanerozoic kimberlites, major hotspots and Large Igneous Provinces to deep regions of the mantle termed "Plume Generation Zones" (PGZs), which lie at the margins of the LLSVPs. If the surface volcanism was sourced from the PGZs, such a link would suggest that both LLSVPs may have remained stationary for at least the age of the volcanics. i.e., 540 Myr. To investigate these competing hypotheses for the evolution of LLSVPs in Earth's mantle, we integrate plate tectonic histories and numerical models of mantle dynamics and perform a series of 3D spherical thermochemical convection calculations with Earth-like boundary conditions. We improve upon previous studies by employing a new, TPW-corrected global plate motion model to impose surface

  7. Plate kinematics, slab shape and back-arc stress: A comparison between laboratory models and current subduction zones

    Science.gov (United States)

    Heuret, A.; Funiciello, F.; Faccenna, C.; Lallemand, S.

    2007-04-01

    A combination of statistical studies on present-day subduction zones and three-dimensional (3D) laboratory models is performed with the aim to clarify the way that plate kinematics control the geometry of the slab and the overriding plate deformation in subduction zones. In 3D laboratory models, the analogue of a two layer linearly viscous lithosphere-upper mantle system is achieved by means of silicon putty glucose syrup tank experiment. The subducting and overriding plate velocities are systematically changed by exploring the variability field of natural plate kinematics. Both statistical and modelling approaches recognize the importance of overriding plate motion on subduction process behavior: (1) trenches migrate at a rate close to the overriding plate motion, but always move slower than the overriding plates. The mechanism at work is a direct consequence of "slab anchoring" opposed by both lithosphere and mantle viscous resistance and is responsible for overriding plate deformation and slab geometry variability. (2) An overriding plate shortens when the overriding plate moves toward the trench and conditions that are favourable for overriding plate extension are created when the overriding plate moves away from the trench. (3) Shallow and steep dips are found if the overriding plate moves toward and away from the trench, respectively.

  8. Flyer-Plate-Based Current Diagnostic for Magnetized Liner Inertial Fusion Experiments

    Science.gov (United States)

    Reneker, Joseph; Gomez, Matthew; Hess, Mark; Jennings, Christopher

    2015-11-01

    Accurate measurements of the current delivered to Magnetized Liner Inertial Fusion (MagLIF) loads on the Z machine are important for understanding the dynamics of liner implosions. Difficulty acquiring a reliable load current measurement with the standard Z load B-dots has spurred the development of alternative load current diagnostics. Velocimetry of an electromagnetically-accelerated flyer plate can be used to infer the drive current on a flyer surface. A load current diagnostic design is proposed using a cylindrical flyer plate in series with the MagLIF target. Aspects of the flyer plate design were optimized using magnetohydrodynamic simulations. Design and preliminary results will be presented. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  9. Magma production rate along the Ninetyeast Ridge and its relationship to Indian plate motion and Kerguelen hot spot activity

    Science.gov (United States)

    Sreejith, K. M.; Krishna, K. S.

    2015-02-01

    The Ninetyeast Ridge, a linear trace of the Kerguelen hot spot in the Indian Ocean, was emplaced on a rapidly drifting Indian plate. Magma production rates along the ridge track are computed using gravity-derived excess crustal thickness data. The production rates change between 2 and 15 m3/s over timescales of 3-16 Myr. Major variations in magma production rates are primarily associated with significant changes in the Indian plate velocity with low-production phases linked to high plate velocity periods. The lowest magma production rate (2 m3/s) at 62 Ma is associated with the rapid northward drift of Indian plate under the influence of the Reunion mantle plume. The contemporaneous slowing of the African plate coincides with increase in magma production rate along the Walvis Ridge in the Atlantic Ocean. The present study suggests that variations in the Indian plate motion and frequent ridge jumps have a major role in controlling the magma production, particularly on long-period cycles (~16 Myr). Short-period variations (~5 Myr) in magma productions may be associated with intrinsic changes in the plume, possibly due to the presence of solitary waves in the plume conduit.

  10. Theoretical and Experimental Study of the Primary Current Distribution in Parallel-Plate Electrochemical Reactors

    Science.gov (United States)

    Vazquez Aranda, Armando I.; Henquin, Eduardo R.; Torres, Israel Rodriguez; Bisang, Jose M.

    2012-01-01

    A laboratory experiment is described to determine the primary current distribution in parallel-plate electrochemical reactors. The electrolyte is simulated by conductive paper and the electrodes are segmented to measure the current distribution. Experiments are reported with the electrolyte confined to the interelectrode gap, where the current…

  11. NNR constraint in ITRF2000 and the new global plate motion model NNR-ITRF2000VEL

    Institute of Scientific and Technical Information of China (English)

    ZHU; Wenyao; (朱文耀); FU; Yang; (符; 养); LI; Yan; (李; 彦); WU; Xianbing; (吴显兵)

    2003-01-01

    There are 54 sites employed by ITRF2000 for ITRF2000 orientation. The deficiencies are obvious. First, these sites cannot well represent the rotation rate of the earth crust because there is no selected site in five out of fourteen tectonic plates and three of fourteen plates only have one site each. Second, the total angular momentum of the crust is non-vanishing in ITRF2000, even though it is declared that No Net Rotation (NNR) with respect to NNR-NUVEL1A is imposed on ITRF2000 construction according to the documentations of ITRF2000. So the NNR condition in conventional terrestrial reference system (CTRS) realization cannot be satisfied in ITRF2000. In this paper, the criteria of site selection for estimating the Euler vectors are suggested; the Tisserand system constraint equation in ITRF construction is derived; and as a product, the global plate motions can be obtained from the ITRF2000 construction.

  12. Evidence for relative motions between the Indian and Australian Plates during the last 20 m.y. from plate tectonic reconstructions: Implications for the deformation of the Indo-Australian Plate

    Science.gov (United States)

    Royer, Jean-Yves; Chang, Ted

    1991-07-01

    We use plate tectonic reconstructions to establish whether motions between India and Australia occurred since chron 18 (43 Ma). We test the Africa/Antarctica/Australia/India plate circuit closure at chrons 5 (10 Ma), 6 (21 Ma) and 13 (36 Ma) using a compilation of magnetic anomalies and fracture zone traces from the Southeast, Southwest, Central Indian and the Carlsberg ridges. Additional reconstructions at chrons 23 (55 Ma) and 26 (61 Ma) are used to estimate the overall motion between India and Australia. Relative motions between the Indian and Australian plates are estimated using the plate circuit India → Africa → Australia. A new statistical approach, based on spherical regression analyses, is used to assess the uncertainty of the "best-fitting" finite rotations from the uncertainties in the data. The uncertainty in a rotation is described by a covariance matrix directly related to the geometry of the reconstructed plate boundary, to the distribution and estimated errors of the data points along it. Our parameterization of the rotations allows for simple combination of the rotation uncertainties along a plate circuit path. Results for chron 5 are remarkably consistent with present-day kinematics in the Indian Ocean, except that the Arabian and Indian plates are found to be separate plates. Comparisons of the motions between the Indian and African plates across the Carlsberg Ridge with that between the Australian and African plates across the Central Indian Ridge evidence a significant counterclockwise rotation of the Australian plate relative to the Indian plate about a pole located in the Central Indian Basin. The determinations are consistent for chrons 26, 13, 6 and 5. Determination at chron 23 is different but questionable due to the small number of available data. We propose two alternative solutions that both predict convergence within the Wharton and Central Indian basins and extension in the vicinity of the Chagos-Laccadive Ridge. The first

  13. Changes in Late Cretaceous-Quaternary Caribbean plate motion directions inferred from paleostress measurements from striated fault planes

    Science.gov (United States)

    Batbayar, K.; Mann, P.; Hippolyte, J.

    2013-12-01

    We compiled paleostress analyses from previous research works collected at 591 localities of striated fault planes in rocks ranging in age from Late Cretaceous to Quaternary in the circum-Caribbean and Mexico. The purpose of the study is to quantify a progressive clockwise rotation of the Caribbean plate during its Late Cretaceous to recent subduction of the Proto-Caribbean seaway. Paleostress analysis is based on the assumption that slickenside lineations indicate both the direction and sense of maximum resolved shear stress on that fault plane. We have plotted directions of maximum horizontal stress onto plate tectonic reconstructions of the circum-Caribbean plate boundaries and infer that these directions are proxies for paleo-plate motion directions of the Caribbean plate. Plotting these stress directions onto reconstructions provided a better visualization of the relation of stress directions to blocks at their time of Late Cretaceous to recent deformation. Older, more deformed rocks of Late Cretaceous to Eocene ages yield a greater scatter in derived paleostress directions as these rocks have steeper dips, more pervasive faulting, and were likely affected by large rotations as known from previous paleomagnetic studies of Caribbean plate margins. Despite more scatter in measurements from older rock units, four major events that affected the Caribbean plate and the Great Arc of the Caribbean (GAC) are recognizable from changing orientations of stress directions: 1) Late Cretaceous collision of the GAC with southern Mexico and Colombia is consistent with NE directions of maximum compression in rocks of this age range in southern Mexico and EW directions in Colombia as the GAC approached the Proto-Caribbean seaway; 2) Paleocene-Eocene collision of the GAC with the Bahamas platform in Cuba and Hispaniola and with the South American plate in Venezuela is consistent with CW rotations of stress directions in rocks of these ages in the northern Caribbean and CCW

  14. Electrode fall voltage of arc between deion plates during direct-current interruption period

    Science.gov (United States)

    Yokomizu, Y.; Ueda, Y.; Matsumura, T.; Ichikawa, T.; Niwa, Y.; Sakaguchi, W.

    2017-07-01

    A direct-current low-voltage circuit breaker has an arc chute that consists of a stack of several metallic deion plates. The deion plate is also called a splitter plate. The function of the deion plates is to split the arc into several series short-gap arcs. This phenomenon leads to the emergence of electrode fall voltages in the arc chute, eventually contributing to rise in the total arc-voltage in the circuit breaker and to successful current-interruption. The electrode fall voltage therefore plays an important role for successful current-interruption. The present paper describes the estimation result for the electrode fall voltage {{v}\\text{ele}} of the arc between steel deion plates. The estimation is performed by using a newly devised method. This method utilizes the voltage {{v}\\text{chute}} measured across the arc chute and eventually derives {{v}\\text{ele}} on the basis of the statistics: a correlation coefficient between an arc-column electric-field strength {{E}\\text{col}} and an arc current i. Adopting the devised method enabled us to derive 19 V as {{v}\\text{ele}} . Verification is furthermore made to show the validity of the determined electrode-fall voltage, 19 V.

  15. Analysis of errors induced by λ/4 wave plate in fiber-optic current sensor system

    Institute of Scientific and Technical Information of China (English)

    杨瑞峰

    2008-01-01

    1/4λ wave plate is a key element in the fiber-optic current sensor system. When a retardation error or an orientation error of birefringence axes of 1/4λ wave plate with respect to the hi-bi fiber axes occurs in the 1/4λ wave plate, the sensor system will output a wrong result of the measured current. The contributions of these two errors to the final result of the whole system were studied and the errors functions were deduced by establishing the measurement function of the current sensor system with Jones matrixes of the optical elements. The results show that that the greater the orientation error or the retardation error, the larger the final error, and that these two errors cannot be compensated each other.

  16. Alternating current-assisted on-plate proteolysis for MALDI-TOF MS peptide mapping.

    Science.gov (United States)

    Wang, Sheng; Wei, Bangguo; Yang, Pengyuan; Chen, Gang

    2008-11-01

    In this report, alternating current-assisted on-plate proteolysis has been developed for rapid peptide mapping. Protein solutions containing trypsin were allowed to digest directly on the spots of a stainless steel MALDI plate with the assistance of low-voltage alternating current electricity. Alternating current (AC) was allowed to pass through the protein solutions via the MALDI plate and a platinum disc electrode. The feasibility and performance of the novel proteolysis approach were investigated by the digestion of BSA and cytochrome c (Cyt-c). It was demonstrated that AC substantially enhanced the efficiency of proteolysis and the digestion time was significantly reduced to 5 min. The digests were identified by MALDI-TOF MS with sequence coverages of 42% (BSA) and 77% (Cyt-c) that were comparable to those obtained by using conventional in-solution tryptic digestion. The present proteolysis strategy is simple and efficient, offering great promise for MALDI-TOF MS peptide mapping.

  17. Crustal motion studies in the southwest Pacific: Geodetic measurements of plate convergence in Tonga, Vanuatu and the Solomon Islands

    Science.gov (United States)

    Phillips, David A.

    The southwest Pacific is one of the most tectonically dynamic regions on Earth. This research focused on crustal motion studies in three regions of active Pacific-Australia plate convergence in the southwest Pacific: Tonga, the New Hebrides (Vanuatu) and the Solomons Islands. In Tonga, new and refined velocity estimates based on more than a decade of Global Positioning System (GPS) measurements and advanced analysis techniques are much more accurate than previously reported values. Convergence rates of 80 to 165 mm/yr at the Tonga trench represent the fastest plate motions observed on Earth. For the first time, rotation of the Fiji platform relative to the Australian plate is observed, and anomalous deformation of the Tonga ridge was also detected. In the New Hebrides, a combined GPS dataset with a total time series of more than ten years led to new and refined velocity estimates throughout the island arc. Impingement of large bathymetric features has led to arc fragmentation, and four distinct tectonic segments are identified. The central New Hebrides arc segment is being shoved eastward relative to the rest of the arc as convergence is partitioned between the forearc (Australian plate) and the backarc (North Fiji Basin) boundaries due to impingement of the d'Entrecasteaux Ridge and associated Bougainville seamount. The southern New Hebrides arc converges with the Australian plate more rapidly than predicted due to backarc extension. The first measurements of convergence in the northern and southernmost arc segments were also made. In the Solomon Islands, a four-year GPS time series was used to generate the first geodetic estimates of crustal velocity in the New Georgia Group, with 57--84 mm/yr of Australia-Solomon motion and 19--39 mm/yr of Pacific-Solomon motion being observed. These velocities are 20--40% lower than predicted Australia-Pacific velocities. Two-dimensional dislocation models suggest that most of this discrepancy can be attributed to locking of

  18. Understanding plate-motion changes over the past 100 Myr with quantitative models of the coupled lithosphere/mantle system

    Science.gov (United States)

    Stotz, Ingo; Iaffaldano, Giampiero; Rhodri Davies, D.

    2015-04-01

    The volume of geophysical datasets has grown substantially over recent decades. Our knowledge of continental evolution has increased due to advances in interpreting the records of orogeny and sedimentation. Ocean-floor observations now allow one to resolve past plate motions (e.g. in the North Atlantic and Indian Ocean over the past 20 Myr) at temporal resolutions of about 1 Myr. Altogether, these ever-growing datasets allow us to reconstruct the past evolution of Earth's lithospheric plates in greater detail. This is key to unravelling the dynamics of geological processes, because plate motions and their temporal changes are powerful probe into the evolving force balance between shallow- and deep-rooted processes. However, such progress is not yet matched by the ability to quantitatively model past plate-motion changes and, therefore, to test hypotheses on the dominant controls. The main technical challenge is simulating the rheological behaviour of the lithosphere/mantle system, which varies significantly from viscous to brittle. Traditionally computer models for viscous mantle flow on the one hand, and for the motions of the brittle lithosphere on the other hand, have been developed separately. Coupling of these two independent classes of models has been accomplished only for neo-tectonic scenarios, without accounting for the impact of time-evolving mantle-flow (e.g. Iaffaldano and Bunge 2009). However, we have built a coupled model to simulate the lithosphere/mantle system (using SHELLS and TERRA, respectively) through geological time, and to exploit the growing body of geophysical data as a primary constraint on these quantitative models. TERRA is a global spherical finite-element code for mantle convection (e.g. Baumgardner 1985, Bunge et al. 1996, Davies et al. 2013), whilst SHELLS is a thin-sheet finite-element code for lithosphere dynamics (e.g. Bird 1998). Our efforts are focused, in particular, on achieving the technical ability to: (i) simulate the

  19. Quantifying melt production and degassing rate at mid-ocean ridges from global mantle convection models with plate motion history

    Science.gov (United States)

    Li, Mingming; Black, Benjamin; Zhong, Shijie; Manga, Michael; Rudolph, Maxwell L.; Olson, Peter

    2016-07-01

    The Earth's surface volcanism exerts first-order controls on the composition of the atmosphere and the climate. On Earth, the majority of surface volcanism occurs at mid-ocean ridges. In this study, based on the dependence of melt fraction on temperature, pressure, and composition, we compute melt production and degassing rate at mid-ocean ridges from three-dimensional global mantle convection models with plate motion history as the surface velocity boundary condition. By incorporating melting in global mantle convection models, we connect deep mantle convection to surface volcanism, with deep and shallow mantle processes internally consistent. We compare two methods to compute melt production: a tracer method and an Eulerian method. Our results show that melt production at mid-ocean ridges is mainly controlled by surface plate motion history, and that changes in plate tectonic motion, including plate reorganizations, may lead to significant deviation of melt production from the expected scaling with seafloor production rate. We also find a good correlation between melt production and degassing rate beneath mid-ocean ridges. The calculated global melt production and CO2 degassing rate at mid-ocean ridges varies by as much as a factor of 3 over the past 200 Myr. We show that mid-ocean ridge melt production and degassing rate would be much larger in the Cretaceous, and reached maximum values at ˜150-120 Ma. Our results raise the possibility that warmer climate in the Cretaceous could be due in part to high magmatic productivity and correspondingly high outgassing rates at mid-ocean ridges during that time.

  20. Towards absolute plate motions constrained by lower-mantle slab remnants

    NARCIS (Netherlands)

    Meer, D.G. van der; Spakman, W.; Hinsbergen, D.J.J. van; Amaru, M.L.; Torsvik, T.H.

    2010-01-01

    Since the first reconstruction of the supercontinent Pangaea, key advances in plate tectonic reconstructions have been made1. Although the movement of tectonic plates since the start of the mid-Cretaceous period (~100 million years (Myr) ago) is relatively well understood1, 2, the longitudinal posit

  1. The correlation between geomagnetic field reversals, Hawaiian volcanism, and the motion of the Pacific plate

    Directory of Open Access Journals (Sweden)

    W. Dong

    1996-06-01

    Full Text Available The correlation between geomagnetic field reversals and volcanism is investigated, according to the speculated consequence on volcanoes of the transient electric currents in the geodynamo, through Joule's heating, before and after every reversal event. We evaluate the temporal variation during the last ~ 70 Ma both of the magma emplacement rate Q(t from the Hawaii hot spot, and of the speed v(t of the Pacific plate, by means of the observed volumes of islands and seamounts along the Hawaii/Emperor Seamounts chain, and their respective radiometric datings. Results confirm expectations. A justification of the volcanic crises that lead to the generation of the large igneous provinces during the last ~ 250 Ma also emerged. We describe in detail the complex pattern of the timings of the different effects. Joule's power is generally responsible for ~ 75-80% of magmatism, and friction power only for ~ 20-25%; but, on some occasions almost ~ 100% is fuelled by friction alone. The visco-elastic coupling between lithosphere and asthenosphere results ~ 96% viscous, and ~ 4% elastic.

  2. NUMERICAL ANALYSIS AND EXPERIMENT OF UNSTEADY THERMAL FIELDOF ROTOR PLATE FOR EDDY CURRENT RETARDER

    Institute of Scientific and Technical Information of China (English)

    LIU Chengye; HE Ren

    2008-01-01

    The physical model based on heat transfer theory and virtual boundary method for analyzing unsteady thermal field of rotor plate for eddy current retarder used in automobile is established and boundary conditions are also defined. The finite element governing equation is derived by Galerkin method. The time differential item is discrete based on Galerkin format that is stable at any condition. And a new style of varying time step method is used in iteration process. The thermal field on the rotor plate at the radial and axle directions is analyzed and varying temperature at appointed points on two side-surfaces is measured. The testing and analytical data are uniform approximately. Finite element method can be used for estimating thermal field of the rotor plate at initial design stage of eddy current retarder.

  3. Eddy current heating of irregularly shaped plates by slow ramped fields

    Energy Technology Data Exchange (ETDEWEB)

    Dresner, L.

    1979-09-01

    Eddy current heating of thin conducting plates of various shapes by a perpendicular field is studied, assuming that the magnetic field created by the eddy currents is negligible in comparison with the external field. The method is to introduce the stream function of the eddy currents, which is shown to satisfy Poisson's equation, and then employ a pair of complementary variational principles (i.e., a minimum principle and a maximum principle), the extrema of which equal the eddy current heating. Two such complementary principles give not only an estimate of the eddy current heating, but a bound on the error of the estimate as well.

  4. Next-generation plate-tectonic reconstructions using GPlates

    OpenAIRE

    2011-01-01

    Plate tectonics is the kinematic theory that describes the large-scale motions and events of the outermost shell of the solid Earth in terms of the relative motions and interactions of large, rigid, interlocking fragments of lithosphere called tectonic plates. Plates form and disappear incrementally over time as a result of tectonic processes. There are currently about a dozen major plates on the surface of the Earth, and many minor ones. The present-day configuration of tectonic plates is il...

  5. Pulsed remote field eddy current technique applied to non-magnetic flat conductive plates

    Science.gov (United States)

    Yang, Binfeng; Zhang, Hui; Zhang, Chao; Zhang, Zhanbin

    2013-12-01

    Non-magnetic metal plates are widely used in aviation and industrial applications. The detection of cracks in thick plate structures, such as multilayered structures of aircraft fuselage, has been challenging in nondestructive evaluation societies. The remote field eddy current (RFEC) technique has shown advantages of deep penetration and high sensitivity to deeply buried anomalies. However, the RFEC technique is mainly used to evaluate ferromagnetic tubes. There are many problems that should be fixed before the expansion and application of this technique for the inspection of non-magnetic conductive plates. In this article, the pulsed remote field eddy current (PRFEC) technique for the detection of defects in non-magnetic conducting plates was investigated. First, the principle of the PRFEC technique was analysed, followed by the analysis of the differences between the detection of defects in ferromagnetic and non-magnetic plain structures. Three different models of the PRFEC probe were simulated using ANSYS. The location of the transition zone, defect detection sensitivity and the ability to detect defects in thick plates using three probes were analysed and compared. The simulation results showed that the probe with a ferrite core had the highest detecting ability. The conclusions derived from the simulation study were also validated by conducting experiments.

  6. A new visualization of the motion of the Indian Plate in the Cenozoic

    Science.gov (United States)

    Holmes, J. J.; Stegman, D. R.

    2011-12-01

    90 million years ago the Indian Plate detached from the ancient supercontinent Gondwana and diverged away from the Antarctic and African plates in a northwest-wards direction. Evidence from magnetic anomalies and paleomagnetic data shows that between 67 and 49 million years ago spreading rates increased the Indian plate to anomalously rapid velocities, with a peak of nearly 200 mm/yr relative to the African plate. Cande and Stegman (2011) have shown new evidence that the Indian Plate acceleration was caused by a push force originating from the Reunion mantle plume. Two notable slowdowns occurred during that time period: a sharp reduction in velocity at 63 million years ago, and another more gradual reduction from 52 to 45 million years ago. The first slowdown coincides with rapidly dwindling flood basalt eruptions caused by the plume head of the Reunion mantle plume. The second slowdown is thought to be due to collision with either the Eurasian continent or a now extinct intermediate plate that may have contained an island arc. We are motivated to create a new visual model using new data and considering the Reunion plume as a driving force. Using the GPlates tectonics modeling software and rotation data developed by the EarthBytes Project we reconstruct the trajectory to develop a velocity vector model of the Indian plate. We use these tools to explore alternative plate reconstructions, such as one that includes a collision between India and a hypothetical intraoceanic arc beginning at 52 Ma (Ali and Aitchison, 2008) to help explain the reduction in plate velocity over the 7 million year span during the second slowdown.

  7. Predicting the influence of plate geometry on the eddy-current pendulum

    Science.gov (United States)

    Weigel, Catherine; Wachter, Jeremy M.; Wagoner, Paul; Atherton, Timothy J.

    2016-09-01

    We quantitatively analyze a familiar classroom demonstration, Van Waltenhofen's eddy current pendulum, to predict the damping effect for a variety of plate geometries from first principles. Results from conformal mapping, finite element simulations, and a simplified model suitable for introductory classes are compared with experiments.

  8. Predicting the Influence of Plate Geometry on the Eddy Current Pendulum

    CERN Document Server

    Weigel, Catherine; Wagoner, Paul; Atherton, Timothy J

    2015-01-01

    We quantitatively analyze a familiar classroom demonstration, Van Waltenhofen's eddy current pendulum, to predict the damping effect for a variety of plate geometries from first principles. Results from conformal mapping, finite element simulations and a simplified model suitable for introductory classes are compared with experiments.

  9. Higher order equivalent edge currents for fringe wave radar scattering by perfectly conducting polygonal plates

    DEFF Research Database (Denmark)

    Breinbjerg, Olav

    1992-01-01

    An approach for including higher order edge diffraction in the equivalent edge current (EEC) method is proposed. This approach, which applies to monostatic as well as bistatic radar configurations with perfectly conducting polygonal plates, involves three distinct sets of EECs. All of these sets ...

  10. Nonmonotonic effects of perpendicular magnetic anisotropy on current-driven vortex wall motions in magnetic nanostripes

    Science.gov (United States)

    Su, Yuan-Chang; Lei, Hai-Yang; Hu, Jing-Guo

    2015-09-01

    In a magnetic nanostripe, the effects of perpendicular magnetic anisotropy (PMA) on the current-driven horizontal motion of vortex wall along the stripe and the vertical motion of the vortex core are studied by micromagnetic simulations. The results show that the horizontal and vertical motion can generally be monotonously enhanced by PMA. However, when the current is small, a nonmonotonic phenomenon for the horizontal motion is found. Namely, the velocity of the horizontal motion firstly decreases and then increases with the increase of the PMA. We find that the reason for this is that the PMA can firstly increase and then decrease the confining force induced by the confining potential energy. In addition, the PMA always enhances the driving force induced by the current. Project supported by the National Natural Science Foundation of China (Grant Nos. 11247026 and 11374253).

  11. Effect of Joule heating in current-driven domain wall motion

    OpenAIRE

    Yamaguchi, A.; Tanigawa, H.; Ono, T.; Nasu, S; Miyake, K.; Mibu, K.; Shinjo, T.

    2004-01-01

    It was found that high current density needed for the current-driven domain wall motion results in the Joule heating of the sample. The sample temperature, when the current-driven domain wall motion occurred, was estimated by measuring the sample resistance during the application of a pulsed-current. The sample temperature was 750 K for the threshold current density of 6.7 x 10^11 A/m2 in a 10 nm-thick Ni81Fe19 wire with a width of 240 nm. The temperature was raised to 830 K for the current d...

  12. Greenland Fracture Zone-East Greenland Ridge(s) revisited: Indications of a C22-change in plate motion?

    DEFF Research Database (Denmark)

    Døssing, Arne; Funck, T.

    2012-01-01

    Fracture Zone and separation of the 200-km-long, fracture-zone-parallel continental East Greenland Ridge from the Eurasia plate is thought to be related to a major change in relative plate motions between Greenland and Eurasia during the earliest Oligocene (Chron 13 time). This study presents...... a reinterpretation of the Greenland Fracture Zone -East Greenland Ridge based on new and existing geophysical data. Evidence is shown for two overstepping ridge segments (Segments A and B) of which Segment A corresponds to the already known East Greenland Ridge while Segment B was not detected previously....... Interpretation of sonobuoy data and revised modeling of existing OBS data across Segment B indicate a continental composition of the segment. This interpretation is supported by magnetic anomaly data. The Segments A and B are bounded by portions of the Greenland Fracture Zone with a distinct similar to 10...

  13. PLATE

    DEFF Research Database (Denmark)

    Kling, Joyce; Hjulmand, Lise-Lotte

    2008-01-01

    ’s level of English is sufficient for the increasing number of courses offered in English each semester. This paper addresses these concerns and describes a pilot project initiated in 2003 at CBS to gauge the overall English language proficiency of those teaching content courses in English. Through......Copenhagen Business School (CBS) finds itself needing to address the issue of English-medium instruction for its increasing number of foreign exchange and full degree students. With internationalisation as a main pillar of the institution’s agenda, there are concerns whether the teaching faculty...... the Project in Language Assessment for Teaching in English (PLATE) language professionals from CBS’s Language Center observe teachers and provide feedback using evaluation criteria from the Common European Framework for Reference (CEFR) supplemented by some additional criteria which take the LSP nature...

  14. PLATE

    DEFF Research Database (Denmark)

    Kling, Joyce; Hjulmand, Lise-Lotte

    2008-01-01

    Copenhagen Business School (CBS) finds itself needing to address the issue of English-medium instruction for its increasing number of foreign exchange and full degree students. With internationalisation as a main pillar of the institution’s agenda, there are concerns whether the teaching faculty......’s level of English is sufficient for the increasing number of courses offered in English each semester. This paper addresses these concerns and describes a pilot project initiated in 2003 at CBS to gauge the overall English language proficiency of those teaching content courses in English. Through...... the Project in Language Assessment for Teaching in English (PLATE) language professionals from CBS’s Language Center observe teachers and provide feedback using evaluation criteria from the Common European Framework for Reference (CEFR) supplemented by some additional criteria which take the LSP nature...

  15. The current sheet tiled and non-adiabatic ions effect on the flapping motion in magnetotail

    Science.gov (United States)

    Wei, XinHua

    2016-04-01

    The current sheet is a crucial region of the magnetotail, where energy reserve and release take place. The origin of the up-down motions of the current sheet, referred to as flapping motions, is among the most fundamental issues of magnetotail dynamics. Observational evidences suggest that the flapping motion is a kind of internal excited kink-like waves, but its particular propagating features such as the low phase speeds and the propagating direction from the tail center toward flanks do not match any local generation mechanisms previously established so far. Here we report observations of the current sheet flapping motions induced by non-adiabatic ions in the magnetic field configurations with a finite guiding component, whose population present periodic hemispherical asymmetries. These flapping motion current sheet cases often observed tiled. The current sheet flapping phenomenon implies that the excitation mechanism of the current sheet flapping motions is a self-circulation process between the non-adiabatic ion population and the current sheet equilibrium itself.

  16. Effect of Joule heating in current-driven domain wall motion

    OpenAIRE

    A., Yamaguchi; S., Nasu; H., Tanigawa; T., Ono; K., Miyake; Ko, Mibu; T., Shinjo

    2004-01-01

    It was found that high current density needed for the current-driven domain wall motion results in the Joule heating of the sample. The sample temperature, when the current-driven domain wall motion occurred, was estimated by measuring the sample resistance during the application of a pulsed current. The sample temperature was 750 K for the threshold current density of 6.7×1011 A/m2 in a 10-nm-thick Ni81Fe19 wire with a width of 240 nm on thermally oxidized silicon substrate. The temperature ...

  17. Current sheet flapping motions in the tailward flow of magnetic reconnection

    Science.gov (United States)

    Wu, Mingyu; Lu, Quanming; Volwerk, Martin; Vörös, Zoltán.; Ma, Xuanye; Wang, Shui

    2016-08-01

    The feature and origin of current sheet flapping motions are one of most interesting issues of magnetospheric dynamics. In this paper we report the flapping motion of the current sheet detected in the tailward flow of a magnetic reconnection event on 7 February 2009. This flapping motion with frequency about 12 mHz was accompanied by magnetic turbulence. The observations by the tail-elongated fleet of five Time History of Events and Macroscale Interactions during Substorms probes indicate that these flapping oscillations were rather confined within the tailward flow than were due to a global process. This flapping motion could be due to the instability driven by the free energy associated with the ion temperature anisotropy in the tailward flow. Our observations indicate that the flapping motion in the tailward flow could have a different generation mechanism with that in the earthward flow.

  18. Model of vertical plasma motion during the current quench

    Science.gov (United States)

    Kiramov, D. I.; Breizman, B. N.

    2017-10-01

    Tokamak disruptions impair plasma position control, which allows the plasma column to move and hit the wall. These detrimental events enhance thermal and mechanical loads due to halo currents and runaway electron losses. Their fundamental understanding and prevention is one of the high-priority items for ITER.

  19. Combined Plate Motion and Density Driven Flow in the Asthenosphere beneath Saudi Arabia: Evidence from Shearwave Splitting and Seismic Anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, S; Schwartz, S; Al-Amri, A; Rodgers, A

    2006-09-08

    Mantle anisotropy along the Red Sea and across the Arabian Peninsula was analyzed using shear-wave splitting recorded by stations from three different seismic networks: the largest, most widely distributed array of stations examined across the Arabian Peninsula to date. Stations near the Gulf of Aqaba display fast orientations aligned parallel to the Dead Sea Transform Fault, most likely related to the strike-slip motion between Africa and Arabia However, most of our observations across Arabia are statistically the same (at a 95% confidence level), with north-south oriented fast directions and delay times averaging about 1.4 s. Since end-member models of fossilized anisotropy and present-day asthenospheric flow do not adequately explain these observations, we interpret them as a combination of plate and density driven flow in the asthenosphere. Combining northeast oriented flow associated with absolute plate motion with northwest oriented flow associated with the channelized Afar upwelling along the Red Sea produces a north-south resultant that matches the observations and supports models of active rifting.

  20. Current-driven magnetic domain wall motion and its real-time detection

    Science.gov (United States)

    Kim, Kab-Jin; Yoshimura, Yoko; Ono, Teruo

    2017-08-01

    Current-controlled magnetic domain wall motion has opened the possibility of a novel type of shift register memory device, which has been optimistically predicted to replace existing magnetic memories. Owing to this promising prospect, intensive work has been carried out during the last few decades. In this article, we first review the progress in the study of current-induced magnetic domain wall motion. Underlying mechanisms behind the domain wall motion, which have been discovered during last few decades, as well as technological achievements are presented. We then present our recent experimental results on the real-time detection of current-driven multiple magnetic domain wall motion, which directly demonstrates the operation of a magnetic domain wall shift register.

  1. What drives microplate motion and deformation in the northeastern Caribbean plate boundary region?

    NARCIS (Netherlands)

    van Benthem, S.A.C.|info:eu-repo/dai/nl/304833657; Govers, R.|info:eu-repo/dai/nl/108173836; Wortel, R.|info:eu-repo/dai/nl/068439202

    2014-01-01

    The north Caribbean plate boundary zone is a broad deformation zone with several fault systems and tectonic blocks that move with different velocities. The indentation by the Bahamas Platform (the “Bahamas Collision”) is generally invoked as a cause of this fragmentation. We propose that a second

  2. What drives microplate motion and deformation in the northeastern Caribbean plate boundary region?

    NARCIS (Netherlands)

    van Benthem, S.A.C.|info:eu-repo/dai/nl/304833657; Govers, R.|info:eu-repo/dai/nl/108173836; Wortel, R.|info:eu-repo/dai/nl/068439202

    2014-01-01

    The north Caribbean plate boundary zone is a broad deformation zone with several fault systems and tectonic blocks that move with different velocities. The indentation by the Bahamas Platform (the “Bahamas Collision”) is generally invoked as a cause of this fragmentation. We propose that a second dr

  3. Statistical research on the motion properties of the magnetotail current sheet:Cluster observations

    Institute of Scientific and Technical Information of China (English)

    H.REME; E.LUCEK

    2010-01-01

    The origin of the flapping motion of the earth’s magnetotail current sheet is one of the most important problems in the magnetotail dynamics.Using Cluster data,we make a statistical research on the motion properties of the magnetotail current sheet of 2001 and 2003.We calculate the velocities of the magnetotail current sheet using new methods and obtain the distribution of the magnetotail current sheet velocities in the X-Y plane in GSE coordinate system.Our results show that although most of the current sheets were propagating toward the tail flanks and those of the exceptions lay in dusk side,which is consistent with previous studies,the proportions of the current sheet which were propagating toward midnight (where |YGSE|=0) were higher than those in previous studies.Motions of the current sheet in the middle area (|YGSE|<8 Re) of the magnetotail are investigated.Relatively high value of the Z component of the velocity further confirms that the middle area of the magnetotail might be a source region for the motion of the current sheets which were propagating towards the tail flanks.According to our case studies,the way the current sheets propagated toward midnight area differs significantly from that toward dusk and dawn side,from which we infer that there might be two different kinds of current sheet motions originated from different sources.The statistical results of this paper may give some clues for further studies on the origin of the flapping motion of the magnetotail current sheet.

  4. Flapping current sheet motions in magnetotail excited by non-adiabatic ions: case study

    Science.gov (United States)

    Wei, X., Jr.

    2015-12-01

    The current sheet is a crucial region of the magnetotail, where energy reserve and release take place. The origin of the up-down motions of the current sheet, referred to as flapping motions, is among the most fundamental issues of magnetotail dynamics. Observational evidences suggest that the flapping motion is a kind of internal excited kink-like waves, but its particular propagating features such as the low phase speeds and the propagating direction from the tail center toward flanks do not match any local generation mechanisms previously established so far. Here we report observations of the current sheet flapping motions induced by non-adiabatic ions in the magnetic field configurations with a finite guiding component, whose population present periodic hemispherical asymmetries. Three type of current sheet flapping event in this paper will be discussed. This current sheet flapping phenomenon implies that the excitation mechanism of the current sheet flapping motions is a self-circulation process between the non-adiabatic ion population and the current sheet equilibrium itself.

  5. MAGNETIC-ELASTIC BUCKLING OF A THIN CURRENT CARRYING PLATE SIMPLY SUPPORTED AT THREE EDGES

    Institute of Scientific and Technical Information of China (English)

    WANG Zhiren; WANG Ping; BAI Xiangzhong

    2008-01-01

    The magnetic-elasticity buckling problem of a current plate under the action of a mechanical load in a magnetic field was studied by using the Mathieu function. According to the magnetic-elasticity non-linear kinetic equation, physical equations, geometric equations, the expression for Lorenz force and the electrical dynamic equation, the magnetic-elasticity dynamic buckling equation is derived. The equation is changed into a standard form of the Mathieu equation using Galerkin's method. Thus, the buckling problem can be solved with a Mathieu equation. The criterion equation of the buckling problem also has been obtained by discussing the eigenvalue relation of the coefficients λ and η in the Mathieu equation. As an example, a thin plate simply supported at three edges is solved here. Its magnetic-elasticity dynamic buckling equation and the relation curves of the instability state with variations in some parameters are also shown in this paper. The conclusions show that the electrical magnetic forces may be controlled by changing the parameters of the current or the magnetic field so that the aim of controlling the deformation, stress, strain and stability of the current carrying plate is achieved.

  6. Motion

    CERN Document Server

    Graybill, George

    2007-01-01

    Take the mystery out of motion. Our resource gives you everything you need to teach young scientists about motion. Students will learn about linear, accelerating, rotating and oscillating motion, and how these relate to everyday life - and even the solar system. Measuring and graphing motion is easy, and the concepts of speed, velocity and acceleration are clearly explained. Reading passages, comprehension questions, color mini posters and lots of hands-on activities all help teach and reinforce key concepts. Vocabulary and language are simplified in our resource to make them accessible to str

  7. Numerical analysis of angular defects in bent plates using tone burst eddy-current thermography (TBET)

    Science.gov (United States)

    Libin, M. N.; Balasubramaniam, Krishnan; Maxfield, B. W.

    2013-01-01

    Tone Burst Eddy current Thermography (TBET) is a new hybrid, non-contacting, Non-Destructive Evaluation (NDT) method which employs a combination of Pulsed Eddy current Thermography (PEC) and Thermographic Non-Destructive Evaluation (TNDE). For understanding angular cracks, fundamental knowledge about the induced current density distribution in the component under test is required. Further, this information enables us to find the amount of heat produced at those locations and how it diffuses to the surface. This paper describes simulation work done for cracks set at an angle to the surface in flat and bent aluminum plates. The investigation is implemented by the simulating transient thermal distribution for 2D angular cracks via finite element package COMSOL multi-physics with AC/DC module and general heat transfer. At crack edges, induced current is seen concentrated thus indicating a localized high heating in those areas relative to other regions. A numerical study was also carried out by varying parameters like crack angle (0°, 22.5°, 45°, 67.5°) and crack length (0.6mm, 1.2mm, 1.8mm) the transient thermal distributions were compared for different plate bend angles (180°, 120°, 90°, 60°, 30°). TBET method was found well suited for the detection of service induced cracks, usually caused by either rolling contact fatigue or stress corrosion, with a high degree of sensitivity.

  8. Screw augmentation reduces motion at the bone-implant interface: a biomechanical study of locking plate fixation of proximal humeral fractures.

    Science.gov (United States)

    Schliemann, Benedikt; Seifert, Robert; Rosslenbroich, Steffen B; Theisen, Christina; Wähnert, Dirk; Raschke, Michael J; Weimann, Andre

    2015-12-01

    Shear forces at the bone-implant interface lead to a loss of reduction after locking plate fixation of proximal humeral fractures. The aim of the study was to analyze the roles of medial support screws and screw augmentation in failure loads and motion at the bone-implant interface after locking plate fixation of proximal humeral fractures. Unstable 3-part fractures were simulated in 6 pairs of cadaveric humeri and were fixed with a DiPhos-H locking plate (Lima Corporate, Udine, Italy). An additional medial support screw was implanted in 1 humerus of every donor. The opposite humerus was stabilized with a medial support screw and additional bone cement augmentation of the 2 anteriorly directed head screws. Specimens were loaded in the varus bending position. Stiffness, failure loads, plate bending, and the motion at the bone-implant interface were evaluated using an optical motion capture system. The mean load to failure was 669 N (standard deviation [SD], 117 N) after fixation with medial support screws alone and 706 N (SD, 153 N) after additional head screw augmentation (P = .646). The initial stiffness was 453 N/mm (SD, 4.16 N/mm) and 461 N/mm (SD, 64.3 N/mm), respectively (P = .594). Plate bending did not differ between the 2 groups. However, motion at the bone-implant interface was significantly reduced after head screw augmentation (P Board of Trustees. Published by Elsevier Inc. All rights reserved.

  9. Motion-induced eddy current thermography for high-speed inspection

    Science.gov (United States)

    Wu, Jianbo; Li, Kongjing; Tian, Guiyun; Zhu, Junzhen; Gao, Yunlai; Tang, Chaoqing; Chen, Xiaotian

    2017-08-01

    This letter proposes a novel motion-induced eddy current based thermography (MIECT) for high-speed inspection. In contrast to conventional eddy current thermography (ECT) based on a time-varying magnetic field created by an AC coil, the motion-induced eddy current is induced by the relative motion between magnetic field and inspected objects. A rotating magnetic field created by three-phase windings is used to investigate the heating principle and feasibility of the proposed method. Firstly, based on Faraday's law the distribution of MIEC is investigated, which is then validated by numerical simulation. Further, experimental studies are conducted to validate the proposed method by creating rotating magnetic fields at different speeds from 600 rpm to 6000 rpm, and it is verified that rotating speed will increase MIEC intensity and thereafter improve the heating efficiency. The conclusion can be preliminarily drawn that the proposed MIECT is a platform suitable for high-speed inspection.

  10. Structure design and motion simulation of the pin-cycloid gear planetary reducer with ring-plate-type

    Science.gov (United States)

    Duan, Hongjie; Li, Lijun; Tao, Junyi

    2017-06-01

    The pin-cycloid gear planetary reducer with ring-plate-type is a new type of reducers. It has high transmission ratio range and high efficiency. In this paper the working principle of pin-cycloid gear planetary reducer is discussed, and the structure of the reducer is designed. Especially for the complexity and the difficulty in modelling of the cycloid gear tooth profile, the parametric design module of cycloid gear is developed to solve the cycloid gear modelling problem through the second development of Solid Works. At last, the speed schemes of the input shaft and output shaft of the reducer are obtained by the motion simulation. Through the analysis of the simulation curves, the rationality of the structure design is proved, which provides a theoretical basis for the design and manufacture of the reducer.

  11. Transient Eddy Current Response Due to a Subsurface Crack in a Conductive Plate

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Fangwei [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    Eddy current nondestructive evaluation (NDE) is usually carried out by exciting a time harmonic field using an inductive probe. However, a viable alternative is to use transient eddy current NDE in which a current pulse in a driver coil produces a transient .eld in a conductor that decays at a rate dependent on the conductivity and the permeability of the material and the coil configuration. By using transient eddy current, it is possible to estimate the properties of the conductive medium and to locate and size potential .aws from the measured probe response. The fundamental study described in this dissertation seeks to establish a theoretical understanding of the transient eddy current NDE. Compared with the Fourier transform method, the derived analytical formulations are more convenient when the transient eddy current response within a narrow time range is evaluated. The theoretical analysis provides a valuable tool to study the effect of layer thickness, location of defect, crack opening as well as the optimization of probe design. Analytical expressions have been developed to evaluate the transient response due to eddy currents in a conductive plate based on two asymptotic series. One series converges rapidly for a short time regime and the other for a long time regime and both of them agree with the results calculated by fast Fourier transform over all the times considered. The idea of asymptotic expansion is further applied to determine the induced electromotive force (EMF) in a pick-up coil due to eddy currents in a cylindrical rod. Starting from frequency domain representation, a quasi-static time domain dyadic Green's function for an electric source in a conductive plate has been derived. The resulting expression has three parts; a free space term, multiple image terms and partial reflection terms. The dyadic Green's function serves as the kernel of an electric field integral equation which defines the interaction of an ideal crack with the

  12. Abrupt Change in North American Plate Motion: Magnetostratigraphy and Paleopoles of the Early Jurassic Moenave Formation

    Science.gov (United States)

    Hutny, M. K.; Steiner, M. B.

    2001-12-01

    The J-1 cusp marks a dramatic ~ 180° change in the apparent motion of the magnetic pole with respect to North America. The cusp is defined by a sequence of poles: Chinle - Moenave - Kayenta. The Moenave pole (Ekstrand and Butler, 1989), which forms the point of the cusp, was obtained primarily from the lower member (Dinosaur Canyon) of the three-member Moenave Formation. We present new paleomagnetic data from the upper two members (Whitmore Point and Springdale Sandstone) of the formation. The Vermillion Cliffs in southern Utah present excellent exposures of the Moenave Formation. At this location, the Moenave rests uncomformably on the Late Triassic Chinle Group, although to the southeast it overlies it in a conformable manner. The Moenave is seemingly conformably overlain by the Kayenta Formation. Our study identified six polarity intervals in 100 meters of section. A preliminary paleopole from the Whitmore Point Member falls within the 95% confidence limits of the Dinosaur Canyon pole (Ekstrand and Butler, 1989), as does our pole from the top Springdale Sandstone member. If the apparent polar wander does indeed represent motion of the North American continent, then the reversal in direction implied by the J-1 cusp takes place after the deposition of the Springdale Sandstone, and either before or during the deposition of the lower Kayenta Formation. No directions intermediate between the Moenave and Kayenta directions were observed up through the uppermost Moenave strata. Within the Moenave, the lack of discernable change in magnetic direction between the three members suggests continuous deposition. This result is consistent with the observed mutually interfingering nature of the Whitmore Point and Springdale Sandstone. The sudden change in magnetic direction between the top of the Moenave and the Kayenta suggests the possibility of an unconformity between the two formations, and/or rapid continental motion following the turnaround.

  13. Effect of sodium dodecylbenzene sulfonate on the motion of three-phase contact lines on the Wilhelmy plate surface.

    Science.gov (United States)

    Karakashev, Stoyan I; Phan, Chi M; Nguyen, Anh V

    2005-11-15

    The combined approach of the molecular-kinetic and hydrodynamic theories for description of the motion of three-phase gas-liquid-solid contact lines has been examined using the Wilhelmy plate method. The whole dynamic meniscus has been divided into molecular, hydrodynamic, and static-like regions. The Young-Laplace equation and the molecular-kinetic and hydrodynamic dewetting theories have been applied to describe the meniscus profiles and contact angle. The dissipative forces accompanying the dynamic dewetting have also been investigated. The experiments with a Wilhelmy plate made from an acrylic polymer sheet were carried out using a computerized apparatus for contact angle analysis (OCA 20, DataPhysics, Germany). The extrapolated dynamic contact angle versus velocity of the three-phase contact line for Milli-Q water and 5x10(-4) M SDBS solution was experimentally obtained and compared with the combined MHD models with low and moderate Reynolds numbers. The models predict similar results for the extrapolated contact angle. SDBS decreases the equilibrium contact angle and increases the molecular jumping length but does not affect the molecular frequency significantly. The hydrodynamic deformation of the meniscus, viscous dissipation, and friction were also influenced by the SDBS surfactant.

  14. Effects of parabolic motion on an isothermal vertical plate with constant mass flux

    Directory of Open Access Journals (Sweden)

    R. Muthucumaraswamy

    2014-12-01

    Full Text Available An analytical study of free convection flow near a parabolic started infinite vertical plate with isothermal in the presence of uniform mass flux was considered. The mathematical model is reduced to a system of linear partial differential equations for the velocity, the concentration and the temperature; the closed form exact solutions were obtained by the Laplace transform technique. The velocity, temperature and concentration profiles for the different parameters as thermal Grashof number Gr, mass Grashof number Gc, Prandtl number Pr, Schmidt number Sc and time t were graphed and the numerical values for the skin friction were as tabulated. It is observed that the velocity is enhanced as the time increased and the velocity is decreased as the Prandtl number increased.

  15. A review of the current state of digital plate reading of cultures in clinical microbiology.

    Science.gov (United States)

    Rhoads, Daniel D; Novak, Susan M; Pantanowitz, Liron

    2015-01-01

    Digital plate reading (DPR) is increasingly being adopted as a means to facilitate the analysis and improve the quality and efficiency within the clinical microbiology laboratory. This review discusses the role of DPR in the context of total laboratory automation and explores some of the platforms currently available or in development for digital image capturing of microbial growth on media. The review focuses on the advantages and challenges of DPR. Peer-reviewed studies describing the utility and quality of these novel DPR systems are largely lacking, and professional guidelines for DPR implementation and quality management are needed. Further development and more widespread adoption of DPR is anticipated.

  16. Effects of Radiation and free Convection Currents on Unsteady Couette Flow between two Vertical Parallel Plates with Constant Heat flux and Heat Source Through Porous Medium

    Directory of Open Access Journals (Sweden)

    Damala Ch Kesavaiah

    2013-04-01

    Full Text Available The present study the free convection in unsteady Couette flow of a viscous incompressible fluid confined between two vertical parallel plates in the presence of thermal radiation with heat source in the presence of uniform magnetic field is presented. The flow is induced by means of Couette motion and free convection currents occurring as a result of application of constant heat flux on the wall with a uniform vertical motion in its own plane while constant temperature on the stationary wall. The fluid considered here is a gray, absorbing-emitting but non-scattering medium, and the Rosseland approximation is used to describe the radiative heat flux in the analysis. The dimensionless governing partial differential equations are solved by using regular perturbation technique. The results for the velocity, temperature and the skin-friction are shown graphically. The effects of different parameters are discussed.

  17. The Rift Valley of African Plate in Elasto-Plastic Creeping over Magma Motion

    Science.gov (United States)

    Nakamura, Shigehisa

    2016-04-01

    This is a brief note to a problem on the Rift Valley in the eastern Africa. It is said that this valley was formed in an age 20,000,000 years before present though the valley is yet continuing to move eastward at an annual rate of about 5 cm/year in a geographical trend. Adding to some of the scientists tell that the separation threat of the easternAfrica from the mother land of the Africa under the effect of African crust motion over the magma. However, it is now geological understanding that the land of the Africa has been kept its basic coastal configulation in geographic pattern since the time more than 20,000,000 years before present. Sothat, it is hard to consider the above noted African land separation by part could be in the next age in a time scale of 20,000,000 years. As far as, we concern the geographic data obtaoned by the ground based survey of the African typical mountain peaks, the highest mountain peak 5885m (in 1980) is for Kilimanjaro, Kibo Peak though one of the scientific almanacs tells us its peak height as 5890m (in 2009). As for the Mount Kenia, the peak height is as 5199m (in 1980) and 5200m(in 2009). At a glance, it looks to be a trend in altimetry of the African typical mountain. Now, what trends are noted for the peak heights could be taken to suggesting the geological activity on the earth surface to maintain in a spherical shape approximately on the orbit around the Sun. In these several ten years, the digitizing of the data has been promoted even for the topographic patterns on the earth though its time scaling is extremely short comparing to the geological time scaling. Now, it should be found what is effective to monitor any trends of the African crust in motion as well as variations of the mountain peaks.

  18. Effect of contact line dynamics on the thermocapillary motion of a droplet on an inclined plate.

    Science.gov (United States)

    Karapetsas, George; Sahu, Kirti Chandra; Matar, Omar K

    2013-07-16

    We study the two-dimensional dynamics of a droplet on an inclined, nonisothermal solid substrate. We use lubrication theory to obtain a single evolution equation for the interface, which accounts for gravity, capillarity, and thermo-capillarity, brought about by the dependence of the surface tension on temperature. The contact line motion is modeled using a relation that couples the contact line speed to the difference between the dynamic and equilibrium contact angles. The latter are allowed to vary dynamically during the droplet motion through the dependence of the liquid-gas, liquid-solid, and solid-gas surface tensions on the local contact line temperature, thereby altering the local substrate wettability at the two edges of the drop. This is an important feature of our model, which distinguishes it from previous work wherein the contact angle was kept constant. We use finite-elements for the discretization of all spatial derivatives and the implicit Euler method to advance the solution in time. A full parametric study is carried out in order to investigate the interplay between Marangoni stresses, induced by thermo-capillarity, gravity, and contact line dynamics in the presence of local wettability variations. Our results, which are generated for constant substrate temperature gradients, demonstrate that temperature-induced variations of the equilibrium contact angle give rise to complex dynamics. This includes enhanced spreading rates, nonmonotonic dependence of the contact line speed on the applied substrate temperature gradient, as well as "stick-slip" behavior. The mechanisms underlying this dynamics are elucidated herein.

  19. The effect of plate motion history on the longevity of deep mantle heterogeneities

    Science.gov (United States)

    Bull, Abigail L.; Domeier, Mathew; Torsvik, Trond H.

    2014-09-01

    Understanding the first-order dynamical structure and evolution of Earth's mantle is a fundamental goal in solid-earth geophysics. Tomographic observations reveal a lower mantle characterised by higher-than-average shear-wave speeds beneath Asia and encircling the Pacific, consistent with cold slabs beneath regions of ancient subduction, and lower-than-average shear-wave speeds in broad regional areas beneath Africa and the Central Pacific (termed LLSVPs). The LLSVPs are not well understood from a dynamical perspective and their origin and evolution remain enigmatic. Some numerical studies propose that the LLSVP beneath Africa is post-Pangean in origin, formed as a result of return flow in the mantle due to circum-Pangean subduction, countered by an older Pacific LLSVP, suggested to have formed during the break up of Rodinia. This propounds that, prior to the formation of Pangea, the lower mantle was dominated by a degree-1 convection pattern with a major upwelling centred close to the present-day Pacific LLSVP and subduction concentrated mainly in the antipodal hemisphere. In contrast, palaeomagnetic observations which proffer a link between the reconstructed eruption sites of Phanerozoic kimberlites and Large Igneous Provinces with regions on the margins of the present-day LLSVPs suggest that the anomalies may have remained stationary for at least the last 540 Myr and further that the anomalies were largely insensitive to the formation and subsequent break-up of Pangea. Here we investigate the evolution and long-term stability of LLSVP-like structures in Earth's mantle by integrating plate tectonics and numerical models of global thermochemical mantle dynamics. We explore the possibility that either one or both LLSVPs existed prior to the formation of Pangea and improve upon previous studies by using a new, true polar wander-corrected global plate model to impose surface velocity boundary conditions for a time interval that spans the amalgamation and subsequent

  20. Heat transfer between two parallel porous plates for Couette flow under pressure gradient and Hall current

    Indian Academy of Sciences (India)

    Hazem A Attia; W Abbas; Mostafa A M Abdeen; Ahmed A M Said

    2015-02-01

    The aim of the present paper is to study the unsteady magneto-hydrodynamic viscous Couette flow with heat transfer in a Darcy porous medium between two infinite parallel porous plates considering Hall effect, and temperature dependent physical properties under constant pressure gradient. The parallel plates are assumed to be porous and subjected to a uniform suction from above and injection from below while the fluid is flowing through a porous medium that is assumed to obey Darcy’s law. A numerical solution for the governing nonlinear partial differential equations coupled with set of momentum equations and the energy equation including the viscous and Joule dissipations is adopted. The effect of the porosity of the medium, the Hall current and the temperature dependent viscosity and thermal conductivity on both the velocity and temperature distributions are investigated. It is found that the porosity numberMhas a marked effect on decreasing the velocity distribution (owing to a simultaneous increase in Darcy porous drag). Also the temperature T is decreased considerably with increasing porosity number.With increasing Hall current parameter m, the velocity component u (x-direction) is considerably increased, whereas velocity component w (z-direction) is reduced. Temperatures are decreased in the early stages of flow but effectively increased in the steady state with increasing m.

  1. Rotating ferro-nanofluid over stretching plate under the effect of hall current and joule heating

    Science.gov (United States)

    Abdel-Wahed, Mohamed S.

    2017-05-01

    The behavior of boundary layer over a stretching plate filled with ferromagnetic Fe3O4 nanoparticles and subjected to magnetic field with hall current, joule heating and nonlinear thermal radiation has been investigated. The modeling based on nonlinear partial differential equations due to continuity, momentum and heat equations, these equations transformed to a system of nonlinear ordinary differential equations using similarity transformation technique then solved numerically. The effect of hall current, joule heating and thermal radiation on the physical quantities such as surface shear stress and heat flux have been investigated and discussed. Moreover, the velocities and temperature profiles of the boundary layer under the influence of the presented external forces plotted and discussed.

  2. High-resolution estimates of Nubia-Somalia plate motion since 20 Ma from reconstructions of the Southwest Indian Ridge, Red Sea, and Gulf of Aden

    Science.gov (United States)

    DeMets, C.; Merkouriev, S.

    2016-07-01

    Large gaps and inconsistencies remain in published estimates of Nubia-Somalia plate motion based on reconstructions of seafloor spreading data around Africa. Herein, we use newly available reconstructions of the Southwest Indian Ridge at ˜1-Myr intervals since 20 Ma to estimate Nubia-Somalia plate motion farther back in time than previously achieved and with an unprecedented degree of temporal resolution. At the northern end of the East African rift, our new estimates of Nubia-Somalia motion for six times from 0.78 Ma to 5.2 Ma differ by only 2% from the rift-normal component of motion that is extrapolated from a recently estimated GPS angular velocity. The rate of rift-normal extension thus appears to have remained steady since at least 5.2 Ma. Our new rotations indicate that the two plates have moved relative to each other since at least 16 Ma and possibly longer. Motion has either been steady since at least 16 Ma or accelerated modestly between 6 and 5.2 Ma. Our Nubia-Somalia rotations predict 42.5±3.8 km of rift-normal extension since 10.6 Ma across the well-studied, northern segment of the Main Ethiopian Rift, consistent with 40-50 km estimates for extension since 10.6 Myr based on seismological surveys of this narrow part of the plate boundary. Nubia-Somalia rotations are also derived by combining newly estimated Somalia-Arabia rotations that reconstruct the post-20-Ma opening of the Gulf of Aden with Nubia-Arabia rotations estimated via a probabilistic analysis of plausible opening scenarios for the Red Sea. These rotations predict Nubia-Somalia motion since 5.2 Myr that is consistent with that determined from Southwest Indian Ridge data and also predict 40±3 km of rift-normal extension since 10.6 Ma across the Main Ethiopian Rift, consistent with our 42.5±3.8 km Southwest Indian Ridge estimate. Our new rotations exclude at high confidence level previous estimates of 12±13 km and 123±14 km for rift-normal extensions across the Main Ethiopian Rift since

  3. High-resolution estimates of Nubia-Somalia plate motion since 20 Ma from reconstructions of the Southwest Indian Ridge, Red Sea and Gulf of Aden

    Science.gov (United States)

    DeMets, C.; Merkouriev, S.

    2016-10-01

    Large gaps and inconsistencies remain in published estimates of Nubia-Somalia plate motion based on reconstructions of seafloor spreading data around Africa. Herein, we use newly available reconstructions of the Southwest Indian Ridge at ˜1-Myr intervals since 20 Ma to estimate Nubia-Somalia plate motion farther back in time than previously achieved and with an unprecedented degree of temporal resolution. At the northern end of the East African rift, our new estimates of Nubia-Somalia motion for six times from 0.78 Ma to 5.2 Ma differ by only 2 per cent from the rift-normal component of motion that is extrapolated from a recently estimated GPS angular velocity. The rate of rift-normal extension thus appears to have remained steady since at least 5.2 Ma. Our new rotations indicate that the two plates have moved relative to each other since at least 16 Ma and possibly longer. Motion has either been steady since at least 16 Ma or accelerated modestly between 6 and 5.2 Ma. Our Nubia-Somalia rotations predict 42.5 ± 3.8 km of rift-normal extension since 10.6 Ma across the well-studied, northern segment of the Main Ethiopian Rift, consistent with 40-50 km estimates for extension since 10.6 Myr based on seismological surveys of this narrow part of the plate boundary. Nubia-Somalia rotations are also derived by combining newly estimated Somalia-Arabia rotations that reconstruct the post-20-Ma opening of the Gulf of Aden with Nubia-Arabia rotations estimated via a probabilistic analysis of plausible opening scenarios for the Red Sea. These rotations predict Nubia-Somalia motion since 5.2 Myr that is consistent with that determined from Southwest Indian Ridge data and also predict 40 ± 3 km of rift-normal extension since 10.6 Ma across the Main Ethiopian Rift, consistent with our 42.5 ± 3.8 km Southwest Indian Ridge estimate. Our new rotations exclude at high confidence level previous estimates of 12 ± 13 and 123 ± 14 km for rift-normal extensions across the Main

  4. Intermediate crust (IC); its construction at continent edges, distinctive epeirogenic behaviour and identification as sedimentary basins within continents: new light on pre-oceanic plate motions

    Science.gov (United States)

    Osmaston, Miles F.

    2014-05-01

    Introduction. The plate tectonics paradigm currently posits that the Earth has only two kinds of crust - continental and oceanic - and that the former may be stretched to form sedimentary basins or the latter may be modified by arc or collision until it looks continental. But global analysis of the dynamics of actual plate motions for the past 150 Ma indicates [1 - 3] that continental tectospheres must be immensely thicker and rheologically stiffer than previously thought; almost certainly too thick to be stretched with the forces available. In the extreme case of cratons, these tectospheric keels evidently extend to 600 km or more [2, 3]. This thick-plate behaviour is attributable, not to cooling but to a petrological 'stiffening' effect, associated with a loss of water-weakening of the mineral crystals, which also applies to the hitherto supposedly mobile LVZ below MORs [4, 5]. The corresponding thick-plate version of the mid-ocean ridge (MOR) process [6 - 8], replacing the divergent mantle flow model, has a deep, narrow wall-accreting axial crack which not only provides the seismic anisotropy beneath the flanks but also brings two outstanding additional benefits:- (i) why, at medium to fast spreading rates, MOR axes become straight and orthogonally segmented [6], (ii) not being driven by body forces, it can achieve the sudden jumps of axis, spreading-rate and direction widely present in the ocean-floor record. Furthermore, as we will illustrate, the crack walls push themselves apart at depth by a thermodynamic mechanism, so the plates are not being pulled apart. So the presence of this process at a continental edge would not imply the application of extensional force to the margin. Intermediate Crust (IC). In seeking to resolve the paradox that superficially extensional structures are often seen at margins we will first consider how this MOR process would be affected by the heavy concurrent sedimentation to be expected when splitting a mature continent. I reason

  5. Mutual Inductance Problem for a System Consisting of a Current Sheet and a Thin Metal Plate

    Science.gov (United States)

    Fulton, J. P.; Wincheski, B.; Nath, S.; Namkung, M.

    1993-01-01

    Rapid inspection of aircraft structures for flaws is of vital importance to the commercial and defense aircraft industry. In particular, inspecting thin aluminum structures for flaws is the focus of a large scale R&D effort in the nondestructive evaluation (NDE) community. Traditional eddy current methods used today are effective, but require long inspection times. New electromagnetic techniques which monitor the normal component of the magnetic field above a sample due to a sheet of current as the excitation, seem to be promising. This paper is an attempt to understand and analyze the magnetic field distribution due to a current sheet above an aluminum test sample. A simple theoretical model, coupled with a two dimensional finite element model (FEM) and experimental data will be presented in the next few sections. A current sheet above a conducting sample generates eddy currents in the material, while a sensor above the current sheet or in between the two plates monitors the normal component of the magnetic field. A rivet or a surface flaw near a rivet in an aircraft aluminum skin will disturb the magnetic field, which is imaged by the sensor. Initial results showed a strong dependence of the flaw induced normal magnetic field strength on the thickness and conductivity of the current-sheet that could not be accounted for by skin depth attenuation alone. It was believed that the eddy current imaging method explained the dependence of the thickness and conductivity of the flaw induced normal magnetic field. Further investigation, suggested the complexity associated with the mutual inductance of the system needed to be studied. The next section gives an analytical model to better understand the phenomenon.

  6. A quantitative description of end-plate currents in the presence of two lidocaine derivatives.

    Science.gov (United States)

    Beam, K G

    1976-06-01

    1. Possible ways in which local anaesthetics may act to produce their characteristic alterations of end-plate current (e.p.c.s) are considered. 2. Following Magleby & Stevens (1972b), it is proposed that when acetylcholine (ACh) binds to its end-plate receptor it induces a conformational change which causes an increased ionic permeability and, thus, the measured e.p.c.; the reverse conformational change which returns the permeability to its resting state is postulated to be the rate-limiting event for e.p.c. decay whether or not local anaesthetics are present. Moreover, it is proposed that the ACh receptor had multiple binding sites and the local anaesthetics can bind to one or more of these sites thereby altering the conformational changes induced when ACh binds to remaining sites. 3. Equations based on this proposal are developed and are shown to provide an accurate description of the entire e.p.c. time couse as modified by eith QX-222 or QX-314. 4. Other models are also discussed; models in which local anaesthetic molecules bind only after receptor activation appear to be ruled out.

  7. WormAssay: a novel computer application for whole-plate motion-based screening of macroscopic parasites.

    Directory of Open Access Journals (Sweden)

    Chris Marcellino

    2012-01-01

    Full Text Available Lymphatic filariasis is caused by filarial nematode parasites, including Brugia malayi. Adult worms live in the lymphatic system and cause a strong immune reaction that leads to the obstruction of lymph vessels and swelling of the extremities. Chronic disease leads to the painful and disfiguring condition known as elephantiasis. Current drug therapy is effective against the microfilariae (larval stage of the parasite, but no drugs are effective against the adult worms. One of the major stumbling blocks toward developing effective macrofilaricides to kill the adult worms is the lack of a high throughput screening method for candidate drugs. Current methods utilize systems that measure one well at a time and are time consuming and often expensive. We have developed a low-cost and simple visual imaging system to automate and quantify screening entire plates based on parasite movement. This system can be applied to the study of many macroparasites as well as other macroscopic organisms.

  8. HALL CURRENT EFFECTS ON FREE CONVECTION MHD FLOW PAST A POROUS PLATE

    Directory of Open Access Journals (Sweden)

    G. Ramireddy

    2011-06-01

    Full Text Available Heat and mass transfer along a vertical porous plate under the combined buoyancy force effects of thermal and species diffusion is investigated in the presence of a transversely applied uniform magnetic field and the Hall currents are taken into account. The governing fundamental equations on the assumption of a small magnetic Reynolds number are approximated by a system of non-linear ordinary differential equations, which are integrated by fourth-order Runge–Kutta method. Velocity, temperature and concentration are shown on graphs. The numerical values of the local shear stress, the local Nusselt number Nu and the local Sherwood number Sh are entered in tables. The effects of the magnetic parameter, Hall parameter and the relative buoyancy force effect between species and thermal diffusion on the velocity, temperature and concentration are discussed. The results are compared with those known from the literature.

  9. Micromagnetic analysis of current-driven domain wall motion of multi-bit in a nanowire with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Hiroshi; Takahashi, Kouta; Komine, Takashi; Sugita, Ryuji, E-mail: komine@mx.ibaraki.ac.j [4-12-1 Nakanarusawa, Hitachi, Ibaraki 316-8511, Ibaraki University (Japan)

    2010-01-01

    The current-driven domain wall motion of a multi-bit in a magnetic nanowire with perpendicular magnetic anisotropy has been analyzed by performing a micromagnetic simulation. The multi-bit motion is determined by the applied current density and the non-adiabatic spin torque parameters, which is similar to the current-driven domain wall motion of the single wall. Consequently, it was found that are two modes in the multi-bit motion: (a) the bit length remains constant and (b) the bit length varies or the bit vanishes in the nanowire. It was found that these modes of the multi-bit motion can be classified by the critical current density or Walker breakdown for the single wall motion in a magnetic nanowire with perpendicular magnetic anisotropy.

  10. Effect of Joule heating in current-driven domain wall motion

    Science.gov (United States)

    Yamaguchi, A.; Nasu, S.; Tanigawa, H.; Ono, T.; Miyake, K.; Mibu, K.; Shinjo, T.

    2005-01-01

    It was found that high current density needed for the current-driven domain wall motion results in the Joule heating of the sample. The sample temperature, when the current-driven domain wall motion occurred, was estimated by measuring the sample resistance during the application of a pulsed current. The sample temperature was 750 K for the threshold current density of 6.7×1011A/m2 in a 10-nm-thick Ni81Fe19 wire with a width of 240 nm on thermally oxidized silicon substrate. The temperature was raised to 830 K for the current density of 7.5×1011A/m2, which is very close to the Curie temperature of bulk Ni81Fe19. When the current density exceeded 7.5×1011A/m2, an appearance of a multidomain structure in the wire was observed by magnetic force microscopy, suggesting that the sample temperature exceeded the Curie temperature.

  11. ac current generation in chiral magnetic insulators and Skyrmion motion induced by the spin Seebeck effect.

    Science.gov (United States)

    Lin, Shi-Zeng; Batista, Cristian D; Reichhardt, Charles; Saxena, Avadh

    2014-05-09

    We show that a temperature gradient induces an ac electric current in multiferroic insulators when the sample is embedded in a circuit. We also show that a thermal gradient can be used to move magnetic Skyrmions in insulating chiral magnets: the induced magnon flow from the hot to the cold region drives the Skyrmions in the opposite direction via a magnonic spin transfer torque. Both results are combined to compute the effect of Skyrmion motion on the ac current generation and demonstrate that Skyrmions in insulators are a promising route for spin caloritronics applications.

  12. Current noise spectra and mechanisms with dissipaton equation of motion theory

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Jinshuang [Department of Physics, Hangzhou Normal University, Hangzhou, Zhejiang 310036 (China); Wang, Shikuan [Department of Physics, Hangzhou Dianzi University, Hangzhou 310018 (China); Zheng, Xiao [Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Yan, YiJing, E-mail: yyan@ust.hk [Hefei National Laboratory for Physical Sciences at the Microscale and iChEM, University of Science and Technology of China, Hefei, Anhui 230026 (China); Department of Chemistry, Hong Kong University of Science and Technology, Hong Kong (China)

    2015-06-21

    Based on the Yan’s dissipaton equation of motion (DEOM) theory [J. Chem. Phys. 140, 054105 (2014)], we investigate the characteristic features of current noise spectrum in several typical transport regimes of a single-impurity Anderson model. Many well-known features such as Kondo features are correctly recovered by our DEOM calculations. More importantly, it is revealed that the intrinsic electron cotunneling process is responsible for the characteristic signature of current noise at anti-Stokes frequency. We also identify completely destructive interference in the noise spectra of noninteracting systems with two degenerate transport channels.

  13. On the motion and geometry of the Sierra Nevada Great Valley micro-plate: Implications for Walker Lane tectonics

    Science.gov (United States)

    Kreemer, C.; Hammond, W. C.; Blewitt, G.

    2006-12-01

    The Sierra Nevada Great Valley (SNGV) micro-plate, a.k.a. the Fresno block, has long been recognized as a tectonically stable entity within the Pacific North America plate boundary zone. Some early geodetic studies have confirmed and defined its rigid behavior. However, those studies were based on a very limited amount of geodetic station velocities, and were unable to assess the extent of rigidity towards the edges of the block. The San Andreas and Garlock fault systems define the western and southern edges of the block, but no such features are readily recognizable to the north and east, along the Walker Lane belt. A better assessment of the location of the boundary or transition between the stable SNGV block and the Walker Lane is important for three reasons. It will provide a better understanding of what controls Walker Lane development and evolution, it will provide important boundary conditions in understanding the present-day kinematics of the Walker Lane, and it is contributes to the assessment of seismic hazard levels for the Reno-Carson City area. We analyze data from all the available GPS sites in the greater SNGV region, including data from the SCIGN, BARD and BARGEN networks, semi-continuous data from our own MAGNET network, and campaign-style data (e.g., USGS, SCEC). Also we have started to analyze regional PBO sites, however time-series for most of those sites are at present too short to infer reliable velocity estimates. We use the GIPSY OASIS II software which employs precise point positioning using dual-frequency carrier phase and pseudorange data, and the precise orbit, clock, and reference frame transformation products publicly available from JPL. The analysis includes carrier phase ambiguity resolution and regional filtering. Using these velocities we perform a kinematic analysis of the station velocity solution, solving for an angular velocity that best describes the motion of the SNGV. We analyze the residuals to investigate where the SNGV

  14. Current Evidence: Plate Versus Intramedullary Nail for Fixation of Distal Tibia Fractures in 2016.

    Science.gov (United States)

    Vallier, Heather A

    2016-11-01

    Displaced distal tibia shaft fractures are effectively treated with standard plates and intramedullary nails. Plate fixation performed with meticulous soft tissue handling results in minimal risks of infection and poor wound healing. Standard plates have high rates of primary union, whereas locking plates may delay union because of increased stiffness. Tibial healing may also be delayed after plating of the fibula, although fibula reduction and fixation may aid accuracy of reduction of the tibia. Malalignment occurs more often with infrapatellar intramedullary nailing versus plates, and early results of suprapatellar nailing appear promising in minimizing intraoperative malalignment. Long-term function after fixation of the distal tibia is good for most, with poor outcomes often associated with baseline social and mental health issues.

  15. Influence of exchange coupling on current-driven domain wall motion in a nanowire

    Energy Technology Data Exchange (ETDEWEB)

    Komine, Takashi, E-mail: komine@mx.ibaraki.ac.j [Department of Media and Telecommunications Engineering, Ibaraki University, Ibaraki 316-8511 (Japan); Takahashi, Kota; Murakami, Hiroshi; Sugita, Ryuji [Department of Media and Telecommunications Engineering, Ibaraki University, Ibaraki 316-8511 (Japan)

    2010-10-15

    In this study, the effect of exchange stiffness constant on current-driven domain wall motion in nanowires with in-plane magnetic anisotropy (IMA) and perpendicular magnetic anisotropy (PMA) has been investigated using micromagnetic simulation. The critical current density in a nanowire with IMA decreases as the exchange stiffness constant decreases because the domain wall width at the upper edge of the nanowire narrows according to the decrease of the exchange stiffness constant. On the other hand, the critical current density in a nanowire with PMA slightly decreases contrary to that of IMA although the domain wall width reasonably decreases as the exchange stiffness constant decreases. The slight reduction rate of the critical current density is due to the increase of the effective hard-axis anisotropy of PMA nanowire.

  16. Two-dimensional laser servoing for precision motion control of an ODV robotic license plate recognition system

    Science.gov (United States)

    Song, Zhen; Moore, Kevin L.; Chen, YangQuan; Bahl, Vikas

    2003-09-01

    As an outgrowth of series of projects focused on mobility of unmanned ground vehicles (UGV), an omni-directional (ODV), multi-robot, autonomous mobile parking security system has been developed. The system has two types of robots: the low-profile Omni-Directional Inspection System (ODIS), which can be used for under-vehicle inspections, and the mid-sized T4 robot, which serves as a ``marsupial mothership'' for the ODIS vehicles and performs coarse resolution inspection. A key task for the T4 robot is license plate recognition (LPR). For a successful LPR task without compromising the recognition rate, the robot must be able to identify the bumper locations of vehicles in the parking area and then precisely position the LPR camera relative to the bumper. This paper describes a 2D-laser scanner based approach to bumper identification and laser servoing for the T4 robot. The system uses a gimbal-mounted scanning laser. As the T4 robot travels down a row of parking stalls, data is collected from the laser every 100ms. For each parking stall in the range of the laser during the scan, the data is matched to a ``bumper box'' corresponding to where a car bumper is expected, resulting in a point cloud of data corresponding to a vehicle bumper for each stall. Next, recursive line-fitting algorithms are used to determine a line for the data in each stall's ``bumper box.'' The fitting technique uses Hough based transforms, which are robust against segmentation problems and fast enough for real-time line fitting. Once a bumper line is fitted with an acceptable confidence, the bumper location is passed to the T4 motion controller, which moves to position the LPR camera properly relative to the bumper. The paper includes examples and results that show the effectiveness of the technique, including its ability to work in real-time.

  17. Current induced domain wall motion in nanostripes with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Su Jung; Tan, Reasmey P.; Chun, Byong Sun [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Kim, Young Keun, E-mail: ykim97@korea.ac.k [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of)

    2010-11-15

    We report micromagnetic modeling results of current induced domain wall (DW) motion in magnetic devices with perpendicular magnetic anisotropy by solving the Landau-Lifschitz-Gilbert equation including adiabatic and non-adiabatic terms. A nanostripe model system with dimensions of 500 nm (L)x25 nm (W)x5 nm (H) was selected for calculating the DW motion and its width, as a function of various parameters such as non-adiabatic contribution, anisotropy constant (K{sub u}), saturation magnetization (M{sub s}), and temperature (T). The DW velocity was found to increase when the values of K{sub u} and T were increased and the M{sub s} value decreased. In addition, a reduction of the domain wall width could be achieved by increasing K{sub u} and lowering M{sub s} values regardless of the non-adiabatic constant value.

  18. Universal current-velocity relation of skyrmion motion in chiral magnets

    Science.gov (United States)

    Iwasaki, Junichi; Mochizuki, Masahito; Nagaosa, Naoto

    2013-03-01

    Current-driven motion of the magnetic domain wall requires large critical current density jc ~109 -1012 A/m2, at which the joule heating is a serious problem. The skyrmions recently discovered in chiral magnets, on the other hand, have much smaller critical current of jc ~105 -106 A/m2. We present a numerical simulation of the Landau-Lifshitz-Gilbert equation, which reveals a remarkably robust and universal current-velocity relation of the slyrmion motion driven by the spin transfer torque unaffected by either impurities or nonadiabatic effect in sharp contrast to the case of domain wall or spin helix (HL). Simulation results are analyzed using a theory based on Thiele's equation, and it is concluded that this surprising behavior is due to the Magnus force and flexible shape-deformation of individual skyrmions and skyrmion crystal (SkX), which enable them to avoid pinning centers and then weaken the net pinning force. Dynamical deformation of SkX leads to the fluctuation of Bragg peak with large amplitude, which can be detected by the recent neutron-scattering experiment.

  19. HEAT AND MASS TRANSFER EFFECTS ON FLOW PAST PARABOLIC STARTING MOTION OF ISOTHERMAL VERTICAL PLATE IN THE PRESENCE OF FIRST ORDER CHEMICAL REACTION

    Directory of Open Access Journals (Sweden)

    R. Muthucumaraswamy

    2013-06-01

    Full Text Available An exact solution of unsteady flow past a parabolic starting motion of the infinite isothermal vertical plate with uniform mass diffusion, in the presence of a homogeneous chemical reaction of the first order, has been studied. The plate temperature and the concentration level near the plate are raised uniformly. The dimensionless governing equations are solved using the Laplace transform technique. The effect of velocity profiles are studied for different physical parameters, such as chemical reaction parameter, thermal Grashof number, mass Grashof number, Schmidt number, and time. It is observed that velocity increases with increasing values of thermal Grashof number or mass Grashof number. The trend is reversed with respect to the chemical reaction parameter.

  20. Current accumulation at an asymmetric 3D null point caused by generic shearing motions

    Science.gov (United States)

    Galsgaard, K.; Pontin, D. I.

    2011-10-01

    Context. Here we investigate the dynamical evolution of the reconnection process at an initially linear 3D null point that is stressed by a localised shear motion across the spine axis. The difference to previous investigations is that the fan plane is not rotationally symmetric and this allows for different behaviours depending on the alignment of the fan plane relative to the imposed driver direction. Aims: The aim is to show how the current accumulation and the associated reconnection process at the non-axisymmetric null depends on the relative orientation between the driver imposed stress across the spine axis of the null and the main eigenvector direction in the fan plane. Methods: The time evolution of the 3D null point is investigated solving the 3D non-ideal MHD equations numerically in a Cartesian box. The magnetic field is frozen to the boundaries and the boundary velocity is only non-zero where the imposed driving for stressing the system is applied. Results: The current accumulation is found to be along the direction of the fan eigenvector associated with the smallest eigenvalue until the direction of the driver is almost parallel to this eigenvector. When the driving velocity is parallel to the weak eigenvector and has an impulsive temporal profile the null only has a weak collapse forming only a weak current layer. However, when the null point is stressed continuously boundary effects dominates the current accumulation. Conclusions: There is a clear relation between the orientation of the current concentration and the direction of the fan eigenvector corresponding to the small eigenvalue. This shows that the structure of the magnetic field is the most important in determining where current is going to accumulate when a single 3D null point is perturbed by a simple shear motion across the spine axis. As the angle between the driving direction and the strong eigenvector direction increases, the current that accumulates at the null becomes progressively

  1. Development of eddy current testing probe for thick-walled metal plate and quantitative evaluation of cracks

    CERN Document Server

    Sato, K; Uchimoto, T; Takagi, T

    2003-01-01

    This paper demonstrates the crack detection of thick-walled non-magnetic metal plates by eddy current testing, which is difficult because of Kelvin skin effect generally. The purpose of this research is the development of an new eddy current testing probe for cracks in thick-walled plates and crack shapes quantitative evaluation. The probe was designed, based on the numerical computation using 3D fast eddy current code. The advantages of this new probe are strong eddy current on the back of specimens and gentle decrement of eddy current in the thickness direction. Through experiments, we confirmed that this probe can detect the back artificial defect with 0.5 mm thickness on IN-CONEL 718 specimen with 7.0 mm thickness. Reconstruction of crack shapes was performed based on the experimental results with the inverse problem code developed by authors. The length and depth of reconstructed defects approximately agree with those of real crack. (author)

  2. Wave Motion in an Ice Covered Ocean Due to Small Oscillations of a Submerged Thin Vertical Plate

    Institute of Scientific and Technical Information of China (English)

    Paramita Maiti; Puspendu Rakshit; Sudeshna Banerjea

    2015-01-01

    In this paper we study the problem of generation of surface waves produced due to a) rolling of the plate and b) presence of a line source in front of a fixed vertical plate. The amplitudes of radiated waves at large distance from the plate, in both cases, are obtained by a suitable application of Green’s integral theorem. These are then studied graphically for various values of the ice cover parameter.

  3. Composition and Morphology of Zn-Co Alloy Coatings Deposited by Means of Pulse Plating Containing Reverse Current

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The influence of bath constituents and pulse parameters on cobalt content, surface morphologies and grain size of Zn-Co alloy deposits was studied using a pulse plating technique with a squarewave current containing reverse pulse. It is found that Zn-Co alloy coatings obtained from the bath with the cobalt ion concentration over 60 wt% have a higher cobalt content in deposits. The results of pulse plating show that the average current density and reverse anodic current density amongst the variables investigated have very strong effects on the cobalt content in the Zn-Co alloy deposits. It is possible to electrodeposit Zn-Co alloy coatings with 10-90 wt% cobalt by modulating pulse parameters. The grain size, surface appearance and internal stress in the deposit were improved significantly by introducing the reverse current.

  4. Current-driven vortex domain wall motion in wire-tube nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Espejo, A. P. [Departamento de Física, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago (Chile); Institute of Nanostructure and Solid State Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg (Germany); Vidal-Silva, N. [Departamento de Física, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago (Chile); López-López, J. A. [Departamento de Física, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Goerlitz, D.; Nielsch, K. [Institute of Nanostructure and Solid State Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg (Germany); Escrig, J. [Departamento de Física, Universidad de Santiago de Chile (USACH), Av. Ecuador 3493, 9170124 Santiago (Chile); Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Av. Ecuador 3493, 9170124 Santiago (Chile)

    2015-03-30

    We have investigated the current-driven domain wall motion in nanostructures comprised of a pair of nanotube and nanowire segments. Under certain values of external magnetic fields, it is possible to pin a vortex domain wall in the transition zone between the wire and tube segments. We explored the behavior of this domain wall under the action of an electron flow applied in the opposite direction to the magnetic field. Thus, for a fixed magnetic field, it is possible to release a domain wall pinned simply by increasing the intensity of the current density, or conversely, for a fixed current density, it is possible to release the domain wall simply decreasing the magnetic external field. When the domain wall remains pinned due to the competition between the current density and the magnetic external field, it exhibits a oscillation frequency close to 8 GHz. The amplitude of the oscillations increases with the current density and decreases over time. On the other hand, when the domain wall is released and propagated through the tube segment, this shows the standard separation between a steady and a precessional regime. The ability to pin and release a domain wall by varying the geometric parameters, the current density, or the magnetic field transforms these wire-tube nanostructures in an interesting alternative as an on/off switch nano-transistor.

  5. Dissipation in thin superconducting current biased films due to vortex motion

    Energy Technology Data Exchange (ETDEWEB)

    Bulaevskii, Lev N [Los Alamos National Laboratory

    2009-01-01

    Recently, the problem of dissipation in thin superconducting films with thickness d on the order of the coherence length {zeta}, and width {omega} much narrower than the Pearl length, {Lambda} >> {omega} >> {zeta}, was discussed as the main cause for the behavior of I-V characteristics observed in thin high-temperature superconducting films. In thin and narrow films or strips with width w >> {zeta} the barrier for phase slips by creation of temporary normal regions across the entire film width is too big, thus phase slips become highly improbable. Instead, we consider a vortex crossing the strip from one edge to the other, perpendicular to the bias current, as the dominant mechanism for generalized phase slips resulting in detectable voltage pulses. We derive the rate of vortex crossings using the general theory of transition rates between metastable states. In mean field theory, the saddle point solution of the rate equation gives the vortex position inside the strip, where the kinetic energy of supercurrents is maximum. However, the free energy barrier derived in such an approach is strongly renormalized by superconducting fluctuations and this effect was not accounted for previously. They drastically reduce the rate of vortex crossings and, consequently, dissipation. We present results for the amplitude and duration of voltage pulses induced by vortex motion and their consequences on I-V characteristics, when heating due to vortex crossings is negligible. We found ohmic behavior at low bias currents, power law behavior at intermediate currents and exponential I-V characteristics at currents close to the critical one. The impact of vortex motion in superconducting strips on the observation of so-called dark counts (voltage pulses) in superconducting nanowire single-photon detectors is discussed.

  6. Effects of Hall current, radiation and rotation on natural convection heat and mass transfer flow past a moving vertical plate

    Directory of Open Access Journals (Sweden)

    G.S. Seth

    2014-06-01

    Full Text Available An investigation of the effects of Hall current and rotation on unsteady hydromagnetic natural convection flow with heat and mass transfer of an electrically conducting, viscous, incompressible and optically thick radiating fluid past an impulsively moving vertical plate embedded in a fluid saturated porous medium, when temperature of the plate has a temporarily ramped profile, is carried out. Exact solution of the governing equations is obtained in closed form by Laplace transform technique. Exact solution is also obtained in case of unit Schmidt number. Expressions for skin friction due to primary and secondary flows and Nusselt number are derived for both ramped temperature and isothermal plates. Expression for Sherwood number is also derived. The numerical values of primary and secondary fluid velocities, fluid temperature and species concentration are displayed graphically whereas those of skin friction are presented in tabular form for various values of pertinent flow parameters.

  7. Combined plate motion and density driven flow in the asthenosphere beneath Saudi Arabia: Evidence from shear-wave splitting and seismic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, S; Schwartz, S

    2006-02-08

    A comprehensive study of mantle anisotropy along the Red Sea and across Saudi Arabia was performed by analyzing shear-wave splitting recorded by stations from three different seismic networks: the largest, most widely distributed array of stations examined across Saudi Arabia to date. Stations near the Gulf of Aqaba display fast orientations that are aligned parallel to the Dead Sea Transform Fault, most likely related to the strike-slip motion between Africa and Arabia. However, most of our observations across Saudi Arabia are statistically the same, showing a consistent pattern of north-south oriented fast directions with delay times averaging about 1.4 s. Fossilized anisotropy related to the Proterozoic assembly of the Arabian Shield may contribute to the pattern but is not sufficient to fully explain the observations. We feel that the uniform anisotropic signature across Saudi Arabia is best explained by a combination of plate and density driven flow in the asthenosphere. By combining the northeast oriented flow associated with absolute plate motion with the northwest oriented flow associated with the channelized Afar plume along the Red Sea, we obtain a north-south oriented resultant that matches our splitting observations and supports models of active rifting processes. This explains why the north-south orientation of the fast polarization direction is so pervasive across the vast Arabian Plate.

  8. A pulsed eddy current probe for inspection of support plates from within Alloy-800 steam generator tubes

    Energy Technology Data Exchange (ETDEWEB)

    Krause, T. W.; Babbar, V. K.; Underhill, P. R. [Department of Physics, Royal Military College of Canada, Kingston, ON (Canada)

    2014-02-18

    Support plate degradation and fouling in nuclear steam generators (SGs) can lead to SG tube corrosion and loss of efficiency. Inspection and monitoring of these conditions can be integrated with preventive maintenance programs, thereby advancing station-life management processes. A prototype pulsed eddy current (PEC) probe, targeting inspection issues associated with SG tubes in SS410 tube support plate structures, has been developed using commercial finite element (FE) software. FE modeling was used to identify appropriate driver and pickup coil configurations for optimum sensitivity to changes in gap and offset for Alloy-800 SG tubes passing through 25 mm thick SS410 support plates. Experimental measurements using a probe that was manufactured based on the modeled configuration, were used to confirm the sensitivity of differential PEC signals to changes in relative position of the tube within the tube support plate holes. Models investigated the effect of shift and tilt of tube with respect to hole centers. Near hole centers and for small shifts, modeled signal amplitudes from the differentially connected coil pairs were observed to change linearly with tube shift. This was in agreement with experimentally measured TEC coil response. The work paves the way for development of a system targeting the inspection and evaluation of support plate structures in steam generators.

  9. A pulsed eddy current probe for inspection of support plates from within Alloy-800 steam generator tubes

    Science.gov (United States)

    Krause, T. W.; Babbar, V. K.; Underhill, P. R.

    2014-02-01

    Support plate degradation and fouling in nuclear steam generators (SGs) can lead to SG tube corrosion and loss of efficiency. Inspection and monitoring of these conditions can be integrated with preventive maintenance programs, thereby advancing station-life management processes. A prototype pulsed eddy current (PEC) probe, targeting inspection issues associated with SG tubes in SS410 tube support plate structures, has been developed using commercial finite element (FE) software. FE modeling was used to identify appropriate driver and pickup coil configurations for optimum sensitivity to changes in gap and offset for Alloy-800 SG tubes passing through 25 mm thick SS410 support plates. Experimental measurements using a probe that was manufactured based on the modeled configuration, were used to confirm the sensitivity of differential PEC signals to changes in relative position of the tube within the tube support plate holes. Models investigated the effect of shift and tilt of tube with respect to hole centers. Near hole centers and for small shifts, modeled signal amplitudes from the differentially connected coil pairs were observed to change linearly with tube shift. This was in agreement with experimentally measured TEC coil response. The work paves the way for development of a system targeting the inspection and evaluation of support plate structures in steam generators.

  10. GPS Measurements of Crustal Deformation in Lebanon: Implication for Current Kinematics of the Sinaï Plate.

    Science.gov (United States)

    Vergnolle, M.; Jomaa, R.; Brax, M.; Menut, J. L.; Sursock, A.; Elias, A. R.; Mariscal, A.; Vidal, M.; Cotte, N.

    2016-12-01

    The Levant fault is a major strike-slip fault bounding the Arabia and the Sinaï plates. Its kinematics, although understood in its main characteristics, remains partly unresolved in its quantification, especially in the Lebanese restraining bend. We present a GPS velocity field based on survey GPS data acquired in Lebanon (1999, 2002, 2010) and on continuous GPS data publicly available in the Levant area. To complete the measurements along the Levant fault, we combine our velocity field with previously published velocity fields. First, from our velocity field, we derive two velocity profiles, across the Lebanese fault system, which we analyze in terms of elastic strain accumulation. Despite the uncertainty on the locking depth of the main strand of the Levant fault, small lateral fault slip rates (2-4mm/yr) are detected on each profile, with a slight slip rate decrease (Lebanon. Small compression (Lebanon, is also suggested. Second, we analyze the combined GPS velocity field in the Sinaï tectonic framework. We evaluate how well the Sinaï plate motion is described with an Euler pole. Due to heterogeneous velocity errors (5 times smaller for cGPS velocities wrt sGPS velocities), a unique pole estimation using all the data provides good statistical results. However, the residuals show systematic deviations at central and northern sGPS stations. Using only the velocities at these stations, the estimated pole is significantly different from the unique pole at 95% confidence level. This analysis highlights the difficulty to robustly resolve the rigid Sinaï plate motion while the uncertainties on the velocities are heterogeneous. New sGPS measurements on existing sites should improve the solution and help to conclude.

  11. Reducing Postoperative Fracture Displacement After Locked Plating of Proximal Humerus Fractures: Current Concepts.

    Science.gov (United States)

    Newman, Jared; Kahn, Mani; Gruson, Konrad I

    2015-07-01

    The incidence of proximal humerus fractures in the elderly has been rising. Concomitantly, operative fixation with use of locking plates has been increasing. Postoperative complications of locking plate fixation, particularly in the setting of osteoporotic bone, include screw penetration of the articular surface, progressive fracture displacement, and avascular necrosis. Intraoperative techniques to enhance the fixation construct and reduce complications include use of rotator cuff sutures, bone void fillers (fibular strut allograft, cancellous allograft, autograft, bone cement), appropriate placement of divergent and shorter locking screws, and medial calcar reduction and support. More recent clinical and biomechanical studies suggest that use of these strategies may reduce complications after locked plating of osteoporotic proximal humerus fractures. Furthermore, a multidisciplinary approach to the evaluation and treatment of osteoporosis may be beneficial in these patients.

  12. Magma production rate along the Ninetyeast Ridge and its relationship to Indian plate motion and Kerguelen hot spot activity

    Digital Repository Service at National Institute of Oceanography (India)

    Sreejith, K.M.; Krishna, K.S.

    The Ninetyeast Ridge, a linear trace of the Kerguelen hot spot in the Indian Ocean, was emplaced on a rapidly drifting Indian plate. Magma production rates along the ridge track are computed using gravity-derived excess crustal thickness data...

  13. Numerical solution of the problem on the constant current flow around a dielectric plate

    Energy Technology Data Exchange (ETDEWEB)

    Stadnik, I.P.

    1977-01-01

    The problem of a harmonic field circumvention of a plate of arbitrary form is reduced to a second species integral equation for the density of a binary layer. A feature of this integral equation is that the integration is performed along the entire plate except the circle contained in the center of the observation point. The method's agreement with sequential approximations is proven. An examination is made of the plane-parallel case and an example illustrating good agreement in results for the plane-parallel case which were obtained by the proposed method and method of conformal depictions. 2 references, 4 figures.

  14. The Plate Boundary Observatory: Current status and plans for the next five years

    Science.gov (United States)

    Mattioli, G. S.; Feaux, K.; Meertens, C. M.; Mencin, D.; Miller, M.

    2013-12-01

    UNAVCO currently operates and maintains the NSF-funded Plate Boundary Observatory (PBO), which is the geodetic facility of EarthScope. PBO was designed and built from 2003 to 2008 with $100M investment from the NSF Major Research Equipment and Facilities Construction (MREFC) Program. UNAVCO operated and maintained PBO under a Cooperative Agreement (CA) with NSF from 2008 to 2013 and will continue PBO O&M for the next five years as part of the new Geodesy Advancing Geosciences and EarthScope (GAGE) Facility. PBO is largest continuous GPS and borehole geophysical network in the Americas, with 1100 continuous Global Positioning System (cGPS) sites, including several with multiple monuments, 79 boreholes, with 75 tensor strainmeters, 78 short-period, 3-component seismometers, and pore pressure sensors at 23 sites. PBO also includes 26 tiltmeters deployed at volcanoes in Alaska, Mt St Helens, and Yellowstone caldera and 6 long-baseline laser strainmeters. Surface meteorological sensors are collocated at 154 GPS sites. UNAVCO provides high-rate (1 Hz), low-latency (streams (RT-GPS) from 382 stations in PBO. UNAVCO has delivered over 62 Tb of geodetic data to the EarthScope community since its PBO's inception in 2004. Over the past year, data return for the cGPS component of PBO is 98%, well above the data return metric of 85% set by the NSF, a result of efforts to upgrade power systems and communications infrastructure. In addition, PBO has set the standard for the design, construction, and operation of other multi-hazard networks across the Americas, including COCONet in the Caribbean region and TLALOCNet in Mexico. Funding to support ongoing PBO O&M has declined from FY2012 CA levels under the new GAGE Facility. The implications for data return and data quality metrics as well as replacement of aging PBO GPS instruments with GNSS-compatible systems are as yet unknown. A process to assess the cost of specific PBO components, data rates, enhanced capabilities, and method

  15. Identification and Estimation of Postseismic Deformation: Implications for Plate Motion Models, Models of the Earthquake Cycle, and Terrestrial Reference Frame Definition

    Science.gov (United States)

    Kedar, S.; Bock, Y.; Moore, A. W.; Argus, D. F.; Fang, P.; Liu, Z.; Haase, J. S.; Su, L.; Owen, S. E.; Goldberg, D.; Squibb, M. B.; Geng, J.

    2015-12-01

    Postseismic deformation indicates a viscoelastic response of the lithosphere. It is critical, then, to identify and estimate the extent of postseismic deformation in both space and time, not only for its inherent information on crustal rheology and earthquake physics, but also since it must considered for plate motion models that are derived geodetically from the "steady-state" interseismic velocities, models of the earthquake cycle that provide interseismic strain accumulation and earthquake probability forecasts, as well as terrestrial reference frame definition that is the basis for space geodetic positioning. As part of the Solid Earth Science ESDR System) SESES project under a NASA MEaSUREs grant, JPL and SIO estimate combined daily position time series for over 1800 GNSS stations, both globally and at plate boundaries, independently using the GIPSY and GAMIT software packages, but with a consistent set of a prior epoch-date coordinates and metadata. The longest time series began in 1992, and many of them contain postseismic signals. For example, about 90 of the global GNSS stations out of more than 400 that define the ITRF have experienced one or more major earthquakes and 36 have had multiple earthquakes; as expected, most plate boundary stations have as well. We quantify the spatial (distance from rupture) and temporal (decay time) extent of postseismic deformation. We examine parametric models (log, exponential) and a physical model (rate- and state-dependent friction) to fit the time series. Using a PCA analysis, we determine whether or not a particular earthquake can be uniformly fit by a single underlying postseismic process - otherwise we fit individual stations. Then we investigate whether the estimated time series velocities can be directly used as input to plate motion models, rather than arbitrarily removing the apparent postseismic portion of a time series and/or eliminating stations closest to earthquake epicenters.

  16. Current driven domain wall motion in rare-earth transition metal alloys with perpendicular magnetic anisotropy.

    Science.gov (United States)

    Li, Songtian; Liu, Xiaoxi; Morisako, Akimistu

    2012-09-01

    The domain wall movement behaviors under current combining with magnetic field in perpendicularly magnetized TbFeCo wire were studied by a polar magneto-optical Kerr effect microscope. The velocity for domain wall creeping along electrons flowing direction was found to be apparently higher than that of domain wall creeping against electrons flowing, which is the signature of the spin transfer torque effect. By employing the modified field-driven creep motion law, a spin transfer efficiency of 2.7 Oe cm2/10(6) A was determined for TbFeCo wire by treating the spin transfer torque as an effective field adding to the external field. The high spin transfer efficiency suggests that perpendicularly magnetized system with sharp domain walls in TbFeCo film shows high superiorities for applications in spin transfer torque based devices compared with in-plane magnetized systems.

  17. Role of spin diffusion in current-induced domain wall motion for disordered ferromagnets

    KAUST Repository

    Akosa, Collins Ashu

    2015-03-12

    Current-induced spin transfer torque and magnetization dynamics in the presence of spin diffusion in disordered magnetic textures is studied theoretically. We demonstrate using tight-binding calculations that weak, spin-conserving impurity scattering dramatically enhances the nonadiabaticity. To further explore this mechanism, a phenomenological drift-diffusion model for incoherent spin transport is investigated. We show that incoherent spin diffusion indeed produces an additional spatially dependent torque of the form ∼∇2[m×(u⋅∇)m]+ξ∇2[(u⋅∇)m], where m is the local magnetization direction, u is the direction of injected current, and ξ is a parameter characterizing the spin dynamics (precession, dephasing, and spin-flip). This torque, which scales as the inverse square of the domain wall width, only weakly enhances the longitudinal velocity of a transverse domain wall but significantly enhances the transverse velocity of vortex walls. The spatial-dependent spin transfer torque uncovered in this study is expected to have significant impact on the current-driven motion of abrupt two-dimensional textures such as vortices, skyrmions, and merons.

  18. Radiation induced currents in parallel plate ionization chambers: measurement and Monte Carlo simulation for megavoltage photon and electron beams.

    Science.gov (United States)

    Abdel-Rahman, Wamied; Seuntjens, Jan P; Verhaegen, Frank; Podgorsak, Ervin B

    2006-09-01

    Polarity effects in ionization chambers are caused by a radiation induced current, also known as Compton current, which arises as a charge imbalance due to charge deposition in electrodes of ionization chambers. We used a phantom-embedded extrapolation chamber (PEEC) for measurements of Compton current in megavoltage photon and electron beams. Electron contamination of photon beams and photon contamination of electron beams have a negligible effect on the measured Compton current. To allow for a theoretical understanding of the Compton current produced in the PEEC effect we carried out Monte Carlo calculations with a modified user code, the COMPTON/ EGSnrc. The Monte Carlo calculated COMPTON currents agree well with measured data for both photon and electron beams; the calculated polarity correction factors, on the other hand, do not agree with measurement results. The conclusions reached for the PEEC can be extended to parallel-plate ionization chambers in general.

  19. Temperature estimation in a ferromagnetic Fe-Ni nanowire involving a current-driven domain wall motion.

    Science.gov (United States)

    Yamaguchi, A; Hirohata, A; Ono, T; Miyajima, H

    2012-01-18

    We observed a magnetic domain wall (DW) motion induced by the spin-polarized pulsed current in a nanoscale Fe(19)Ni(81) wire using a magnetic force microscope. High current density, which is of the order of 10(11) A m(-2), was required for the DW motion. A simple method to estimate the temperature of the wire was developed by comparing the wire resistance measured during the DW motion with the temperature dependence of the wire resistance. Using this method, we found the temperature of the wire was proportional to the square of the current density and became just beneath at the threshold Curie temperature. Our experimental data qualitatively support this analytical model that the temperature is proportional to the resistivity, thickness, width of the wire and the square of the current density, and also inversely proportional to the thermal conductivity.

  20. Temperature dependence of carrier spin polarization determined from current-induced domain wall motion in a Co/Ni nanowire

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, K.; Koyama, T.; Hiramatsu, R.; Kobayashi, K.; Ono, T. [Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Chiba, D. [Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho Kawaguchi, Saitama 322-0012 (Japan); Fukami, S. [Green Innovation Research Laboratories, NEC Corporation, 34 Miyukigaoka, Tsukuba, Ibaraki 305-8501 (Japan); Center for Spintronics Integrated Systems, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Tanigawa, H.; Suzuki, T. [RENESAS Electronics Corporation, Sagamihara, Kanagawa 252-5298 (Japan); Ohshima, N. [NEC Energy Device Ltd., 1120 Shimokuzawa, Chuo-ku, Sagamihara, Kanagawa 252-5298 (Japan); Ishiwata, N. [Green Innovation Research Laboratories, NEC Corporation, 34 Miyukigaoka, Tsukuba, Ibaraki 305-8501 (Japan); Nakatani, Y. [University of Electro-communications, Chofu, Tokyo 182-8585 (Japan)

    2012-05-14

    We have investigated the temperature dependence of the current-induced magnetic domain wall (DW) motion in a perpendicularly magnetized Co/Ni nanowire at various temperatures and with various applied currents. The carrier spin polarization was estimated from the measured domain wall velocity. We found that it decreased more with increasing temperature from 100 K to 530 K than the saturation magnetization did.

  1. In vivo analysis of acromioclavicular joint motion after hook plate fixation using three-dimensional computed tomography.

    Science.gov (United States)

    Kim, Yoon Sang; Yoo, Yon-Sik; Jang, Seong Wook; Nair, Ayyappan Vijayachandran; Jin, Hyonki; Song, Hyun-Seok

    2015-07-01

    The clavicle hook plate can be used to treat acromioclavicular and coracoclavicular ligament injury or distal clavicular fracture with comminution. However, the hook plate can induce subacromial impingement, resulting in discomfort from the hardware. Our inclusion criteria were (1) men and women aged older than 20 years and (2) the presence of comminuted distal clavicular fractures (Neer type IIB) fixed with a hook plate (Synthes, Oberdorf, Switzerland). Three-dimensional computed tomography was obtained before removal of the hook plate. Seven patients were enrolled prospectively. The mean age was 42 years (range, 24-60 years). Zero degree images and abduction images were obtained. The sagittal cut surface was obtained 5 mm medial from the distal clavicle. The equator of the cut surface of the clavicle was compared with the full abduction model to analyze rotation. The center of the cut surface of the clavicle was compared with the full abduction model to analyze translation. The average difference in rotation of the distal clavicle between both shoulders was 16° (range, 3°-22°; P = .001). The mean difference in anterior translation of the distal clavicle was 2.2 mm (range, -0.7 to 5.6 mm; P = .030). Hook plate fixation at the acromioclavicular joint causes decreased internal rotation and increased anterior translation of the distal clavicle with respect to the medial acromion, indicating that the scapula relative to the thorax has decreased posterior tilting and increased external rotation in shoulders fixed using a hook plate. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  2. Accelerated plate tectonics.

    Science.gov (United States)

    Anderson, D L

    1975-03-21

    The concept of a stressed elastic lithospheric plate riding on a viscous asthenosphere is used to calculate the recurrence interval of great earthquakes at convergent plate boundaries, the separation of decoupling and lithospheric earthquakes, and the migration pattern of large earthquakes along an arc. It is proposed that plate motions accelerate after great decoupling earthquakes and that most of the observed plate motions occur during short periods of time, separated by periods of relative quiescence.

  3. Current accumulation at an asymmetric 3D null point caused by generic shearing motions

    CERN Document Server

    Galsgaard, Klaus

    2011-01-01

    Context. We investigate the dynamical evolution of the reconnection process at an initially linear 3D null point that is stressed by a localised shear motion across the spine axis. The fan plane is not rotationally symmetric and this allows for different behaviours depending on the alignment of the fan plane relative to the imposed driver direction. Aims. The aim is to show how the current accumulation and the associated reconnection process depends on the relative orientation between the driver imposed stress across the spine axis of the null and the main eigenvector direction in the fan plane. Methods. The time evolution of the 3D null point is investigated solving the 3D non-ideal MHD equations numerically in a Cartesian box. The magnetic field is frozen to the boundaries and the boundary velocity is only non-zero where the imposed driving is for stressing the system is applied. Results. The current accumulation is found to be along the direction of the fan eigenvector associated with the smallest eigenval...

  4. Foucault pendulum with eddy-current damping of the elliptical motion

    Science.gov (United States)

    Mastner, G.; Vokurka, V.; Maschek, M.; Vogt, E.; Kaufmann, H. P.

    1984-10-01

    A newly designed Foucault pendulum is described in which the mechanical Charron ring, used throughout in previous designs for damping of the elliptical motion of the pendulum, is replaced by an electromagnetic eddy-current brake, consisting of a permanent magnet attached to the bottom of the bob and a metallic ring. This damping device is very efficient, as it is self-aligning, symmetrical in the damping effect, and never wears out. The permanent magnet is also used, together with a coil assembly and an electronic circuitry, for the dipole-torque drive of the pendulum as well as for accurate stabilization of the amplitude of the swing. A latched time display, controlled by Hall probes activated by the magnet, is used to visualize the Foucault rotation. The pendulum system and its associated electronic circuitry are described in detail. The optimizing of the drive mode is discussed. Measurements of deviations from theoretical value of the Foucault rotation velocity made automatically in a continuous run show a reproducible accuracy of ±1% or better in individual 360° rotations during the summer months. The quality factor of the pendulum as mechanical resonator was measured as a function of the amplitude in the presence of the eddy-current damping ring.

  5. Large vertical motions and basin evolution in the Outer Continental Borderland off Southern California associated with plate boundary development and continental rifting

    Science.gov (United States)

    Nicholson, C.; Sorlien, C. C.; Schindler, C. S.; De Hoogh, G.

    2011-12-01

    The Continental Borderland offshore southern California occupies a strategic position along the continental margin. It was the locus of ~75% of Pacific-North America displacement history, it helped accommodate the large-scale (>90°) tectonic rotation of the Western Transverse Ranges province, and is still accommodating potentially 20% of PAC-NAM plate motion today. As such, it represents an ideal natural laboratory to investigate plate boundary evolution and basin development associated with transform initiation, oblique continental rifting, transrotation and transpression. We have been using newly released grids of high-quality industry multichannel seismic (MCS) reflection data, combined with multibeam bathymetry and offshore well data to map and construct digital 3D fault surfaces and stratigraphic reference horizons over large parts of the Outer Continental Borderland. These 3D surfaces of structure and stratigraphy can be used to better understand and evaluate regional patterns of uplift, subsidence, fault interaction and other aspects of plate boundary deformation. In the northern Outer Borderland, mapping in Santa Cruz basin, and across both Santa Rosa and Santa Cruz-Catalina ridges reveals a pattern of interacting high-and low-angle faults, fault reactivation, basin subsidence, folding, and basin inversion. Subsidence since early-Miocene time is significant (up to 4 km) and is much larger than predicted by simple thermal cooling models of continental rifting. This requires additional tectonic components to drive this regional subsidence and subsequent basin inversion. Farther south, a more en echelon pattern of ridges and basins suggests a distributed component of right-lateral shear also contributed to much of the modern Borderland seafloor topography, including major Borderland basins. Vertical motions of uplift and subsidence can be estimated from a prominent early-Miocene unconformity that likely represents a regional, paleo-horizontal, near

  6. Evaluation of plate type fuel elements by eddy current test method; Avaliacao de combustiveis nucleares tipo placa pelo metodo de correntes parasitas

    Energy Technology Data Exchange (ETDEWEB)

    Frade, Rangel Teixeira

    2015-07-01

    Plate type fuel elements are used in MTR research nuclear reactors. The fuel plates are manufactured by assembling a briquette containing the fissile material inserted in a frame, with metal plates in both sides of the set, to act as a cladding. This set is rolled under controlled conditions in order to obtain the fuel plate. In Brazil, this type of fuel is manufactured by IPEN and used in the IEA-R1 reactor. After fabrication of three batches of fuel plates, 24 plates, one of them is taken, in order to verify the thickness of the cladding. For this purpose, the plate is sectioned and the thickness measurements are carried out by using optical microscopy. This procedure implies in damage of the plate, with the consequent cost. Besides, the process of sample preparation for optical microscopy analysis is time consuming, it is necessary an infrastructure for handling radioactive materials and there is a generation of radioactive residues during the process. The objective of this study was verify the applicability of eddy current test method for nondestructive measurement of cladding thickness in plate type nuclear fuels, enabling the inspection of all manufactured fuel plates. For this purpose, reference standards, representative of the cladding of the fuel plates, were manufactured using thermomechanical processing conditions similar to those used for plates manufacturing. Due to no availability of fuel plates for performing the experiments, the presence of the plate’s core was simulated using materials with different electrical conductivities, fixed to the thickness reference standards. Probes of eddy current testing were designed and manufactured. They showed high sensitivity to thickness variations, being able to separate small thickness changes. The sensitivity was higher in tests performed on the reference standards and samples without the presence of the materials simulating the core. For examination of the cladding with influence of materials simulating the

  7. Detection of plating defects using ultrasonic and eddy current test methods; Nachweis von Plattierungsfehlern mit Ultraschall- und Wirbelstromverfahren

    Energy Technology Data Exchange (ETDEWEB)

    Waidele, H.; Knoch, P. [MPA, Univ. Stuttgart (Germany); Gersinska, R. [BfS Salzgitter (Germany); Brenner, W.; Seidenkranz, T. [TUeV Sued (Germany); Csapo, G.; Just, T. [TUeV Nord (Germany); Weiss, R. [IzfP Saarbruecken (Germany); Rathgeb, W. [IntelligeNDT, Erlangen (Germany)

    2004-07-01

    The validity of ultrasonic and eddy current testing of austenitic platings of reactor pressure vessels was investigated in the context of a project funded by the Federal Radiation Protection Office (Bundesamt fuer Strahlenschutz). In the first phase, test specimens with natural defects were fabricated at MPA Stuttgart; in the second phase, plating defects were introduced in a MPA large-size vessel. Measurements showed that most plating defects will be detected by standard ultrasonic testing. The highest accuracy was achieved by a combination of ultrasonic and eddy current testing. (orig.) [German] Im Rahmen eines vom Bundesamt fuer Strahlenschutz gefoerderten Vorhabens wurde die Aussagefaehigkeit von Ultraschall- und Wirbelstrompruefungen an austenitischen Plattierungen von Reaktordruckbehaeltern untersucht. In der ersten Phase des Vorhabens wurden an der MPA Stuttgart Testkoerper mit natuerlichen Fehlern im Plattierungsbereich gefertigt, in einer zweiten Phase wurden Plattierungsfehler in den MPA-Grossbehaelter eingebracht. Die Messungen haben gezeigt, dass die meisten Plattierungsfehler mit Ultraschall-Standardprueftechniken nachweisbar sind, wobei die groesste Aussagekraft bei einer Kombination von Ultraschall- und Wirbelstrompruefung gegeben ist. (orig.)

  8. Effect of direct current and pulse plating on the EDM performance of copper-zirconium diboride composites

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Direct current and pulse plating of copper-zirconium diboride (ZrB2) composites were studied and the effects of current density (DC) and pulse duty cycle (PC) on the EDM performance of the composites were investigated. With increasing current density, the effect of grain refinement on the electro-discharge machining (EDM) performance of the composites compensates that of the decrease of ZrB2 content in the composites, which improves the spark-resistance of the material. Under the same average current density and other experiment conditions, a lower duty cycle yields better EDM performance probably because more ZrB2 particles are incorporated in the composites in this condition. However, at a still lower duty cycle (10%), the particle agglomeration and the microcracks of the copper matrix occur, which considerably deteriorate the spark-resistance of the composites.

  9. Vibrations of twisted cantilevered plates - Summary of previous and current studies

    Science.gov (United States)

    Leissa, A. W.; Macbain, J. C.; Kielb, R. E.

    1984-01-01

    This work summarizes a comprehensive study made of the free vibrations of twisted, cantilevered plates of rectangular planform. Numerous theoretical and experimental investigations previously made by others have resulted in frequency results which disagree considerably. To clarify the problem a joint industry/government/university research effort was initiated to obtain comprehensive theoretical and experimental results for models having useful ranges of aspect ratios, thickness ratios and twist angles. Theoretical data came from 19 independent computer analyses, including finite element, shell theory and beam theory idealizations. Two independent sets of experimental data were also obtained. The theoretical and experimental results are summarized and compared.

  10. Topological dynamics and current-induced motion in a skyrmion lattice

    Science.gov (United States)

    Martinez, J. C.; Jalil, M. B. A.

    2016-03-01

    We study the Thiele equation for current-induced motion in a skyrmion lattice through two soluble models of the pinning potential. Comprised by a Magnus term, a dissipative term and a pinning force, Thiele’s equation resembles Newton’s law but in virtue of the topological character to the first, it differs significantly from Newtonian mechanics and because the Magnus force is dominant, unlike its mechanical counterpart—the Coriolis force—skyrmion trajectories do not necessarily have mechanical counterparts. This is important if we are to understand skyrmion dynamics and tap into its potential for data-storage technology. We identify a pinning threshold velocity for the one-dimensional pinning potential and for a two-dimensional attractive potential we find a pinning point and the skyrmion trajectories toward that point are spirals whose frequency (compare Kepler’s second law) and amplitude-decay depend only on the Gilbert constant and potential at the pinning point. Other scenarios, e.g. other choices of initial spin velocity, a repulsive potential, etc are also investigated.

  11. Arc Root Motions in an Argon-Hydrogen Direct-Current Plasma Torch at Reduced Pressure

    Institute of Scientific and Technical Information of China (English)

    HUANG He-Ji; PAN Wen-Xia; WU Cheng-Kang

    2008-01-01

    Arc root motions in generating dc argon hydrogen plasma at reduced pressure are optically observed using a high-speed video camera. The time resolved angular position of the arc root attachment point is measured and analysed. The arc root movement is characterized as a chaotic and jumping motion along the circular direction on the anode surface.

  12. Effect of a pinning field on the critical current density for current-induced domain wall motion in perpendicular magnetic anisotropy nanowires.

    Science.gov (United States)

    Ooba, Ayaka; Fujimura, Yuma; Takahashi, Kota; Komine, Takashi; Sugita, Ryuji

    2012-09-01

    In this study, the effect of a pinning field on the critical current density for current-induced domain wall motion in nanowires with perpendicular magnetic anisotropy was investigated using micromagnetic simulations. In order to estimate the pinning field in notched nanowires, we conducted wall energy calculations for nanowires with various saturation magnetizations. The pinning field increased as the notch size increased. The pinning field decreased as the saturation magnetization decreased. As a result, the decreased in the pinning field causes the reduction of the critical current density. Therefore, a significant reduction of the critical current density can be obtained by decreasing the saturation magnetization, even if wall pinning occurs.

  13. Jerks as Guiding Influences on the Global Environment: Effects on the Solid Earth, Its Angular Momentum and Lithospheric Plate Motions, the Atmosphere, Weather, and Climate

    Science.gov (United States)

    Quinn, J. M.; Leybourne, B. A.

    2010-12-01

    modulated. These parameters in turn affect the weather and climate (e.g., the Dust Bowl Era, El Ninos, La Ninas, and hurricanes). The stress/strain within the Earth leads to Earth torsion, vibration, and mass redistribution, which leads to tectonic plate motion, seismicity, volcanism, and gravity waves, which drive atmospheric circulation and the teleconnection processes (i.e., a redistribution of magma beneath the plates) via surge tectonics. Various other connections among these processes and parameters will be discussed.

  14. Direct observation of current-induced motion of a 3D vortex domain wall in cylindrical nanowires

    KAUST Repository

    Ivanov, Yurii P.

    2017-05-08

    The current-induced dynamics of 3D magnetic vortex domain walls in cylindrical Co/Ni nanowires are revealed experimentally using Lorentz microscopy and theoretically using micromagnetic simulations. We demonstrate that a spin-polarized electric current can control the reversible motion of 3D vortex domain walls, which travel with a velocity of a few hundred meters per second. This finding is a key step in establishing fast, high-density memory devices based on vertical arrays of cylindrical magnetic nanowires.

  15. Modelling of Current Density Redistribution in Hollow Needle to Plate Electrical Discharge Designed for Ozone Generation

    Science.gov (United States)

    Kriha, Vitezslav

    2003-10-01

    Non-thermal plasma of atmospheric pressure electrical discharges in flowing air can be used to generation of ozone. We have been observed two modes of discharge burning in a hollow needle to plane electrodes configuration studied in the ozone generation experiments: A low current diffuse mode is characterized by increasing of the ozone production with the discharge current; a high current filamentary mode is disadvantageous for the ozone generation(the ozone production decreases when the discharge current increases). A possible interpretation of this effect is following: The filamentary mode discharge current density is redistributed and high current densities in filaments cores lead to degradation of the ozone generation. Local fields in the discharge can be modified by charged metallic and/or dielectric components (passive modulators) in the discharge space. An interactive numerical model has been developed for this purpose. This model is based on Ferguson's polynomial objects for both the discharge chamber scene modelling and the discharge fields analyzing. This approach allows intuitive modifications of modulators shapes and positions in 3D scene followed by quantitative comparison of the current density distribution with previous configurations.

  16. The metallogenic role of east-west fracture zones in South America with regard to the motion of lithospheric plates (with an example from Brazil)

    Science.gov (United States)

    Kutina, J.; Carter, William D.; Lopez, F.X.

    1978-01-01

    The role of east-west fracture zones in South America is discussed with regard to global fracturing and the motion of lithospheric plates. A set of major NW-trending lineaments has been derived which show a tendency to be spaced equidistantly and may correspond to a set of east-west fractures in the "pre-drift" position of the South American plate. Statistical analysis of linears in the ERTS-mosaics shows that NW-fractures are also among the most important ones in the Andes region, suggesting that the above major lineaments extend into the basement of the Andes. Some of the old major fractures, trending east-west in the present orientation of South America, are discussed and their NE orientation in the pre-drift position of the plate is considered. An example of structural control of ore deposition in the Brazilian Shield is presented, using the maps of the RADAM Project. It is concluded that the small tin-bearing granitic bodies concentrated in the region of Sao Felix do Xingu in the state of Para represent upper parts of an unexposed granitoid massif which is controlled by the intersection of a major east-west fracture zone probably represents westward extension of the Patos Lineament of the easternmost part of Brazil, connected with the east-west fracture zone of the Para state through the basement of the Maranhao Basin (Sineclise do Maranhao-Piaui). It is expected that the proposed "Patos-Para Lineament" extends further westward and may similarly control, at intersections with fractures of other trends, some mineralization centers in the western part of the state of Para and in the state of Amazonas.

  17. Engineering applications and analysis of vibratory motion fourth order fluid film over the time dependent heated flat plate

    Science.gov (United States)

    Mohmand, Muhammad Ismail; Mamat, Mustafa Bin; Shah, Qayyum

    2017-07-01

    This article deals with the time dependent analysis of thermally conducting and Magneto-hydrodynamic (MHD) liquid film flow of a fourth order fluid past a vertical and vibratory plate. In this article have been developed for higher order complex nature fluids. The governing-equations have been modeled in the terms of nonlinear partial differential equations with the help of physical boundary circumstances. Two different analytical approaches i.e. Adomian decomposition method (ADM) and the optimal homotopy asymptotic method (OHAM), have been used for discoveryof the series clarification of the problems. Solutions obtained via two diversemethods have been compared using the graphs, tables and found an excellent contract. Variants of the embedded flow parameters in the solution have been analysed through the graphical diagrams.

  18. Current-induced domain wall motion in Co/Ni nano-wires with different Co and Ni thicknesses

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, K; Chiba, D; Koyama, T; Yamada, G; Ono, T [Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 (Japan); Tanigawa, H; Fukami, S; Suzuki, T; Ohshima, N; Ishiwata, N [NEC Corporation, 1120 Shimokuzawa, Chuo-ku, Sagamihara, Kanagawa 252-5298 (Japan); Nakatani, Y, E-mail: ono@scl.kyoto-u.ac.jp [University of Electro-communications, Chofu, Tokyo, 182-8585 (Japan)

    2011-01-01

    The authors have investigated magnetic domain wall motion induced by electric currents in ferromagnetic nano-wires made of Co/Ni multilayers. The thicknesses of Co and Ni layers were changed, whereas the numbers of layer stacks of Co and Ni were the same in all samples. The sample with thinner total Co/Ni thickness showed the lower threshold current density for the domain wall motion as an overall trend, which is qualitatively in agreement with the expectation by the theory based on the adiabatic spin-transfer model. The lowest threshold current density was 2.9x10{sup 11} A/m{sup 2} obtained in the sample with the total Co/Ni thickness of 3.4 nm and the wire width of 110 nm.

  19. Enhancement of spin Hall effect induced torques for current-driven magnetic domain wall motion: Inner interface effect

    KAUST Repository

    Bang, Do

    2016-05-23

    We investigate the current-induced domain wall motion in perpendicular magnetized Tb/Co wires with structure inversion asymmetry and different layered structures. We find that the critical current density to drive domain wall motion strongly depends on the layered structure. The lowest critical current density ∼15MA/cm2 and the highest slope of domain wall velocity curve are obtained for the wire having thin Co sublayers and more inner Tb/Co interfaces, while the largest critical current density ∼26MA/cm2 required to drive domain walls is observed in the Tb-Co alloy magnetic wire. It is found that the Co/Tb interface contributes negligibly to Dzyaloshinskii-Moriya interaction, while the effective spin-orbit torque strongly depends on the number of Tb/Co inner interfaces (n). An enhancement of the antidamping torques by extrinsic spin Hall effect due to Tb rare-earth impurity-induced skew scattering is suggested to explain the high efficiency of current-induced domain wall motion.

  20. A Study on Maneuvering Obstacle Motion State Estimation for Intelligent Vehicle Using Adaptive Kalman Filter Based on Current Statistical Model

    Directory of Open Access Journals (Sweden)

    Bao Han

    2015-01-01

    Full Text Available The obstacle motion state estimation is an essential task in intelligent vehicle. The ASCL group has developed such a system that uses a radar and GPS/INS. When running on the road, the acceleration of the vehicle is always changing, so it is hard for constant velocity (CV model and constant acceleration (CA model to describe the motion state of the vehicle. This paper introduced Current Statistical (CS model from military field, which uses the modified Rayleigh distribution to describe acceleration. The adaptive Kalman filter based on CS model was used to estimate the motion state of the target. We conducted simulation experiments and real vehicle tests, and the results showed that the estimation of position, velocity, and acceleration can be precise.

  1. Sit-stand and stand-sit transitions in older adults and patients with Parkinson's disease: event detection based on motion sensors versus force plates.

    Science.gov (United States)

    Zijlstra, Agnes; Mancini, Martina; Lindemann, Ulrich; Chiari, Lorenzo; Zijlstra, Wiebren

    2012-10-07

    Motion sensors offer the possibility to obtain spatiotemporal measures of mobility-related activities such as sit-stand and stand-sit transitions. However, the application of new sensor-based methods for assessing sit-stand-sit performance requires the detection of crucial events such as seat on/off in the sensor-based data. Therefore, the aim of this study was to evaluate the agreement of detecting sit-stand and stand-sit events based on a novel body-fixed-sensor method with a force-plate based analysis. Twelve older adults and 10 patients with mild to moderate Parkinson's disease with mean age of 70 years performed sit-stand-sit movements while trunk movements were measured with a sensor-unit at vertebrae L2-L4 and reaction forces were measured with separate force plates below the feet and chair. Movement onsets and ends were determined. In addition, seat off and seat on were determined based on forces acting on the chair. Data analysis focused on the agreement of the timing of sit-stand and stand-sit events as detected by the two methods. For the start and end of standing-up, only small delays existed for the start of forward trunk rotation and end of backward trunk rotation compared to movement onset/end as detected in the force-plate data. The end of forward trunk rotation had a small and consistent delay compared to seat off, whereas during sitting-down, the end of forward trunk rotation occurred earlier in relation to seat on. In detecting the end of sitting-down, backward trunk rotation ended after reaching the minimum in the below-feet vertical force signal. Since only small time differences existed between the two methods for detecting the start of sitting-down, longer movement durations were found for the sensor-based method. Relative agreement between the two methods in assessing movement duration was high (i.e. ICCs ≥ 0.75), except for duration of standing-up in the Parkinson's patients (ICC = 0.61). This study demonstrated high agreement of

  2. Sit-stand and stand-sit transitions in older adults and patients with Parkinson’s disease: event detection based on motion sensors versus force plates

    Science.gov (United States)

    2012-01-01

    Background Motion sensors offer the possibility to obtain spatiotemporal measures of mobility-related activities such as sit-stand and stand-sit transitions. However, the application of new sensor-based methods for assessing sit-stand-sit performance requires the detection of crucial events such as seat on/off in the sensor-based data. Therefore, the aim of this study was to evaluate the agreement of detecting sit-stand and stand-sit events based on a novel body-fixed-sensor method with a force-plate based analysis. Methods Twelve older adults and 10 patients with mild to moderate Parkinson’s disease with mean age of 70 years performed sit-stand-sit movements while trunk movements were measured with a sensor-unit at vertebrae L2-L4 and reaction forces were measured with separate force plates below the feet and chair. Movement onsets and ends were determined. In addition, seat off and seat on were determined based on forces acting on the chair. Data analysis focused on the agreement of the timing of sit-stand and stand-sit events as detected by the two methods. Results For the start and end of standing-up, only small delays existed for the start of forward trunk rotation and end of backward trunk rotation compared to movement onset/end as detected in the force-plate data. The end of forward trunk rotation had a small and consistent delay compared to seat off, whereas during sitting-down, the end of forward trunk rotation occurred earlier in relation to seat on. In detecting the end of sitting-down, backward trunk rotation ended after reaching the minimum in the below-feet vertical force signal. Since only small time differences existed between the two methods for detecting the start of sitting-down, longer movement durations were found for the sensor-based method. Relative agreement between the two methods in assessing movement duration was high (i.e. ICCs ≥ 0.75), except for duration of standing-up in the Parkinson’s patients (ICC = 0.61). Conclusions

  3. Ion motion in the current sheet with sheared magnetic field – Part 1: Quasi-adiabatic theory

    Directory of Open Access Journals (Sweden)

    A. V. Artemyev

    2013-02-01

    Full Text Available We present a theory of trapped ion motion in the magnetotail current sheet with a constant dawn–dusk component of the magnetic field. Particle trajectories are described analytically using the quasi-adiabatic invariant corresponding to averaging of fast oscillations around the tangential component of the magnetic field. We consider particle dynamics in the quasi-adiabatic approximation and demonstrate that the principal role is played by large (so called geometrical jumps of the quasi-adiabatic invariant. These jumps appear due to the current sheet asymmetry related to the presence of the dawn–dusk magnetic field. The analytical description is compared with results of numerical integration. We show that there are four possible regimes of particle motion. Each regime is characterized by certain ranges of values of the dawn–dusk magnetic field and particle energy. We find the critical value of the dawn–dusk magnetic field, where jumps of the quasi-adiabatic invariant vanish.

  4. Numerical Investigation of Flow Motion and Performance of A Horizontal Axis Tidal Turbine Subjected to A Steady Current

    Institute of Scientific and Technical Information of China (English)

    李林娟; 郑金海; 彭于轩; 张继生; 吴修广

    2015-01-01

    Horizontal axis tidal turbines have attracted more and more attentions nowadays, because of their convenience and low expense in construction and high efficiency in extracting tidal energy. The present study numerically investigates the flow motion and performance of a horizontal axis tidal turbine with a supporting vertical cylinder under steady current. In the numerical model, the continuous equation and incompressible Reynolds-averaged Navier-Stokes equations are solved, and the volume of fluid method is employed to track free surface motion. The RNG k-εmodel is adopted to calculate turbulence transport while the fractional area/volume obstacle representation method is used to describe turbine characteristics and movement. The effects of installation elevation of tidal turbine and inlet velocity on the water elevation, and current velocity, rotating speed and resultant force on turbine are discussed. Based on the comparison of the numerical results, a better understanding of flow structure around horizontal axis tidal turbine and turbine performance is achieved.

  5. Natural Convection Heat and Mass Transfer Flow with Hall Current, Rotation, Radiation and Heat Absorption Past an Accelerated Moving Vertical Plate with Ramped Temperature

    Directory of Open Access Journals (Sweden)

    Gauri Shanker Seth

    2015-01-01

    Full Text Available An investigation of unsteady hydromagnetic natural convection heat and mass trans fer flow with Hall current of a viscous, incompressible, electrically conducting, heat absorbing and optically thin radiating fluid past an accelerated moving vertical plate through fluid saturated porous medium in a rotating environment is carried out when temperature of the plate has a temporarily ramped profile. The exact solutions of momentum, energy and concentration equations are obtained in closed form by Laplace transform technique. The expressions of skin friction, Nusselt number and Sherwood number are also derived. For both ramped temperature and isothermal plates, Hall current tends to accelerate primary and secondary fluid velocities whereas heat absorption and radiation have reverse effect on it. Rotation tends to retard primary fluid velocity whereas it has a reverse effect on secondary fluid velocity. Heat absorption and radiation have tendency to enhance rate of heat transfer at the plate.

  6. Nitrite/nitrate detection in serum based on dual-plate generator-collector currents in a microtrench.

    Science.gov (United States)

    Gross, Andrew J; Holmes, Stephanie; Dale, Sara E C; Smallwood, Miranda J; Green, Stephen J; Winlove, C Peter; Benjamin, Nigel; Winyard, Paul G; Marken, Frank

    2015-01-01

    A dual-electrode sensor is developed for rapid detection of nitrite/nitrate at micromolar levels in phosphate buffer media and in dilute horse serum without additional sample pre-treatment. A generator-collector configuration is employed so that on one electrode nitrate is reduced to nitrite and on the second electrode nitrite is oxidised back to nitrate. The resulting redox cycle gives rise to a specific and enhanced current signal which is exploited for sensitive and reliable measurement of nitrite/nitrate in the presence of oxygen. The electrode design is based on a dual-plate microtrench (approximately 15 µm inter-electrode gap) fabricated from gold-coated glass and with a nano-silver catalyst for the reduction of nitrate. Fine tuning of the phosphate buffer pH is crucial for maximising collector current signals whilst minimising unwanted gold surface oxidation. A limit of detection of 24 μM nitrate and a linear concentration range of 200-1400 μM is reported for the microtrench sensor in phosphate buffer and dilute horse serum. Relative standard deviations for repeat measurements were in the range 1.8-6.9% (n=3) indicating good repeatability in both aqueous and biological media. Preliminary method validation against the standard chemiluminescence method used in medical laboratories is reported for nitrate analysis in serum.

  7. Mooring Tension and Motion Characteristics of A Submerged Fish Reef with Net in Waves and Currents Using Numerical Analysis

    Institute of Scientific and Technical Information of China (English)

    Tae Ho Kim; David W. Fredriksson; Judson DeCew

    2012-01-01

    A numerical model was used to analyze the motion response and mooring tension of a submerged fish reef system.The system included a net attached to a rigid structure suspended up from the bottom with a single,high tension mooring by fixed flotation.The analysis was performed by using a Morison equation type finite element model configured with truss elements.Input forcing parameters into the model consisted of both regular and irregular waves,with and without a steady current.Heave,surge and pitch dynamic calculations of the reef structure were made.Tension response results of the attached mooring line were also computed.Results were analyzed in both the time and frequency domain in which appropriate,linear transfer functions were calculated.The influence of the current was more evident in the tension and heave motion response data.This is most likely the result of the large buoyancy characteristics of the reef structure and the length of the mooring cable.Maximum mooring component tension was found to be 13.9 kN and occurred when the reef was subjected to irregular waves with a co-linear current of 1.0 m/s velocity.The results also showed that the system had little damping (in heave) with damped natural periods of 2.8 s.This combination of system characteristics promotes a possible resonating situation in typical open sea conditions with similar wave periods.

  8. 4层横向运动板防护长细杆的数值分析%Numerical Analysis of Four-Layer Plates with Transverse Motion Defending a Slender Rod

    Institute of Scientific and Technical Information of China (English)

    史忠鹏; 李治源; 孙立志

    2011-01-01

    多层横向运动板对垂直来侵长细杆的挤压、剪切能够使长细杆发生挤压和剪切变形,进而降低长细杆后续的侵彻能力,增强装甲的防护效果.利用LS-DYNA软件对多层横向、邻层反向运动的钢装甲板防护钨合金长细杆进行运动板速度和运动板的厚度分配的相关仿真计算.通过对计算结果中开坑形状、后效板侵深和装甲效能进行分析发现,随着板运动速度的增加,后效板开坑深度减小和开坑形状的非对称性加剧,运动板的干扰作用增强及防护效能提高;在运动板总厚度相同的情况下,板的层数越少,防护性能越好.%The shearing and squeezing impact on the slender rod caused by multi-layer plates with transverse motion results in the deformation of slender rod which normally penetrates into plates,decreasing the subsequent penetrating ability of the slender rod, then increasing the defending effect of armor. In the process that multi-layer steel armor plates with reverse transverse motion defend the tungsten alloy slender rod,the speed and thickness allocation of plates is simulated by LS-DYNA code. By analyzing the shape of crater and the penetrating depth in target plate and the effectiveness of armor,conclusion is obtained that as the speed of plates increases, the crater of target plate appears more asymmetric and is of smaller depth,the disturbing effect and the defending efficiency of plates are greatly increased; as the layers decrease,the defending efficiency of plates becomes better when the total thickness of plates is the same.

  9. 25/17MN双动厚板冲压液压机的电气控制系统%Electric control system of 25/17MN double motion hydraulic press punching thick plate

    Institute of Scientific and Technical Information of China (English)

    谭利红

    2001-01-01

    Electric control system of 25/17MN double motion hydraulic press punching thick plate and parameters operation manner have been introduced with analysis of graphic interface reality.%介绍了25/17MN双动厚板冲压液压机的电气控制系统及其系统中的参数处理方式,并对图形界面的实时性进行了分析。

  10. Roles of the magnetic field and electric current in thermally activated domain wall motion in a submicrometer magnetic strip with perpendicular magnetic anisotropy.

    Science.gov (United States)

    Emori, Satoru; Beach, Geoffrey S D

    2012-01-18

    We have experimentally studied micrometer-scale domain wall (DW) motion driven by a magnetic field and an electric current in a Co/Pt multilayer strip with perpendicular magnetic anisotropy. The thermal activation energy for DW motion, along with its scaling with the driving field and current, has been extracted directly from the temperature dependence of the DW velocity. The injection of DC current resulted in an enhancement of the DW velocity independent of the current polarity, but produced no measurable change in the activation energy barrier. Through this analysis, the observed current-induced DW velocity enhancement can be entirely and unambiguously attributed to Joule heating.

  11. Fault Segmentation and Earthquake Generation in the Transition from Strike-slip to Subduction Plate Motion, Saint Elias Orogen, Alaska and Yukon (Invited)

    Science.gov (United States)

    Bruhn, R. L.; Shennan, I.; Pavlis, T. L.

    2010-12-01

    The structural transition from strike-slip motion along the Fairweather transform fault to subduction on the Aleutian megathrust occurs within the collision zone between the Yakutat microplate and southern Alaska. The collision is marked by belts of thrust and strike-slip faulting both within the microplate and along its margins, forming a complex fault network that mechanically interacts with rupturing of the Aleutian megathrust on one hand, and the Fairweather transform fault on the other. For example, stress released by M8+ earthquakes within the central and eastern parts of the Yakutat microplate in 1899 may have constrained the 1964 rupture on the Aleutian megathrust to the western part of the microplate. However, megathrust earthquakes circa 900 BP and 1500 BP may have ruptured farther east than in 1964, generating earthquakes of significantly greater magnitude and tsunami potential. Structurally, the thrust-faulting earthquake of Sept. 10, 1899 occurred on faults that are loaded primarily by the Fairweather transform, but the earlier event of Sept. 4 is more closely linked to the Aleutian megathrust. Large reverse faults that rise off of the megathrust are superimposed on older structures within the microplate; creating complex duplex and wedge fault geometries beneath the mountains onshore that link to simpler fault propagation folds offshore. These lateral variations in fault network style correlate with 1) permanent uplift of the coast at ≈ 1 cm/yr in the Yakataga region of the microplate, 2) an abrupt change in structural style and orientation across the Kayak Island - Bering Glacier deformation zone, and 3) the seaward limit of ruptures in the 1899 earthquakes which occurred beneath the mountains onshore. Future goals include refining locations of earthquake source faults and determining the recurrence history of earthquakes within the Yakutat microplate. The history of rupturing within the microplate offshore is of particular interest given the

  12. EFFECT OF SLIP CONDITIONS AND HALL CURRENT ON UNSTEADY MHD FLOW OF A VISCOELASTIC FLUID PAST AN INFINITE VERTICAL POROUS PLATE THROUGH POROUS MEDIUM

    Directory of Open Access Journals (Sweden)

    RAKESH KUMAR,

    2011-04-01

    Full Text Available The purpose of this paper is to present a theoretical analysis of an unsteady hydromagnetic free convection flow of viscoelastic fluid (Walter’s B’ past an infinite vertical porous flat plate through porous medium. The temperature is assumed to be oscillating with time and the effect of the Hall current is taken into account. Assuming constant suction at the plate, closed form solutions have been obtained for velocity and temperature profiles. The effect of the various parameters, entering into the problem, on the primary, secondary velocity profiles, the axial and transverse components of skin-friction are shown graphically followed by quantitative discussion.

  13. GENERATING OF OPTIMAL QUANTIZATION LEVELS OF CONTROL CURRENTS FOR LINEAR STEPPING DRIVES OF PRECISION MOTION SYSTEMS

    Directory of Open Access Journals (Sweden)

    I. V. Dainiak

    2014-01-01

    Full Text Available The paper proposes a method of taking into account accumulated and temperature errors while forming coordinate discrete grid of a linear stepping drive. An algorithm for determination of optimal quantization levels of control currents of drive's phases has been developed in the paper; it minimizes an error of positioning that forms correction files for application of a control system in the software. Investigations on stability of discrete grid nodes coordinates have been carried our with the help of a monitoring station for accurate parameters of linear stepping drive. The investigations have proved an efficiency of the proposed algorithm and methodology for forming coordinate discrete grid.

  14. RANDOM VIBRATION OF A CURRENT CARRYING CIRCULAR PLATE IN MAGNETIC FIELD%载流圆板的磁弹性随机振动

    Institute of Scientific and Technical Information of China (English)

    王平; 李晓靓; 白象忠

    2012-01-01

    The magnetic-elastic random vibration problem of a current-carrying circular plate in a magnetic field is studied. Based on the magneto-elastic theory and the random vibration theory of a continue system with distributed parameters, the magneto-elastic random vibration equation of a current carrying circular plate in a magnetic field was derived. The stochastic response analysis of the circular plate in a magnetic field was finished. The auto-correlation function, power spectral density function and the mean function of the random displacement response of the circular plate in a magnetic field were obtained. In a specific example, the power spectral density function of the displacement response of the circular plate with stationary random current was calculated.%分析载流圆板在磁场中的磁弹性随机振动问题.根据薄板、薄壳体的磁弹性运动方程和连续体的随机振动理论,导出在磁场环境中圆板的磁弹性随机振动方程.对磁场中的载流圆板进行随机响应分析,得到圆板位移响应的自相关函数、功率谱密度函数及均值函数等数字特征.通过具体算例,对处于外加磁场中通入平稳随机电流的导电圆板,计算其位移响应的功率谱密度函数.

  15. Interaction of Streamwise and Wall-Normal Velocities in Combined Wave-Current Motion

    Institute of Scientific and Technical Information of China (English)

    Shu-Qing YANG; In-Soo KIM; Daniel S. KOH; Young-Chae SONG

    2005-01-01

    The aim of this paper is to present an analytical expression for the streamwise velocity distribution in a non-uniform flow in the presence of waves; the correlation between the horizontal and vertical velocity components has been comprehensively examined. Different from previous researches which attributed the deviation of velocity from the classical log-law to the wave Reynolds stress, i.e. -ρ(uv)only, this study demonstrates that the momentum flux caused by mean velocities, i.e.,(u)and(v) , is also responsible for the velocity deviation, and it is found that the streamwise velocity for a flow in the presence of non-zero wall-normal velocity does not follow the classical log-law, but the modified log-law proposed in this study based on simplified mixing-length theorem. The validity of the modified log-law has been verified by use of available experimental data from published sources for combined wave-current flows, and good agreement between the predicted and observed velocity profiles has been achieved.

  16. Plate Tearing by a Cone

    DEFF Research Database (Denmark)

    Simonsen, Bo Cerup

    1997-01-01

    The present paper is concerned with steady-state plate tearing by a cone. This is a scenario where a cone is forced through a ductile metal plate with a constant lateral tip penetration in a motion in the plane of the plate. The considered process could be an idealisaton of the damage, which...

  17. Plate Tearing by a Cone

    DEFF Research Database (Denmark)

    Simonsen, Bo Cerup

    1998-01-01

    The present paper is concerned with steady-state plate tearing by a cone. This is a scenario where a cone is forced through a ductile metal plate with a constant lateral tip penetration in a motion in the plane of the plate. The considered process could be an idealisation of the damage, which...

  18. Separating spin torque and heating effects in current-induced domain wall motion probed by high-resolution transmission electron microscopy

    DEFF Research Database (Denmark)

    Junginger, F.; Klaeui, M.; Backes, D.

    2007-01-01

    Observations of domain wall motion and transformations due to injected current pulses in permalloy zigzag structures using off-axis electron holography and Lorentz microscopy are reported. Heating on membranes leads to thermally activated random behavior at low current densities and by backcoating...

  19. Highly reduced current collapse in AlGaN/GaN high-electron-mobility transistors by combined application of oxygen plasma treatment and field plate structures

    Science.gov (United States)

    Asubar, Joel T.; Yoshida, Satoshi; Tokuda, Hirokuni; Kuzuhara, Masaaki

    2016-04-01

    We report on the highly reduced current collapse in AlGaN/GaN high-electron-mobility transistors (HEMTs) by combined application of pre-passivation oxygen (O2) plasma treatment and gate field plate (FP) structures schemes. Four different devices were fabricated in this work: (1) conventional HEMT as reference device, (2) field-plated HEMT, (3) O2 plasma-treated HEMT, (4) both field-plated and O2 plasma-treated HEMT. Analysis of dependence of normalized dynamic R on (NDR) on gate pulse on-time (t on) revealed that gate-FP reduces the emission time constant (τ i ) of trapped electrons while O2-plasma treatment decreases the density of traps. For all measurement conditions, the device with both FP and O2 plasma treatment exhibited the least NDR compared to devices with either FP or O2 plasma treatment only, demonstrating for the first time the compatibility of both O2 plasma treatment and FP schemes in mitigating current collapse.

  20. Geotectonic Elements, Stuctural Constraints and Current Problems for a Kinematic Reconstruction of the Caribbean Plate Margins during the Cretaceous.

    Science.gov (United States)

    Giunta, G.

    2001-12-01

    In the Caribbean Plate deformed margins are found relics of the Mid to Late Cretaceous eo-Caribbean tectonic phases, indicating the occurrence of sub-continental subduction zones with melange formation, and HP/LT metamorphism of ophiolitic rocks, and two main stages of intraoceanic subductions involving the unthickened proto-Caribbean oceanic lithosphere and/or supra-subduction complexes. These two stages are marked by the occurrence of (a) HP/LT metamorphic ophiolites and volcano-plutonic sequences with island-arc tholeiitic (IAT) or calc-alkaline (CA) affinities; (b) unmetamorphosed tonalitic intrusions of CA affinity below the proto-Caribbean thickened oceanic plateau. Since the Late Cretaceous the kinematics of the Caribbean Plate is closely related to the eastward drifting of the proto-Caribbean oceanic plateau (Colombia and Venezuela Basins) that produced both a diachronous tonalitic magmatism from 85-82 Ma, associated with a westward dipping oblique subduction of the proto-Caribbean-Atlantic ocean floor below the plateau, and an opposite dismembering of subduction complexes, of different ages along an E-W trend (North and South Caribbean Margins). This seems to be the consequence of the eastward shifting of both the northern and southern triple junctions, while allowing further bending of the Aves- Lesser Antilles arc. Moreover, the Caribbean oceanic plateau was trapped by different rotation rates of the Chortis, Chorotega and Choco blocks, during the construction of the western plate margin (Central American Isthmus). The previous Mid-Late Cretaceous eo-Caribbean evolution, correspondent to the beginning of the compressional conditions in Central America area, is characterized by sub-continental and/or intraoceanic subduction systems with associated IAT and CA arc magmatism. This simplified kinematic approach falls short in explaining (1) the Early Cretaceous paleogeography and morphology of the margins of the North, South American continents and minor

  1. Plate tectonics of the Mediterranean region.

    Science.gov (United States)

    McKenzie, D P

    1970-04-18

    The seismicity and fault plane solutions in the Mediterranean area show that two small rapidly moving plates exist in the Eastern Mediterranean, and such plates may be a common feature of contracting ocean basins. The results show that the concepts of plate tectonics apply to instantaneous motions across continental plate boundaries.

  2. How mantle slabs drive plate tectonics.

    Science.gov (United States)

    Conrad, Clinton P; Lithgow-Bertelloni, Carolina

    2002-10-04

    The gravitational pull of subducted slabs is thought to drive the motions of Earth's tectonic plates, but the coupling between slabs and plates is not well established. If a slab is mechanically attached to a subducting plate, it can exert a direct pull on the plate. Alternatively, a detached slab may drive a plate by exciting flow in the mantle that exerts a shear traction on the base of the plate. From the geologic history of subduction, we estimated the relative importance of "pull" versus "suction" for the present-day plates. Observed plate motions are best predicted if slabs in the upper mantle are attached to plates and generate slab pull forces that account for about half of the total driving force on plates. Slabs in the lower mantle are supported by viscous mantle forces and drive plates through slab suction.

  3. Low resistivity Ga-doped ZnO thin films of less than 100 nm thickness prepared by ion plating with direct current arc discharge

    OpenAIRE

    2007-01-01

    Low resistivity Ga-doped ZnO films were prepared on a glass substrate by ion plating with direct current arc discharge. Thickness dependent changes in the electrical properties of the films are reported, focusing on the thin films of less than 100 nm thickness. Structural analyses showed that the thinnest film of 30 nm thickness consists of well-oriented columnar grains normal to the substrate, and the resistivity was as low as 4.4×10−4 Ω cm. The changes in lattice strain and c-axis fluctuati...

  4. Influence of current density on surface morphology and properties of pulse plated tin films from citrate electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Ashutosh; Bhattacharya, Sumit; Das, Siddhartha; Das, Karabi, E-mail: karabi@metal.iitkgp.ernet.in

    2014-01-30

    Bulk polycrystalline tin films have been processed by pulse electrodeposition technique from a simple solution containing triammonium citrate and stannous chloride. The cathodic investigations have been carried out by galvanostatic methods. As deposited samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). XRD analysis of the deposited films shows microcrystalline grains having β-Sn form. The surface morphology is very rough at lower current density, but becomes smooth at higher current density, and exhibits pyramid type morphology at all the current densities. The effect of current density on microhardness, melting behavior, and electrical resistivity are also reported here.

  5. Plate tectonics drive tropical reef biodiversity dynamics.

    Science.gov (United States)

    Leprieur, Fabien; Descombes, Patrice; Gaboriau, Théo; Cowman, Peter F; Parravicini, Valeriano; Kulbicki, Michel; Melián, Carlos J; de Santana, Charles N; Heine, Christian; Mouillot, David; Bellwood, David R; Pellissier, Loïc

    2016-05-06

    The Cretaceous breakup of Gondwana strongly modified the global distribution of shallow tropical seas reshaping the geographic configuration of marine basins. However, the links between tropical reef availability, plate tectonic processes and marine biodiversity distribution patterns are still unknown. Here, we show that a spatial diversification model constrained by absolute plate motions for the past 140 million years predicts the emergence and movement of diversity hotspots on tropical reefs. The spatial dynamics of tropical reefs explains marine fauna diversification in the Tethyan Ocean during the Cretaceous and early Cenozoic, and identifies an eastward movement of ancestral marine lineages towards the Indo-Australian Archipelago in the Miocene. A mechanistic model based only on habitat-driven diversification and dispersal yields realistic predictions of current biodiversity patterns for both corals and fishes. As in terrestrial systems, we demonstrate that plate tectonics played a major role in driving tropical marine shallow reef biodiversity dynamics.

  6. Plate tectonics drive tropical reef biodiversity dynamics

    Science.gov (United States)

    Leprieur, Fabien; Descombes, Patrice; Gaboriau, Théo; Cowman, Peter F.; Parravicini, Valeriano; Kulbicki, Michel; Melián, Carlos J.; de Santana, Charles N.; Heine, Christian; Mouillot, David; Bellwood, David R.; Pellissier, Loïc

    2016-01-01

    The Cretaceous breakup of Gondwana strongly modified the global distribution of shallow tropical seas reshaping the geographic configuration of marine basins. However, the links between tropical reef availability, plate tectonic processes and marine biodiversity distribution patterns are still unknown. Here, we show that a spatial diversification model constrained by absolute plate motions for the past 140 million years predicts the emergence and movement of diversity hotspots on tropical reefs. The spatial dynamics of tropical reefs explains marine fauna diversification in the Tethyan Ocean during the Cretaceous and early Cenozoic, and identifies an eastward movement of ancestral marine lineages towards the Indo-Australian Archipelago in the Miocene. A mechanistic model based only on habitat-driven diversification and dispersal yields realistic predictions of current biodiversity patterns for both corals and fishes. As in terrestrial systems, we demonstrate that plate tectonics played a major role in driving tropical marine shallow reef biodiversity dynamics. PMID:27151103

  7. Plate tectonics drive tropical reef biodiversity dynamics

    Science.gov (United States)

    Leprieur, Fabien; Descombes, Patrice; Gaboriau, Théo; Cowman, Peter F.; Parravicini, Valeriano; Kulbicki, Michel; Melián, Carlos J.; de Santana, Charles N.; Heine, Christian; Mouillot, David; Bellwood, David R.; Pellissier, Loïc

    2016-05-01

    The Cretaceous breakup of Gondwana strongly modified the global distribution of shallow tropical seas reshaping the geographic configuration of marine basins. However, the links between tropical reef availability, plate tectonic processes and marine biodiversity distribution patterns are still unknown. Here, we show that a spatial diversification model constrained by absolute plate motions for the past 140 million years predicts the emergence and movement of diversity hotspots on tropical reefs. The spatial dynamics of tropical reefs explains marine fauna diversification in the Tethyan Ocean during the Cretaceous and early Cenozoic, and identifies an eastward movement of ancestral marine lineages towards the Indo-Australian Archipelago in the Miocene. A mechanistic model based only on habitat-driven diversification and dispersal yields realistic predictions of current biodiversity patterns for both corals and fishes. As in terrestrial systems, we demonstrate that plate tectonics played a major role in driving tropical marine shallow reef biodiversity dynamics.

  8. Sit-stand and stand-sit transitions in older adults and patients with Parkinson's disease : event detection based on motion sensors versus force plates

    NARCIS (Netherlands)

    Zijlstra, Agnes; Mancini, Martina; Lindemann, Ulrich; Chiari, Lorenzo; Zijlstra, Wiebren

    2012-01-01

    Background: Motion sensors offer the possibility to obtain spatiotemporal measures of mobility-related activities such as sit-stand and stand-sit transitions. However, the application of new sensor-based methods for assessing sit-stand-sit performance requires the detection of crucial events such as

  9. Sit-stand and stand-sit transitions in older adults and patients with Parkinson's disease : event detection based on motion sensors versus force plates

    NARCIS (Netherlands)

    Zijlstra, Agnes; Mancini, Martina; Lindemann, Ulrich; Chiari, Lorenzo; Zijlstra, Wiebren

    2012-01-01

    Background: Motion sensors offer the possibility to obtain spatiotemporal measures of mobility-related activities such as sit-stand and stand-sit transitions. However, the application of new sensor-based methods for assessing sit-stand-sit performance requires the detection of crucial events such as

  10. Tectonics of the Easter plate

    Science.gov (United States)

    Engeln, J. F.; Stein, S.

    1984-01-01

    A new model for the Easter plate is presented in which rift propagation has resulted in the formation of a rigid plate between the propagating and dying ridges. The distribution of earthquakes, eleven new focal mechanisms, and existing bathymetric and magnetic data are used to describe the tectonics of this area. Both the Easter-Nazca and Easter-Pacific Euler poles are sufficiently close to the Easter plate to cause rapid changes in rates and directions of motion along the boundaries. The east and west boundaries are propagating and dying ridges; the southwest boundary is a slow-spreading ridge and the northern boundary is a complex zone of convergent and transform motion. The Easter plate may reflect the tectonics of rift propagation on a large scale, where rigid plate tectonics requires boundary reorientation. Simple schematic models to illustrate the general features and processes which occur at plates resulting from large-scale rift propagation are used.

  11. Tectonics of the Easter plate

    Science.gov (United States)

    Engeln, J. F.; Stein, S.

    1984-01-01

    A new model for the Easter plate is presented in which rift propagation has resulted in the formation of a rigid plate between the propagating and dying ridges. The distribution of earthquakes, eleven new focal mechanisms, and existing bathymetric and magnetic data are used to describe the tectonics of this area. Both the Easter-Nazca and Easter-Pacific Euler poles are sufficiently close to the Easter plate to cause rapid changes in rates and directions of motion along the boundaries. The east and west boundaries are propagating and dying ridges; the southwest boundary is a slow-spreading ridge and the northern boundary is a complex zone of convergent and transform motion. The Easter plate may reflect the tectonics of rift propagation on a large scale, where rigid plate tectonics requires boundary reorientation. Simple schematic models to illustrate the general features and processes which occur at plates resulting from large-scale rift propagation are used.

  12. Anatomic fit of six different radial head plates: comparison of precontoured low-profile radial head plates.

    Science.gov (United States)

    Burkhart, Klaus Josef; Nowak, Tobias E; Kim, Yoon-Joo; Rommens, Pol M; Müller, Lars P

    2011-04-01

    Bulky implants may lead to symptomatic soft tissue irritation after open reduction and internal fixation of radial head and neck fractures. The purpose of our study was to compare the anatomic fit of precontoured radial head plates. We stripped 22 embalmed human cadaveric radiuses of soft tissues. We investigated 6 radial head plates: (1) the Medartis radial head buttress plate (MBP), (2) the Medartis radial head rim plate (MRP), (3) the Synthes radial neck plate (SNP), (4) the Synthes radial head plate (SHP), (5) the Acumed radial head plate (AHP), and (6) the Wright radial head plate (WHP). Each plate was applied to each radial head at the place of best fit within the safe zone. We tested 4 parameters of anatomic fit: (1) plate-to-bone distance, (2) plate contact judged by 3 different observers, (3) pin-subchondral zone distance, and (4) plate-to-bone contact after adjustment of the plates. The MBP and MRP showed the lowest profile by objective measurements, the SNP and AHP had a moderate profile, and the SHP and WHP demonstrated the bulkiest profile. The subjective assessments also demonstrated the best fit for the MBP, a good fit for the SNP, a moderate fit for the MRP and AHP, and a poor fit for the SHP and WHP. The MBP, MRP, and AHP could always provide pin-subchondral zone contact, unlike the SHP, SNP, and WHP. After bending, significant improvement of plate-to-bone distance could only be seen for the MBP, MRP, and WHP. The ranking among plates remained the same except for the WHP, which showed a significantly lower plate-to-bone distance than the SHP. Currently available radial head implants are heterogeneous. The MBP and MRP showed the lowest profile and best anatomic fit. Owing to the complex radial head anatomy, to date there is no one radial head plate that perfectly fits all radial heads. Conformance of existing plates to the radial head and neck is not perfect. Careful plate selection and modification, when necessary, may minimize interference of this

  13. Application of GPS in Crustal Deformation and Plate Motion Monitoring%GPS在地壳形变和板块运动监测中的应用

    Institute of Scientific and Technical Information of China (English)

    钱进; 韩志云; 林学峰; 吴星

    2013-01-01

    简要介绍了GPS在现代板块构造运动中的应用及其进展:GPS对于地球参考框架的建立和维持发挥着重要的作用;大量地壳运动监测网的建立使得GPS成为监测地壳运动强有力的工具;全球性、全天候的GPS卫星测高将在现代板块构造运动的监测中发挥重要作用;高精度的IGS产品为国际动力学服务提供坚实的数据基础.%In this paper,a brief introduction of GPS in modem plate tectonics and its progress is presented-the role GPS plays in the establishment and maintenance of the Earth's frame of reference,establishment of large crustal movement monitoring network which makes GPS monitoring crustal movement the strong tool,the important role the global and all-weather GPS satellite altimetry plays in the modern plate tectonic movement monitoring,and the solid data base the highly precise IGS products provide for the international dynamics services.

  14. High-frequency techniques for RCS prediction of plate geometries and a physical optics/equivalent currents model for the RCS of trihedral corner reflectors

    Science.gov (United States)

    Balanis, Constantine A.; Polka, Lesley A.; Polycarpou, Anastasis C.

    1993-01-01

    Part 1 of this report continues the investigation, initiated in previous reports, of scattering from rectangular plates coated with lossy dielectrics. The hard polarization coefficients given in the last report are incorporated into a model, which includes second- and third-order diffractions, for the coated plate. Computed results from this model are examined and compared to measured data. A breakdown of the contribution of each of the higher-order terms to the total radar cross section (RCS) is given. The effectiveness of the uniform theory of diffraction (UTD) model in accounting for the coating effect is investigated by examining a Physical Optics (PO) model which incorporates the equivalent surface impedance approximation used in the UTD model. The PO, UTD, and experimental results are compared. Part 2 of this report presents a RCS model, based on PO and the Method of Equivalent Currents (MEC), for a trihedral corner reflector. PO is used to account for the reflected fields, while MEC is used for the diffracted fields. Single, double, and triple reflections and first-order diffractions are included in the model. A detailed derivation of the E(sub theta)-polarization, monostatic RCS is included. Computed results are compared with finite-difference time-domain (FDTD) results for validation. The PO/MEC model of this report compares very well with the FDTD model, and it is a much faster model in terms of computational speed.

  15. Current status of research and application of cyanide-free plating processes and related recommendations%无氰电镀工艺研究与应用现状及建议

    Institute of Scientific and Technical Information of China (English)

    徐金来; 赵国鹏; 胡耀红

    2012-01-01

    介绍了无氰浸锌,无氰镀铜,无氰镀锌,无氰镀铜锡合金,无氰镀黄铜或仿金,无氰镀银,无氰镀金等工艺的研究和应用现状,探讨了无氰电镀工艺的适用范围及特点,提出了改进的方向,为推进无氰电镀工艺的研究和应用,实现淘汰氰化物电镀工艺,促进电镀行业清洁生产实施提供参考.%The current research and application of cyanide-free processes for zinc immersion, copper plating, zinc plating, copper-tin alloy plating, brass or imitation gold plating, silver plating, and gold plating were introduced. Their characteristics and application scope were discussed. Some suggestions on development directions were given. This article serves as a reference for accelerating the research and application of cyanide-free plating processes, finding alternatives to cyanide plating, and promoting the implementation of cleaner production in electroplating industry.

  16. Plate tectonics conserves angular momentum

    Directory of Open Access Journals (Sweden)

    C. Bowin

    2009-03-01

    Full Text Available A new combined understanding of plate tectonics, Earth internal structure, and the role of impulse in deformation of the Earth's crust is presented. Plate accelerations and decelerations have been revealed by iterative filtering of the quaternion history for the Euler poles that define absolute plate motion history for the past 68 million years, and provide an unprecedented precision for plate angular rotation variations with time at 2-million year intervals. Stage poles represent the angular rotation of a plate's motion between adjacent Euler poles, and from which the maximum velocity vector for a plate can be determined. The consistent maximum velocity variations, in turn, yield consistent estimates of plate accelerations and decelerations. The fact that the Pacific plate was shown to accelerate and decelerate, implied that conservation of plate tectonic angular momentum must be globally conserved, and that is confirmed by the results shown here (total angular momentum ~1.4 E+27 kgm2s−1. Accordingly, if a plate decelerates, other plates must increase their angular momentums to compensate. In addition, the azimuth of the maximum velocity vectors yields clues as to why the "bend" in the Emperor-Hawaiian seamount trend occurred near 46 Myr. This report summarizes processing results for 12 of the 14 major tectonic plates of the Earth (except for the Juan de Fuca and Philippine plates. Plate accelerations support the contention that plate tectonics is a product of torques that most likely are sustained by the sinking of positive density anomalies due to phase changes in subducted gabbroic lithosphere at depth in the upper lower mantle (above 1200 km depth. The tectonic plates are pulled along by the sinking of these positive mass anomalies, rather than moving at near constant velocity on the crests of convection cells driven by rising heat. These results imply that spreading centers are primarily passive reactive

  17. Current Performance Characteristics of NASA Langley Research Center's Cockpit Motion Base and Standardized Test Procedure for Future Performance Characterization

    Science.gov (United States)

    Cowen, Brandon; Stringer, Mary T.; Hutchinson, Brian K.; Davidson, Paul C.; Gupton, Lawrence E.

    2014-01-01

    This report documents the updated performance characteristics of NASA Langley Research Center's (LaRC) Cockpit Motion Base (CMB) after recent revisions that were made to its inner-loop, feedback control law. The modifications to the control law will be briefly described. The performance of the Cockpit Motion Facility (CMF) will be presented. A short graphical comparison to the previous control law can be found in the appendix of this report. The revised controller will be shown to yield reduced parasitic accelerations with respect to the previous controller. Metrics based on the AGARD Advisory Report No. 144 are used to assess the overall system performance due to its recent control algorithm modification. This report also documents the standardized simulator test procedure which can be used in the future to evaluate potential updates to the control law.

  18. Relations between plate kinematics, slab geometry and overriding plate deformation in subduction zones: insights from statistical observations and laboratory modelling

    Science.gov (United States)

    Heuret, A.; Funiciello, F.; Faccenna, C.; Lallemand, S.

    2005-12-01

    3-D laboratory models have been performed in order to investigate the way plates kinematics (subducting and overriding plate absolute motions and the resulting plate convergence rate) influences the geometry of the slab and the overriding plate deformation in subduction zones. In the experiments a viscous plate of silicone (subducting plate) is pushed beneath another plate, which is itself pushed toward or pulled away from the trench (overriding plate), and sinks into a viscous layer of glucose syrup (upper mantle). The subducting and overriding plate velocities explored the variability field of natural subduction plates kinematics. The overriding plate motion exerts a primary role in the control of slab geometries and overriding plate deformation rates. The experiments have revealed two different subduction behaviours: (Style I) the overriding plate moves toward the trench and shortens at high rates, the slab is flat and deflected when reaching the bottom of the box in a forward direction; (Style II) the overriding plates moves away from the trench and shortens at low rates the slab is steep and deflected on the box bottom in a backward direction. To a lesser extent, increasing subducting plate motion is associated to increasing slab dips and overriding plate shortening. Slab geometry and overriding plate deformation are less sensitive to the overall plate convergence rate. These laboratory models behaviours are consistent with statistical analysis performed on natural subduction zones, and enlighten the first order control exerted by the overriding plate absolute motion, on the geometry adopted by the slab and the way the overriding plate deforms.

  19. Using the Mesozoic History of the Canadian Cordillera as a Case Study in Teaching Plate Tectonics.

    Science.gov (United States)

    Chamberlain, Valerie Elaine

    1989-01-01

    Reviews a model used in the teaching of plate tectonics which includes processes and concepts related to: terranes and the amalgamation of terranes, relative plate motion and oblique subduction, the effects of continent-continent collision, changes in plate motion, plate configuration, and the type of plate boundary. Diagrams are included.…

  20. Using the Mesozoic History of the Canadian Cordillera as a Case Study in Teaching Plate Tectonics.

    Science.gov (United States)

    Chamberlain, Valerie Elaine

    1989-01-01

    Reviews a model used in the teaching of plate tectonics which includes processes and concepts related to: terranes and the amalgamation of terranes, relative plate motion and oblique subduction, the effects of continent-continent collision, changes in plate motion, plate configuration, and the type of plate boundary. Diagrams are included.…

  1. Moving Divertor Plates in a Tokamak

    Energy Technology Data Exchange (ETDEWEB)

    S.J. Zweben, H. Zhang

    2009-02-12

    Moving divertor plates could help solve some of the problems of the tokamak divertor through mechanical ingenuity rather than plasma physics. These plates would be passively heated on each pass through the tokamak and cooled and reprocessed outside the tokamak. There are many design options using varying plate shapes, orientations, motions, coatings, and compositions.

  2. Stability analysis of the fluttering and autorotation of flow-induced rotation of a hinged flat plate

    Institute of Scientific and Technical Information of China (English)

    MIRZAEISEFAT Sina; FERNANDES Antonio Carlos

    2013-01-01

    This work describes investigations performed on the interaction of uniform current and freely rotating plate about a fixed vertical axis. Fluttering and autorotation are two different motions that may occur during the flow induced rotation. The dimensional analysis proves that the motion in flow induced rotation motion is governed essentially by the dimensionless moment of inertia and Reynolds number. Certain combinations define the stability boundaries between fluttering and autorotation. Fluttering is oscillation of body about a vertical axis and the autorotation is a name given to the case when the body turns continuously about the vertical axis. First, the loads and moment coefficients are calculated by experiments and streamline theory for different angles of attack for a fixed flat plate. Then for dynamic case, a bifurcation diagram is presented based on experiments to classify different motion states of flow induced rotation. Finally, a dynamical model is proposed for stability analysis of flow induced rotation of a flat plate.

  3. Anomalous low-frequency noise in synthetic antiferromagnets: possible evidence of current-induced domain-wall motion

    NARCIS (Netherlands)

    Herranz, D.; Guerrero, R.; Villar, R.; Aliev, F.G.; Swaving, A.C.; Duine, R.A.; Van Haesendonck, C.; Vavra, I.

    2009-01-01

    We investigate current-driven magnetization dynamics in synthetic [Fe/Cr]10 multilayer antiferromagnets by using low-frequency voltage noise measurements. We observe suppression of the noise above a critical current density of about 2×105 A/cm2. Theoretical estimates suggest that this effect may be

  4. Simulations and measurements of artificial cracks and pits in flat stainless steel plates using tone burst eddy-current thermography (TBET)

    Science.gov (United States)

    Libin, M. N.; Balasubramaniam, Krishnan; Maxfield, B. W.; Krishnamurthy, C. V.

    2013-01-01

    Tone Burst Eddy current Thermography (TBET) is a new hybrid, non-contacting, Non-Destructive Evaluation (NDE) method which employs a combination of Pulsed Eddy current Thermography (PEC) and Thermographic Non-Destructive Evaluation (TNDE). For understanding the influence of cracking and pitting on heat generation and flow within a metallic body, a fundamental knowledge of the detailed induced current density distribution in the component under test is required. This information enables us to calculate the amount of heat produced by the defects and how that heat diffuses to the surface where it is imaged. This paper describes simulation work done for artificial pits and cracks within pits on the far surface of poorly conducting metals like stainless steel. The first phase of this investigation simulates the transient thermal distribution for artificial 2D pit and crack-like defects using the finite element package COMSOL multi-physics with the AC/DC module and general heat transfer. Considering the reflection measurement geometry where thermal excitation and temperature monitoring are on the same surface, pitting reduces the material volume thereby contributing to a larger temperature rise for the same thermal energy input. A crack within a pit gives a further increase in temperature above the pure pit baseline. The tone burst frequency can be changed to obtain approximately uniform heating (low frequency) or heating of a thin region at the observation surface. Although front surface temperature changes due to 10% deep far-side pits in a 6 mm thick plate can be measured, it is not yet clear whether a 20% deep crack within this pit can be discriminated against the background. Both simulations and measurements will be presented. The objective of this work is to determine whether the TBET method is suitable for the detection and characterization of far side pitting, cracking and cracks within those pits.

  5. Current-driven domain wall motion due to volume spin transfer torque in Co/Ni multilayer systems on Au underlayer

    Science.gov (United States)

    Ryu, Kwang-Su; Yang, See-Hun; Thomas, Luc; Parkin, Stuart

    2016-09-01

    We have studied the current-induced domain wall (CIDW) dynamics in perpendicularly magnetized Co/Ni multilayers deposited on Au underlayer, where the conventional spin transfer torque governs the domain wall dynamics, by the Kerr microscope. It is found that the DW angle tilting following Oersted field profile plays an important role in domain wall (DW) motion at high current density J by decreasing DW velocity with the increasing J, while distorting its DW morphology. Also we find that the DW pinning becomes pronounced as the anisotropy decreases by increasing number of Co/Ni repeats. Most remarkably, the DW tilting angle changes its sign by inserting ultrathin Pt layer between Au and Co layer, which suggests that the Dzyaloshinskii-Moriya interaction and spin Hall effect induces opposite effect in DW tilting. Our findings can be of use for application of CIDW to spintronics with perpendicularly magnetized systems.

  6. A diagrammatic description of the equations of motion, current and noise within the second-order von Neumann approach

    DEFF Research Database (Denmark)

    Karlstrom, O.; Emary, C.; Zedler, P.

    2013-01-01

    comparison sheds light on the validity of all these self-consistent second-order approaches. We analyze the discrepancy between the noise calculated by our method and the exact Levitov formula for a simple non-interacting quantum dot model. Furthermore, we study the noise of the canyon of current suppression...

  7. Manipulation of multiple 360o domain wall structures and its current-driven motion in a magnetic nanostripe

    Directory of Open Access Journals (Sweden)

    Wenjun Dong

    2015-11-01

    Full Text Available Dynamics of multiple transverse walls (TWs in a magnetic nanostripe is studied by micromagnetic simulations. It shows that, when TWs are arranged in a stripe with same orientation, they will attract each other and finally annihilate. However, when adjacent TWs are arranged with opposite orientation, a metastable complex wall can be formed, e.g., two TWs lead to 360o wall. For three or more TWs, the formed complex wall includes a number of 360o substructures, which is called multiple 360o structure (M360S here. The M360S itself may be used to store multiple logical data since each 360o substructure can act as logical ”0” or ”1”. On the other hand, the M360S may behave like single TW under an applied current, namely, the M360S can be driven steadily by current like that of single TW. A parity effect of the number of 360o substructures on the critical current for the annihilation is found. Namely, when the number is odd or even, the critical current increase or decrease with the increasing of the number, respectively. The parity effect is relevant to the out-of-plane magnetic moment of the M360S.

  8. Beyond plate tectonics - Looking at plate deformation with space geodesy

    Science.gov (United States)

    Jordan, Thomas H.; Minster, J. Bernard

    1988-01-01

    The requirements that must be met by space-geodetic systems in order to constrain the horizontal secular motions associated with the geological deformation of the earth's surface are explored. It is suggested that in order to improve existing plate-motion models, the tangential components of relative velocities on interplate baselines must be resolved to an accuracy of less than 3 mm/yr. Results indicate that measuring the velocities between crustal blocks to + or - 5 mm/yr on 100-km to 1000-km scales can produce geologically significant constraints on the integrated deformation rates across continental plate-boundary zones such as the western United States.

  9. Beyond plate tectonics - Looking at plate deformation with space geodesy

    Science.gov (United States)

    Jordan, Thomas H.; Minster, J. Bernard

    1988-01-01

    The requirements that must be met by space-geodetic systems in order to constrain the horizontal secular motions associated with the geological deformation of the earth's surface are explored. It is suggested that in order to improve existing plate-motion models, the tangential components of relative velocities on interplate baselines must be resolved to an accuracy of less than 3 mm/yr. Results indicate that measuring the velocities between crustal blocks to + or - 5 mm/yr on 100-km to 1000-km scales can produce geologically significant constraints on the integrated deformation rates across continental plate-boundary zones such as the western United States.

  10. HALL CURRENT AND ION SLIP EFFECTS ON THREE DIMENSIONAL UNSTEADY MHD COUETTE FLOW BOUNDED BETWEEN TWO POROUS PLATES WITH SLIP BOUNDARY CONDITION

    Directory of Open Access Journals (Sweden)

    K. Sumathi

    2016-07-01

    Full Text Available This paper deals with the influence of Hall and ion slip effects on three dimensional unsteady MHD flow of a viscous ncompressible fluid between the vertical flat porous plates separated by a finite distance in a slip flow regime. The moving plate is subjected to a constant injection V0 and the stationary plate to a transverse sinusoidal suction velocity distribution, so that the flow becomes three dimensional. Approximate solutions for cross flow, main flow velocities, skin friction and rate of heat transfer were found using perturbation techniques. The effects of various parameters involved in the problem on flow characteristics were studied numerically.

  11. Real Plates and Dubious Microplates

    Science.gov (United States)

    Kogan, M. G.; Steblov, G. M.

    2008-12-01

    From the onset of plate tectonics, the existence of most of the plates was never put in doubt, although the boundaries of some plates, like Africa, were later revised. There are however, two microplates in northeast Asia, the Amurian and Okhotsk, whose existence and the sense of rotation was revised several times. The rms value of plate-residual GPS velocities is 0.5-0.9 mm/a for sets of stations representing the motion of the following plates: Antarctic, Australian, Eurasian, North American, Nubian, Pacific, and South American. This value can be regarded as an upper bound on deviation of real plates from infinite stiffness. The rms value of plate-residual GPS velocities is 1.2-1.8 mm/a for the Indian, Nazca, and Somalian plates. Higher rms values for India and Nazca are attributed to the noisier data. The higher rms value for Somalia appears to arise from the distributed deformation to the east of the East African Rift; whether this statement is true can only be decided from observations of denser network in the future. From the analysis of plate-residual GPS velocities, the Canadian Arctic and northeastern Siberia belong to the North American plate. The detailed GPS survey on Sakhalin Island shows that the Sea of Okhotsk region also belongs to the North American plate while the region to the west of it belongs to the Eurasian plate. These results provide a constraint on the geometry of the North American plate and put in doubt the existence of smaller plates in northeast Asia.

  12. Rapid change in drift of the Australian plate records collision with Ontong Java plateau.

    Science.gov (United States)

    Knesel, Kurt M; Cohen, Benjamin E; Vasconcelos, Paulo M; Thiede, David S

    2008-08-01

    The subduction of oceanic plateaux, which contain extraordinarily thick basaltic crust and are the marine counterparts of continental flood-basalt provinces, is an important factor in many current models of plate motion and provides a potential mechanism for triggering plate reorganization. To evaluate such models, it is essential to decipher the history of the collision between the largest and thickest of the world's oceanic plateaux, the Ontong Java plateau, and the Australian plate, but this has been hindered by poor constraints for the arrival of the plateau at the Melanesian trench. Here we present (40)Ar-(39)Ar geochronological data on hotspot volcanoes in eastern Australian that reveal a strong link between collision of the Greenland-sized Ontong Java plateau with the Melanesian arc and motion of the Australian plate. The new ages define a short-lived period of reduced northward plate motion between 26 and 23 Myr ago, coincident with an eastward offset in the contemporaneous tracks of seamount chains in the Tasman Sea east of Australia. These features record a brief westward deflection of the Australian plate as the plateau entered and choked the Melanesian trench 26 Myr ago. From 23 Myr ago, Australia returned to a rapid northerly trajectory at roughly the same time that southwest-directed subduction began along the Trobriand trough. The timing and brevity of this collisional event correlate well with offsets in hotspot seamount tracks on the Pacific plate, including the archetypal Hawaiian chain, and thus provide strong evidence that immense oceanic plateaux, like the Ontong Java, can contribute to initiating rapid change in plate boundaries and motions on a global scale.

  13. The moving plate capacitor paradox

    Science.gov (United States)

    Davis, B. R.; Abbott, D.; Parrondo, J. M. R.

    2000-03-01

    For the first time we describe an apparent paradox concerning a moving plate capacitor driven by thermal noise from a resistor. A demon restores the plates of the capacitor to their original position, only when the voltage across the capacitor is small—hence only small forces are present for the demon to work against. The demon has to work harder than this to avoid the situation of perpetual motion, but the question is how? We explore the concept of a moving plate capacitor, driven by noise, a step further by examining the case where the restoring force on the capacitor plates is provided by a simple spring, rather than some unknown demon. We display simulation results with interesting behavior, particularly where the capacitor plates collide with each other.

  14. Flow and plate motion in compressor valves

    NARCIS (Netherlands)

    Habing, Reinder André

    2005-01-01

    The Basic Valve Theory is based on steady ow characteristics. Therefore unsteady ow conditions in the model valve have been considered in order to assess effects of unsteadiness on the performance of the Basic Valve Theory. The instantaneous gas force was predicted rather accurately by the theory. H

  15. Experimental study of nonlinear interaction of plasma flow with charged thin current sheets: 1. Boundary structure and motion

    Directory of Open Access Journals (Sweden)

    E. Amata

    2006-01-01

    Full Text Available We study plasma transport at a thin magnetopause (MP, described hereafter as a thin current sheet (TCS, observed by Cluster at the southern cusp on 13 February 2001 around 20:01 UT. The Cluster observations generally agree with the predictions of the Gas Dynamic Convection Field (GDCF model in the magnetosheath (MSH up to the MSH boundary layer, where significant differences are seen. We find for the MP a normal roughly along the GSE x-axis, which implies a clear departure from the local average MP normal, a ~90 km thickness and an outward speed of 35 km/s. Two populations are identified in the MSH boundary layer: the first one roughly perpendicular to the MSH magnetic field, which we interpret as the "incident" MSH plasma, the second one mostly parallel to B. Just after the MP crossing a velocity jet is observed with a peak speed of 240 km/s, perpendicular to B, with MA=3 and β>10 (peak value 23. The magnetic field clock angle rotates by 70° across the MP. Ex is the main electric field component on both sides of the MP, displaying a bipolar signature, positive on the MSH side and negative on the opposite side, corresponding to a ~300 V electric potential jump across the TCS. The E×B velocity generally coincides with the perpendicular velocity measured by CIS; however, in the speed jet a difference between the two is observed, which suggests the need for an extra flow source. We propose that the MP TCS can act locally as an obstacle for low-energy ions (<350 eV, being transparent for ions with larger gyroradius. As a result, the penetration of plasma by finite gyroradius is considered as a possible source for the jet. The role of reconnection is briefly discussed. The electrodynamics of the TCS along with mass and momentum transfer across it are further discussed in the companion paper by Savin et al. (2006.

  16. Determination of Euler parameters of Philippine Sea plate and the inferences

    Institute of Scientific and Technical Information of China (English)

    臧绍先; 陈起永; 宁杰远; 沈正康; 刘永刚

    2002-01-01

    Euler vectors of 12 plates, including Philippine Sea plate (PH), relative to a randomly fixed Pacific plate(PA) were determined by inverting the 1122 data from NUVEL-1 global plate motion model, earthquake slip vectors along Philippine Sea plate boundary, and GPS observed velocities. Euler vectors of Philippine Sea plate relative to adjacent plates are also gained. Our results are well consistent with observed data and can satisfy the geological and geophysical constraints along the Caroline(CR)-PH and PA-CR boundaries. Deformation of Philippine Sea plate is also discussed by using the plate motion Euler parameters.

  17. Saturn's Periodic Magnetosphere: The Relation Between Periodic Hot Plasma Injections, a Rotating Partial Ring Current, Global Magnetic Field Distortions, Plasmapause Motion, and Radio Emissions

    Science.gov (United States)

    Brandt, P. C.; Mitchell, D. G.; Gurnett, D. A.; Persoon, A. M.; Tsyganenko, N. A.

    2012-04-01

    It has been know for some time that the large-scale energetic particle injections (~3-200 keV) on the nigh side of Saturn observed by Cassini/INCA are closely tracked by the periodic Saturn Kilometric Radiation (SKR). The resulting energetic particle pressure is comparable to that of the colder plasma and it therefore distorts the global magnetic field significantly as the energetic particle population drifts around Saturn. In this presentation we discuss the important consequences this has for the large-scale dynamics and configuration of the entire inner magnetosphere of Saturn. We begin by reviewing the observational correlations between remote, global INCA observations of energetic particles, magnetic field distortions, and radio emissions. We present examples of how the magnetic field measurements and the INCA observations show direct implications of a rotating 3D electrical current system associated with, not only, the energetic particle pressure, but also with an interhemispheric field-aligned current (FAC) system. Recently, we found an intriguing high correlation also between the periodic motion of the high-latitude plasmapause-like boundary reported by Gurnett et al. [2011] and the energetic particles observed remotely by INCA that are periodically injected on the night side and then drift around Saturn according to their energy. In our preliminary analysis we see a direct correlation in at least 75% of the case with the center of drifting energetic particle distribution [Brandt et al., 2010] and the encounter with the rotating plasmapause-like density boundary [Gurnett et al., 2011]. However, the remaining, low-correlation cases suggest that we do not fully understand the global, 3D current system that produces the periodic perturbations in Saturn's magnetosphere. We will use these observations to constrain the underlying 3D current system and in particular, assess the role of interhemispheric FACs in reproducing the observations.

  18. Earth's Decelerating Tectonic Plates

    Energy Technology Data Exchange (ETDEWEB)

    Forte, A M; Moucha, R; Rowley, D B; Quere, S; Mitrovica, J X; Simmons, N A; Grand, S P

    2008-08-22

    Space geodetic and oceanic magnetic anomaly constraints on tectonic plate motions are employed to determine a new global map of present-day rates of change of plate velocities. This map shows that Earth's largest plate, the Pacific, is presently decelerating along with several other plates in the Pacific and Indo-Atlantic hemispheres. These plate decelerations contribute to an overall, globally averaged slowdown in tectonic plate speeds. The map of plate decelerations provides new and unique constraints on the dynamics of time-dependent convection in Earth's mantle. We employ a recently developed convection model constrained by seismic, geodynamic and mineral physics data to show that time-dependent changes in mantle buoyancy forces can explain the deceleration of the major plates in the Pacific and Indo-Atlantic hemispheres.

  19. Earth's Decelerating Tectonic Plates

    Energy Technology Data Exchange (ETDEWEB)

    Forte, A M; Moucha, R; Rowley, D B; Quere, S; Mitrovica, J X; Simmons, N A; Grand, S P

    2008-08-22

    Space geodetic and oceanic magnetic anomaly constraints on tectonic plate motions are employed to determine a new global map of present-day rates of change of plate velocities. This map shows that Earth's largest plate, the Pacific, is presently decelerating along with several other plates in the Pacific and Indo-Atlantic hemispheres. These plate decelerations contribute to an overall, globally averaged slowdown in tectonic plate speeds. The map of plate decelerations provides new and unique constraints on the dynamics of time-dependent convection in Earth's mantle. We employ a recently developed convection model constrained by seismic, geodynamic and mineral physics data to show that time-dependent changes in mantle buoyancy forces can explain the deceleration of the major plates in the Pacific and Indo-Atlantic hemispheres.

  20. Classifying Motion.

    Science.gov (United States)

    Duzen, Carl; And Others

    1992-01-01

    Presents a series of activities that utilizes a leveling device to classify constant and accelerated motion. Applies this classification system to uniform circular motion and motion produced by gravitational force. (MDH)

  1. Analysis and Calculation on the Slide Plate's Temperature of the Pantograph and Catenary System under Current-receiving Condition%弓网系统受流摩擦下滑板温度分析与计算

    Institute of Scientific and Technical Information of China (English)

    陈忠华; 康立乾; 李本君; 石英龙; 王铁军

    2012-01-01

    The temperature of the slide plate of the pantograph and catenary system is a key factor which affects the wear rate of the slide plate. This article has established the mathematical model of temperature field of the slide plate based on the heat transfer principle and finite element methods with boundary conditions. Through the finite element analysis software ANSYS modeling and calculating, the influence of normal load, velocity and current variation on the slide plate conductive spots' temperature have been obtained. The validity of the ANSYS modeling has been testified by comparing the simulation and experimental data.%弓网系统受流摩擦下滑板温度是影响其磨耗率的关键因素.笔者根据传热学原理和有限元方法,建立了滑板温度场的计算模型,给出了边界条件,并运用ANSYS建模和计算,得出载荷、速度、电流变化对滑板导电斑点温度的影响,并通过与实验数据对比证明了仿真模型的正确性.

  2. Plate tectonics, damage and inheritance.

    Science.gov (United States)

    Bercovici, David; Ricard, Yanick

    2014-04-24

    The initiation of plate tectonics on Earth is a critical event in our planet's history. The time lag between the first proto-subduction (about 4 billion years ago) and global tectonics (approximately 3 billion years ago) suggests that plates and plate boundaries became widespread over a period of 1 billion years. The reason for this time lag is unknown but fundamental to understanding the origin of plate tectonics. Here we suggest that when sufficient lithospheric damage (which promotes shear localization and long-lived weak zones) combines with transient mantle flow and migrating proto-subduction, it leads to the accumulation of weak plate boundaries and eventually to fully formed tectonic plates driven by subduction alone. We simulate this process using a grain evolution and damage mechanism with a composite rheology (which is compatible with field and laboratory observations of polycrystalline rocks), coupled to an idealized model of pressure-driven lithospheric flow in which a low-pressure zone is equivalent to the suction of convective downwellings. In the simplest case, for Earth-like conditions, a few successive rotations of the driving pressure field yield relic damaged weak zones that are inherited by the lithospheric flow to form a nearly perfect plate, with passive spreading and strike-slip margins that persist and localize further, even though flow is driven only by subduction. But for hotter surface conditions, such as those on Venus, accumulation and inheritance of damage is negligible; hence only subduction zones survive and plate tectonics does not spread, which corresponds to observations. After plates have developed, continued changes in driving forces, combined with inherited damage and weak zones, promote increased tectonic complexity, such as oblique subduction, strike-slip boundaries that are subparallel to plate motion, and spalling of minor plates.

  3. Weigh - in - motion (WIM)

    OpenAIRE

    Todorović Neven B.; Subotić Marko M.

    2014-01-01

    The biggest wealth of every country lies in its transportation infrastructure so the protection of negative impacts on infrastructure must be provided. The progress of sensor technology proposes today several types of weigh-in-motion systems, which have been tested for their efficiency, accuracy and cost-effectiveness. Technologies of piezoelectric sensors, bending plates and load cells are used for a number of applications comprising weigh enforcement, traffic data collection, bridge and tol...

  4. Ultrasonic and eddy current testing of austenitic platings of reactor pressure vessels - qualification according the ENIQ method; Ultraschall- und Wirbelstrompruefung austenitischer Plattierungen von Reaktorbehaeltern - Qualifizierung nach der Methode von ENIQ

    Energy Technology Data Exchange (ETDEWEB)

    Just, T.; Csapo, G. [TUeV NORD SysTec GmbH and Co. KG, Hamburg (Germany); Brenner, W. [TUeV Sueddeutschland-ET, Mannheim (Germany); Waidele, H. [MPA, Univ. Stuttgart (Germany)

    2004-07-01

    In the context of the research project SR2318, which received funds from the Federal Radiation Protection Office (Bundesamt fuer Strahlenschutz) and the BMU, the accuracy of eddy current and ultrasonic tests of austenitic platings on reactor pressure vessels was investigated. The results were evaluated with a view to qualification of combined ultrasonic and eddy current tests of platings and base materials on the one hand; on the other hand, a standard test procedure according to the ENIQ method (European Network of Inspection Qualification) is proposed which can serve as a basis for qualification of test procedures. Summarizing suggestions are made for updating the KTA 3201.4 regulation for recurrent inspections of platings. The results of research project SR 2351 are considered. (orig.) [German] Im Rahmen des vom Bundesamt fuer Strahlenschutz bzw. des BMU gefoerderten Untersuchungsvorhabens SR2318 wurde die Aussagefaehigkeit von Ultraschall- und Wirbelstrompruefungen an austenitischen Plattierungen von Reaktordruckbehaeltern untersucht. Die im Untersuchungsvorhaben erzielten Ergebnisse werden zum einen hinsichtlich der Qualifizierung der Pruefung von Plattierungen und des daran angrenzenden Grundwerkstoffes mittels mechanisierter Ultraschallpruefung in Kombination mit der Wirbelstrompruefung bewertet, und es wird zum anderen beispielhaft ein Muster fuer eine Qualifizierung nach der Methodik von ENIQ (European Network of Inspection Qualification) vorgeschlagen, nach dem kuenftig bei Qualifikationen von Pruefverfahren vorgegangen werden kann. Als Quintessenz werden daraus Vorschlaege zur Ergaenzung der Regel KTA 3201.4 hinsichtlich der wiederkehrenden Pruefungen (WKP) von Plattierungsbereichen formuliert. Dabei sind die Ergebnisse des Untersuchungsvorhabens SR 2351 einbezogen worden. (orig.)

  5. Wave motion in elastic solids

    CERN Document Server

    Graff, Karl F

    1991-01-01

    This highly useful textbook presents comprehensive intermediate-level coverage of nearly all major topics of elastic wave propagation in solids. The subjects range from the elementary theory of waves and vibrations in strings to the three-dimensional theory of waves in thick plates. The book is designed not only for a wide audience of engineering students, but also as a general reference for workers in vibrations and acoustics. Chapters 1-4 cover wave motion in the simple structural shapes, namely strings, longitudinal rod motion, beams and membranes, plates and (cylindrical) shells. Chapter

  6. From an 'ice-see' perspective: The current use, potential and limitations of Structure-from-Motion photogrammetry for cryospheric applications

    Science.gov (United States)

    Westoby, Matthew; Dunning, Stuart; Allan, Mark; Smith, Mark; Quincey, Duncan; Carrivick, Jonathan; Watson, C. Scott

    2016-04-01

    Structure-from-Motion with Multi-View Stereo (SfM-MVS) methods are rapidly becoming the tool of choice for geoscientists who require a relatively low-cost and viable alternative to traditional surveying technologies for characterising the form and short-term evolution of Earth surface landforms and landscapes. Uptake of SfM-MVS methods by workers in the cryospheric science community has been particularly rapid. The choice to use SfM-MVS has many logistical benefits which promote its adoption in remote glacial environments, namely the requirement for little more than a digital camera and proprietary or open-source software for topographic reconstruction, and a surveyed network of ground control to transform the resultant 3D models into a real-world co-ordinate system, if desired. Optionally, a dedicated aerial photography platform (e.g. kite, blimp, multirotor or fixed-wing UAV) may be used for initial photograph acquisition, which can facilitate glacier-scale observation and analysis. To date, cryospheric applications of SfM-MVS have included: the monitoring of glacier, moraine, and rock glacier movement; the evolution of ice cliffs on debris-covered glaciers; the reconstruction of ice-marginal or deglaciated topography; patch- and moraine-scale sedimentological characterisation; and the characterisation of glacier surfaces to monitor supraglacial drainage development or to inform energy balance modelling. This contribution will showcase existing applications and original data and discuss exciting potential opportunities and current limitations of the SfM-MVS method for the cryospheric sciences.

  7. Designing a licence plate for memorability

    NARCIS (Netherlands)

    Schraagen, J.M.C.; Dongen, C.J.G. van

    2005-01-01

    Good memorability of licence plates is important in those cases where licence plates are viewed for a brief period of time and the information is essential for police investigations. The purpose of the current study was to design a new Dutch licence plate that could be remembered well. A memory expe

  8. Create Your Plate

    Medline Plus

    Full Text Available ... A A A Listen En Español Create Your Plate Create Your Plate is a simple and effective ... and that your options are endless. Create Your Plate! Click on the plate sections below to add ...

  9. The Biggest Plates on Earth. Submarine Ring of Fire--Grades 5-6. Plate Tectonics.

    Science.gov (United States)

    National Oceanic and Atmospheric Administration (DOC), Rockville, MD.

    This activity is designed to teach how tectonic plates move, what some consequences of this motion are, and how magnetic anomalies document the motion at spreading centers do. The activity provides learning objectives, a list of needed materials, key vocabulary words, background information, day-to-day procedures, internet connections, career…

  10. A non-classical Mindlin plate model incorporating microstructure, surface energy and foundation effects

    Science.gov (United States)

    Gao, X.-L.; Zhang, G. Y.

    2016-07-01

    A non-classical model for a Mindlin plate resting on an elastic foundation is developed in a general form using a modified couple stress theory, a surface elasticity theory and a two-parameter Winkler-Pasternak foundation model. It includes all five kinematic variables possible for a Mindlin plate. The equations of motion and the complete boundary conditions are obtained simultaneously through a variational formulation based on Hamilton's principle, and the microstructure, surface energy and foundation effects are treated in a unified manner. The newly developed model contains one material length-scale parameter to describe the microstructure effect, three surface elastic constants to account for the surface energy effect, and two foundation parameters to capture the foundation effect. The current non-classical plate model reduces to its classical elasticity-based counterpart when the microstructure, surface energy and foundation effects are all suppressed. In addition, the new model includes the Mindlin plate models considering the microstructure dependence or the surface energy effect or the foundation influence alone as special cases, recovers the Kirchhoff plate model incorporating the microstructure, surface energy and foundation effects, and degenerates to the Timoshenko beam model including the microstructure effect. To illustrate the new Mindlin plate model, the static bending and free vibration problems of a simply supported rectangular plate are analytically solved by directly applying the general formulae derived.

  11. 弥散铜导电条的制备及其组织性能分析%Preparation of ODSC Current-carrying Plate and Analysis of Its Microstructure and Properties

    Institute of Scientific and Technical Information of China (English)

    岳灿甫; 陈会东; 雷竹芳; 金建新; 陈派明

    2012-01-01

    使用雾化法制备铜-铝合金粉,采用内氧化法制备锭坯,热挤压锭坯制备弥散铜棒材,然后经拉伸和轧制棒材法制备弥散铜导电条,并对Al2O3弥散强化铜合金导电条的组织与性能进行了分析.结果表明,制备的弥散铜导电条厚1~25 mm,制备的弥散铜导电条中铝含量分别为0.19%、0.12%; 0.12%Al含量的弥散铜导电条抗拉强度为495 MPa,导电率≥92%IACS;0.19%Al含量的弥散铜导电条抗拉强度为530 MPa,导电率≥87%IACS.%The ingot of aluminum oxide dispersion strengthened copper alloy (ODSC) was produced by using atomized Cu-Al powder by adopting internal oxidation method. The rods were produced by hot extrusion method. The current-carrying plate was produced by cold drawing the rods and then cold rolling. The size of ODSC current-carrying plate was 1 -25 mm. The produced plates had two brand with 0.12%Al, 0.19%Al. Tensile strength of the copper alloy with 0.12%Al is 495 Mpa, and its conductivity is more than 92%1ACS; the tensile strength of the copper alloy with 0.19% Al is 530 Mpa, and its conductivity is 87%IACS.

  12. Plate Tectonics 2.0: Using GPS to Refine Global Crustal Kinematics and Rewrite Textbooks

    Science.gov (United States)

    Kreemer, C.; Blewitt, G.; Stamps, D. S.; Saria, E.

    2015-12-01

    Any model of the Earth's inner workings should be consistent with the observed motion and deformation at its surface. The whole idea that the entire Earth's surface comprises of a dozen or so tectonic plates with no deformation in between them (as most textbooks will tell you) is embarrassingly outdated. The advent of high-precision GNSS measurements of crustal motion has led to the direct observation of plate motion, the confirmation of plate rigidity, and the refinement of crustal kinematics in diffuse plate boundary zones. With the rapidly growing number of continuous GPS (cGPS) stations (as well as campaign-style measurements) some of the earlier results can now be reassessed while at the same time we can continue to quantify the motion and deformation of a large part of the Earth's surface. We present the latest version (v. 2.2) of the Global Strain Rate Model (GSRM), which is almost entirely constrained by horizontal GPS velocities. The model contains the rigid-body rotations of 50 plates as well as strain rate and vorticity estimates at a high spatial resolution for the ~14% of the Earth's surface that is caught up in between the plates. Resulting global or regional maps of dilatation, vorticity, and strain tensor amplitude and style, are poised to augment standard textbook images of plate motions, and we anticipate that they will foster further scientific and educational inquiry. GSRM v2.2 is constrained by >24,000 velocities. Of those ~7900 were determined by us from time-series that we obtained through a routine processing of all globally available RINEX data. Many of these stations were not installed with the intention to track crustal motions, but often are very usable. This station category is currently the biggest contributor to the data explosion; our solution has >1100 more stations compared with the previous solution of just 18 months ago. We transform to our solution GPS velocities from >250 published studies, >30 more than in the previous

  13. Fractional motions

    Energy Technology Data Exchange (ETDEWEB)

    Eliazar, Iddo I., E-mail: eliazar@post.tau.ac.il [Holon Institute of Technology, P.O. Box 305, Holon 58102 (Israel); Shlesinger, Michael F., E-mail: mike.shlesinger@navy.mil [Office of Naval Research, Code 30, 875 N. Randolph St., Arlington, VA 22203 (United States)

    2013-06-10

    Brownian motion is the archetypal model for random transport processes in science and engineering. Brownian motion displays neither wild fluctuations (the “Noah effect”), nor long-range correlations (the “Joseph effect”). The quintessential model for processes displaying the Noah effect is Lévy motion, the quintessential model for processes displaying the Joseph effect is fractional Brownian motion, and the prototypical model for processes displaying both the Noah and Joseph effects is fractional Lévy motion. In this paper we review these four random-motion models–henceforth termed “fractional motions” –via a unified physical setting that is based on Langevin’s equation, the Einstein–Smoluchowski paradigm, and stochastic scaling limits. The unified setting explains the universal macroscopic emergence of fractional motions, and predicts–according to microscopic-level details–which of the four fractional motions will emerge on the macroscopic level. The statistical properties of fractional motions are classified and parametrized by two exponents—a “Noah exponent” governing their fluctuations, and a “Joseph exponent” governing their dispersions and correlations. This self-contained review provides a concise and cohesive introduction to fractional motions.

  14. APPLICATION OF PULSE CURRENT TO THE CRACK-ARREST IN A CONDUCTING PLATE%脉冲电流在导电薄板裂纹止裂技术中的应用

    Institute of Scientific and Technical Information of China (English)

    胡宇达; 白象忠

    2000-01-01

    给出了脉冲电流作用下,无限大薄板中裂纹尖端附近电流密度及焦耳热源功率的表达式,并在此基础上,推得了尖端区域处温度的具体表达式.通过算例证实了,可利用脉冲电流在尖端处产生的热电磁集中效应来抑制裂纹的传播.%The expression of current condensed and power of joule heat source near the crack tip in an infinite thin conducting plate under pulse current is derived, and the expression of temperature around the crack tip is obtained as well. It is confirmed that the spread of the crack can be stopped by the electromagnetic heat effects.

  15. Quantification of local changes in myocardial motion by diffeomorphic registration via currents: application to paced hypertrophic obstructive cardiomyopathy in 2D echocardiographic sequences

    NARCIS (Netherlands)

    Duchateau, N.; Giraldeau, G.; Gabrielli, L.; Fernandez-Armenta, J.; Penela, D.; Evertz, R.; Mont, L.; Brugada, J.; Berruezo, A.; Sitges, M.; Bijnens, B.H.

    2015-01-01

    Time-to-peak measurements and single-parameter observations are cumbersome and often confusing for quantifying local changes in myocardial function. Recent spatiotemporal normalization techniques can provide a global picture of myocardial motion and strain patterns and overcome some of these limitat

  16. [CPM--Continuous Passive Motion: treatment of injured or operated knee-joints using passive movement. A meta-analysis of current literature].

    Science.gov (United States)

    Kirschner, P

    2004-04-01

    There is still a controversial discussion in literature about the use of motor driven splints in knee surgery--as the principle of continuous passive motion, CPM. For this reason it seemed useful for an evaluation to look through the papers which were published since 1990. It was obvious, that negative results were published often before this year, but this papers are still quoted standard works. In medical data bases subito-doc.de, medscape.com, medica.de and zbmed.de 230 papers were found by search CPM, continuous passive motion and arthromot. Coincidentally there was a search for authors who were already quoted in other papers. 36 papers concerning CPM after knee surgery were utilized. The role of CPM regarding the range of motion, swelling, duration of hospital stay, use of analgesics, costs, postoperative manipulations, wound healing and thrombo embolic complications was evaluated. Although the results of this partial retrospective, partial prospective, sometimes randomized or double blinded studies are in contradiction, there can only be found a trend to better results. New clinical studies for evidence based guidelines in the handling of continuous passive motion after knee surgery are necessary.

  17. Air loads on a rigid plate oscillating normal to a fixed surface

    NARCIS (Netherlands)

    Beltman, W.M.; Hoogt, van der P.J.M.; Spiering, R.M.E.J.; Tijdeman, H.

    1997-01-01

    This paper deals with the theoretical and experimental investigation on a rigid, rectangular plate oscillating in the proximity of a fixed surface. The plate is suspended by springs. The airloads generated by the oscillating motion of the plate are determined. Due to the fact that the plate is rigid

  18. Sites and mechanisms of antibiotic-induced neuromuscular block: a pharmacological analysis using quantal content, voltage clamped end-plate currents and single channel analysis.

    Science.gov (United States)

    Fiekers, J F

    1999-01-01

    Since the original observation of Vital Brazil and Corrado (1957) concerning the antibiotic induced neuromuscular block produced by streptomycin, there has been considerable interest in the mechanisms responsible for not only neuromuscular block but also the effects of antibiotics on different systems. We used the voltage clamped end-plate of transacted skeletal muscle to examine the concentration-dependent actions of several groups of antibiotics. The aminoglycoside antibiotics, neomycin and streptomycin, were both more effective at reducing quantal release of acetylcholine (ACh) than interacting with the postjunctional ACh receptor-channel complex. Neomycin was approximately 10 X more potent prejunctionally than streptomycin and the prejunctional effects of each antibiotic were reversed competitively by raising extracellular calcium. Both neomycin and streptomycin also had postjunctional actions at higher concentrations. Neomycin interacted with the open state of the ACh receptor ion channel complex while streptomycin blocks the ACh receptor. The lincosamide antibiotics, lincomycin and clindamycin produced their neuromuscular block postjunctionally by interacting with the open state of the ACh-receptor channel complex. Clindamycin is approximately 20 X more effective at blocking the open channel than was lincomycin. Using cell attached patch clamp recordings in cultured rat myotubes, we demonstrated a lincosamide-induced block of open ion channels with clindamycin having a much slower unblocking rate than lincomycin. Using epimers of the lincosamides, we demonstrated that lipophilicity of the molecule, rather than stereochemical considerations, is important for open channel blockade affecting primarily the "off" rate of channel blocking. This mechanism appears important for not only the lincosamide antibiotics but also for the postjunctional actions of the aminoglycoside antibiotics, particularly neomycin.

  19. Present-day kinematics of the Rivera plate and implications for tectonics in southwestern Mexico

    Science.gov (United States)

    Demets, Charles; Stein, Seth

    1990-01-01

    A model for the present-day motion of the Rivera plate relative to the North America, Cocos, and Pacific plates is derived using new data from the Pacific-Rivera rise and Rivera transform fault, together with new estimates of Pacific-Rivera motions. The results are combined with the closure-consistent NUVEL-1 global plate motion model of DeMets et al. (1990) to examine present-day deformation in southwestern Mexico. The analysis addresses several questions raised in previous studies of the Rivera plate. Namely, do plate motion data from the northern East Pacific rise require a distinct Rivera plate? Do plate kinematic data require the subduction of the Rivera plate along the seismically quiescent Acapulco trench? If so, what does the predicted subduction rate imply about the earthquake recurrence interval in the Jalisco region of southwestern Mexico?

  20. Liquid repellency by a moving plate

    Science.gov (United States)

    Bouillant, Ambre; Anais Gauthier Team; David Quere Team; Christophe Clanet Team

    2016-11-01

    Moving solids can repel impacting drops, owing to their motion. Provided the solid velocity is larger than a threshold value, air entrained at the vicinity of the moving plate prevents the drop from wetting, and makes it bounce. In addition, the rebound is oblique, which enhances the evacuation of liquid. We discuss experiments and models on this theme, and extend them to case of small droplets (such as formed in a spray) found to be even more efficiently repelled by the moving plate.

  1. Current Statues of the Wear Resistance of Electroless Ni-P Based Alloy Plating%化学镀镍磷基合金镀层耐磨性的研究进展

    Institute of Scientific and Technical Information of China (English)

    刘宏; 卞建胜; 李莎; 张彪

    2012-01-01

    化学镀镍磷基合金镀层因硬度高、厚度均匀及耐磨性优异,在工业中得到了广泛应用.简述了化学镀镍磷基合金从二元、三元到复合镀层的发展历程,概述了化学镀镍磷基合金镀层耐磨性的影响因素——合金镀层的化学成分、镀层与基体间的结合力及镀层硬度,并从这三方面论述了改善耐磨性的方法,最后提出了在改善合金镀层耐磨性研究中存在的问题和未来的发展方向.%Electroless Ni-P based alloy platings have found extensive application in industry because of its high hardness, uniform thickness and excellent wear resistance. The development of the electroless Ni-P based alloy platings, from binary and tenary alloy coatings to composite coatings, was summarized, and the influence factors of the wear resistance were presented from the chemical composition of alloy coating, the combining power between coating and matrix and the hardness of coating, as well as current status of improving the wear resistance of electroless plated Ni-P based alloys. At last, the problem exiting in the research of improving the wear resistance of alloy coating and the future research orientation were raised.

  2. Motion analysis report

    Science.gov (United States)

    Badler, N. I.

    1985-01-01

    Human motion analysis is the task of converting actual human movements into computer readable data. Such movement information may be obtained though active or passive sensing methods. Active methods include physical measuring devices such as goniometers on joints of the body, force plates, and manually operated sensors such as a Cybex dynamometer. Passive sensing de-couples the position measuring device from actual human contact. Passive sensors include Selspot scanning systems (since there is no mechanical connection between the subject's attached LEDs and the infrared sensing cameras), sonic (spark-based) three-dimensional digitizers, Polhemus six-dimensional tracking systems, and image processing systems based on multiple views and photogrammetric calculations.

  3. Reducing risk where tectonic plates collide

    Science.gov (United States)

    Gomberg, Joan S.; Ludwig, Kristin A.

    2017-06-19

    Most of the world’s earthquakes, tsunamis, landslides, and volcanic eruptions are caused by the continuous motions of the many tectonic plates that make up the Earth’s outer shell. The most powerful of these natural hazards occur in subduction zones, where two plates collide and one is thrust beneath another. The U.S. Geological Survey’s (USGS) “Reducing Risk Where Tectonic Plates Collide—A USGS Plan to Advance Subduction Zone Science” is a blueprint for building the crucial scientific foundation needed to inform the policies and practices that can make our Nation more resilient to subduction zone-related hazards.

  4. Oscillations of a spring-magnet system damped by a conductive plate

    Science.gov (United States)

    Ladera, C. L.; Donoso, G.

    2013-09-01

    We study the motion of a spring-magnet system that oscillates with very low frequencies above a circular horizontal non-magnetizable conductive plate. The magnet oscillations couple with the plate via the Foucault currents induced therein. We develop a simple theoretical model for this magneto-mechanical oscillator, a model that leads to the equation of a damped harmonic oscillator, whose weak attenuation constant depends upon the system parameters, e.g. the electrical conductivity of the constituent material of the plate and its thickness. We present a set of validating experiments, the results of which are predicted with good accuracy by our analytical model. Additional experiments can be performed with this oscillating system or its variants. This oscillator is simple and low-cost, easy to assemble, and can be used in experiments or project works in physics teaching laboratories at the undergraduate level.

  5. The present-day number of tectonic plates

    Science.gov (United States)

    Harrison, Christopher G. A.

    2016-03-01

    The number of tectonic plates on Earth described in the literature has expanded greatly since the start of the plate tectonic era, when only about a dozen plates were considered in global models of present-day plate motions. With new techniques of more accurate earthquake epicenter locations, modern ways of measuring ocean bathymetry using swath mapping, and the use of space based geodetic techniques, there has been a huge growth in the number of plates thought to exist. The study by Bird (2003) proposed 52 plates, many of which were delineated on the basis of earthquake locations. Because of the pattern of areas of these plates, he suggested that there should be more small plates than he could identify. In this paper, I gather together publications that have proposed a total of 107 new plates, giving 159 plates in all. The largest plate (Pacific) is about 20 % of the Earth's area or 104 Mm2, and the smallest of which (Plate number 5 from Hammond et al. 2011) is only 273 km2 in area. Sorting the plates by size allows us to investigate how size varies as a function of order. There are several changes of slope in the plots of plate number organized by size against plate size order which are discussed. The sizes of the largest seven plates is constrained by the area of the Earth. A middle set of 73 plates down to an area of 97,563 km2 (the Danakil plate at number 80, is the plate of median size) follows a fairly regular pattern of plate size as a function of plate number. For smaller plates, there is a break in the slope of the plate size/plate number plot and the next 32 plates follow a pattern of plate size proposed by the models of Koehn et al. (2008) down to an area of 11,638 km2 (West Mojave plate # 112). Smaller plates do not follow any regular pattern of area as a function of plate number, probably because we have not sampled enough of these very small plates to reveal any clear pattern.

  6. PROPER MOTIONS IN THE GALACTIC BULGE: PLAUT'S WINDOW

    Directory of Open Access Journals (Sweden)

    K. Vieira

    2009-01-01

    Full Text Available A proper motion study of a eld of 20' x20' inside Plaut's low extinction window (l,b=(0 ;-8 , has been completed. Relative proper motions and photographic BV photometry have been derived for -21; 000 stars reaching to V - 20:5 mag, based on the astrometric reduction of 43 photographic plates, spanning over 21 years of epoch di erence. Proper motion errors are typically 1 mas yr-1. Cross-referencing with the 2MASS catalog yielded a sample of - 8700 stars, from which predominantly disk and bulge subsamples were selected photometrically from the JH color-magnitude diagram. The two samples exhibited di erent proper-motion distributions, with the disk displaying the expected re ex solar motion. Galactic rotation was also detected for stars between -2 and -3 kpc from us. The bulge sample, represented by red giants, has an intrinsic proper motion dispersion of (l; b = (3:39; 2:91 = (0:11; 0:09 mas yr-1, which is in good agreement with previous results. A mean distance of 6:37+0:87 -0:77 kpc has been estimated for the bulge sample, based on the observed K magnitude of the horizontal branch red clump. The metallicity [M=H] distribution was also obtained for a subsample of 60 bulge giants stars, based on calibrated photometric indices. The observed [M=H] shows a peak value at [M=H]-0:1 with an extended metal poor tail and around 30% of the stars with supersolar metallicity. No change in proper motion dispersion was observed as a function of [M=H]. We are currently in the process of obtaining CCD UBV RI photometry for the entire proper-motion sample of - 21; 000 stars.

  7. Global Plate Driving Forces at 50Ma

    Science.gov (United States)

    Butterworth, N. P.; Quevedo, L. E.; Müller, R. D.

    2011-12-01

    We apply a novel workflow utilising the BEM-Earth geodynamic software to analyse the global coupled plate-mantle dynamics at 50 Ma. A subduction history model based on kinematic data going as far back as 80 Ma was developed using the GPlates software. Advection of the plates into the mantle takes into account the absolute plate motions and lithospheric thickness derived from its age to produce an estimated density heterogeneity initial model condition in the upper mantle. The resulting global model consists of regions of a mantle viscosity and density structure that is post-processed to ensure smooth non-overlapping 3D surfaces. BEM-Earth is then free to evolve the model toward the 50 Ma solution. The evolution of the model is driven by self-consistent buoyancy driven mantle dynamics. We use the model velocity output to quantify changes in forces driving the plates before and after 50 Ma. We analyse the rapid change in plate motion of India, Africa and plates in the Pacific Ocean basin by considering slab-pull, ridge-push and mantle drag/suction forces that naturally result from such top-down driven mantle flow. We compare the results with plate kinematic reconstructions and other geological observations.

  8. Vibration and Buckling Analysis of Moderately Thick Plates using Natural Element Method

    Directory of Open Access Journals (Sweden)

    Mohammad Etemadi

    2015-07-01

    Full Text Available Using natural element method (NEM, the buckling and the free vibration behaviors of moderate thick plates is studied here. The basis of NEM is natural neighbors and Voronoi cells concepts. The shape functions of nodes located in the domain is equal to the proportion of common natural neighbors area divided by area that related by each Voronoi cells. First step in analyzing the moderate thick plates is identification boundaries. This is done by nodes scattering on problem domain. Mindlin/Reissner theory is used to express the equations of moderate thick plate. First and second order shape functions obtained from natural element method are used to discretize differential equations. Using numerical integration on whole discrete equations of domain, stiffness, geometry and mass matrices of plate are obtained. Buckling loads and vibration modes are expressed by substituting these matrices in plate equations of motions. Arbitrary shapes of plate are selected for solution. Comparing the results of the current approach with those obtained by other numerical analytical methods, it is shown that natural element method can solve problems with complex areas accurately.

  9. 小浪底水库异重流持续运动条件的定量准则%Quantitative criterion of continuous motion conditions of turbid density current in reservoirs

    Institute of Scientific and Technical Information of China (English)

    李书霞; 夏军强; 张俊华; 刘沛清; 王艳平

    2011-01-01

    To release sediment through venting turbid density currents is an important measure to reduce the sedimentation rate in a reservoir,especially at the initial operation stage of the Xiaolangdi Reservoir.A continuous motion criterion of turbidity current is usually used to predict whether turbidity currents can reach the dam after plunging and be vented under various conditions of incoming flow and sediment,and reservoir topography.In this study,existing qualitative criteria for continuous motion conditions of turbid density current are summarized;and shortcomings of existing quantitative criteria are presented.Together with the recent measurements of turbid density currents in the Xiaolangdi Reservoir,a new quantitative criterion is proposed to estimate the continuous motion conditions of turbid density current,which can be described by a relationship between mean stream power and mean water depth in the reservoir.This method can account for the effects of various influencing factors,including the influence of reservoir topography on the continuous motion conditions.%异重流排沙是小浪底水库拦沙初期减少库区泥沙淤积的重要运用方式,异重流持续运动条件用于判断在不同水沙条件及库区地形条件下异重流能否运行到坝前而排出水库,是异重流排沙规律的主要研究内容之一.系统地总结了定性描述异重流持续运动条件的五方面内容,然后分析了现有异重流持续运动条件定量估计方法的不足.结合近年来小浪底水库异重流运行的观测资料,提出了用水流功率与库区平均水深定量表示异重流持续运动的临界条件,这种方法不仅考虑因素较为全面,而且能够充分反映库区地形特征对异重流持续运动的影响.

  10. Neogene Caribbean plate rotation and associated Central American tectonic evolution

    Science.gov (United States)

    Wadge, G.; Burke, K.

    1983-01-01

    A theoretical model of the opening of the Cayman Trough is developed on the basis of geological evidence from a wide area. It is proposed that strike slip motion began about 30 Myr ago and proceeded at a rate of 37 + or - 6 mm/yr for a total of 1100 km of relative plate displacement, and that Central America Underwent an anticlockwise rotation with internal plate deformation. Maps of the reconstructed motion are provided.

  11. Neogene Caribbean plate rotation and associated Central American tectonic evolution

    Science.gov (United States)

    Wadge, G.; Burke, K.

    1983-01-01

    A theoretical model of the opening of the Cayman Trough is developed on the basis of geological evidence from a wide area. It is proposed that strike slip motion began about 30 Myr ago and proceeded at a rate of 37 + or - 6 mm/yr for a total of 1100 km of relative plate displacement, and that Central America Underwent an anticlockwise rotation with internal plate deformation. Maps of the reconstructed motion are provided.

  12. Correcting for systematic effects in ground-based photographic proper motions: The Southern Proper Motion Program as a case study

    Science.gov (United States)

    van Altena, William F.; Girard, T. M.; Platais, I.; Kozhurina-Platais, V.; López, C. E.

    The derivation of accurate positions and proper motions from ground-based photographic materials requires the minimization of systematic errors due to inaccurate modeling of the telescopes' field-of-view and the magnitude equation. We describe the procedures that have been developed for the Southern Proper Motions Program (SPM) to deal with these important problems. The SPM is based on photographic plates taken at our Carlos Cesco Observatory at El Leoncito, Argentina and will yield absolute proper motions and positions to magnitude B approximately 19 for approximately 1 million stars south of declination -20 degrees. The SPM is a joint program between the Yale Southern Observatory and the Universidad Nacional de San Juan, Argentina. The SPM Catalog 2.0, which is the current version covering the -25 to -40 degree declination zones, provides positions, absolute proper motions, and photographic BV photometry for over 320,000 stars and galaxies. Stars cover the magnitude range 5 astrom/. Our web-side contains several useful plots showing the sky coverage, error distribution, a quick comparison with the Hipparcos proper motions, etc. We would appreciate your comments on the SPM 2.0 and our Web page.

  13. Global crustal movement and tectonic plate boundary deformation constrained by the ITRF2008

    Directory of Open Access Journals (Sweden)

    Zhu Ze

    2012-08-01

    Full Text Available On the basis of the newly released International Terrestrial Reference Frame(ITRF2008 by the International Earth Rotation Service (IERS, a new global plate model ITRF2008 plate for the major plates is established. This ITRF2008-derived model is analyzed in comparison with NNR-NUVEL1A model, which is mainly based on geological and geophysical data. The Eurasia and Pacific plates display obvious differences in terms of the velocity fields derived from the two plate motion models. Plate acceleration is also introduced to characterize the differences of the two velocity fields which obtained from ITRF2008 -plate and NNR-NUVEL1A models for major individual plates. The results show that the Africa, South America and Eurasia plates are undergoing acceleration, while the North America and Australia plates are in the state of deceleration motion.

  14. Inevitability of Plate Tectonics on Super-Earths

    CERN Document Server

    Valencia, Diana; Sasselov, Dimitar D

    2007-01-01

    The recent discovery of super-Earths (masses less or equal to 10 earth-masses) has initiated a discussion about conditions for habitable worlds. Among these is the mode of convection, which influences a planet's thermal evolution and surface conditions. On Earth, plate tectonics has been proposed as a necessary condition for life. Here we show, that super-Earths will also have plate tectonics. We demonstrate that as planetary mass increases, the shear stress available to overcome resistance to plate motion increases while the plate thickness decreases, thereby enhancing plate weakness. These effects contribute favorably to the subduction of the lithosphere, an essential component of plate tectonics. Moreover, uncertainties in achieving plate tectonics in the one earth-mass regime disappear as mass increases: super-Earths, even if dry, will exhibit plate tectonic behaviour.

  15. Pulse plating

    CERN Document Server

    Hansal, Wolfgang E G; Green, Todd; Leisner, Peter; Reichenbach, Andreas

    2012-01-01

    The electrodeposition of metals using pulsed current has achieved practical importance in recent years. Although it has long been known that changes in potential, with or without polarity reversal, can significantly affect the deposition process, the practical application of this has been slow to be adopted. This can largely be explained in terms of the complex relationship between the current regime and its effect on the electrodeposition process. In order to harness these effects, an understanding of the anodic and cathodic electrochemical processes is necessary, together with the effects of polarity reversal and the rate of such reversals. In this new monograph, the basics of metal electrodeposition from solution are laid out in great detail in seven distinct chapters. With this knowledge, the reader is able to predict how a given pulse train profile can be adopted to achieve a desired outcome. Equally important is the choice of a suitable rectifier and the ancillary control circuits to enable pulse platin...

  16. Magnetohydrodynamic free convection between vertical parallel porous plates in the presence of induced magnetic field.

    Science.gov (United States)

    Sarveshanand; Singh, A K

    2015-01-01

    In this paper, the steady two-dimensional hydromagnetic free convective flow of an incompressible viscous and electrically conducting fluid between two parallel vertical porous plates has been considered. The effect of induced magnetic field arising due to the motion of an electrically conducting fluid is taken into account. The governing equations of the motion are a set of simultaneous ordinary differential equations and their analytical solutions in dimensionless form have been obtained for the velocity field, the induced magnetic field and the temperature field. The expression for the induced current density has been also obtained. The effects of various non-dimensional parameters on the velocity profile, the induced magnetic field profile, the temperature profile and the induced current density profile have been shown in the graphs. It is found that the effect of suction parameter is to decrease the velocity field and induced current density while it has increasing effect on the induced magnetic field.

  17. Inversion for the driving forces of plate tectonics

    Science.gov (United States)

    Richardson, R. M.

    1983-01-01

    Inverse modeling techniques have been applied to the problem of determining the roles of various forces that may drive and resist plate tectonic motions. Separate linear inverse problems have been solved to find the best fitting pole of rotation for finite element grid point velocities and to find the best combination of force models to fit the observed relative plate velocities for the earth's twelve major plates using the generalized inverse operator. Variance-covariance data on plate motion have also been included. Results emphasize the relative importance of ridge push forces in the driving mechanism. Convergent margin forces are smaller by at least a factor of two, and perhaps by as much as a factor of twenty. Slab pull, apparently, is poorly transmitted to the surface plate as a driving force. Drag forces at the base of the plate are smaller than ridge push forces, although the sign of the force remains in question.

  18. Inversion for the driving forces of plate tectonics

    Science.gov (United States)

    Richardson, R. M.

    1983-01-01

    Inverse modeling techniques have been applied to the problem of determining the roles of various forces that may drive and resist plate tectonic motions. Separate linear inverse problems have been solved to find the best fitting pole of rotation for finite element grid point velocities and to find the best combination of force models to fit the observed relative plate velocities for the earth's twelve major plates using the generalized inverse operator. Variance-covariance data on plate motion have also been included. Results emphasize the relative importance of ridge push forces in the driving mechanism. Convergent margin forces are smaller by at least a factor of two, and perhaps by as much as a factor of twenty. Slab pull, apparently, is poorly transmitted to the surface plate as a driving force. Drag forces at the base of the plate are smaller than ridge push forces, although the sign of the force remains in question.

  19. Determination of Euler parameters of Philippine Sea plate and the inferences

    Institute of Scientific and Technical Information of China (English)

    ZANG; Shaoxian

    2002-01-01

    [1]Seno, T., The instantaneous rotation vector of the Philippine Sea Plate relative to the Eurasia plate, Tectonophysics, 1977, 42: 209-226.[2]Chase, C. G., Plate kinematics: The Americas, East Africa, and the rest of the world, Earth Planet Sci. Lett., 1978, 37: 355-368.[3]Minster, J. B., Jordan, T. H., Rotation vectors for the Philippine and Rivera plates, Eos. Trans. AGU, 1978, 60: 958.[4]Karig, D. E., Basin genesis in the Philippine Sea, Initial Rep. Deep Sea Drill Proj., 1975, 31: 857-879.[5]Ranken, B., Cardwell, R. K., Karig, D. E., Kinematics of the Philippine Sea plate, Tectonics, 1984, 3: 555-575.[6]Huchon, P., Comments on "Kinematics of the Philippine Sea plate" (eds. Branken, R. K., Cardwell, Karig, D. E.) Tecton-ics, 1986, 5: 165-168.[7]Weissel, J. K., Anderson, R. N., Is there Caroline plate? Earth Planet Sci. Lett., 1978, 41: 143-158.[8]Seno, T., Seth, S., Alice, E. G., A model for the motion of the Philippine Sea plate consistent with NUVEL-1 and Geological Data, J. Geophys. Res., 1993, 98: (B10): 17941-17948.[9]DeMets, C., Gordon, R. G., Argus, D. F. et al., Current plate motions, Geophys. J. Intel., 1990, 101: 425-478.[10]Zhu, W. Y., Cheng, Z. Y., Xiong, Y. Q. et al., Preliminary results of measuring the crustal deformation in Qinghai-Xizang area using GPS technique, Scence in China, Ser. D, 1998, 41(3): 314-318.[11]Zhu, W. Y., Wang, X. Y., Cheng, Z. Y. et al., Crustal motion of Chinese mainland monitored by GPS, Science in China, Ser. D, 2000, 43(4): 394-400.[12]Seno, T., Moriyama, T., Stein, S. et al., Redetermination of the Philippine sea plate motion (abstract), EOS Trans. Am. Geophysics Res., 1987, 68: 1474.[13]Yu, S. B., Kuo, L. C., GPS observation of crustal deformation in the Taiwan-Luzon region, Geophysical Res. Lett., 1999, 26(7): 923-926.[14]Yu, S. B., Chen, H. Y., Kuo, L. C., Velocity field of GPS station in the Taiwan area, Tectonophysics, 1997, 274: 41-59.[15]Kato, T., Kotake

  20. Investigating the Optimum Efficiency of Acoustoelectric Conversion Plate Devices

    Directory of Open Access Journals (Sweden)

    Chien-Chih Chen

    2014-04-01

    Full Text Available This study aims to develop the acoustoelectric conversion plate in terms of electromagnetic induction law to convert sound energy to electricity, where the developed apparatus is made of three parts, the thin film coil, the spring, and the high-intensity magnetic framework. In process, the thin film coil receives the injecting sound vibration in connection with the spring to cause the reciprocating motion between the coil and the high-intensity magnet, which yields the electromotive force (EMF. In this study, a pearl plate of length 95 mm, width 95 mm, and thickness 1.5 mm adhered with a PET film of thickness 0.08mm is built as the substrate plate due to it has good properties of light and elasticity. In connection with the substrate plate and the electric coil is the thin film coil. Experiments used the speaker with output frequencies of 30~156 Hz and sound power of 0.5 W (sound intensity 0.32 W/m2, sound pressure level 115 dB as the sound source. The sound energy is captured by the acoustoelectric conversion plate for working efficiency and optimization parameters analysis. The studied parameters content of diameter, turns, and width of electric coil as well as distance between high intensity magnet and coil. The results show that diameter 0.11 mm, turns 220, and width 3 mm of the electric coil, in connection with steel spring of diameter 0.2 mm while input sound is 30 Hz, receives the average output voltage of 0.57 V, the average output current of 5.46 mA, the average output power of 3.13 mW, and the sound electric conversion efficiency of 0.63%. This innovation device could be used in highway, near waterfalls, and some high noise factories to capture energy for immediately charging cell-phone to save human life.

  1. High-frequency techniques for RCS prediction of plate geometries and a physical optics/equivalent currents model for the RCS of trihedral corner reflectors, parts 1 and 2

    Science.gov (United States)

    Balanis, Constantine A.; Polka, Lesley A.; Polycarpou, Anastasis C.

    Formulations for scattering from the coated plate and the coated dihedral corner reflector are included. A coated plate model based upon the Uniform Theory of Diffraction (UTD) for impedance wedges was presented in the last report. In order to resolve inaccuracies and discontinuities in the predicted patterns using the UTD-based model, an improved model that uses more accurate diffraction coefficients is presented. A Physical Optics (PO) model for the coated dihedral corner reflector is presented as an intermediary step in developing a high-frequency model for this structure. The PO model is based upon the reflection coefficients for a metal-backed lossy material. Preliminary PO results for the dihedral corner reflector suggest that, in addition to being much faster computationally, this model may be more accurate than existing moment method (MM) models. An improved Physical Optics (PO)/Equivalent Currents model for modeling the Radar Cross Section (RCS) of both square and triangular, perfectly conducting, trihedral corner reflectors is presented. The new model uses the PO approximation at each reflection for the first- and second-order reflection terms. For the third-order reflection terms, a Geometrical Optics (GO) approximation is used for the first reflection; and PO approximations are used for the remaining reflections. The previously reported model used GO for all reflections except the terminating reflection. Using PO for most of the reflections results in a computationally slower model because many integrations must be performed numerically, but the advantage is that the predicted RCS using the new model is much more accurate. Comparisons between the two PO models, Finite-Difference Time-Domain (FDTD) and experimental data are presented for validation of the new model.

  2. Amplification of acoustic waves in laminated piezoelectric semiconductor plates

    Energy Technology Data Exchange (ETDEWEB)

    Yang, J.S.; Yang, X.M.; Turner, J.A. [University of Nebraska, Department of Engineering Mechanics, Lincoln, NE (United States)

    2004-12-01

    Two-dimensional equations for coupled extensional, flexural and thickness-shear motions of laminated plates of piezoelectric semiconductors are obtained systematically from the three-dimensional equations by retaining lower order terms in power series expansions in the plate thickness coordinate. The equations are used to analyze extensional waves in a composite plate of piezoelectric ceramics and semiconductors. Dispersion and dissipation due to semiconduction as well as wave amplification by a dc electric field are discussed. (orig.)

  3. Processless offset printing plates

    Directory of Open Access Journals (Sweden)

    Sanja Mahović Poljaček

    2015-06-01

    Full Text Available With the implementation of platesetters in the offset printing plate making process, imaging of the printing plate became more stable and ensured increase of the printing plate quality. But as the chemical processing of the printing plates still highly influences the plate making process and the graphic reproduction workflow, development of printing plates that do not require chemical processing for offset printing technique has been one of the top interests in graphic technology in the last few years. The main reason for that came from the user experience, where majority of the problems with plate making process could be connected with the chemical processing of the printing plate. Furthermore, increased environmental standards lead to reducing of the chemicals used in the industrial processes. Considering these facts, different types of offset printing plates have been introduced to the market today. This paper presents some of the processless printing plates.

  4. Barrel organ of plate tectonics - a new tool for outreach and education

    Science.gov (United States)

    Broz, Petr; Machek, Matěj; Šorm, Zdar

    2016-04-01

    Plate tectonics is the major geological concept to explain dynamics and structure of Earth's outer shell, the lithosphere. In the plate tectonic theory processes in the Earth lithosphere and its dynamics is driven by the relative motion and interaction of lithospheric plates. Geologically most active regions on Earth often correlate with the lithospheric plate boundaries. Thus for explaining the earth surface evolution, mountain building, volcanism and earthquake origin it is important to understand processes at the plate boundaries. However these processes associated with plate tectonics usually require significant period of time to take effects, therefore, their entire cycles cannot be directly observed in the nature by humans. This makes a challenge for scientists studying these processes, but also for teachers and popularizers trying to explain them to students and to the general public. Therefore, to overcome this problem, we developed a mechanical model of plate tectonics enabling demonstration of most important processes associated with plate tectonics in real time. The mechanical model is a wooden box, more specifically a special type of barrel organ, with hand painted backdrops in the front side. These backdrops are divided into several components representing geodynamic processes associated with plate tectonics, specifically convective currents occurring in the mantle, sea-floor spreading, a subduction of the oceanic crust under the continental crust, partial melting and volcanism associated with subduction, a formation of magmatic stripes, an ascent of mantle plume throughout the mantle, a volcanic activity associated with hot spots, and a formation and degradation of volcanic islands on moving lithospheric plate. All components are set in motion by a handle controlled by a human operator, and the scene is illuminated with colored lights controlled automatically by an electric device embedded in the box. Operation of the model may be seen on www

  5. Current surges and seabed erosion near the shelf break in the Canadian Beaufort Sea: A response to wind and ice motion stress

    Science.gov (United States)

    Forest, Alexandre; Osborne, Philip D.; Curtiss, Gregory; Lowings, Malcolm G.

    2016-08-01

    Estimating the erosion potential of seabed sediments and the magnitude of the resulting suspended load in relation to current dynamics near the shelf break is a key issue for better understanding shelf-slope sediment transport. On the outer Mackenzie Shelf (Canadian Beaufort Sea, Arctic Ocean), a thin and discontinuous veneer of recent surficial clays overlie old glaciomarine sediments that further pinch out at the shelf edge. Gas and fluid venting is known to underlie part of sediment instability in the area, but recent mooring-based measurements also indicate that sediments near the shelf break are recurrently remobilized by strong subsurface currents. Here, we relate storms to the development of current surges that resulted in the abrupt resuspension of sediments at two locations along the shelf break. Near-bottom concentrations of suspended sediments were estimated using the acoustic backscatter of high-frequency acoustic Doppler current profilers deployed from September 2011 to September 2013 as part of the Beaufort Regional Environmental Assessment (BREA) program. Near-bottom currents near the shelf edge (140 to 150 m isobaths) were characterized by recurring episodes of elevated velocities (instantaneous speeds up to ~ 40-50 cm s-1) that were extensions of current surges (~ 60-80 cm s-1) occurring in the core of the shelfbreak jet located at ca. 90-120 m. Sudden peaks in suspended sediments (above 100 g m-3) corresponded closely with current surges in the near-bottom boundary layer (fade, such as during the major ice fracturing events of January to March 2013 that were associated with strong and persistent current speeds.

  6. Creation of the Cocos and Nazca plates by fission of the Farallon plate

    Science.gov (United States)

    Lonsdale, Peter

    2005-08-01

    Throughout the Early Tertiary the area of the Farallon oceanic plate was episodically diminished by detachment of large and small northern regions, which became independently moving plates and microplates. The nature and history of Farallon plate fragmentation has been inferred mainly from structural patterns on the western, Pacific-plate flank of the East Pacific Rise, because the fragmented eastern flank has been subducted. The final episode of plate fragmentation occurred at the beginning of the Miocene, when the Cocos plate was split off, leaving the much reduced Farallon plate to be renamed the Nazca plate, and initiating Cocos-Nazca spreading. Some Oligocene Farallon plate with rifted margins that are a direct record of this plate-splitting event has survived in the eastern tropical Pacific, most extensively off northern Peru and Ecuador. Small remnants of the conjugate northern rifted margin are exposed off Costa Rica, and perhaps south of Panama. Marine geophysical profiles (bathymetric, magnetic and seismic reflection) and multibeam sonar swaths across these rifted oceanic margins, combined with surveys of 30-20 Ma crust on the western rise-flank, indicate that (i) Localized lithospheric rupture to create a new plate boundary was preceded by plate stretching and fracturing in a belt several hundred km wide. Fissural volcanism along some of these fractures built volcanic ridges (e.g., Alvarado and Sarmiento Ridges) that are 1-2 km high and parallel to "absolute" Farallon plate motion; they closely resemble fissural ridges described from the young western flank of the present Pacific-Nazca rise. (ii) For 1-2 m.y. prior to final rupture of the Farallon plate, perhaps coinciding with the period of lithospheric stretching, the entire plate changed direction to a more easterly ("Nazca-like") course; after the split the northern (Cocos) part reverted to a northeasterly absolute motion. (iii) The plate-splitting fracture that became the site of initial Cocos

  7. Reliability assessment of different plate theories for elastic wave propagation analysis in functionally graded plates.

    Science.gov (United States)

    Mehrkash, Milad; Azhari, Mojtaba; Mirdamadi, Hamid Reza

    2014-01-01

    The importance of elastic wave propagation problem in plates arises from the application of ultrasonic elastic waves in non-destructive evaluation of plate-like structures. However, precise study and analysis of acoustic guided waves especially in non-homogeneous waveguides such as functionally graded plates are so complicated that exact elastodynamic methods are rarely employed in practical applications. Thus, the simple approximate plate theories have attracted much interest for the calculation of wave fields in FGM plates. Therefore, in the current research, the classical plate theory (CPT), first-order shear deformation theory (FSDT) and third-order shear deformation theory (TSDT) are used to obtain the transient responses of flexural waves in FGM plates subjected to transverse impulsive loadings. Moreover, comparing the results with those based on a well recognized hybrid numerical method (HNM), we examine the accuracy of the plate theories for several plates of various thicknesses under excitations of different frequencies. The material properties of the plate are assumed to vary across the plate thickness according to a simple power-law distribution in terms of volume fractions of constituents. In all analyses, spatial Fourier transform together with modal analysis are applied to compute displacement responses of the plates. A comparison of the results demonstrates the reliability ranges of the approximate plate theories for elastic wave propagation analysis in FGM plates. Furthermore, based on various examples, it is shown that whenever the plate theories are used within the appropriate ranges of plate thickness and frequency content, solution process in wave number-time domain based on modal analysis approach is not only sufficient but also efficient for finding the transient waveforms in FGM plates.

  8. Algorithmic Issues in Modeling Motion

    DEFF Research Database (Denmark)

    Agarwal, P. K; Guibas, L. J; Edelsbrunner, H.

    2003-01-01

    This article is a survey of research areas in which motion plays a pivotal role. The aim of the article is to review current approaches to modeling motion together with related data structures and algorithms, and to summarize the challenges that lie ahead in producing a more unified theory...

  9. Plate Tectonic Cycle. K-6 Science Curriculum.

    Science.gov (United States)

    Blueford, J. R.; And Others

    Plate Tectonics Cycle is one of the units of a K-6 unified science curriculum program. The unit consists of four organizing sub-themes: (1) volcanoes (covering formation, distribution, and major volcanic groups); (2) earthquakes (with investigations on wave movements, seismograms and sub-suface earth currents); (3) plate tectonics (providing maps…

  10. One dimension spring supported ball on top of a sinusoidal vibrating plate: A forced oscillation simulation using molecular dynamics method

    CERN Document Server

    Viridi, Sparisoma; Hidayat, Wahyu; Singarimbun, Alamta; Balkis, Sitti

    2011-01-01

    A ball supported by a spring is set on top of a plate which is sinusoidal vibrated. The motion is limited to one dimension motion. It is assumed that the spring is an ideal one with zero mass. The vibrating plate is considered much heavier than the ball, so that the ball motion has no influence on the plate motion. Plate vibration frequency is varied around the frequency of ball-spring system. Resonance phenomenon is reported, which needs a phase match condition to occur.

  11. Wave Damping over a Perforated Plate with Water Chambers

    Institute of Scientific and Technical Information of China (English)

    ZHU Shutang

    2006-01-01

    The movement of waves propagating over a horizontally submerged perforated plate with waterfilled chambers bellow the plate was investigated by using linear potential theory. The analytical solution was compared with laboratory experiments on wave blocking. The analysis of the wave energy dissipation on the perforated bottom surface shows that the effects of the perforated plate on thewave motion depend mainly on the plate porosity, the wave height, and the wave period. The wave number is a complex number when the wave energy dissipation on the perforated plate is considered. The real part of the wave number refers to the spatial periodicity while the imaginary part represents the damping modulus. The characteristics of the wave motion were explored for several possible conditions.

  12. Collaborative study comparing the spiral plate and aerobic plate count methods.

    Science.gov (United States)

    Gilchrist, J E; Donnelly, C B; Peeler, J T; Campbell, J E

    1977-07-01

    The spiral plate count method is a semiautomated plating technique that greatly reduces manpower and material costs normally associated with the pour plating technique. In this collaborative study, 8 laboratories compared the spiral and pour plating techniques, using 4 samples each of 3 products: frozen pumpkin pie, frozen chicken pot pie, and shampoo. The results show that 10 of the 12 comparisons of means of the pour and spiral methods were not significantly different; 2 values were significant at alpha = 0.01. Overall, the components of variance were less than that of the current milk standard, and the replicate per cent coefficient of variation was satisfactory. This study indicates that the spiral plate method is an acceptable alternative to the pour plate method; the spiral plate method has been adopted as official first action.

  13. Weigh - in - motion (WIM

    Directory of Open Access Journals (Sweden)

    Todorović Neven B.

    2014-01-01

    Full Text Available The biggest wealth of every country lies in its transportation infrastructure so the protection of negative impacts on infrastructure must be provided. The progress of sensor technology proposes today several types of weigh-in-motion systems, which have been tested for their efficiency, accuracy and cost-effectiveness. Technologies of piezoelectric sensors, bending plates and load cells are used for a number of applications comprising weigh enforcement, traffic data collection, bridge and toll control systems and so on. Advantages of using WIM technology are various and its benefits affects all road users (transport companies, public, public transport authorities. Potential of WIM application has been recognized in the leading EU countries, so the existence of the numerous WIM projects.

  14. Analysis on Eddy Current Thermal Effect of the Rigid Conductive Thin Plate Under Multi-pulse Magnetic Field%多脉冲磁场下刚性导电薄板涡电流热效应分析

    Institute of Scientific and Technical Information of China (English)

    张建平; 戴咏夏

    2009-01-01

    针对处于多脉冲磁场下感应加热系统装置中的刚性导电薄板,基于麦克斯韦电磁场方程组及导热微分方程,建立了涡电流场和温度场的理论模型.对涡电流初边值问题及由涡电流热效应引起的温度场定解问题的空间部分采用有限元法,时间部分采用Crank-Nicolson法,给出了计算程序的求解步骤,并进行了定量模拟.仿真结果表明,脉冲次数使得构件的涡电流和温度逐步增加,随后其大小趋于稳定的值,而后来的周期性脉冲只不过是保持这个恒定值不衰减.该结论为电磁感应加热设备的革新改造提供了有效的技术参考.%Based on Maxwell's equations and the thermal conduction differential equation, a theoretical model for rigid conductive thin plate of induction-heating system under multi-pulse magnetic field was established with eddy current field and temperature field included. The numerical steps of algorithm routine along with quantitative simulation were given by adopting the finite element method for the spatial part in the eddy current initial boundary-value problem and the determining-solution problem of temperature field arisen from eddy current thermal effect, and the Crank-Nicolson methods for the time part. The simulation results indicate that the eddy current and the temperature increase with the pulse times, and tend to stable values,thereafter seasonal impulses just only to keep this constant value not diminishing. It provides effective technical reference for innovation of the electromagnetic induction-heating equipment.

  15. Flow of nanofluid past a Riga plate

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Adeel, E-mail: adeelahmed@comsats.edu.pk [Department of Mathematics, COMSATS Institute of Information Technology, Park Road, Chak Shahzad, 44000 Islamabad (Pakistan); Laboratoire J.A. Dieudonné, Université de Nice Sophia Antipolis, Parc Valrose, 06108 Nice (France); Asghar, Saleem [Department of Mathematics, COMSATS Institute of Information Technology, Park Road, Chak Shahzad, 44000 Islamabad (Pakistan); Department of Mathematics, King Abdul Aziz University, Jeddah (Saudi Arabia); Afzal, Sumaira [Department of Mathematics, COMSATS Institute of Information Technology, Park Road, Chak Shahzad, 44000 Islamabad (Pakistan)

    2016-03-15

    This paper studies the mixed convection boundary layer flow of a nanofluid past a vertical Riga plate in the presence of strong suction. The mathematical model incorporates the Brownian motion and thermophoresis effects due to nanofluid and the Grinberg-term for the wall parallel Lorentz force due to Riga plate. The analytical solution of the problem is presented using the perturbation method for small Brownian and thermophoresis diffusion parameters. The numerical solution is also presented to ensure the reliability of the asymptotic method. The comparison of the two solutions shows an excellent agreement. The correlation expressions for skin friction, Nusselt number and Sherwood number are developed by performing linear regression on the obtained numerical data. The effects of nanofluid and the Lorentz force due to Riga plate, on the skin friction are discussed. - Highlights: • Mixed convection flow of a nanofluid past a vertical Riga plate. • The Brownian motion and thermophoresis effects due to nanofluid are incorporated. • Grinberg-term represents the wall parallel Lorentz force due to Riga plate. • The correlation expressions for skin friction, Nusselt and Sherwood numbers are developed. • The effects of nanofluid and the Lorentz force on the skin friction are discussed.

  16. Create Your Plate

    Medline Plus

    Full Text Available ... steps to get started: Using your dinner plate, put a line down the middle of the plate. ... vegetables . Now in one of the small sections, put grains and starchy foods. See this list of ...

  17. Create Your Plate

    Medline Plus

    Full Text Available ... Your Plate It's simple and effective for both managing diabetes and losing weight. Creating your plate lets ... 2016 Articles from Diabetes Forecast® magazine: wcie-meal-planning, In this section Food Planning Meals Diabetes Meal ...

  18. Create Your Plate

    Medline Plus

    Full Text Available ... Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart-Healthy Foods Holiday Meal ... Healthy Diet Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook ...

  19. Food guide plate

    Science.gov (United States)

    ... chips or cookies. VEGETABLES: MAKE HALF OF YOUR PLATE FRUITS AND VEGETABLES Vegetables can be raw, fresh, ... as a snack. FRUITS: MAKE HALF OF YOUR PLATE FRUITS AND VEGETABLES Fruits can be fresh, canned, ...

  20. Growth Plate Fractures

    Science.gov (United States)

    ... the most widely used by doctors is the Salter-Harris system, described below. Type I Fractures These ... incidence of growth plate fractures peaks in adolescence. Salter-Harris classification of growth plate fractures. AAOS does ...

  1. Create Your Plate

    Medline Plus

    Full Text Available ... Planning Meals Diabetes Meal Plans Create Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook ... Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook with Heart- ...

  2. Create Your Plate

    Medline Plus

    Full Text Available ... Planning Meals Diabetes Meal Plans Create Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook ... Create Your Plate Meal Planning for Vegetarian Diets Gluten Free Diets Holiday Meal Planning Cook with Heart- ...

  3. Create Your Plate

    Medline Plus

    Full Text Available ... Your Plate It's simple and effective for both managing diabetes and losing weight. Creating your plate lets you still choose the foods you want, but changes the portion sizes so you are getting larger ...

  4. Create Your Plate

    Medline Plus

    Full Text Available ... Your Plate It's simple and effective for both managing diabetes and losing weight. Creating your plate lets ... Sleeve Custom jerseys for your Tour de Cure team benefits the cause. Ask the Experts: Learn to ...

  5. GENERALIZED VARIATIONAL PRINCIPLESFOR VISCOELASTIC THIN AND THICK PLATES WITH DAMAGE

    Institute of Scientific and Technical Information of China (English)

    ShengDongfa; ChengChangjun

    2004-01-01

    From the constitutive model with generalized force fields for a viscoelastic body with damage, the differential equations of motion for thin and thick plates with damage are derived under arbitrary boundary conditions. The convolution-type functionals for the bending of viscoelastic thin and thick plates with damage are presented, and the corresponding generalized variational principles are given. From these generalized principles, all the basic equations of the displacement and damage variables and initial and boundary conditions can be deduced. As an example, we compare the difference between the dynamical properties of plates with and without damage and consider the effect of damage on the dynamical properties of plates.

  6. Field-driven domain wall motion under a bias current in the creep and flow regimes in Pt/[CoSiB/Pt]N nanowires.

    Science.gov (United States)

    Choi, Y H; Yoshimura, Y; Kim, K-J; Lee, K; Kim, T W; Ono, T; You, C-Y; Jung, M H

    2016-03-31

    The dynamics of magnetic domain wall (DW) in perpendicular magnetic anisotropy Pt/[CoSiB/Pt]N nanowires was studied by measuring the DW velocity under a magnetic field (H) and an electric current (J) in two extreme regimes of DW creep and flow. Two important findings are addressed. One is that the field-driven DW velocity increases with increasing N in the flow regime, whereas the trend is inverted in the creep regime. The other is that the sign of spin current-induced effective field is gradually reversed with increasing N in both DW creep and flow regimes. To reveal the underlying mechanism of new findings, we performed further experiment and micromagnetic simulation, from which we found that the observed phenomena can be explained by the combined effect of the DW anisotropy, Dzyaloshinskii-Moriya interaction, spin-Hall effect, and spin-transfer torques. Our results shed light on the mechanism of DW dynamics in novel amorphous PMA nanowires, so that this work may open a path to utilize the amorphous PMA in emerging DW-based spintronic devices.

  7. Moire interferometry for vibration analysis of plates

    Science.gov (United States)

    Asundi, A.; Cheung, M. T.

    1987-12-01

    Moire interferometry is used to locate nodal regions and measure vibration amplitudes of sinusoidally vibrating square plates. The high sensitivity afforded by this technique makes possible the study of plate vibrations at high frequencies and low amplitudes. The initial pattern is modulated by the zero-order Bessel function representing the vibratory motion. The fringe (or fringes) with best contrast indicate the nodal regions, while the higher order fringes, describing loci of points vibrating with the same amplitude, have decreasing contrast which is improved by spatial filtering.

  8. Create Your Plate

    Medline Plus

    Full Text Available ... Reset Plate Share Create Your Plate ! Share: Seven Simple Steps to Create Your Plate It's simple and effective for both managing diabetes and losing ... en.html Have Type 2 Diabetes? Our free program will help you live well. More from diabetes. ...

  9. Obliquity along plate boundaries

    Science.gov (United States)

    Philippon, Mélody; Corti, Giacomo

    2016-12-01

    Most of the plate boundaries are activated obliquely with respect to the direction of far field stresses, as roughly only 8% of the plate boundaries total length shows a very low obliquity (ranging from 0 to 10°, sub-orthogonal to the plate displacement). The obliquity along plate boundaries is controlled by (i) lateral rheological variations within the lithosphere and (ii) consistency with the global plate circuit. Indeed, plate tectonics and magmatism drive rheological changes within the lithosphere and consequently influence strain localization. Geodynamical evolution controls large-scale mantle convection and plate formation, consumption, and re-organization, thus triggering plate kinematics variations, and the adjustment and re-orientation of far field stresses. These geological processes may thus result in plate boundaries that are not perpendicular but oblique to the direction of far field stresses. This paper reviews the global patterns of obliquity along plate boundaries. Using GPlate, we provide a statistical analysis of present-day obliquity along plate boundaries. Within this framework, by comparing natural examples and geological models, we discuss deformation patterns and kinematics recorded along oblique plate boundaries.

  10. Angular shear plate

    Science.gov (United States)

    Ruda, Mitchell C [Tucson, AZ; Greynolds, Alan W [Tucson, AZ; Stuhlinger, Tilman W [Tucson, AZ

    2009-07-14

    One or more disc-shaped angular shear plates each include a region thereon having a thickness that varies with a nonlinear function. For the case of two such shear plates, they are positioned in a facing relationship and rotated relative to each other. Light passing through the variable thickness regions in the angular plates is refracted. By properly timing the relative rotation of the plates and by the use of an appropriate polynomial function for the thickness of the shear plate, light passing therethrough can be focused at variable positions.

  11. Motion of Confined Particles

    CERN Document Server

    Miller, David E

    2016-01-01

    We carry out numerical evaluations of the motion of classical particles in Minkowski Space $\\mathbb{M}^{4}$ which are confined to the inside of a bag. In particular, we analyze the structure of the paths evolving from the breaking of the dilatation symmetry, the conformal symmetry and the combination of both together. The confining forces arise directly from the corresponding nonconserved currents. We demonstrate in our evaluations that these particles under certain initial conditions move toward the interior of the bag.

  12. An investigation of the effects of wind-induced inclination on floating wind turbine dynamics: heave plate excursion

    OpenAIRE

    Antonutti, Raffaello; Peyrard, Christophe; Johanning, Lars; Ingram, David; Incecik, Atilla

    2014-01-01

    A current trend in offshore wind is the quest for exploitation of ever deeper water sites. At depths between 50 m and 100 m a promising substructure is the column-stabilised semi-submersible floating type. This solution is currently being tested at full scale at the WindFloat and Fukushima Forward demonstrator sites in Portugal and Japan respectively. The semi-sub design class frequently adopts passive motion control devices based on the water entrapment principle, such as heave plates, tanks...

  13. Abrupt plate accelerations shape rifted continental margins

    Science.gov (United States)

    Brune, Sascha; Williams, Simon E.; Butterworth, Nathaniel P.; Müller, R. Dietmar

    2016-08-01

    Rifted margins are formed by persistent stretching of continental lithosphere until breakup is achieved. It is well known that strain-rate-dependent processes control rift evolution, yet quantified extension histories of Earth’s major passive margins have become available only recently. Here we investigate rift kinematics globally by applying a new geotectonic analysis technique to revised global plate reconstructions. We find that rifted margins feature an initial, slow rift phase (less than ten millimetres per year, full rate) and that an abrupt increase of plate divergence introduces a fast rift phase. Plate acceleration takes place before continental rupture and considerable margin area is created during each phase. We reproduce the rapid transition from slow to fast extension using analytical and numerical modelling with constant force boundary conditions. The extension models suggest that the two-phase velocity behaviour is caused by a rift-intrinsic strength-velocity feedback, which can be robustly inferred for diverse lithosphere configurations and rheologies. Our results explain differences between proximal and distal margin areas and demonstrate that abrupt plate acceleration during continental rifting is controlled by the nonlinear decay of the resistive rift strength force. This mechanism provides an explanation for several previously unexplained rapid absolute plate motion changes, offering new insights into the balance of plate driving forces through time.

  14. Abrupt plate accelerations shape rifted continental margins.

    Science.gov (United States)

    Brune, Sascha; Williams, Simon E; Butterworth, Nathaniel P; Müller, R Dietmar

    2016-08-11

    Rifted margins are formed by persistent stretching of continental lithosphere until breakup is achieved. It is well known that strain-rate-dependent processes control rift evolution, yet quantified extension histories of Earth's major passive margins have become available only recently. Here we investigate rift kinematics globally by applying a new geotectonic analysis technique to revised global plate reconstructions. We find that rifted margins feature an initial, slow rift phase (less than ten millimetres per year, full rate) and that an abrupt increase of plate divergence introduces a fast rift phase. Plate acceleration takes place before continental rupture and considerable margin area is created during each phase. We reproduce the rapid transition from slow to fast extension using analytical and numerical modelling with constant force boundary conditions. The extension models suggest that the two-phase velocity behaviour is caused by a rift-intrinsic strength--velocity feedback, which can be robustly inferred for diverse lithosphere configurations and rheologies. Our results explain differences between proximal and distal margin areas and demonstrate that abrupt plate acceleration during continental rifting is controlled by the nonlinear decay of the resistive rift strength force. This mechanism provides an explanation for several previously unexplained rapid absolute plate motion changes, offering new insights into the balance of plate driving forces through time.

  15. Thermodynamic energy exchange in a moving plate capacitor.

    Science.gov (United States)

    Davis, B. R.; Abbott, D.; Parrondo, J. M. R.

    2001-09-01

    In this paper we describe an apparent paradox concerning a moving plate capacitor driven by thermal noise from a resistor. The plates are attracted together, but a demon restores the plates of the capacitor to their original position when the voltage across the capacitor is small-hence only small forces are present for the demon to work against. The demon has to work harder than this to avoid the situation of perpetual motion, but the open question is how? This is unsolved, however we explore the concept of a moving plate capacitor by examining the case where it is still excited by thermal noise, but where the restoring force on the capacitor plates is provided by a simple spring rather than some unknown demon. We display simulation results with interesting behavior, particularly where the capacitor plates collide with each other. (c) 2001 American Institute of Physics.

  16. Thermodynamic energy exchange in a moving plate capacitor

    Science.gov (United States)

    Davis, B. R.; Abbott, D.; Parrondo, J. M. R.

    2001-09-01

    In this paper we describe an apparent paradox concerning a moving plate capacitor driven by thermal noise from a resistor. The plates are attracted together, but a demon restores the plates of the capacitor to their original position when the voltage across the capacitor is small—hence only small forces are present for the demon to work against. The demon has to work harder than this to avoid the situation of perpetual motion, but the open question is how? This is unsolved, however we explore the concept of a moving plate capacitor by examining the case where it is still excited by thermal noise, but where the restoring force on the capacitor plates is provided by a simple spring rather than some unknown demon. We display simulation results with interesting behavior, particularly where the capacitor plates collide with each other.

  17. Three-dimensional motion stability of upper thoratic anterior titanium plate fixed system: An in vitro biomechanical study%体外生物力学评价上胸椎前路钛板内固定装置的三维运动稳定性

    Institute of Scientific and Technical Information of China (English)

    罗巨利; 詹新立; 肖增明; 贺聚良; 刘会江; 赵卫东

    2011-01-01

    BACKGROUND: There are few reports about in vitro biomechanical studies of anterior cervical locking plate for upper thoracic reconstruction .OBJECTIVE: To evaluate the biomechanical characters of self-designed upper thoratic anterior titanium plate fixed system.METHODS: Intact C7-T6 specimens from 15 fresh corpses were randomly divided into three groups: group B with upper thoracic anterior titanium plate fixation (UTAPF), group C with prespred anterior cervical plate fixation (ACPF), group D with imprespred ACPF. Range of motion (ROM) was tested for the natural intact specimens. Measurement of three-dimensional stability was performed in flexion, extension and lateral bending and rotation state in groups B, C, D after fixation.RESULTS AND CONCLUSION: ROM of the natural intact specimens in the three groups had no significant difference (P > 0.05).The stability of flexion arranged as follows: B>D>C>intact specimens (A). Significant difference between B and A was found (P=0.012). The stability of extension arranged as follows: B>C>A>D, but there was no significant difference among different groups. The stability of rotation arranged B>C>A>D. Between groups no significant difference was found in the rotation condition.The order of stabilities under the lateral bending was A>B>C>D. There were significant differences between A and C as well as between A and D (P=0.005, P=0.002). The findings indicate that the upper thoracic anterior titanium plate has a better biomechanical stability than cervical plate. If cervical anterior plate was applied to upper thoratic spine, plate should be prespred according to kyphosis of the upper thoratic spine.%背景:国内外少见颈前路带锁钢板重建上胸椎的体外生物力学报道.目的:从生物力学角度评价自行研制的上胸椎前路钛板内固定装置.方法:15具成人尸体上胸椎标本分成3组,即上胸椎前路钛板内固定组(B),颈前路钛板预弯内固定组(C),颈前路

  18. Numerical modelling of instantaneous plate tectonics

    Science.gov (United States)

    Minster, J. B.; Haines, E.; Jordan, T. H.; Molnar, P.

    1974-01-01

    Assuming lithospheric plates to be rigid, 68 spreading rates, 62 fracture zones trends, and 106 earthquake slip vectors are systematically inverted to obtain a self-consistent model of instantaneous relative motions for eleven major plates. The inverse problem is linearized and solved iteratively by a maximum-likelihood procedure. Because the uncertainties in the data are small, Gaussian statistics are shown to be adequate. The use of a linear theory permits (1) the calculation of the uncertainties in the various angular velocity vectors caused by uncertainties in the data, and (2) quantitative examination of the distribution of information within the data set. The existence of a self-consistent model satisfying all the data is strong justification of the rigid plate assumption. Slow movement between North and South America is shown to be resolvable.

  19. Flow of nanofluid past a Riga plate

    Science.gov (United States)

    Ahmad, Adeel; Asghar, Saleem; Afzal, Sumaira

    2016-03-01

    This paper studies the mixed convection boundary layer flow of a nanofluid past a vertical Riga plate in the presence of strong suction. The mathematical model incorporates the Brownian motion and thermophoresis effects due to nanofluid and the Grinberg-term for the wall parallel Lorentz force due to Riga plate. The analytical solution of the problem is presented using the perturbation method for small Brownian and thermophoresis diffusion parameters. The numerical solution is also presented to ensure the reliability of the asymptotic method. The comparison of the two solutions shows an excellent agreement. The correlation expressions for skin friction, Nusselt number and Sherwood number are developed by performing linear regression on the obtained numerical data. The effects of nanofluid and the Lorentz force due to Riga plate, on the skin friction are discussed.

  20. Motion Simulator

    Science.gov (United States)

    1993-01-01

    MOOG, Inc. supplies hydraulic actuators for the Space Shuttle. When MOOG learned NASA was interested in electric actuators for possible future use, the company designed them with assistance from Marshall Space Flight Center. They also decided to pursue the system's commercial potential. This led to partnership with InterActive Simulation, Inc. for production of cabin flight simulators for museums, expositions, etc. The resulting products, the Magic Motion Simulator 30 Series, are the first electric powered simulators. Movements are computer-guided, including free fall to heighten the sense of moving through space. A projection system provides visual effects, and the 11 speakers of a digital laser based sound system add to the realism. The electric actuators are easier to install, have lower operating costs, noise, heat and staff requirements. The U.S. Space & Rocket Center and several other organizations have purchased the simulators.

  1. Ocean Basin Evolution and Global-Scale Plate Reorganization Events Since Pangea Breakup

    Science.gov (United States)

    Müller, R. Dietmar; Seton, Maria; Zahirovic, Sabin; Williams, Simon E.; Matthews, Kara J.; Wright, Nicky M.; Shephard, Grace E.; Maloney, Kayla T.; Barnett-Moore, Nicholas; Hosseinpour, Maral; Bower, Dan J.; Cannon, John

    2016-06-01

    We present a revised global plate motion model with continuously closing plate boundaries ranging from the Triassic at 230 Ma to the present day, assess differences among alternative absolute plate motion models, and review global tectonic events. Relatively high mean absolute plate motion rates of approximately 9-10 cm yr-1 between 140 and 120 Ma may be related to transient plate motion accelerations driven by the successive emplacement of a sequence of large igneous provinces during that time. An event at ˜100 Ma is most clearly expressed in the Indian Ocean and may reflect the initiation of Andean-style subduction along southern continental Eurasia, whereas an acceleration at ˜80 Ma of mean rates from 6 to 8 cm yr-1 reflects the initial northward acceleration of India and simultaneous speedups of plates in the Pacific. An event at ˜50 Ma expressed in relative, and some absolute, plate motion changes around the globe and in a reduction of global mean plate speeds from about 6 to 4-5 cm yr-1 indicates that an increase in collisional forces (such as the India-Eurasia collision) and ridge subduction events in the Pacific (such as the Izanagi-Pacific Ridge) play a significant role in modulating plate velocities.

  2. Flow structures generated by elongated plates settling in a water column

    DEFF Research Database (Denmark)

    Sørensen, Henrik; Jensen, Anna Lyhne; Hærvig, Jakob

    angle of 15° in a 0.60 m x 0.30 m  0.35 m (LBH) glass container filled with water. Continuous Particle Image Velocimetry is used to analyse both the velocity field of the continuous phase and the motion of the plates. The experiments show a well-defined oscillating motion of the plate. A stall occurs...... of the dimensionless moment of inertia and Reynolds number was investigated. The objective of the present work is to collect and present experimental data about the flow structures generated by the settling of elongated plates in a water column. The experiments are carried out by releasing the plates at an initial...... each time the plate changes horizontal direction of motion. The results show a flow building up when the plate accelerates and a vortex rolling off in each turn....

  3. A Study of the Effect of Gold Thickness Distribution in the Jet Plating Process to Optimize Gold Usage and Plating Voltage Using Design of Experiments

    Directory of Open Access Journals (Sweden)

    Aramphongphun Chuckaphun

    2016-01-01

    Full Text Available A gold plating process in the electronics industry can be classified as (i all surface plating or (ii selective plating. Selective plating is more widely used than all surface plating because it can save more gold used in the plating process and takes less plating time. In this research, the selective plating process called jet plating was studied. Factors that possibly affected the gold usage and plating voltage were also studied to reduce the production cost. These factors included (a plating temperature, (b crystal (inhibitor amount, (c distance between workpiece and anode, (d plating current and (e plating speed. A two-level Full Factorial design with center points was first performed to screen the factors. A Central Composite Design (CCD was then employed to optimize the factors in jet plating. The amount of gold usage should be reduced to 0.366 g / 10,000 pieces, the plating speed should be increased to 4 m/min and the plating voltage should not exceed 8.0 V. According to the analysis, the optimal settings should be as follows: the plating temperature at 55.5 deg C, the crystal amount at 90%, the distance at 0.5 mm, the plating current at 2.8 A, and the plating speed at 4.5 m/min. This optimal setting led to gold usage of 0.350 g / 10,000 pieces and a plating voltage of 7.16 V. Confirmation runs of 30 experiments at the optimal conditions were then performed. It was found that the gold usage and the plating voltage of the confirmation runs were not different from the optimized gold usage and plating voltage. The optimal condition was then applied in production, which could reduce the gold usage by 4.5% and increase the plating speed by 12.5% while the plating voltage did not exceed the limit.

  4. The San Andreas fault experiment. [gross tectonic plates relative velocity

    Science.gov (United States)

    Smith, D. E.; Vonbun, F. O.

    1973-01-01

    A plan was developed during 1971 to determine gross tectonic plate motions along the San Andreas Fault System in California. Knowledge of the gross motion along the total fault system is an essential component in the construction of realistic deformation models of fault regions. Such mathematical models will be used in the future for studies which will eventually lead to prediction of major earthquakes. The main purpose of the experiment described is the determination of the relative velocity of the North American and the Pacific Plates. This motion being so extremely small, cannot be measured directly but can be deduced from distance measurements between points on opposite sites of the plate boundary taken over a number of years.

  5. On the rotation and pitching of flat plates

    Science.gov (United States)

    Jin, Yaqing; Ji, Sheng; Chamorro, Leonardo P.

    2016-11-01

    Wind tunnel experiments were performed to characterize the flow-induced rotation and pitching of various flat plates as a function of the thickness ratio, the location of the axis of rotation and turbulence levels. High-resolution telemetry, laser tachometer, and hotwire were used to get time series of the plates motions and the signature of the wake flow at a specific location. Results show that a minor axis offset can induce high-order modes in the plate rotation under low turbulence due to torque unbalance. The spectral decomposition of the flow velocity in the plate wake reveals the existence of a dominating high-frequency mode that corresponds to a static-like vortex shedding occurring at the maximum plate pitch, where the characteristic length scale is the projected width at maximum pitch. The plate thickness ratio shows inverse relation with the angular velocity. A simple model is derived to explain the linear relation between pitching frequency and wind speed. The spectra of the plate rotation show nonlinear relation with the incoming turbulence, and the dominating role of the generated vortices in the plate motions.

  6. Generalized Fibonacci zone plates

    CERN Document Server

    Ke, Jie; Zhu, Jianqiang

    2015-01-01

    We propose a family of zone plates which are produced by the generalized Fibonacci sequences and their axial focusing properties are analyzed in detail. Compared with traditional Fresnel zone plates, the generalized Fibonacci zone plates present two axial foci with equal intensity. Besides, we propose an approach to adjust the axial locations of the two foci by means of different optical path difference, and further give the deterministic ratio of the two focal distances which attributes to their own generalized Fibonacci sequences. The generalized Fibonacci zone plates may allow for new applications in micro and nanophotonics.

  7. Mantle flow geometry from ridge to trench beneath the Gorda-Juan de Fuca plate system

    Science.gov (United States)

    Martin-Short, Robert; Allen, Richard M.; Bastow, Ian D.; Totten, Eoghan; Richards, Mark A.

    2015-12-01

    Tectonic plates are underlain by a low-viscosity mantle layer, the asthenosphere. Asthenospheric flow may be induced by the overriding plate or by deeper mantle convection. Shear strain due to this flow can be inferred using the directional dependence of seismic wave speeds--seismic anisotropy. However, isolation of asthenospheric signals is challenging; most seismometers are located on continents, whose complex structure influences the seismic waves en route to the surface. The Cascadia Initiative, an offshore seismometer deployment in the US Pacific Northwest, offers the opportunity to analyse seismic data recorded on simpler oceanic lithosphere. Here we use measurements of seismic anisotropy across the Juan de Fuca and Gorda plates to reconstruct patterns of asthenospheric mantle shear flow from the Juan de Fuca mid-ocean ridge to the Cascadia subduction zone trench. We find that the direction of fastest seismic wave motion rotates with increasing distance from the mid-ocean ridge to become aligned with the direction of motion of the Juan de Fuca Plate, implying that this plate influences mantle flow. In contrast, asthenospheric mantle flow beneath the Gorda Plate does not align with Gorda Plate motion and instead aligns with the neighbouring Pacific Plate motion. These results show that asthenospheric flow beneath the small, slow-moving Gorda Plate is controlled largely by advection due to the much larger, faster-moving Pacific Plate.

  8. Auditory Motion Elicits a Visual Motion Aftereffect

    Directory of Open Access Journals (Sweden)

    Christopher C. Berger

    2016-12-01

    Full Text Available The visual motion aftereffect is a visual illusion in which exposure to continuous motion in one direction leads to a subsequent illusion of visual motion in the opposite direction. Previous findings have been mixed with regard to whether this visual illusion can be induced cross-modally by auditory stimuli. Based on research on multisensory perception demonstrating the profound influence auditory perception can have on the interpretation and perceived motion of visual stimuli, we hypothesized that exposure to auditory stimuli with strong directional motion cues should induce a visual motion aftereffect. Here, we demonstrate that horizontally moving auditory stimuli induced a significant visual motion aftereffect—an effect that was driven primarily by a change in visual motion perception following exposure to leftward moving auditory stimuli. This finding is consistent with the notion that visual and auditory motion perception rely on at least partially overlapping neural substrates.

  9. Finite element analysis of distal femoral locking plate and minimally invasive internal fixation system in different motion states%股骨远端锁定微创内固定系统不同运动状态下的有限元分析

    Institute of Scientific and Technical Information of China (English)

    郝廷; 王兴国; 李筱贺

    2016-01-01

    BACKGROUND:Traditional distal femoral fixation plate screw breakage is relatively common. Designing good anatomical and attached fixation system is the key for clinical application. OBJECTIVE:To perform finite element analysis in two states of motion of the minimal y invasive distal femoral fixation system, compare stress distribution of different parts in the same fixed way, different fixed methods and the same fixed parts of different motion states. METHODS:Imaging data of a 34-year-old male patient weighing 68 kg with 33-C1 type fracture of distal femur were selected. CT data were input into Mimics 16.0 for reconstruction. PRO-E software was used to establish minimal y invasive internal fixation system with distal femoral locking plate. Data were introduced into reconstructed models of distal femur fracture in Mimics for grid division. Data were introduced into Ansys products 11.0 to construct finite element model, fix the surface of distal femur, and loaded 340 N on greater trochanter of femur. Stress distribution of each plate, screw hole and screw tail was analyzed in each group. Stress at the same region was compared in flexion and extension movement states. RESULTS AND CONCLUSION:(1) Finite element models of anatomic locking plate for distal femur fracture fixation were successful y established, total y 43 536 units, 41 256 nodes. (2) With the steel segment gradual y down (S1-S5), the stress gradual y increased. A1-A5 with the increase in the number of screws, the stress gradual y increased, but A6 suddenly decreased. (3) According to the cloud atlas of stress, these were wel distributed except A1. From distal end to extremity of screw, the stress of screws increased. Among corresponding segments, significant differences in stress around the nail holes and steel segment stress were detected. Moreover, the steel stress was greater than the stress of corresponding segment of screw hole. (4) Results suggest that using anatomical locking plate and minimal y

  10. Is plate tectonis withstanding the test of time?

    Directory of Open Access Journals (Sweden)

    O. Shields

    1997-06-01

    Full Text Available Since the theory of plate tectonics was first proposed thirty years ago, some problems have arisen in its practical application. These call into question its fundamental assumptions of horizontal plate motion, hotspot fixity, true polar wander, Panthalassa, and the Earth’s constant size while leaving seafloor spreading and subduction intact. A rapidity expanding earth solves these problems and privides an alternative viewpoint worth reconsidering.

  11. Tectonic Plate Parameters Estimated in the International Terrestrial Reference Frame ITRF2008 Based on SLR Stations

    Directory of Open Access Journals (Sweden)

    Kraszewska Katarzyna

    2016-10-01

    Full Text Available This paper concerns an analysis of the accuracy of estimated parameters Ω(Φ, Λ, ω which define the tectonic plate motions. The study is based on the velocities of station positions published by ITRF2008 for Satellite Laser Ranging (SLR technique. The Eurasian, African, North American and Australian plates were used in the analysis. Influence of the number and location of stations on the plate surface on estimation accuracy of the tectonic plate motion parameters was discussed. The results were compared with the APKIM 2005 IGN model. In general, a remarkable concurrence agreement between our solutions and the APKIM 2005 model was found.

  12. Microchannel Plate Imaging Detectors for the Ultraviolet

    Science.gov (United States)

    Siegmund, O. H. W.; Gummin, M. A.; Stock, J.; Marsh, D.

    1992-01-01

    There has been significant progress over the last few years in the development of technologies for microchannel plate imaging detectors in the Ultraviolet (UV). Areas where significant developments have occurred include enhancements of quantum detection efficiency through improved photocathodes, advances in microchannel plate performance characteristics, and development of high performance image readout techniques. The current developments in these areas are summarized, with their applications in astrophysical instrumentation.

  13. Collective motion

    Science.gov (United States)

    Vicsek, Tamás; Zafeiris, Anna

    2012-08-01

    We review the observations and the basic laws describing the essential aspects of collective motion - being one of the most common and spectacular manifestation of coordinated behavior. Our aim is to provide a balanced discussion of the various facets of this highly multidisciplinary field, including experiments, mathematical methods and models for simulations, so that readers with a variety of background could get both the basics and a broader, more detailed picture of the field. The observations we report on include systems consisting of units ranging from macromolecules through metallic rods and robots to groups of animals and people. Some emphasis is put on models that are simple and realistic enough to reproduce the numerous related observations and are useful for developing concepts for a better understanding of the complexity of systems consisting of many simultaneously moving entities. As such, these models allow the establishing of a few fundamental principles of flocking. In particular, it is demonstrated, that in spite of considerable differences, a number of deep analogies exist between equilibrium statistical physics systems and those made of self-propelled (in most cases living) units. In both cases only a few well defined macroscopic/collective states occur and the transitions between these states follow a similar scenario, involving discontinuity and algebraic divergences.

  14. Comment on "Similarity analysis in magnetohydrodynamics: effects of Hall and ion-slip currents on free convection flow and mass transfer of a gas past a semi-infinite vertical plate," A.A. Megahed, S.R. Komy, A.A. Afify

    CERN Document Server

    Pantokratoras, Asterios

    2007-01-01

    Comment on Similarity analysis in magnetohydrodynamics:effects of Hall and ion-slip currents on free convection flow and mass transfer of a gas past a semi-infinite vertical plate, A.A. Megahed, S.R. Komy, A.A. Afify [Acta Mechanica 151, 185-194 (2001)] In the above paper is investigated the boundary layer flow of an electrically conducting fluid over a vertical, stationary plate placed in a calm fluid. The effects of Hall and ion-slip currents are taken into account. The boundary layer equations are transformed into ordinary ones using a scaling group of transformations and subsequently are solved numerically. However, there are two fundamental errors in the above paper which are presented below.

  15. Blue Willow Story Plates

    Science.gov (United States)

    Fontes, Kris

    2009-01-01

    In the December 1997 issue of "SchoolArts" is a lesson titled "Blue Willow Story Plates" by Susan Striker. In this article, the author shares how she used this lesson with her middle-school students many times over the years. Here, she describes a Blue Willow plate painting project that her students made.

  16. Create Your Plate

    Medline Plus

    Full Text Available ... In Memory In Honor Become a Member En Español Type 1 Type 2 About Us Online Community ... Page Text Size: A A A Listen En Español Create Your Plate Create Your Plate is a ...

  17. Create Your Plate

    Medline Plus

    Full Text Available ... Diabetes Meal Plans Create Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart-Healthy Foods Holiday Meal Planning ... Planning Meals Diabetes Meal Plans and a Healthy Diet Create Your Plate Meal Planning for Vegetarian Diets ...

  18. The role of the heating mode of the mantle in intermittent reorganization of the plate velocity field

    Science.gov (United States)

    Lowman, Julian P.; King, Scott D.; Gable, Carl W.

    2003-02-01

    The geological record indicates that stages of relatively steady plate motion have been punctuated by comparatively brief periods in which plate velocities have reorganized. The distribution of buoyancy sources in the mantle has generally been regarded as evolving too slowly to explain these rapid transitions in plate velocity. We investigate the feedback between mantle convection and plate velocity using 2-D and 3-D mantle convection models that incorporate mobile dynamic plates. We focus on the influence of internal heating in the mantle and consider the effect of mantle viscosity stratification and different plate geometries on the plate velocity time dependence. As either the Rayleigh number or the internal heating rate is increased to magnitudes approaching mantle values, the record of the plate motion from our calculations becomes characterized by intermittent changes in direction. This behaviour is a result of the influence of plates on heat loss from the inherently unsteady, internally heated convecting system. Plate motion instills a pattern of organization on the underlying convection that reflects the plate geometry and results in the formation of sheet-like downwelling structures at convergent plate boundaries in both 2-D and 3-D calculations (in contrast, upwellings in 3-D models are not sheet-like). The role of the sheet-like downwellings is critical in the observed episodic reorganization of the plate velocities. Warm material below the plates is entrained by plate motion into regions enveloping the downwelling sheets. During periods of fairly steady plate motion, buoyancy associated with the build-up of heat around the downwelling sheets leads to the creation of an unstable convection pattern. This build-up of heat is dramatic in calculations with mantle-like internal heating rates and resists continued long-term plate motion towards mature downwellings. When there are limitations on the degree of freedom of the direction of plate movement, such as

  19. Motion control report

    CERN Document Server

    2013-01-01

    Please note this is a short discount publication. In today's manufacturing environment, Motion Control plays a major role in virtually every project.The Motion Control Report provides a comprehensive overview of the technology of Motion Control:* Design Considerations* Technologies* Methods to Control Motion* Examples of Motion Control in Systems* A Detailed Vendors List

  20. Flow structure on a rotating plate

    Energy Technology Data Exchange (ETDEWEB)

    Ozen, C.A.; Rockwell, D. [Lehigh University, Department of Mechanical Engineering and Mechanics, Bethlehem, PA (United States)

    2012-01-15

    The flow structure on a rotating plate of low aspect ratio is characterized well after the onset of motion, such that transient effects are not significant, and only centripetal and Coriolis accelerations are present. Patterns of vorticity, velocity contours, and streamline topology are determined via quantitative imaging, in order to characterize the leading-edge vortex in relation to the overall flow structure. A stable leading-edge vortex is maintained over effective angles of attack from 30 to 75 , and at each angle of attack, its sectional structure at midspan is relatively insensitive to Reynolds number over the range from 3,600 to 14,500. The streamline topology, vorticity distribution, and circulation of the leading-edge vortex are determined as a function of angle of attack, and related to the velocity field oriented toward, and extending along, the leeward surface of the plate. The structure of the leading-edge vortex is classified into basic regimes along the span of the plate. Images of these regimes are complemented by patterns on crossflow planes, which indicate the influence of root and tip swirl, and spanwise flow along the leeward surface of the plate. Comparison with the equivalent of the purely translating plate, which does not induce the foregoing flow structure, further clarifies the effects of rotation. (orig.)

  1. 波流作用下深水网箱受力及运动变形的数值模拟%Numerical simulation of forces and motion deformation of deep-water net cages in waves and currents

    Institute of Scientific and Technical Information of China (English)

    黄小华; 郭根喜; 胡昱; 陶启友; 张小明

    2011-01-01

    This study is aimed to discuss the effects of waves combined with currents on forces and motion deformation of deep-water net cages, and provides a strong reference to risk assessment for net-cage aquaculture with severe marine conditions. The set value of wave and current elements were as follows: wave heights H=4-6 m,wave periods T=6.0-8.6s, current velocities U=0.3-0.9 m/s. With a numerical model previously validated by physical model tests, the mooring line forces, the wave-current forces, the volume reduction rate and the floating-collar pitches of the deep-water net cage were calculated. The simulated results indicated that the mooring line force, the wave-current force and the volume reduction rate were all in direct proportion to wave height as well as current velocity, but less related to wave period. Furthermore, the wave-current force on the cage was approximately equal to the sum of force on each mooring line on wave-side. The volume reduction rate reached 47%-56% for the cage caused by the conditions of wave height of 4-6 m and current velocity of 0.75m/s, which showed serious cage deformation. Therefore, we concluded that farming sites should not be placed in sea areas where current speed exceeded 0.75 m/s. The calculated results also showed that the influence of wave period on volume reduction rate was slight, while significant on the floating-collar pitch. The floating-collar pitch would decrease as wave period increasing at constant wave height and current velocity.%基于已建立的浮架和网衣数学模型,对不同波况和流速共同作用条件下HDPE深水网箱所受的锚绳力、波流力、容积损失率以及浮架倾角进行数值计算,设计的波流要素值为:波高H=4~6 m,周期T=6.0~8.6 s,流速U=0.3~0.9 m/s.结果表明,网箱锚绳受力、波流力和容积损失率均与波高和流速成正比,与周期的关系不明显,且网箱系统所受的波流力约为网箱迎浪侧两根锚

  2. Simulation of Arc Motion in Air Switching Devices Taking Ferromagnetic Material into Accout

    Institute of Scientific and Technical Information of China (English)

    LI Xingwen; TUSONGJIANG Kari; CHEN Degui; SUN Haitao; XIE Ensheng

    2009-01-01

    FLUENT and ANSYS codes axe used to solve the magnethydrodynamics (MHD)equations and electromagnetic field equations, respectively. An interface code is developed to implement the bi-direction transfer of calculation data between FLUENT and ANSYS. Then a 2-D MHD arc model is built up with the consideration of the nonlinear ferromagnetic material.The arc shape, gas flow velocity and magnetic field distribution are presented at a current of 200 A. The influence of the number of splitter plates on arc motion is also analyzed.

  3. Plate tectonics in the late Paleozoic

    Directory of Open Access Journals (Sweden)

    Mathew Domeier

    2014-05-01

    Full Text Available As the chronicle of plate motions through time, paleogeography is fundamental to our understanding of plate tectonics and its role in shaping the geology of the present-day. To properly appreciate the history of tectonics—and its influence on the deep Earth and climate—it is imperative to seek an accurate and global model of paleogeography. However, owing to the incessant loss of oceanic lithosphere through subduction, the paleogeographic reconstruction of ‘full-plates’ (including oceanic lithosphere becomes increasingly challenging with age. Prior to 150 Ma ∼60% of the lithosphere is missing and reconstructions are developed without explicit regard for oceanic lithosphere or plate tectonic principles; in effect, reflecting the earlier mobilistic paradigm of continental drift. Although these ‘continental’ reconstructions have been immensely useful, the next-generation of mantle models requires global plate kinematic descriptions with full-plate reconstructions. Moreover, in disregarding (or only loosely applying plate tectonic rules, continental reconstructions fail to take advantage of a wealth of additional information in the form of practical constraints. Following a series of new developments, both in geodynamic theory and analytical tools, it is now feasible to construct full-plate models that lend themselves to testing by the wider Earth-science community. Such a model is presented here for the late Paleozoic (410–250 Ma together with a review of the underlying data. Although we expect this model to be particularly useful for numerical mantle modeling, we hope that it will also serve as a general framework for understanding late Paleozoic tectonics, one on which future improvements can be built and further tested.

  4. Plate tectonics in the late Paleozoic

    Institute of Scientific and Technical Information of China (English)

    Mathew Domeier; Trond H. Torsvik

    2014-01-01

    As the chronicle of plate motions through time, paleogeography is fundamental to our understanding of plate tectonics and its role in shaping the geology of the present-day. To properly appreciate the history of tectonicsdand its influence on the deep Earth and climatedit is imperative to seek an accurate and global model of paleogeography. However, owing to the incessant loss of oceanic lithosphere through subduction, the paleogeographic reconstruction of‘full-plates’ (including oceanic lithosphere) becomes increasingly challenging with age. Prior to 150 Ma w60% of the lithosphere is missing and re-constructions are developed without explicit regard for oceanic lithosphere or plate tectonic principles;in effect, reflecting the earlier mobilistic paradigm of continental drift. Although these ‘continental’ re-constructions have been immensely useful, the next-generation of mantle models requires global plate kinematic descriptions with full-plate reconstructions. Moreover, in disregarding (or only loosely applying) plate tectonic rules, continental reconstructions fail to take advantage of a wealth of additional information in the form of practical constraints. Following a series of new developments, both in geo-dynamic theory and analytical tools, it is now feasible to construct full-plate models that lend themselves to testing by the wider Earth-science community. Such a model is presented here for the late Paleozoic (410e250 Ma) together with a review of the underlying data. Although we expect this model to be particularly useful for numerical mantle modeling, we hope that it will also serve as a general framework for understanding late Paleozoic tectonics, one on which future improvements can be built and further tested.

  5. Plate boundaries and evolution of the Solomon Sea region

    Science.gov (United States)

    Honza, E.; Davies, H. L.; Keene, J. B.; Tiffin, D. L.

    1987-09-01

    The Solomon Sea Plate was widely developed during late Oligocene, separating the proto-West Melanesian Arc from the proto-Trobriand Arc. Spreading in the Bismarck Sea and in the Woodlark Basin resulted from interaction between the Pacific and Australian Plates, specifically from the collision of the proto-West Melanesian Arc with north New Guinea, which occurred after arc reversal. This model explains the extensive Miocene, Pliocene, and Quaternary volcanism of the Papua New Guinea mainland as it related to southward subduction of the Trobriand Trough. Our interpreted plate motions are concordant with the geological evidence onshore and also with complex tectonic features in the Solomon Sea Basin Region.

  6. Present-day spreading motion of the mid-Atlantic ridge

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Over a long period of time, the spreading rate of the mid-Atlantic ridge has been ascertained by the geological age of the magnetic stripe laid out oneither side of the mid-ocean ridge in conjunction with the annals of the magnetic reversal history. Is the mid-Atlantic ridge still spreading today? How fast is it moving or are there any changes? All these questions remain unsolved. Basedon the newest ITRF2000 velocity field published by the International Earth Rotation Service (IERS), the contemporary global plate motion model ITRF2000VEL is constructed, independent of any plate model hypothesis. Solutions for relative Euler's vectors of plate pairs as North America-Eurasia, North America- Africa andSouth America-Africa are obtained, implying current spreading rates of the mid-Atlantic ridge. Comparing them with results from the NNR-NUVEL1A model displays the present-day motion characteristics of the mid-Atlantic ridge that the mid-ridge of the South Atlantic, whose spreading is slowing down, spreads faster than the North Atlantic, whose spreading is speeding up.

  7. CFD Simulations of Oscillating Flow around Solid and Perforated Plates

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Damping plates have been used for truss spars in gulf of Mexico to reduce the heave motions. The plates are usually perforated with holes for the passage of marine risers, but the effects of the perforation have not been examined thoroughly. In the present study, a computational fluid dynamics investigation into the hydrodynamic forces is carried out by using FLUENT, which is on two-dimensional perforated plates with varying degrees of perforation in oscillating flow under small Keulegan-Carpenter (KC) number. The numerical results of the hydrodynamic coefficients are presented. The effects of both the perforation ratio (PR) and KC number on the hydrodynamic coefficients of the plates are discussed. Some results of the simulated flow patterns around the plates were also given and discussed.

  8. Closed-form solution for free vibration of piezoelectric coupled annular plates using Levinson plate theory

    Science.gov (United States)

    Hosseini Hashemi, Sh.; Es'haghi, M.; Karimi, M.

    2010-04-01

    Free vibration analysis of annular moderately thick plates integrated with piezoelectric layers is investigated in this study for different combinations of soft simply supported, hard simply supported and clamped boundary conditions at the inner and outer edges of the annular plate on the basis of the Levinson plate theory (LPT). The distribution of electric potential along the thickness direction in the piezoelectric layer is assumed as a sinusoidal function so that the Maxwell static electricity equation is approximately satisfied. The differential equations of motion are solved analytically for various boundary conditions of the plate. In this study the closed-form solution for characteristic equations, displacement components of the plate and electric potential are derived for the first time in the literature. To demonstrate the accuracy of the present solution, comparison studies is first carried out with the available data in the literature and then natural frequencies of the piezoelectric coupled annular plate are presented for different thickness-radius ratios, inner-outer radius ratios, thickness of piezoelectric, material of piezoelectric and boundary conditions. Present analytical model provides design reference for piezoelectric material application, such as sensors, actuators and ultrasonic motors.

  9. Pixelated neutron image plates

    Science.gov (United States)

    Schlapp, M.; Conrad, H.; von Seggern, H.

    2004-09-01

    Neutron image plates (NIPs) have found widespread application as neutron detectors for single-crystal and powder diffraction, small-angle scattering and tomography. After neutron exposure, the image plate can be read out by scanning with a laser. Commercially available NIPs consist of a powder mixture of BaFBr : Eu2+ and Gd2O3 dispersed in a polymer matrix and supported by a flexible polymer sheet. Since BaFBr : Eu2+ is an excellent x-ray storage phosphor, these NIPs are particularly sensitive to ggr-radiation, which is always present as a background radiation in neutron experiments. In this work we present results on NIPs consisting of KCl : Eu2+ and LiF that were fabricated into ceramic image plates in which the alkali halides act as a self-supporting matrix without the necessity for using a polymeric binder. An advantage of this type of NIP is the significantly reduced ggr-sensitivity. However, the much lower neutron absorption cross section of LiF compared with Gd2O3 demands a thicker image plate for obtaining comparable neutron absorption. The greater thickness of the NIP inevitably leads to a loss in spatial resolution of the image plate. However, this reduction in resolution can be restricted by a novel image plate concept in which a ceramic structure with square cells (referred to as a 'honeycomb') is embedded in the NIP, resulting in a pixelated image plate. In such a NIP the read-out light is confined to the particular illuminated pixel, decoupling the spatial resolution from the optical properties of the image plate material and morphology. In this work, a comparison of experimentally determined and simulated spatial resolutions of pixelated and unstructured image plates for a fixed read-out laser intensity is presented, as well as simulations of the properties of these NIPs at higher laser powers.

  10. Plate removal following orthognathic surgery.

    Science.gov (United States)

    Little, Mhairi; Langford, Richard Julian; Bhanji, Adam; Farr, David

    2015-11-01

    The objectives of this study are to determine the removal rates of orthognathic plates used during orthognathic surgery at James Cook University Hospital and describe the reasons for plate removal. 202 consecutive orthognathic cases were identified between July 2004 and July 2012. Demographics and procedure details were collected for these patients. Patients from this group who returned to theatre for plate removal between July 2004 and November 2012 were identified and their notes were analysed for data including reason for plate removal, age, smoking status, sex and time to plate removal. 3.2% of plates were removed with proportionally more plates removed from the mandible than the maxilla. 10.4% of patients required removal of one or more plate. Most plates were removed within the first post-operative year. The commonest reasons for plate removal were plate exposure and infection. The plate removal rates in our study are comparable to those seen in the literature.

  11. Anisotropic elastic plates

    CERN Document Server

    Hwu, Chyanbin

    2010-01-01

    As structural elements, anisotropic elastic plates find wide applications in modern technology. The plates here are considered to be subjected to not only in plane load but also transverse load. In other words, both plane and plate bending problems as well as the stretching-bending coupling problems are all explained in this book. In addition to the introduction of the theory of anisotropic elasticity, several important subjects have are discussed in this book such as interfaces, cracks, holes, inclusions, contact problems, piezoelectric materials, thermoelastic problems and boundary element a

  12. Plating in Top Agar

    OpenAIRE

    sprotocols

    2014-01-01

    1. Warm plates to room temperature before use. Cold plates causes the top agar to solidify irregularly. DO not warm plates to 37° as the top agar will take forever to solidify. - Prepare top agar as the appropriate liquid medium with 0.7% agar. Keeping 100 mL bottles is convenient. For phages, use λ top agar, which is less rich and yields bigger plaques. - Melt top agar in the microwave completely. Allow the agar to boil after liquification; incompletely melted agar looks liquid, but is...

  13. Corrosion test cell for bipolar plates

    Science.gov (United States)

    Weisbrod, Kirk R.

    2002-01-01

    A corrosion test cell for evaluating corrosion resistance in fuel cell bipolar plates is described. The cell has a transparent or translucent cell body having a pair of identical cell body members that seal against opposite sides of a bipolar plate. The cell includes an anode chamber and an cathode chamber, each on opposite sides of the plate. Each chamber contains a pair of mesh platinum current collectors and a catalyst layer pressed between current collectors and the plate. Each chamber is filled with an electrolyte solution that is replenished with fluid from a much larger electrolyte reservoir. The cell includes gas inlets to each chamber for hydrogen gas and air. As the gases flow into a chamber, they pass along the platinum mesh, through the catalyst layer, and to the bipolar plate. The gas exits the chamber through passageways that provide fluid communication between the anode and cathode chambers and the reservoir, and exits the test cell through an exit port in the reservoir. The flow of gas into the cell produces a constant flow of fresh electrolyte into each chamber. Openings in each cell body is member allow electrodes to enter the cell body and contact the electrolyte in the reservoir therein. During operation, while hydrogen gas is passed into one chamber and air into the other chamber, the cell resistance is measured, which is used to evaluate the corrosion properties of the bipolar plate.

  14. A pinned or free-floating plate on a thin viscous film. Part 1: A rigid plate

    CERN Document Server

    Trinh, Philippe H; Stone, Howard A

    2013-01-01

    We investigate a pinned or free-floating rigid plate lying on the free surface of a thin film of viscous fluid, which itself lies on top of a horizontal substrate that is moving to the right at a constant speed. Examples of situations in which this can occur include blade coating and the motion of a contact lens on the tear film of the eye after a blink. In contrast to the extensive previous work on fixed and clamped plates, in the present work we allow the plate to change both its position and orientation in response to the flow. Asymptotic and numerical analyses are described, and, in particular, we explain, in appropriate dimensionless terms, the role of the speed of the substrate, surface tension, viscosity and, in the case of a pinned plate, the prescribed pressure in the reservoir of fluid upstream of the plate, in determining the possible equilibrium configurations.

  15. Global Dynamic Numerical Simulations of Plate Tectonic Reorganizations

    Science.gov (United States)

    Morra, G.; Quevedo, L.; Butterworth, N.; Matthews, K. J.; Müller, D.

    2010-12-01

    We use a new numerical approach for global geodynamics to investigate the origin of present global plate motion and to identify the causes of the last two global tectonic reorganizations occurred about 50 and 100 million years ago (Ma) [1]. While the 50 Ma event is the most well-known global plate-mantle event, expressed by the bend in the Hawaiian-Emperor volcanic chain, a prominent plate reorganization at about 100 Ma, although presently little studied, is clearly indicated by a major bend in the fracture zones in the Indian Ocean and by a change in Pacific plate motion [2]. Our workflow involves turning plate reconstructions into surface meshes that are subsequently employed as initial conditions for global Boundary Element numerical models. The tectonic setting that anticipates the reorganizations is processed with the software GPlates, combining the 3D mesh of the paleo-plate morphology and the reconstruction of paleo-subducted slabs, elaborated from tectonic history [3]. All our models involve the entire planetary system, are fully dynamic, have free surface, are characterized by a spectacular computational speed due to the simultaneous use of the multi-pole algorithm and the Boundary Element formulation and are limited only by the use of sharp material property variations [4]. We employ this new tool to unravel the causes of plate tectonic reorganizations, producing and comparing global plate motion with the reconstructed ones. References: [1] Torsvik, T., Müller, R.D., Van der Voo, R., Steinberger, B., and Gaina, C., 2008, Global Plate Motion Frames: Toward a unified model: Reviews in Geophysics, VOL. 46, RG3004, 44 PP., 2008 [2] Wessel, P. and Kroenke, L.W. Pacific absolute plate motion since 145 Ma: An assessment of the fixed hot spot hypothesis. Journal of Geophysical Research, Vol 113, B06101, 2008 [3] L. Quevedo, G. Morra, R. D. Mueller. Parallel Fast Multipole Boundary Element Method for Crustal Dynamics, Proceeding 9th World Congress and 4th Asian

  16. Active NE-SW Compressional Strain Within the Arabian Plate

    Science.gov (United States)

    Floyd, M. A.; ArRajehi, A.; King, R. W.; McClusky, S.; Reilinger, R. E.; Douad, M.; Sholan, J.; Bou-Rabee, F.

    2012-12-01

    Motion of the Arabian plate with respect to Eurasia has been remarkably steady over more than 25 Myr as revealed by comparison of geodetic and plate tectonic reconstructions (e.g., McQuarrie et al., 2003, GRL; ArRajehi et al., 2010, Tectonics). While internal plate deformation is small in comparison to the rate of Arabia-Eurasia convergence, the improved resolution of GPS observations indicate ~ NE-SW compressional strain that appears to affect much of the plate south of latitude ~ 30°N. Seven ~ NE-SW oriented inter-station baselines all indicated shortening at rates in the range of 0.5-2 mm/yr, for the most part with 1-sigma velocity uncertainties < 0.4 mm/yr. Plate-scale strain rates exceed 2×10-9/yr. The spatial distribution of strain can not be resolved from the sparse available data, but strain appears to extend at least to Riyadh, KSA, ~ 600 km west of the Zagros Fold and Thrust Belt that forms the eastern, collisional boundary of the Arabian plate with Eurasia (Iran). Geodetic velocities in the plate tectonic reference frame for Arabia, derived from magnetic anomalies in the Red Sea (Chu and Gordon, 1998, GJI), show no significant E-W motion for GPS stations located along the Red Sea coast (i.e., geodetic and plate tectonic spreading rates across the Red Sea agree within their resolution), in contrast to sites in the plate interior and along the east side of the plate that indicate east-directed motions. In addition, NE-SW contraction is roughly normal to ~ N-S striking major structural folds in the sedimentary rocks within the Arabian Platform. These relationships suggest that geodetically observed contraction has characterized the plate for at least the past ~ 3 Myr. Broad-scale contraction of the Arabian plate seems intuitively reasonable given that the east and north sides of the plate are dominated by active continental collision (Zagros, E Turkey/Caucasus) while the west and south sides are bordered by mid-ocean ridge spreading (Red Sea and Gulf of

  17. Epeirogeny and plate tectonics

    Science.gov (United States)

    Menard, H. W.

    1975-01-01

    Vertical motions of the earth crust and their causes are considered in relation to epeirogenic phenomena. Factors discussed include: external loading and unloading; bending at subduction zones; internal density changes; and dynamic effects of mantle motion. The relationship between epeirogeny and drift is briefly reviewed along with oceanic epeirogeny.

  18. Create Your Plate

    Medline Plus

    Full Text Available ... blood glucose levels and lose weight. With this method, you fill your plate with more non-starchy ... but changes the portion sizes so you are getting larger portions of non-starchy vegetables and a ...

  19. Create Your Plate

    Medline Plus

    Full Text Available ... blood glucose levels and lose weight. With this method, you fill your plate with more non-starchy ... 4/Box) Taking the guesswork out of portion control has never been easier. It can be a ...

  20. Tectonic Plate Movement.

    Science.gov (United States)

    Landalf, Helen

    1998-01-01

    Presents an activity that employs movement to enable students to understand concepts related to plate tectonics. Argues that movement brings topics to life in a concrete way and helps children retain knowledge. (DDR)

  1. MyPlate

    Science.gov (United States)

    ... our stage of life, situations, preferences, access to food, culture, traditions, and the personal decisions we make over time. All your food and beverage choices count. MyPlate offers ideas and ...

  2. Create Your Plate

    Medline Plus

    Full Text Available ... blood glucose levels and lose weight. With this method, you fill your plate with more non-starchy ... you have an easy portion control solution that works. Last Reviewed: October 8, 2015 Last Edited: September ...

  3. Designing Assemblies Of Plates

    Science.gov (United States)

    Williams, F. W.; Kennedy, D.; Butler, R.; Aston, G.; Anderson, M. S.

    1992-01-01

    VICONOPT calculates vibrations and instabilities of assemblies of prismatic plates. Designed for efficient, accurate analysis of buckling and vibration, and for optimum design of panels of composite materials. Written in FORTRAN 77.

  4. Create Your Plate

    Medline Plus

    Full Text Available ... Your Plate Gluten Free Diets Meal Planning for Vegetarian Diets Cook with Heart-Healthy Foods Holiday Meal Planning What Can I Eat? Making Healthy Food Choices Diabetes Superfoods Non-starchy Vegetables Grains and Starchy Vegetables ...

  5. Create Your Plate

    Medline Plus

    Full Text Available ... Recipes Association Cookbook Recipes Planning Meals Diabetes Meal Plans Create Your Plate Gluten Free Diets Meal Planning ... serving of dairy or both as your meal plan allows. Choose healthy fats in small amounts. For ...

  6. Create Your Plate

    Medline Plus

    Full Text Available ... 1 Diabetes Get Started Safely Get And Stay Fit Types of Activity Weight Loss Assess Your Lifestyle ... manage portion control wherever you are. Now, our best-selling, sectioned to-go plate with easy-sealing ...

  7. Create Your Plate

    Medline Plus

    Full Text Available ... Plate is a simple and effective way to manage your blood glucose levels and lose weight. With ... been easier. It can be a challenge to manage portion control wherever you are. Now, our best- ...

  8. Tectonic Plate Movement.

    Science.gov (United States)

    Landalf, Helen

    1998-01-01

    Presents an activity that employs movement to enable students to understand concepts related to plate tectonics. Argues that movement brings topics to life in a concrete way and helps children retain knowledge. (DDR)

  9. Create Your Plate

    Medline Plus

    Full Text Available ... Carbohydrates Carbohydrate Counting Make Your Carbs Count Glycemic ... to manage portion control wherever you are. Now, our best-selling, sectioned to-go plate with easy-sealing ...

  10. Nonlinear dynamic buckling of stiffened plates under in-plane impact load

    Institute of Scientific and Technical Information of China (English)

    张涛; 刘土光; 赵耀; 罗家智

    2004-01-01

    This paper presents a simple solution of the dynamic buckling of stiffened plates under in-plane impact loading. Based on large deflection theory, a discretely stiffened plate model has been used. The tangential stresses of stiffeners and in-plane displacement are neglected. Appling the Hamilton's principle, the motion equations of stiffened plates are obtained. The deflection of the plate is taken as Fourier series, and using Galerkin method the discrete equations can be deduced, which can be solved easily by Runge-Kutta method. The dynamic buckling loads of the stiffened plates are obtained form Budiansky-Roth criterion.

  11. DYNAMIC BUCKLING OF STIFFENED PLATES UNDER FLUID-SOLID IMPACT LOAD

    Institute of Scientific and Technical Information of China (English)

    张涛; 刘土光; 熊有伦; 张维衡

    2004-01-01

    A simple solution of the dynamic buckling of stiffened plates under fluid-solid impact loading is presented. Based on large deflection theory, a discretely stiffened plate model has been used. The tangential stresses of stiffeners and in-plane displacement are neglected. Applying the Hamilton' s principle, the motion equations of stiffened plates are obtained. The deflection of the plate is taken as Fourier series, and using Galerkin method,the discrete equations can be deduced, which can be solved easily by Runge-Kutta method.The dynamic buckling loads of the stiffened plates are obtained from Budiansky-Roth ( B-R )curves.

  12. Origami - Folded Plate Structures

    OpenAIRE

    Buri, Hans Ulrich

    2010-01-01

    This research investigates new methods of designing folded plate structures that can be built with cross-laminated timber panels. Folded plate structures are attractive to both architects and engineers for their structural, spatial, and plastic qualities. Thin surfaces can be stiffened by a series of folds, and thus not only cover space, but also act as load bearing elements. The variation of light and shadow along the folded faces emphasizes the plas...

  13. Fractal multifiber microchannel plates

    Science.gov (United States)

    Cook, Lee M.; Feller, W. B.; Kenter, Almus T.; Chappell, Jon H.

    1992-01-01

    The construction and performance of microchannel plates (MCPs) made using fractal tiling mehtods are reviewed. MCPs with 40 mm active areas having near-perfect channel ordering were produced. These plates demonstrated electrical performance characteristics equivalent to conventionally constructed MCPs. These apparently are the first MCPs which have a sufficiently high degree of order to permit single channel addressability. Potential applications for these devices and the prospects for further development are discussed.

  14. Dynamic signatures of driven vortex motion.

    Energy Technology Data Exchange (ETDEWEB)

    Crabtree, G. W.; Kwok, W. K.; Lopez, D.; Olsson, R. J.; Paulius, L. M.; Petrean, A. M.; Safar, H.

    1999-09-16

    We probe the dynamic nature of driven vortex motion in superconductors with a new type of transport experiment. An inhomogeneous Lorentz driving force is applied to the sample, inducing vortex velocity gradients that distinguish the hydrodynamic motion of the vortex liquid from the elastic and-plastic motion of the vortex solid. We observe elastic depinning of the vortex lattice at the critical current, and shear induced plastic slip of the lattice at high Lorentz force gradients.

  15. Vibration and Buckling of Web Plate of the Plate Girder

    OpenAIRE

    高橋, 和雄; 呉, 明強; 中澤, 聡志; 筑紫, 宏之

    1998-01-01

    The vibration and buckling of the web of the plate girder are studied in this paper. The small deflection theory of the thin plate is used. The finite strip method is employed to solve vibration and buckling of the plate girder. Natural frequenies of buckling properties are shown for various plate girder bridges.

  16. Motion in radiotherapy

    DEFF Research Database (Denmark)

    Korreman, Stine Sofia

    2012-01-01

    This review considers the management of motion in photon radiation therapy. An overview is given of magnitudes and variability of motion of various structures and organs, and how the motion affects images by producing artifacts and blurring. Imaging of motion is described, including 4DCT and 4DPET...

  17. Proximal Humeral Fractures: A Biomechanical Comparison of Locking Plate Constructs in a Cadaveric 3-Part Fracture Model

    OpenAIRE

    2010-01-01

    The purpose of our study was to biomechanically compare, under cyclic loading conditions, fracture site motion, humeral head collapse, and intra-articular hardware penetration in simulated 3-part osteoporotic proximal humeral fractures stabilized with 1 of 2 locking-plate constructs. We performed fixation on simulated 3-part proximal humeral fractures in 10 pairs of cadaveric osteoporotic humeri with a Hand Innovations S3 Proximal Humerus Plate (S3 plate) or an LCP Proximal Humerus Plate (LCP...

  18. Past and present seafloor age distributions and the temporal evolution of plate tectonic heat transport

    Science.gov (United States)

    Becker, Thorsten W.; Conrad, Clinton P.; Buffett, Bruce; Müller, R. Dietmar

    2009-02-01

    Variations in Earth's rates of seafloor generation and recycling have far-reaching consequences for sea level, ocean chemistry, and climate. However, there is little agreement on the correct parameterization for the time-dependent evolution of plate motions. A strong constraint is given by seafloor age distributions, which are affected by variations in average spreading rate, ridge length, and the age distribution of seafloor being removed by subduction. Using a simplified evolution model, we explore which physical parameterizations of these quantities are compatible with broad trends in the area per seafloor age statistics for the present-day and back to 140 Ma from paleo-age reconstructions. We show that a probability of subduction based on plate buoyancy (slab-pull, or "sqrt(age)") and a time-varying spreading rate fits the observed age distributions as well as, or better than, a subduction probability consistent with an unvarying "triangular" age distribution and age-independent destruction of ocean floor. Instead, we interpret the present near-triangular distribution of ages as a snapshot of a transient state of the evolving oceanic plate system. Current seafloor ages still contain hints of a ˜ 60 Myr periodicity in seafloor production, and using paleoages, we find that a ˜ 250 Myr period variation is consistent with geologically-based reconstructions of production rate variations. These long-period variations also imply a decrease of oceanic heat flow by ˜ - 0.25%/Ma during the last 140 Ma, caused by a 25-50% decrease in the rate of seafloor production. Our study offers an improved understanding of the non-uniformitarian evolution of plate tectonics and the interplay between continental cycles and the self-organization of the oceanic plates.

  19. Improved Zone Plate Coded Imaging Technique by Using Four Special Designed Gabor Zone Plates

    Institute of Scientific and Technical Information of China (English)

    CAO Lei-Feng; SHEN Yu-Ji; ZHENG Zhi-Jian; DING Yong-Kun

    2005-01-01

    @@ Direct-current component, high-order artifacts, and side lobe distortion provide serious drawbacks in the application of Fresnel zone plate coded imaging (ZPCI).The presentation provided here proposes a novel way to resolve all the above-mentioned problems.Four different Gabor zone plates are suggested to substitute the one Fresnel zone plate used in the conventional ZPCI.Perfect reconstruction will be obtained when integrally analysing the four coded images.Primary numerical simulation provided here shows good result.

  20. A Comprehensive Study of Internal Distraction Plating, an Alternative Method for Distal Radius Fractures

    Science.gov (United States)

    Mavani, Kinjal J

    2016-01-01

    Introduction The management of highly comminuted distal radius fractures still remains a major treatment challenge. Articular comminution and compromised bone quality are the culprits. One novel approach is the technique of Internal Distraction Plating which involves “bridging” the fracture with the use of a standard 3.5mm plate applied dorsally in distraction from the radius, proximal to the fracture, to the long finger metacarpal distally, bypassing the comminuted segment. The plate is removed once fracture union has been achieved. Aim The present study was conducted with the aim to evaluate the role of internal dorsal distraction plating as an alternative method in the treatment of fracture distal radius in terms of special indications, technique and outcome. Materials and Methods This study was a prospective longitudinal study on 20 patients (mean age 62 years) treated with internal distraction plating for comminuted distal radius fractures with specific indications. Regular follow-ups with standard radiographs and analysis were done upto 24 months. Functional outcome were assessed by DASH Score and the Gartland and Werley demerit score. Results At final follow-up, all fractures had united and X-rays showed mean palmar tilt of 7°, positive ulnar variance of 0.5mm, radial inclination of 18° and average loss of 2mm of radial height. Mean range of motion values for wrist flexion 46°, extension 50°, pronation 79° and supination 77° At final follow-up, the mean DASH score was 32. 85% patient had excellent to good result as per Gartland and Werley demerit score. This construct has yield satisfactory clinical and radiographic results with these very challenging injuries. Conclusion The purpose of this study was to report the radiographic and the functional outcomes of treatment with this technique. External fixator and volar plating in communited distal end radius fractures are not always satisfactory in old age with osteoporotic bone because of

  1. Long-term exhumation of landscapes along the Pacific-North American plate boundary as inferred from apatite (U-Th)/He and ArcGIS analyses

    OpenAIRE

    Buscher, Jamie Todd

    2007-01-01

    The Pacific-North American plate boundary is typified by transpression and convergence, yet the relationship between interplate deformation and long-term crustal shortening is not fully understood. The continuous belt of rugged topography that extends along the entire plate boundary is generally associated with oblique tectonic plate motion, strong interplate coupling, and terrane accretion, but relating plate boundary orogenesis to variations in plate geometry and behavior requires detailed ...

  2. Global plate boundary evolution and kinematics since the late Paleozoic

    Science.gov (United States)

    Matthews, Kara J.; Maloney, Kayla T.; Zahirovic, Sabin; Williams, Simon E.; Seton, Maria; Müller, R. Dietmar

    2016-11-01

    Many aspects of deep-time Earth System models, including mantle convection, paleoclimatology, paleobiogeography and the deep Earth carbon cycle, require high-resolution plate motion models that include the evolution of the mosaic of plate boundaries through time. We present the first continuous late Paleozoic to present-day global plate model with evolving plate boundaries, building on and extending two previously published models for the late Paleozoic (410-250 Ma) and Mesozoic-Cenozoic (230-0 Ma). We ensure continuity during the 250-230 Ma transition period between the two models, update the absolute reference frame of the Mesozoic-Cenozoic model and add a new Paleozoic reconstruction for the Baltica-derived Alexander Terrane, now accreted to western North America. This 410-0 Ma open access model provides a framework for deep-time whole Earth modelling and acts as a base for future extensions and refinement. We analyse the model in terms of the number of plates, predicted plate size distribution, plate and continental root mean square (RMS) speeds, plate velocities and trench migration through time. Overall model trends share many similarities to those for recent times, which we use as a first order benchmark against which to compare the model and identify targets for future model refinement. Except for during the period 260-160 Ma, the number of plates (16-46) and ratio of "large" plates (≥ 107.5 km2) to smaller plates ( 2.7-6.6) are fairly similar to present-day values (46 and 6.6, respectively), with lower values occurring during late Paleozoic assembly and growth of Pangea. This temporal pattern may also reflect difficulties in reconstructing small, now subducted oceanic plates further back in time, as well as whether a supercontinent is assembling or breaking up. During the 260-160 Ma timeframe the model reaches a minima in the number of plates, in contrast to what we would expect during initial Pangea breakup and thus highlighting the need for refinement

  3. Tectonics of the Nazca-Antarctic plate boundary

    Science.gov (United States)

    Anderson-Fontana, Sandra; Larson, Roger L.; Engeln, Joseph F.; Lundgren, Paul; Stein, Seth

    1987-01-01

    A new bathymetric chart of part of the Chile transform system is constructed, based mainly on an R/V Endeavor survey from 100 deg W to its intersection with the East Ridge of the Juan Fernandez microplate. A generally continuous lineated trend can be followed through the entire region, with the transform valley being relatively narrow and well-defined from 109 deg W to approximately 104 deg 30 min W. The fracture zone then widens to the east, with at least two probable en echelon offsets to the south at 104 deg and 102 deg W. Six new strike-slip mechanisms along the Chile Transform and one normal fault mechanism near the northern end of the Chile Rise, inverted together with other plate-motion data from the eastern portion of the boundary, produce a new best-fit Euler pole for the Nazca-Antarctic plate pair, providing tighter constraints on the relative plate motions.

  4. Tectonics of the Nazca-Antarctic plate boundary

    Science.gov (United States)

    Anderson-Fontana, Sandra; Larson, Roger L.; Engeln, Joseph F.; Lundgren, Paul; Stein, Seth

    1987-01-01

    A new bathymetric chart of part of the Chile transform system is constructed, based mainly on an R/V Endeavor survey from 100 deg W to its intersection with the East Ridge of the Juan Fernandez microplate. A generally continuous lineated trend can be followed through the entire region, with the transform valley being relatively narrow and well-defined from 109 deg W to approximately 104 deg 30 min W. The fracture zone then widens to the east, with at least two probable en echelon offsets to the south at 104 deg and 102 deg W. Six new strike-slip mechanisms along the Chile Transform and one normal fault mechanism near the northern end of the Chile Rise, inverted together with other plate-motion data from the eastern portion of the boundary, produce a new best-fit Euler pole for the Nazca-Antarctic plate pair, providing tighter constraints on the relative plate motions.

  5. A judging principle of crucial vibrational transmission paths in plates

    Science.gov (United States)

    Wang, Bin; Li, Dong-Xu; Jiang, Jian-Ping; Liao, Yi-Huan

    2016-10-01

    This paper developed a judging principle of crucial vibrational transmission path (VTP) in plates. Novel generalized definitions of VTPs are given referred to the meaning of streamlines. And by comparing governing equations, the similarity between energy flow and fluid motion is firstly found so that an analytic method of VTPs in plates is proposed by analogy with fluid motion. Hereafter, the crucial VTP is defined for energy flows at objective points and relative judging criteria is given. Finally, based on two numerical experiments of passive control, the judging principle is indirectly verified by comparing the reduction effects of energy flows at focused points and relative judgment results of crucial VTPs. This paper is meaningful for analyzing and applying the VTPs in plates to guide the control design in future.

  6. Quantitative morphometric study of the subaxial cervical vertebrae end plate.

    Science.gov (United States)

    Feng, Hang; Fang, Xiangyi; Huang, Dageng; Yu, Chengcheng; Zhao, Songchuan; Hao, Dingjun

    2017-02-01

    Cervical disc arthroplasty has been gradually adopted as an alternative for the treatment of cervical degenerative disease. However, there is a large discrepancy between footprints of currently available cervical disc prostheses and anatomic dimensions of cervical end plates. This study aimed to accurately and comprehensively quantify the three-dimensional (3D) anatomic morphology of the cervical vertebral end plate and provide a theoretical basis for designing appropriate disc prostheses. Moreover, we introduced a novel geometric and mechanical model for 3D reconstruction techniques of the cervical end plate. A descriptive study of the geometry of the middle and lower cervical vertebral end plates in cadaveric spines was carried out. A total of 138 cervical vertebral end plates were digitized using an optical 3D range scanning system, and then each end plate was reconstructed using the digitized image. For each end plate, the morphologic characteristics of six surface curves and the end plate concavity depth were symmetrically chosen and depicted. The cranial end plates (relative to the disc) were concave and the caudal end plates were relatively flat at all disc levels, with mean concavity depths of 2.04 and 0.69 mm, respectively. For the caudal end plates, the end plate concavity apex was most often (81.42%) located in the posterior portion, whereas in the cranial end plates, the distribution was relatively even. For the sagittal curves, the foremost point and the rearmost point on the middle curve had a more forward position than those in the left curve and the right curve. Regarding the frontal plane curves, the length of the middle curve was longer than that of the anterior curve and posterior curve. For the cranial end plate, the maximal mean depth was the middle curve, whereas for the caudal end plate, the maximum depth was the posterior curve. There is marked morphologic asymmetry, in that the cranial end plate is more concave than the corresponding

  7. Attitudes toward Motion Pictures among College Students.

    Science.gov (United States)

    Austin, Bruce A.

    Several reasons for studying motion pictures and patrons' attitudes toward them include the following: (1) current data show that motion pictures account for 53% of the total United States spectator amusement expenditures; (2) the average weekly United States movie attendance has plummeted by more than half since 1930; (3) despite this decline,…

  8. The StarScan plate measuring machine: overview and calibrations

    CERN Document Server

    Zacharias, Norbert; Holdenried, Ellis; de Cuyper, Jean-Pierre; Rafferty, Ted; Wycoff, Gary

    2008-01-01

    The StarScan machine at the U.S. Naval Observatory (USNO) completed measuring photographic astrograph plates to allow determination of proper motions for the USNO CCD Astrograph Catalog (UCAC) program. All applicable 1940 AGK2 plates, about 2200 Hamburg Zone Astrograph plates, 900 Black Birch (USNO Twin Astrograph) plates, and 300 Lick Astrograph plates have been measured. StarScan comprises of a CCD camera, telecentric lens, air-bearing granite table, stepper motor screws, and Heidenhain scales to operate in a step-stare mode. The repeatability of StarScan measures is about 0.2 micrometer. The CCD mapping as well as the global table coordinate system has been calibrated using a special dot calibration plate and the overall accuracy of StarScan x,y data is derived to be 0.5 micrometer. Application to real photographic plate data shows that position information of at least 0.65 micrometer accuracy can be extracted from course grain 103a-type emulsion astrometric plates. Transformations between "direct" and "re...

  9. Congruency of scapula locking plates: implications for implant design.

    Science.gov (United States)

    Park, Andrew Y; DiStefano, James G; Nguyen, Thuc-Quyen; Buckley, Jenni M; Montgomery, William H; Grimsrud, Chris D

    2012-04-01

    We conducted a study to evaluate the congruency of fit of current scapular plate designs. Three-dimensional image-processing and -analysis software, and computed tomography scans of 12 cadaveric scapulae were used to generate 3 measurements: mean distance from plate to bone, maximum distance, and percentage of plate surface within 2 mm of bone. These measurements were used to quantify congruency. The scapular spine plate had the most congruent fit in all 3 measured variables. The lateral border and glenoid plates performed statistically as well as the scapular spine plate in at least 1 of the measured variables. The medial border plate had the least optimal measurements in all 3 variables. With locking-plate technology used in a wide variety of anatomical locations, the locking scapula plate system can allow for a fixed-angle construct in this region. Our study results showed that the scapular spine, glenoid, and lateral border plates are adequate in terms of congruency. However, design improvements may be necessary for the medial border plate. In addition, we describe a novel method for quantifying hardware congruency, a method that can be applied to any anatomical location.

  10. Efficient transport of droplet sandwiched between saw-tooth plates.

    Science.gov (United States)

    Wang, Liya; Wu, Hengan; Wang, Fengchao

    2016-01-15

    The transport of droplet sandwiched between smooth and saw-tooth plates was investigated using molecular dynamics method. The repeated opening and closing of the plates result in sequential stretching and squeezing of the droplet, which provide the driving force. The asymmetrical saw tooth obstructs the backward motion of the droplet, and gives rise to a net forward displacement of the droplet in every opening and closing cycle. This unidirectional motion facilitates the efficient droplet transport, which is referred to as the ratchet-like effect in this work. Our simulations also reveal that the influence of the surface wettability on the droplet transport is different for saw-tooth and smooth plates. Droplet transport efficiency exhibits monotonic decrease with the increase of the solid-liquid interactions for saw-tooth plates. While for smooth plates, unidirectional droplet movement was only observed for certain solid-liquid interactions. Taken together these simulation results and theoretical analysis, we demonstrate that hydrophobic saw-tooth plates can improve the transport efficiency significantly. These findings not only enhance our understanding of the droplet transport from atomistic scale, but also are beneficial to practical applications in designing of micro- and nano-fluidic systems.

  11. Bending and stretching of plates

    CERN Document Server

    Mansfield, E H; Hemp, W S

    1964-01-01

    The Bending and Stretching of Plates deals with elastic plate theory, particularly on small- and large-deflexion theory. Small-deflexion theory concerns derivation of basic equations, rectangular plates, plates of various shapes, plates whose boundaries are amenable to conformal transformation, plates with variable rigidity, and approximate methods. Large-deflexion theory includes general equations and some exact solutions, approximate methods in large-deflexion theory, asymptotic large-deflexion theories for very thin plates. Asymptotic theories covers membrane theory, tension field theory, a

  12. Global strike-slip faults: Bounds from plate tectonics

    Science.gov (United States)

    Gordon, R. G.; Argus, D. F.

    2006-12-01

    According to the tenets of plate tectonics, a transform fault is a strike-slip fault along which neither convergence nor divergence occurs. Analysis of global plate motion data indicates that the only true transform faults are the strike-slip faults that offset segments of mid-ocean ridges. Thus, many of Earth's major strike-slip fault systems are not true transform faults as they accommodate large components of oblique convergence or oblique divergence. This is particularly true for several important ocean-continent systems such as the San Andreas, the strike-slip systems bounding the northern and southern Caribbean plate, the Alpine fault system of New Zealand, the Anatolian fault system, and the Azores-Gibraltar-Alboran sea system. These strike-slip systems are commonly sites of large scale mountain building and basin formation. Here we examine the far-field constraints on the motions of the plates bounding several of these strike-slip systems using both conventional plate motion circuits and results from global positioning system and other space geodetic data. We pay particular attention to the San Andreas fault system in central and northern California, where the San Andreas system is part of the boundary between the Sierran microplate and the Pacific plate. Most of the fault system accommodates obliquely convergent motion, giving rise to the California Coast Range, but in the northern San Francisco Bay Area it is obliquely divergent, producing San Pablo Bay and a gap in the Coast Range that permits the Sierran watershed to drain to the Pacific through the Golden Gate.

  13. The propagation characteristics of the plate modes of acoustic emission waves in thin aluminum plates and thin graphite/epoxy composite plates and tubes. Ph.D. Thesis - Johns Hopkins Univ., 1991

    Science.gov (United States)

    Prosser, William H.

    1991-01-01

    Acoustic emission was interpreted as modes of vibration in plates. Classical plate theory was used to predict dispersion curves for the two fundamental modes and to calculate the shapes of flexural waveforms produced by vertical step function loading. There was good agreement between theoretical and experimental results for aluminum. Composite materials required the use of a higher order plate theory (Reissner-Mindlin) to get good agreement with the measured velocities. Four composite plates with different laminate stacking sequences were studied. The dispersion curves were determined from phase spectra of the time dependent waveforms. Plate modes were shown to be useful for determining the direction of source motion. Aluminum plates were loaded by breaking a pencil lead against their surface. By machining slots at angles to the plane of a plate, the direction in which the force acted was varied. Changing the source motion direction produced regular variations in the waveforms. To demonstrate applicability beyond simple plates, waveforms produced by lead breaks on a thin walled composite tube were also shown to be interpretable as plate modes. The tube design was based on the type of struts proposed for Space Station Freedom's trussed structures.

  14. The transition from linear to diffuse plate boundary in the Azores-Gibraltar region: results from a thin-sheet model

    Science.gov (United States)

    Jiménez-Munt, Ivone; Fernàndez, Manel; Torne, Montse; Bird, Peter

    2001-10-01

    We use the thin-sheet plane-stress approach to study the present-day dynamic behavior of the plate boundary between Eurasia and Africa along the Azores-Gibraltar region. This plate boundary, which extends from the Azores triple junction to the Gibraltar strait, shows a tectonic regime that changes from transtension in the west to transpression in the east, with a strike-slip motion in its central segment. Seismological data reveal that the western and central segments are currently marked by a linear series of earthquakes indicating that the plate boundary is located in a narrow zone. In contrast, the eastern segment is not so well defined and deformation spreads over a much broader area. To apply the thin-sheet approach, we combined heat flow, elevation and crustal thickness data to calculate the steady-state geotherm and the total strength of the lithosphere. Several models with different fault friction coefficients and geometries at the eastern segment of the plate boundary were tested. Results are compared with the maximum compressive stress directions from the World Stress Map, and the calculated seismic strain rates and slip vectors from earthquake data. The best fitting models are consistent with the rotation pole of Argus et al. [D.F. Argus et al., J. Geophys. Res. 94 (1989) 5585-5602], and show that the rheological behavior of the plate boundary must necessarily change from the western and central segments to the eastern segment. The diffuse character of the plate boundary east of the Gorringe Bank is dominated by the transition from oceanic to continental lithosphere, the weakness of the Alboran domain, and the convergence between the African and the Eurasian plates. The displacement of the Alboran domain relative to the African plate may play a major role in stress propagation through the Iberian Peninsula and its Atlantic margin.

  15. Interbody device endplate engagement effects on motion segment biomechanics.

    Science.gov (United States)

    Buttermann, Glenn R; Beaubien, Brian P; Freeman, Andrew L; Stoll, James E; Chappuis, James L

    2009-07-01

    with endplate spikes or threads reduced ROM by approximately 50% and NZ by approximately 60% in flexion-extension (p< or =.02). Only the cage with endplate spikes provided a statistically significant reduction in axial torsion ROM compared with the intact state (50% decrease, p<.001). Posterior fixation provided a significant reduction in ROM in all directions versus the interbody device alone (p<.001). Anterior plating decreased ROM over interbody device alone in flexion-extension and torsion but did not have additional effect on lateral bending ROM. The cages with endplate spikes or threads provide substantial motion segment rigidity compared with intact in bending modes. Only the cages with endplate spikes were more rigid than intact in torsion. All devices experienced increased rigidity with anterior plating and even greater rigidity with posterior fixation. It appears that the endplate engagement with spikes may be beneficial in limiting torsion, which is generally difficult with other "stand-alone" devices tested in the current and prior reports.

  16. Anterior cervical plating

    Directory of Open Access Journals (Sweden)

    Gonugunta V

    2005-01-01

    Full Text Available Although anterior cervical instrumentation was initially used in cervical trauma, because of obvious benefits, indications for its use have been expanded over time to degenerative cases as well as tumor and infection of the cervical spine. Along with a threefold increase in incidence of cervical fusion surgery, implant designs have evolved over the last three decades. Observation of graft subsidence and phenomenon of stress shielding led to the development of the new generation dynamic anterior cervical plating systems. Anterior cervical plating does not conclusively improve clinical outcome of the patients, but certainly enhances the efficacy of autograft and allograft fusion and lessens the rate of pseudoarthrosis and kyphosis after multilevel discectomy and fusions. A review of biomechanics, surgical technique, indications, complications and results of various anterior cervical plating systems is presented here to enable clinicians to select the appropriate construct design.

  17. Characterization of gold and nickel coating on AISI 304 stainless steel for use in the fabrication of current collector plates for fuel cells; Caracterizacion de recubrimientos de oro y niquel realizados sobre acero inoxidable AISI 304 para su empleo en la fabricacion de placas colectoras de corriente para celdas de combustible

    Energy Technology Data Exchange (ETDEWEB)

    Flores Hernandez, J. Roberto [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)] e-mail: jrflores@iie.org.mx; Aguilar Gama, M. Tulio [UNAM. Facultad de Quimica, Mexico D.F. (Mexico); Cano Castillo, Ulises; Albarran, Lorena [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Olvera, J. Carlos; Orozco, German [CIDETEQ, Pedro Escobedo, Queretaro (Mexico)

    2009-09-15

    Among the different components that compose fuel cell technology (MEA, bipolar plates, seals, etc.) current collector plates play an important role in the good performance of fuel cells, since they collect all of the current generated and distribute it to the external circuit. Therefore, the most important properties that the current collector plates should have are excellent conductivity and good resistance to the corrosive conditions present in the fuel cell. This document presents results obtained during the nickel and gold electrodeposition process on AISI 304 stainless steel and the morphology and thickness of each coating, their adhesion, hardness and conductivity values. Finally, results obtained during some of the electrochemical tests performed on the coatings are shown. [Spanish] De los diferentes componentes que integran la tecnologia de celdas de combustible (MEA's, placas bipolares, sellos, etc.), las placas colectoras de corriente tienen un importante rol en el buen desempeno de la celdas de combustibles, ya que en estas placas se colecta toda la corriente generada y se distribuye al circuito externo. Debido a esto, las propiedades mas importantes que deben tener las placas colectaras de corriente son: excelente conductividad y buena resistencia a las condiciones corrosivas presentes en la celda de combustible. En este documento se presentan los resultados obtenidos en el proceso de electrodeposicion de niquel y oro sobre acero inoxidable AISI 304, asi como la morfologia y el espesor de cada recubrimiento, sus valores de adherencia, dureza y conductividad. Finalmente se muestran tambien los resultados obtenidos de algunas pruebas electroquimicas a los que fueron sometidos los recubrimientos.

  18. Condylar orientation plating in comminuted intraarticular fractures of adult distal humerus

    Directory of Open Access Journals (Sweden)

    Sukhendu Sarkhel

    2015-01-01

    Conclusion: Excellent pain free range of motion with a high rate of union can be achieved in comminuted intraarticular distal humerus fractures in adults with the use of condylar orientation precontoured plating technique. Condylar orientation is very important with perfect articular congruity in elbow motion.

  19. License plate detection algorithm

    Science.gov (United States)

    Broitman, Michael; Klopovsky, Yuri; Silinskis, Normunds

    2013-12-01

    A novel algorithm for vehicle license plates localization is proposed. The algorithm is based on pixel intensity transition gradient analysis. Near to 2500 natural-scene gray-level vehicle images of different backgrounds and ambient illumination was tested. The best set of algorithm's parameters produces detection rate up to 0.94. Taking into account abnormal camera location during our tests and therefore geometrical distortion and troubles from trees this result could be considered as passable. Correlation between source data, such as license Plate dimensions and texture, cameras location and others, and parameters of algorithm were also defined.

  20. Random vibrations of composite beams and plates

    Science.gov (United States)

    Abdelnaser, Ahmad Shehadeh

    In this study, a generalized modal approach is presented to solve more general vibration problems of composite beams and plates. The coupled systems of partial differential equations, representing the equations of motion, are uncoupled into modal equations by utilizing the eigenfunctions of the system and its adjoint. A method is presented to obtain these eigenfunctions for beams with arbitrary boundary conditions and for plates with Levy-type boundary conditions. The forced vibration solutions obtained by this method are then used to calculate the random response characteristics of beams and plates subjected to spatially and temporally correlated random loads. In the analysis of beams, both symmetric cross-ply and angle-ply configurations have been considered. In the symmetric cross-ply configuration with no torsional loads, of course, the warping effects are absent. The angle-ply case, however, includes torsion-warping effects and coupled bending-torsion motions. A simple displacement field is introduced to reflect warping in the third-order shear deformation theory. In the analysis of plates two configurations of the laminates have also been considered: symmetric cross-ply and antisymmetric angle-ply. At this time, these are the only two configurations which can be solved by the closed-form modal analysis approach for the Levy-type boundary conditions. In both cases of the beams and plates, the numerical results with and without shear deformations are obtained and compared. The result for no shear deformation theory are obtained with the classical lamination theory. The results have also been obtained for the first-order shear deformation theory with a somewhat simpler displacement field which has been commonly used in the past. The numerical results are obtained for the global response quantities such as frequencies, displacements, and crossing rates as well as for the local response quantities such as normal and shear stresses across a cross section. The

  1. Subduction controls the distribution and fragmentation of Earth’s tectonic plates.

    Science.gov (United States)

    Mallard, Claire; Coltice, Nicolas; Seton, Maria; Müller, R Dietmar; Tackley, Paul J

    2016-07-07

    The theory of plate tectonics describes how the surface of Earth is split into an organized jigsaw of seven large plates of similar sizes and a population of smaller plates whose areas follow a fractal distribution. The reconstruction of global tectonics during the past 200 million years suggests that this layout is probably a long-term feature of Earth, but the forces governing it are unknown. Previous studies, primarily based on the statistical properties of plate distributions, were unable to resolve how the size of the plates is determined by the properties of the lithosphere and the underlying mantle convection. Here we demonstrate that the plate layout of Earth is produced by a dynamic feedback between mantle convection and the strength of the lithosphere. Using three-dimensional spherical models of mantle convection that self-consistently produce the plate size–frequency distribution observed for Earth, we show that subduction geometry drives the tectonic fragmentation that generates plates. The spacing between the slabs controls the layout of large plates, and the stresses caused by the bending of trenches break plates into smaller fragments. Our results explain why the fast evolution in small back-arc plates reflects the marked changes in plate motions during times of major reorganizations. Our study opens the way to using convection simulations with plate-like behaviour to unravel how global tectonics and mantle convection are dynamically connected.

  2. Subduction controls the distribution and fragmentation of Earth’s tectonic plates

    Science.gov (United States)

    Mallard, Claire; Coltice, Nicolas; Seton, Maria; Müller, R. Dietmar; Tackley, Paul J.

    2016-07-01

    The theory of plate tectonics describes how the surface of Earth is split into an organized jigsaw of seven large plates of similar sizes and a population of smaller plates whose areas follow a fractal distribution. The reconstruction of global tectonics during the past 200 million years suggests that this layout is probably a long-term feature of Earth, but the forces governing it are unknown. Previous studies, primarily based on the statistical properties of plate distributions, were unable to resolve how the size of the plates is determined by the properties of the lithosphere and the underlying mantle convection. Here we demonstrate that the plate layout of Earth is produced by a dynamic feedback between mantle convection and the strength of the lithosphere. Using three-dimensional spherical models of mantle convection that self-consistently produce the plate size-frequency distribution observed for Earth, we show that subduction geometry drives the tectonic fragmentation that generates plates. The spacing between the slabs controls the layout of large plates, and the stresses caused by the bending of trenches break plates into smaller fragments. Our results explain why the fast evolution in small back-arc plates reflects the marked changes in plate motions during times of major reorganizations. Our study opens the way to using convection simulations with plate-like behaviour to unravel how global tectonics and mantle convection are dynamically connected.

  3. Direct Contribution of Auditory Motion Information to Sound-Induced Visual Motion Perception

    Directory of Open Access Journals (Sweden)

    Souta Hidaka

    2011-10-01

    Full Text Available We have recently demonstrated that alternating left-right sound sources induce motion perception to static visual stimuli along the horizontal plane (SIVM: sound-induced visual motion perception, Hidaka et al., 2009. The aim of the current study was to elucidate whether auditory motion signals, rather than auditory positional signals, can directly contribute to the SIVM. We presented static visual flashes at retinal locations outside the fovea together with a lateral auditory motion provided by a virtual stereo noise source smoothly shifting in the horizontal plane. The flashes appeared to move in the situation where auditory positional information would have little influence on the perceived position of visual stimuli; the spatiotemporal position of the flashes was in the middle of the auditory motion trajectory. Furthermore, the auditory motion altered visual motion perception in a global motion display; in this display, different localized motion signals of multiple visual stimuli were combined to produce a coherent visual motion perception so that there was no clear one-to-one correspondence between the auditory stimuli and each visual stimulus. These findings suggest the existence of direct interactions between the auditory and visual modalities in motion processing and motion perception.

  4. Casimir force between metal plate and dielectric plate

    Institute of Scientific and Technical Information of China (English)

    刘中柱; 邵成刚; 罗俊

    1999-01-01

    The Casimir effect between metal plate and dielectric plate is discussed with 1+1-dimensional potential model without using cut-off method. Calculation shows that the Casimir force between metal plate and dielectric plate is determined not only by the potential V0, the dielectric thickness and the distance α between the metal plate and dielectric plate, but also by the dimension of the vessel. When α is far less than the dimension of the vessel, the Casimir force Fc∝α(-1); conversely Fc∝α-2. This result is significant for Casimir force experiment.

  5. ANALYSIS OF GLOBAL DYNAMICS IN A PAIAMETIICALLY EXCITED THIN PLATE

    Institute of Scientific and Technical Information of China (English)

    张伟

    2001-01-01

    The global bifurcations and chaos of a simply supported rectangular thin plate with parametric excitation are analyzed. The formulas of the thin plate are derived by yon Karman type equation and Galerkin's approach. The method of multiple scales is used to obtain the averaged equations. Based on the averaged equations, the theory of the normal form is used to give the explicit expressions of the normal form associated with a double zero and a pair of pure imaginary eigenvalues by Maple program. On the basis of the normal form, a global bifurcation analysis of the parametrically excited recta ngular thin plate is given by the global perturbation method developed by Kovacic and Wiggins. The chaotic motion of thin plate is also found by numerical simulation.

  6. Cosmology as geodesic motion

    Energy Technology Data Exchange (ETDEWEB)

    Townsend, Paul K [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Wohlfarth, Mattias N R [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)

    2004-12-07

    For gravity coupled to N scalar fields, with arbitrary potential V, it is shown that all flat (homogeneous and isotropic) cosmologies correspond to geodesics in an (N + 1)-dimensional 'augmented' target space of Lorentzian signature (1, N), timelike if V > 0, null if V = 0 and spacelike if V < 0. Accelerating cosmologies correspond to timelike geodesics that lie within an 'acceleration subcone' of the 'lightcone'. Non-flat (k = {+-}1) cosmologies are shown to evolve as projections of geodesic motion in a space of dimension N + 2, of signature (1, N + 1) for k = -1 and signature (2, N) for k = +1. This formalism is illustrated by cosmological solutions of models with an exponential potential, which are comprehensively analysed; the late-time behaviour for other potentials of current interest is deduced by comparison.

  7. Cosmology as Geodesic Motion

    CERN Document Server

    Townsend, P K; Townsend, Paul K.; Wohlfarth, Mattias N.R.

    2004-01-01

    For gravity coupled to N scalar fields with arbitrary potential V, it is shown that all flat (homogeneous and isotropic) cosmologies correspond to geodesics in an (N+1)-dimensional `extended target space' of Lorentzian signature (1,N), timelike if V>0 and spacelike if V<0. Accelerating cosmologies correspond to timelike geodesics that lie within an `acceleration subcone' of the `lightcone'. Non-flat (k=-1,+1) cosmologies are shown to evolve as projections of geodesic motion in a space of dimension N+2, of signature (1,N+1) for k=-1 and signature (2,N) for k=+1. We illustrate these results for various potentials of current interest, including exponential and inverse power potentials.

  8. Nuclear reactor alignment plate configuration

    Energy Technology Data Exchange (ETDEWEB)

    Altman, David A; Forsyth, David R; Smith, Richard E; Singleton, Norman R

    2014-01-28

    An alignment plate that is attached to a core barrel of a pressurized water reactor and fits within slots within a top plate of a lower core shroud and upper core plate to maintain lateral alignment of the reactor internals. The alignment plate is connected to the core barrel through two vertically-spaced dowel pins that extend from the outside surface of the core barrel through a reinforcement pad and into corresponding holes in the alignment plate. Additionally, threaded fasteners are inserted around the perimeter of the reinforcement pad and into the alignment plate to further secure the alignment plate to the core barrel. A fillet weld also is deposited around the perimeter of the reinforcement pad. To accomodate thermal growth between the alignment plate and the core barrel, a gap is left above, below and at both sides of one of the dowel pins in the alignment plate holes through with the dowel pins pass.

  9. Contemporary vertical crustal motion in the Pacific Northwest

    Science.gov (United States)

    Holdahl, Sandford R.; Faucher, Francois; Dragert, Herb

    A map of recent vertical crustal motion has been compiled for coastal Washington and southwest British Columbia. Average velocities over the past 80 years were determined by least squares adjustment of repeated precise levelings and mean sea-level observations from 21 tide gauges. Annual variations in mean sea level were determined directly within the adjustment model under the assumption that they were identical at all tide gauges in a given year. The derived vertical velocities range from -2.0±0.9 mm/yr near Seattle, to 2.5±0.8 mm/yr at the northwest tip of the Olympic Peninsula, and over 3 mm/yr in the region to the north of Campbell River on Vancouver Island. Determination of a constant velocity in this latter region is complicated by about 10 cm of coseismic subsidence associated with a magnitude 7.3 earthquake in 1946, and an apparent increase in uplift rate over the past decade. Qualitatively, the regional velocity pattern is consistent with features of the current plate convergence model: 1) the rapid uplift of the region north of central Vancouver Island is consistent with the overriding of the young (Explorer Plate which may be underplating the coastal margin in this area; and 2) the ridge of uplift extending from the Neah Bay area north across Vancouver Island to Campbell River is consistent with a pattern expected from a locked subduction zone underlying this coastal region. The large-scale subsidence to the southwest of Puget Sound is more difficult to explain in the context of plate convergence.

  10. Multivariate respiratory motion prediction

    Science.gov (United States)

    Dürichen, R.; Wissel, T.; Ernst, F.; Schlaefer, A.; Schweikard, A.

    2014-10-01

    In extracranial robotic radiotherapy, tumour motion is compensated by tracking external and internal surrogates. To compensate system specific time delays, time series prediction of the external optical surrogates is used. We investigate whether the prediction accuracy can be increased by expanding the current clinical setup by an accelerometer, a strain belt and a flow sensor. Four previously published prediction algorithms are adapted to multivariate inputs—normalized least mean squares (nLMS), wavelet-based least mean squares (wLMS), support vector regression (SVR) and relevance vector machines (RVM)—and evaluated for three different prediction horizons. The measurement involves 18 subjects and consists of two phases, focusing on long term trends (M1) and breathing artefacts (M2). To select the most relevant and least redundant sensors, a sequential forward selection (SFS) method is proposed. Using a multivariate setting, the results show that the clinically used nLMS algorithm is susceptible to large outliers. In the case of irregular breathing (M2), the mean root mean square error (RMSE) of a univariate nLMS algorithm is 0.66 mm and can be decreased to 0.46 mm by a multivariate RVM model (best algorithm on average). To investigate the full potential of this approach, the optimal sensor combination was also estimated on the complete test set. The results indicate that a further decrease in RMSE is possible for RVM (to 0.42 mm). This motivates further research about sensor selection methods. Besides the optical surrogates, the sensors most frequently selected by the algorithms are the accelerometer and the strain belt. These sensors could be easily integrated in the current clinical setup and would allow a more precise motion compensation.

  11. Create Your Plate

    Medline Plus

    Full Text Available ... 1 Type 2 About Us Online Community Meal Planning Sign In Search: Search More Sites Search ≡ Are ... Fitness Home Food MyFoodAdvisor Recipes Association Cookbook Recipes Planning Meals Diabetes Meal Plans Create Your Plate Gluten ...

  12. Create Your Plate

    Medline Plus

    Full Text Available ... Create Your Plate is a simple and effective way to manage your blood glucose levels and lose weight. With ... year of delicious meals to help prevent and manage diabetes. Healthy Recipes: ... to your day with this guide. Ways to Give: Wear Your Cause on Your Sleeve - ...

  13. The Plate Tectonics Project

    Science.gov (United States)

    Hein, Annamae J.

    2011-01-01

    The Plate Tectonics Project is a multiday, inquiry-based unit that facilitates students as self-motivated learners. Reliable Web sites are offered to assist with lessons, and a summative rubric is used to facilitate the holistic nature of the project. After each topic (parts of the Earth, continental drift, etc.) is covered, the students will…

  14. Create Your Plate

    Medline Plus

    Full Text Available ... tax-deductible gift today can fund critical diabetes research and support vital diabetes education services that improve the ... way to manage your blood glucose levels and lose weight. With this method, you fill your plate with more non-starchy ...

  15. Create Your Plate

    Medline Plus

    Full Text Available ... 1 Type 2 About Us Online Community Meal Planning Sign In Search: Search More Sites Search ≡ Are ... Fitness Home Food MyFoodAdvisor Recipes Association Cookbook Recipes Planning Meals Diabetes Meal Plans Create Your Plate Gluten ...

  16. Create Your Plate

    Medline Plus

    Full Text Available ... tax-deductible gift today can fund critical diabetes research and support vital diabetes education services that improve the ... way to manage your blood glucose levels and lose weight. With this method, you fill your plate with more non-starchy ...

  17. Create Your Plate

    Medline Plus

    Full Text Available ... unsweetened tea or coffee. Featured Product Precise Portions® Go Healthy Travel Pack (4/Box) Taking the guesswork ... you are. Now, our best-selling, sectioned to-go plate with easy-sealing lid is offered in ...

  18. Create Your Plate

    Medline Plus

    Full Text Available ... manage portion control wherever you are. Now, our best-selling, sectioned to-go plate with easy-sealing lid is offered in a 4-pack. Whether ... Research & Practice We Are Research Leaders We Support Your Doctor ...

  19. INL HIP Plate Fabrication

    Energy Technology Data Exchange (ETDEWEB)

    B. H. Park; C. R. Clark; J. F. Jue

    2010-02-01

    This document outlines the process used to bond monolithic fuel plates by Hot Isostatic Pressing (HIP). This method was developed at Idaho National Laboratory (INL) for the Reduced Enrichment for Research and Test Reactors (RERTR) program. These foils have been used in a number of irradiation experiments in support of the United States Global Threat Reduction Initiative (GTRI) program.

  20. The Plate Tectonics Project

    Science.gov (United States)

    Hein, Annamae J.

    2011-01-01

    The Plate Tectonics Project is a multiday, inquiry-based unit that facilitates students as self-motivated learners. Reliable Web sites are offered to assist with lessons, and a summative rubric is used to facilitate the holistic nature of the project. After each topic (parts of the Earth, continental drift, etc.) is covered, the students will…

  1. Create Your Plate

    Medline Plus

    Full Text Available ... Planning Meals > Create Your Plate Share: Print Page Text Size: A A A Listen En Español Create ... somewhere in between, you have an easy portion control solution that works. Last Reviewed: October 8, 2015 Last Edited: ... Cost of Diabetes Advocate Toolkit Call to Congress Research & ...

  2. The mechanical behavior of locking compression plates compared with dynamic compression plates in a cadaver radius model.

    Science.gov (United States)

    Gardner, Michael J; Brophy, Robert H; Campbell, Deirdre; Mahajan, Amit; Wright, Timothy M; Helfet, David L; Lorich, Dean G

    2005-10-01

    The purpose of this cadaveric study was to compare the mechanical behavior of a locked compression plate, which uses threaded screw heads to create a fixed angle construct, with a dynamic compression plate construct in a cadaver radius model. Mechanical study with cyclic testing and high-speed optical motion analysis. Biomechanics laboratory at an academic institution. Eighteen pairs of fresh-frozen human cadaver radii were divided into 3 groups of 6 to be tested as a group in each of the following force applications: anteroposterior (AP) bending, mediolateral bending, or torsion. Each bone was osteotomized leaving a 5-mm fracture gap and then fixed with a plate. For each pair, 1 radius received a standard plate (limited-contact dynamic compression plates; LC-DCP), the contralateral radius was fixed with a locking compression plate (LCP), and specimens underwent cyclic loading. Normalized stiffness, average energy absorbed, and Newton-cycles to failure were calculated. In addition, a 3-dimensional, high-speed, infrared motion analysis system was used to evaluate motion at the fracture site. Construct stiffness, fracture site motion, cycles to failure, and energy absorption. Repeated measures ANOVA were used to detect differences between groups with time. In the torsion group, LCP specimens failed at 60% greater Newton-cycles than the LC-DCP (1473 vs. 918; P different biomechanical behavior with time. As cycling progressed in the LC-DCP specimens under torsion testing, stiffness (measured at the actuator at the bone ends) did not change significantly; however, fracture motion (measured at the fracture surfaces) decreased significantly (P = 0.04). The LCP specimens did not display similar behavior. Our findings indicated that LCP constructs may demonstrate subtle mechanical superiority compared with the LC-DCP. The LCP specimens had less energy absorption in the AP group and survived longer in the torsion group. Discordance of motion between measurement regions was

  3. CFD Simulation of the Vertical Motion Characteristics of the Moonpool Fluid for the Truss Spar

    Institute of Scientific and Technical Information of China (English)

    Bin Wang; Liqin Liu; Yougang Tang

    2014-01-01

    The research purpose of this paper is to estimate the impacts of the parameters of the guide plate on the vertical motion characteristics of the moonpool fluid. With the volume of fluid (VOF) method, three-dimensional models of the moonpool fluid motions of the truss spar platform are established. Simulation results are then presented for the moonpool forced oscillation by employing the dynamic mesh method and user-defined functions in FLUENT. The motions of the moonpool fluid and the loads on the guide plates are obtained for both cases of square-ring and crisscross. The results show that the shape and area of the guide plate at the bottom of the moonpool have a significant impact on the physical parameters of the moonpool, including the load on the moonpool guide plate, motion form of the moonpool fluid and the mass flow rate.

  4. Dizziness and Motion Sickness

    Science.gov (United States)

    ... ENTCareers Marketplace Find an ENT Doctor Near You Dizziness and Motion Sickness Dizziness and Motion Sickness Patient ... vision or speech, or hearing loss. What is dizziness? Dizziness can be described in many ways, such ...

  5. Consensus on melanonychia nail plate dermoscopy*

    Science.gov (United States)

    Chiacchio, Nilton Di; de Farias, Débora Cadore; Piraccini, Bianca Maria; Hirata, Sergio Henrique; Richert, Bertrand; Zaiac, Martin; Daniel, Ralph; Fanti, Pier Alessandro; Andre, Josette; Ruben, Beth S; Fleckman, Philip; Rich, Phoebe; Haneke, Eckart; Chang, Patricia; Cherit, Judith Dominguez; Scher, Richard; Tosti, Antonella

    2013-01-01

    This statement, focused on melanonychia and nail plate dermoscopy, is intended to guide medical professionals working with melanonychia and to assist choosing appropriate management for melanonychia patients. The International Study Group on Melanonychia was founded in 2007 and currently has 30 members, including nail experts and dermatopathologists with special expertise in nails. The need for common definitions of nail plate dermoscopy was addressed during the Second Meeting of this Group held in February 2008. Prior to this meeting and to date (2010) there have been no evidence-based guidelines on the use of dermoscopy in the management of nail pigmentation. PMID:23739699

  6. Water wave scattering by an elastic thin vertical plate submerged in finite depth water

    Science.gov (United States)

    Chakraborty, Rumpa; Mandal, B. N.

    2013-12-01

    The problem of water wave scattering by a thin vertical elastic plate submerged in uniform finite depth water is investigated here. The boundary condition on the elastic plate is derived from the Bernoulli-Euler equation of motion satisfied by the plate. Using the Green's function technique, from this boundary condition, the normal velocity of the plate is expressed in terms of the difference between the velocity potentials (unknown) across the plate. The two ends of the plate are either clamped or free. The reflection and transmission coefficients are obtained in terms of the integrals' involving combinations of the unknown velocity potential on the two sides of the plate, which satisfy three simultaneous integral equations and are solved numerically. These coefficients are computed numerically for various values of different parameters and depicted graphically against the wave number in a number of figures.

  7. Initial stage of flat plate impact onto liquid free surface

    Science.gov (United States)

    Iafrati, Alessandro; Korobkin, Alexander A.

    2004-07-01

    The liquid flow and the free surface shape during the initial stage of flat plate impact onto liquid half-space are investigated. Method of matched asymptotic expansions is used to derive equations of motion and boundary conditions in the main flow region and in small vicinities of the plate edges. Asymptotic analysis is performed within the ideal and incompressible liquid model. The liquid flow is assumed potential and two dimensional. The ratio of the plate displacement to the plate width plays the role of a small parameter. In the main region the flow is given in the leading order by the pressure-impulse theory. This theory provides the flow field around the plate after a short acoustic stage and predicts unbounded velocity of the liquid at the plate edges. In order to resolve the singular flow caused by the normal impact of a flat plate, the fine pattern of the flow in small vicinities of the plate edges is studied. It is shown that the initial flow close to the plate edges is self-similar in the leading order and is governed by nonlinear boundary-value problem with unknown shape of the free surface. The Kutta conditions are imposed at the plate edges, in order to obtain a nonsingular inner solution. This boundary-value problem is solved numerically by iterations. At each step of iterations the "inner" velocity potential is calculated by the boundary-element method. The asymptotics of the inner solution in both the far field and the jet region are obtained to make the numerical algorithm more efficient. The numerical procedure is carefully verified. Agreement of the computed free surface shape with available experimental data is fairly good. Stability of the numerical solution and its convergence are discussed.

  8. Objects in Motion

    Science.gov (United States)

    Damonte, Kathleen

    2004-01-01

    One thing scientists study is how objects move. A famous scientist named Sir Isaac Newton (1642-1727) spent a lot of time observing objects in motion and came up with three laws that describe how things move. This explanation only deals with the first of his three laws of motion. Newton's First Law of Motion says that moving objects will continue…

  9. Eddy current thickness measurement apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, Gary J.; Sinclair, Frank; Soskov, Alexander; Buff, James S.

    2015-06-16

    A sheet of a material is disposed in a melt of the material. The sheet is formed using a cooling plate in one instance. An exciting coil and sensing coil are positioned downstream of the cooling plate. The exciting coil and sensing coil use eddy currents to determine a thickness of the solid sheet on top of the melt.

  10. Dynamics of Shells and Fluid-Loaded Plates.

    Science.gov (United States)

    Wang, Zhang

    This thesis is composed of two parts. The first part is concerned with wave propagation on elastic structures in vacuum. An asymptotic approximation is obtained for the dispersion relation of flexural waves propagating in an infinite, flat plate, with material and/or geometric properties periodic in one direction. A matrix approach is proposed to investigate waves in circular cylindrical thin shells joined with circular plates. Both the general propagator matrix and S-matrix formalisms are presented, with emphasis on the latter. The second part is devoted to structures with ambient fluid loading. The Green's function for a fluid-loaded plate under line loading is expressed as a sum of five fluid-loaded plate waves and an acoustic wave with magnitude given by an infinite integral, similar to a branch cut integral. A scattering matrix approach is presented to solve wave propagation problems on fluid-loaded plates with attached ribs. The low frequency asymptotic dispersion relation for a fluid-loaded plate with infinite number of equally spaced identical ribs is derived, from which an equation of motion for the plate is inferred which is valid also at low frequencies.

  11. Dynamic Behaviors of Axially Moving Viscoelastic Plate with Varying Thicknessn

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yinfeng; WANG Zhongmin

    2009-01-01

    Structural components of varying thickness draw increasing attention these days due to economy and light-weight considerations. In view of the absence of research in vibration analysis of viscoelastic plate with varying thickness, this study devotes to investigate the dynamic behaviors of axially moving viscoelastic plate with varying thickness. Based on the thin plate theory and the two-dimensional viscoelastic differential constitutive relation, the differential equation of motion of the axially moving viscoelastic rectangular plate is derived, the plate constituted by Kelvin-Voigt model has linearly varying thickness in the y-direction. The dimensionless complex frequencies of axially moving viscoelastic plate with four edges simply supported are calculated by the differential quadrature method, curves of real parts and imaginary parts of the first three-order dimensionless complex frequencies versus dimensionless moving speed are obtained, the effects of the aspect ratio, thickness ratio, the dimensionless moving speed and delay time on the dynamic behaviors of the axially moving viscoelastic rectangular plate with varying thickness are analyzed. When other parameters keep constant, with the decrease of thickness ratio, the real parts of the first three-order natural frequencies decrease, and the critical divergence speeds of various modes decrease too, moreover, whether the delay time is large or small, the frequencies are all complex numbers.

  12. Pre-plate tectonics and structure of the Archean mantle lithosphere imaged by seismic anisotropy - inferences from the LAPNET array in northern Fennoscandia

    Science.gov (United States)

    Plomerova, Jaroslava; Vecsey, Ludek; Babuska, Vladislav; Lapnet Working Group

    2013-04-01

    unstable stagnant lithospheric lid models in the Archean (~4.0 Ga), both evolving into the modern-style plate tectonics (Ernst 2007). The stage of platelets or supercratonal lasted during the deep mantle and plume-driven circulations, when plate motions were controlled by asthenospheric convection dragging buoyant lithosphere along and down. Differential motions between pairs of Precambrian cratons indicated in paleomagnetic records suggest supercontinental amalgamation and dispersal involving Archean cratons. Current thick and cold Archean cratons are thus formed by a collage of fragments of old lithosphere, each of them retaining its fabric. Studies of fossil anisotropy preserved in the mantle lithosphere contribute both to mapping the lithosphere-asthenosphere boundary and deciphering boundaries of individual blocks building the continental lithosphere (Plomerova and Babuska, Lithos 2010).

  13. Predictive coding for motion stimuli in human early visual cortex

    NARCIS (Netherlands)

    Schellekens, Wouter; van Wezel, Richard J A; Petridou, Natalia; Ramsey, Nick F.; Raemaekers, Mathijs

    2016-01-01

    The current study investigates if early visual cortical areas, V1, V2 and V3, use predictive coding to process motion information. Previous studies have reported biased visual motion responses at locations where novel visual information was presented (i.e., the motion trailing edge), which is plausi

  14. Predictive coding for motion stimuli in human early visual cortex

    NARCIS (Netherlands)

    Schellekens, Wouter; Wezel, van Richard J.A.; Petridou, Natalia; Ramsey, Nick F.; Raemeakers, Mathijs; Zaborszky, L.; Zilles, K.

    2014-01-01

    The current study investigates if early visual cortical areas, V1, V2 and V3, use predictive coding to process motion information. Previous studies have reported biased visual motion responses at locations where novel visual information was presented (i.e., the motion trailing edge), which is plausi

  15. Smoothing Motion Estimates for Radar Motion Compensation.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-07-01

    Simple motion models for complex motion environments are often not adequate for keeping radar data coherent. Eve n perfect motion samples appli ed to imperfect models may lead to interim calculations e xhibiting errors that lead to degraded processing results. Herein we discuss a specific i ssue involving calculating motion for groups of pulses, with measurements only available at pulse-group boundaries. - 4 - Acknowledgements This report was funded by General A tomics Aeronautical Systems, Inc. (GA-ASI) Mission Systems under Cooperative Re search and Development Agre ement (CRADA) SC08/01749 between Sandia National Laboratories and GA-ASI. General Atomics Aeronautical Systems, Inc. (GA-ASI), an affilia te of privately-held General Atomics, is a leading manufacturer of Remotely Piloted Aircraft (RPA) systems, radars, and electro-optic and rel ated mission systems, includin g the Predator(r)/Gray Eagle(r)-series and Lynx(r) Multi-mode Radar.

  16. Plate tectonics and crustal deformation around the Japanese Islands

    Science.gov (United States)

    Hashimoto, Manabu; Jackson, David D.

    1993-01-01

    We analyze over a century of geodetic data to study crustal deformation and plate motion around the Japanese Islands, using the block-fault model for crustal deformation developed by Matsu'ura et al. (1986). We model the area including the Japanese Islands with 19 crustal blocks and 104 faults based on the distribution of active faults and seismicity. Geodetic data are used to obtain block motions and average slip rates of faults. This geodetic model predicts that the Pacific plate moves N deg 69 +/- 2 deg W at about 80 +/- 3 mm/yr relative to the Eurasian plate which is much lower than that predicted in geologic models. Substantial aseismic slip occurs on the subduction boundaries. The block containing the Izu Peninsula may be separated from the rigid part of the Philippine Sea plate. The faults on the coast of Japan Sea and the western part of the Median Tectonic Line have slip rates exceeding 4 mm/yr, while the Fossa Magna does not play an important role in the tectonics of the central Japan. The geodetic model requires the division of northeastern Japan, contrary to the hypothesis that northeastern Japan is a part of the North American plate. Owing to rapid convergence, the seismic risk in the Nankai trough may be larger than that of the Tokai gap.

  17. Plate tectonics and crustal deformation around the Japanese Islands

    Science.gov (United States)

    Hashimoto, Manabu; Jackson, David D.

    1993-01-01

    We analyze over a century of geodetic data to study crustal deformation and plate motion around the Japanese Islands, using the block-fault model for crustal deformation developed by Matsu'ura et al. (1986). We model the area including the Japanese Islands with 19 crustal blocks and 104 faults based on the distribution of active faults and seismicity. Geodetic data are used to obtain block motions and average slip rates of faults. This geodetic model predicts that the Pacific plate moves N deg 69 +/- 2 deg W at about 80 +/- 3 mm/yr relative to the Eurasian plate which is much lower than that predicted in geologic models. Substantial aseismic slip occurs on the subduction boundaries. The block containing the Izu Peninsula may be separated from the rigid part of the Philippine Sea plate. The faults on the coast of Japan Sea and the western part of the Median Tectonic Line have slip rates exceeding 4 mm/yr, while the Fossa Magna does not play an important role in the tectonics of the central Japan. The geodetic model requires the division of northeastern Japan, contrary to the hypothesis that northeastern Japan is a part of the North American plate. Owing to rapid convergence, the seismic risk in the Nankai trough may be larger than that of the Tokai gap.

  18. Isla Guadalupe, Mexico (GUAX, SCIGN/PBO) a Relative Constraint for California Borderland and Northern Gulf of California Motions.

    Science.gov (United States)

    Gonzalez-Garcia, J. J.

    2004-12-01

    Using ITRF2000 as a common reference frame link, I analyzed survey mode and permanent GPS published results, together with SOPAC public data and results (http://sopac.ucsd.edu), in order to evaluate relative present day crustal deformation in California and northern Mexico. The crustal velocity field of Mexico (Marquez-Azua and DeMets, 2003) obtained from continuous GPS measurements conducted by Instituto Nacional de Geografia e Informatica (INEGI) for 1993-2001, was partially used. The preferred model for an instantaneous rigid motion between North-America and Pacific plates (NAPA), is obtained using results of Isla Guadalupe GPS surveys (1991-2002) giving a new constraint for Pacific plate (PA) motion (Gonzalez-Garcia et al., 2003). It produces an apparent reduction of 1 mm/yr in the absolute motion in the border zone between PA and North-America (NA) plates in this region, as compared with other GPS models (v.g. Prawirodirdjo and Bock, 2004); and it is 3 mm/yr higher than NNRNUVEL-1A. In the PA reference frame, westernmost islands from San Francisco (FARB), Los Angeles (MIG1), and Ensenada (GUAX); give current residuals of 1.8, 1.7 and 0.9 mm/yr and azimuths that are consistent with local tectonic setting, respectively. In the NA reference frame, besides the confirmation of 2 mm/yr E-W extension for the southern Basin and Range province in northern Mexico; a present day deformation rate of 40.5 mm/yr between San Felipe, Baja California (SFBC) and Hermosillo, Sonora, is obtained. This rate agrees with a 6.3 to 6.7 Ma for the "initiation of a full sea-floor spreading" in the northern Gulf of California. SFBC has a 7 mm/yr motion in the PA reference frame, giving then, a full NAPA theoretical absolute motion of 47.5 mm/yr. For Puerto Penasco, Sonora (PENA) there is a NAPA motion of 46.2 mm/yr and a residual of 1.2 mm/yr in the NA reference frame, this site is located only 75 km to the northeast from the Wagner basin center. For southern Isla Guadalupe (GUAX) there

  19. Rolling Shutter Motion Deblurring

    KAUST Repository

    Su, Shuochen

    2015-06-07

    Although motion blur and rolling shutter deformations are closely coupled artifacts in images taken with CMOS image sensors, the two phenomena have so far mostly been treated separately, with deblurring algorithms being unable to handle rolling shutter wobble, and rolling shutter algorithms being incapable of dealing with motion blur. We propose an approach that delivers sharp and undis torted output given a single rolling shutter motion blurred image. The key to achieving this is a global modeling of the camera motion trajectory, which enables each scanline of the image to be deblurred with the corresponding motion segment. We show the results of the proposed framework through experiments on synthetic and real data.

  20. Ultrasensitive, passive and wearable sensors for monitoring human muscle motion and physiological signals.

    Science.gov (United States)

    Cai, Feng; Yi, Changrui; Liu, Shichang; Wang, Yan; Liu, Lacheng; Liu, Xiaoqing; Xu, Xuming; Wang, Li

    2016-03-15

    Flexible sensors have attracted more and more attention as a fundamental part of anthropomorphic robot research, medical diagnosis and physical health monitoring. Here, we constructed an ultrasensitive and passive flexible sensor with the advantages of low cost, lightness and wearability, electric safety and reliability. The fundamental mechanism of the sensor is based on triboelectric effect inducing electrostatic charges on the surfaces between two different materials. Just like a plate capacitor, current will be generated while the distance or size of the parallel capacitors changes caused by the small mechanical disturbance upon it and therefore the output current/voltage will be produced. Typically, the passive sensor unambiguously monitors muscle motions including hand motion from stretch-clench-stretch, mouth motion from open-bite-open, blink and respiration. Moreover, this sensor records the details of the consecutive phases in a cardiac cycle of the apex cardiogram, and identify the peaks including percussion wave, tidal wave and diastolic wave of the radial pulse wave. To record subtle human physiological signals including radial pulsilogram and apex cardiogram with excellent signal/noise ratio, stability and reproducibility, the sensor shows great potential in the applications of medical diagnosis and daily health monitoring.

  1. MyPlate Food Guide

    Science.gov (United States)

    ... Choosing the Right Sport for You Shyness MyPlate Food Guide KidsHealth > For Teens > MyPlate Food Guide Print ... other sugary drinks. Avoid oversized portions. continue Five Food Groups Different food groups meet different nutrition needs. ...

  2. What Are Growth Plate Injuries?

    Science.gov (United States)

    ... plate injuries are:  Falling down  Competitive sports (like football)  Recreational activities. Other reasons for growth plate injuries are:  Child abuse  Injury from extreme cold (for ...

  3. Virtual instrument for monitoring process of brush plating

    Institute of Scientific and Technical Information of China (English)

    JING Xue-dong; XU Bin-shi; WANG Cheng-tao; ZHU Sheng; DONG Shi-yun

    2004-01-01

    A virtual instrument(Ⅵ) was developed to monitor the technological parameters in the process of brush plating, including coating thickness, brush-plating current, current density, deposition rate, and brush plating voltage. Meanwhile two approaches were presented to improve the measurement accuracy of coating thickness. One of them aims at eliminating the random interferences by moving average filtering; while the other manages to calculate the quantity of electricity consumed accurately with rectangular integration. With these two approaches, the coating thickness can be measured in real time with higher accuracy than the voltage-frequency conversion method. During the process of plating all the technological parameters are displayed visually on the front panel of the Ⅵ. Once brush current or current density overruns the limited values, or when the coating thickness reaches the objective value, the virtual will alarm. With this Ⅵ, the solution consumption can be decreased and the operating efficiency is improved.

  4. Multipactor saturation in parallel-plate waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Sorolla, E.; Mattes, M. [Ecole Polytechnique Federale de Lausanne, Laboratoire d' Electromagnetisme et d' Acoustique (LEMA), Station 11, CH-1015 Lausanne (Switzerland)

    2012-07-15

    The saturation stage of a multipactor discharge is considered of interest, since it can guide towards a criterion to assess the multipactor onset. The electron cloud under multipactor regime within a parallel-plate waveguide is modeled by a thin continuous distribution of charge and the equations of motion are calculated taking into account the space charge effects. The saturation is identified by the interaction of the electron cloud with its image charge. The stability of the electron population growth is analyzed and two mechanisms of saturation to explain the steady-state multipactor for voltages near above the threshold onset are identified. The impact energy in the collision against the metal plates decreases during the electron population growth due to the attraction of the electron sheet on the image through the initial plate. When this growth remains stable till the impact energy reaches the first cross-over point, the electron surface density tends to a constant value. When the stability is broken before reaching the first cross-over point the surface charge density oscillates chaotically bounded within a certain range. In this case, an expression to calculate the maximum electron surface charge density is found whose predictions agree with the simulations when the voltage is not too high.

  5. Controlling Laminate Plate Elastic Behavior

    OpenAIRE

    Mareš, T.

    2004-01-01

    This paper aims to express the relation of a measure of laminate plate stiffness with respect to the fiber orientation of its plies. The inverse of the scalar product of the lateral displacement of the central plane and lateral loading of the plate is the measure of laminate plate stiffness. In the case of a simply supported rectangular laminate plate this measure of stiffness is maximized, and the optimum orientation of its plies is searched.

  6. Structural motion engineering

    CERN Document Server

    Connor, Jerome

    2014-01-01

    This innovative volume provides a systematic treatment of the basic concepts and computational procedures for structural motion design and engineering for civil installations. The authors illustrate the application of motion control to a wide spectrum of buildings through many examples. Topics covered include optimal stiffness distributions for building-type structures, the role of damping in controlling motion, tuned mass dampers, base isolation systems, linear control, and nonlinear control. The book's primary objective is the satisfaction of motion-related design requirements, such as restrictions on displacement and acceleration. The book is ideal for practicing engineers and graduate students. This book also: ·         Broadens practitioners' understanding of structural motion control, the enabling technology for motion-based design ·         Provides readers the tools to satisfy requirements of modern, ultra-high strength materials that lack corresponding stiffness, where the motion re...

  7. Magnetic damping: Analysis of an eddy current brake using an airtrack

    Science.gov (United States)

    Cadwell, Louis H.

    1996-07-01

    A simple theory is proposed using Faraday's law and the Lorentz force to analyze the effect of magnetic damping on an aluminum plate moving on a horizontal air track as it passes between the poles of a horseshoe magnet. The position, velocity, and acceleration of the nonmagnetic conducting plate are measured as a function of time using a motion detector. Using some simplifying assumptions, a theoretical model is obtained in which a single free parameter is used to fit the experimental data. This parameter corresponds to an effective length (LR) in which the eddy current encounters resistance as it moves around a closed path in the conductor. This leads to some interesting, but unexpected, results about the shape and magnitude of induced eddy currents.

  8. Microchannel plate streak camera

    Science.gov (United States)

    Wang, Ching L.

    1989-01-01

    An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras. The improved streak camera is far more sensitive to photons (UV to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1000 KeV x-rays.

  9. Electronic Equipment Cold Plates

    Science.gov (United States)

    1976-04-01

    equations for such a flow regiae. For laainar flow and Moderate teaperature differwwe« between the well «nd coolant, a aodifled Sieder -Tate...con- figuration. The heat-transfer coefficients, therefore, were determined by using both the Sieder -Tate and McAdams equations and the coaputed...values used In the analytical predictions. As with th* previous cold Plates, the Sieder -Tate equation gave too low of values for the heat- transfer

  10. Elastic plate spallation

    Science.gov (United States)

    Oline, L.; Medaglia, J.

    1972-01-01

    The dynamic finite element method was used to investigate elastic stress waves in a plate. Strain displacement and stress strain relations are discussed along with the stiffness and mass matrix. The results of studying point load, and distributed load over small, intermediate, and large radii are reported. The derivation of finite element matrices, and the derivation of lumped and consistent matrices for one dimensional problems with Laplace transfer solutions are included. The computer program JMMSPALL is also included.

  11. Modal radiation patterns of baffled circular plates and membranes

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lehrmann; Hansen, Ole; Thomsen, Erik Vilain

    2014-01-01

    The far field velocity potential and radiation pattern of baffled circular plates and membranes are found analytically using the full set of modal velocity profiles derived from the corresponding equation of motion. The derivation is valid for a plate or membrane subjected to an external excitation...... that of a monopole, while the non-axisymmetric modes exhibit multipole behavior. Numerical results are also given, demonstrating the implications of having non-axisymmetric excitation using both a point excitation with varying eccentricity and a homogeneous excitation acting on half of the circular radiator....

  12. A diffuse plate boundary model for Indian Ocean tectonics

    Science.gov (United States)

    Wiens, D. A.; Demets, C.; Gordon, R. G.; Stein, S.; Argus, D.

    1985-01-01

    It is suggested that motion along the virtually aseismic Owen fracture zone is negligible, so that Arabia and India are contained within a single Indo-Arabian plate divided from the Australian plate by a diffuse boundary. The boundary is a zone of concentrated seismicity and deformation commonly characterized as 'intraplate'. The rotation vector of Australia relative to Indo-Arabia is consistent with the seismologically observed 2 cm/yr of left-lateral strike-slip along the Ninetyeast Ridge, north-south compression in the Central Indian Ocean, and the north-south extension near Chagos.

  13. Tropical Cyclone Structure and Motion

    Science.gov (United States)

    2016-06-07

    rotational motion of the storm due to storm tilt that was identified in dry simulations is reduced in simulations that include parameterizations of convective...right of the zero-shear storm track. Currently, the model resolution is being increased to 5 km with a third inner mesh and all convective processes...that were previously parameterized on the 15- and 45-km meshes are calculated using an explicit physical representation of convection scheme. Because

  14. Optical characterization of a miniaturized large field of view motion sensor

    Science.gov (United States)

    Moens, Els; Ottevaere, Heidi; Meuret, Youri; Thienpont, Hugo

    2012-06-01

    In this paper we discuss the geometrical and optical characterization of a miniaturized very wide field-of-view (FOV) motion sensor inspired by the working principle of insect facet eyes. The goal of the sensor is to detect movement in the environment and to specify where in the surroundings these changes took place. Based on the measurements of the sensor, certain actions can be taken such as sounding an alarm in security applications or turning on the light in domotic applications. The advantage of miniaturizing these sensors is that they are low-cost, compact and more esthetical compared to current motion detectors. The sensor was designed to have a very large FOV of 125° and an angular resolution of 1° or better. The micro-optics is built up of two stacked polymer plates consisting each out of a five by five lens array. In between there is a plate of absorbing material with a five by five array of baffles to create 25 optically isolated channels that each image part of the total FOV of 125° onto the detector. To geometrically characterize the lens arrays and verify the designed specifications, we made use of a coordinate measuring machine. The optical performance of the designed micro-optical system was analyzed by sending white light beams with different angles of incidence with respect to the sample through the sensor, comparing the position of the light spots visible on the detector and determining optical quality parameters such as MTF and distortion.

  15. Motion Control of Disc Electrode by Electrorheological Fluids

    Science.gov (United States)

    Tsuda, Kazutoshi; Hirose, Yuji; Ogura, Hironao; Otsubo, Yasufumi

    2008-07-01

    The electrorheological(ER) suspensions are sandwiched between two flat disc electrodes with the radial line patterns. The pattern electrodes are fixed on the parallel plate geometry on a stress-controlled rheometer which was modified for the ER experiments. The motion of disk electrodes analyzed as a function of electrification modes to obtain the basic data for ER actuators.

  16. MyPlate, Children, and Formative Evaluation

    Directory of Open Access Journals (Sweden)

    Nina Roofe

    2013-10-01

    Full Text Available Beginning at the critical preschool level, preventing childhood obesity is a multifaceted challenge with health, economic, ethical, and social implications. In particular, increasing emphasis will be placed upon educating children and their caregivers about the USDA’s MyPlate model of good nutrition. To date, evidence-based efforts to teach preschool children nutrition facts and appropriate behaviors are limited, and developers of evidence-based practices do not appear to use formative-evaluation to an adequate extent. Crucial among these evaluations is assessing what the preschool child already knows about the MyPlate components (fruits, vegetables, grains, protein, and dairy. University researchers along with graduate students in nutrition and psychology conducted a review of current research regarding the use of MyPlate in early childhood education settings. Minimal empirical studies were found, indicating a need to expand the literature in the areas of MyPlate, early childhood nutrition education, and formative evaluation. In the current article, authors present the systematic review process of the scant knowledge that exists regarding formative evaluation research to document what preschool-age children already know about nutrition, suggest ways that this research base might be expanded, and advocate for the increased use of formative evaluation in both research and curriculum development.

  17. Resistive Plate Chamber Efficiency & Rate Capability Analysis

    Science.gov (United States)

    Candocia, Max

    2012-10-01

    Bakelite-based resistive plate chambers (RPCs) are particle detectors commonly used in muon trigger systems for high-energy physics experiments. Bakelite RPCs combine fast response, sufficient position resolution and low cost, and they can be operated at instantaneous background rates up to approximately 1.5 kHz/cm^2. Current and future collider experiments will demand operation of trigger RPCs under background rates higher than what is currently achieved. The rate capability is related to the bulk and surface conductivities of the Bakelite material used for the plates bordering the active gas volume in the RPCs. At the LHC and RHIC, these surfaces are coated with linseed oil, which lowers the surface resistivity of the Bakelite, which, to a point, improves the rate capability of the detectors. We have doped our own plates with various concentrations of carbon black. Over the past year we have tested RPCs with Bakelite plates of different resistivity using cosmic ray muons and radioactive Fe55 sources to emulate different levels of background in the detector. Results on the RPC efficiencies at different background rates and for different Bakelite coatings will be presented.

  18. A form of MHD universal equations of unsteady incompressible fluid flow with variable elctroconductivity on heated moving plate

    Directory of Open Access Journals (Sweden)

    Boričić Zoran

    2005-01-01

    Full Text Available This paper deals with laminar, unsteady flow of viscous, incompressible and electro conductive fluid caused by variable motion of flat plate. Fluid electro conductivity is variable. Velocity of the plate is time function. Plate moves in its own plane and in "still" fluid. Present external magnetic filed is perpendicular to the plate. Plate temperature is a function of longitudinal coordinate and time. Viscous dissipation, Joule heat, Hole and polarization effects are neglected. For obtaining of universal equations system general similarity method is used as well as impulse and energy equation of described problem.

  19. Vehicle License Plate Recognition Syst

    Directory of Open Access Journals (Sweden)

    Meenakshi,R. B. Dubey

    2012-12-01

    Full Text Available The vehicle license plate recognition system has greater efficiency for vehicle monitoring in automatic zone access control. This Plate recognition system will avoid special tags, since all vehicles possess a unique registration number plate. A number of techniques have been used for car plate characters recognition. This system uses neural network character recognition and pattern matching of characters as two character recognition techniques. In this approach multilayer feed-forward back-propagation algorithm is used. The performance of the proposed algorithm has been tested on several car plates and provides very satisfactory results.

  20. Operative Cost Comparison: Plating Versus Intramedullary Fixation for Clavicle Fractures.

    Science.gov (United States)

    Hanselman, Andrew E; Murphy, Timothy R; Bal, George K; McDonough, E Barry

    2016-09-01

    Although clavicle fractures often heal well with nonoperative management, current literature has shown improved outcomes with operative intervention for specific fracture patterns in specific patient types. The 2 most common methods of midshaft clavicle fracture fixation are intramedullary and plate devices. Through retrospective analysis, this study performed a direct cost comparison of these 2 types of fixation at a single institution over a 5-year period. Outcome measures included operative costs for initial surgery and any hardware removal surgeries. This study reviewed 154 patients (157 fractures), and of these, 99 had intramedullary fixation and 58 had plate fixation. A total of 80% (79 of 99) of intramedullary devices and 3% (2 of 58) of plates were removed. Average cost for initial intramedullary placement was $2955 (US dollars) less than that for initial plate placement (Pcost for removal was $1874 less than that for plate removal surgery (P=.2). Average total cost for all intramedullary surgeries was $1392 less than the average cost for all plating surgeries (Pcost for all intramedullary surgeries requiring plate placement and removal was $653 less than the average cost for all plating surgeries that involved only placement (P=.04). Intramedullary fixation of clavicle fractures resulted in a statistically significant cost reduction compared with plate fixation, despite the incidence of more frequent removal surgeries. [Orthopedics.2016; 39(5):e877-e882.].

  1. In Vivo Imaging Reveals Composite Coding for Diagonal Motion in the Drosophila Visual System

    Science.gov (United States)

    Zhou, Wei; Chang, Jin

    2016-01-01

    Understanding information coding is important for resolving the functions of visual neural circuits. The motion vision system is a classic model for studying information coding as it contains a concise and complete information-processing circuit. In Drosophila, the axon terminals of motion-detection neurons (T4 and T5) project to the lobula plate, which comprises four regions that respond to the four cardinal directions of motion. The lobula plate thus represents a topographic map on a transverse plane. This enables us to study the coding of diagonal motion by investigating its response pattern. By using in vivo two-photon calcium imaging, we found that the axon terminals of T4 and T5 cells in the lobula plate were activated during diagonal motion. Further experiments showed that the response to diagonal motion is distributed over the following two regions compared to the cardinal directions of motion—a diagonal motion selective response region and a non-selective response region—which overlap with the response regions of the two vector-correlated cardinal directions of motion. Interestingly, the sizes of the non-selective response regions are linearly correlated with the angle of the diagonal motion. These results revealed that the Drosophila visual system employs a composite coding for diagonal motion that includes both independent coding and vector decomposition coding. PMID:27695103

  2. Using plate mapping to examine portion size and plate composition for large and small divided plates.

    Science.gov (United States)

    Sharp, David E; Sobal, Jeffery; Wansink, Brian

    2014-12-01

    Does the size of a plate influence the serving of all items equally, or does it influence the serving of some foods - such as meat versus vegetables - differently? To examine this question, we used the new method of plate mapping, where people drew a meal on a paper plate to examine sensitivity to small versus large three-compartment divided plates in portion size and meal composition in a sample of 109 university students. The total drawn meal area was 37% bigger on large plates than small plates, which showed that the portion of plate coverage did not differ by plate size. Men and women drew bigger vegetable portions and men drew bigger meat portions on large plates when compared to small plates. These results suggest that men and women are differentially sensitive to plate size for overall meal size and for meal composition. Implications for decreasing portion size and improving meal balance are that plate size may influence portion size and change the proportions of foods served.

  3. Ultrasound-induced acoustophoretic motion of microparticles in three dimensions

    CERN Document Server

    Muller, Peter B; Marin, Alvaro G; Barnkob, Rune; Augustsson, Per; Laurell, Thomas; Kaehler, Christian J; Bruus, Henrik

    2013-01-01

    We derive analytical expressions for the three-dimensional (3D) acoustophoretic motion of spherical microparticles in rectangular microchannels. The motion is generated by the acoustic radiation force and the acoustic streaming-induced drag force. In contrast to the classical theory of Rayleigh streaming in shallow, infinite, parallel-plate channels, our theory does include the effect of the microchannel side walls. The resulting predictions agree well with numerics and experimental measurements of the acoustophoretic motion of polystyrene spheres with nominal diameters of 0.537 um and 5.33 um. The 3D particle motion was recorded using astigmatism particle tracking velocimetry under controlled thermal and acoustic conditions in a long, straight, rectangular microchannel actuated in one of its transverse standing ultrasound-wave resonance modes with one or two half-wavelengths. The acoustic energy density is calibrated in situ based on measurements of the radiation dominated motion of large 5-um-diam particles...

  4. Stability of active mantle upwelling revealed by net characteristics of plate tectonics.

    Science.gov (United States)

    Conrad, Clinton P; Steinberger, Bernhard; Torsvik, Trond H

    2013-06-27

    Viscous convection within the mantle is linked to tectonic plate motions and deforms Earth's surface across wide areas. Such close links between surface geology and deep mantle dynamics presumably operated throughout Earth's history, but are difficult to investigate for past times because the history of mantle flow is poorly known. Here we show that the time dependence of global-scale mantle flow can be deduced from the net behaviour of surface plate motions. In particular, we tracked the geographic locations of net convergence and divergence for harmonic degrees 1 and 2 by computing the dipole and quadrupole moments of plate motions from tectonic reconstructions extended back to the early Mesozoic era. For present-day plate motions, we find dipole convergence in eastern Asia and quadrupole divergence in both central Africa and the central Pacific. These orientations are nearly identical to the dipole and quadrupole orientations of underlying mantle flow, which indicates that these 'net characteristics' of plate motions reveal deeper flow patterns. The positions of quadrupole divergence have not moved significantly during the past 250 million years, which suggests long-term stability of mantle upwelling beneath Africa and the Pacific Ocean. These upwelling locations are positioned above two compositionally and seismologically distinct regions of the lowermost mantle, which may organize global mantle flow as they remain stationary over geologic time.

  5. Temperature field of steel plate cooling process after plate rolling

    Directory of Open Access Journals (Sweden)

    Huijun Feng, Lingen Chen, Fengrui Sun

    2015-01-01

    Full Text Available Based on numerical calculation with Matlab, the study on cooling process after plate rolling is carried out, and the temperature field distribution of the plate varying with the time is obtained. The effects of the plate thickness, final rolling temperature, cooling water temperature, average flow rate of the cooling water, carbon content of the plate and cooling method on the plate surface and central temperatures as well as final cooling temperature are discussed. For the same cooling time, the plate surface and central temperatures as well as their temperature difference increase; with the decrease in rolling temperature and the increase in average flow rate of the cooling water, the plate surface and central temperatures decrease. Compared with the single water cooling process, the temperature difference between the plate centre and surface based on intermittent cooling is lower. In this case, the temperature uniformity of the plate is better, and the corresponding thermal stress is lower. The fitting equation of the final cooling temperature with respect to plate thickness, final rolling temperature, cooling water temperature and average flow rate of the cooling water is obtained.

  6. LOWLID FORMATION AND PLATE TECTONICS ON EXOPLANETS

    Science.gov (United States)

    Stamenkovic, V.; Noack, L.; Breuer, D.

    2009-12-01

    The last years of astronomical observation have opened the doors to a universe filled with extrasolar planets. Detection techniques still only offer the possibility to detect mainly Super-Earths above five Earth masses. But detection techniques do steadily improve and are offering the possibility to detect even smaller planets. The observations show that planets seem to exist in many possible sizes just as the planets and moons of our own solar system do. It is only a natural question to ask if planetary mass has an influence on some key habitability factors such as on plate tectonics, allowing us to test which exoplanets might be more likely habitable than others, and allowing us to understand if plate tectonics on Earth is a stable or a critical, instable process that could easily be perturbed. Here we present results derived from 1D parameterized thermal evolution and 2D/3D computer models, showing how planetary mass influences the propensity of plate tectonics for planets with masses ranging from 0.1 to 10 Earth masses. Lately [2, 3] studied the effect of planetary mass on the ability to break plates and hence initiate plate tectonics - but both derived results contradictory to the other. We think that one of the reasons why both studies [2, 3] are not acceptable in their current form is partly due to an oversimplification. Both treated viscosity only temperature-dependent but neglected the effect pressure has on enlarging the viscosity in the deep mantle. More massive planets have therefore a stronger pressure-viscosity-coupling making convection at high pressures sluggish or even impossible. For planets larger than two Earth masses we observe that a conductive lid (termed low-lid) forms above the core-mantle boundary and thus reduces the effective convective part of the mantle when including a pressure-dependent term into the viscosity laws as shown in [1]. Moreover [2, 3] use time independent steady state models neglecting the fact that plate tectonics is a

  7. Evolution of fuel plate parameters during deformation in rolling

    Science.gov (United States)

    Durazzo, M.; Vieira, E.; Urano de Carvalho, E. F.; Riella, H. G.

    2017-07-01

    The Nuclear and Energy Research Institute - IPEN/CNEN-SP routinely produces the nuclear fuel necessary for operating its research reactor, IEA-R1. This fuel consists of fuel plates containing U3Si2-Al composites as the meat, which are fabricated by rolling. The rolling process currently deployed was developed based on information obtained from literature, which was used as a premise for defining the current manufacturing procedures, according to a methodology with an essentially empirical character. Despite the current rolling process being perfectly stable and highly reproducible, it is not well characterized and is therefore not fully known. The objective of this work is to characterize the rolling process for producing dispersion fuel plates. Results regarding the evolution of the main parameters of technological interest, after each rolling pass, are presented. Some defects that originated along the fuel plate deformation during the rolling process were characterized and discussed. The fabrication procedures for manufacturing the fuel plates are also presented.

  8. Plate boundary deformation at the latitude of the Salton Trough - northern Gulf of California (Invited)

    Science.gov (United States)

    Stock, J. M.

    2013-12-01

    Along the Pacific-North America plate boundary zone, the segment including the southern San Andreas fault to Salton Trough and northern Gulf of California basins has been transtensional throughout its evolution, based on Pacific-North America displacement vectors calculated from the global plate circuit (900 × 20 km at N54°W since 20 Ma; 460 × 20 km at N48°W since 11 Ma). Nevertheless, active seismicity and focal mechanisms show a broad zone of plate boundary deformation within which the inferred stress regime varies locally (Yang & Hauksson 2013 GJI), and fault patterns in some regions suggest ongoing tectonic rotation. Similar behavior is inferred to have occurred in this zone over most of its history. Crustal structure in this region is constrained by surface geology, geophysical experiments (e.g., the 2011 Salton Seismic Imaging Project (SSIP), USGS Imperial Valley 1979, PACE), and interdisciplinary marine and onland studies in Mexico (e.g., NARS-Baja, Cortes, and surveys by PEMEX). Magnetic data (e.g., EMAG-2) aids in the recognition of large-scale crustal provinces and fault boundaries in regions lacking detailed geophysical surveys. Consideration of existing constraints on crustal thickness and architecture, and fault and basin evolution suggests that to reconcile geological deformation with plate motion history, the following additional factors need to be taken into account. 1) Plate boundary displacement via interacting systems of rotating blocks, coeval with slip on steep strike slip faults, and possibly related to slip on low angle extensional faults (e.g, Axen & Fletcher 1998 IGR) may be typical prior to the onset of seafloor spreading. This fault style may have accommodated up to 150 km of plate motion in the Mexican Continental Borderland and north of the Vizcaino Peninsula, likely between 12 and 15 Ma, as well as explaining younger rotations adjacent to the Gulf of California and current deformation southwest of the Salton Sea. 2) Geophysical

  9. Measurement of visual motion

    Energy Technology Data Exchange (ETDEWEB)

    Hildreth, E.C.

    1984-01-01

    This book examines the measurement of visual motion and the use of relative movement to locate the boundaries of physical objects in the environment. It investigates the nature of the computations that are necessary to perform this analysis by any vision system, biological or artificial. Contents: Introduction. Background. Computation of the Velocity Field. An Algorithm to Compute the Velocity Field. The Computation of Motion Discontinuities. Perceptual Studies of Motion Measurement. The Psychophysics of Discontinuity Detection. Neurophysiological Studies of Motion. Summary and Conclusions. References. Author and Subject Indexes.

  10. Brain Image Motion Correction

    DEFF Research Database (Denmark)

    Jensen, Rasmus Ramsbøl; Benjaminsen, Claus; Larsen, Rasmus

    2015-01-01

    The application of motion tracking is wide, including: industrial production lines, motion interaction in gaming, computer-aided surgery and motion correction in medical brain imaging. Several devices for motion tracking exist using a variety of different methodologies. In order to use such devices...... offset and tracking noise in medical brain imaging. The data are generated from a phantom mounted on a rotary stage and have been collected using a Siemens High Resolution Research Tomograph for positron emission tomography. During acquisition the phantom was tracked with our latest tracking prototype...

  11. Comparison of the peak resolution and the stationary phase retention between the satellite and the planetary motions using the coil satellite centrifuge with counter-current chromatographic separation of 4-methylumbelliferyl sugar derivatives.

    Science.gov (United States)

    Shinomiya, Kazufusa; Zaima, Kazumasa; Harada, Yukina; Yasue, Miho; Harikai, Naoki; Tokura, Koji; Ito, Yoichiro

    2017-01-20

    Coil satellite centrifuge (CSC) produces the complex satellite motion consisting of the triplicate rotation of the coiled column around three axes including the sun axis (the angular velocity, ω1), the planet axis (ω2) and the satellite axis (the central axis of the column) (ω3) according to the following formula: ω1=ω2+ω3. Improved peak resolution in the separation of 4-methylumbelliferyl sugar derivatives was achieved using the conventional multilayer coiled columns with ethyl acetate/1-butanol/water (3: 2: 5, v/v) for the lower mobile phase at the combination of the rotation speeds (ω1, ω2, ω3)=(300, 150, 150rpm), and (1:4:5, v/v) for the upper mobile phase at (300:100:200rpm). The effect of the satellite motion on the peak resolution and the stationary phase retention was evaluated by each CSC separation with the different rotation speeds of ω2 and ω3 under the constant revolution speed at ω1=300rpm. With the lower mobile phase, almost constant peak resolution and stationary phase retention were yielded regardless of the change of ω2 and ω3, while with the upper mobile phase these two values were sensitively varied according to the different combination of ω2 and ω3. For example, when ω2=147 or 200rpm is used, no stationary phase was retained in the coiled column while ω2=150rpm could retain enough volume of stationary phase for separation. On the other hand, the combined rotation speeds at (ω1, ω2, ω3)=(300, 300, 0rpm) or (300, 0, 300rpm) produced insufficient peak resolution regardless of the choice of the mobile phase apparently due to the lack of rotation speed except at (300, 0, 300rpm) with the upper mobile phase. At lower rotation speed of ω1=300rpm, better peak resolution and stationary phase retention were obtained by the satellite motion (ω3) than by the planetary motion (ω2), or ω3>ω2. The effect of the hydrophobicity of the two-phase solvent systems on the stationary phase retention was further examined using the n

  12. Wear of connector contacts exposed to relative motion

    Science.gov (United States)

    Wilk, R. A.

    Connectors play a significant role in the performance, cost, and reliability of electronic equipment. In connection with the development of the system interconnection design, a factor which is often overlooked is related to the importance of connector selection and mounting to minimize relative motion between contacts during vibration encountered in handling, transportation, and service. This motion can lead to the loss of protective coatings (gold and nickel) due to frictional wear. If this happens, fretting corrosion of the base metals may occur. The produced damage can adversely affect performance due to increased joint resistance, eventually causing intermittent contacts. The present investigation is concerned with the study of different style contacts (tuning fork, box, and circular) to determine their endurance and wear characteristics when exposed to relative motion created by vibration. All contacts investigated were fabricated from brass, beryllium copper, or phosphor bronze, and had .00127 mm minimum gold plating over .00127 mm minimum nickel plating.

  13. Plate Full of Color

    Centers for Disease Control (CDC) Podcasts

    2008-08-04

    The Eagle Books are a series of four books that are brought to life by wise animal characters - Mr. Eagle, Miss Rabbit, and Coyote - who engage Rain That Dances and his young friends in the joy of physical activity, eating healthy foods, and learning from their elders about health and diabetes prevention. Plate Full of Color teaches the value of eating a variety of colorful and healthy foods.  Created: 8/4/2008 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 8/5/2008.

  14. Dynamics of Tectonic Plates

    CERN Document Server

    Pechersky, E; Sadowski, G; Yambartsev, A

    2014-01-01

    We suggest a model that describes a mutual dynamic of tectonic plates. The dynamic is a sort of stick-slip one which is modeled by a Markov random process. The process defines a microlevel of the dynamic. A macrolevel is obtained by a scaling limit which leads to a system of integro-differential equations which determines a kind of mean field systems. Conditions when Gutenberg-Richter empirical law are presented on the mean field level. These conditions are rather universal and do not depend on features of resistant forces.

  15. Dynamics of Tectonic Plates

    OpenAIRE

    2014-01-01

    We suggest a model that describes a mutual dynamic of tectonic plates. The dynamic is a sort of stick-slip one which is modeled by a Markov random process. The process defines a microlevel of the dynamic. A macrolevel is obtained by a scaling limit which leads to a system of integro-differential equations which determines a kind of mean field systems. Conditions when Gutenberg-Richter empirical law are presented on the mean field level. These conditions are rather universal and do not depend ...

  16. The dynamics of plate tectonics and mantle flow: from local to global scales.

    Science.gov (United States)

    Stadler, Georg; Gurnis, Michael; Burstedde, Carsten; Wilcox, Lucas C; Alisic, Laura; Ghattas, Omar

    2010-08-27

    Plate tectonics is regulated by driving and resisting forces concentrated at plate boundaries, but observationally constrained high-resolution models of global mantle flow remain a computational challenge. We capitalized on advances in adaptive mesh refinement algorithms on parallel computers to simulate global mantle flow by incorporating plate motions, with individual plate margins resolved down to a scale of 1 kilometer. Back-arc extension and slab rollback are emergent consequences of slab descent in the upper mantle. Cold thermal anomalies within the lower mantle couple into oceanic plates through narrow high-viscosity slabs, altering the velocity of oceanic plates. Viscous dissipation within the bending lithosphere at trenches amounts to approximately 5 to 20% of the total dissipation through the entire lithosphere and mantle.

  17. Rupture across arc segment and plate boundaries in the 1 April 2007 Solomons earthquake

    Science.gov (United States)

    Taylor, Frederick W.; Briggs, Richard W.; Frohlich, Cliff; Brown, Abel; Hornbach, Matt; Papabatu, Alison K.; Meltzner, Aron J.; Billy, Douglas

    2008-04-01

    The largest earthquakes are generated in subduction zones, and the earthquake rupture typically extends for hundreds of kilometres along a single subducting plate. These ruptures often begin or end at structural boundaries on the overriding plate that are associated with the subduction of prominent bathymetric features of the downgoing plate. Here, we determine uplift and subsidence along shorelines for the 1 April 2007 moment magnitude MW 8.1 earthquake in the western Solomon Islands, using coral microatolls which provide precise measurements of vertical motions in locations where instrumental data are unavailable. We demonstrate that the 2007 earthquake ruptured across the subducting Simbo ridge transform and thus broke through a triple junction where the Australian and Woodlark plates subduct beneath the overriding Pacific plate. Previously, no known major megathrust rupture has involved two subducting plates. We conclude that this event illustrates the uncertainties of predicting the segmentation of subduction zone rupture on the basis of structural discontinuities.

  18. Ground motion: An introduction for accelerator builders

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, G.E.

    1992-02-01

    In this seminar we will review some of the characteristics of the major classes of ground motion in order to determine whether their effects must be considered or place fundamental limits on the sitting and/or design of modern storage rings and linear colliders. The classes discussed range in frequency content from tidal deformation and tectonic motions through earthquakes and microseisms. Countermeasures currently available are briefly discussed.

  19. Ground motion: An introduction for accelerator builders

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, G.E.

    1992-02-01

    In this seminar we will review some of the characteristics of the major classes of ground motion in order to determine whether their effects must be considered or place fundamental limits on the sitting and/or design of modern storage rings and linear colliders. The classes discussed range in frequency content from tidal deformation and tectonic motions through earthquakes and microseisms. Countermeasures currently available are briefly discussed.

  20. Automatic Grid Processing of Large Photographic Plates (With 3 Figures)

    Science.gov (United States)

    Dumoulin, B.; Québatte, J.; West, R. M.

    In an earlier article (42.034.211), the authors have described a new method for the development of large photographic plates. This method, which is called grid processing, is based on the rapid motion of a metallic grid in the developer, very close to the emulsion surface. Experience has shown that this method is superior to the classical tray rocker. The authors here report the continuation of the tests, now with the aid of the prototype of an automatic grid processing machine.